SAM
https://sam.ensam.eu:443
The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 20 Jun 2021 20:01:14 GMT2021-06-20T20:01:14ZIn-situ experimental and numerical studies of the damage evolution and fracture in a Fe-TiB2 composite
http://hdl.handle.net/10985/13283
In-situ experimental and numerical studies of the damage evolution and fracture in a Fe-TiB2 composite
HADJEM-HAMOUCHE, Z.; DERRIEN, Katell; HÉRIPRÉ, E.; CHEVALIER, Jean-Pierre
A joint experimental and modelling study of plastic strain and ensuing damage in a novel metal matrix composite (Fe-TiB2) is presented. Damage is observed and quantified using SEM images processing and Acoustic Emission (AE) analysis. The use of AE confirms that the surface damage observed is strongly correlated to damage in the bulk of the material. The primary mode of damage is particle fracture. Very little particle decohesion is observed, indicating an exceptionally good cohesion of the steel/particle interface. Damage is initiated soon after the composite yield point is reached and increases significantly with strain. Macroscopic failure of the tensile specimen occurs when about 25% of the particles are fractured. This corresponds to about 21% engineering strain. Using in-situ SEM tensile tests with quantitative digital image correlation (DIC), full-field strain measurements are obtained and particle fracture quantified. The results of fields measurements are compared to results of a FFT based homogenization method with boundary conditions retrieved from the experiment. A good agreement is found between the DIC-measured and FFT-predicted results. Estimated values of the particle fracture stress are obtained.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/132832018-01-01T00:00:00ZHADJEM-HAMOUCHE, Z.DERRIEN, KatellHÉRIPRÉ, E.CHEVALIER, Jean-PierreA joint experimental and modelling study of plastic strain and ensuing damage in a novel metal matrix composite (Fe-TiB2) is presented. Damage is observed and quantified using SEM images processing and Acoustic Emission (AE) analysis. The use of AE confirms that the surface damage observed is strongly correlated to damage in the bulk of the material. The primary mode of damage is particle fracture. Very little particle decohesion is observed, indicating an exceptionally good cohesion of the steel/particle interface. Damage is initiated soon after the composite yield point is reached and increases significantly with strain. Macroscopic failure of the tensile specimen occurs when about 25% of the particles are fractured. This corresponds to about 21% engineering strain. Using in-situ SEM tensile tests with quantitative digital image correlation (DIC), full-field strain measurements are obtained and particle fracture quantified. The results of fields measurements are compared to results of a FFT based homogenization method with boundary conditions retrieved from the experiment. A good agreement is found between the DIC-measured and FFT-predicted results. Estimated values of the particle fracture stress are obtained.The effect of moisture-induced swelling on the absorption capacity of transversely isotropic elastic polymer-matrix composites
http://hdl.handle.net/10985/6685
The effect of moisture-induced swelling on the absorption capacity of transversely isotropic elastic polymer-matrix composites
DERRIEN, Katell; GILORMINI, Pierre
The interaction between humid air and transversely isotropic fiber-reinforced composites with swelling polymeric matrix is considered. A model is proposed for the water saturation level in a polymer when stresses are applied, that uses directly obtainable material parameters only. In a composite, the reinforcements modify the water uptake of the polymer matrix because of the internal stresses that are induced by its restricted swelling, and this effect is evaluated. As a consequence of the coupling between stresses and absorption capacity, the sorption isotherm of a composite is ruled by the (nonlinear) Langmuir equation when the unreinforced matrix obeys the (linear) Henry’s law.
Thu, 01 Jan 2009 00:00:00 GMThttp://hdl.handle.net/10985/66852009-01-01T00:00:00ZDERRIEN, KatellGILORMINI, PierreThe interaction between humid air and transversely isotropic fiber-reinforced composites with swelling polymeric matrix is considered. A model is proposed for the water saturation level in a polymer when stresses are applied, that uses directly obtainable material parameters only. In a composite, the reinforcements modify the water uptake of the polymer matrix because of the internal stresses that are induced by its restricted swelling, and this effect is evaluated. As a consequence of the coupling between stresses and absorption capacity, the sorption isotherm of a composite is ruled by the (nonlinear) Langmuir equation when the unreinforced matrix obeys the (linear) Henry’s law.The effect of applied stresses on the equilibrium moisture content in polymers
http://hdl.handle.net/10985/6561
The effect of applied stresses on the equilibrium moisture content in polymers
DERRIEN, Katell; GILORMINI, Pierre
The relation between saturation moisture content in a polymer and applied stresses is derived as a function of the coefficient of moisture expansion. The model predictions are compared favourably with experimental data taken from the literature.
Mon, 01 Jan 2007 00:00:00 GMThttp://hdl.handle.net/10985/65612007-01-01T00:00:00ZDERRIEN, KatellGILORMINI, PierreThe relation between saturation moisture content in a polymer and applied stresses is derived as a function of the coefficient of moisture expansion. The model predictions are compared favourably with experimental data taken from the literature.A homogenization-based damage model for stiffness loss in ductile metal-matrix composites(Article)
http://hdl.handle.net/10985/18376
A homogenization-based damage model for stiffness loss in ductile metal-matrix composites(Article)
DORHMI, Khaoula; MORIN, LEO; DERRIEN, Katell; HADJEM-HAMOUCHE, Zehoua; CHEVALIER, Jean - Pierre
The aim of this paper is to develop a homogenized model that permits to describe the progressive loss of stiffness observed experimentally on ductile metal-matrix composites subjected to mechanical loadings. A two-step homogenization procedure is proposed to describe the effect of damage on the elastic properties. Since damage is solely driven by plastic deformation, a Gurson-type model is considered to describe the nucleation and growth of voids. Completed by appropriate evolution equations of the microstructure, this model of plasticity is used to update the elastic properties that are described by a mean-field homogenization scheme. The complete incremental model is implemented numerically and applied to the prediction of the stiffness loss. The model predictions are in very good agreement with experimental results on Al-SiC composites, cast irons and steel composites.
Wed, 01 Jan 2020 00:00:00 GMThttp://hdl.handle.net/10985/183762020-01-01T00:00:00ZDORHMI, KhaoulaMORIN, LEODERRIEN, KatellHADJEM-HAMOUCHE, ZehouaCHEVALIER, Jean - PierreThe aim of this paper is to develop a homogenized model that permits to describe the progressive loss of stiffness observed experimentally on ductile metal-matrix composites subjected to mechanical loadings. A two-step homogenization procedure is proposed to describe the effect of damage on the elastic properties. Since damage is solely driven by plastic deformation, a Gurson-type model is considered to describe the nucleation and growth of voids. Completed by appropriate evolution equations of the microstructure, this model of plasticity is used to update the elastic properties that are described by a mean-field homogenization scheme. The complete incremental model is implemented numerically and applied to the prediction of the stiffness loss. The model predictions are in very good agreement with experimental results on Al-SiC composites, cast irons and steel composites.Designing isotropic composites reinforced by aligned transversely isotropic particles of spheroidal shape
http://hdl.handle.net/10985/14495
Designing isotropic composites reinforced by aligned transversely isotropic particles of spheroidal shape
DERRIEN, Katell; MORIN, Léo; GILORMINI, Pierre
The aim of this paper is to study the design of isotropic composites reinforced by aligned spheroidal particles made of a transversely isotropic material. The problem is investigated analytically using the framework of mean- eld homogenization. Conditions of macroscopic isotropy of particle-reinforced composites are derived for the dilute and Mori-Tanaka's schemes. This leads to a system of three nonlinear equations linking seven material constants and two geometrical constants. A design tool is finally proposed which permits to determine admissible particles achieving macroscopic isotropy for a given isotropic matrix behavior and a given particle aspect ratio. Correlations between transverse and longitudinal moduli of admissible particles are stud- ied for various particle shapes. Finally, the design of particles is investigated for aluminum and steel matrix composites.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/144952018-01-01T00:00:00ZDERRIEN, KatellMORIN, LéoGILORMINI, PierreThe aim of this paper is to study the design of isotropic composites reinforced by aligned spheroidal particles made of a transversely isotropic material. The problem is investigated analytically using the framework of mean- eld homogenization. Conditions of macroscopic isotropy of particle-reinforced composites are derived for the dilute and Mori-Tanaka's schemes. This leads to a system of three nonlinear equations linking seven material constants and two geometrical constants. A design tool is finally proposed which permits to determine admissible particles achieving macroscopic isotropy for a given isotropic matrix behavior and a given particle aspect ratio. Correlations between transverse and longitudinal moduli of admissible particles are stud- ied for various particle shapes. Finally, the design of particles is investigated for aluminum and steel matrix composites.Generalized Euclidean Distances for Elasticity Tensors
http://hdl.handle.net/10985/18389
Generalized Euclidean Distances for Elasticity Tensors
MORIN, LEO; GILORMINI, Pierre; DERRIEN, Katell
The aim of this short paper is to provide, for elasticity tensors, generalized Euclidean distances that preserve the property of invariance by inversion. First, the elasticity law is expressed under a non-dimensional form by means of a gauge, which leads to an expression of elasticity (stiffness or compliance) tensors without units. Based on the difference between functions of the dimensionless tensors, generalized Euclidean distances are then introduced. A subclass of functions is proposed, which permits the retrieval of the classical log-Euclidean distance and the derivation of new distances, namely the arctan-Euclidean and power-Euclidean distances. Finally, these distances are applied to the determination of the closest isotropic tensor to a given elasticity tensor
Wed, 01 Jan 2020 00:00:00 GMThttp://hdl.handle.net/10985/183892020-01-01T00:00:00ZMORIN, LEOGILORMINI, PierreDERRIEN, KatellThe aim of this short paper is to provide, for elasticity tensors, generalized Euclidean distances that preserve the property of invariance by inversion. First, the elasticity law is expressed under a non-dimensional form by means of a gauge, which leads to an expression of elasticity (stiffness or compliance) tensors without units. Based on the difference between functions of the dimensionless tensors, generalized Euclidean distances are then introduced. A subclass of functions is proposed, which permits the retrieval of the classical log-Euclidean distance and the derivation of new distances, namely the arctan-Euclidean and power-Euclidean distances. Finally, these distances are applied to the determination of the closest isotropic tensor to a given elasticity tensorMultiscale modeling of the effective viscoplastic behavior of Mg 2 SiO 4 wadsleyite: bridging atomic and polycrystal scales
http://hdl.handle.net/10985/19938
Multiscale modeling of the effective viscoplastic behavior of Mg 2 SiO 4 wadsleyite: bridging atomic and polycrystal scales
CASTELNAU, Olivier; DERRIEN, Katell; RITTERBEX, S.; CARREZ, P.; CORDIER, P.; MOULINEC, H.
The viscoplastic behavior of polycrystalline Mg2SiO4 wadsleyite aggregates, a major high pressure phase of the mantle transition zone of the Earth (depth range: 410–520 km), is obtained by properly bridging several scale transition models. At the very fine nanometric scale corresponding to the dislocation core structure, the behavior of thermally activated plastic slip is modeled for strain-rates relevant for laboratory experimental conditions, at high pressure and for a wide range of temperatures, based on the Peierls–Nabarro–Galerkin model. Corresponding single slip reference resolved shear stresses and associated constitutive equations are deduced from Orowan’s equation in order to describe the average viscoplastic behavior at the grain scale, for the easiest slip systems. These data have been implemented in two grain-polycrystal scale transition models, a mean-field one (the recent Fully-Optimized Second-Order Viscoplastic Self-Consistent scheme of [1]) allowing rapid evaluation of the effective viscosity of polycrystalline aggregates, and a full-field (FFT based [2, 3]) method allowing investigating stress and strain-rate localization in typical microstructures and heterogeneous activation of slip systems within grains. Calculations have been performed at pressure and temperatures relevant for in-situ conditions. Results are in very good agreement with available mechanical tests conducted at strain-rates typical for laboratory experiments.
Wed, 01 Jan 2020 00:00:00 GMThttp://hdl.handle.net/10985/199382020-01-01T00:00:00ZCASTELNAU, OlivierDERRIEN, KatellRITTERBEX, S.CARREZ, P.CORDIER, P.MOULINEC, H.The viscoplastic behavior of polycrystalline Mg2SiO4 wadsleyite aggregates, a major high pressure phase of the mantle transition zone of the Earth (depth range: 410–520 km), is obtained by properly bridging several scale transition models. At the very fine nanometric scale corresponding to the dislocation core structure, the behavior of thermally activated plastic slip is modeled for strain-rates relevant for laboratory experimental conditions, at high pressure and for a wide range of temperatures, based on the Peierls–Nabarro–Galerkin model. Corresponding single slip reference resolved shear stresses and associated constitutive equations are deduced from Orowan’s equation in order to describe the average viscoplastic behavior at the grain scale, for the easiest slip systems. These data have been implemented in two grain-polycrystal scale transition models, a mean-field one (the recent Fully-Optimized Second-Order Viscoplastic Self-Consistent scheme of [1]) allowing rapid evaluation of the effective viscosity of polycrystalline aggregates, and a full-field (FFT based [2, 3]) method allowing investigating stress and strain-rate localization in typical microstructures and heterogeneous activation of slip systems within grains. Calculations have been performed at pressure and temperatures relevant for in-situ conditions. Results are in very good agreement with available mechanical tests conducted at strain-rates typical for laboratory experiments.Periodic smoothing splines for FFT-based solvers
http://hdl.handle.net/10985/19944
Periodic smoothing splines for FFT-based solvers
MORIN, Léo; BRENNER, Renald; DERRIEN, Katell; DORHMI, Khaoula
The aim of this paper is to develop a periodic smoother based on splines for FFT-based solvers. Spurious oscillations in FFT-based methods are shown to be due to pseudo-spectral differentiation of discontinuous fields. An automatic smoother based on polynomial splines is developed, which permits to add smoothness to initial material properties. The method, which is applied in various problems including conductivity, elasticity and field dislocation mechanics, improves significantly the local fields and reduces spurious oscillations.
Fri, 01 Jan 2021 00:00:00 GMThttp://hdl.handle.net/10985/199442021-01-01T00:00:00ZMORIN, LéoBRENNER, RenaldDERRIEN, KatellDORHMI, KhaoulaThe aim of this paper is to develop a periodic smoother based on splines for FFT-based solvers. Spurious oscillations in FFT-based methods are shown to be due to pseudo-spectral differentiation of discontinuous fields. An automatic smoother based on polynomial splines is developed, which permits to add smoothness to initial material properties. The method, which is applied in various problems including conductivity, elasticity and field dislocation mechanics, improves significantly the local fields and reduces spurious oscillations.