Michel Bellet | PSL - Academia.edu (original) (raw)
Papers by Michel Bellet
HAL (Le Centre pour la Communication Scientifique Directe), Feb 26, 2017
Spark Plasma Sintering (SPS) is a process belonging to the powder metallurgy family. It consists ... more Spark Plasma Sintering (SPS) is a process belonging to the powder metallurgy family. It consists in applying simultaneously a load and a high intensity pulsed direct current on graphite tools containing powder to sinter this latter. The originality of this study lies on the in-situ SPS compression creep tests performed on TiAl 48-2-2 dense and porous samples, completed by SPS powder densification to established the creep law of this material. Once determined, it is then used in a fully-coupled simulation tool to predict temperature field and density gradient within the samples. The experimental relative density map will be presented and the correlation with the numerical model will be analyzed, both on simple and complex shape specimens. The evolution of the microstructure during creep test as well as after densification of a complex part will be presented and correlation with numerically assessed temperature field will be discussed.
A 3D finite element model is developed to study heat exchange during the selective laser melting ... more A 3D finite element model is developed to study heat exchange during the selective laser melting (SLM) process. The level set functions are used to track the interface between the constructed workpiece and non-melted powder, and interface between the gas domain and the successive powder bed layers In order to reach the simulation in macroscopic scale of real part geometries in a reasonable simulation time, the energy input and the formation of the additive deposit are simplified by considering them at the scale of an entire layer or fraction of each layer. The layer fractions are identified directly from a description (e.g. using G-code) of the global laser scan plan of the part construction. Each fraction is heated during a time interval corresponding to the exposure time to the laser beam, and then cooled down during a time interval equal to the scan time of the laser beam over the considered layer fraction. The global heat transfer through the part under additive construction and the powder material non-exposed to the laser beam is simulated. To reduce the computational cost, mesh-adaptation is adopted during the construction process. The proposed model is able to predict the temperature distribution and evolution in the constructed workpiece and non-melted powder during the SLM process at the macroscale, for parts made of complex geometry. Application is shown for a nickel based material (IN718), but the numerical model can be easily extended to other materials by using their data sets.
HAL (Le Centre pour la Communication Scientifique Directe), May 13, 2016
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Oct 5, 2021
HAL (Le Centre pour la Communication Scientifique Directe), May 30, 2018
HAL (Le Centre pour la Communication Scientifique Directe), Jun 17, 2019
Item Description: ASM International. Hardback. Book Condition: new. BRAND NEW, Modelling in Weldi... more Item Description: ASM International. Hardback. Book Condition: new. BRAND NEW, Modelling in Welding, Hot Powder Forming and Casting, Lennart Karlsson, This reference work provides thorough coverage of theoretical foundations of the thermomechanical modeling of welding, hot powder forming, and casting processes, which can also be applied to modeling of the heat treatment and forging of solids. Information on finite element modeling methods will assist design engineers in taking manufacturing processes into consideration to minimize residual stresses and deformation in the design of mechanical components. Contents: Thermomechanical Modeling Thermal Modeling of Welds Mechanical Modeling of Welding and Residual Stresses in Welds Metallurgical and Mechanical Consequences of Phase Transformations in Numerical Simulations of Welding Processes Predicting and Measuring Methods of Two- and Three-Dimensional Residual Stresses by Using Inherent Strain as a Parameter Hot Isostatic Pressing Hot Powder Forging And More. Bookseller Inventory # B9780871706164
HAL (Le Centre pour la Communication Scientifique Directe), Jun 27, 2016
International audienceThe standard riveting process used for joining stiffeners (AA 7075) to pane... more International audienceThe standard riveting process used for joining stiffeners (AA 7075) to panels (AA 2024) in aeronautic industry has a detrimental effect on the weight of planes. Friction stir welding (FSW) process is seen as an interesting option and a promising alternative process to lighten aircraft structure. However the mechanical properties in these grades are linked to structural hardening due to the solid state development of fine and densely distributed precipitates. FSW processes are known to affect these precipitates and the final properties of the welds. Thus the estimation of precipitate evolutions is of prime importance in order to deliver reliable welds to the aircraft industry. A time-efficient solid-state precipitation modelling based on a reliable thermodynamic description has been developed in order to predict the precipitate distribution and the related mechanical properties. At a micro scale, a particle size distribution approach (PSD) [1] is proposed for multi-components alloys to predict the nucleation, growth, dissolution and coarsening of both stable and metastable phases. The model is coupled to thermodynamic computations [2] in order to determine precipitate/matrix equilibrium compositions and associated growth velocity. This microstructural model is applied on a AA 2024 aluminium alloy in order to model both stable (S-phase) and metastable (GPB zones) phases. A DSC (Differential Scanning Calorimetry) calibration procedure has been developed to determine the nucleation parameters (Fig. 1 a). At a larger scale, a macro-structural model is used to define precisely the thermo-mechanical evolutions of the metal parts and thermal evolution inside welds [3]. Then, it is possible to couple the micro/macro models in order to define precisely the precipitate evolutions in nuggets, TMAZ and HAZ domains leading to heterogeneous mechanical properties (Fig. 1 b). The final mechanical properties are presented and discussed.[1] V. Legrand, Modélisation des processus de précipitation et prédiction des propriétés mécaniques résultantes dans les alliages d’aluminium à durcissement structural – Application au soudage par Friction Malaxage (FSW) de tôles AA2024, Doct. MinesParisTech, 2015[2]TCAL3, TCS Al-based alloys thermodynamic database, TC software AB (Stockholm, Sweden), 2014.[3]S. Gastebois, Simulation numérique 3D du FSW à l’aide d'une formulation ALE, Doct. Mines Paristech, 201
HAL (Le Centre pour la Communication Scientifique Directe), Jun 7, 2009
IOP conference series, 2023
In the present work, a methodology to identify parameters of an elastic viscoplastic behaviour la... more In the present work, a methodology to identify parameters of an elastic viscoplastic behaviour law is presented. Orthotropic elasticity and Hill48 plastic anisotropy for as-cast CMSX-4 are considered. In order to obtain the corresponding parameters by inverse analysis, an experimental database is built by tensile/relaxation tests at constant temperatures between 800°C and 1200°C on specimens oriented along <001>, <110> and <111> directions at different strain rates. Tests are performed with a resistive heating machine, using infrared thermography and digital image correlation. The obtained mechanical behaviour is very dependent on specimen orientation at all tested temperatures. Recrystallization behaviour is also very relevant to the specimens’ orientation.
HAL (Le Centre pour la Communication Scientifique Directe), May 11, 2022
HAL (Le Centre pour la Communication Scientifique Directe), Jun 20, 2022
HAL (Le Centre pour la Communication Scientifique Directe), Mar 14, 2006
HAL (Le Centre pour la Communication Scientifique Directe), Oct 25, 2017
The objective of this work is to develop new numerical simulation techniques in meso- and macro-s... more The objective of this work is to develop new numerical simulation techniques in meso- and macro-scale to optimize the LBM process. The two scale models are under a level-set framework. A meso-scale simulation focuses on the laser interaction with the powder bed and subsequent melting and solidification. Thermomechanical finite element (FE) modelling is conducted at the scale of material deposition, and addresses the melting of the powder bed, the hydrodynamics of the fusion zone and the formation of local thermal stresses in the wake of the laser. A macro-scale simulation focuses on part construction. This thermomechanical finite element model addresses heat exchange and stress formation at the scale of the part by considering the non-exposed powder. In order to reach reasonable simulation time for industrial parts, the energy input and the formation of the additive deposit are simplified by considering them at the scale of an entire layer or fractions of each layer.
HAL (Le Centre pour la Communication Scientifique Directe), May 17, 2017
A 3D finite element model is developed to study heat exchange during the selective laser melting ... more A 3D finite element model is developed to study heat exchange during the selective laser melting (SLM) process. The level set functions are used to track the interface between the constructed workpiece and non-melted powder, and interface between the gas domain and the successive powder bed layers In order to reach the simulation in macroscopic scale of real part geometries in a reasonable simulation time, the energy input and the formation of the additive deposit are simplified by considering them at the scale of an entire layer or fraction of each layer. The layer fractions are identified directly from a description (e.g. using G-code) of the global laser scan plan of the part construction. Each fraction is heated during a time interval corresponding to the exposure time to the laser beam, and then cooled down during a time interval equal to the scan time of the laser beam over the considered layer fraction. The global heat transfer through the part under additive construction and the powder material non-exposed to the laser beam is simulated. To reduce the computational cost, mesh-adaptation is adopted during the construction process. The proposed model is able to predict the temperature distribution and evolution in the constructed workpiece and non-melted powder during the SLM process at the macroscale, for parts made of complex geometry. Application is shown for a nickel based material (IN718), but the numerical model can be easily extended to other materials by using their data sets.
IOP Conference Series: Materials Science and Engineering
Laser Powder Bed Fusion (L-PBF) is seen as a process of interest by aeronautical industry to deve... more Laser Powder Bed Fusion (L-PBF) is seen as a process of interest by aeronautical industry to develop new engine components. Nevertheless, the reliability and durability of parts produced by L-PBF depend on the possibility to suppress the occurrence of defects. Among them, hot cracking represents a key issue. These cracks are due to the liquid film remaining between grains at the end of the solidification stage combined with stresses and strains endured by the mushy domain. A microsegregation model providing relevant prediction of the solidification path during L-PBF is thus required for coupling with a thermomechanical analysis. As an answer to the industrial need, a new model is proposed and applied in cooling conditions encountered in L-PBF. It includes the initial solidification conditions and follows the phases, and their composition in the interdendritic liquid region to predict the brittle temperature range. Both dendrite tip growth model and kinetic phase diagram due to non-e...
HAL (Le Centre pour la Communication Scientifique Directe), Apr 10, 2019
HAL (Le Centre pour la Communication Scientifique Directe), Oct 15, 2019
HAL (Le Centre pour la Communication Scientifique Directe), Jun 20, 2022
HAL (Le Centre pour la Communication Scientifique Directe), Feb 26, 2017
Spark Plasma Sintering (SPS) is a process belonging to the powder metallurgy family. It consists ... more Spark Plasma Sintering (SPS) is a process belonging to the powder metallurgy family. It consists in applying simultaneously a load and a high intensity pulsed direct current on graphite tools containing powder to sinter this latter. The originality of this study lies on the in-situ SPS compression creep tests performed on TiAl 48-2-2 dense and porous samples, completed by SPS powder densification to established the creep law of this material. Once determined, it is then used in a fully-coupled simulation tool to predict temperature field and density gradient within the samples. The experimental relative density map will be presented and the correlation with the numerical model will be analyzed, both on simple and complex shape specimens. The evolution of the microstructure during creep test as well as after densification of a complex part will be presented and correlation with numerically assessed temperature field will be discussed.
A 3D finite element model is developed to study heat exchange during the selective laser melting ... more A 3D finite element model is developed to study heat exchange during the selective laser melting (SLM) process. The level set functions are used to track the interface between the constructed workpiece and non-melted powder, and interface between the gas domain and the successive powder bed layers In order to reach the simulation in macroscopic scale of real part geometries in a reasonable simulation time, the energy input and the formation of the additive deposit are simplified by considering them at the scale of an entire layer or fraction of each layer. The layer fractions are identified directly from a description (e.g. using G-code) of the global laser scan plan of the part construction. Each fraction is heated during a time interval corresponding to the exposure time to the laser beam, and then cooled down during a time interval equal to the scan time of the laser beam over the considered layer fraction. The global heat transfer through the part under additive construction and the powder material non-exposed to the laser beam is simulated. To reduce the computational cost, mesh-adaptation is adopted during the construction process. The proposed model is able to predict the temperature distribution and evolution in the constructed workpiece and non-melted powder during the SLM process at the macroscale, for parts made of complex geometry. Application is shown for a nickel based material (IN718), but the numerical model can be easily extended to other materials by using their data sets.
HAL (Le Centre pour la Communication Scientifique Directe), May 13, 2016
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Oct 5, 2021
HAL (Le Centre pour la Communication Scientifique Directe), May 30, 2018
HAL (Le Centre pour la Communication Scientifique Directe), Jun 17, 2019
Item Description: ASM International. Hardback. Book Condition: new. BRAND NEW, Modelling in Weldi... more Item Description: ASM International. Hardback. Book Condition: new. BRAND NEW, Modelling in Welding, Hot Powder Forming and Casting, Lennart Karlsson, This reference work provides thorough coverage of theoretical foundations of the thermomechanical modeling of welding, hot powder forming, and casting processes, which can also be applied to modeling of the heat treatment and forging of solids. Information on finite element modeling methods will assist design engineers in taking manufacturing processes into consideration to minimize residual stresses and deformation in the design of mechanical components. Contents: Thermomechanical Modeling Thermal Modeling of Welds Mechanical Modeling of Welding and Residual Stresses in Welds Metallurgical and Mechanical Consequences of Phase Transformations in Numerical Simulations of Welding Processes Predicting and Measuring Methods of Two- and Three-Dimensional Residual Stresses by Using Inherent Strain as a Parameter Hot Isostatic Pressing Hot Powder Forging And More. Bookseller Inventory # B9780871706164
HAL (Le Centre pour la Communication Scientifique Directe), Jun 27, 2016
International audienceThe standard riveting process used for joining stiffeners (AA 7075) to pane... more International audienceThe standard riveting process used for joining stiffeners (AA 7075) to panels (AA 2024) in aeronautic industry has a detrimental effect on the weight of planes. Friction stir welding (FSW) process is seen as an interesting option and a promising alternative process to lighten aircraft structure. However the mechanical properties in these grades are linked to structural hardening due to the solid state development of fine and densely distributed precipitates. FSW processes are known to affect these precipitates and the final properties of the welds. Thus the estimation of precipitate evolutions is of prime importance in order to deliver reliable welds to the aircraft industry. A time-efficient solid-state precipitation modelling based on a reliable thermodynamic description has been developed in order to predict the precipitate distribution and the related mechanical properties. At a micro scale, a particle size distribution approach (PSD) [1] is proposed for multi-components alloys to predict the nucleation, growth, dissolution and coarsening of both stable and metastable phases. The model is coupled to thermodynamic computations [2] in order to determine precipitate/matrix equilibrium compositions and associated growth velocity. This microstructural model is applied on a AA 2024 aluminium alloy in order to model both stable (S-phase) and metastable (GPB zones) phases. A DSC (Differential Scanning Calorimetry) calibration procedure has been developed to determine the nucleation parameters (Fig. 1 a). At a larger scale, a macro-structural model is used to define precisely the thermo-mechanical evolutions of the metal parts and thermal evolution inside welds [3]. Then, it is possible to couple the micro/macro models in order to define precisely the precipitate evolutions in nuggets, TMAZ and HAZ domains leading to heterogeneous mechanical properties (Fig. 1 b). The final mechanical properties are presented and discussed.[1] V. Legrand, Modélisation des processus de précipitation et prédiction des propriétés mécaniques résultantes dans les alliages d’aluminium à durcissement structural – Application au soudage par Friction Malaxage (FSW) de tôles AA2024, Doct. MinesParisTech, 2015[2]TCAL3, TCS Al-based alloys thermodynamic database, TC software AB (Stockholm, Sweden), 2014.[3]S. Gastebois, Simulation numérique 3D du FSW à l’aide d'une formulation ALE, Doct. Mines Paristech, 201
HAL (Le Centre pour la Communication Scientifique Directe), Jun 7, 2009
IOP conference series, 2023
In the present work, a methodology to identify parameters of an elastic viscoplastic behaviour la... more In the present work, a methodology to identify parameters of an elastic viscoplastic behaviour law is presented. Orthotropic elasticity and Hill48 plastic anisotropy for as-cast CMSX-4 are considered. In order to obtain the corresponding parameters by inverse analysis, an experimental database is built by tensile/relaxation tests at constant temperatures between 800°C and 1200°C on specimens oriented along <001>, <110> and <111> directions at different strain rates. Tests are performed with a resistive heating machine, using infrared thermography and digital image correlation. The obtained mechanical behaviour is very dependent on specimen orientation at all tested temperatures. Recrystallization behaviour is also very relevant to the specimens’ orientation.
HAL (Le Centre pour la Communication Scientifique Directe), May 11, 2022
HAL (Le Centre pour la Communication Scientifique Directe), Jun 20, 2022
HAL (Le Centre pour la Communication Scientifique Directe), Mar 14, 2006
HAL (Le Centre pour la Communication Scientifique Directe), Oct 25, 2017
The objective of this work is to develop new numerical simulation techniques in meso- and macro-s... more The objective of this work is to develop new numerical simulation techniques in meso- and macro-scale to optimize the LBM process. The two scale models are under a level-set framework. A meso-scale simulation focuses on the laser interaction with the powder bed and subsequent melting and solidification. Thermomechanical finite element (FE) modelling is conducted at the scale of material deposition, and addresses the melting of the powder bed, the hydrodynamics of the fusion zone and the formation of local thermal stresses in the wake of the laser. A macro-scale simulation focuses on part construction. This thermomechanical finite element model addresses heat exchange and stress formation at the scale of the part by considering the non-exposed powder. In order to reach reasonable simulation time for industrial parts, the energy input and the formation of the additive deposit are simplified by considering them at the scale of an entire layer or fractions of each layer.
HAL (Le Centre pour la Communication Scientifique Directe), May 17, 2017
A 3D finite element model is developed to study heat exchange during the selective laser melting ... more A 3D finite element model is developed to study heat exchange during the selective laser melting (SLM) process. The level set functions are used to track the interface between the constructed workpiece and non-melted powder, and interface between the gas domain and the successive powder bed layers In order to reach the simulation in macroscopic scale of real part geometries in a reasonable simulation time, the energy input and the formation of the additive deposit are simplified by considering them at the scale of an entire layer or fraction of each layer. The layer fractions are identified directly from a description (e.g. using G-code) of the global laser scan plan of the part construction. Each fraction is heated during a time interval corresponding to the exposure time to the laser beam, and then cooled down during a time interval equal to the scan time of the laser beam over the considered layer fraction. The global heat transfer through the part under additive construction and the powder material non-exposed to the laser beam is simulated. To reduce the computational cost, mesh-adaptation is adopted during the construction process. The proposed model is able to predict the temperature distribution and evolution in the constructed workpiece and non-melted powder during the SLM process at the macroscale, for parts made of complex geometry. Application is shown for a nickel based material (IN718), but the numerical model can be easily extended to other materials by using their data sets.
IOP Conference Series: Materials Science and Engineering
Laser Powder Bed Fusion (L-PBF) is seen as a process of interest by aeronautical industry to deve... more Laser Powder Bed Fusion (L-PBF) is seen as a process of interest by aeronautical industry to develop new engine components. Nevertheless, the reliability and durability of parts produced by L-PBF depend on the possibility to suppress the occurrence of defects. Among them, hot cracking represents a key issue. These cracks are due to the liquid film remaining between grains at the end of the solidification stage combined with stresses and strains endured by the mushy domain. A microsegregation model providing relevant prediction of the solidification path during L-PBF is thus required for coupling with a thermomechanical analysis. As an answer to the industrial need, a new model is proposed and applied in cooling conditions encountered in L-PBF. It includes the initial solidification conditions and follows the phases, and their composition in the interdendritic liquid region to predict the brittle temperature range. Both dendrite tip growth model and kinetic phase diagram due to non-e...
HAL (Le Centre pour la Communication Scientifique Directe), Apr 10, 2019
HAL (Le Centre pour la Communication Scientifique Directe), Oct 15, 2019
HAL (Le Centre pour la Communication Scientifique Directe), Jun 20, 2022