SAM
https://sam.ensam.eu:443
The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 26 Sep 2021 16:52:25 GMT2021-09-26T16:52:25ZEvaluation of morphological representative sample sizes for nanolayered polymer blends
http://hdl.handle.net/10985/11276
Evaluation of morphological representative sample sizes for nanolayered polymer blends
BIRONEAU, Adrien; DIRRENBERGER, Justin; SOLLOGOUB, Cyrille; MIQUELARD-GARNIER, Guillaume; ROLAND, Sébastien
The size of representative microstructural samples obtained from atomic force microscopy is addressed in this paper. The case of an archetypal one-dimensional nanolayered polymer blend is considered. Image analysis is performed on micrographs obtained through atomic force microscopy, yielding statistical data concerning morphological properties of the material. The variability in terms of microstructural morphology is due to the thermomechanical processing route. The statistical data is used in order to estimate sample size representativity, based on an asymptotic relationship relating the inherent point variance of the indicator function of one material phase to the statistical, size-dependent, ensemble variance of the same function. From the study of nanolayered material systems, the statistical approach was found to be an effective mean for discriminating and characterizing multiple scales of heterogeneity.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/112762016-01-01T00:00:00ZBIRONEAU, AdrienDIRRENBERGER, JustinSOLLOGOUB, CyrilleMIQUELARD-GARNIER, GuillaumeROLAND, SébastienThe size of representative microstructural samples obtained from atomic force microscopy is addressed in this paper. The case of an archetypal one-dimensional nanolayered polymer blend is considered. Image analysis is performed on micrographs obtained through atomic force microscopy, yielding statistical data concerning morphological properties of the material. The variability in terms of microstructural morphology is due to the thermomechanical processing route. The statistical data is used in order to estimate sample size representativity, based on an asymptotic relationship relating the inherent point variance of the indicator function of one material phase to the statistical, size-dependent, ensemble variance of the same function. From the study of nanolayered material systems, the statistical approach was found to be an effective mean for discriminating and characterizing multiple scales of heterogeneity.Towards gigantic RVE sizes for 3D stochastic fibrous networks
http://hdl.handle.net/10985/7983
Towards gigantic RVE sizes for 3D stochastic fibrous networks
DIRRENBERGER, Justin; FOREST, Samuel; JEULIN, Dominique
The size of representative volume element (RVE) for 3D stochastic fibrous media is investigated. A statistical RVE size determination method is applied to a specific model of random microstructure: Poisson fibers. The definition of RVE size is related to the concept of integral range. What happens in microstructures exhibiting an infinite integral range? Computational homogenization for thermal and elastic properties is performed through finite elements, over hundreds of realizations of the stochastic microstructural model, using uniform and mixed boundary conditions. The generated data undergoes statistical treatment, from which gigantic RVE sizes emerge. The method used for determining RVE sizes was found to be operational, even for pathological media, i.e., with infinite integral range, interconnected percolating porous phase and infinite contrast of properties
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/79832014-01-01T00:00:00ZDIRRENBERGER, JustinFOREST, SamuelJEULIN, DominiqueThe size of representative volume element (RVE) for 3D stochastic fibrous media is investigated. A statistical RVE size determination method is applied to a specific model of random microstructure: Poisson fibers. The definition of RVE size is related to the concept of integral range. What happens in microstructures exhibiting an infinite integral range? Computational homogenization for thermal and elastic properties is performed through finite elements, over hundreds of realizations of the stochastic microstructural model, using uniform and mixed boundary conditions. The generated data undergoes statistical treatment, from which gigantic RVE sizes emerge. The method used for determining RVE sizes was found to be operational, even for pathological media, i.e., with infinite integral range, interconnected percolating porous phase and infinite contrast of propertiesClassification of building systems for concrete 3D printing
http://hdl.handle.net/10985/12037
Classification of building systems for concrete 3D printing
DUBALLET, Romain; BAVEREL, Olivier; DIRRENBERGER, Justin
In the present paper, a study is conducted on building systems associated with concrete extrusion-based additive manufacturing techniques. Specific parameters are highlighted - concerning scale, environment, support, and assembly strategies - and a classification method is introduced. The objective is to explicitly characterise construction systems based on such printing processes. A cartography of the different approaches and subsequent robotic complexity is proposed. The state of the art gathered from the literature is mapped thanks to this classification. It appears that the disruption potential brought by concrete 3D printing has not been fully embraced yet.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/120372017-01-01T00:00:00ZDUBALLET, RomainBAVEREL, OlivierDIRRENBERGER, JustinIn the present paper, a study is conducted on building systems associated with concrete extrusion-based additive manufacturing techniques. Specific parameters are highlighted - concerning scale, environment, support, and assembly strategies - and a classification method is introduced. The objective is to explicitly characterise construction systems based on such printing processes. A cartography of the different approaches and subsequent robotic complexity is proposed. The state of the art gathered from the literature is mapped thanks to this classification. It appears that the disruption potential brought by concrete 3D printing has not been fully embraced yet.From Architectured Materials to the Development of Large-scale Additive Manufacturing
http://hdl.handle.net/10985/12035
From Architectured Materials to the Development of Large-scale Additive Manufacturing
DIRRENBERGER, Justin
Architectured materials are a rising class of materials that bring new possibilities in terms of functional properties, filling the gaps and pushing the limits of Ashby’s materials performance maps. Capitalizing on the concepts of architectured materials, explorations of the potential applications of large-scale 3D printing techniques to civil engineering structures were recently implemented in the DEMOCRITE project.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/120352016-01-01T00:00:00ZDIRRENBERGER, JustinArchitectured materials are a rising class of materials that bring new possibilities in terms of functional properties, filling the gaps and pushing the limits of Ashby’s materials performance maps. Capitalizing on the concepts of architectured materials, explorations of the potential applications of large-scale 3D printing techniques to civil engineering structures were recently implemented in the DEMOCRITE project.Design of Space Truss Based Insulating Walls for Robotic Fabrication in Concrete
http://hdl.handle.net/10985/12038
Design of Space Truss Based Insulating Walls for Robotic Fabrication in Concrete
DUBALLET, Romain; BAVEREL, Olivier; DIRRENBERGER, Justin
This work focuses on the design of ultra-light concrete walls for individual or collective housing, the normative context being constrained masonry. It is stated that current block work building is very inefficient in terms of quantity of concrete used for cinderblocks and mortar joints, and with regards to thermal insulation. Here is proposed a robotic manufacturing technique based on mortar extrusion that allows producing more efficient walls. First we present the fabrication concept, then design criteria for such objects. In the last section we show a comparative study on different geometries. We conclude with a discussion on the performances of this proposed building system.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/120382018-01-01T00:00:00ZDUBALLET, RomainBAVEREL, OlivierDIRRENBERGER, JustinThis work focuses on the design of ultra-light concrete walls for individual or collective housing, the normative context being constrained masonry. It is stated that current block work building is very inefficient in terms of quantity of concrete used for cinderblocks and mortar joints, and with regards to thermal insulation. Here is proposed a robotic manufacturing technique based on mortar extrusion that allows producing more efficient walls. First we present the fabrication concept, then design criteria for such objects. In the last section we show a comparative study on different geometries. We conclude with a discussion on the performances of this proposed building system.A complete description of bi-dimensional anisotropic strain-gradient elasticity
http://hdl.handle.net/10985/9885
A complete description of bi-dimensional anisotropic strain-gradient elasticity
AUFFRAY, Nicolas; DIRRENBERGER, Justin; ROSI, Giuseppe
In the present paper spaces of fifth-order tensors involved in bidimensional strain gradient elasticity are studied. As a result complete sets of matrices representing these tensors in each one of their anisotropic system are provided. This paper completes and ends some previous studies on the subject providing a complete description of the anisotropic bidimensional strain gradient elasticity. It is proved that this behavior is divided into 14 non equivalent anisotropic classes, 8 of them being isotropic for classical elasticity. The classification and matrix representations of the acoustical gyrotropic tensor are also provided, these results may find interesting applications to the study of waves propagation in dispersive micro-structured-media.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/98852015-01-01T00:00:00ZAUFFRAY, NicolasDIRRENBERGER, JustinROSI, GiuseppeIn the present paper spaces of fifth-order tensors involved in bidimensional strain gradient elasticity are studied. As a result complete sets of matrices representing these tensors in each one of their anisotropic system are provided. This paper completes and ends some previous studies on the subject providing a complete description of the anisotropic bidimensional strain gradient elasticity. It is proved that this behavior is divided into 14 non equivalent anisotropic classes, 8 of them being isotropic for classical elasticity. The classification and matrix representations of the acoustical gyrotropic tensor are also provided, these results may find interesting applications to the study of waves propagation in dispersive micro-structured-media.Large-scale 3D printing of ultra-high performance concrete – a new processing route for architects and builders
http://hdl.handle.net/10985/11275
Large-scale 3D printing of ultra-high performance concrete – a new processing route for architects and builders
GOSSELIN, Clément; DUBALLET, Romain; ROUX, Philippe; GAUDILLIÈRE, Nadja; DIRRENBERGER, Justin; MOREL, Philippe
In the present paper a new additive manufacturing processing route is introduced for ultra-high performance concrete. Interdisciplinary work involving materials science, computation, robotics, architecture and design resulted in the development of an innovative way of 3D printing cementitious materials. The 3D printing process involved is based on a FDM-like technique, in the sense that a material is deposited layer by layer through an extrusion printhead mounted on a 6-axis robotic arm. The mechanical properties of 3D printed materials are assessed. The proposed technology succeeds in solving many of the problems that can be found in the literature. Most notably, this process allows the production of 3D large-scale complex geometries, without the use of temporary supports, as opposed to 2.5D examples found in the literature for concrete 3D printing. Architectural cases of application are used as examples in order to demonstrate the potentialities of the technology. Two structural elements were produced and constitute some of the largest 3D printed concrete parts available until now. Multi-functionality was enabled for both structural elements by taking advantage of the complex geometry which can be achieved using our technology for large-scale additive manufacturing.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/112752016-01-01T00:00:00ZGOSSELIN, ClémentDUBALLET, RomainROUX, PhilippeGAUDILLIÈRE, NadjaDIRRENBERGER, JustinMOREL, PhilippeIn the present paper a new additive manufacturing processing route is introduced for ultra-high performance concrete. Interdisciplinary work involving materials science, computation, robotics, architecture and design resulted in the development of an innovative way of 3D printing cementitious materials. The 3D printing process involved is based on a FDM-like technique, in the sense that a material is deposited layer by layer through an extrusion printhead mounted on a 6-axis robotic arm. The mechanical properties of 3D printed materials are assessed. The proposed technology succeeds in solving many of the problems that can be found in the literature. Most notably, this process allows the production of 3D large-scale complex geometries, without the use of temporary supports, as opposed to 2.5D examples found in the literature for concrete 3D printing. Architectural cases of application are used as examples in order to demonstrate the potentialities of the technology. Two structural elements were produced and constitute some of the largest 3D printed concrete parts available until now. Multi-functionality was enabled for both structural elements by taking advantage of the complex geometry which can be achieved using our technology for large-scale additive manufacturing.Calorimetric Studies and Self-Heating Measurements for a Dual-Phase Steel Under Ultrasonic Fatigue Loading
http://hdl.handle.net/10985/12040
Calorimetric Studies and Self-Heating Measurements for a Dual-Phase Steel Under Ultrasonic Fatigue Loading
TORABIAN, Noushin; FAVIER, Véronique; ZIAEI-RAD, Saeed; DIRRENBERGER, Justin; ADAMSKI, Frédéric; RANC, Nicolas
The objective of the present research is to study the self-heating behavior of a dual-phase (DP) steel under ultrasonic fatigue loading and to investigate the effect of frequency on intrinsic heat dissipation of the material. The steel studied in this work is DP600 commercial DP steel. Fatigue tests were conducted using an ultrasonic fatigue machine at a testing frequency of 20 kHz with flat specimens. An infrared camera was used to measure the mean temperature evolution during the tests. A specific form of heat diffusion equation was adopted in this work to calculate the heat dissipation per cycle from temperature measurements. The variation of this dissipation versus stress amplitude in cyclic loading was also studied.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/120402016-01-01T00:00:00ZTORABIAN, NoushinFAVIER, VéroniqueZIAEI-RAD, SaeedDIRRENBERGER, JustinADAMSKI, FrédéricRANC, NicolasThe objective of the present research is to study the self-heating behavior of a dual-phase (DP) steel under ultrasonic fatigue loading and to investigate the effect of frequency on intrinsic heat dissipation of the material. The steel studied in this work is DP600 commercial DP steel. Fatigue tests were conducted using an ultrasonic fatigue machine at a testing frequency of 20 kHz with flat specimens. An infrared camera was used to measure the mean temperature evolution during the tests. A specific form of heat diffusion equation was adopted in this work to calculate the heat dissipation per cycle from temperature measurements. The variation of this dissipation versus stress amplitude in cyclic loading was also studied.Thermal response of DP600 dual-phase steel under ultrasonic fatigue loading
http://hdl.handle.net/10985/11247
Thermal response of DP600 dual-phase steel under ultrasonic fatigue loading
TORABIAN, Noushin; FAVIER, Véronique; ZIAEI-RAD, Saeed; DIRRENBERGER, Justin; ADAMSKI, Frédéric; RANC, Nicolas
The present work employed in situ infrared thermography to investigate the thermal response and dissipative mechanisms of a dual-phase steel under ultrasonic tension-compression fatigue testing. A classical thermal response occurred for stress amplitudes below 247 MPa but an abnormal thermal response was observed for stress amplitudes above 247 MPa, in that the temperature stabilized after a steep increase of up to 350 °C. The mean dissipated energy per cycle was estimated based on temperature measurements using the heat diffusion equation. The relationship between the mean dissipated energy per cycle and the stress amplitude was studied, and mechanisms related to the observed thermal response were discussed.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/112472016-01-01T00:00:00ZTORABIAN, NoushinFAVIER, VéroniqueZIAEI-RAD, SaeedDIRRENBERGER, JustinADAMSKI, FrédéricRANC, NicolasThe present work employed in situ infrared thermography to investigate the thermal response and dissipative mechanisms of a dual-phase steel under ultrasonic tension-compression fatigue testing. A classical thermal response occurred for stress amplitudes below 247 MPa but an abnormal thermal response was observed for stress amplitudes above 247 MPa, in that the temperature stabilized after a steep increase of up to 350 °C. The mean dissipated energy per cycle was estimated based on temperature measurements using the heat diffusion equation. The relationship between the mean dissipated energy per cycle and the stress amplitude was studied, and mechanisms related to the observed thermal response were discussed.Isogeometric shape optimization of smoothed petal auxetic structures via computational periodic homogenization
http://hdl.handle.net/10985/12036
Isogeometric shape optimization of smoothed petal auxetic structures via computational periodic homogenization
WANG, Zhen-Pei; POH, Leong Hien; DIRRENBERGER, Justin; ZHU, Yilin; FOREST, Samuel
An important feature that drives the auxetic behaviour of the star-shaped auxetic structures is the hinge-functional connection at the vertex connections. This feature poses a great challenge for manufacturing and may lead to significant stress concentrations. To overcome these problems, we introduced smoothed petal-shaped auxetic structures, where the hinges are replaced by smoothed connections. To accommodate the curved features of the petal-shaped auxetics, a parametrisation modelling scheme using multiple NURBS patches is proposed. Next, an integrated shape design frame work using isogeometric analysis is adopted to improve the structural performance. To ensure a minimum thickness for each member, a geometry sizing constraint is imposed via piece-wise bounding polynomials. This geometry sizing constraint, in the context of isogeometric shape optimization, is particularly interesting due to the non-interpolatory nature of NURBS basis. The effective Poisson ratio is used directly as the objective function, and an adjoint sensitivity analysis is carried out. The optimized designs – smoothed petal auxetic structures – are shown to achieve low negative Poisson’s ratios, while the difficulties of manufacturing the hinges are avoided. For the case with six petals, an in-plane isotropy is achieved.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/120362017-01-01T00:00:00ZWANG, Zhen-PeiPOH, Leong HienDIRRENBERGER, JustinZHU, YilinFOREST, SamuelAn important feature that drives the auxetic behaviour of the star-shaped auxetic structures is the hinge-functional connection at the vertex connections. This feature poses a great challenge for manufacturing and may lead to significant stress concentrations. To overcome these problems, we introduced smoothed petal-shaped auxetic structures, where the hinges are replaced by smoothed connections. To accommodate the curved features of the petal-shaped auxetics, a parametrisation modelling scheme using multiple NURBS patches is proposed. Next, an integrated shape design frame work using isogeometric analysis is adopted to improve the structural performance. To ensure a minimum thickness for each member, a geometry sizing constraint is imposed via piece-wise bounding polynomials. This geometry sizing constraint, in the context of isogeometric shape optimization, is particularly interesting due to the non-interpolatory nature of NURBS basis. The effective Poisson ratio is used directly as the objective function, and an adjoint sensitivity analysis is carried out. The optimized designs – smoothed petal auxetic structures – are shown to achieve low negative Poisson’s ratios, while the difficulties of manufacturing the hinges are avoided. For the case with six petals, an in-plane isotropy is achieved.