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http://hdl.handle.net/10985/8256
Discrete Element Method, a Tool to Investigate Complex Material Behaviour in Material Forming
IORDANOFF, Ivan; ILIESCU, Daniel; CHARLES, Jean-Luc; NEAUPORT, Jérôme
Discrete Model is based on the description of the physical state (velocity, position, temperature, magnetic moment, electric potential ..) of a large number of discrete elements that form the media to be studied. It is not based on a continuous description of the media. Then, it is particularly well adapted to describe media evolution driven by discontinuous phenomena : - multi fracturation problems like abrasion process and composite machining, - description of multi fracturation followed by debris flow like wear study Recently, the use of discrete model has been widened to face problem encountered with complex rheological behavior and/or multi-physical behavior. Multi-physical problems face complex mathematical formulation because of the mixing of different families of differential equations when continuous approach is chosen. With the discrete model, each particle has a physical state and state evolution is due to local physical particle interaction: it is often much simple to write. Some attempt to study complex multi-physical problems has been recently presented: - thermal study of a contact and how dissymmetry appears in an apparently symmetrical problem, - study of Friction Stir Welding. This work outlines how discrete element model can be a useful tool in the simulation of material forming. Example is given on abrasion process and machining of composite.
Fri, 01 Jan 2010 00:00:00 GMThttp://hdl.handle.net/10985/82562010-01-01T00:00:00ZIORDANOFF, IvanILIESCU, DanielCHARLES, Jean-LucNEAUPORT, JérômeDiscrete Model is based on the description of the physical state (velocity, position, temperature, magnetic moment, electric potential ..) of a large number of discrete elements that form the media to be studied. It is not based on a continuous description of the media. Then, it is particularly well adapted to describe media evolution driven by discontinuous phenomena : - multi fracturation problems like abrasion process and composite machining, - description of multi fracturation followed by debris flow like wear study Recently, the use of discrete model has been widened to face problem encountered with complex rheological behavior and/or multi-physical behavior. Multi-physical problems face complex mathematical formulation because of the mixing of different families of differential equations when continuous approach is chosen. With the discrete model, each particle has a physical state and state evolution is due to local physical particle interaction: it is often much simple to write. Some attempt to study complex multi-physical problems has been recently presented: - thermal study of a contact and how dissymmetry appears in an apparently symmetrical problem, - study of Friction Stir Welding. This work outlines how discrete element model can be a useful tool in the simulation of material forming. Example is given on abrasion process and machining of composite.Tensile response of the muscle-tendon complex using discrete element model
http://hdl.handle.net/10985/8765
Tensile response of the muscle-tendon complex using discrete element model
ROUX, Anthony; LECOMPTE, Jennyfer; GRAS, Laure-Lise; LAPORTE, Sébastien; IORDANOFF, Ivan
Tear of the muscle-tendon complex (MTC) is one of the main causes of sport injuries (De Labareyre et al. 2005). However, the mechanisms leading to such injury are still unclear (Uchiyama et al. 2011). Before modeling the tear of the MTC, its behavior in tensile test will be first studied. The MTC is a multi-scale, non isotropic and non continuous structure that is composed of numerous fascicles gathered together in a conjunctive sheath (epimysium). Many MTC models use the Finite Element Method (FEM) (Bosboom et al. 2001) to simulate MTC’s behavior as a hyperviscoelastic material. The Discrete Element Method (DEM) used for modeling composite materials (Iliescu et al. 2010) could be adapted to fibrous materials as the MTC. Compared to FEM, the DEM could allow to capture the complex behavior of a material with a simple discretization scheme in terms of concept and implementation as well as to understand the influence of fibers’ orientation on the MTC behavior. The aim of this study was to obtain the force/displacement relationship during a numerical tensile test of a pennate muscle model with DEM.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/87652014-01-01T00:00:00ZROUX, AnthonyLECOMPTE, JennyferGRAS, Laure-LiseLAPORTE, SébastienIORDANOFF, IvanTear of the muscle-tendon complex (MTC) is one of the main causes of sport injuries (De Labareyre et al. 2005). However, the mechanisms leading to such injury are still unclear (Uchiyama et al. 2011). Before modeling the tear of the MTC, its behavior in tensile test will be first studied. The MTC is a multi-scale, non isotropic and non continuous structure that is composed of numerous fascicles gathered together in a conjunctive sheath (epimysium). Many MTC models use the Finite Element Method (FEM) (Bosboom et al. 2001) to simulate MTC’s behavior as a hyperviscoelastic material. The Discrete Element Method (DEM) used for modeling composite materials (Iliescu et al. 2010) could be adapted to fibrous materials as the MTC. Compared to FEM, the DEM could allow to capture the complex behavior of a material with a simple discretization scheme in terms of concept and implementation as well as to understand the influence of fibers’ orientation on the MTC behavior. The aim of this study was to obtain the force/displacement relationship during a numerical tensile test of a pennate muscle model with DEM.Implementation of a Discrete Element Method for the space-time modeling of loading in the case of a soft shock: qualitative approach
http://hdl.handle.net/10985/8650
Implementation of a Discrete Element Method for the space-time modeling of loading in the case of a soft shock: qualitative approach
DUPLESSIS KERGOMARD, Yann; DAU, Frédéric; IORDANOFF, Ivan
The aim of this study is to modelize the space-time loading induced on a target by a deformable impactor, in the case of a ”soft” shock.The originality of this work resides in the use of discrete elements to model the behaviour of the impactor, where large displacements an ddeformations can occur .A qualitative analysis is then developed to describe the changes in load applied to the target, as a function of the parameters relevant to such a shock.
Sat, 01 Jan 2011 00:00:00 GMThttp://hdl.handle.net/10985/86502011-01-01T00:00:00ZDUPLESSIS KERGOMARD, YannDAU, FrédéricIORDANOFF, IvanThe aim of this study is to modelize the space-time loading induced on a target by a deformable impactor, in the case of a ”soft” shock.The originality of this work resides in the use of discrete elements to model the behaviour of the impactor, where large displacements an ddeformations can occur .A qualitative analysis is then developed to describe the changes in load applied to the target, as a function of the parameters relevant to such a shock.The proper generalized decomposition for the simulation of delamination using cohesive zone model
http://hdl.handle.net/10985/8491
The proper generalized decomposition for the simulation of delamination using cohesive zone model
METOUI, Sondes; PRULIERE, Etienne; AMMAR, Amine; DAU, Frédéric; IORDANOFF, Ivan
The use of cohesive zone models is an efficient way to treat the damage, especially when the crack path is known a priori. This is the case in the modeling of delamination in composite laminates. However, the simulations using cohesive zone models are expensive in a computational point of view. When using implicit time integration scheme or when solving static problems, the non-linearity related to the cohesive model requires many iterations before reaching convergence. In explicit approaches, the time step stability condition also requires an important number of iterations. In this article, a new approach based on a separated representation of the solution is proposed. The Proper Generalized Decomposition is used to build the solution. This technique, coupled with a cohesive zone model, allows a significant reduction of the computational cost. The results approximated with the PGD are very close to the ones obtained using the classical finite element approach.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/84912014-01-01T00:00:00ZMETOUI, SondesPRULIERE, EtienneAMMAR, AmineDAU, FrédéricIORDANOFF, IvanThe use of cohesive zone models is an efficient way to treat the damage, especially when the crack path is known a priori. This is the case in the modeling of delamination in composite laminates. However, the simulations using cohesive zone models are expensive in a computational point of view. When using implicit time integration scheme or when solving static problems, the non-linearity related to the cohesive model requires many iterations before reaching convergence. In explicit approaches, the time step stability condition also requires an important number of iterations. In this article, a new approach based on a separated representation of the solution is proposed. The Proper Generalized Decomposition is used to build the solution. This technique, coupled with a cohesive zone model, allows a significant reduction of the computational cost. The results approximated with the PGD are very close to the ones obtained using the classical finite element approach.The GranOO workbench, a new tool for developing discrete element simulations, and its application to tribological problems
http://hdl.handle.net/10985/9375
The GranOO workbench, a new tool for developing discrete element simulations, and its application to tribological problems
ANDRE, Damien; CHARLES, Jean-Luc; IORDANOFF, Ivan; NEAUPORT, Jérôme
Discrete models are based on the descriptions of the physical states (e.g., velocity, position, temperature, magnetic momenta and electric potential) of a large number of discrete elements that form the media under study. These models are not based on a continuous description of the media. Thus, the models are particularly well adapted to describe the evolution of media driven by discontinuous phenomena such as multi-fracturation followed by debris flow as occurs in wear studies. Recently, the use of discrete models has been widened to face problems of complex rheological behaviors and/or multi-physical behaviors. Multi-physical problems involves complex mathematical formulations because of the combination of different families of differential equations when a continuous approach is chosen. These formulas are often much simpler to express in discrete models, in which each particle has a physical state and the evolution of that state is due to local physical interactions among particles. Since the year 2000, this method has been widely applied to the study of tribological problems including wear (Fillot et al., 2007) [1], the thermo-mechanical behavior of a contact (Richard et al., 2008) [2] and subsurface damage due to surface polishing (Iordanoff et al., 2008) [3]. Recent works have shown how this method can be used to obtain quantitative results (André et al., 2012) [4]. To assist and promote research in this area, a free platform GranOO has been developed under a C++ environment and is distributed under a free GPL license. The primary features of this platform are presented in this paper. In addition, a series of examples that illustrate the main steps to construct a reliable tribological numerical simulation are detailed. The details of this platform can be found at http://www.granoo.org.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/93752014-01-01T00:00:00ZANDRE, DamienCHARLES, Jean-LucIORDANOFF, IvanNEAUPORT, JérômeDiscrete models are based on the descriptions of the physical states (e.g., velocity, position, temperature, magnetic momenta and electric potential) of a large number of discrete elements that form the media under study. These models are not based on a continuous description of the media. Thus, the models are particularly well adapted to describe the evolution of media driven by discontinuous phenomena such as multi-fracturation followed by debris flow as occurs in wear studies. Recently, the use of discrete models has been widened to face problems of complex rheological behaviors and/or multi-physical behaviors. Multi-physical problems involves complex mathematical formulations because of the combination of different families of differential equations when a continuous approach is chosen. These formulas are often much simpler to express in discrete models, in which each particle has a physical state and the evolution of that state is due to local physical interactions among particles. Since the year 2000, this method has been widely applied to the study of tribological problems including wear (Fillot et al., 2007) [1], the thermo-mechanical behavior of a contact (Richard et al., 2008) [2] and subsurface damage due to surface polishing (Iordanoff et al., 2008) [3]. Recent works have shown how this method can be used to obtain quantitative results (André et al., 2012) [4]. To assist and promote research in this area, a free platform GranOO has been developed under a C++ environment and is distributed under a free GPL license. The primary features of this platform are presented in this paper. In addition, a series of examples that illustrate the main steps to construct a reliable tribological numerical simulation are detailed. The details of this platform can be found at http://www.granoo.org.A new C++ workbench to develop discrete element simulations: GranOO
http://hdl.handle.net/10985/8266
A new C++ workbench to develop discrete element simulations: GranOO
ANDRÉ, Damien; CHARLES, Jean-Luc; IORDANOFF, Ivan
Discrete Model is based on the description of the physical state (velocity, position, temperature, magnetic moment, electric potential ..) of a large number of discrete elements that form the media to be studied. It is not based on a continuous description of the media. Thus, it is particularly well adapted to describe media evolution driven by discontinuous phenomena like the description of multi fracturation followed by debris flow like wear study. Recently, the use of discrete model has been widened to face problem encounteredwith complex rheological behavior and/or multi-physical behavior. Multi-physical problems face complex mathematical formulation because of the mixing of different families of differential equations when continuous approach is chosen. With the discrete model, each particle has a physical state and state evolution is due to local physical particle interaction: it is often much simple to write. To help and promote research in this area, a free platform GranOO has been developed under a C++ environment and is distributed under the GPL license. The main aspect of this platform is presented in this extended abstract and one application is given as example. Details can be found on url www.granoo.org.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/82662013-01-01T00:00:00ZANDRÉ, DamienCHARLES, Jean-LucIORDANOFF, IvanDiscrete Model is based on the description of the physical state (velocity, position, temperature, magnetic moment, electric potential ..) of a large number of discrete elements that form the media to be studied. It is not based on a continuous description of the media. Thus, it is particularly well adapted to describe media evolution driven by discontinuous phenomena like the description of multi fracturation followed by debris flow like wear study. Recently, the use of discrete model has been widened to face problem encounteredwith complex rheological behavior and/or multi-physical behavior. Multi-physical problems face complex mathematical formulation because of the mixing of different families of differential equations when continuous approach is chosen. With the discrete model, each particle has a physical state and state evolution is due to local physical particle interaction: it is often much simple to write. To help and promote research in this area, a free platform GranOO has been developed under a C++ environment and is distributed under the GPL license. The main aspect of this platform is presented in this extended abstract and one application is given as example. Details can be found on url www.granoo.org.Modeling of Magnetorheological Fluids by the Discrete Element Method
http://hdl.handle.net/10985/8258
Modeling of Magnetorheological Fluids by the Discrete Element Method
KARGULEWICZ, Mickaël; IORDANOFF, Ivan; MARRERO, Victor; TICHY, John
Magnetorheological (MR) fluids are fluids whose properties vary in response to an applied magnetic field. Such fluids are typically composed of microscopic iron particles ( 1 20 lm diameter, 20 40% by volume) suspended in a carrier fluid such as mineral oil or water. MR fluids are increasingly proposed for use in various mechanical system applications, many of which fall in the domain of tribology, such as smart dampers and clutches, prosthetic articulations, and controllable polishing fluids. The goal of this study is to present an overview of the topic to the tribology audience, and to develop an MR fluid model from the microscopic point of view using the discrete element method (DEM), with a long range objective to better optimize and understand MR fluid behavior in such tribological applications. As in most DEM studies, inter-particle forces are determined by a force-displacement law and trajectories are calculated using Newton’s second law. In this study, particle magnetization and magnetic interactions between particles have been added to the discrete element code. The global behavior of the MR fluid can be analyzed by examining the time evolution of the ensemble of particles. Microscopically, the known behavior is observed: particles align themselves with the external magnetic field. Macroscopically, averaging over a number of particles and a significant time interval, effective viscosity increases significantly when an external magnetic field is applied. These preliminary results would appear to establish that the DEM is a promising method to study MR fluids at the microscopic and macroscopic scales as an aid to tribological design. [DOI: 10.1115/1.4006021]
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/10985/82582012-01-01T00:00:00ZKARGULEWICZ, MickaëlIORDANOFF, IvanMARRERO, VictorTICHY, JohnMagnetorheological (MR) fluids are fluids whose properties vary in response to an applied magnetic field. Such fluids are typically composed of microscopic iron particles ( 1 20 lm diameter, 20 40% by volume) suspended in a carrier fluid such as mineral oil or water. MR fluids are increasingly proposed for use in various mechanical system applications, many of which fall in the domain of tribology, such as smart dampers and clutches, prosthetic articulations, and controllable polishing fluids. The goal of this study is to present an overview of the topic to the tribology audience, and to develop an MR fluid model from the microscopic point of view using the discrete element method (DEM), with a long range objective to better optimize and understand MR fluid behavior in such tribological applications. As in most DEM studies, inter-particle forces are determined by a force-displacement law and trajectories are calculated using Newton’s second law. In this study, particle magnetization and magnetic interactions between particles have been added to the discrete element code. The global behavior of the MR fluid can be analyzed by examining the time evolution of the ensemble of particles. Microscopically, the known behavior is observed: particles align themselves with the external magnetic field. Macroscopically, averaging over a number of particles and a significant time interval, effective viscosity increases significantly when an external magnetic field is applied. These preliminary results would appear to establish that the DEM is a promising method to study MR fluids at the microscopic and macroscopic scales as an aid to tribological design. [DOI: 10.1115/1.4006021]Simulation de la conduction de la chaleur dans un milieu continu par un modèle éléments discrets
http://hdl.handle.net/10985/8264
Simulation de la conduction de la chaleur dans un milieu continu par un modèle éléments discrets
TERREROS, Inigo; IORDANOFF, Ivan; CHARLES, Jean-Luc
Discrete Element Method (DEM) uses a set of discrete elements in order to describe the material under study. The reason is that originally it was conceived to describe granular materials. Thus is naturally adapted to simulate problems like, for example, dry contact, fracturation and mixing. Nevertheless, modelling of a continuous zone may be useful in some of those problems. In that case, the correct physical behaviour of the continuous zone must be ensured. This work, based on the article by W. L. Vargas [1], explains how to simulate heat conduction through a continuous material using a discrete model of the domain.
Sat, 01 Jan 2011 00:00:00 GMThttp://hdl.handle.net/10985/82642011-01-01T00:00:00ZTERREROS, InigoIORDANOFF, IvanCHARLES, Jean-LucDiscrete Element Method (DEM) uses a set of discrete elements in order to describe the material under study. The reason is that originally it was conceived to describe granular materials. Thus is naturally adapted to simulate problems like, for example, dry contact, fracturation and mixing. Nevertheless, modelling of a continuous zone may be useful in some of those problems. In that case, the correct physical behaviour of the continuous zone must be ensured. This work, based on the article by W. L. Vargas [1], explains how to simulate heat conduction through a continuous material using a discrete model of the domain.Discrete element method, a tool to investigate complex thermo mechanical behaviour: application to friction stir welding
http://hdl.handle.net/10985/9414
Discrete element method, a tool to investigate complex thermo mechanical behaviour: application to friction stir welding
TERREROS, Inigo; IORDANOFF, Ivan; CHARLES, Jean-Luc; COUPARD, Dominique; TCHERNIAEFF, Serge
In material forming or cutting, the contact zone between the tool and the working piece is often very difficult to analyse because of diverse local phenomena. In the special case of FSW, a specific difficulty is the study of material mixing. In this work, the Discrete Element Method is applied as a tool to understand/propose/confirm physical scenarii involved in FSW process. A simple micro behaviour law that takes into account thermal, mechanical and material aspects is proposed and a two dimensional simulation based on this law is presented. The first results show qualitatively good agreement with real nuggets observations. One of the main advantages of DEM approach is the simplicity of the local input law compared with laws proposed at the continuous media mechanics level. Nevertheless, numerical aspect must be improved to carry out three dimensional simulations with reasonable calculation times.
Thu, 01 Jan 2009 00:00:00 GMThttp://hdl.handle.net/10985/94142009-01-01T00:00:00ZTERREROS, InigoIORDANOFF, IvanCHARLES, Jean-LucCOUPARD, DominiqueTCHERNIAEFF, SergeIn material forming or cutting, the contact zone between the tool and the working piece is often very difficult to analyse because of diverse local phenomena. In the special case of FSW, a specific difficulty is the study of material mixing. In this work, the Discrete Element Method is applied as a tool to understand/propose/confirm physical scenarii involved in FSW process. A simple micro behaviour law that takes into account thermal, mechanical and material aspects is proposed and a two dimensional simulation based on this law is presented. The first results show qualitatively good agreement with real nuggets observations. One of the main advantages of DEM approach is the simplicity of the local input law compared with laws proposed at the continuous media mechanics level. Nevertheless, numerical aspect must be improved to carry out three dimensional simulations with reasonable calculation times.3D coupling approach between discrete and continuum models for dynamic simulations (DEM–CNEM)
http://hdl.handle.net/10985/7540
3D coupling approach between discrete and continuum models for dynamic simulations (DEM–CNEM)
JEBAHI, Mohamed; CHARLES, Jean-Luc; DAU, Frédéric; ILLOUL, Lounès; IORDANOFF, Ivan
The coupling between two dissimilar numerical methods presents a major challenge, especially in case of discrete–continuum coupling. The Arlequin approach provides a flexible framework and presents several advantages in comparison to alternative approaches. Many studies have analyzed, in statics, the ingredients of this approach in 1D configurations under several particular conditions. The present study extends the Arlequin parameter studies to incorporate a dynamic behavior using 3D models. Based on these studies, a new 3D coupling method adapted for dynamic simulations is developed. This method couples two 3D codes: DEM-based code and CNEM-based code. The 3D coupling method was applied to several reference dynamics tests. Good results are obtained using this method, compared with the analytical and numerical results of both DEM and CNEM.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/75402013-01-01T00:00:00ZJEBAHI, MohamedCHARLES, Jean-LucDAU, FrédéricILLOUL, LounèsIORDANOFF, IvanThe coupling between two dissimilar numerical methods presents a major challenge, especially in case of discrete–continuum coupling. The Arlequin approach provides a flexible framework and presents several advantages in comparison to alternative approaches. Many studies have analyzed, in statics, the ingredients of this approach in 1D configurations under several particular conditions. The present study extends the Arlequin parameter studies to incorporate a dynamic behavior using 3D models. Based on these studies, a new 3D coupling method adapted for dynamic simulations is developed. This method couples two 3D codes: DEM-based code and CNEM-based code. The 3D coupling method was applied to several reference dynamics tests. Good results are obtained using this method, compared with the analytical and numerical results of both DEM and CNEM.