Dissertations / Theses on the topic 'Modélisation hyperélastique'
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Jazzar, Mohamad Fadl. "Modélisation du comportement hyperélastique quasi incompressible de structures acier-élastomères et validation expérimentale." Aix-Marseille 2, 1993. http://www.theses.fr/1993AIX22085.
Full textMasson, Ingrid. "Contribution à la modélisation mécanique du comportement dynamique, hyperélastique et anisotrope de la paroi artérielle." Phd thesis, Université Paris-Est, 2008. http://tel.archives-ouvertes.fr/tel-00461684.
Full textFigueredo, Rémi. "Modélisation numérique du comportement hyperélastique-endommagement : application à la mise en forme des structures caoutchoutiques." Troyes, 2010. http://www.theses.fr/2010TROY0003.
Full textThe rubbery environments present the same mechanical behaviour as hyperelastic or viscohyperelastic solids. The finite deformation of these materials often generate microscopic and voluminal defects leading to the creation of micro-cracks inside the structure. This study deals with the constitutive modelling of the mechanical response of filled-elastomer materials. In the framework of Continuum Damage Mechanics, the formulation is based on the decomposition of the gradient of de-formation into a nearly-incompressible elastic part and an irreversible and compressible dam-age part induced by an isotropic variable. The proposed approach is generalized to iso-tropic behaviour of elastomer using classical energy densities as the Ogden form. The local integration is outlined thanks to the Newton iterative scheme applied to a reduced system of one equation after some numerical assumptions. The proposed model is integrated in ABAQUS code via user’s subroutine. Some numerical examples are presented to discuss the capability of the coupled non linear hyperelastic model to predict isotropic ductile damage initiation and growth during forming processes of filled-elastomer using or not remeshing procedure
Nguessong, Nkenfack Alain. "Modélisation ds matériaux caoutchouteux par une nouvelle densité hyperélastique isotrope hybride - Théorie et implémentation éléments finis." Thesis, Belfort-Montbéliard, 2015. http://www.theses.fr/2015BELF0257/document.
Full textThis thesis concerns the development of a new incompressible isotropic hyperelastic behavior law allowing the modeling of rubber materials with large strain and large displacement. This new law mixes a molecular approach with a phenomenological one and therefore covers a wide range of loading. It has been built by a sum over four terms:– a term related to the interleaving macromolecular chains observed with the crystallization phenomenon. This term is modeled by a logarithmic function coming from the phenomenological energy of Gent-Thomas,– a term related to the assumption of affine deformations observed with the final stiffening of a part of macromolecular elastomeric chains. This term comes from the non Gaussian probability of Langevin. We have modeled it by the 8-chains molecular law of Arruda-Boyce but with an original approximation of the inverse of the Langevin function,– a term related to the stress occurring with non affine strains. This term has been modeled by a Gaussian function adopting an integral form. This is one of the original contribution of this thesis work,– a classical volumetric term taking into account the incompressibility of the material.The two main originalities of the thesis are therefore the introduction of a new approximation of the inverse of the Langevin function and the development of a new hyperelastic energy density which is isotropic, incompressible and hybrid.In order to study the efficiency of the proposed model, comparisons were made with several experimental data available in the literature. These comparisons have been successful and we have implemented our model in the university finite element software FER
Baquet, Erwan. "Modélisation thermomécanique visco-hyperélastique du comportement d'un polymère semi-cristallin : application au cas d'une matrice polyamide 6.6." Phd thesis, École Nationale Supérieure des Mines de Paris, 2011. http://pastel.archives-ouvertes.fr/pastel-00715693.
Full textLuo, Yun Mei, and Yun Mei Luo. "Modélisation thermo-visco-hyperélastique du comportement du PET dans les conditions de vitesse et de température du procédé de soufflage." Phd thesis, Université Paris-Est, 2012. http://tel.archives-ouvertes.fr/tel-00807799.
Full textLuo, Yun Mei. "Modélisation thermo-visco-hyperélastique du comportement du PET dans les conditions de vitesse et de température du procédé de soufflage." Thesis, Paris Est, 2012. http://www.theses.fr/2012PEST1146/document.
Full textThe stretch blow moulding process for polyethylene terephthalate (PET) bottles generates important modifications of the mechanical properties of the material as it can be shown in an identification study of the orthotropic and heterogeneous elastic properties in the 3D region of the petaloïd bottom of PET bottles. The main topic of this work deals with the modelling of the complex behaviour of the PET during the process that is managed at a temperature slightly above the glass transition temperature Tg. In this range of temperature and considering the high strain rates involved during the process, large changes in the material morphology can be observed and the goal of this work is to propose a visco hyperelastic model to predict the PET behaviour under these severe conditions: large deformations, high strain rate… An original procedure is proposed to manage the identification of the material properties from the experimental data of recent biaxial elongation tests. On the other hand, effects of temperature are of fundamental importance during the injection stretch blow moulding process of PET bottles. Near Tg small variations of temperature have great influence on physical properties: an accurate prediction of the initial temperature field generated by the infrared heating is proposed. Also, the important viscous dissipation induces self-heating of the material during the process which is necessary to be taken into account during the numerical simulation. The identification of the thermal parameters is achieved by an experimental infrared heating study. The global thermo mechanical model is implemented and numerical simulations are managed using the finite element method to solve the free blowing of PET preforms
Diouf, Edouard. "Modélisation mécanique du comportement hyperélastique, anisotrope, compressible et dynamique d'une structure tubulaire épaisse : application à l'artère carotide et aux substituts vasculaires." Paris 12, 2005. http://www.theses.fr/2005PA120070.
Full textCardiovascular diseases represent the first cause of mortality in the developed countries, for this reason study of the arteiral structures and their prosthetic substitute take an important place in the fields of biomedical research. In this work, we propose a mechanical model to study the dynamic behavior of a tubular structure made of a hyperelastic, anisotropic, compressible and prestressed material. We have first formulated at boundaries values problem of the mechanical behavior of the arterial wall carotid submitted to conditions that mimics in-vivo conditions. The equations of this model were solved numerically by the method of Runge-Kutta at the fourth order. The intraluminal pressures distributions obtained were compared to the experimental measurements obtained both on healthy subject and on patients with the elastic PseudoXanthome (PXE) disease. These results show that (i) the compressible character of the arterial wall, observed in some healthy subject, influences the distributions of parietal stress and (ii) that the PXE disease modifies some mechanical characteristics of the arterial wall like the compliance and the shear modulus. In a second approach, we have formulated the above theoretical model to study a vascular prosthesis prototype of small diameter submitted to an azimutal shear. Results show that kinematics of deformation reproduce the effects of the azimutal shear generated before and after surgery. The obtained analytical solution made possible the evaluation of the anisotropy and the prestressed effects on the dynamic distributions of stress in the prosthetic structure. This approach will make possible the evaluation of the cardiovascular prosthesis and will lead to improve prosthesis prototype in term of mechanical properties and designing
Soulimane, Sofiane. "Conception et modélisation d'un micro-actionneur à base d'élastomère diélectrique." Phd thesis, Université Paul Sabatier - Toulouse III, 2010. http://tel.archives-ouvertes.fr/tel-00546239.
Full textCharmetant, Adrien. "Approches hyperélastiques pour la modélisation du comportement mécanique de préformes tissées de composites." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00706212.
Full textJu, Minglei. "Contribution à la modélisation du comportement visco-hyper-élastique de mousses de polyuréthane : Validation expérimentale en quasi-statique." Thesis, Mulhouse, 2014. http://www.theses.fr/2014MULH8865/document.
Full textFlexible polyurethane foam is widely used in numerous applications such as acoustic, thermal and building due to its low density and its ability to absorb thermal and acoustic energy. It is also used for the comfort of the seats such as the vehicle, train, plane due to its low stiffness and its ability to absorb deformation energy. In order to optimize the comfort of the car seat, it is necessary to model the behavior of seat system, particularly the flexible component - polyurethane foam. The main objective of this study is to identify and model the quasi-static behavior of polyurethane foam under different test conditions in large deformations. Compression / decompression uniaxial unicycle and multicycle tests were carried out on three types of polyurethane foam at different strain rates, which allows us to understand the behavior of the material. The results of the tests indicate that the polyurethane foams exhibit a hyperelastic behavior and a viscoelastic behavior under large deformations. They also showed that the polyurethane foams have a stress softening phenomenon which is called 'Mullins effect' during the compression / decompression multicycle tests. In other words, the stress in first cycle is lower than the stresses in the subsequent cycles in the same deformation. ‘Mullins effect’ for the polyurethane foam is also an important study in this dissertation. Based on the experimental results and the goal of modeling quasi-static behavior of the polyurethane foam, three visco-hyperelastic models were developed. These models consist in two elements: hyperelastic models, which is normally used for description the behavior of rubber materials, and entire memory model which takes into account the history and describing the viscoelastic behavior. Model parameters were identified using appropriate identification and optimization methods. The results of modeling the mechanical behavior of the foam on the unicycle and multicycle tests were compared with experimental results. The models showed a very good competence to simulate the first cycle and the following cycles during the charge / discharge tests. Our models have proven its ability to model Mullins effect on flexible polyurethane foams. These models have been validated on three types of foam in order to present a comparative study of their effectiveness and their representativeness
Tran, Hung Viet. "Caractérisation des propriétés mécaniques de la peau humaine in vivo via l'IRM." Compiègne, 2007. http://www.theses.fr/2007COMP1698.
Full textThe skin is a complex material, consists of three layers (epidermis, dermis and hypodermis) and lies on muscle. The combination of an indentation and MRI techniques has been developed. Indentation tests were performed on the left forearm of 9 subjects (from 26 to 40 years-olds). The images from MRI were processed via images processing software developed in house. FE Modeling trom the MRI images was conducted through MSC. Patran pre-processor and MSC. Marc solver. The NeoHooke hyperelastic incompressible constitutive law (ClO) has been used. The parameters identification of constitutive law was performed through Levenberg-Marquardt minimization algorithm. The numerical validation showed that the minimum is unique when the epidermis and dermis behave as one layer. The results of identification for a population of 9 subjects are: ClO,E+D=[60-370] kPa; CIO,Hyp. =[0. 04-4] kPa; ClO,Mus. =[0. 7-1. 7] kPa
Donnard, Adrien. "Etude du comportement mécanique multiaxial de matériaux cellulaires." Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0026/document.
Full textThis thesis is focused on the mechanical behavior of foam designed to absorb energy in an airplane pilot seat cushion. Usually, these materials are characterized using uniaxial compressive test. Nevertheless, this uniaxial characterization doesn’t represent the real in-use loading of cushion. To complete these data, this work focuses on multiaxial behavior characterization of foam. The analysis of behavior is realized by using a separation into two contributions linked to the volume (pressure-volume) and the shape (distortion-shear) change. A hydrostatic testing system was developed with the aim to characterize the volume change behavior. Results highlight a strong influence of the volume change behavior during an uniaxial compression solicitation. A second testing system was developed allowing to apply radial solicitations following a kinematic angle, which imposes a non-proportional variation of volume and distortion. A kinematic angle influence is observed on the volume and shape change behavior. Other solicitations composed of compression and shear applied in a sequential way, permit to observe a volume influence on the shape change behavior. Finally, a 2D simulation model composed of 1D element composition shows a good representation of the volume and shape changes behavior obtained from experimentation
Carcan, Alain. "Modélisation des grandes déformations axisymétriques de membranes minces hyperélastiques incompressibles." Compiègne, 1985. http://www.theses.fr/1985COMPS134.
Full textWang, Jie. "Simulation macro-méso de la mise en forme de renforts tissés interlocks." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI075.
Full textThe forming stage in the RTM process is crucial because it strongly influences the mechanical behavior of composites in service. In order to better predict the appearance of possible defects of composite materials, numerical simulations are increasingly developed taking into account the duration and the cost of experiences. Deformations and orientations of yarns at the mesoscopic scale are essential to simulate the resin flow in the stage of injection. Given the number of elements and their complex interactions, it is difficult to conduct the shaping simulations for the entire reinforcement at this mesoscopic scale. This present thesis consists in developing a multiscale method that allows linking the macroscopic simulations of reinforcements and the mesoscopic modellings of RVE (representative volume element) during the forming process. Firstly, the numerical simulations for three different woven reinforcements at the macroscopic scale are carried out using an anisotropic hyperelastic constitutive law, by the finite element method with a dynamic explicit scheme. Then, the geometrical modelling of RVE at the mesoscopic scale are reconstituted based on the tomographic images. The mesoscopic displacement-deformation fields of woven reinforcements are determined from the macroscopic results and the position of the yarns. In order to take into consideration sliding effects of yarns, two approaches of mesoscopic simulations of RVE are developed. Finally, the mesoscopic numerical results are compared with the experimental results
Touboul, Marion. "Approche multi-échelles morphologique et directe pour une classe de composites particulaires fortement chargés hyperélastiques et viscohyperélastiques." Poitiers, 2007. http://www.theses.fr/2007POIT2300.
Full textThis study is devoted to multi-scale modelling of a wide class of highly-filled particulate composites such as solid propellants. Inspired by the previous work of Christoffersen (1983), the approach at stake (MA) is based on a preliminary geometrical and kinematical schematization. The objective of this work can be split into two parts : proving the ability of the MA to deal with viscohyperelasticity (behaviour of solid propellants’ elastomeric matrix) and evaluating its quantitative relevance. The first point is treated by applying the MA to a numerically generated composite with random microstructure and viscohyperelastic matrix. The localisation-homogenisation problem is solved in a direct manner thanks to a particular algorithm operating in real time-space domain. Qualitative results are obtained. Concerning the second point, comparisons between MA estimates and finite element (FE) results (global and local levels) are made in order to evaluate the effects of the kinematical hypotheses relative to the MA. These comparisons are made on periodic microstructures (simple and involved) satisfying the MA geometrical schematisation, for hyperelastic ant viscohyperelastic constituents. Some advantages and weaknesses to be improved are highlighted. Finally, a transversal program aiming at confronting MA estimates to experimental and FE results on a real propellant is elaborated. Each step –experimental tests on the composite and its phases, morphological characterisation via tomography, automatic FE meshing of real microstructure, determination of the RVE (a few hundred of grains) relative to both methods (MA and FE)– is detailed and prospective works are presented
Lacour, Thomas. "Modélisation de la vaporisation acoustique de gouttelettes micro- ou nano-métriques encapsulées par des coques hyperélastiques ou des tensio-actifs." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS469.
Full textNanodroplets have great, promising medical applications such as contrast imaging, embolotherapy or targeted drug delivery. Their functions can be mechanically activated by means of focused ultrasound inducing a phase change of the inner liquid known as acoustic droplet vaporization (ADV) process. In this context, a four-phases (vapor+liquid+surfactant layer+surrounding environment) model of ADV is proposed. Attention is especially devoted to the large but finite deformation expected after the complete vaporization of the inner liquid. Two kinds of encapsulation are considered: a viscoelastic shell (linear viscosity and hyperelasticity) and a surfactants membrane (dynamical surface tension). Various responses to ultrasound excitation are illustrated, depending on surfactant properties and acoustical excitation parameters. Different classes of ADV outcomes are exhibited within a phase diagram, and a relevant threshold ensuring complete vaporization is defined. The dependence of this threshold with acoustical, geometrical and mechanical parameters is also discussed. Finaly, an optimum point is highlighted in the context of medical applications
Ramaël, Bruno. "Caractérisation in situ des propriétés mécaniques des parois vasculaires par une technique non invasive." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2314/document.
Full textThis thesis is based on identifying the mechanical properties of facial arteries. It is part of FlowFace project, which focuses on the study of the facial arterial system by MRI imaging. It is based on a measurement campaign conducted on a sample of 30 people at the Hospital of Amiens, which allowed obtaining noninvasively the evolution of the blood vessel deformation and the measurement of the flow. Diastolic and systolic pressures were measured at the arm independently of the MRI measurements. The aim of the thesis was to model the deformation of blood vessels and to implement an optimization technique to determine their mechanical properties by inverse analysis using MRI measurements of deformation. Simulations of the behavior of the blood vessels were performed, using ANSYS Inc. software, modeling fluid-structure interactions both strong and weak coupling. The objective was to determine the parietal deformations induced by hemodynamic conditions and pressure drops in the vessels concerned. The simulations involved hyperelastic and large deflection models to simulate the behavior of the wall. They allow calculate the numerical displacements that we compared with experimental displacements measured by MRI, the aim is that the difference between numerical and experimental be as low as possible to deduce the adequate mechanical parameters for the artery. To identify the mechanical properties of the vessels, the optimization technique proposed in ANSYS based on genetic algorithms or gradient algorithms was used. The identification method was validated on cylindrical tubes (elastomer), for which deformation measurements were acquired by MRI imaging under pulsating flow. The values of mechanical properties determined were compared with those obtained by traction tests and dilatation tests. One of the crucial points of identification involves the determination of the non-stress state. If it is a known parameter for the elastic tube, it has to be determining for blood vessels. The challenge of this thesis is to determine from a "minimum" quantity of pressure and deformation information, the hyper-elastic properties of blood vessels. The method based on a patient-specific geometry deformation concluded that the tangent modulus in diastole is approximately 200kPa while that in systole is in a range of 300 kPa to 1 MPa
Touboul, Marion. "Approche multi-échelles morphologique et directe pour une classe de composites particulaires fortement chargés hyperélastiques et visco-hyperélastiques." Phd thesis, 2007. http://tel.archives-ouvertes.fr/tel-00451829.
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