id,collection,atmire.embargo.exceeding,dc.contributor.author,dc.date.accessioned,dc.date.available,dc.date.issued,dc.date.submitted,dc.description,dc.description.abstract,dc.description.sponsorship,dc.identifier.doi,dc.identifier.eissn,dc.identifier.issn,dc.identifier.uri,dc.language.iso,dc.localisation,dc.publisher,dc.relation.projectId,dc.rights,dc.rights.cc,dc.subject,dc.subject.hal,dc.title,dc.typdoc,ensam.audience,ensam.city,ensam.conference.date,ensam.conference.title,ensam.country,ensam.embargo.lift,ensam.embargo.terms,ensam.hal.submit,ensam.import.source,ensam.invitedCommunication,ensam.issue,ensam.journal,ensam.language,ensam.mappingcollection,ensam.page,ensam.peerReviewing,ensam.proceeding,ensam.title.proceeding,ensam.volume,ensam.workflow.metadataEdited,ensam.workflow.submissionConsumer,hal.author.function,hal.date.transferred,hal.description.error,hal.identifier,hal.status,hal.submission.permitted,hal.update-error.status,hal.version,workflow.import.source
"180a6af8-3283-4c5b-894c-88d1779b7f12","10985/13599",,"AMMAR, Amine||CHINESTA, Francisco||CUETO, Elias||DOBLARÉ, Manuel","2014","2014","2012","2014",,"Models encountered in computational mechanics could involve many time scales. When these time scales cannot be separated, one must solve the evolution model in the entire time interval by using the finest time step that the model implies. In some cases, the solution procedure becomes cumbersome because of the extremely large number of time steps needed for integrating the evolution model in the whole time interval. In this paper, we considered an alternative approach that lies in separating the time axis (one-dimensional in nature) in a multidimensional time space. Then, for circumventing the resulting curse of dimensionality, the proper generalized decomposition was applied allowing a fast solution with significant computing time savings with respect to a standard incremental integration.","Spanish Ministry of Education and Science grant number (CICYT-DPI2008-00918)","10.1002/nme.3331","1097-0207","0029-5981","http://hdl.handle.net/10985/8499","en_US","Centre de Angers","Wiley",,"Post-print",,"Time multiscale||Proper generalized decomposition||Separated representations||Transient models","Sciences de l'ingénieur: Mécanique: Mécanique des matériaux","Proper generalized decomposition of time-multiscale models","Article dans une revue avec comité de lecture","Internationale",,,,,,,"running",,,"5","International Journal for Numerical Methods in Engineering",,,"569-596",,,,"90",,,"aut||aut||aut||aut",,"The argument 'doi' (value = '10.1002/nme.3331') included in the request is allready on HAL",,"unsent","true",,,
"821d1f13-db69-4a01-80a4-9b34bfd78189","10985/13599",,"GRMELA, Miroslav||AMMAR, Amine||CHINESTA, Francisco","2014","2014","2013","2014","http://dx.doi.org/10.1016/j.jnnfm.2012.10.009","The morphology influencing rheological properties of suspensions of rigid spheres constitutes the flow induced collective ordering of the spheres characterized by two or more sphere distribution functions. When the rigid spheres are replaced by rigid fibers, the collective order in the position of the spheres is replaced by the flow induced orientation of the fibers that suffices to be characterized by one-fiber orientation distribution function. A flow induced collective ordering of fibers (both in position and orientation), that can only be characterized by two or more fiber distribution functions, can still however constitute an important part of the morphology. We show that two types of interaction among fibers, one being the Onsager-type topological interaction entering the free energy and the other the hydrodynamics interaction entering the dissipative part of the time evolution, give indeed rise to a collective order in the orientation influencing the rheology of fiber suspensions.",,"10.1016/j.jnnfm.2012.10.009",,"0377-0257","http://hdl.handle.net/10985/8488","en_US","Centre de Angers","Elsevier",,"Post-print",,"Fiber orientation||Kinetic theory||Hamiltonian dynamics||Generic","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","One and two-fiber orientation kinetic theories of fiber suspensions","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Journal of Non-Newtonian Fluid Mechanics",,,"17-33",,,,"200",,,"aut||aut||aut",,"The argument 'doi' (value = '10.1016/j.jnnfm.2012.10.009') included in the request is allready on HAL",,"unsent","true",,,
"eae6344c-f836-4d54-9fd6-4e2a04c51425","10985/13599",,"CHINESTA, Francisco||AMMAR, Amine||LEYGUE, Adrien||KEUNINGS, Roland","2014","2014","2011","2014",,"We review the foundations and applications of the proper generalized decomposition (PGD), a powerful model reduction technique that computes a priori by means of successive enrichment a separated representation of the unknown field. The computational complexity of the PGD scales linearly with the dimension of the space wherein the model is defined, which is in marked contrast with the exponential scaling of standard grid-based methods. First introduced in the context of computational rheology by Ammar et al. [3] and [4], the PGD has since been further developed and applied in a variety of applications ranging from the solution of the Schrödinger equation of quantum mechanics to the analysis of laminate composites. In this paper, we illustrate the use of the PGD in four problem categories related to computational rheology: (i) the direct solution of the Fokker-Planck equation for complex fluids in configuration spaces of high dimension, (ii) the development of very efficient non-incremental algorithms for transient problems, (iii) the fully three-dimensional solution of problems defined in degenerate plate or shell-like domains often encountered in polymer processing or composites manufacturing, and finally (iv) the solution of multidimensional parametric models obtained by introducing various sources of problem variability as additional coordinates.",,"10.1016/j.jnnfm.2010.12.012",,"0377-0257","http://hdl.handle.net/10985/8473","en_US","Centre de Angers","Elsevier",,"Post-print",,"Complex fluids||Numerical modeling||Model reduction||Proper orthogonal decomposition||Proper generalized decomposition||Kinetic theory||Parametric models||Optimization||Inverse identification","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","An overview of the proper generalized decomposition with applications in computational rheology","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"11","Journal of Non-Newtonian Fluid Mechanics",,,"578-592",,,,"166",,,"aut||aut||aut||aut",,,"hal-01061441","accept","updateMetadata",,"1",
"4db7205f-f4c5-4a72-840f-d79a8ba21f71","10985/191||10985/13599",,"CASTÉRAN, Fanny||DELAGE, Karim||HASCOËT, Nicolas||AMMAR, Amine||CHINESTA, Francisco||CASSAGNAU, Philippe","2022","2022","2022",,,"Two main problems are studied in this article. The first one is the use of the extrusion process for controlled thermo-mechanical degradation of polyethylene for recycling applications. The second is the data-based modelling of such reactive extrusion processes. Polyethylenes (high density polyethylene (HDPE) and ultra-high molecular weight polyethylene (UHMWPE)) were extruded in a corotating twin-screw extruder under high temperatures (350 °C < T < 420 °C) for various process conditions (flow rate and screw rotation speed). These process conditions involved a decrease in the molecular weight due to degradation reactions. A numerical method based on the Carreau-Yasuda model was developed to predict the rheological behaviour (variation of the viscosity versus shear rate) from the in-line measurement of the die pressure. The results were successfully compared to the viscosity measured from offline measurement assuming the Cox-Merz law. Weight average molecular weights were estimated from the resulting zero-shear rate viscosity. Furthermore, the linear viscoelastic behaviours (Frequency dependence of the complex shear modulus) were also used to predict the molecular weight distributions of final products by an inverse rheological method. Size exclusion chromatography (SEC) was performed on five samples, and the resulting molecular weight distributions were compared to the values obtained with the two aforementioned techniques. The values of weight average molecular weights were similar for the three techniques. The complete molecular weight distributions obtained by inverse rheology were similar to the SEC ones for extruded HDPE samples, but some inaccuracies were observed for extruded UHMWPE samples. The Ludovic® (SC-Consultants, Saint-Etienne, France) corotating twin-screw extrusion simulation software was used as a classical process simulation. However, as the rheo-kinetic laws of this process were unknown, the software could not predict all the flow characteristics successfully. Finally, machine learning techniques, able to operate in the low-data limit, were tested to build predicting models of the process outputs and material characteristics. Support Vector Machine Regression (SVR) and sparsed Proper Generalized Decomposition (sPGD) techniques were chosen to predict the process outputs successfully. These methods were also applied to material characteristics data, and both were found to be effective in predicting molecular weights. More precisely, the sPGD gave better results than the SVR for the zero-shear viscosity prediction. Stochastic methods were also tested on some of the data and showed promising results.",,"10.3390/polym14040800",,"2073-4360","http://hdl.handle.net/10985/22199","en","Centre de Paris","MDPI AG",,"Version éditeur","CC BY","Polymers and Plastics||General Chemistry","Sciences de l'ingénieur","Data-Driven Modelling of Polyethylene Recycling under High-Temperature Extrusion","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"4","Polymers",,"10985/13599","800","Oui",,,"14","true","newSubmission","aut||aut||aut||aut||aut||aut","2022-06-29T09:41:18Z",,"hal-03708508","accept","true",,"1","crossref"
"8ac1cf49-61d3-4bad-a8af-0d30477aa39e","10985/13599",,"AMMAR, Amine||MAGNIN, Morgan||ROUX, Olivier||CUETO, Elias||CHINESTA, Francisco","2016","2016","2016","2016",,"The numerical solution of the Chemical Master Equation (CME) governing gene regulatory networks and cell signaling processes remains a challenging task due to its complexity, exponentially growing with the number of species involved. When considering separated representations of the probability distribution function within the Proper Generalized Decomposition-PGD-frame-work the complexity of the CME grows only linearly with the number of state space dimensions. In order to speed up calculations moment-based descriptions are usually preferred, however these descriptions involve the necessity of using closure relations whose impact on the calculated solution is most of time unpredictable. In this work we propose an empirical closure, fitted from the solution of the chemical master equation, the last solved within the PGD framework.",,"10.4172/2329-6577.1000155",,"2329-6577","http://hdl.handle.net/10985/11391","en","Centre de Angers","Omics Publishing Group",,"Post-print",,"Proper generalized decomposition||Chemical master equation||Curse of dimensionality||Closure relations","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Chemical Master Equation Empirical Moment Closure","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"1","Biological Systems: Open Access",,,"1-12","Oui",,,"5",,,"aut||aut||aut||aut||aut","2020-02-21T09:08:25Z",,"hal-02486645","accept","true",,"1",
"709376aa-2805-4834-be29-baeb78e9276e","10985/13599",,"AGHIGHI, Mohammad Saeid||AMMAR, Amine||METIVIER, Christel||GHARAGOZLU, M.","2019","2019","2018",,,"This study aims at investigating numerically the Rayleigh-Bénard Convection (RBC) in viscoplastic fluids. A Casson fluid is considered in a bidimensional square cavity heated from below. The effects of the dimensionless yield stress, the Bingham number Bn, on the heat transfer and motion is investigated in the range 5.10^3 < Ra < 10^5 for the Rayleigh number and Pr = 10, 100, 1000 for the Prandtl number. One shows that the yield stress has a stabilizing effect, reducing the convection intensity. Above a certain value of Bnmax , the convection does not occur and the heat transfer is only due to conduction. For moderate Bn values, truly unyielded regions are located in the center of the cavity; their areas grow with increasing Bingham number and invade the whole cavity at the threshold value Bnmax .",,"10.1016/j.ijthermalsci.2018.01.016",,"1290-0729","http://hdl.handle.net/10985/16695","en","Centre de Angers","Elsevier",,"Post-print",,,"Sciences de l'ingénieur: Mécanique","Rayleigh-Bénard convection of Casson fluids","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,,"International Journal of Thermal Sciences",,,"79-90","Oui",,,"127","true","newSubmission","aut||aut||aut||aut","2019-09-12T12:25:57Z",,"hal-02285050","accept","true",,"1","crossref||crossref"
"ca1b4326-d125-4da5-baab-c41fd97136e4","10985/191||10985/13599",,"TORREGROSA, Sergio||CHAMPANEY, Victor||AMMAR, Amine||HERBERT, Vincent||CHINESTA, Francisco","2022","2022","2021",,,"The description of a physical problem through a model necessarily involves the introduction of parameters. Hence, one wishes to have a solution of the problem that is a function of all these parameters: a parametric solution. However, the construction of such parametric solutions exhibiting localization in space is only ensured by costly and time-consuming tests, which can be both numerical or experimental. Numerical methodologies used classically imply enormous computational efforts for exploring the design space. Therefore, parametric solutions obtained using advanced nonlinear regressions are an essential tool to address this challenge. However, classical regression techniques, even the most advanced ones, can lead to non physical interpolation in some fields such as fluid dynamics, where the solution localizes in different regions depending on the problem parameters choice. In this context, Optimal Transport (OT) offers a mathematical approach to measure distances and interpolate between general objects in a, sometimes, more physical way than the classical interpolation approach. Thus, OT has become fundamental in some fields such as statistics or computer vision, and it is being increasingly used in fields such as computational mechanics. However, the OT problem is usually computationally costly to solve and not adapted to be accessed in an online manner. Therefore, the aim of this paper is combining advanced nonlinear regressions with Optimal Transport in order to implement a parametric real-time model based on OT. To this purpose, a parametric model is built offline relying on Model Order Reduction and OT, leading to a real-time interpolation tool following Optimal Transport theory. Such a tool is of major interest in design processes, but also within the digital twin rationale.",,"10.1016/j.matcom.2021.11.010",,"0378-4754","http://hdl.handle.net/10985/22204","en","Centre de Paris","Elsevier B.V.",,"Post-print","Pas de Licence CC","Applied Mathematics||Modeling and Simulation||Numerical Analysis||General Computer Science||Theoretical Computer Science","Sciences de l'ingénieur","Surrogate parametric metamodel based on Optimal Transport","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,,"Mathematics and Computers in Simulation",,"10985/13599","36-63","Oui",,,"194","true","newSubmission","aut||aut||aut||aut||aut","2022-06-29T13:33:25Z",,"hal-03709018","accept","true",,"1","crossref"
"1dbd484e-28ae-4988-804b-28a3731858e8","10985/13599",,"GMATI, Hela||MAREAU, Charles||AMMAR, Amine||EL AREM, Saber","2020","2020","2020",,,"In the present work, a phase field damage model is developed to address the numerical simulation of brittle fracture. This model successfully captures some important aspects of crack propagation, including crack branching and bifurcation. In addition, the proposed phase field model has been developed in the general framework of anisotropic elasticity. It can thus be used for the simulation of brittle fracture in polycrystalline materials, for which crack propagation is impacted by crystallographic orientation because of the anisotropic character of stiffness properties.",,"10.1002/nme.6361","1097-0207","0029-5981","http://hdl.handle.net/10985/19260","en","Centre de Angers","Wiley",,"Post-print",,"General Engineering||Applied Mathematics||Numerical Analysis","Sciences de l'ingénieur","A phase‐field model for brittle fracture of anisotropic materials","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"15","International Journal for Numerical Methods in Engineering",,,"3362-3381","Oui",,,"121","true","newSubmission","aut||aut||aut||aut","2020-09-21T13:59:37Z",,"hal-02944667","accept","true",,"1","crossref"
"9d307ab2-878f-4f38-9b47-5565006f5696","10985/191||10985/13599",,"CHAMPANEY, Victor||PASQUALE, Angelo||AMMAR, Amine||CHINESTA, Francisco","2022","2022","2022",,,"In the context of parametric surrogates, several nontrivial issues arise when a whole curve shall be predicted from given input features. For instance, different sampling or ending points lead to non-aligned curves. This also happens when the curves exhibit a common pattern characterized by critical points at shifted locations (e.g., in mechanics, the elasticplastic transition or the rupture point for a material). In such cases, classical interpolation methods fail in giving physics-consistent results and appropriate pre-processing steps are required. Moreover, when bifurcations occur into the parametric space, to enhance the accuracy of the surrogate, a coupling with clustering and classification algorithms is needed. In this work we present several methodologies to overcome these issues. We also exploit such surrogates to quantify and propagate uncertainty, furnishing parametric stastistical bounds for the predicted curves. The procedures are exemplified over two problems in Computational Mechanics.",,"10.3389/fmats.2022.904707",,"2296-8016","http://hdl.handle.net/10985/22377","en","Centre de Paris","Frontiers",,"Post-print||Post-print","Pas de Licence CC||Pas de Licence CC","Materials Science (miscellaneous)","Sciences de l'ingénieur||Sciences de l'ingénieur","Parametric Curves Metamodelling Based on Data Clustering, Data Alignment, POD-Based Modes Extraction and PGD-Based Nonlinear Regressions","Article dans une revue avec comité de lecture||Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,,"Frontiers in Materials",,"10985/13599",,"Oui",,,"9","true","newSubmission","aut||aut||aut||aut","2022-08-18T13:16:59Z",,"hal-03753637","accept","true",,"1","crossref"
"c70e87a0-5dea-4d0b-bf5a-8dcc60bf9fc3","10985/13599",,"AGHIGHI, Mohammad Saeid||AMMAR, Amine","2019","2019","2017",,,"Purpose  The purpose of this paper is to analyze two-dimensional steady-state Rayleigh–Bénard convection within rectangular enclosures in different aspect ratios filled with yield stress fluids obeying the Herschel–Bulkley model. Design/methodology/approach In this study, a numerical method based on the finite element has been developed for analyzing two-dimensional natural convection of a Herschel–Bulkley fluid. The effects of Bingham number Bn and power law index n on heat and momentum transport have been investigated for a nominal Rayleigh number range (5 × 10^3 < Ra < 10^5), three different aspect ratios (ratio of enclosure length:height AR = 1, 2, 3) and a single representative value of nominal Prandtl number (Pr = 10). Findings Results show that the mean Nusselt number Nu¯ increases with increasing Rayleigh number due to strengthening of convective transport. However, with the same nominal value of Ra, the values of Nu¯ for shear thinning fluids n < 1 are greater than shear thickening fluids n > 1. The values of Nu¯ decrease with Bingham number and for large values of Bn, Nu¯ rapidly approaches unity, which indicates that heat transfer takes place principally by thermal conduction. The effects of aspect ratios have also been investigated and results show that Nu¯ increases with increasing AR due to stronger convection effects. Originality/value This paper presents a numerical study of Rayleigh–Bérnard flows involving Herschel–Bulkley fluids for a wide range of Rayleigh numbers, Bingham numbers and power law index based on finite element method. The effects of aspect ratio on flow and heat transfer of Herschel–Bulkley fluids are also studied.",,"10.1108/ec-06-2016-0227",,"0264-4401","http://hdl.handle.net/10985/16656","en","Centre de Angers","Emerald",,"Post-print",,"General Engineering||General Engineering||Computational Theory and Mathematics||Computational Theory and Mathematics||Software||Software||Computer Science Applications||Computer Science Applications","Sciences de l'ingénieur: Mécanique","Aspect ratio effects in Rayleigh-Bénard convection of Herschel-Bulkley fluids","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref||crossref",,,"Engineering Computations",,,"19","Oui",,,,"true","newSubmission","aut||aut","2019-09-12T09:54:33Z",,"hal-02284922","accept","true",,"1","crossref"
"c02aaf60-7cbf-408e-a3fe-f6d4c4421616","10985/13599",,"CHINE, Adel||AMMAR, Amine||CLERMONT, Jean-Robert","2019","2019","2015",,,"Purpose – The purpose of this paper is to compute flow effects of the transition from adherence-to-slip in two-dimensional flows, for a polymer melt obeying a memory-integral viscoelastic equation, in isothermal and non-isothermal cases. Design/methodology/approach – Temperature dependence is expressed by Arrhenius and William-Landel-Ferry models. A coupling approach is defined. For the dynamic equations, the Stream-Tube Method (STM) is used with finite differences in a mapped rectangular domain of the real domain, where streamlines are parallel and straight. STM avoids particle-tracking problems and allows simple formulae to evaluate stresses resulting from the constitutive equation. For the temperature field, a finite-element method is carried out to solve the energy equation in the real domain.  Findings – The approach avoids numerical problems arising with classical formulations and proves to be robust and efficient. Large elasticity levels are attained without convergence and refinement difficulties that may arise close to the “stick-slip” transition section. The method highlights the role of temperature conditions and reveals interesting differences for the ducts considered.  Practical implications – The results of the study are of interest for polymer processing where slip at the wall can be encountered, in relation with the physical properties of the materials. Originality/value – The paper presents a simple approach that limits considerably numerical problems coming from stick-slip boundary conditions and avoids particle-tracking. Results are obtained at flow rates encountered in industrial conditions. Keywords Finite elements, Viscoelasticity, Stick-slip problem, Adherence-to-slip, Non-isothermal two-dimensional flows, Memory-integral models",,"10.1108/ec-02-2014-0039",,"0264-4401","http://hdl.handle.net/10985/16675","en","Centre de Angers","Emerald",,"Post-print",,,"Sciences de l'ingénieur","Simulations of two-dimensional steady isothermal and non-isothermal steady flows with slip for a viscoelastic memory-integral fluid","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"8","Engineering Computations",,,"2318-2342","Oui",,,"32","true","newSubmission","aut||aut||aut","2019-09-12T11:39:05Z",,"hal-02284994","accept","true",,"1","crossref"
"b86d727c-2e00-47ad-9d31-5d310be06547","10985/191||10985/13599",,"IBÁÑEZ PINILLO, Rubén||AMMAR, Amine||CUETO, Elias||HUERTA, Antonio||DUVAL, Jean-Louis||CHINESTA, Francisco","2020","2020","2019",,,"Solutions of partial differential equations could exhibit a multiscale behavior. Standard discretization techniques are constraints to mesh up to the finest scale to predict accurately the response of the system. The proposed methodology is based on the standard proper generalized decomposition rationale; thus, the PDE is transformed into a nonlinear system that iterates between microscale and macroscale states, where the time coordinate could be viewed as a 2D time, representing the microtime and macrotime scales. The macroscale effects are taken into account because of an FEM-based macrodiscretization, whereas the microscale effects are handled with unidimensional parent spaces that are replicated throughout the domain. The proposed methodology can be seen as an alternative route to circumvent prohibitive meshes arising from the necessity of capturing fine-scale behaviors.","The Spanish Ministry of Economy and Competitiveness through grant DPI2015-72365-EXP, and by the Regional Government of Aragon and the European Social Fund (research group T24 17R).","10.1002/nme.6154","1097-0207","0029-5981","http://hdl.handle.net/10985/18456","en","Centre de Paris","Wiley","This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement 675919.","Post-print",,"partition of unity - proper generalized decomposition - time multiscale","Sciences de l'ingénieur: Matériaux","Multiscale proper generalized decomposition based on the partition of unity","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"6","International Journal for Numerical Methods in Engineering",,"10985/13599","727-747","Oui",,,"120","true","newSubmission","aut||aut||aut||aut||aut||aut","2020-04-17T08:32:11Z",,"hal-02545484","accept","true",,"1",
"9d8390bc-33a8-48bb-a6e3-cfad869ce06b","10985/191||10985/13599",,"AMMAR, Amine||CHINESTA, Francisco","2020","2020","2019",,,"The present work aims at performing a molecular dynamics modeling of suspensions composed of flexible linear molecules. Molecules are represented by a series of connected beads, whose dynamics is governed by three potentials: the extension potential affecting the elongation of segments connecting consecutive beads, the one governing the molecule bending and finally the Lennard-Jones describing the interaction of non-consecutive beads. A population of non-interacting molecules is simulated in elongation and shear flows for different flow and molecule parameters. The flow-induced conformation is analyzed in the different considered situations. Finally a model for predicting the evolution of the population conformation will be obtained by using deep-learning.",,"10.1016/j.crme.2019.11.001",,"1631-0721","http://hdl.handle.net/10985/18396","en","Centre de Paris","Elsevier Masson",,"Post-print",,"Deep-learning - Direct numerical simulation - Flexible molecules - Molecular dynamics - Suspension","Sciences de l'ingénieur: Matériaux","Direct numerical simulation of flexible molecules and data-driven molecular conformation","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"11","Comptes Rendus Mécanique",,"10985/13599||10985/13599||10985/13599||10985/13599","743-753","Oui",,,"347","true","newSubmission","aut||aut","2020-04-09T09:52:19Z",,"hal-02538193","accept","true",,"1",
"00466cf2-c954-4e43-8c79-2125505541f9","10985/191||10985/13599",,"KAZEMZADEH-PARSI, Mohammad Javad||AMMAR, Amine||DUVAL, Jean-Louis||CHINESTA, Francisco","2021","2021","2021",,,"Space separation within the Proper Generalized Decomposition—PGD—rationale allows solving high dimensional problems as a sequence of lower dimensional ones. In our former works, different geometrical transformations were proposed for addressing complex shapes and spatially non-separable domains. Efficient implementation of separated representations needs expressing the domain as a product of characteristic functions involving the different space coordinates. In the case of complex shapes, more sophisticated geometrical transformations are needed to map the complex physical domain into a regular one where computations are performed. This paper aims at proposing a very efficient route for accomplishing such space separation. A NURBS-based geometry representation, usual in computer aided design—CAD—, is retained and combined with a fully separated representation for allying efficiency (ensured by the fully separated representations) and generality (by addressing complex geometries). Some numerical examples are considered to prove the potential of the proposed methodology.",,"10.1186/s40323-021-00208-2",,"2213-7467","http://hdl.handle.net/10985/21175","en","Centre de Angers||Centre de Paris",,,"Post-print","Pas de Licence CC","Applied Mathematics||Computer Science Applications||Engineering (miscellaneous)||Modelling and Simulation||Space separated representation||Complex geometries||PGD||NURBS","Sciences de l'ingénieur","Enhanced parametric shape descriptions in PGD-based space separated representations","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"1","Advanced Modeling and Simulation in Engineering Sciences",,"10985/13599",,"Oui",,,"8","true","newSubmission","aut||aut||aut||aut","2021-11-10T13:49:52Z",,"hal-03424406","accept","true",,"1","crossref"
"2a441101-62b0-4431-a98f-171c6155acc3","10985/13599",,"BOUCINHA, Lucas||GRAVOUIL, Anthony||AMMAR, Amine","2014","2014","2013","2014",,"In this paper, we investigate ability of proper generalized decomposition (PGD) to solve transient elastodynamic models in space–time domain. Classical methods use time integration schemes and an incremental resolution process. We propose here to use standard time integration methods in a non-incremental strategy. As a result, PGD gives a separated representation of the space–time solution as a sum of tensorial products of space and time vectors, that we interpret as space–time modes. Recent time integration schemes are based on multi-field formulations. In this case, separated representation can be constructed using state vectors in space and same vectors in time. However, we have experienced bad convergence order using this decomposition. Furthermore, temporal approximation must be the same for all fields. Thus, we propose an extension of classical separated representation for multi-field problems. This multi-field PGD (MF-PGD) uses space and time vectors that are different for each field. Calculation of decomposition is done using a monolithic approach in space and time, potentially allowing the use of different approximations in space and time. Finally, several simulations are performed with the transient elastodynamic problem with one dimension in space. Different approximations in time are investigated: Newmark scheme, single field time discontinuous Galerkin method and two fields time continuous and discontinuous Galerkin methods.","Agence Nationale de la Recherche Française (SIMDREAM-2010)","10.1016/j.cma.2012.11.003",,"0045-7825","http://hdl.handle.net/10985/8461","en_US","Centre de Angers","Elsevier",,"Post-print",,"Model reduction||Elastodynamic||Singular value decomposition (SVD)||Proper generalized decomposition (PGD)||Multi-field proper generalized decomposition (MF-PGD)||Tensorial formalism","Sciences de l'ingénieur: Mécanique","Space–time proper generalized decompositions for the resolution of transient elastodynamic models","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Computer Methods in Applied Mechanics and Engineering",,,"67-88",,,,"255",,,"aut||aut||aut",,,"hal-01061196","accept","updateMetadata",,"1",
"cfb5b077-55c2-4d26-9fb9-3c818669f931","10985/13599||10985/191",,"PASQUALE, Angelo||AMMAR, Amine||FALCÓ, Antonio||PEROTTO, Simona||CUETO, Elías||DUVAL, Jean-Louis||CHINESTA, Francisco","2023","2023","2021",,,"Solutions of partial differential equations can exhibit multiple time scales. Standard discretization techniques are constrained to capture the finest scale to accurately predict the response of the system. In this paper, we provide an alternative route to circumvent prohibitive meshes arising from the necessity of capturing fine-scale behaviors. The proposed methodology is based on a time-separated representation within the standard Proper Generalized Decomposition, where the time coordinate is transformed into a multi-dimensional time through new separated coordinates, each representing one scale, while continuity is ensured in the scale coupling. For instance, when considering two different time scales, the governing Partial Differential Equation is commuted into a nonlinear system that iterates between the so-called microtime and macrotime, so that the time coordinate can be viewed as a 2D time. The macroscale effects are taken into account by means of a finite element-based macro-discretization, whereas the microscale effects are handled with unidimensional parent spaces that are replicated throughout the time domain. The resulting separated representation allows us a very fine time discretization without impacting the computational efficiency. The proposed formulation is explored and numerically verified on thermal and elastodynamic problems.",,"10.1186/s40323-021-00211-7",,"2213-7467","http://hdl.handle.net/10985/23265","en","Centre de Angers","Springer Science and Business Media LLC",,"Version éditeur","Pas de Licence CC","Applied Mathematics||Computer Science Applications||Engineering (miscellaneous)||Modeling and Simulation","Sciences de l'ingénieur","A separated representation involving multiple time scales within the Proper Generalized Decomposition framework","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"1","Advanced Modeling and Simulation in Engineering Sciences",,"10985/191",,"Oui",,,"8","true","newSubmission","aut||aut||aut||aut||aut||aut||aut","2023-02-01T13:43:26Z",,"hal-03501301","accept","true",,"1","crossref"
"03469d23-c98b-4200-8b1a-bee378583825","10985/13599||10985/191",,"AMMAR, Amine||CHINESTA, Francisco||VALETTE, Rudy","2023",,"2022",,,"Characterizing complex material consists in establishing the relationship between flow rheology during forming processes and the induced micro-structural state that affects directly the final mechanical properties of the formed parts [...]",,"10.3390/e24060782",,"1099-4300","http://hdl.handle.net/10985/23264","en","Centre de Angers||Centre de Paris","MDPI AG",,"Version éditeur","Pas de Licence CC","General Physics and Astronomy||Engineering sciences||Mechanical engineering||Mechanics||Fluids mechanics||Condensed matter||Soft condensed matter","Sciences de l'ingénieur||Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Introduction for the special Issue: statistical fluid dynamics","Article dans une revue avec comité de lecture","Internationale",,,,,"2022-12-01","2022-12-01",,"crossref",,"6","Entropy",,"10985/191","782","Oui",,,"24","true",,"aut||aut||aut",,,,"unsent",,,,"crossref"
"bff6375f-6767-45fa-b42b-78adb5b971ef","10985/13599||10985/191",,"SAAD, Sandra||SINHA, Alankar||CRUZ, Camilo||AMMAR, Amine||REGNIER, Gilles","2023",,"2022",,,"The computational cost of high-fidelity injection molding simulations has been growing in the past years making it more and more challenging to use them for performing analyses such as optimizations or uncertainty quantification. Surrogate modeling offers a cheaper way to realize such studies and has been gaining attention in the field of injection molding simulation. In this work, we propose to compare three surrogate modeling techniques along with two design of experiment methods in their ability to predict the pressure signal at a surface node in a Moldflow simulation by varying process and modeling parameters. A Sobol sensitivity analysis is performed to study the contribution of the varied parameters on the pressure results. In addition, one of the generated models is used along with experimental pressure sensor data to improve the pressure estimation by calibrating the heat transfer coefficients during filling and packing as well as the pressure-dependency coefficient in the Cross-WLF viscosity model. This resulted in major improvements of the pressure predictions for all 27 considered cases in comparison to using the default heat transfer coefficients and viscosity model parameter.",,"10.1007/s12289-022-01717-0",,"1960-6206||1960-6214","http://hdl.handle.net/10985/23263","en","Centre de Angers||Centre de Paris","Springer Nature",,"Post-print","Pas de Licence CC","General Materials Science||Surrogate modeling||Injection molding||Process simulation||Parameter optimization||Sensitivity analysis","Sciences de l'ingénieur","Towards an accurate pressure estimation in injection molding simulation using surrogate modeling","Article dans une revue avec comité de lecture","Internationale",,,,,"2023-04-04","2023-04-04",,"crossref",,"6","International Journal of Material Forming",,"10985/191","2-19","Oui",,,"15","true","newSubmission","aut||aut||aut||aut||aut","2023-02-01T09:04:32Z",,"hal-03967036","accept","true",,"1","crossref"
"72f11379-074b-4377-9dd7-0b423ccbdd7a","10985/13599||10985/191",,"TORREGROSA, Sergio||CHAMPANEY, Victor||AMMAR, Amine||HERBERT, Vincent||CHINESTA, Francisco","2023",,"2022",,,"Nowadays data is acquiring an indisputable importance in every field including engineering. In the past, experimental data was used to calibrate state-of-the art models. Once the model was optimally calibrated, numerical simulations were run. However, data can offer much more, playing a more important role than calibration or statistical analysis in the modeling/simulation process. Indeed, today data is gathered and used to train models able to replace complex engineering systems. The more and better the training data, the more accurate the model is. However, in engineering experimental data use to be the best data but also the most expensive in time and computing effort. Therefore, numerical simulations, cheaper and faster, are used instead but, even if they are closed to reality, they always present an error related to the ignorance of the engineer over the complex real system. It seems thus coherent to take advantage of each approach. This leads to the “hybrid twin” rationale. On the one hand, numerical simulations are computed as primary data source, assuming their inherent error. On the other hand, some experimental data is gathered to train a machine learning correction model which fills the prediction-measurement gap. However, learning this ignorance gap becomes difficult in some fields such as fluids dynamics, where a regression over the localized solutions can lead to non physical interpolated solutions. Therefore, the “hybrid twin” methodology proposed in this article relies on Optimal Transport theory, which provides a mathematical framework to measure distances between general objects and a completely different interpolation approach between functions.",,"10.1016/j.camwa.2022.09.026",,"0898-1221","http://hdl.handle.net/10985/23262","en","Centre de Angers||Centre de Paris","Elsevier BV",,"Post-print","Pas de Licence CC","Computational Mathematics||Computational Theory and Mathematics||Modeling and Simulation||Hybrid twin||Artificial intelligence||Optimal transport||Model order reduction||Fluid dynamics","Sciences de l'ingénieur||Informatique: Intelligence artificielle","Hybrid twins based on optimal transport","Article dans une revue avec comité de lecture","Internationale",,,,,"2023-04-05","2023-04-05",,"crossref",,,"Computers  & Mathematics with Applications",,"10985/191","12-24","Oui",,,"127","true","newSubmission","aut||aut||aut||aut||aut","2023-02-01T08:36:27Z",,"hal-03966991","accept","true",,"1","crossref"
"80c1f660-ff90-42a2-a558-7b9c58673174","10985/13599",,"BAKAK, Abderrahim||LOTFI, Mohamed||HEYD, Rodolphe||AMMAR, Amine||KOUMINA, Abdelaziz","2023","2023","2021",,,"The dynamic viscosity and rheological properties of two different non-aqueous graphene nano-plates-based nanofluids are experimentally investigated in this paper, focusing on the effects of solid volume fraction and shear rate. For each nanofluid, four solid volume fractions have been considered ranging from 0.1% to 1%. The rheological characterization of the suspensions was performed at 20°C, with shear rates ranging from 10⁻¹ s⁻¹  to 10³s⁻¹, using a cone-plate rheometer. The Carreau–Yasuda model has been successfully applied to fit most of the rheological measurements. Although it is very common to observe an increase of the viscosity with the solid volume fraction, we still found here that the addition of nanoparticles produces lubrication effects in some cases. Such a result could be very helpful in the domain of heat extraction applications. The dependence of dynamic viscosity with graphene volume fraction was analyzed using the model of Vallejo et al.",,"10.3390/e23080979",,"1099-4300","http://hdl.handle.net/10985/23267","en","Centre de Angers","MDPI AG",,"Version éditeur","Pas de Licence CC","General Physics and Astronomy","Sciences de l'ingénieur","Viscosity and Rheological Properties of Graphene Nanopowders Nanofluids","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"8","Entropy",,,"979","Oui",,,"23","true","newSubmission","aut||aut||aut||aut||aut","2023-02-01T14:58:16Z",,"hal-03968016","accept","true",,"1","crossref"
"9f8025d0-6cb4-43e7-83bb-c8b347423bcd","10985/13599",,"DAHER, Ali||AMMAR, Amine||HIJAZI, Abbas||BENYAHIA, Lazhar","2023","2023","2021",,,"The effect of shear flow on spherical nanoparticles (NPs) migration near a liquid–liquid interface is studied by numerical simulation. We have implemented a compact model through which we use the diffuse interface method for modeling the two fluids and the molecular dynamics method for the simulation of the motion of NPs. Two different cases regarding the state of the two fluids when introducing the NPs are investigated. First, we introduce the NPs randomly into the medium of the two immiscible liquids that are already separated, and the interface is formed between them. For this case, it is shown that before applying any shear flow, 30% of NPs are driven to the interface under the effect of the drag force resulting from the composition gradient between the two fluids at the interface. However, this percentage is increased to reach 66% under the effect of shear defined by a Péclet number Pe = 0.316. In this study, different shear rates are investigated in addition to different shearing times, and we show that both factors have a crucial effect regarding the migration of the NPs toward the interfacial region. In particular, a small shear rate applied for a long time will have approximately the same effect as a greater shear rate applied for a shorter time. In the second studied case, we introduce the NPs into the mixture of two fluids that are already mixed and before phase separation so that the NPs are introduced into the homogenous medium of the two fluids. For this case, we show that in the absence of shear, almost all NPs migrate to the interface during phase separation, whereas shearing has a negative result, mainly because it affects the phase separation.",,"10.3390/e23091143",,"1099-4300","http://hdl.handle.net/10985/23266","en","Centre de Angers","MDPI AG",,"Version éditeur","Pas de Licence CC","General Physics and Astronomy","Sciences de l'ingénieur||Sciences de l'ingénieur","Effect of Shear Flow on Nanoparticles Migration near Liquid Interfaces","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"9","Entropy",,,"1143","Oui",,,"23","true","newSubmission","aut||aut||aut||aut","2023-02-01T14:37:09Z",,"hal-03967919","accept","true",,"1","crossref"
"4fbd93ad-0994-44f1-a5c8-10c9b0203979","10985/13599",,"KRIAA, Yosra||AMMAR, Amine||ZOUARI, Bassem","2023","2023","2020",,,"Numerical simulations and parametric studies of notched rectangular specimens subjected to dynamic tensile loads were performed. The simulations were based on two-dimensional finite element analysis to predict the brittle fracture path using the phase-field approach. The parametric studies investigated the influence of geometric parameters and the loading speed on crack path propagation. An empirical model based on the sparse proper generalized decomposition learning technique was created to predict the crack path. This model provides a quick prediction of the global behavior of the crack path circumventing the CPU cost of the full finite element method simulation.",,"10.5802/crmeca.52",,"1873-7234","http://hdl.handle.net/10985/23268","en","Centre de Angers","Cellule MathDoc/CEDRAM",,"Version éditeur","Pas de Licence CC","Mechanics of Materials||General Materials Science","Sciences de l'ingénieur","Data-driven model based on the simulation of cracking process in brittle material using the phase-field method in application","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"8-9","Comptes Rendus. Mécanique",,,"729-744","Oui",,,"348","true","newSubmission","aut||aut||aut","2023-02-01T15:06:42Z",,"hal-03968102","accept","true",,"1","crossref"
"a9c17e3c-dec5-4864-bbfb-df18cc203e57","10985/13599",,"JALOULI, Zahra||CAILLAUD, Aude||ARTOZOUL, Julien||AMMAR, Amine||EL-ABIDI, Ahmed||FETTAH, Ahmed","2023","2023","2021",,,"Most commercial softwares simulating casting process use a scalar field to quantify the shrinkage on final parts. The repartition of this scalar is used to localize shrinkage in the part. In this work, the objective is to use a new approach to predict morphological information about size and shape of shrinkage: the phase field method. This method is based on a parameter order defining the alternating zones metal/gas. Starting with a uniform unit value of this scalar, the phase field equation is modified with a nucleation process predicting the growth of the air phase into the metal one still liquid. The coupling with the Navier-Stokes equation brings up some interesting non-dimensional parameters that affect shrinkage morphology. This is what we have tried to analyse after proposing the modified phase fields formalism. Even if we are not yet in the predictive stage, we present in the end of this paper a numerical/experimental comparison showing the potentiality of the developed approach.",,"10.1007/s12289-020-01602-8",,"1960-6206||1960-6214","http://hdl.handle.net/10985/23269","en","Centre de Angers","Springer Science and Business Media LLC",,"Post-print","Pas de Licence CC","General Materials Science","Sciences de l'ingénieur","Modelling of shrinkage formation in casting by the phase field method","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"5","International Journal of Material Forming",,,"885-899","Oui",,,"14","true","newSubmission","aut||aut||aut||aut||aut||aut","2023-02-02T09:13:43Z",,"hal-03969160","accept","true",,"1","crossref"
"e199710d-b0c6-47f4-bc8f-8f6dddd9ad7e","10985/13599",,"EL JIRARI, PhD, Dr Imane||EL BAROUDI, Adil||AMMAR, Amine","2023","2023","2021",,,"A promising advance of bioengineering consists in the development of micro-nanoparticles as drug delivery vehicles injected intravenously or intraarterialy for targeted treatment. Pro cient functioning of drug carries is conditioned by a reliable prediction of pharma- cokinetics in human as well as their dynamical behavior once injected in blood stream. In this study we aim to provide a reliable numerical prediction of dynamical behavior of microparticles in human arteriole focusing on the crucial mechanism of lateral migration. The dynamical response of the microparticle upon blood  flow and arteriolar distensibility is investigated by varying main controlling parameters: viscosity ratio, con nement and capillary number. The influence of the hyperelastic arteriolar wall is highlighted through comparison with an in nitely rigid arteriolar wall. The hydrodynamic interaction in a microparticle train is examined. Fluid-structure interaction is solved by the Arbitrary Lagrangian Eulerian method using the COMSOL Multiphysics software.",,"10.1142/S0219519421500627",,"1793-6810","http://hdl.handle.net/10985/23162","en","Centre de Angers","World Scientific Publishing",,"Post-print","Pas de Licence CC",,"Sciences de l'ingénieur: Mécanique||Sciences de l'ingénieur: Mécanique","Effect of arteriolar distensibility on the lateral migration of liquid-filled microparticles flowing in a human arteriole","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"8","Journal of Mechanics in Medicine and Biology",,,,"Oui",,,"21","true","newSubmission","aut||aut||aut","2023-01-23T09:36:53Z",,"hal-03951524","accept","true",,"1",
"a20cd100-1919-43bf-9be6-9243723c6f07","10985/13599",,"EL JIRARI, PhD, Dr Imane||EL BAROUDI, Adil||AMMAR, Amine","2023","2023","2021",,,"The study of artificial microparticles (capsules and vesicles) has gained a growing interest with the emergence of bioengineering. One of their promoting applications is their use as therapeutic vectors for drug delivery, when capsules and vesicles release their capacity in a targeted environment. The dynamic behavior of capsules and vesicles in confined or unbounded flows was widely studied in the literature and their mechanical response was truthfully described using constitutive laws with good agreement with experiences. However, in a context of biological application, to our knowledge, none of published studies investigating the mechanical response of deformable microparticle took into account the real physiological conditions: the rheological properties of blood such as carrying fluid and the mechanical properties of blood vessels. In this paper, we consider a hyperelastic microparticle suspended in human arteriole. We investigate the deformation of the microparticle resulting from its interaction with blood flow and the arteriolar wall using various capillary numbers and respecting physiological properties of blood and arterial wall. The influence of the blood viscosity model (Newtonian vs shear-thinning) is investigated and a comparison with a rigid microchannel and a muscle-embedded arteriole are carried out. The fluid structure interaction (FSI) problem is solved using Arbitrary Lagrangian Eulerian (ALE) method. Our simulations have revealed that the arteriolar wall distensibility deeply influences both the deformation and velocity of the microparticle: the deformation strongly increases while the velocity decreases in comparison to an infinitely rigid wall. In the context of therapeutic procedure of targeted drug-delivery, a particular attention should be addressed to these observations, in particular for their implication in the burst mechanism.",,"10.1115/1.4049955",,"1528-8951","http://hdl.handle.net/10985/23163","en","Centre de Angers","ASME",,"Post-print","Pas de Licence CC",,"Sciences de l'ingénieur: Mécanique","Numerical investigation of the dynamical behavior of a fluid-filled microparticle suspended in human arteriole","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Journal of Biomechanical Engineering",,,,"Oui",,,,"true","newSubmission","aut||aut||aut","2023-01-23T10:08:15Z",,"hal-03951641","accept","true",,"1",
"288335e6-c440-428c-a2be-dfe8f2f6e1ce","10985/13599||10985/191",,"KAZEMZADEH-PARSI, Mohammad-Javad||CHINESTA, Francisco||AMMAR, Amine","2023","2023","2021",,,"The use of mesh-based numerical methods for a 3D elasticity solution of thick plates involves high computational costs. This particularly limits parametric studies and material distribution design problems because they need a large number of independent simulations to evaluate the effects of material distribution and optimization. In this context, in the current work, the Proper Generalized Decomposition (PGD) technique is adopted to overcome this difficulty and solve the 3D elasticity problems in a high-dimensional parametric space. PGD is an a priori model order reduction technique that reduces the solution of 3D partial differential equations into a set of 1D ordinary differential equations, which can be solved easily. Moreover, PGD makes it possible to perform parametric solutions in a unified and efficient manner. In the present work, some examples of a parametric elasticity solution and material distribution design of multi-directional FGM composite thick plates are presented after some validation case studies to show the applicability of PGD in such problems.",,"10.3390/ma14216660",,"1996-1944","http://hdl.handle.net/10985/23283","en","Centre de Angers","MDPI AG",,"Version éditeur","Pas de Licence CC","General Materials Science","Sciences de l'ingénieur","Proper Generalized Decomposition for Parametric Study and Material Distribution Design of Multi-Directional Functionally Graded Plates Based on 3D Elasticity Solution","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"21","Materials",,"10985/191","6660","Oui",,,"14","true","newSubmission","aut||aut||aut","2023-02-06T09:07:07Z",,"hal-03974665","accept","true",,"1","crossref"
"e436844b-8188-4830-89d4-ed630e709256","10985/13599",,"DUMON, Antoine||ALLERY, Cyrille||AMMAR, Amine","2015","2015","2013","2015",,"The aim of this study is to apply proper generalized decomposition (PGD) to solve mixed-convection problems with and without mass transport in a two dimensional lid-driven cavity. PGD is an iterative reduced order model approach which consists of solving a partial differential equation while seeking the solution in separated form. Comparisons with results in the literature and with results from a standard solver are make. For the case of a mixed-convection problem without mass transfer, three Richardson numbers are considered, Ri=0.1, Ri=1, and Ri=10. In this case, PGD is seven times faster than the standard solver with Ri=10 with a similar accuracy. For the case with mass transfer, simulations are done with different Lewis numbers, Le=5, Le=25, and Le=50, and with different value of the ratio N between the solutal and the thermal Grashoff numbers. In this case, too, PGD is ten times faster than the standard solver.",,"10.1080/10407790.2012.724991","1521-0626","1040-7790","http://hdl.handle.net/10985/10267","en","Centre de Angers","Taylor & Francis",,"Post-print",,"Simulation||Heat transport||Mass transport||Proper generalized decomposition||PGD","Sciences de l'ingénieur: Mécanique: Mécanique des fluides||Sciences de l'ingénieur: Mécanique: Mécanique des structures","Simulation of Heat and Mass Transport in a Square Lid-Driven Cavity with Proper Generalized Decomposition (PGD)","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"1","Numerical Heat Transfer, Part B Fundamentals",,,"18-43",,,,"63",,,"aut||aut||aut",,,"hal-01207113","accept",,,"1",
"e6a107fc-aa75-4a6b-8aae-06d480ae8b90","10985/13599",,"AMMAR, Amine","2016","2017","2016","2016",,"The Langevin function is defined by L (x ) = coth (x ) −1 /x . Its inverse is useful for many applications and especially for polymer science. As the inverse exact expression has no analytic representation, many ap- proximations have been established. The most famous approximation is the one traditionally used for the finitely extensible non-linear elastic (FENE) dumbbell model in which the inverse is approximated by L −1 (y ) = 3 y/ (1 −y 2 ) . Recently Martin Kröger has published a paper entitled ‘Simple, admissible and accurate approximations of the inverse Langevin and Brillouin functions, relevant for strong polymer de- formation and flows’ (Kröger, 2015) in which he proposed approximations with very reduced error in relation to the numeric inverse of the Langevin function. The question we aim to analyze in this short communication is: when one uses the traditional approximation rather than the more accurate one pro- posed by Kröger is that really significant regarding the value of the probability distribution function (PDF) in the frame work of a kinetic theory simulation? If yes when we move to the upper scale by evaluating the value of the stress, can we observe a significant difference? By making some simple 1D simulations in homogeneous extensional flow it is demonstrated in this short communication that the PDF prediction within kinetic theory framework as well as the macroscopic stress value are both affected by the quality of the approximation.",,"10.1016/j.jnnfm.2016.02.008",,"0377-0257","http://hdl.handle.net/10985/11141","en","Centre de Angers","Elsevier",,"Post-print",,"polymer kinetic theory||Langevin function||inverse approximation","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Effect of the inverse Langevin approximation on the solution of the Fokker-Planck equation of non-linear dilute polymer","Article dans une revue avec comité de lecture","Internationale",,,,,,"2018-05-01",,,,"231","Journal of Non-Newtonian Fluid Mechanics",,,"1-5","Oui",,,,,,"aut",,,"hal-01361406","accept",,,"1",
"0e400193-db89-4bfc-ad01-c186550b52a8","10985/191||10985/13599",,"KAZEMZADEH-PARSI, Mohammad-Javad||AMMAR, Amine||CHINESTA, Francisco","2022","2022","2022",,,"A domain decomposition technique combined with an enhanced geometry mapping based on the use of NURBS is considered for solving parametrized models in complex geometries (non simply connected) within the so-called proper generalized decomposition (PGD) framework, enabling the expression of the solution in each subdomain in a fully separated form, involving both the space and the model parameters. NURBS allow a compact and powerful domain mapping into a fully separated reference geometry, while the PGD allows recovering an affine structure of the problem in the reference domain, facilitating the use of the standard PGD solver for computing the parametric solution in each subdomain first, and then by enforcing the interface transmission conditions, in the whole domain.",,"10.1186/s40323-022-00216-w",,"2213-7467","http://hdl.handle.net/10985/22202","en","Centre de Angers||Centre de Paris","Springer",,"Version éditeur","CC BY","Applied Mathematics||Computer Science Applications||Engineering (miscellaneous)||Modeling and Simulation||Complex geometry","Sciences de l'ingénieur","Domain decomposition involving subdomain separable space representations for solving parametric problems in complex geometries","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref||crossref",,,"Advanced Modeling and Simulation in Engineering Sciences",,"10985/13599","art. no. 2","Oui",,,"9","true","newSubmission","aut||aut||aut","2022-06-29T12:41:36Z",,"hal-03708814","accept","true",,"1","crossref"
"7d0690bc-d278-4de3-92bc-c023c2d1f30c","10985/13599",,"AGHIGHI, Mohammad Saeid||AMMAR, Amine||METIVIER, Christel||CHINESTA, Francisco","2015","2015","2015","2015",,"Purpose – The purpose of this paper is to focus on the advanced solution of the parametric non-linear model related to the Rayleigh-Benard laminar flow involved in the modeling of natural thermal convection. This flow is fully determined by the dimensionless Prandtl and Rayleigh numbers. Thus, if one could precompute (off-line) the model solution for any possible choice of these two parameters the analysis of many possible scenarios could be performed on-line and in real time. Design/methodology/approach – In this paper both parameters are introduced as model extracoordinates, and then the resulting multidimensional problem solved thanks to the space-parameters separated representation involved in the proper generalized decomposition (PGD) that allows circumventing the curse of dimensionality. Thus the parametric solution will be available fast and easily. Findings – Such parametric solution could be viewed as a sort of abacus, but despite its inherent interest such calculation is at present unaffordable for nowadays computing availabilities because one must solve too many problems and of course store all the solutions related to each choice of both parameters. Originality/value – Parametric solution of coupled models by using the PGD. Model reduction of complex coupled flow models. Analysis of Rayleigh-Bernard flows involving nanofluids.",,"10.1108/HFF-06-2014-0196",,"0961-5539","http://hdl.handle.net/10985/10242","en","Centre de Angers","Emerald",,"Post-print",,"Nanofluids||Model order reduction||Parametric solutions||PGD||Rayleigh-Benard model||Proper generalized decomposition","Informatique: Ingénierie assistée par ordinateur||Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Parametric solution of the Rayleigh-Benard convection model by using the PGD Application to nanofluids","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"6","International Journal of Numerical Methods for Heat and Fluid Flow",,,"1252-1281",,,,"25",,,"aut||aut||aut||aut",,,"hal-01206794","accept","updateMetadata",,"1",
"815f7ab4-e092-49ed-905e-5722ec3efb3a","10985/13599",,"GRMELA, Miroslav||AMMAR, Amine||CHINESTA, Francisco||MAITREJEAN, Guillaume","2015","2017","2014","2015",,"We extend the Maffettone–Minale model by including non-elliptical shapes of dispersed particles, a new family of internal forces controlling particle deformations, and particle–particle interactions. The last extension is made by transposing the way the chain-chain interactions are mathematically expressed in the reptation theory to suspensions. The particle–particle interactions are regarded as a confinement to cages formed by surrounding particles and by introducing a new dissipative motion (an analog of the reptation motion) inside the cages. Nonlinear responses to imposed shear and elongational flows are found to be in qualitative agreement with available experimental data.","One of the authors (M.G.) acknowledges the financial support provided by the Natural Sciences and Engineering Research Council of Canada.","10.1016/j.jnnfm.2014.07.005",,"0377-0257","http://hdl.handle.net/10985/9962","en","Centre de Angers","Elsevier",,"Post-print",,"Soft colloids||rheology of concentrated suspension||Generic","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","A mesoscopic rheological model of moderately concentrated colloids","Article dans une revue avec comité de lecture","Internationale",,,,,,"2 Years",,,,,"Journal of Non-Newtonian Fluid Mechanics",,,"1-12",,,,"212",,,"aut||aut||aut||aut","2020-02-04T09:58:50Z",,"hal-02465887","accept","true",,"1",
"2ca5f511-91b2-4869-8112-c35dc078a2d1","10985/13599",,"DUMON, Antoine||ALLERY, Cyrille||AMMAR, Amine","2014","2014","2011","2014",,"In this work, the PGD method will be considered for solving some problems of fluid mechanics by looking for the solution as a sum of tensor product functions. In the first stage, the equations of Stokes and Burgers will be solved. Then, we will solve the Navier–Stokes problem in the case of the lid-driven cavity for different Reynolds numbers (Re = 100, 1000 and 10,000). Finally, the PGD method will be compared to the standard resolution technique, both in terms of CPU time and accuracy.","Région Poitou-Charentes","10.1016/j.jcp.2010.11.010","1090-2716","0021-9991","http://hdl.handle.net/10985/8469","en_US","Centre de Angers","Elsevier",,"Post-print",,"Reduced order model||Proper generalized decomposition||Lid-driven cavity||Navier–Stokes equations","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Proper general decomposition (PGD) for the resolution of Navier–Stokes equations","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"4","Journal of Computational Physics",,,"1387-1407",,,,"230",,,"aut||aut||aut",,,"hal-01061383","accept",,,"1",
"87ab7707-65cb-409a-958e-5587d8becccb","10985/13599",,"BERGAMASCO, Luca||IZQUIERDO, Salvador||AMMAR, Amine","2014","2014","2013","2014",,"Micro–macro simulations of polymeric solutions rely on the coupling between macroscopic conservation equations for the fluid flow and stochastic differential equations for kinetic viscoelastic models at the microscopic scale. In the present work we introduce a novel micro–macro numerical approach, where the macroscopic equations are solved by a finite-volume method and the microscopic equation by a lattice-Boltzmann one. The kinetic model is given by molecular analogy with a finitely extensible non-linear elastic (FENE) dumbbell and is deterministically solved through an equivalent Fokker–Planck equation. The key features of the proposed approach are: (i) a proper scaling and coupling between the micro lattice-Boltzmann solution and the macro finite-volume one; (ii) a fast microscopic solver thanks to an implementation for Graphic Processing Unit (GPU) and the local adaptivity of the lattice-Boltzmann mesh; (iii) an operator-splitting algorithm for the convection of the macroscopic viscoelastic stresses instead of the whole probability density of the dumbbell configuration. This latter feature allows the application of the proposed method to non-homogeneous flow conditions with low memory-storage requirements. The model optimization is achieved through an extensive analysis of the lattice-Boltzmann solution, which finally provides control on the numerical error and on the computational time. The resulting micro–macro model is validated against the benchmark problem of a viscoelastic flow past a confined cylinder and the results obtained confirm the validity of the approach.",,"10.1016/j.jnnfm.2013.07.004",,"0377-0257","http://hdl.handle.net/10985/8462","en_US","Centre de Angers","Elsevier",,"Post-print",,"Multi-scale||Finite volume method||Lattice Boltzmann method||FENE kinetic model||GPU computing","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Direct numerical simulation of complex viscoelastic flows via fast lattice-Boltzmann solution of the Fokker–Planck equation","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Journal of Non-Newtonian Fluid Mechanics",,,"29-38",,,,"201",,,"aut||aut||aut",,,"hal-01061178","accept",,,"1",
"2efb4774-d236-48ca-9d6f-a4df6949b72a","10985/13599",,"LAMARI, Hajer||AMMAR, Amine||LEYGUE, Adrien||CHINESTA, Francisco","2014",,"2012","2014","http://dx.doi.org/10.1088/0965-0393/20/1/015007","The dynamics of phase transition in a binary mixture occurring during a quench is studied taking into account composition fluctuations by solving Langer’s equation in a domain composed of a certain number of micro-domains. The resulting Langer’s equation governing the evolution of the distribution function becomes multidimensional. Circumventing the curse of dimensionality the proper generalized decomposition is applied. The influence of the interaction parameter in the vicinity of the critical point is analyzed. First we address the case of a system composed of a single micro-domain in which phase transition occurs by a simple symmetry change. Next, we consider a system composed of two micro-domains in which phase transition occurs by phase separation, with special emphasis on the effect of the Landau free energy non-local term. Finally, some systems consisting of many micro-domains are considered.",,"10.1088/0965-0393/20/1/015007","1361-651X","0965-0393","http://hdl.handle.net/10985/8479","en_US","Centre de Angers","IOP Publishing",,"Post-print",,"Soft matter, liquids and polymers||Condensed matter: structural, mechanical & thermal","Sciences de l'ingénieur: Mécanique: Mécanique des matériaux","On the solution of the multidimensional Langer’s equation using the proper generalized decomposition method for modeling phase transitions","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"1","Modelling and Simulation in Materials Science and Engineering",,,"015007",,,,"20",,,"aut||aut||aut||aut",,,"hal-01061890","accept","updateMetadata",,"1",
"7125f59e-868c-4367-94f1-978cbd45e96b","10985/13599",,"DUMON, Antoine||ALLERY, Cyrille||AMMAR, Amine","2014","2014","2013","2014","http://dx.doi.org/10.1016/j.amc.2013.02.022","Proper Generalized Decomposition (PGD) is a method which consists in looking for the solution to a problem in a separate form. This approach has been increasingly used over the last few years to solve mathematical problems. The originality of this work consists in the association of PGD with a spectral collocation method to solve transfer equations as well as Navier–Stokes equations. In the first stage, the PGD method and its association with spectral discretization is detailed. This approach was tested for several problems: the Poisson equation, the Darcy problem, Navier–Stokes equations (the Taylor Green problem and the lid-driven cavity). In the Navier–Stokes problems, the coupling between velocity and pressure was performed using a fractional step scheme and a PN—PN-2 discretization. For all problems considered, the results from PGD simulations were compared with those obtained by a standard solver and/or with the results found in the literature. The simulations performed showed that PGD is as accurate as standard solvers. PGD preserves the spectral behavior of the errors in velocity and pressure when the time step or the space step decreases. Moreover, for a given number of discretization nodes, PGD is faster than the standard solvers.",,"10.1016/j.amc.2013.02.022",,"0096-3003","http://hdl.handle.net/10985/8487","en_US","Centre de Angers","Elsevier",,"Post-print",,"Reduced order model||Proper generalized decomposition||Incompressible flow||Spectral discretization","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Proper Generalized Decomposition method for incompressible Navier–Stokes equations with a spectral discretization","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"15","Applied Mathematics and Computation",,,"8145-8162",,,,"219",,,"aut",,,"hal-01062396","accept",,,"1",
"2d41f4a0-df14-45f4-93dd-59165f13c2db","10985/13599",,"AMMAR, Amine||CUETO, Elias||CHINESTA, Francisco","2014","2014","2012","2014",,"The numerical solution of the chemical master equation (CME) governing gene regulatory networks and cell signaling processes remains a challenging task owing to its complexity, exponentially growing with the number of species involved. Although most of the existing techniques rely on the use of Monte Carlo-like techniques, we present here a new technique based on the approximation of the unknown variable (the probability of having a particular chemical state) in terms of a finite sum of separable functions. In this framework, the complexity of the CME grows only linearly with the number of state space dimensions. This technique generalizes the so-called Hartree approximation, by using terms as needed in the finite sums decomposition for ensuring convergence. But noteworthy, the ease of the approximation allows for an easy treatment of unknown parameters (as is frequently the case when modeling gene regulatory networks, for instance). These unknown parameters can be considered as new space dimensions. In this way, the proposed method provides solutions for any value of the unknown parameters (within some interval of arbitrary size) in one execution of the program.","Spanish Ministry of Science and Innovation (CICTY-DPI2011-27778-C02-010)","10.1002/cnm.2476","2040-7947","2040-7939","http://hdl.handle.net/10985/8467","en_US","Centre de Angers","John Wiley and Sons",,"Post-print",,"Gene regulatory networks||Chemical master equation||Curse of dimensionality||Proper generalized decomposition","Sciences de l'ingénieur: Mécanique: Biomécanique","Reduction of the chemical master equation for gene regulatory networks using proper generalized decompositions","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"9","International Journal for Numerical Methods in Biomedical Engineering",,,"960-973",,,,"28",,,"aut||aut||aut",,,"hal-01061274","accept",,,"1",
"17f78f24-3b6b-4a6f-8afa-ba50828b49ac","10985/13599",,"GRMELA, Miroslav||MAITREJEAN, Guillaume||CHINESTA, Francisco||AMMAR, Amine","2015","2015","2013","2015",,"Smoluchowski kinetic equation governing the time evolution of the pair correlation function of rigid sphericalparticles suspended in a Newtonian fluid is extended to include particle migration. The extended kinetic equation takes into account three types of forces acting on the suspended particles: a direct force generated by an interparticle potential, hydrodynamic force mediated by the host fluid, and the Faxén-type forces bringing about the across-the-streamline particle migration. For suspensions subjected to externally imposed flows, the kinetic equation is solved numerically by the proper generalized decomposition method. The imposed flow investigated inthe numerical illustrations is the Poiseuille flow. Numerical solutions provide the morphology (the pair correlation function), the rheology (the stress tensor), and the particle migration.",,"10.1007/s00397-013-0705-7","1435-1528","0035-4511","http://hdl.handle.net/10985/10262","en","Centre de Angers","Springer Verlag",,"Post-print",,"Suspension||Particle||Colloids||Modeling||Rheology","Sciences de l'ingénieur: Mécanique: Mécanique des fluides||Sciences de l'ingénieur: Mécanique: Mécanique des structures","Kinetic theory of colloidal suspensions: morphology, rheology, and migration","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"6","Rheologica Acta",,,"557-577",,,,"52",,,"aut||aut||aut||aut",,,"hal-01207094","accept",,,"1",
"41eb6aa9-2993-4d06-b318-efe1f6fe1472","10985/13599",,"AMMAR, Amine||HUERTA, Antonio||CHINESTA, Francisco||CUETO, Elias||LEYGUE, Adrien","2015","2017","2014","2015",,"Optimization of manufacturing processes or structures involves the optimal choice of many parameters (process parameters, material parameters or geometrical parameters). Usual strategies proceed by defining a trial choice of those parameters and then solving the resulting model. Then, an appropriate cost function is evaluated and its optimality checked. While the optimum is not reached, the process parameters should be updated by using an appropriate optimization procedure, and then the model must be solved again for the updated process parameters. Thus, a direct numerical solution is needed for each choice of the process parameters, with the subsequent impact on the computing time. In this work we focus on shape optimization that involves the appropriate choice of some parameters defining the problem geometry. The main objective of this work is to describe an original approach for computing an off-line parametric solution. That is, a solution able to include information for different parameter values and also allowing to compute readily the sensitivities. The curse of dimensionality is circumvented by invoking the Proper Generalized Decomposition (PGD) introduced in former works, which is applied here to compute geometrically parametrized solutions.",,"10.1016/j.cma.2013.09.003",,"0045-7825","http://hdl.handle.net/10985/10244","en","Centre de Angers","Elsevier",,"Post-print",,"Model reduction||Proper Generalized Decomposition||Parametric models||Shape optimization","Informatique: Ingénierie assistée par ordinateur","Parametric solutions involving geometry: A step towards efficient shape optimization","Article dans une revue avec comité de lecture","Internationale",,,,,,"2 Years",,,,,"Computer Methods in Applied Mechanics and Engineering",,,"178-193",,,,"268",,,"aut||aut||aut||aut||aut","2020-02-20T15:21:55Z",,"hal-02486097","accept","true",,"1",
"0b3efa39-34d3-4447-9aeb-848c038f3a1e","10985/13599",,"AMMAR, Amine||MASOUMI, H.||AGHIGHI, Mohammad Saeid","2023",,"2022",,,"This study investigates the double-diffusive natural convection of the non-Newtonian Casson fluid in a square cavity based on the original viscoplastic stress model without simplification. Therefore, yield stress plays an essential role in understanding fluid behavior. The finite element approach provided a numerical solution to continuity, momentum, energy, and species governing equations. The governing parameters for this problem are Rayleigh number, Ra, yield number, Y, buoyancy ratio number, Nr, and Lewis number, Le. The influence of these parameters on heat and mass transfer, the morphology of yielded/unyielded regions, and fluid flow are thoroughly examined. The results show that unyielded regions increase at high Rayleigh numbers, despite the increase in buoyancy force and consequently increased heat and mass transfer. On the other hand, as the buoyancy ratio drops, the flow’s strength and heat and mass transmission diminish, leading to an increase in plug regions. Accordingly, the mechanisms influencing the growth of unyielded regions are complex and follow different patterns. However, the plug regions always grow with increasing Y. The results indicate that increasing the Lewis number (mass transfer) reduces the effect of the buoyancy ratio on flow, heat transfer, and the unyielded regions in every case. Quantitative analysis of the results indicates that, while buoyancy ratio affects heat and mass transfer almost equally, the Lewis number increases mass transfer up to three times the heat transfer. Meanwhile, changing the buoyancy ratio can increase the maximum yield stress to 400%, while changing the Lewis number has a maximum effect of 20%.",,"10.1016/j.ijmecsci.2022.107754",,"0020-7403","http://hdl.handle.net/10985/23261","en","Centre de Angers","Elsevier BV",,"Post-print","Pas de Licence CC","Mechanical Engineering||Mechanics of Materials||Condensed Matter Physics||General Materials Science||Civil and Structural Engineering||Double-diffusive convection||Non-newtonian fluid||Casson model||Yield stress||Finite element method","Sciences de l'ingénieur","Double-diffusive natural convection of Casson fluids in an enclosure","Article dans une revue avec comité de lecture","Internationale",,,,,"2023-03-16","2023-03-16",,"crossref",,,"International Journal of Mechanical Sciences",,,"107754","Oui",,,"236","true","newSubmission","aut","2023-02-01T08:09:44Z",,"hal-03966948","unsent","true",,"1","crossref"
"37b48b10-c030-4e70-8c65-c94f60ee29b8","10985/13599",,"CHINESTA, Francisco||MAGNIN, Morgan||ROUX, Olivier||AMMAR, Amine||CUETO, Elias","2015","2015","2015","2015",,"In this work, we begin by considering the qualitative modeling of biological regulatory systems using process hitting, from which we define its probabilistic counterpart by considering the chemical master equation within a kinetic theory framework. The last equation is efficiently solved by considering a separated representation within the proper generalized decomposition framework that allows circumventing the so-called curse of dimensionality. Finally, model parameters can be added as extra-coordinates in order to obtain a parametric solution of the model.","The authors acknowledge the contribution of Courtney Chancellor, who participated during one year to this research activity, and the first author, Francisco Chinesta, acknowledges the support of the Institute Universitaire de France (IUF). The work of Elias Cueto and Francisco Chinesta has been partially funded by the Spanish Ministry of Economy and Innovation through Grant Number DPI2014-51844-C2-1-R.","10.3390/e17041896",,"1099-4300","http://hdl.handle.net/10985/9964","en","Centre de Angers","MDPI",,"Post-print",,"chemical master equation||proper generalized decomposition (PGD)||qualitative modeling||process hitting||biological regulatory networks||statistical mechanics||kinetic theory","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Kinetic Theory Modeling and Efficient Numerical Simulation of Gene Regulatory Networks Based on Qualitative Descriptions","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"4","Entropy",,,"1896-1915",,,,"17",,,"aut||aut||aut||aut||aut",,,"hal-01195963","accept",,,"1",
"3569adc5-9e41-4493-ae93-7e91a419e013","10985/13599",,"CHACELLOR, Courtney||AMMAR, Amine||CHINESTA, Francisco||MAGNIN, Morgan||ROUX, Olivier","2015","2015","2013","2015",,"Modeling frameworks bring structure and analysis tools to large and non-intuitive systems but come with certain inherent assumptions and limitations, sometimes to an inhibitive extent. By building bridges in existing models, we can exploit the advantages of each, widening the range of analysis possible for larger, more detailed models of gene regulatory networks. In this paper, we create just such a link between Process Hitting [6,7,8], a recently introduced discrete framework, and the Chemical Master Equation in such a way that allows the application of powerful numerical techniques, namely Proper Generalized Decomposition [1,2,3], to overcome the curse of dimensionality. With these tools in hand, one can exploit the formal analysis of discrete models without sacrificing the ability to obtain a full space state solution, widening the scope of analysis and interpretation possible. As a demonstration of the utility of this methodology, we have applied it here to the p53-mdm2 network [4,5], a widely studied biological regulatory network.",,"10.1007/978-3-642-40708-6_5",,"0302-9743","http://hdl.handle.net/10985/10259","en","Centre de Angers","Springer",,"Post-print",,"Stochastic models||Chemical master equation||Process hitting||Proper generalized decomposition","Informatique: Ingénierie assistée par ordinateur","Linking Discrete and Stochastic Models: The Chemical Master Equation as a Bridge between Process Hitting and Proper Generalized Decomposition","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Lecture Notes in Computer Science",,,"50-63",,,,"8130",,,"aut||aut||aut||aut||aut",,,"hal-01207078","accept",,,"1",
"166ab24a-49ae-479f-a1cf-2dd5bb3dde3f","10985/13599",,"AGHIGHI, Mohammad Saeid||AMMAR, Amine||METIVIER, Christel||NORMANDIN, Magdeleine||CHINESTA, Francisco","2015","2015","2013","2015",,"This paper focuses on the non-incremental solution of transient coupled non-linear models, in particular the one related to the Rayleigh–Bénard flow problem that models natural thermal convection. For this purpose we are applying the so-called Proper Generalized Decomposition that proceeds by performing space-time separated representations of the different unknown fields involved by the flow model. This non-incremental solution strategy allows significant computational time savings and opens new perspectives for introducing some flow and/or fluid parameters as extra-coordinates.",,"10.1016/j.jnnfm.2012.11.007",,"0377-0257","http://hdl.handle.net/10985/10265","en","Centre de Angers","Elsevier",,"Post-print",,"Rayleigh–Bénard model||Power-law fluids||Model reduction||Non-incremental solution||Proper Generalized Decomposition||PGD","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Non-incremental transient solution of the Rayleigh–Bénard convection model by using the PGD","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Journal of Non-Newtonian Fluid Mechanics",,,"65-78",,,,"200",,,"aut||aut||aut||aut||aut",,,"hal-01207109","accept","updateMetadata",,"1",
"1cd37d0d-6ffc-4122-b567-5660360049df","10985/13599",,"MAITREJEAN, Guillaume||AMMAR, Amine||CHINESTA, Francisco||GRMELA, Miroslav","2014","2014","2012","2014",,"A direct modeling of colloidal suspensions consists of calculating trajectories of all suspended objects. Due to the large time computing and the large cost involved in such calculations, we consider in this paper another route. Colloidal suspensions are described on a mesoscopic level by a distribution function whose time evolution is governed by a Fokker–Plancklike equation. The difficulty encountered on this route is the high dimensionality of the space in which the distribution function is defined. A novel strategy is used to solve numerically the Fokker–Planck equation circumventing the curse of dimensionality issue. Rheological and morphological predictions of the model that includes both direct and hydrodynamic interactions are presented in different flows.",,"10.1007/s00397-011-0609-3","1532-7981","0735-0198","http://hdl.handle.net/10985/8466","en_US","Centre de Angers","Taylor & Francis (Routledge)",,"Post-print",,"Colloidal suspensions||Smoluchowski equation||Proper generalized decomposition","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Deterministic solution of the kinetic theory model of colloidal suspensions of structureless particles","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"6","Rhetoric Review",,,"527-543",,,,"51",,,"aut||aut||aut||aut",,,"hal-01061268","accept",,,"1",
"5294d31f-a939-427d-aec1-cf15114fd540","10985/13599",,"MAITREJEAN, Guillaume||AMMAR, Amine||CHINESTA, Francisco","2014","2014","2012","2014",,"The prediction of microstructure evolution during passive mixing is of major interest in order to qualify and quantify mixing devices as well as to predict the final morphology of the resulting blend. Direct numerical simulation fails because of the different characteristic lengths of the microstructure and the process itself. Micro-macro approaches could be a valuable alternative but the computational cost remains tremendous. For this reason many authors proposed the introduction of some microstructural variables able to qualify and quantify the mixing process at a mesoscale level. Some proposals considered only the effects induced by the flow kinematics, other introduced also the effects of shape relaxation due to the surface tension and coalescence. The most advanced integrate also the break-up process. However, the derivation of the evolution equations governing the evolution of such microstructural variables needs the introduction of some closure relations whose impact on the computed solution should be evaluated before applying it for simulating complex mixing flows. In this work we consider the Lee and Park’s model that considers the flow kinematics, the surface tension, the coalescence and the break-up mechanisms in the evolution of the area tensor. The accuracy of both a quadratic closure and an orthotropic relations will be analyzed in the first part of this work, and then the resulting closed model by using a quadratic closure will be used for simulating complex mixing flows.",,"10.1007/s12289-011-1037-8","1960-6214","1960-6206","http://hdl.handle.net/10985/8472","en_US","Centre de Angers","Springer Verlag",,"Post-print",,"Passive mixing||Microstructural approach||Area tensor||Closure relation","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Simulating microstructure evolution during passive mixing","Article dans une revue avec comité de lecture","Internationale",,,,,,,"verify",,,"1","International Journal of Material Forming",,,"73-81",,,,"5",,,"aut||aut||aut",,,"hal-01061439","accept","updateMetadata",,"1",
"ffc8dc02-a63b-49e3-b5b4-53b9af066fbb","10985/13599",,"BOUCINHA, Lucas||AMMAR, Amine||GRAVOUIL, Anthony||NOUY, Anthony","2014","2014","2014","2014",,"It is now well established that separated representations built with the help of proper generalized decomposition (PGD) can drastically reduce computational costs associated with solution of a wide variety of problems. However, it is still an open question to know if separated representations can be efficiently used to approximate solutions of hyperbolic evolution problems in space-time domain. In this paper, we numerically address this issue and concentrate on transient elastodynamic models. For such models, the operator associated with the space-time problem is non-symmetric and low-rank approximations are classically computed by minimizing the space-time residual in a natural L2 sense, yet leading to non optimal approximations in usual solution norms. Therefore, a new algorithm has been recently introduced by one of the authors and allows to find a quasi-optimal low-rank approximation a priori with respect to a target norm. We presently extend this new algorithm to multi-field models. The proposed algorithm is applied to elastodynamics formulated over space-time domain with the Time Discontinuous Galerkin method in displacement and velocity. Numerical examples demonstrate convergence of the proposed algorithm and comparisons are made with classical a posteriori and a priori approaches.","Agence Nationale de la Recherche Française (ANR-10-COSI-0006)","10.1016/j.cma.2014.01.019",,"0045-7825","http://hdl.handle.net/10985/8456","en_US","Centre de Angers","Elsevier",,"Post-print",,"Elastodynamics||Separation of variables||Proper orthogonal decomposition (POD)||Proper generalized decomposition (PGD)||Minimal residual||Multi-field","Sciences de l'ingénieur: Mécanique","Ideal minimal residual-based proper generalized decomposition for non-symmetric multi-field models – Application to transient elastodynamics in space-time domain","Article dans une revue avec comité de lecture","Internationale",,,,,,,"verify",,,,"Computer Methods in Applied Mechanics and Engineering",,,"56-76",,,,"273",,,"aut||aut||aut||aut",,,"hal-01060940","accept","updateMetadata",,"1",
"cc8f3690-b8fa-46a6-91ec-59b6e9445432","10985/13599",,"AMMAR, Amine||CHINESTA, Francisco||HEYD, Rodolphe","2017","2017","2016","2017",,"Enhancing thermal conductivity of simple fluids is of major interest in numerous applicative systems. One possibility of enhancing thermal properties consists of dispersing small conductive particles inside. However, in general, aggregation effects occur and then one must address systems composed of dispersed clusters composed of particles as well as the ones related to percolated networks. This papers analyzes the conductivity enhancement of different microstructures scaling from clusters dispersed into a simple matrix to the ones related to percolated networks exhibiting a fractal morphology.",,"10.3390/e19010019",,"1099-4300","http://hdl.handle.net/10985/11477","en","Centre de Angers","MDPI",,"Post-print",,"nanofluids||thermal homogenization||aggregation kinetics||percolation","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Thermal Conductivity of Suspension of Aggregating Nanometric Rods","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Entropy",,,"1-15","Oui",,,"19",,,"aut||aut||aut",,,"hal-01433016","accept",,,"1",
"fc9b7c26-9f95-4225-a48e-8be2a7e509a7","10985/13599",,"GHERISSI, Abderraouf||ABBASSI, Fethi||AMMAR, Amine||ZGHAL, Ali","2016","2017","2016","2016",,"This study proposes to simulate the deep drawing on carbon woven composites in order to reduce the manufacturing cost and waste of composite material during the stamping process, The multi-scale anisotropic approach of woven composite was used to develop a finite element model for simulating the orientation of fibers accurately and predicting the deformation of composite during mechanical tests and forming process. The proposed experimental investigation for bias test and hemispherical deep drawing process is investigated in the G1151 Interlock. The mechanical properties of carbon fiber have great influence on the deformation of carbon fiber composites. In this study, shear angle–displacement curves and shear load–shear angle curves were obtained from a bias extension test. Deep drawing experiments and simulation were conducted, and the shear load–displacement curves under different forming depths and shear angle–displacement curves were obtained. The results showed that the compression and shear between fibers bundles were the main deformation mechanism of carbon fiber woven composite, as well as the maximum shear angle for the composites with G1151 woven fiber was 58°. In addition, during the drawing process, it has been found that the forming depth has a significant influence on the drawing force. It increases rapidly with the increasing of forming depth. In this approach the suitable forming depth deep drawing of the sheet carbon fiber woven composite was approximately 45 mm.",,"10.1007/s10443-015-9468-x","1573-4897","0929-189X","http://hdl.handle.net/10985/11147","en","Centre de Angers","Springer Verlag (Germany)",,"Post-print",,"Carbon fiber woven||Bias test||Shear angle||Anisotropic approach||Finite elements modelling||Forming","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Numerical and Experimental Investigations on Deep Drawing of G1151 Carbon Fiber Woven Composites","Article dans une revue avec comité de lecture","Internationale",,,,,,"2017-06",,,,"3","Applied Composite Materials",,,"461-476","Oui",,,"23",,,"aut||aut||aut||aut",,"{""duplicate-entry"":{""hal-01361888"":{""doi"":""1.0"",""ensam"":""1.0""}}}","hal-01361888","accept","updateMetadata",,"1",
"3f1010f3-9e07-4982-80d8-04e9210702d2","10985/13599",,"AMMAR, Amine||CUETO, Elias||CHINESTA, Francisco","2015","2015","2012","2015",,"This work addresses the recurrent issue related to the existence of reduced bases related to the solution of parametric models defined in evolving domains. In this first part of the work, we address the case of decoupled kinematics, that is, models whose solution does not affect the domain in which they are defined. The chosen framework considers an updated Lagrangian description of the kinematics, solved by using natural neighbor Galerkin methods within a nonincremental space–time framework that can be generalized for addressing parametric models. Examples showing the performance and potentialities of the proposed methodology are included.","This is work is supported by the Spanish Ministry of Economy and Innovation (CICYT-DPI2011-27778-C02-01).","10.1002/nme.4413","1097-0207","0029-5981","http://hdl.handle.net/10985/10287","en","Centre de Angers","Wiley",,"Post-print",,"model reduction||proper generalized decomposition||large geometrical transformations||meshless methods||natural element method||parametric models","Informatique: Ingénierie assistée par ordinateur||Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Nonincremental proper generalized decomposition solution of parametric uncoupled models defined in evolving domains","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"8","International Journal for Numerical Methods in Engineering",,,"887-904",,,,"93",,,"aut||aut||aut",,,"hal-01207448","accept",,,"1",
"63099362-635a-4bfb-9558-05961bd24a81","10985/13599",,"CHINESTA, Francisco||LEYGUE, Adrien||BORDEU, Felipe||AGUADO, Jose Vicente||CUETO, Elias||GONZALEZ, David||AMMAR, Amine||HUERTA, Antonio||ALFARO, Icíar","2015","2016","2013","2015",,"In this paper we are addressing a new paradigm in the field of simulation-based engineering sciences (SBES) to face the challenges posed by current ICT technologies. Despite the impressive progress attained by simulation capabilities and techniques, some challenging problems remain today intractable. These problems, that are common to many branches of science and engineering, are of different nature. Among them, we can cite those related to high-dimensional problems, which do not admit mesh-based approaches due to the exponential increase of degrees of freedom. We developed in recent years a novel technique, called Proper Generalized Decomposition (PGD). It is based on the assumption of a separated form of the unknown field and it has demonstrated its capabilities in dealing with high-dimensional problems overcoming the strong limitations of classical approaches. But the main opportunity given by this technique is that it allows for a completely new approach for classic problems, not necessarily high dimensional. Many challenging problems can be efficiently cast into a multidimensional framework and this opens new possibilities to solve old and new problems with strategies not envisioned until now. For instance, parameters in a model can be set as additional extra-coordinates of the model. In a PGD framework, the resulting model is solved once for life, in order to obtain a general solution that includes all the solutions for every possible value of the parameters, that is, a sort of computational vademecum. Under this rationale, optimization of complex problems, uncertainty quantification, simulation-based control and real-time simulation are now at hand, even in highly complex scenarios, by combining an off-line stage in which the general PGD solution, the vademecum, is computed, and an on-line phase in which, even on deployed, handheld, platforms such as smartphones or tablets, real-time response is obtained as a result of our queries.",,"10.1007/s11831-013-9080-x","1886-1784","1134-3060","http://hdl.handle.net/10985/10241","en","Centre de Angers","Springer Verlag",,"Post-print",,"PGD||Computational Vademecum||Design||Optimization","Chimie: Polymères||Mathématique: Analyse numérique||Sciences de l'ingénieur: Mécanique: Mécanique des structures","PGD-Based Computational Vademecum for Efficient Design, Optimization and Control","Article dans une revue avec comité de lecture","Internationale",,,,,,"1 Year",,,,"1","Archives of Computational Methods in Engineering",,,"31-59",,,,"20",,,"aut",,,,"unsent",,,,
"a6082c03-9d95-4789-93a9-b4d52e41b216","10985/13599",,"GONZALEZ, David||BORDEU, Felipe||LEYGUE, Adrien||AMMAR, Amine||CUETO, Elias||CHINESTA, Francisco||ALFARO, Icíar","2015","2015","2014","2015",,"Simulation of all phenomena taking place in a surgical procedure is a formidable task that involves, when possible, the use of supercomputing facilities over long time periods. However, decision taking in the operating room needs for fast methods that provide an accurate response in real time. To this end, Model Order Reduction (MOR) techniques have emerged recently in the field of Computational Surgery to help alleviate this burden. In this paper, we review the basics of classical MOR and explain how a technique recently developed by the authors and coined as Proper Generalized Decomposition could make real-time feedback available with the use of simple devices like smartphones or tablets. Examples are given on the performance of the technique for problems at different scales of the surgical procedure, form gene regulatory networks to macroscopic soft tissue deformation and cutting.","This work has been partially supported by the Spanish Ministry of Economy and Competitiveness under grant number CICYT-DPI2011-27778-C02-01. This support is gratefully acknowledged. Prof. Chinesta is also supported by the Institut Universitaire de France.","10.1186/2194-3990-1-1","2194-3990",,"http://hdl.handle.net/10985/10254","en","Centre de Angers","Springer Verlag",,"Post-print",,"Model Order Reduction||Gene regulatory networks||Surgery simulation","Sciences du vivant: ingénierie bio-médicale","Real-time in silico experiments on gene regulatory networks and surgery simulation on handheld devices","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"1","Journal of Computational Surgery",,,"1-14",,,,"1",,,"aut",,,"hal-01206921","accept",,,"1",
"1cdb5dd4-51a4-43fb-baa9-2d17bee3d2a8","10985/13598||10985/13599",,"METOUI, Sondes||AMMAR, Amine||IORDANOFF, Ivan||DAU, Frédéric||PRULIERE, Etienne","2019","2019","2018",,,"The requirements for advanced numerical computations are very high when studying the multiscale behavior of heterogeneous structures such as composites. For the description of local phenomena taking place on the microscopic scale, the computation must involve a fine discretization of the structure. This condition leads to problems with a high number of degrees of freedom that lead to prohibitive computational costs when using classical numerical methods such as the finite element method (FEM). To overcome these problems, this paper presents a new domain decomposition method based on the proper generalized decomposition (PGD) to predict the behavior of periodic composite structures. Several numerical tests are presented. The PGD results are compared with those obtained using the classical finite element method. A very good agreement is observed.","Arts et Métiers ParisTech, Centre de Bordeaux, I2M-DuMAS","10.1016/j.matcom.2017.07.010",,"0378-4754","http://hdl.handle.net/10985/14855","en","Centre de Bordeaux-Talence||Centre de Angers","Elsevier",,"Post-print",,"Model reduction||Multiscale simulations||Proper Generalized Decomposition||Composite structures","Physique","A multiscale separated representation to compute the mechanical behavior of composites with periodic microstructure","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Mathematics and Computers in Simulation",,,"162-181","Oui",,,"144","true","newSubmission","aut","2019-09-13T14:22:38Z","<?xml version=""1.0"" encoding=""utf-8""?> <sword:error xmlns:sword=""http://purl.org/net/sword/error/"" xmlns=""http://www.w3.org/2005/Atom"" href=""http://purl.org/net/sword/error/ErrorBadRequest"">   <title>ERROR</title>   <updated>2019-09-02T15:54:07+02:00</updated>   <author>     <name>HAL SWORD API Server</name>   </author>   <source>     <generator uri=""https://api.archives-ouvertes.fr/sword"" version=""1.0"">hal@ccsd.cnrs.fr</generator>   </source>   <summary>Some parameters sent with the request were not understood</summary>   <sword:treatment>processing failed</sword:treatment>   <sword:verboseDescription>{""meta"":{""journal"":[""Invalid data""]}}</sword:verboseDescription>   <link rel=""alternate"" href=""https://api.archives-ouvertes.fr"" type=""text/html""/> </sword:error>||<?xml version=""1.0"" encoding=""utf-8""?> <sword:error xmlns:sword=""http://purl.org/net/sword/error/"" xmlns=""http://www.w3.org/2005/Atom"" href=""http://purl.org/net/sword/error/ErrorBadRequest"">   <title>ERROR</title>   <updated>2019-04-15T10:52:37+02:00</updated>   <author>     <name>HAL SWORD API Server</name>   </author>   <source>     <generator uri=""https://api.archives-ouvertes.fr/sword"" version=""1.0"">hal@ccsd.cnrs.fr</generator>   </source>   <summary>Some parameters sent with the request were not understood</summary>   <sword:treatment>processing failed</sword:treatment>   <sword:verboseDescription>{""meta"":{""journal"":[""Invalid data""]}}</sword:verboseDescription>   <link rel=""alternate"" href=""https://api.archives-ouvertes.fr"" type=""text/html""/> </sword:error>","hal-02286933","accept","true","newSubmission||newSubmission||newSubmission||newSubmission","1","crossref"
"c60d8269-b0c6-4669-be49-ee0db17e4eb8","10985/13599",,"AMMAR, Amine||MASOUMI, Hamed||LANJABI, A.||AGHIGHI, Mohammad Saeid","2023","2023","2020",,,".The objective of this paper is to clarify the role of sloping walls on convective heat transport in Rayleigh–Bénard convection within a trapezoidal enclosure filled with viscoplastic fluid. The rheology of the viscoplastic fluid has been modeled with Bingham fluid model. The system of coupled nonlinear differential equations was solved numerically by Galerkin's weighted residuals scheme of finite element method. The numerical experiments are carried out for a range of parameter values, namely, Rayleigh number (5.103 ≤ Ra ≤ 105), yield number (0 ≤ Y ≤ Yc), and sidewall inclination angle (ϕ = 0,  π/6,  π/4,  π/3) at a fixed Prandtl number (Pr = 500). Effects of the inclination angle on the flow and temperature fields are presented. The results reveal that inclination angle causes a multicellular flow and appears as the main parameter to govern heat transfer in the cavity. The heat transfer rate is found to increase with the increasing angle of the sloping wall for both Newtonian and yield stress fluids. On the other hand, the plug regions also found to increase with increasing φ, which is unusual but perhaps not unexpected behavior. In the yield stress fluids, the flow becomes motionless above a critical yield number Yc because the plug regions invade the whole cavity. The critical yield number Yc is also affected by the change of inclination angle and increases significantly with the increase of φ.",,"10.1016/j.ijmecsci.2020.105630",,"0020-7403","http://hdl.handle.net/10985/23273","en","Centre de Angers","Elsevier BV",,"Post-print","Pas de Licence CC","Mechanical Engineering||Mechanics of Materials||Condensed Matter Physics||General Materials Science||Civil and Structural Engineering","Sciences de l'ingénieur","Rayleigh–Bénard convection of a viscoplastic liquid in a trapezoidal enclosure","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,,"International Journal of Mechanical Sciences",,,"105630","Oui",,,"180","true","newSubmission","aut||aut||aut||aut","2023-02-02T12:51:46Z",,"hal-03969650","accept","true",,"1","crossref"
"0d46e865-3247-40c2-ac47-a7ae92ee2a97","10985/13599||10985/191",,"NOURI, Madyen||ARTOZOUL, Julien||CAILLAUD, Aude||AMMAR, Amine||CHINESTA, Francisco||KÖSER, Ole","2023","2023","2022",,,"Several defects might affect a casting part and degrade its quality and the process efficiency. Porosity formation is one of the major defects that can appear in the resulting product. Thus, several research studies aimed at investigating methods that minimize this anomaly. In the present work, a porosity prediction procedure is proposed to assist users at optimizing porosity distribution according to their application. This method is based on a supervised learning approach to predict shrinkage porosity from thermal history. Learning data are generated by a casting simulation software operating for different process parameters. Machine learning was coupled with a modal representation to interpolate thermal history time series for new parameters combinations. By comparing the predicted values of local porosity to the simulated results, it was demonstrated that the proposed model is efficient and can open perspectives in the casting process optimization.",,"10.1007/s12289-022-01677-5",,"1960-6206","http://hdl.handle.net/10985/23271","en","Centre de Angers","Springer Science and Business Media LLC",,"Post-print","Pas de Licence CC","General Materials Science||Physics-based modelling||Smart manufacturing||Model order reduction||Data-driven modelling||Shrinkage porosity","Sciences de l'ingénieur","Shrinkage porosity prediction empowered by physics-based and data-driven hybrid models","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"3","International Journal of Material Forming",,"10985/191",,"Oui",,,"15","true","newSubmission","aut||aut||aut||aut||aut||aut","2023-02-02T10:40:52Z",,"hal-03969397","replace","true",,"1","crossref"
"3e4c687b-b28b-4adb-b985-18cbc083b0ab","10985/13599",,"AMMAR, Amine||ZGHAL, Ali||CHINESTA, Francisco||MOREL, Franck","2015","2016","2015","2015",,"The analysis of materials mechanical behavior involves many computational challenges. In this work, we are addressing the transient simulation of the mechanical behavior when the time of interest is much larger than the characteristic time of the mechanical response. This situation is encountered in many applications, as for example in the simulation of materials aging, or in structural analysis when small-amplitude oscillatory loads are applied during a long period, as it occurs for example when characterizing viscoelastic behaviors by calculating the complex modulus or when addressing fatigue simulations. Moreover, in the case of viscoelastic behaviors, the constitutive equation is many times expressed in an integral form avoiding the necessity of using internal variables, fact that results in an integro-differential model. In order to efficiently simulate such a model, we explore in this work the use of a space-time separated representation.||L'analyse du comportement mécanique des matériaux entraîne de nombreuses difficultés du point de vue numérique. Dans ce travail, nous allons nous focaliser sur l'une d'entre elles, celle associée à la simulation transitoire du comportement mécanique quand l'intervalle temporel d'intérêt est substantiellement plus long que le temps caractéristique associé à la réponse mécanique. Cette situation est fréquemment retrouvée dans la caractérisation rhéologique des matériaux viscoélastiques (pour la détermination du module complexe) ainsi que quand on s'attaque à la simulation de la fatigue. De plus, dans le cas des matriaux viscoélastiques, le comportement est généralement décrit par une loi de comportement intégrale qui évite le besoin d'utiliser des variables internes, donnant lieu à un modèle mécanique integro-différentiel. Pour une résolution efficace, nous analysons ici l'utilisation d'une représentation séparée en espace-temps.",,"10.1016/j.crme.2015.02.002",,"1631-0721","http://hdl.handle.net/10985/9958","en","Centre de Angers","Elsevier Masson",,"Post-print",,"PGD||Viscoelasticity||Integro-differential models||Fatigue||PGD||Viscoélasticité||Modèle integro-differentiel||Fatigue","Sciences de l'ingénieur: Mécanique: Mécanique des matériaux||Sciences de l'ingénieur: Mécanique: Mécanique des solides","On the space-time separated representation of integral linear viscoelastic models||Représentation séparée espace-temps pour des comportements viscoélastiques linaires intégraux","Article dans une revue avec comité de lecture","Internationale",,,,,,"1 Year",,,,"4","Comptes Rendus Mécanique","fr",,"247-263",,,,"343",,,"aut",,,,"unsent","true",,,
"e4196690-d50f-46a9-84b4-84f57e9963b3","10985/13599","yes","NASRI, Mohamed Aziz||ROBERT, Camille||AMMAR, Amine||MOREL, Franck||EL AREM, Saber","2016","2016","2015","2016",,"Les modélisations numériques des matériaux à l’échelle de la microstructure se sont fortement développées au cours des deux dernières décennies. Malheureusement, les méthodes de résolution classiques ne permettent pas de simuler les agrégats polycristallins au-delà de quelques dizaines de cycles à cause du temps de calcul prohibitif. Ce travail présente le développement d’une méthode numérique pour la résolution par la méthode des éléments finis d’agrégats polycristallins soumis à un chargement cyclique. La première idée est de maintenir la matrice de rigidité constante. La deuxième proposition est d’utiliser une méthode de réduction dimensionnelle en espace/temps. Les résultats montrent un gain de temps relativement important tout en gardant une très bonne précision",,,,,"http://hdl.handle.net/10985/10755","fr","Centre de Angers||Centre de Bordeaux-Talence","AFM",,"Post-print",,"PGD||Eléments finis||Plasticité||Agrégats polycristallins","Sciences de l'ingénieur: Mécanique","Réduction dimensionnelle de type PGD pour le calcul numérique d’agrégats polycristallin soumis à des chargements cycliques","Communication avec acte","Nationale","Lyon","2015-08-25","Congrès Français de Mécanique (22; 2015; Lyon)","France",,,,,"Non",,,,,"7","Oui","Oui","CFM 2015",,,,"aut",,,"hal-01310820","accept",,,"1",
"4b0f9fd7-c73f-4d9d-8b6a-ed2b454ef316","10985/13599",,"NASRI, Mohamed Aziz||AGUADO, Jose Vicente||AMMAR, Amine||CUETO, Elias||CHINESTA, Francisco||ROBERT, Camille||MOREL, Franck||EL AREM, Saber","2015","2016","2015","2015",,"Forming processes usually involve irreversible plastic transformations. The calculation in that case becomes cumbersome when large parts and processes are considered. Recently Model Order Reduction techniques opened new perspectives for an accurate and fast simulation of mechanical systems, however nonlinear history-dependent behaviors remain still today challenging scenarios for the application of these techniques. In this work we are proposing a quite simple non intrusive strategy able to address such behaviors by coupling a separated representation with a POD-based reduced basis within an incremental elastoplastic formulation.",,,,"1013-9826","http://hdl.handle.net/10985/9514","en","Centre de Angers","Key Engineering Materials",,"Post-print",,"Model Order Reduction||Proper Generalized Decomposition||Elastoplasticity","Sciences de l'ingénieur: Mécanique","Separated representation of incremental elastoplastic simulations","Communication avec acte","Internationale","Graz","2015-04","ESAFORM 2015","Autriche",,"1 Year",,,,,,,,"1285-1293",,,"ESAFORM 2015","651-653",,,"aut",,,,"unsent","true",,,
"f456a476-ad38-4659-8119-cde31a6c304e","10985/13599","yes","NASRI, Mohamed Aziz||ROBERT, Camille||AMMAR, Amine||MOREL, Franck||EL AREM, Saber","2016","2016","2015","2016",,"none",,,,,"http://hdl.handle.net/10985/10760","en","Centre de Aix en Provence||Centre de Angers",,,"Pre-print",,,"Sciences de l'ingénieur: Mécanique","Proper Generalized Decomposition (PGD) for numerical calculation of polycrystalline aggregates under cyclic loading","Communication sans acte","Non spécifiée","Cachan","2015-11-05","Workshop on  Reduced Basis, POD and PGD Model Reduction Techniques","France",,,,,"Non",,,,,,"Oui","Oui",,,,,"aut",,,"hal-01311840","accept",,,"1",
"9fa3add6-5103-443c-9cf6-611988d8d5a5","10985/13599",,"NASRI, Mohamed Aziz||AMMAR, Amine||ROBERT, Camille||MOREL, Franck||EL AREM, Saber","2019","2019","2018",,,"The numerical modelling of the behaviour of materials at the microstructural scale has been greatly developed over the last two decades. Unfortunately, conventional resolution methods cannot simulate polycrystalline aggregates beyond tens of loading cycles, and they do not remain quantitative due to the plasticity behaviour. This work presents the development of a numerical solver for the resolution of the Finite Element modelling of polycrystalline aggregates subjected to cyclic mechanical loading. The method is based on two concepts. The first one consists in maintaining a constant stiffness matrix. The second uses a time/space model reduction method. In order to analyse the applicability and the performance of the use of a space–time separated representation, the simulations are carried out on a three-dimensional polycrystalline aggregate under cyclic loading. Different numbers of elements per grain and two time increments per cycle are investigated. The results show a significant CPU time saving while maintaining good precision. Moreover, increasing the number of elements and the number of time increments per cycle, the model reduction method is faster than the standard solver.",,"10.1016/j.crme.2017.11.009",,"1631-0721","http://hdl.handle.net/10985/16697","en","Centre de Angers","Elsevier Masson",,"Post-print",,,"Sciences de l'ingénieur: Mécanique||Sciences de l'ingénieur: Mécanique","Proper Generalized Decomposition (PGD) for the numerical simulation of polycrystalline aggregates under cyclic loading","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Comptes Rendus Mécanique",,,"20","Oui",,,,"true","newSubmission","aut","2019-09-12T13:07:06Z",,"hal-02285120","accept","true",,"1","crossref"
"44345841-bd0d-4dfd-8105-270bbf557b13","10985/13599",,"NASRI, Mohamed Aziz||AMMAR, Amine||CHINESTA, Francisco||ROBERT, Camille||MOREL, Franck||EL AREM, Saber","2016","2017","2016","2016",,"Forming processes usually involve irreversible plastic transformations. The calculation in that case becomes cumbersome when  large  parts  and  processes  are  considered.  Recently  Model  Order  Reduction  techniques  opened  new  perspectives  for  an accurate and fast simulation of mechanical systems. In some processes, plastic deformations remain very localized, for example in the immediate neighborhood of the surface. In that case, the in-plane characteristic dimension is several orders of magnitude higher than the one related to the deepness in which plasticity localizes. In those situations the use of standard mesh-based 3D discretization is challenging because the extremely different characteristic dimensions that to capture all the information requires the use of millions of nodes.",,,,"2198-9907","http://hdl.handle.net/10985/10754","en","Centre de Angers","Springer",,"Post-print",,,"Sciences de l'ingénieur: Mécanique","On the Model Order Reduction of Confined Plasticity","Communication avec acte","Internationale","Nantes","2016-04-27","ESAFORM (19 ; 2016 ; Nantes)","France",,"2017-12-31",,,"Non",,,,,"6","Oui","Oui","19th ESAFORM Conference",,,,"aut",,,"hal-01310812","accept",,,"1",
"3ccd456b-085c-4c2b-878b-f55006ffe925","10985/13599",,"AMMAR, Amine||CHINESTA, Francisco||KEUNINGS, Roland||ABISSET-CHAVANNE, Emmanuelle","2016","2016","2016","2016",,"Permeability is the fundamental macroscopic material property needed to quantify the flow in a fibrous medium viewed as a porous medium. Composite processing models require the permeability as input data to predict flow patterns and pressure fields. In a previous work, the expressions of macroscopic permeability were derived in a double-scale porosity medium for both Newtonian and generalized Newtonian (shear-thinning) resins. In the linear case, only a microscopic calculation on a representative volume is required, implying as many microscopic calculations as there are representative microscopic volumes in the whole fibrous structure. In the non-linear case, and even when the porous microstructure can be described by a unique representative volume, a large number of microscopic calculations must be carried out as the microscale resin viscosity depends on the macroscopic velocity, which in turn depends on the permeability that results from a microscopic calculation. An original and efficient offline-online procedure was proposed for the solution of non-linear flow problems related to generalized Newtonian fluids in porous media. In this paper, this procedure is generalized to quasi-Newtonian fluids in order to evaluate the effect of extensional viscosity on the resulting upscaled permeability. This work constitutes a natural step forward in the definition of equivalent saturated permeabilities for linear and non-linear fluids.",,"10.1007/s12289-016-1300-0","1960-6214","1960-6206","http://hdl.handle.net/10985/11390","en","Centre de Angers","Springer Verlag",,"Post-print",,"Permeability||Computational homogenization||Quasi-Newtonian fluids||Generalized Newtonian fluids||Extensional viscosity||Composite materials||Model order reduction||Proper generalized decomposition||Parametric solutions","Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Flow modelling of quasi-Newtonian fluids in two-scale fibrous fabrics: Advanced simulations","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"International Journal of Material Forming",,,"1-10","Oui",,,,,,"aut",,,"hal-01410118","accept",,,"1",
"3619b176-b955-4916-bdb8-184935af16da","10985/191||10985/13599",,"PEREZ, Marta||SCHEUER, Adrien||AMMAR, Amine||CHINESTA, Francisco||KEUNINGS, Roland||ABISSET-CHAVANNE, Emmanuelle","2020","2020","2019",,,"When addressing the flow of concentrated suspensions composed of rods, dense clusters are observed. Thus, the adequate modelling and simulation of such a flow requires addressing the kinematics of these dense clusters and their impact on the flow in which they are immersed. In a former work, we addressed a first modelling framework of these clusters, assumed so dense that they were considered rigid and their kinematics (flow-induced rotation) were totally defined by a symmetric tensor c with unit trace representing the cluster conformation. Then, the rigid nature of the clusters was relaxed, assuming them deformable, and a model giving the evolution of both the cluster shape and its microstructural orientation descriptor (the so-called shape and orientation tensors) was proposed. This paper compares the predictions coming from those models with finer-scale discrete simulations inspired from molecular dynamics modelling.",,"10.1007/s00161-018-0659-1","1432-0959","0935-1175","http://hdl.handle.net/10985/17967","en","Centre de Paris","Springer Verlag",,"Post-print",,"Aggregate - Cluster - Concentrated suspensions - Jeffery’s equation - Multi-scale modelling - Non-ellipsoidal particles","Sciences de l'ingénieur: Matériaux","On the multi-scale description of micro-structured fluids composed of aggregating rods","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"4","Continuum Mechanics and Thermodynamics",,,"955-967","Oui",,,"31","true","newSubmission","aut","2020-01-28T15:48:09Z","<?xml version=""1.0"" encoding=""utf-8""?> <sword:error xmlns:sword=""http://purl.org/net/sword/error/"" xmlns=""http://www.w3.org/2005/Atom"" href=""http://purl.org/net/sword/error/ErrorBadRequest"">   <title>ERROR</title>   <updated>2020-05-12T09:47:26+02:00</updated>   <author>     <name>HAL SWORD API Server</name>   </author>   <source>     <generator uri=""https://api.archives-ouvertes.fr/sword"" version=""1.0"">hal@ccsd.cnrs.fr</generator>   </source>   <summary>Some parameters sent with the request were not understood</summary>   <sword:treatment>processing failed</sword:treatment>   <sword:verboseDescription>Paper has moved to hal-02163613, verify your sync is allready valid.  if yes, change the hal identifier on your side</sword:verboseDescription>   <link rel=""alternate"" href=""https://api.archives-ouvertes.fr"" type=""text/html""/> </sword:error>","hal-02458429","accept","true","metadataUpdate","1",
"5eceef3a-13c4-4000-baa1-23258a0f8aed","10985/13599",,"ZGHAL, Jihed||AMMAR, Amine||CHINESTA, Francisco||BINETRUY, Christophe||ABISSET-CHAVANNE, Emmanuelle","2019","2019","2017",,,"Several studies showed that thin-plies composite laminates apparently exhibit higher strength than its counterpart using thicker plies. In this work, a high-resolution numerical discretization based on the use of in-plane-out-of-plane separated  representations within the Proper Generalized Decomposition   PGD   framework is performed in di erent composites laminates for determining the e ect of ply-thickness on the laminate sti ness. The results reveal that the global sti ness increases with the ply-thickness reduction. The analysis also reveals that this mechanical enhancement is due to structural e ects and not to the mechanical con nement initially advanced.",,"10.1016/j.compstruct.2017.03.083",,"0263-8223","http://hdl.handle.net/10985/16635","en","Centre de Angers","Elsevier",,"Post-print",,,"Sciences de l'ingénieur: Mécanique","High-resolution elastic analysis of thin-ply composite laminates","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Composite Structures",,,"12","Oui",,,,"true","newSubmission","aut","2019-09-12T08:33:59Z",,"hal-02284774","accept","true",,"1","crossref"
"90d28099-ae6d-4404-808d-111ed85cae21","10985/13599",,"PEREZ, Marta||BARASINSKI, Anais||CHINESTA, Francisco||AMMAR, Amine||KEUNINGS, Roland||ABISSET-CHAVANNE, Emmanuelle","2015","2015","2015","2015",,"Nanocomposites allow for a significant enhancement of functional properties, in particular electrical conduction. In order to optimize materials and parts, predictive models are required to evaluate particle distribution and orientation. Both are key parameters in order to evaluate percolation and the resulting electrical networks. Many forming processes involve flowing suspensions for which the final particle orientation could be controlled by means of the flow and the electric field. In view of the multiscale character of the problem, detailed descriptions are defined at the microscopic scale and then coarsened to be applied efficiently in process simulation at the macroscopic scale. The first part of this work revisits the different modeling approaches throughout the different description scales. Then, modeling of particle contacts is addressed as they determine the final functional properties, in particular electrical conduction. Different descriptors of rod contacts are proposed and analyzed. Numerical results are discussed, in particular to evaluate the impact of closure approximations needed to derive a macroscopic description.",,"10.1186/s40323-015-0044-6",,"2213-7467","http://hdl.handle.net/10985/10253","en","Centre de Angers","SpringerOpen",,"Post-print",,"Nanocomposites||Electrical properties||Multi-scale modeling||Fokker-Planck equation||Interaction tensor","Informatique: Ingénierie assistée par ordinateur||Sciences de l'ingénieur: Mécanique: Mécanique des matériaux","On the multi‑scale description of electrical conducting suspensions involving perfectly dispersed rods","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"23","Advanced Modeling and Simulation in Engineering Sciences",,,"1-24",,,,"2",,,"aut","2020-01-20T12:05:00Z",,"hal-02445674","accept","true",,"1",
"67a39c2c-06dc-4cb3-a0f2-90823f76a9fc","10985/13599",,"CHINESTA, Francisco||AMMAR, Amine||CUETO, Elias||ABISSET-CHAVANNE, Emmanuelle","2015","2015","2015","2015",,"The fine description of complex fluids can be carried out by describing the evolution of each individual constituent (e.g. each particle, each macromolecule, etc.). This procedure, despite its conceptual simplicity, involves many numerical issues, the most challenging one being that related to the computing time required to update the system configuration by describing all the interactions between the different individuals. Coarse grained approaches allow alleviating the just referred issue: the system is described by a distribution function providing the fraction of entities that at certain time and position have a particular conformation. Thus, mesoscale models involve many different coordinates, standard space and time, and different conformational coordinates whose number and nature depend on the particular system considered. Balance equation describing the evolution of such distribution function consists of an advection-diffusion partial differential equation defined in a high dimensional space. Standard mesh-based discretization techniques fail at solving high-dimensional models because of the curse of dimensionality. Recently the authors proposed an alternative route based on the use of separated representations. However, until now these approaches were unable to address the case of advection dominated models due to stabilization issues. In this paper this issue is revisited and efficient procedures for stabilizing the advection operators involved in the Boltzmann and Fokker-Planck equation within the PGD framework are proposed.","Authors acknowledge the support of Spanish and Frenchministries through grants CICYTDPI2011-27778-C02-01/02 and ANR COSINUS 2010 SIMDREAM. F. Chinesta also acknowledge the Institut Universitaire de France – IUF.","10.4208/cicp.2014.m326",,"1815-2406","http://hdl.handle.net/10985/10237","en","Centre de Angers","Global Science Press",,"Post-print",,"Boltzmann equation||Fokker-Planck equation||proper gene||multidimensional models||convective stabilization","Informatique: Ingénierie assistée par ordinateur","Efficient Stabilization of Advection Terms Involved in Separated Representations of Boltzmann and Fokker-Planck Equations","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"4","Communications in Computational Physics",,,"975-1006",,,,"17",,,"aut",,,"hal-01206757","accept",,,"1",
"db56c1b2-0b0c-4300-b7d0-e60921af44a5","10985/13599",,"IBAÑEZ, Ruben||AMMAR, Amine||GONZALEZ, David||CUETO, Elias||HUERTA, Antonio||DUVAL, Jean-Louis||CHINESTA, Francisco||ABISSET-CHAVANNE, Emmanuelle","2019","2019","2018",,,"Sparse model identification by means of data is especially cumbersome if the sought dynamics live in a high dimensional space. This usually involves the need for large amount of data, unfeasible in such a high dimensional settings. This well-known phenomenon, coined as the curse of dimensionality, is here overcome by means of the use of separate representations. We present a technique based on the same principles of the Proper Generalized Decomposition that enables the identification of complex laws in the low-data limit. We provide examples on the performance of the technique in up to ten dimensions.",,"10.1155/2018/5608286","1099-0526","1076-2787","http://hdl.handle.net/10985/16676","en","Centre de Angers","Wiley",,"Post-print",,,"Sciences de l'ingénieur: Matériaux","A Multidimensional Data-Driven Sparse Identification Technique: The Sparse Proper Generalized Decomposition","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,,"Complexity",,,"1-11","Oui",,,"2018","true","newSubmission","aut","2020-09-15T12:09:06Z",,"hal-02285019","accept","true",,"1","crossref"
"370b3ec4-b593-4a4e-aad0-0c77909b7f9e","10985/13599",,"MEZHER, Rabih||LE CORRE, Steven||AMMAR, Amine||CHINESTA, Francisco||ABISSET-CHAVANNE, Emmanuelle","2015","2015","2013","2015",,"When suspensions involving rigid rods become too concentrated, standard dilute theories fail to describe their behavior. Rich microstructures involving complex clusters are observed, and no model allows describing its kinematics and rheological effects. In previous works the authors propose a first attempt to describe such clusters from a micromechanical model, but neither its validity nor the rheological effects were addressed. Later, authors applied this model for fitting the rheological measurements in concentrated suspensions of carbon nanotubes (CNTs) by assuming a rheo-thinning behavior at the constitutive law level. However, three major issues were never addressed until now: (i) the validation of the micromechanical model by direct numerical simulation; (ii) the establishment of a general enough multi-scale kinetic theory description, taking into account interaction, diffusion and elastic effects; and (iii) proposing a numerical technique able to solve the kinetic theory description. This paper focuses on these three major issues, proving the validity of the micromechanical model, establishing a multi-scale kinetic theory description and, then, solving it by using an advanced and efficient separated representation of the cluster distribution function. These three aspects, never until now addressed in the past, constitute the main originality and the major contribution of the present paper.",,"10.3390/e15072805",,"1099-4300","http://hdl.handle.net/10985/10264","en","Centre de Angers","MDPI",,"Post-print",,"kinetic theory||concentrated suspensions||aggregates||Fokker-Planck equation||proper generalized decomposition||micromechanics","Informatique: Ingénierie assistée par ordinateur||Sciences de l'ingénieur: Mécanique: Mécanique des fluides","Kinetic Theory Microstructure Modeling in Concentrated Suspensions","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"7","Entropy",,,"2805-2832",,,,"15",,,"aut",,,"hal-01207104","accept",,,"1",
"d27db79d-b52d-4ff8-81ab-fd5a0e8d9e45","10985/13599",,"ROBERT, Camille||AMMAR, Amine||GERMAIN, Guénaël||AYED, Yessine","2019","2019","2017",,,"The development of computation means has allowed the simulation of complex mechanical problems. The first simulations of manufacturing processes at the microstructure scale, namely in the field of machining, have recently emerged. In this study, and on the basis of previous research, a novel approach to machining simulation is proposed. A crystal plasticity behavior law has thus been implemented and its parameters have been identified, for each of the two phases constituting the material. This is achieved through experimental tests conducted under extreme conditions of temperature and strain rates. Numerical models are composed of grains in the form of Voronoï cells. Random crystal orientations have also been assigned to each grain. This has subsequently allowed the simulation of the machining process. Access to local physical parameters such as crystal orientations, their evolution and phase transition thus presents a major breakthrough in this field.",,,,"0168-874X","http://hdl.handle.net/10985/16581","en","Centre de Angers",,,"Post-print||Post-print",,,"Sciences de l'ingénieur||Sciences de l'ingénieur","Orthogonal micro-cutting modeling of the Ti17 titanium alloy using the crystal plasticity theory","Article dans une revue avec comité de lecture||Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref||crossref",,,"Finite Elements in Analysis and Design",,,"189-202","Oui",,,"134","true","newSubmission","aut","2019-09-10T13:28:36Z",,"hal-02283179","accept","true",,"1","crossref"
"838770b8-b84d-4eaf-ab3e-8901596866ad","10985/13599",,"AMMAR, Amine||FURET, Benoit||GERMAIN, Guénaël||AYED, Yessine","2014","2014","2013","2014",,"This article presents the results of an experimental study on the Ti17 titanium alloy, which was carried out to analyze tool wear and the degradation mechanisms of an uncoated tungsten carbide tool insert. Two machining conditions, roughing and finishing, have been studied under different lubrication conditions. The experimental procedure included measurement of the cutting forces and the surface roughness. Different techniques have been used to explain the tool wear mechanisms. Distribution maps of the elemental composition of the titanium alloy and the tool inserts have been created using Energy Dispersive X-ray Spectroscopy (EDS). An area of material deposition on the tool rake face, characterized by a high titanium concentration has been observed. The width of this area and the concentration of titanium, decrease when increasing water jet pressure. The study shows that wear mechanisms, with and without high-pressure water jet assistance (HPWJA) are not the same. For example, for the roughing condition using conventional lubrication, the temperature in the cutting area becomes very high, this causes plastic deformation of the cutting edge which results in its rapid collapse. By contrast, this problem disappears when machining with HPWJA. In addition, the evolution of flank wear (VB) is stabilized with high-pressure lubrication. In this case, the most critical degradation mode is due to notch wear (VBn) leading to the sudden rupture of the cutting edge.","Région Pays de la Loire","10.1016/j.wear.2013.06.018",,"0043-1648","http://hdl.handle.net/10985/8608","en","Centre de Angers","Elsevier",,"Post-print",,"Water jet assisted machining||Tool wear mechanisms||EDS analysis||Surface roughness||Tool life||Titanium alloy","Sciences de l'ingénieur: Génie des procédés||Sciences de l'ingénieur: Mécanique","Degradation modes and tool wear mechanisms in finish and rough machining of Ti17 Titanium alloy under high-pressure water jet assistance","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"1-2","Wear",,,"228-237",,,,"305",,,"aut",,,"hal-01068090","accept",,,"1",
"ec64d204-b440-4145-ab1c-9de64c62e559","10985/13599",,"AMMAR, Amine||FURET, Benoit||GERMAIN, Guénaël||AYED, Yessine","2016","2017","2016","2016",,"Understanding the physics of chip formation in machining operations is often difficult due to the complexity of the phenomena involved, such as the extreme and complex loading conditions that occur in the cutting zone. In order to model the machining process, it is necessary to use a constitutive behavior law that is capable of reproducing as accurately as possible the behavior of the material under these extreme conditions. In this context, this paper presents a study of the mechanical behavior of the Ti17 titanium alloy at high strain rates and high temperatures. This has been achieved by undertaking compression and shear tests over a wide range of strain rates (from 10−1 s−1 to 100 s−1) and temperatures (from 25 to 800 ◦C). The results show that the Ti17 alloy is sensitive to strain rate, especially for strain rates greater than 1 s−1. In addition, the alloy retains good mechanical properties at high temperature (up to 500 ◦C). Based on the experimental results, the parameter of the Johnson-Cook constitutive equation have been identified using the inverse method. Some weaknesses in the model have been highlighted after the identification phase, especially in terms of the m and C parameters. A modification of the model has been proposed.","Acknowledgments Authors would like to thank the French Région des Pays de la Loire and the company Timet (Ugine-France) for funding the project.","10.1007/s00170-016-9476-5","1433-3015","0268-3768","http://hdl.handle.net/10985/11314","en","Centre de Angers","Springer Verlag",,"Post-print",,"High strain rate||High temperature||Johnson-Cook||Characterization||Titanium alloy||Machining","Sciences de l'ingénieur: Mécanique: Mécanique des matériaux","Thermo-mechanical characterization of the Ti17 titanium alloy under extreme loading conditions","Article dans une revue avec comité de lecture","Internationale",,,,,,"2017-09-01",,,,,"International Journal of Advanced Manufacturing Technology",,,"1-11","Oui",,,,,,"aut",,,"hal-01391021","accept",,,"1",
"e515b39c-7e75-4ae2-bb32-968b40d66a97","10985/13599",,"ROBERT, Camille||AMMAR, Amine||GERMAIN, Guénaël||AYED, Yessine","2015","2017","2016","2015",,"The aim of this study is to develop a new numerical cutting model that includes fluid structure interaction and to take into account heat transfer between the water-jet, the workpiece and the chip. This has been achieved using a CEL (Coupled–Eulerian–Lagrangian) technique, an algorithm has been developed to ensure heat exchange between the fluid and the structure. This new model allows decoupling of the mechanical and the thermal effects of the water-jet on chip formation and fragmentation. It has been demonstrated that fragmentation of the chip is ensured by the combination of the thermal and the mechanical effects of the water-jet. Moreover, the tool rake temperature is reduced by more than 400 °C, the tool/chip contact length is also decreased by about 30%.","The authors would like to thank the French region “Pays de la Loire” for their financial support of this project.","10.1016/j.finel.2015.09.003",,"0168-874X","http://hdl.handle.net/10985/10378","en","Centre de Angers","Elsevier",,"Post-print",,"Assisted machining||Chip formation||Fluid/structure interaction||High-pressure water-jet||Titanium alloys","Sciences de l'ingénieur: Génie des procédés","Development of a numerical model for the understanding of the chip formation in high-pressure water-jet assisted machining","Article dans une revue avec comité de lecture","Internationale",,,,,,"2 Years",,,,,"Finite Elements in Analysis and Design",,,"1-8",,,,"108",,,"aut",,,"hal-01224932","accept",,,"1",
"09052ec5-0e27-4bf4-9a3b-925b5705090e","10985/13599",,"AMMAR, Amine||FURET, Benoit||GERMAIN, Guénaël||AYED, Yessine","2015","2015","2013","2015",,"Titanium alloys are known for their excellent mechanical properties, especially at high temperature. But this specificity of titanium alloys can cause high cutting forces as well as a significant release of heat that may entail a rapid wear of the cutting tool. To cope with these problems, research has been taken in several directions. One of these is the development of assistances for machining. In this study, we investigate the high pressure coolant assisted machining of titanium alloy Ti17. High pressure coolant consists of projecting a jet of water between the rake face of the tool and the chip. The efficiency of the process depends on the choice of the operating parameters of machining and the parameters of the water jet such as its pressure and its diameter. The use of this type of assistance improves chip breaking and increases tool life. Indeed, the machining of titanium alloys is generally accompanied by rapid wear of cutting tools, especially in rough machining. The work done focuses on the wear of uncoated tungsten carbide tools during machining of Ti17. Rough and finish machining in conventional and in high pressure coolant assistance conditions were tested. Different techniques were used in order to explain the mechanisms of wear. These tests are accompanied by measurement of cutting forces, surface roughness and tool wear. The Energy-dispersive X-ray spectroscopy (EDS) analysis technique made it possible to draw the distribution maps of alloying elements on the tool rake face. An area of material deposition on the rake face, characterized by a high concentration of titanium, was noticed. The width of this area and the concentration of titanium decreases in proportion with the increasing pressure of the coolant. The study showed that the wear mechanisms with and without high pressure coolant assistance are different. In fact, in the condition of conventional machining, temperature in the cutting zone becomes very high and, with lack of lubrication, the cutting edge deforms plastically and eventually collapses quickly. By contrast, in high pressure coolant assisted machining, this problem disappears and flank wear (VB) is stabilized at high pressure. The sudden rupture of the cutting edge observed under these conditions is due to the propagation of a notch and to the crater wear that appears at high pressure. Moreover, in rough condition, high pressure assistance made it possible to increase tool life by up to 400%.","Authors would like to thank « Région des pays de la loire » for funding of the project which is part of a PhD thesis","10.4028/www.scientific.net/KEM.554-557.1961","1662-9795","1013-9826","http://hdl.handle.net/10985/9959","en","Centre de Angers","Trans Tech Publications",,"Post-print",,"EDS||Titanium alloy||Tool Life||Water Jet Assisted Machining||Wear","Sciences de l'ingénieur: Mécanique: Mécanique des matériaux","Experimental Study of tool Wear Mechanisms in Conventional and High Pressure Coolant Assisted Machining of Titanium Alloy Ti17","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Key Engineering Materials",,,"1961-1966",,,,"554-557",,,"aut",,,"hal-01195928","accept",,,"1",
"413164ae-c886-4034-9d1e-27d792a5c1f3","10985/13599",,"AMMAR, Amine||FURET, Benoit||GERMAIN, Guénaël||AYED, Yessine","2015","2017","2015","2015",,"This paper presents experimental results concerning the machinability of the titanium alloy Ti17 with and without high-pressure water jet assistance (HPWJA) using uncoated WC/Co tools. For this purpose, the influence of the cutting speed and the water jet pressure on the evolution of tool wear and cutting forces have been investigated. The cutting speed has been varied between 50 m/min and 100 m/min and the water jet pressure has been varied from 50 bar to 250 bar. The optimum water jet pressure has been determined, leading to an increase in tool life of approximately 9 times. Compared to conventional lubrication, an increase of about 30% in productivity can be obtained.","The authors would like to thank the French region “Pays de la loire” for funding the project.","10.1016/j.precisioneng.2015.06.004",,"0141-6359","http://hdl.handle.net/10985/9940","en","Centre de Angers","Elsevier",,"Post-print",,"Tool wear||Tool life||High pressure||Cutting forces||Titanium alloy","Sciences de l'ingénieur: Mécanique: Génie mécanique","Tool wear analysis and improvement of cutting conditions using the high-pressure water-jet assistance when machining the Ti17 titanium alloy","Article dans une revue avec comité de lecture","Internationale",,,,,,"2 Years",,,,,"Precision Engineering",,,"294-301",,,,"42",,,"aut","2020-02-20T15:40:09Z",,"hal-02486151","accept","true",,"1",
"56bcbc9e-ea44-4619-a1b5-acb7f377d319","10985/191||10985/13599",,"KAZEMZADEH-PARSI, Mohammad-Javad||AMMAR, Amine||CHINESTA SORIA, Francisco","2024","2024","2023",,,"In the present work, the general and well-known model reduction technique, PGD (Proper Generalized Decomposition), is used for parametric analysis of thermo-elasticity of FGMs (Functionally Graded Materials). The FGMs have important applications in space technologies, especially when a part undergoes an extreme thermal environment. In the present work, material gradation is considered in one, two and three directions, and 3D heat transfer and theory of elasticity equations are solved to have an accurate temperature field and be able to consider all shear deformations. A parametric analysis of FGM materials is especially useful in material design and optimization. In the PGD technique, the field variables are separated to a set of univariate functions, and the high-dimensional governing equations reduce to a set of one-dimensional problems. Due to the curse of dimensionality, solving a high-dimensional parametric problem is considerably more computationally intensive than solving a set of one-dimensional problems. Therefore, the PGD makes it possible to handle high-dimensional problems efficiently. In the present work, some sample examples in 4D and 5D computational spaces are solved, and the results are presented.",,"10.3390/ma16041753",,,"http://hdl.handle.net/10985/24728",,"Centre de Paris",,,,,"proper generalized decomposition||thermo-elasticity||a priori model order reduction||functionally graded material||thick plates","Sciences de l'ingénieur","Parametric Analysis of Thick FGM Plates Based on 3D Thermo-Elasticity Theory: A Proper Generalized Decomposition Approach","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,,"Materials",,,,,,,,,,"aut||aut||aut",,,,"unsent",,,,
"5c426415-e433-4057-8b6e-44f5f5b47c47","10985/191||10985/13599",,"IBAÑEZ, Ruben||CASTERAN, Fanny||ARGERICH, Clara||HASCOET, Nicolas||AMMAR, Amine||CASSAGNAU, Philippe||CHINESTA, Francisco||GHNATIOS, Chady","2020","2020","2020",,,"This paper analyzes the ability of different machine learning techniques, able to operate in the low-data limit, for constructing the model linking material and process parameters with the properties and performances of parts obtained by reactive polymer extrusion. The use of data-driven approaches is justified by the absence of reliable modeling and simulation approaches able to predict induced properties in those complex processes. The experimental part of this work is based on the in situ synthesis of a thermoset (TS) phase during the mixing step with a thermoplastic polypropylene (PP) phase in a twin-screw extruder. Three reactive epoxy/amine systems have been considered and anhydride maleic grafted polypropylene (PP-g-MA) has been used as compatibilizer. The final objective is to define the appropriate processing conditions in terms of improving the mechanical properties of these new PP materials by reactive extrusion.",,"10.3390/fluids5020094",,"2311-5521","http://hdl.handle.net/10985/19137","en","Centre de Paris","MDPI",,"Post-print",,"reactive extrusion||data-driven||machine learning||polymer processing","Sciences de l'ingénieur: Matériaux","On the data-driven modeling of reactive extrusion","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref||crossref",,"2","Fluids",,"10985/13599","1-23","Oui",,,"5","true","newSubmission","aut","2020-07-20T09:16:24Z",,"hal-02902692","accept","true",,"1","crossref"
"0b2b0bd2-114f-4ce6-93aa-f626d3efe2cf","10985/191||10985/13597||10985/13599",,"AMMAR, Amine||GHNATIOS, Chady||DELPLACE, Frank||BARASINSKI, Anais||DUVAL, Jean-Louis||CUETO, Elias||CHINESTA, Francisco","2020",,"2020",,,"Composite manufacturing processes usually proceed from preimpregnated preforms that are consolidated by simultaneously applying heat and pressure, so as to ensure a perfect contact compulsory for making molecular diffusion possible. However, in practice, the contact is rarely perfect. This results in a rough interface where air could remain entrapped, thus affecting the effective thermal conductivity. Moreover, the interfacial melted polymer is squeezed flowing in the rough gap created by the fibers located on the prepreg surfaces. Because of the typical dimensions of a composite prepreg, with thickness orders of magnitude smaller than its other in-plane dimensions, and its surface roughness having a characteristic size orders of magnitude smaller than the prepreg thickness, high-fidelity numerical simulations for elucidating the impact of surface and interface roughness remain today, despite the impressive advances in computational availabilities, unattainable. This work aims at elucidating roughness impact on heat conduction and the effective viscosity of the interfacial polymer squeeze flow by using an advanced numerical strategy able to reach resolutions never attained until now, a sort of numerical microscope able to attain the scale of the smallest geometrical detail.",,"10.1002/nme.6448","1097-0207","0029-5981","http://hdl.handle.net/10985/19486","en","Centre de Paris","Wiley",,"Post-print",,"General Engineering||Applied Mathematics||Numerical Analysis","Sciences de l'ingénieur: Matériaux","On the effective conductivity and the apparent viscosity of a thin rough polymer interface using PGD‐based separated representations","Article dans une revue avec comité de lecture","Internationale",,,,,"2021-06-15","2021-06-15",,"crossref",,"23","International Journal for Numerical Methods in Engineering",,"10985/13597||10985/13599","5256-5274","Oui",,,"121","true","newSubmission","aut||aut||aut||aut||aut||aut||aut",,"<?xml version=""1.0"" encoding=""utf-8""?> <sword:error xmlns:sword=""http://purl.org/net/sword/error/"" xmlns=""http://www.w3.org/2005/Atom"" href=""http://purl.org/net/sword/error/ErrorBadRequest"">   <title>ERROR</title>   <updated>2020-11-30T17:23:22+01:00</updated>   <author>     <name>HAL SWORD API Server</name>   </author>   <source>     <generator uri=""https://api.archives-ouvertes.fr/sword"" version=""1.0"">hal@ccsd.cnrs.fr</generator>   </source>   <summary>Some parameters sent with the request were not understood</summary>   <sword:treatment>processing failed</sword:treatment>   <sword:verboseDescription>{""duplicate-entry"":{""hal-02902716"":{""doi"":""1.0""}}}</sword:verboseDescription>   <link rel=""alternate"" href=""https://api.archives-ouvertes.fr"" type=""text/html""/> </sword:error>",,"unsent","true","newSubmission||newSubmission",,"crossref"
"ed3815b6-1e81-4fe9-80f2-0e91c0149d15","10985/191||10985/13599",,"REILLE, Agathe||HASCOET, Nicolas||AMMAR, Amine||CUETO, Elias||DUVAL, Jean-Louis||CHINESTA, Francisco||KEUNINGS, Roland||GHNATIOS, Chady","2020","2020","2019",,,"The present work aims at proposing a new methodology for learning reduced models from a small amount of data. It is based on the fact that discrete models, or their transfer function counterparts, have a low rank and then they can be expressed very efficiently using few terms of a tensor decomposition. An efficient procedure is proposed as well as a way for extending it to nonlinear settings while keeping limited the impact of data noise. The proposed methodology is then validated by considering a nonlinear elastic problem and constructing the model relating tractions and displacements at the observation points.",,"10.1016/j.crme.2019.11.003",,"1631-0721","http://hdl.handle.net/10985/18539","en","Centre de Paris","Elsevier Masson",,"Post-print",,"Advanced regression - Machine learning - Mode decomposition - Nonlinear reduced modeling - PGD - Tensor formats","Sciences de l'ingénieur: Matériaux","Incremental dynamic mode decomposition: A reduced-model learner operating at the low-data limit","Article dans une revue avec comité de lecture","Internationale",,,,,,,,,,"11","Comptes Rendus Mécanique",,"10985/13599","780-792","Oui",,,"347","true","newSubmission","aut","2020-05-04T08:51:41Z",,"hal-02561899","accept","true",,"1",
"87300e33-d39d-49e8-913d-61e27cdf26e7","10985/191||10985/13598||10985/13599",,"AMMAR, Amine||CUETO, Elias||DUVAL, Jean-Louis||CHINESTA, Francisco||ABISSET-CHAVANNE, Emmanuelle||GHNATIOS, Chady","2019",,"2019",,,"This work aims at proposing a new procedure for parametric problems whose separated representation has been considered difficult, or whose SVD compression impacted the results in terms of performance and accuracy. The proposed technique achieves a fully separated representation for layered domains with interfaces exhibiting waviness or – more generally – deviating from planar surfaces, parallel to the coordinate plane. This will make possible a simple separated representation, equivalent to others, already analyzed in some of our former works. To prove the potentialities of the proposed approach, two benchmarks will be addressed, one of them involving an efficient space–time separated representation achieved by considering the same rationale.",,"10.1016/j.cma.2019.05.047",,"0045-7825","http://hdl.handle.net/10985/15677","en","Centre de Paris","Elsevier",,"Post-print",,"PGD; Space separated representation; Parametric modeling","Sciences de l'ingénieur||Sciences de l'ingénieur","Advanced separated spatial representations for hardly separable domains","Article dans une revue avec comité de lecture","Internationale",,,,,"2020-01-01","2020-01-01",,,,,"Computer Methods in Applied Mechanics and Engineering",,,"Pages 802-819","Oui",,,"Volume 354,","true","newSubmission","aut","2019-07-10T10:07:08Z",,"hal-02178960","accept","true",,"1",
"ed76b6b7-7db1-443d-9818-5d9bbd01e6ec","10985/13599",,"OTHMAN, Ramzi||AMMAR, Amine||ALMITANI, Khalid H.","2023","2023","2020",,,"Ground-borne vibrations are disturbing to human beings. In order to model and reduce these vibrations, the calculation of the harmonic Green’s-functions of the soil is highly required since the most effective numerical solution to predict ground-borne vibration is to couple the finite-element and the boundary-element methods. In this work, we elaborate a direct space-frequency formulation that is especially suitable of material exhibiting visco-elastic behavior. Moreover, an original formulation of the Proper Generalized Decomposition (PGD) reduction technique was undertaken in the frequency-space domain. This new approach highly shortens time computing costs. It is mainly valuable when a parametric study is concerned. Moreover, the PGD resolution allows providing an off-line solution, thus, the solution is calculated only once.","King Abdulaziz University, Jeddah, grant No. (D1439-40-135).","10.1016/j.finel.2020.103419",,"0168-874X","http://hdl.handle.net/10985/23274","en","Centre de Angers","Elsevier BV",,"Post-print","CC BY-ND","Applied Mathematics||Computer Graphics and Computer-Aided Design||General Engineering||Analysis","Sciences de l'ingénieur","Reduced modelling computation of layered soil's harmonic green functions","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,,"Finite Elements in Analysis and Design",,,"103419","Oui",,,"177","true",,"aut||aut||aut",,,,"unsent",,,,"crossref"
"4f34f100-4d32-453e-9e66-08f9fb39d0bf","10985/191||10985/13599",,"BAO, Jianhong||HEYD, Rodolphe||REGNIER, Gilles||AMMAR, Amine||PEIXINHO, Jorge","2024",,"2023",,,"This paper reports the results of an experimental investigation of graphene particle suspensions in lubricating oil, ethylene glycol and glycerol-based fluids. Graphene particles of different specific surface area show variation in the viscosity depending on the shear rate and the temperature. The lubricating effect, e.g., reduction in the viscosity compared to the base fluid, is observed for the concentration (below 0.4 mass%) in lubricating oil and glycerol. In the range of parameters studied (e.g., concentration below 1 mass% and temperature up to 80 °C), the activation energy slightly decreases. The enhancement of viscosity with graphene volume fraction is larger for ethylene glycol. Graphical abstract: [Figure not available: see fulltext.] © 2023, Akadémiai Kiadó, Budapest, Hungary.",,"10.1007/s10973-023-12498-2","1588-2926","1388-6150","http://hdl.handle.net/10985/24943","en","Centre de Angers||Centre de Paris","Springer Science and Business Media LLC",,"Post-print","Pas de Licence CC","Physical and Theoretical Chemistry||Condensed Matter Physics||Polymers and Plastics||Materials Chemistry||Graphene||Viscosity||Lubricating oil||Ethylene glycol||Glycerol","Sciences de l'ingénieur||Chimie: Matériaux","Viscosity of graphene in lubricating oil, ethylene glycol and glycerol","Article dans une revue avec comité de lecture","Internationale",,,,,"2024-03-09","2024-03-09",,"crossref",,"21","Journal of Thermal Analysis and Calorimetry",,"10985/13599","11455-11465","Oui",,,"148","true","newSubmission","aut||aut||aut||aut||aut","2024-03-22T14:29:56Z",,"hal-04517417","accept","true",,"1","crossref"
"32100021-ab7a-4764-bb4b-434caeaaef38","10985/191||10985/13599||10985/189",,"OUTEIRO, José||CHENG, Wenyu||CHINESTA, Francisco||AMMAR, Amine","2022","2022","2022",,,"Ti-6Al-4V titanium is considered a difficult-to-cut material used in critical applications in the aerospace industry requiring high reliability levels. An appropriate selection of cutting conditions can improve the machinability of this alloy and the surface integrity of the machined surface, including the generation of compressive residual stresses. In this paper, orthogonal cutting tests of Ti-6Al-4V titanium were performed using coated and uncoated tungsten carbide tools. Suitable design of experiments (DOE) was used to investigate the influence of the cutting conditions (cutting speed Vc, uncut chip thickness h, tool rake angle γn, and the cutting edge radius rn) on the forces, chip compression ratio, and residual stresses. Due to the time consumed and the high cost of the residual stress measurements, they were only measured for selected cutting conditions of the DOE. Then, the machine learning method based on mathematical regression analysis was applied to predict the residual stresses for other cutting conditions of the DOE. Finally, the optimal cutting conditions that minimize the machining outcomes were determined. The results showed that when increasing the compressive residual stresses at the machined surface by 40%, the rake angle should be increased from negative (−6°) to positive (5°), the cutting edge radius should be doubled (from 16 µm to 30 µm), and the cutting speed should be reduced by 67% (from 60 to 20 m/min).",,"10.3390/jmmp6030058",,"2504-4494","http://hdl.handle.net/10985/22335","en","Centre de Angers||Centre de Cluny||Centre de Paris","MDPI AG",,"Version éditeur","CC BY","Industrial and Manufacturing Engineering||Mechanical Engineering||Mechanics of Materials","Sciences de l'ingénieur","Modelling and Optimization of Machining of Ti-6Al-4V Titanium Alloy Using Machine Learning and Design of Experiments Methods","Article dans une revue avec comité de lecture","Internationale",,,,,,,,"crossref",,"3","Journal of Manufacturing and Materials Processing",,"10985/13599||10985/189","58","Oui",,,"6","true","newSubmission","aut||aut||aut||aut","2022-07-19T08:45:13Z",,"hal-03727274","accept","true",,"1","crossref"
