Michel Gratton - Academia.edu (original) (raw)

Papers by Michel Gratton

A novel modeling approach for describing the multiscale properties of ex vivo skin is proposed. A... more A novel modeling approach for describing the multiscale properties of ex vivo skin is proposed. An acousto-mechanical experiment using the mixing of a mechanical loading (conducted at 10 Hz frequency) and an ultrasonic 100 MHz TR-NEWS probing system has been implemented in order to extract the nonclassical nonlinearity of porcine skin. A 100 kN load cell, was used to measure displacement and tensile load. Various displacement rates were imposed (1 ; 0.5 and 0.1 mm/s) and the maximum elongation was set to 25 mm. To overcome the difficulty of skin aging characterization, the use of Preisach modeling (PM space) is suggested and confirmed. Since collagen fibrils exhibit a highly nonlinear mechanical response, the three main stress-strain regimes should be described pragmatically with a statistical approach provided by the Preisach model, which can be expressed as a weighted combination of relay operators (or hysterons). Hysteresis behavior coming from the complex loading of the skin is ...

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

Journal of Pressure Vessel Technology

Self-loosening of bolted joints is a common issue in structural connections and machine design. T... more Self-loosening of bolted joints is a common issue in structural connections and machine design. This phenomenon can not only cause the industry a lot of losses due to maintenance but can result in catastrophic incidents leading to environment and health issues. This paper presents a new analytical model with an improved criterion that could be used to predict self-loosening of bolted joints. A complete study involving analytical, numerical, and experimental work has been conducted to give an insight of the mechanism leading to self-loosening of bolted joints and support the developed model. Particular focus is put on the effect of the clamping plate thickness on the self-loosening of the joint. A fully instrumented experimental setup, in conjunction with an M12-1.75 bolt, is deployed to track the bolt tension decrease with the application of an imposed cyclic transverse displacement. In addition to the measurement of the transverse relative displacement between the two clamping part...

Resources, Conservation and Recycling

Waste Management, 2016

This study focused on the possibility of recycling Waste Tire Rubber (WTR) to be used as polymer ... more This study focused on the possibility of recycling Waste Tire Rubber (WTR) to be used as polymer modifier. Thus, WTR was grinded into powder, at ambient temperature, with a disc mill PQ500 and microwave electromagnetic energy was used to devulcanize this powder with the final aim of producing a new composite by its incorporation in a thermoset resin. The influence of the treatment microwave energy on the devulcanization ratio was investigated. FTIR analysis revealed that rupture of Sulfur-Sulfur (SS) and Carbon-Sulfur (CS) bonds have occurred during the treatment. Swelling analysis showed that the microwave treatment can lead to a very significant degree of devulcanization. The Ground Tire Rubber (GTR) and the Devulcanized Ground Tire Rubber (DGTR) were then separately used to prepare epoxy based composites. It appeared that epoxy composites filled with DGTR have better mechanical properties than those filled with untreated GTR. This result agrees with scanning electron microscopy observations which highlighted a better interface coherence between DGTR and epoxy. A complementary analysis pointed out a linear relationship between the rubber modulus and the number of crosslink per chain.

Revue Européenne des Éléments Finis, 1998

Revue européenne des éléments finis

A method for the fracture prediction under dynamic loading of small structures made of a three-di... more A method for the fracture prediction under dynamic loading of small structures made of a three-dimensional carbon/carbon (C/C) composite is proposed. Due to the length scale of the loading, the notion of homogenized material is meaningless; our choice is to model, identify and compute the material at an intermediate scale or meso-scale. Our idea is that, due to the smallness of the meso-scale, the previous description of the damage mechanisms should be valid even for high-rate loading. The meso-modelling is based on the static and dynamic tests. Changing scale methods are applied to identify the mesoscopic model parameters (dommage-plasticity-porous) from static tests. The results of dynamic computing of plate/plate tests confirm the method.

Journal of Applied Physics, 1998

[Journal of Applied Physics 83, 5741 (1998)]. Stephane Bonnan, Pierre-Louis Hereil, Francis Collo... more [Journal of Applied Physics 83, 5741 (1998)]. Stephane Bonnan, Pierre-Louis Hereil, Francis Collombet. Abstract. ... These effects were also demonstrated on 22% porous 2024 aluminum by Butcher, Carroll, and Holt and Schock, Abey, and Duba as shown in Fig. ...

Le Journal de Physique IV, 1997

The compressive response of a 3D carbon-carbon composite under shock wave was studied in a platei... more The compressive response of a 3D carbon-carbon composite under shock wave was studied in a plateimpact configuration. Two directions of in~pact were achieved until a nominal value of longitudinal stress of 2.5 GPa. The measured wave profiles are consistent with previous results on 3D composites and confirm the behavim of such materials under impact. It is shown that the initial loading is decomposed in two waves. The first one is transmitted by the longil~rdinal fibres, the second one correspouds to the propagation of a shock wave in the 'matrix'. Macroscopic characteristics of this nlaterial arc provided. RCsumC. On presente la reporise sous choc d'un conlposite 3DCC i partir d'essai d'impact de plaques. Deux directions d'anisotropie ont tte etudiis jusqu'h une contrainte maximum de 2.5 GPa. La rorrne des diagrammes de vitesse est coherente avec les resultats deja obtenus sur les conlposites 3D et confirme leur co~nportement sous choc. On montre que la sollicitatio~~ initiale se decompose en deus ondes. La prernitre est transport& par les fibres longitudinales, la seconde par la matrice. On presente des caracteristiques macroscopiques calculks sur ce composite 3DCC.

Le Journal de Physique IV, 1997

A method for the fracture prediction under dynamic loading of small structures made of a 3D Carbo... more A method for the fracture prediction under dynamic loading of small structures made of a 3D CarbonICarbon composite is proposed. Due to the length scale of the loading, the notion of a homogenized material is meaningless; our choicc herein is to model, identify and compute the material at an intermediate or meso scale (fibre strandsmatrix blocks). Our idea is that, due to the smallness of the meso scale, the previous description of the damage mechanisms should be valid even for high-rate loading. This meso-modelling is based on static and dynamic tests. Changing scale methods are applied to identify the mesoscopic model parameters (damageplasticity porosity) from static tests. The results from the dynamic computing of platelplate tests confirm this method. Rbsum6: Une mithodologie pour la prtvision de la rupture sous choc, de pikces de petites dimensions en mattriaux 3D CIC, cst proposte. Pour ce type de sollicitations, la notion de matiriau homogkne equivalent est inadaptke. Aussi nous avons choisi de modCliser et d'identifier le mattriau I'ichelle de ses mtso-constituants: torons et blocs de matrice. Les calculs sont egalernent effectuCs B cette echelle. Le mtso-modkle diveloppi se nourrit d'infomations qualitatives obtenues par des essais statiques et dynamiques mais est identifie en statique. Un outil de changement d'dchelle est utilist, de f a p n iterative, pour identifier les paramktres du meso-modkle (torons-blocs de matrice). Des premikres simulations dynamiques d'essais d'impact plaquelplaque montrent I'intCrEt de la demarche.

Composites Science and Technology, 2001

A method for the prediction of fracture under dynamic loading for small structures made of a 3D c... more A method for the prediction of fracture under dynamic loading for small structures made of a 3D carbon/carbon composite is proposed. Owing to the length scale of the loading, the notion of homogenised material is meaningless and our choice then is to model, identify and compute the material at an intermediate or mesoscale (fibre-strands/matrix-blocks). The idea here is that, because

High Performance Structures and Materials III, 2006

ABSTRACT This paper deals with the characterization of the static mechanical behaviour of an ener... more ABSTRACT This paper deals with the characterization of the static mechanical behaviour of an energetic material. Due to the constituents (crystals and a polymeric binder), the behaviour is influenced by the pressure, the temperature and the strain rate. The temperature, considered varying slowly, is a parameter and the computational problems are uncoupled. Therefore, a complete experimental protocol and a model have been developed. Inspired from the Visco-Scram model, the behaviour is described using a general Maxwell model in which all the branches are affected by an isotropic damage. The first branch takes into account elastic-plastic behaviour. The yield stress is given by a parabolic criterion, characterized using compressive, tensile and tri-axial tests. The hardening is isotropic and the plastic flow rule is nonassociated. The other branches are viscoelastic. A genetic algorithm is used to optimise the viscoelastic parameters, previously obtained using DMA measurements. Comparisons between the model and experiments are proposed for different temperatures, strain rates and pressures. At last, a user material subroutine has been developed in Abaqus Standard and finite element computations of the Brazilian test are compared to the experimental response. Keywords: energetic material, parabolic plastic criterion, genetic algorithm, DMA, viscoelasticity, Isotropic damage, Brazilian tests.

Lecture Notes in Mechanical Engineering, 2013

ABSTRACT The opening-closing effect of the microcracks is a kinematic phenomenon usually modeled ... more ABSTRACT The opening-closing effect of the microcracks is a kinematic phenomenon usually modeled using a set of damage variables. The influence of microcracks must be taken into account depending on their opening or closing state, which results in different elasticity for the same level of damage. In this work, the volumetric, deviatoric and tangential model denoted as V-D-T is chosen and modified by introducing the opening-closing effect into the free energy. This model is coupled with a sliding-friction mechanism of the microcrack lips when the latter are closed. Simulations of compression tests with confinements are presented to validate the model.

Engineering Fracture Mechanics, 2014

ABSTRACT Modelling the behaviour of quasi-brittle materials requires dealing with the anisotropic... more ABSTRACT Modelling the behaviour of quasi-brittle materials requires dealing with the anisotropic damage evolution induced by the loading direction and the unilateral effect corresponding to the sudden opening/closure of defects. The latter was the cause deficiencies of some constitutive laws as a no continuous stress/strain response or spurious energy dissipation. In this paper, the behaviour of pressed high explosive is experimentally investigated. Evidences of a pre-existing damage, an anisotropic one developing during loading and the unilateral effect are detailed. The framework of the microplane constitutive laws previously proposed in the literature and based on the volumetric-deviatoric-tangential strain projections is used. Damage is introduced in the model and is affected by an "effectiveness" function weighting its influence with the loading direction. The calibration procedure is detailed and a discussion enables highlighting the strengths and weaknesses of the modelling approach.

A novel modeling approach for describing the multiscale properties of ex vivo skin is proposed. A... more A novel modeling approach for describing the multiscale properties of ex vivo skin is proposed. An acousto-mechanical experiment using the mixing of a mechanical loading (conducted at 10 Hz frequency) and an ultrasonic 100 MHz TR-NEWS probing system has been implemented in order to extract the nonclassical nonlinearity of porcine skin. A 100 kN load cell, was used to measure displacement and tensile load. Various displacement rates were imposed (1 ; 0.5 and 0.1 mm/s) and the maximum elongation was set to 25 mm. To overcome the difficulty of skin aging characterization, the use of Preisach modeling (PM space) is suggested and confirmed. Since collagen fibrils exhibit a highly nonlinear mechanical response, the three main stress-strain regimes should be described pragmatically with a statistical approach provided by the Preisach model, which can be expressed as a weighted combination of relay operators (or hysterons). Hysteresis behavior coming from the complex loading of the skin is ...

IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

Journal of Pressure Vessel Technology

Self-loosening of bolted joints is a common issue in structural connections and machine design. T... more Self-loosening of bolted joints is a common issue in structural connections and machine design. This phenomenon can not only cause the industry a lot of losses due to maintenance but can result in catastrophic incidents leading to environment and health issues. This paper presents a new analytical model with an improved criterion that could be used to predict self-loosening of bolted joints. A complete study involving analytical, numerical, and experimental work has been conducted to give an insight of the mechanism leading to self-loosening of bolted joints and support the developed model. Particular focus is put on the effect of the clamping plate thickness on the self-loosening of the joint. A fully instrumented experimental setup, in conjunction with an M12-1.75 bolt, is deployed to track the bolt tension decrease with the application of an imposed cyclic transverse displacement. In addition to the measurement of the transverse relative displacement between the two clamping part...

Resources, Conservation and Recycling

Waste Management, 2016

This study focused on the possibility of recycling Waste Tire Rubber (WTR) to be used as polymer ... more This study focused on the possibility of recycling Waste Tire Rubber (WTR) to be used as polymer modifier. Thus, WTR was grinded into powder, at ambient temperature, with a disc mill PQ500 and microwave electromagnetic energy was used to devulcanize this powder with the final aim of producing a new composite by its incorporation in a thermoset resin. The influence of the treatment microwave energy on the devulcanization ratio was investigated. FTIR analysis revealed that rupture of Sulfur-Sulfur (SS) and Carbon-Sulfur (CS) bonds have occurred during the treatment. Swelling analysis showed that the microwave treatment can lead to a very significant degree of devulcanization. The Ground Tire Rubber (GTR) and the Devulcanized Ground Tire Rubber (DGTR) were then separately used to prepare epoxy based composites. It appeared that epoxy composites filled with DGTR have better mechanical properties than those filled with untreated GTR. This result agrees with scanning electron microscopy observations which highlighted a better interface coherence between DGTR and epoxy. A complementary analysis pointed out a linear relationship between the rubber modulus and the number of crosslink per chain.

Revue Européenne des Éléments Finis, 1998

Revue européenne des éléments finis

A method for the fracture prediction under dynamic loading of small structures made of a three-di... more A method for the fracture prediction under dynamic loading of small structures made of a three-dimensional carbon/carbon (C/C) composite is proposed. Due to the length scale of the loading, the notion of homogenized material is meaningless; our choice is to model, identify and compute the material at an intermediate scale or meso-scale. Our idea is that, due to the smallness of the meso-scale, the previous description of the damage mechanisms should be valid even for high-rate loading. The meso-modelling is based on the static and dynamic tests. Changing scale methods are applied to identify the mesoscopic model parameters (dommage-plasticity-porous) from static tests. The results of dynamic computing of plate/plate tests confirm the method.

Journal of Applied Physics, 1998

[Journal of Applied Physics 83, 5741 (1998)]. Stephane Bonnan, Pierre-Louis Hereil, Francis Collo... more [Journal of Applied Physics 83, 5741 (1998)]. Stephane Bonnan, Pierre-Louis Hereil, Francis Collombet. Abstract. ... These effects were also demonstrated on 22% porous 2024 aluminum by Butcher, Carroll, and Holt and Schock, Abey, and Duba as shown in Fig. ...

Le Journal de Physique IV, 1997

The compressive response of a 3D carbon-carbon composite under shock wave was studied in a platei... more The compressive response of a 3D carbon-carbon composite under shock wave was studied in a plateimpact configuration. Two directions of in~pact were achieved until a nominal value of longitudinal stress of 2.5 GPa. The measured wave profiles are consistent with previous results on 3D composites and confirm the behavim of such materials under impact. It is shown that the initial loading is decomposed in two waves. The first one is transmitted by the longil~rdinal fibres, the second one correspouds to the propagation of a shock wave in the 'matrix'. Macroscopic characteristics of this nlaterial arc provided. RCsumC. On presente la reporise sous choc d'un conlposite 3DCC i partir d'essai d'impact de plaques. Deux directions d'anisotropie ont tte etudiis jusqu'h une contrainte maximum de 2.5 GPa. La rorrne des diagrammes de vitesse est coherente avec les resultats deja obtenus sur les conlposites 3D et confirme leur co~nportement sous choc. On montre que la sollicitatio~~ initiale se decompose en deus ondes. La prernitre est transport& par les fibres longitudinales, la seconde par la matrice. On presente des caracteristiques macroscopiques calculks sur ce composite 3DCC.

Le Journal de Physique IV, 1997

A method for the fracture prediction under dynamic loading of small structures made of a 3D Carbo... more A method for the fracture prediction under dynamic loading of small structures made of a 3D CarbonICarbon composite is proposed. Due to the length scale of the loading, the notion of a homogenized material is meaningless; our choicc herein is to model, identify and compute the material at an intermediate or meso scale (fibre strandsmatrix blocks). Our idea is that, due to the smallness of the meso scale, the previous description of the damage mechanisms should be valid even for high-rate loading. This meso-modelling is based on static and dynamic tests. Changing scale methods are applied to identify the mesoscopic model parameters (damageplasticity porosity) from static tests. The results from the dynamic computing of platelplate tests confirm this method. Rbsum6: Une mithodologie pour la prtvision de la rupture sous choc, de pikces de petites dimensions en mattriaux 3D CIC, cst proposte. Pour ce type de sollicitations, la notion de matiriau homogkne equivalent est inadaptke. Aussi nous avons choisi de modCliser et d'identifier le mattriau I'ichelle de ses mtso-constituants: torons et blocs de matrice. Les calculs sont egalernent effectuCs B cette echelle. Le mtso-modkle diveloppi se nourrit d'infomations qualitatives obtenues par des essais statiques et dynamiques mais est identifie en statique. Un outil de changement d'dchelle est utilist, de f a p n iterative, pour identifier les paramktres du meso-modkle (torons-blocs de matrice). Des premikres simulations dynamiques d'essais d'impact plaquelplaque montrent I'intCrEt de la demarche.

Composites Science and Technology, 2001

A method for the prediction of fracture under dynamic loading for small structures made of a 3D c... more A method for the prediction of fracture under dynamic loading for small structures made of a 3D carbon/carbon composite is proposed. Owing to the length scale of the loading, the notion of homogenised material is meaningless and our choice then is to model, identify and compute the material at an intermediate or mesoscale (fibre-strands/matrix-blocks). The idea here is that, because

High Performance Structures and Materials III, 2006

ABSTRACT This paper deals with the characterization of the static mechanical behaviour of an ener... more ABSTRACT This paper deals with the characterization of the static mechanical behaviour of an energetic material. Due to the constituents (crystals and a polymeric binder), the behaviour is influenced by the pressure, the temperature and the strain rate. The temperature, considered varying slowly, is a parameter and the computational problems are uncoupled. Therefore, a complete experimental protocol and a model have been developed. Inspired from the Visco-Scram model, the behaviour is described using a general Maxwell model in which all the branches are affected by an isotropic damage. The first branch takes into account elastic-plastic behaviour. The yield stress is given by a parabolic criterion, characterized using compressive, tensile and tri-axial tests. The hardening is isotropic and the plastic flow rule is nonassociated. The other branches are viscoelastic. A genetic algorithm is used to optimise the viscoelastic parameters, previously obtained using DMA measurements. Comparisons between the model and experiments are proposed for different temperatures, strain rates and pressures. At last, a user material subroutine has been developed in Abaqus Standard and finite element computations of the Brazilian test are compared to the experimental response. Keywords: energetic material, parabolic plastic criterion, genetic algorithm, DMA, viscoelasticity, Isotropic damage, Brazilian tests.

Lecture Notes in Mechanical Engineering, 2013

ABSTRACT The opening-closing effect of the microcracks is a kinematic phenomenon usually modeled ... more ABSTRACT The opening-closing effect of the microcracks is a kinematic phenomenon usually modeled using a set of damage variables. The influence of microcracks must be taken into account depending on their opening or closing state, which results in different elasticity for the same level of damage. In this work, the volumetric, deviatoric and tangential model denoted as V-D-T is chosen and modified by introducing the opening-closing effect into the free energy. This model is coupled with a sliding-friction mechanism of the microcrack lips when the latter are closed. Simulations of compression tests with confinements are presented to validate the model.

Engineering Fracture Mechanics, 2014

ABSTRACT Modelling the behaviour of quasi-brittle materials requires dealing with the anisotropic... more ABSTRACT Modelling the behaviour of quasi-brittle materials requires dealing with the anisotropic damage evolution induced by the loading direction and the unilateral effect corresponding to the sudden opening/closure of defects. The latter was the cause deficiencies of some constitutive laws as a no continuous stress/strain response or spurious energy dissipation. In this paper, the behaviour of pressed high explosive is experimentally investigated. Evidences of a pre-existing damage, an anisotropic one developing during loading and the unilateral effect are detailed. The framework of the microplane constitutive laws previously proposed in the literature and based on the volumetric-deviatoric-tangential strain projections is used. Damage is introduced in the model and is affected by an "effectiveness" function weighting its influence with the loading direction. The calibration procedure is detailed and a discussion enables highlighting the strengths and weaknesses of the modelling approach.