https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Mon, 13 Jul 2026 06:23:14 GMT 2026-07-13T06:23:14Z http://hdl.handle.net/10985/6677 Study on the temperature dependence of the bulk modulus of polyisoprene by molecular dynamics simulations DIANI, Julie; GILORMINI, Pierre; FAYOLLE, Bruno The temperature dependence of the bulk modulus of polyisoprene has been studied using molecular dynamics simulations. Virtual polyisoprenes have been submitted to volume contractions above and below the glass transition. Bulk modulus has been observed to be linearly dependent on temperature both above and below the glass transition respectively, and it dropped by a factor of about 2 while temperatures was risen above the glass transition. By monitoring the energy changes during volume contractions, it was observed that the bulk modulus arises mainly from the Van de Waals interactions. Nevertheless, the entropy contribution to the bulk modulus becomes significant above the glass transition. At a first order, the entropy part of the bulk modulus can be considered as independent on the temperature. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/10985/6677 2008-01-01T00:00:00Z DIANI, Julie GILORMINI, Pierre FAYOLLE, Bruno The temperature dependence of the bulk modulus of polyisoprene has been studied using molecular dynamics simulations. Virtual polyisoprenes have been submitted to volume contractions above and below the glass transition. Bulk modulus has been observed to be linearly dependent on temperature both above and below the glass transition respectively, and it dropped by a factor of about 2 while temperatures was risen above the glass transition. By monitoring the energy changes during volume contractions, it was observed that the bulk modulus arises mainly from the Van de Waals interactions. Nevertheless, the entropy contribution to the bulk modulus becomes significant above the glass transition. At a first order, the entropy part of the bulk modulus can be considered as independent on the temperature. http://hdl.handle.net/10985/9223 Direct experimental evidence of time-temperature superposition at finite strain for an amorphous polymer network DIANI, Julie; GILORMINI, Pierre; ARRIETA, Juan Sebastian The time-temperature superposition property of an amorphous polymer acrylate network is characterized at infinitesimal strain by standard dynamic mechanical analysis tests. Comparison of the shift factors determined in uniaxial tension and in torsion shows that both tests provide equivalent time-temperature superposition properties. More interestingly, finite strain uniaxial tension tests run until break at constant strain rate show that the acrylate network exhibits the same time-temperature superposition property at finite strain as at infinitesimal strain. Such original experimental evidence provides new insight for finite strain constitutive modelling of polymer amorphous networks. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9223 2015-01-01T00:00:00Z DIANI, Julie GILORMINI, Pierre ARRIETA, Juan Sebastian The time-temperature superposition property of an amorphous polymer acrylate network is characterized at infinitesimal strain by standard dynamic mechanical analysis tests. Comparison of the shift factors determined in uniaxial tension and in torsion shows that both tests provide equivalent time-temperature superposition properties. More interestingly, finite strain uniaxial tension tests run until break at constant strain rate show that the acrylate network exhibits the same time-temperature superposition property at finite strain as at infinitesimal strain. Such original experimental evidence provides new insight for finite strain constitutive modelling of polymer amorphous networks. http://hdl.handle.net/10985/9629 A numerical study of the influence of polydispersity on the behaviour until break of a reinforced hyperelastic material with a cohesive interface TOULEMONDE, Paul-Aymé; DIANI, Julie; GILORMINI, Pierre; DESGARDIN, Nancy Solid propellants manufacturers commonly monitor the granulometries of the explosive fllers they introduce in the material to pack high fller volume fraction and thus obtain satisfactory energetic performance. However, to our knowledge, the effect of a mix of small and large particles in the micrometric size range in flled elastomers has not yet been fully understood. This work aims at producing a better understanding of the underlying mechanisms that take place in a bidisperse flled elastomer composite under uniaxial loading by using finite element simulations. An original process for creating bidisperse microstructures is proposed and analyzed. The key role of the fller/matrix interface is emphasized through the use of a cohesive zone model. Plane- strain simulations in uniaxial tension of such cells with different fractions of large and small particles are performed. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9629 2015-01-01T00:00:00Z TOULEMONDE, Paul-Aymé DIANI, Julie GILORMINI, Pierre DESGARDIN, Nancy Solid propellants manufacturers commonly monitor the granulometries of the explosive fllers they introduce in the material to pack high fller volume fraction and thus obtain satisfactory energetic performance. However, to our knowledge, the effect of a mix of small and large particles in the micrometric size range in flled elastomers has not yet been fully understood. This work aims at producing a better understanding of the underlying mechanisms that take place in a bidisperse flled elastomer composite under uniaxial loading by using finite element simulations. An original process for creating bidisperse microstructures is proposed and analyzed. The key role of the fller/matrix interface is emphasized through the use of a cohesive zone model. Plane- strain simulations in uniaxial tension of such cells with different fractions of large and small particles are performed. http://hdl.handle.net/10985/8457 Physical interpretation of the Mullins softening in a carbon-black filled SBR DIAZ, Rodrigo; DIANI, Julie; GILORMINI, Pierre A 40 phr carbon-black filled styrene butadiene rubber has been submitted to several experiments in order to identify the physical damage responsible for the mechanical softening recorded upon first stretch. Damage in the rubber matrix was determined by swelling. The filler structure alteration was monitored by electrical conductivity measurements. Both damages are shown to be of minor importance compared to the substantial mechanical softening undergone by the material. Degradation at the rubber-filler interface may be recovered by exposing the material at high temperatures in vacuo. The chain mobility in such storage conditions promotes free chain adsorption at the filler surface. The existence of a layer of polymer whose movements are hindered adds to the filler reinforcement and its desorption creates Mullins softening. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8457 2014-01-01T00:00:00Z DIAZ, Rodrigo DIANI, Julie GILORMINI, Pierre A 40 phr carbon-black filled styrene butadiene rubber has been submitted to several experiments in order to identify the physical damage responsible for the mechanical softening recorded upon first stretch. Damage in the rubber matrix was determined by swelling. The filler structure alteration was monitored by electrical conductivity measurements. Both damages are shown to be of minor importance compared to the substantial mechanical softening undergone by the material. Degradation at the rubber-filler interface may be recovered by exposing the material at high temperatures in vacuo. The chain mobility in such storage conditions promotes free chain adsorption at the filler surface. The existence of a layer of polymer whose movements are hindered adds to the filler reinforcement and its desorption creates Mullins softening. http://hdl.handle.net/10985/8156 Constitutive modeling of the anisotropic behavior of Mullins softened filled rubbers MERCKEL, Yannick; DIANI, Julie; BRIEU, Mathias; CAILLARD, Julien Original constitutive modeling is proposed for filled rubber materials in order to capture the anisotropic softened behavior induced by general non-proportional pre-loading histo-ries. The hyperelastic framework is grounded on a thorough analysis of cyclic experimental data. The strain energy density is based on a directional approach. The model leans on the strain amplification factor concept applied over material directions according to the Mul-lins softening evolution. In order to provide a model versatile that applies for a wide range of materials, the proposed framework does not require to postulate the mathematical forms of the elementary directional strain energy density and of the Mullins softening evo-lution rule. A computational procedure is defined to build both functions incrementally from experimental data obtained during cyclic uniaxial tensile tests. Successful compari-sons between the model and the experiments demonstrate the model abilities. Moreover, the model is shown to accurately predict the non-proportional uniaxial stress-stretch responses for uniaxially and biaxially pre-stretched samples. Finally, the model is effi-ciently tested on several materials and proves to provide a quantitative estimate of the anisotropy induced by the Mullins softening for a wide range of filled rubbers. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10985/8156 2012-01-01T00:00:00Z MERCKEL, Yannick DIANI, Julie BRIEU, Mathias CAILLARD, Julien Original constitutive modeling is proposed for filled rubber materials in order to capture the anisotropic softened behavior induced by general non-proportional pre-loading histo-ries. The hyperelastic framework is grounded on a thorough analysis of cyclic experimental data. The strain energy density is based on a directional approach. The model leans on the strain amplification factor concept applied over material directions according to the Mul-lins softening evolution. In order to provide a model versatile that applies for a wide range of materials, the proposed framework does not require to postulate the mathematical forms of the elementary directional strain energy density and of the Mullins softening evo-lution rule. A computational procedure is defined to build both functions incrementally from experimental data obtained during cyclic uniaxial tensile tests. Successful compari-sons between the model and the experiments demonstrate the model abilities. Moreover, the model is shown to accurately predict the non-proportional uniaxial stress-stretch responses for uniaxially and biaxially pre-stretched samples. Finally, the model is effi-ciently tested on several materials and proves to provide a quantitative estimate of the anisotropy induced by the Mullins softening for a wide range of filled rubbers. http://hdl.handle.net/10985/7357 Experimental characterization and thermoviscoelastic modeling of strain and stress recoveries of an amorphous polymer network ARRIETA, Juan Sebastian; DIANI, Julie; GILORMINI, Pierre An acrylate polymer network was submitted to thermomechanical shape memory cycles. The set of experiments characterized the material stress-free strain recovery and the strain-constrained stress recovery in uniaxial tension. Experimental parameters like temperature of strain fixation, amount of strain and heating rate, were varied in order to provide a relatively complete set of experimental data. A model combining the amorphous polymer viscoelasticity and its time–temperature superposition property was used to predict the shape memory behavior of the acrylate polymer network. All the model parameters were characterized using classical tests for mechanical characterization of polymers, which do not include shape memory tests. Model predictions obtained by finite element simulations compared very well to the experimental data and therefore the model relevance for computer assisted application design was assessed. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/7357 2014-01-01T00:00:00Z ARRIETA, Juan Sebastian DIANI, Julie GILORMINI, Pierre An acrylate polymer network was submitted to thermomechanical shape memory cycles. The set of experiments characterized the material stress-free strain recovery and the strain-constrained stress recovery in uniaxial tension. Experimental parameters like temperature of strain fixation, amount of strain and heating rate, were varied in order to provide a relatively complete set of experimental data. A model combining the amorphous polymer viscoelasticity and its time–temperature superposition property was used to predict the shape memory behavior of the acrylate polymer network. All the model parameters were characterized using classical tests for mechanical characterization of polymers, which do not include shape memory tests. Model predictions obtained by finite element simulations compared very well to the experimental data and therefore the model relevance for computer assisted application design was assessed. http://hdl.handle.net/10985/12466 On necessary precautions when measuring solid polymer linear viscoelasticity with dynamic analysis in torsion DIANI, Julie; GILORMINI, Pierre Solid polymer linear viscoelasticity in shear is often characterized by applying torsion and using the Saint-Venant solution when rectangular prismatic specimens are considered. It is shown that experimental dynamic torsion tests can show a dependency of the storage modulus and damping factor on the dimensions of the rectangular prismatic specimen when linear temperature ramps are applied. While the discrepancy of damping factor is explained by temperature heterogeneities and can be corrected easily by applying temperature steps, the inconsistency of storage modulus is due to an invalid application of the Saint-Venant solution. Finite element simulations allowed definition of the sample dimensions for which the Saint-Venant solution provides a good approximation, and a coefficient is given to correct the results obtained with commercial rheometers when other sample dimensions are used. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/12466 2017-01-01T00:00:00Z DIANI, Julie GILORMINI, Pierre Solid polymer linear viscoelasticity in shear is often characterized by applying torsion and using the Saint-Venant solution when rectangular prismatic specimens are considered. It is shown that experimental dynamic torsion tests can show a dependency of the storage modulus and damping factor on the dimensions of the rectangular prismatic specimen when linear temperature ramps are applied. While the discrepancy of damping factor is explained by temperature heterogeneities and can be corrected easily by applying temperature steps, the inconsistency of storage modulus is due to an invalid application of the Saint-Venant solution. Finite element simulations allowed definition of the sample dimensions for which the Saint-Venant solution provides a good approximation, and a coefficient is given to correct the results obtained with commercial rheometers when other sample dimensions are used. http://hdl.handle.net/10985/14496 Representative volume elements for the simulation of isotropic composites highly lled with monosized spheres FOUCAULT DE FRANCQUEVILLE; GILORMINI, Pierre; DIANI, Julie A method is proposed for generating reliable representative volume elements (RVEs) that allows reducing the statistical analysis required for the simulation of the mechanical behavior of isotropic composites highly filled with monosized spheres. The method combines (i) an algorithm inspired from molecular dynamics and associated with an analytical equation of state, and (ii) a geometrical analysis using the two-point correlation function and a nearest-neighbor distribution function. A restrictive selection process is defined, which leads to microstructures reasonably close to randomness and isotropy. The pertinence of the proposed generation and selection of RVEs is confirmed by the simulation of their elastic behavior with the nite element method. In particular, it is shown how the selection procedure allows reducing the computational e ort required to reach reliable elastic moduli by operating on a limited number of suitable RVEs. The results are in good agreement with the generalized self-consistent model and with original experimental data obtained on a composite where an acrylate matrix was reinforced by sifted glass beads. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/14496 2019-01-01T00:00:00Z FOUCAULT DE FRANCQUEVILLE GILORMINI, Pierre DIANI, Julie A method is proposed for generating reliable representative volume elements (RVEs) that allows reducing the statistical analysis required for the simulation of the mechanical behavior of isotropic composites highly filled with monosized spheres. The method combines (i) an algorithm inspired from molecular dynamics and associated with an analytical equation of state, and (ii) a geometrical analysis using the two-point correlation function and a nearest-neighbor distribution function. A restrictive selection process is defined, which leads to microstructures reasonably close to randomness and isotropy. The pertinence of the proposed generation and selection of RVEs is confirmed by the simulation of their elastic behavior with the nite element method. In particular, it is shown how the selection procedure allows reducing the computational e ort required to reach reliable elastic moduli by operating on a limited number of suitable RVEs. The results are in good agreement with the generalized self-consistent model and with original experimental data obtained on a composite where an acrylate matrix was reinforced by sifted glass beads. http://hdl.handle.net/10985/18437 Relationship between local damage and macroscopic response of soft materials highly reinforced by monodispersed particles DE FRANCQUEVILLE, Foucault; GILORMINI, Pierre; DIANI, Julie; VANDENBROUCKE, Aude A rubberlike matrix highly filled with spherical micrometric glass beads is submitted to uniaxial tension tests until break. X-ray tomography imaging performed on the material while submitted to uniaxial tension reveals early debonding at the matrix/filler interfaces at the poles of the particles followed by void coalescence creating damage localization. The latter causes a downturn of the macroscopic stress-strain response. These phenomena are analyzed further with three-dimensional finite element simulations, where 64 spherical beads are distributed randomly in a periodic cell. A simple version of the Tvergaard-Hutchinson cohesive-zone model allows to reproduce all the experimental trends well. The effects of the three parameters involved are analyzed, and three different types of macroscopic behaviors are observed corresponding to three different microstructure damages. The value of the initial stiffness of the interface, limited by numerical convergence, has little effect on how the local damage evolves but has a significant impact on the overall macroscopic stress values. The local damage is strongly dependent on the critical strength and the separation failure displacement, and the adhesion energy may be considered as a resulting parameter of the two previous ones. The interfacial critical strength appears to have a significant impact on the damage initiation, either spread across the structure for low values, or localized for high values. Increasing the interface separation failure displacement delays the possible loss of adhesion to a higher strain and preserves the integrity of the composite material. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18437 2020-01-01T00:00:00Z DE FRANCQUEVILLE, Foucault GILORMINI, Pierre DIANI, Julie VANDENBROUCKE, Aude A rubberlike matrix highly filled with spherical micrometric glass beads is submitted to uniaxial tension tests until break. X-ray tomography imaging performed on the material while submitted to uniaxial tension reveals early debonding at the matrix/filler interfaces at the poles of the particles followed by void coalescence creating damage localization. The latter causes a downturn of the macroscopic stress-strain response. These phenomena are analyzed further with three-dimensional finite element simulations, where 64 spherical beads are distributed randomly in a periodic cell. A simple version of the Tvergaard-Hutchinson cohesive-zone model allows to reproduce all the experimental trends well. The effects of the three parameters involved are analyzed, and three different types of macroscopic behaviors are observed corresponding to three different microstructure damages. The value of the initial stiffness of the interface, limited by numerical convergence, has little effect on how the local damage evolves but has a significant impact on the overall macroscopic stress values. The local damage is strongly dependent on the critical strength and the separation failure displacement, and the adhesion energy may be considered as a resulting parameter of the two previous ones. The interfacial critical strength appears to have a significant impact on the damage initiation, either spread across the structure for low values, or localized for high values. Increasing the interface separation failure displacement delays the possible loss of adhesion to a higher strain and preserves the integrity of the composite material. http://hdl.handle.net/10985/17958 Response of a carbon-black filled SBR under large strain cyclic uniaxial tension BRIEU, Mathias; DIANI, Julie; MIGNOT, Christian; MORICEAU, Christophe A carbon-black filled SBR was submitted to various uniaxial tension cyclic tests in order to study its cyclic softening. Stress-softening and stretch creep were monitored during stretch-control tests and ratcheting tests, respectively. The material softening induced by cyclic loadings appeared to depend on the maximum loading applied. The cyclic amplitude or equivalently the cyclic energy did not affect the material softening. The latter experimental result draws our attention since it contrasts with former results of the literature obtained on natural rubbers and butyl rubbers. Fri, 01 Jan 2010 00:00:00 GMT http://hdl.handle.net/10985/17958 2010-01-01T00:00:00Z BRIEU, Mathias DIANI, Julie MIGNOT, Christian MORICEAU, Christophe A carbon-black filled SBR was submitted to various uniaxial tension cyclic tests in order to study its cyclic softening. Stress-softening and stretch creep were monitored during stretch-control tests and ratcheting tests, respectively. The material softening induced by cyclic loadings appeared to depend on the maximum loading applied. The cyclic amplitude or equivalently the cyclic energy did not affect the material softening. The latter experimental result draws our attention since it contrasts with former results of the literature obtained on natural rubbers and butyl rubbers.