Literatura académica sobre el tema "Murnaghan hyperelastic material model"
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Artículos de revistas sobre el tema "Murnaghan hyperelastic material model"
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Jemioło, Stanisław y Aleksander Franus. "Numerical implementation of the Murnaghan material model in ABAQUS/Standard". MATEC Web of Conferences 196 (2018): 01042. http://dx.doi.org/10.1051/matecconf/201819601042.
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The paper presents a numerical implementation of the Murnaghan material model (M) [1] in the finite element method software ABAQUS / Standard v. 6.14 [2]. The UHYPER user subroutine is employed, which is suitable for the class of isotropic hyperelastic models [3]. As a special case of the M model, the Saint Venant-Kirchhoff (SVK) model is considered [4]. Formal verification on the basis of elementary tests is performed. Among others, a special attention is paid to a simple shear deformation. In all tested types of deformation, analytical values confirms results based on the finite element procedure within assumed numerical precision and accuracy. It should be noted that the stored-energy function of the M and SVK models do not meet any requirements of the mathematical theory of non-linear elasticity [4, 5]. Therefore, these models are suitable for relatively small deformations, while there are no restrictions on finite rotations. As an example of applications, a tube under axial compression is considered in two cases. Various starting parameters for the Riks procedure [6, 7] are adopted to obtain different solutions of corresponding boundary value problem. Material parameters of steel are considered according to Lurie [8].
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Rushchitsky, J. J. "On the Constants of the Nonlinear Murnaghan’s Hyperelastic Material Model". International Applied Mechanics 52, n.º 5 (septiembre de 2016): 508–19. http://dx.doi.org/10.1007/s10778-016-0771-5.
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Yuan, Maodan, Anbang Dai, Lin Liao, Yan Chen y Xuanrong Ji. "Numerical Study on Surface Roughness Measurement Based on Nonlinear Ultrasonics in Through-Transmission and Pulse-Echo Modes". Materials 14, n.º 17 (26 de agosto de 2021): 4855. http://dx.doi.org/10.3390/ma14174855.
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Ultrasonic is one of the well-known methods for surface roughness measurement, but small roughness will only lead to a subtle variation of transmission or reflection. To explore sensitive techniques for surfaces with small roughness, nonlinear ultrasonic measurement in through-transmission and pulse-echo modes was proposed and studied based on an effective unit-cell finite element (FE) model. Higher harmonic generation in solids was realized by applying the Murnaghan hyperelastic material model. This FE model was verified by comparing the absolute value of the nonlinearity parameter with the analytical solution. Then, random surfaces with different roughness values ranging from 0 μm to 200 μm were repeatedly generated and studied in the two modes. The through-transmission mode is very suitable to measure the surfaces with roughness as small as 3% of the wavelength. The pulse-echo mode is sensitive and effective to measure the surface roughness ranging from 0.78% to 5.47% of the wavelength. This study offers a potential nondestructive testing and monitoring method for the interfaces or inner surfaces of the in-service structures.
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Zhao, Chengwei, Sunia Tanweer, Jian Li, Min Lin, Xiang Zhang y Yang Liu. "Nonlinear Guided Wave Tomography for Detection and Evaluation of Early-Life Material Degradation in Plates". Sensors 21, n.º 16 (16 de agosto de 2021): 5498. http://dx.doi.org/10.3390/s21165498.
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In this paper, the possibility of using nonlinear ultrasonic guided waves for early-life material degradation in metal plates is investigated through both computational modeling and study. The analysis of the second harmonics of Lamb waves in a free boundary aluminum plate, and the internal resonance conditions between the Lamb wave primary modes and the second harmonics are investigated. Subsequently, Murnaghan’s hyperelastic model is implemented in a finite element (FE) analysis to study the response of aluminum plates subjected to a 60 kHz Hanning-windowed tone burst. Different stages of material degradation are reflected as the changes in the third order elastic constants (TOECs) of the Murnaghan’s model. The reconstructed degradations match the actual ones well across various degrees of degradation. The effects of several relevant factors on the accuracy of reconstructions are also discussed.
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Jemiolo, Stanislaw, Aleksander Franus y Wlodzimierz Domanski. "Attempt to Assess the Scope of Applicability of a Hyperelastic Murnaghan’s Material Model in the Case of Elastomers". IOP Conference Series: Materials Science and Engineering 661 (20 de noviembre de 2019): 012040. http://dx.doi.org/10.1088/1757-899x/661/1/012040.
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Major, Izabela y Maciej Major. "Application of the Perturbation Method for Determination of Eigenvalues and Eigenvectors for the Assumed Static Strain". Civil and Environmental Engineering 10, n.º 2 (1 de diciembre de 2014): 111–20. http://dx.doi.org/10.2478/cee-2014-0020.
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Abstract The paper presents the perturbation method which was used for computation of eigenvalues and eigenvectors for the assumed homogeneous state of strain in the hyperelastic Murnaghan material. The values calculated might be used for determination of the rate of propagation of unit vectors of wave amplitude for other non-linear
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Соколова, Марина Юрьевна y Юрий Владимирович Астапов. "Elastic waves in the Hencky-Murnaghan material". Вестник Чувашского государственного педагогического университета им. И.Я. Яковлева. Серия: Механика предельного состояния, n.º 3(45) (29 de diciembre de 2020): 108–20. http://dx.doi.org/10.37972/chgpu.2020.26.33.011.
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Рассмотрены динамические методы идентификации модели нелинейно упругого деформируемого тела. По эффективным фазовым скоростям продольных и поперечных волн, распространяющихся вдоль и поперек оси сжимаемого стержня, возможно определить пять констант упругости второго и третьего порядков, входящих в соотношения модели. В статье получены расчетные формулы и приведен пример определения зависимости фазовых скоростей для полиамида 6. The dynamic methods for selecting models of a nonlinear elastic deformable body are considered. Depending on the model, five elastic constants of the second and third orders, which are available in the relations of the models, can be determined. The calculation formulas and the given example of determining the dependence of phase velocities for polyamide 6 are obtained in the article.
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Соколова, Марина Юрьевна y Юрий Владимирович Астапов. "Elastic waves in the Hencky-Murnaghan material". Вестник Чувашского государственного педагогического университета им. И.Я. Яковлева. Серия: Механика предельного состояния, n.º 3(45) (29 de diciembre de 2020): 108–20. http://dx.doi.org/10.37972/chgpu.2020.26.33.011.
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Рассмотрены динамические методы идентификации модели нелинейно упругого деформируемого тела. По эффективным фазовым скоростям продольных и поперечных волн, распространяющихся вдоль и поперек оси сжимаемого стержня, возможно определить пять констант упругости второго и третьего порядков, входящих в соотношения модели. В статье получены расчетные формулы и приведен пример определения зависимости фазовых скоростей для полиамида 6. The dynamic methods for selecting models of a nonlinear elastic deformable body are considered. Depending on the model, five elastic constants of the second and third orders, which are available in the relations of the models, can be determined. The calculation formulas and the given example of determining the dependence of phase velocities for polyamide 6 are obtained in the article.
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Rugsaj, Ravivat y Chakrit Suvanjumrat. "Finite Element Analysis of Hyperelastic Material Model for Non-Pneumatic Tire". Key Engineering Materials 775 (agosto de 2018): 554–59. http://dx.doi.org/10.4028/www.scientific.net/kem.775.554.
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This research aimed to find an appropriated hyperelastic material model for the finite element analysis (FEA) of a non-pneumatic tire (NPT). The innovative method involving water jet cutting technique was performed to prepare the tensile and compressive test specimens from the non-pneumatic tire, TWEEL, which was developed by Michelin. The stress-strain relationship of material testing results was fitted to select the suitable constitutive model. The FEA was performed and compared to the physical experiment to validate the hyperelastic material model. The suitable hyperelastic material model can be used in the development of NPT for the further work.
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Sumelka, Wojciech y George Z. Voyiadjis. "A hyperelastic fractional damage material model with memory". International Journal of Solids and Structures 124 (octubre de 2017): 151–60. http://dx.doi.org/10.1016/j.ijsolstr.2017.06.024.
Texto completoTesis sobre el tema "Murnaghan hyperelastic material model"
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Chlebek, David. "Simulation of ultrasonic time of flight in bolted joints". Thesis, KTH, Hållfasthetslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298342.
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Ultrasonic measurements of the preload in bolted joints is a very accurate method since it does not depend on the friction and other factors which cause difficulties for common methods. The ultrasonic method works by emitting an ultrasonic pulse into the bolt which is reflected at the end and returned to the transducer, the change in the time of flight (TOF) can be related to the elongation of the bolt and therefore the preload. One must account for the acoustoelastic effect which is the change in sound speed due to an initial stress state. The goal of this thesis project was to implement a Murnaghan hyperelastic material model in order to account for the acoustoelastic effect when conducting a numerical simulation using the finite element method (FEM). An experiment was also performed to validate the numerical simulation. The DeltaTOF as a function of a tensile force was obtained for an M8 and M10 test piece from the experiment. The material model was implemented by creating a user subroutine written in Fortran for the explicit solver Radioss. Hypermesh was used to set-up the numerical simulation. The material model has shown an expected behavior with an increased sound speed with compressive stresses and a decreased speed with tensile stresses. The numerical simulation showed a good correspondence to the experimental results.Ultraljudsmätning av klämklraften i skruvförband är en väldigt noggrann metod eftersom att metoden inte påverkas av friktion eller andra faktorer som innebär svårigheter för vanliga metoder. Ultraljudsmetoden fungerar genom att skicka in en ultraljudsvåg i skruven som reflekteras i botten och återvänder tillbaka till sensorn. Skillnaden i tiden för ekot att återvända kan relateras till förlängningen av skruven och därmed klämkraften. Det är viktigt att ta hänsyn till den akustoelastiska effekten, som är fenomenet där ljudhastigheten av en våg i en solid förändras med spänningstillståndet. Målet med det här arbetet är att implementera en hyperelastisk Murnaghan modell som tar hänsyn till den akustoelastiska effekten med FEM simuleringar. Ett experiment har också genomförts för att validera beräkningsmodellen. Tidsfördröjningen som en funktion av förspänningskraften togs fram för ett M8 och M10 provobjekt. Murnaghans hyperelastiska materialmodell implementerades genom att skapa ett användar material skriven i programmeringsspråket Fortran för den explicita lösaren Radioss. Hypermesh användes för att ställa upp FEM simuleringen. Materialmodellen har visat ett väntat beteende med en ökad ljudhastighet med tryckspänningar och minskad ljudhastighet med dragspänningar. Beräkningsmodellen visade en god överenstämmelse med resultatet från experimentet.
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TRIPATHY, SAKYASINGH. "EXTRACTION OF NON-LINEAR MATERIAL PROPERTIES OF BIO-GELS USING ATOMIC FORCE MICROSCOPY". University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123381089.
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Hu, Lianxin. "Micromechanics of granular materials : Modeling anisotropy by a hyperelastic-plastic model". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI133.
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Afin de modéliser le comportement des géométariaux sous des charges complexes, plusieurs études et travaux expérimentaux ont été réalisées afin d’établir des modèles constitutifs relatifs. Une caractéristique importante des matériaux granulaires est que la relation entre la contrainte et la déformation et ce même dans le domaine élastique n’est pas linéaire, contrairement aux réponses du métal. Il a également été constaté que la réponse contrainte-déformation des matériaux granulaires montre les caractéristiques de l’anisotropie induite, ainsi que les non-linéarités. En outre, l’anisotropie induite par la contrainte se produit pendant le processus de chargement sur les sols, par exemple, les charges ou les déplacements. Dans ce travail, un nouveau modèle qui est une combinaison de modèle hyperélastique Houlsby et modèle élastoplastique Plasol a été proposé. Ce nouveau modèle a pris en compte la réponse non linéaire de la contrainte dans le domaine élastique et plastique, et l’élasticité anisotrope a également été bien considérée. En outre, les problèmes de l’écoulement de la déformation plastique a été calibré par un algorithme d’intégration approprié. Plus tard, le nouveau modèle a été vérifié en utilisant la méthode numérique et comparé aux expériences de laboratoire dans des conditions triaxiales axisymmétriques. Les résultats de comparaison ont montré un bon effet de simulation du nouveau modèle qui a juste utilisé un seul ensemble de paramètres pour un sol spécifique dans différentes situations de contraintes. Ensuite, l’analyse de la nouvelle variable interne du modèle, c’est-à-dire l’exposant de pression, a montré que la valeur de l’exposant de pression qui correspond au degré d’anisotropie a eu un effet évident sur la réponse contrainte-déformation. De plus, ce type d’effet est également affecté par la densité et l’état de drainage des échantillons. En s’appuyant sur un nouveau modèle, un facteur de sécurité qui fait référence au critère de travail de deuxième ordre a été adopté et testé dans un modèle axisymétrique et un modèle de pente réel. Il a montré que la valeur négative ou la diminution spectaculaire du travail global normalisé de second ordre se produit lors d’une défaillance locale ou globale avec apparition d’énergie cinétique. Cette caractéristique du travail du second ordre peut également être affectée par l’exposant à pression variable. Enfin, un nouveau modèle a également été comparé à un modèle élastoplastique qui considère à la fois l’anisotropie élastique et la dilatation anisotrope, c’est-à-dire le modèle SANISAND modifié. Les avantages et les inconvénients ont été illustrés dans les résultats de comparaisonIn order to model the behavior of geometarials under complex loadings, several researches have done numerous experimental works and established relative constitutive models for decades. An important feature of granular materials is that the relationship between stress and strain especially in elastic domain is not linear, unlike the responses of typical metal or rubber. It has been also found that the stress-strain response of granular materials shows the characteristics of cross-anisotropy, as well as the non-linearities. Besides, the stress-induced anisotropy occurs expectedly during the process of disturbance on soils, for example, the loads or displacements. In this work, a new model which is a combination of Houlsby hyperelastic model and elastoplastic Plasol model was proposed. This new model took into account the non-linear response of stress and strain in both elastic and plastic domain, and the anisotropic elasticity was also well considered. Moreover, the overflow problem of plastic strain in plastic part was calibrated by a proper integration algorithm. Later, new model was verified by using numerical method and compared with laboratory experiments in axisymmetric triaxial conditions. The comparison results showed a good simulation effect of new model which just used one single set of parameters for a specific soil in different confining pressure situations. Then the analysis of new model internal variable, i.e., pressure exponent, illustrated that the value of pressure exponent which corresponds to the degree of anisotropy had an obvious effect on the stress-strain response. Moreover, this kind of effect is also affected by the density and drainage condition of samples. Basing on new model, a safety factor which refers to the second-order work criterion was adopted and tested in axisymmetric model and actual slope model. It showed that the negative value or dramatic decreasing of global normalized second-order work occurs accompanying with a local or global failure with a burst of kinetic energy. This feature of second-order work can also be affected by the variable pressure exponent. At last, new model was also compared with an elastoplastic model which considers both anisotropic elastic and anisotropic dilatancy, i.e., modified SANISAND model. Both advantages and disadvantages were illustrated in the comparison results
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Little, Judith Paige. "Finite Element Modelling Of Anular Lesions in the Lumbar Intervertebral Disc". Queensland University of Technology, 2004. http://eprints.qut.edu.au/15952/.
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Low back pain is an ailment that affects a significant portion of the community. However, due to the complexity of the spine, which is a series of interconnected joints, and the loading conditions applied to these joints the causes for back pain are not well understood. Investigations of damage or failure of the spinal structures from a mechanical viewpoint may be viewed as a way of providing valuable information for the causes of back pain. Low back pain is commonly associated with injury to, or degeneration of, the intervertebral discs and involves the presence of tears or lesions in the anular disc material. The aim of the study presented in this thesis was to investigate the biomechanical effect of anular lesions on disc function using a finite element model of the L4/5 lumbar intervertebral disc.
The intervertebral disc consists of three main components - the anulus fibrosus, the nucleus pulposus and the cartilaginous endplates. The anulus fibrosus is comprised of collagen fibres embedded in a ground substance while the nucleus is a gelatinous material. The components of the intervertebral disc were represented in the model together with the longitudinal ligaments that are attached to the anterior and posterior surface of the disc. All other bony and ligamentous structures were simulated through the loading and boundary conditions.
A high level of both geometric and material accuracy was required to produce a physically realistic finite element model. The geometry of the model was derived from images of cadaveric human discs and published data on the in vivo configuration of the L4/5 disc. Material properties for the components were extracted from the existing literature. The anulus ground substance was represented as a Mooney-Rivlin hyperelastic material, the nucleus pulposus was modelled as a hydrostatic fluid in the healthy disc models and the cartilaginous endplates, collagen fibres and longitudinal ligaments were represented as linear elastic materials. A preliminary model was developed to assess the accuracy of the geometry and material properties of the disc components. It was found that the material parameters defined for the anulus ground substance did not accurately describe the nonlinear shear behaviour of the tissue. Accurate representation this nonlinear behaviour was thought to be important in ensuring the deformations observed in the anulus fibrosus of the finite element model were correct.
There was no information found in the literature on the mechanical properties of the anulus ground substance. Experimentation was, therefore, carried out on specimens of sheep anulus fibrosus in order to quantify the mechanical response of the ground substance. Two testing protocols were employed. The first series of tests were undertaken to provide information on the strain required to initiate permanent damage in the ground substance. The second series of tests resulted in the acquisition of data on the mechanical response of the tissue to repeated loading. The results of the experimentation carried out to determine the strain necessary to initiate permanent damage suggested that during daily loading some derangement might be caused in the anulus ground substance. The results for the mechanical response of the tissue were used to determine hyperelastic constants which were incorporated in the finite element model. A second order Polynomial and a third order Ogden strain energy equation were used to define the anulus ground substance. Both these strain energy equations incorporated the nonlinear mechanical response of the tissue during shear loading conditions.
Using these geometric data and material properties a finite element model of a representative L4/5 intervertebral disc was developed.
When the measured material parameters for the anulus ground substance were implemented in the finite element model, large deformations were observed in the anulus fibrosus and excessive nucleus pressures were found. This suggested that the material parameters defining the anulus ground substance were overly compliant and in turn, implied the possibility that the stiffness of the sheep anulus ground substance was lower than the stiffness of the human tissue. Even so, the mechanical properties of the sheep joints had been shown to be similar to those of the human joint and it was concluded that the results of analyses using these parameters would provide valuable qualitative information on the disc mechanics.
To represent the degeneration of the anulus fibrosus, the models included simulations of anular lesions - rim, radial and circumferential lesions. Degeneration of the nucleus may be characterised by a significant reduction in the hydrostatic nucleus pressure and a loss of hydration. This was simulated by removal of the hydrostatic nucleus pressure.
Analyses were carried out using rotational loading conditions that were comparable to the ranges of motion observed physiologically. The results of these analyses showed that the removal of the hydrostatic nucleus pressure from an otherwise healthy disc resulted in a significant reduction in the stiffness of the disc. This indicated that when the nucleus pulposus is extremely degenerate, it offers no resistance to the deformation of the anulus and the mechanics of the disc are significantly changed. Specifically, the resistance to rotation offered by the intervertebral disc is reduced, which may affect the stability of the joint. When anular lesions were simulated in the finite element model they caused minimal changes in the peak moments resisted by the disc under rotational loading. This suggested that the removal of the nucleus pressure had a greater effect on the mechanics of the disc than the simulation of anular lesions.
The results of the finite element model reproduced trends observed in both the healthy and degenerate intervertebral disc in terms of variations in nucleus pressure with loading conditions, axial displacement of the superior surface and bulge of the peripheral anulus. It was hypothesised that the reduced rotational stiffness of the degenerate disc may result in overload of the surrounding innervated osseoligamentous anatomy which may in turn cause back pain. Similarly back pain may result from the abnormal deformation of the innervated peripheral anulus in the vicinity of anular lesions. Furthermore, it was hypothesised that biochemical changes may result in the degeneration of the nucleus, which in turn may cause excessive strains in the anulus ground substance and lead to the initiation of permanent damage in the form of anular lesions. With further refinement of the components of the model and the methods used to define the anular lesions it was considered that this model would provide a powerful analysis tool for the investigation of the mechanics of intervertebral discs with and without significant degeneration.
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Silva, Renato de Sousa e. "Estudo do comportamento dinâmico de membranas retangulares hiperelásticas". Universidade Federal de Goiás, 2015. http://repositorio.bc.ufg.br/tede/handle/tede/4809.
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Structural elements with large deformation capacity as hyperelastic membranes are gaining prominence in several engineering branches and have applications in biomechanics, thus the study of the dynamic behavior of hyperelastic structures is very important to minimize effects as the loss of the stability and undesirable vibrations. In this paper the elasticity theory for large deformations in the development of membrane theory, in order to investigate the linear and nonlinear dynamic behavior of hyperelastic membrane is used. A rectangular membrane composed of an elastomeric material, isotropic, homogeneous, incompressible and consisting of neo-Hookeano, Mooney-Rivlin and Yeoh models is considered. To model the membrane, the energy and work of external forces are used together with the application of the Hamilton on the Lagrange function. The Galerkin method is applied to obtain a discretized system of nonlinear Partial Differential Equations (PDE) and the Runge-Kutta method of 4th order is used to obtain its time response. Finally, the Brute Force and Continuation methods are applied to investigate the nonlinear dynamic behavior of the membrane. A parametric analysis is carried out looking to evaluate the influence of the material, geometry and initial tensions on the natural frequencies of the membrane. It is noted that increasing the size of a tensioned membrane, it is also increased the natural frequency for a given amplitude, and increasing the strength of a pre-tensioned membrane, the smaller the value of the frequency in relation to a range. Small differences are perceived in the behavior of the membrane for the three constitutive models of material, which are calibrated to represent the same material. Moreover, the main bifurcations of the analyzed membranes are of cyclic bending type, known as saddle-node bifurcation.
Elementos estruturais com grande capacidade de deformação como membranas hiperelásticas vêm ganhando destaque em diversas áreas da engenharia e têm várias aplicações na biomecânica, assim, o estudo do comportamento dinâmico de estruturas hiperelásticas é de grande importância visando minimizar os efeitos, como à perda de estabilidade e vibrações indesejáveis. No presente trabalho é utilizada a teoria da elasticidade para grandes deformações no desenvolvimento da teoria de membranas com o objetivo de investigar o comportamento dinâmico linear e não linear de membranas hiperelásticas. Considera-se a membrana retangular composta por um material elastomérico, isotrópico, homogêneo, incompressível e descrito pelos modelos constitutivos de neo-Hookeano, Mooney-Rivlin e Yeoh. Para obter as equações de equilíbrio estático e dinâmico da estrutura são utilizadas as energias e trabalhos atuantes, bem como o princípio de Hamilton aplicado na função de Lagrange. O Método de Galerkin é utilizado para discretizar as Equações Diferenciais Parciais (EDP) em um sistema de Equações Diferenciais Ordinárias (EDO). Para resolver esse sistema, utiliza-se o Método de Runge-Kutta de quarta ordem e utiliza-se o Método da Força Bruta e o Método da Continuação para investigar o comportamento dinâmico da membrana. É realizada uma análise paramétrica visando avaliar a influência do material e da geometria da membrana nas frequências naturais e nas tensões inicias. Constata-se que as bifurcações das membranas analisadas são do tipo Dobra Cíclica, conhecida como Nó-Sela. Além de verificar que quanto menor o nível de tração, maior será a não linearidade da curva de frequênciaamplitude da membrana e que há leves divergências no comportamento da membrana em relação aos três modelos constitutivos do material adotados.
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Uhrig, Matthias Pascal. "Numerical simulation of nonlinear Rayleigh wave beams evaluating diffraction, attenuation and reflection effects in non-contact measurements". Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54368.
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Although several studies have proven the accuracy of using a non-contact, air-coupled receiver in nonlinear ultrasonic (NLU) Rayleigh wave measurements, inconsistent results have been observed when working with narrow specimens. The objectives of this research are first, to develop a 3D numerical finite element (FE) model which predicts nonlinear ultrasonic measurements and second, to apply the validated model on the narrow waveguide to determine causes of the previously observed experimental issues. The commercial FE-solver ABAQUS is used to perform these simulations. Constitutive law and excitation source properties are adjusted to match experiments conducted, considering inherent effects of the non-contact detection, such as frequency dependent pressure wave attenuation and signal averaging. Comparison of “infinite” and narrow width simulations outlines various influences which impair the nonlinear Rayleigh wave measurements. When the wave expansion is restricted, amplitudes of the fundamental and second harmonic components decrease more significantly and the Rayleigh wavefronts show an oscillating interaction with the boundary. Because of the air-coupled receiver’s finite width, it is sensitive to these edge effects which alter the observed signal. Thus, the narrow specimen adversely affects key factors needed for consistent measurement of material nonlinearity with an air-coupled, non-contact receiver.
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Salisbury, Christopher. "On the Deformation Mechanics of Hyperelastic Porous Materials". Thesis, 2011. http://hdl.handle.net/10012/5858.
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The understanding of the deformation mechanics within porous structures is an important field of study as these materials exist in nature as well as can be manufactured industrially influencing our lives daily. The motivation of the research contained within this manuscript was inspired by the desire to understand the mechanics of an elastomeric closed–cell porous material. This type of porous material is often used in load–bearing applications such as sport helmet liners and packing material which can be subjected to large deformations at high rates. Additionally, short term transient effects were explored.
In order to investigate the deformation mechanics of a closed cell elastomeric foam, a polychloroprene (neoprene) material was chosen as it was available in both rubber form and a foam with relatively consistent cell size. Compression tests were conducted on the polychloroprene rubber at strain rates ranging from 0.001/s to 2700/s which identified that it had a hyper–viscoelastic behaviour with a significant strain rate dependence. A newly developed constitutive model was created to capture the response of the polychloroprene rubber.
A coupled finite element model of the polychloroprene foam was created and compared to experimental tests for validation. The model slightly over predicted the stress level response of the experimental tests. The model was used to identify momentum dissipation mechanisms that contributed to the low wave speed measurement of approximately 70 m/s determined from the model. The investigation of wave transit times through use of the model was key to interpreting experimental data. Of the morphological factors investigated, it was determined that wall thickness had the most significant impact on the stress response of the foam. The pore–scale model was useful for visualizing wavepropagation effects and deformation mechanics which was not feasible experimentally.
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Burela, Ramesh Gupta. "Asymptotically Correct Dimensional Reduction of Nonlinear Material Models". Thesis, 2011. http://etd.iisc.ernet.in/2005/3909.
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This work aims at dimensional reduction of nonlinear material models in an asymptotically accurate manner. The three-dimensional(3-D) nonlinear material models considered include isotropic, orthotropic and dielectric compressible hyperelastic material models. Hyperelastic materials have potential applications in space-based inflatable structures, pneumatic membranes, replacements for soft biological tissues, prosthetic devices, compliant robots, high-altitude airships and artificial blood pumps, to name a few. Such structures have special engineering properties like high strength-to-mass ratio, low deflated volume and low inflated density. The majority of these applications imply a thin shell form-factor, rendering the problem geometrically nonlinear as well. Despite their superior engineering properties and potential uses, there are no proper analysis tools available to analyze these structures accurately yet efficiently. The development of a unified analytical model for both material and geometric nonlinearities encounters mathematical difficulties in the theory but its results have considerable scope. Therefore, a novel tool is needed to dimensionally reduce these nonlinear material models.
In this thesis, Prof. Berdichevsky’s Variational Asymptotic Method(VAM) has been applied rigorously to alleviate the difficulties faced in modeling thin shell structures(made of such nonlinear materials for the first time in the history of VAM) which inherently exhibit geometric small parameters(such as the ratio of thickness to shortest wavelength of the deformation along the shell reference surface) and physical small parameters(such as moderate strains in certain applications).
Saint Venant-Kirchhoff and neo-Hookean 3-D strain energy functions are considered for isotropic hyperelastic material modeling. Further, these two material models are augmented with electromechanical coupling term through Maxwell stress tensor for dielectric hyperelastic material modeling. A polyconvex 3-D strain energy function is used for the orthotropic hyperelastic model. Upon the application of VAM, in each of the above cases, the original 3-D nonlinear electroelastic problem splits into a nonlinear one-dimensional (1-D) through-the-thickness analysis and a nonlinear two-dimensional(2-D) shell analysis. This greatly reduces the computational cost compared to a full 3-D analysis. Through-the-thickness analysis provides a 2-D nonlinear constitutive law for the shell equations and a set of recovery relations that expresses the 3-D field variables (displacements, strains and stresses) through thethicknessintermsof2-D shell variables calculated in the shell analysis (2-D).
Analytical expressions (asymptotically accurate) are derived for stiffness, strains, stresses and 3-D warping field for all three material types. Consistent with the three types of 2-D nonlinear constitutive laws,2-D shell theories and corresponding finite element programs have been developed.
Validation of present theory is carried out with a few standard test cases for isotropic hyperelastic material model. For two additional test cases, 3-Dfinite element analysis results for isotropic hyperelastic material model are provided as further proofs of the simultaneous accuracy and computational efficiency of the current asymptotically-correct dimensionally-reduced approach. Application of the dimensionally-reduced dielectric hyperelastic material model is demonstrated through the actuation of a clamped membrane subjected to an electric field. Finally, the through-the-thickness and shell analysis procedures are outlined for the orthotropic nonlinear material model.
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Khare, Siddharth M. "Micro-Newton Force Measurement and Actuation : Applied to Genetic Model Organisms". Thesis, 2016. http://etd.iisc.ernet.in/2005/3811.
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Mechanical forces have been observed to affect various aspects of life, for example, cell differentiation, cell migration, locomotion and behavior of multicellular organisms etc. Such forces are generated either by external entities such as mechanical touch, fluid flow, electric and magnetic fields or by the living organisms themselves. Study of forces sensed and applied by living organisms is important to understand the interactions between organisms and their environment. Such studies may reveal molecular mechanisms involved in mechanosensation and locomotion.
Several techniques have been successfully applied to measure forces exerted by single cells and cell monolayers. The earliest technique made use of functionalized soft surfaces and membranes as substrates on which cell monolayers were grown. The forces exerted by the cells could be measured by observing deformation of the substrates. Atomic Force Microscope (AFM) is another sensitive instrument that allows one to exert and measure forces in pico-Newton range. Advances in micromachining technology have enabled development of miniature force sensors and actuators. Latest techniques for mechanical force application and measurement use micromachined Silicon cantilevers in single as well as array form and micropillar arrays. Micropillar arrays fabricated using soft lithography enabled the use of biocompatible materials for force sensors. Together, these techniques provide access to a wide range of forces, from sub micro-Newton to milli-Newton.
In the present work, types of forces experienced in biological systems and various force measurement and actuation techniques will be introduced. This will be followed by in depth description of the two major contributions of this thesis,
1) ―Colored polydimethylsiloxane micropillar arrays for high throughput measurements of forces applied by genetic model organisms‖. Biomicrofluidics, January 29, 2015. doi: 10.1063/1.4906905
2) ―Air microjet system for non-contact force application and the actuation of micro-structures‖. Journal of micromechanics and microengineering, December 15, 2015. doi: 10.1088/0960-1317/26/1/017001
Device developed for force measurement consists of an array of micropillars made of a biocompatible polymer Poly Dimethyl Siloxane (PDMS). Such devices have been used by researchers to measure traction forces exerted by single cells and also by nematode worm Caenorhabditis elegans (C. elegans). C. elegans is allowed to move in between the micropillars and the locomotion is video recorded. Deflection of the micropillar tips as the worm moves is converted into force exerted. Transparent appearance of C. elegans and PDMS poses difficulties in distinguishing micropillars from the worm, thus making it challenging to automate the analysis process. We address this problem by developing a technique to color the micropillars selectively. This enabled us to develop a semi-automated graphical user interface (GUI) for high throughput data extraction and analysis, reducing the analysis time for each worm to minutes. Moreover, increased contrast because of the color also delivered better images. Addition of color changed the Young‘s modulus of PDMS. Thus the dye-PDMS composite was characterized using hyper-elastic model. The micropillars were also calibrated using commercial force sensor.
Analysis of forces exerted by wild type and mutant C. elegans moving on an agarose surface was performed. Wild type C. elegans exerted a total average force of 7.68 µN and an average force of ~1 µN on an individual pillar. We show that the middle of C. elegans exerts more force than its extremities. We find that C. elegans mutants with defective body wall muscles apply significantly lower force on individual pillars, while mutants defective in sensing externally applied mechanical forces still apply the same average force per pillar compared to wild type animals. Average forces applied per pillar are independent of the length, diameter, or cuticle stiffness of the animal. It was also observed that the motility of the worms with mechanosensation defects, lower cuticle stiffness, and body wall muscle defects was reduced with worms that have defective body wall muscle having the largest degree. Thus, we conclude that while reduced ability to apply forces affects the locomotion of the worm in the micropillar array, the reduced motility/locomotion may not indicate that the worm has reduced ability to apply forces on the micropillars.
We also used the colored micropillar array for the first time to measure forces exerted by Drosophila larvae. Our device successfully captured the peristaltic rhythm of the body wall muscles of the larva and allowed us to measure the forces applied on each deflected pillar during this motion. Average force exerted by 1st instar wild type Drosophila larvae was measured to be ~ 1.5 µN per pillar.
We demonstrated that a microjet of air can be used to apply forces in micro-Newton range. We developed a standalone system to generate a controlled air microjet. Microjet was generated using a controlled electromagnetic actuation of a diaphragm. With a nozzle diameter of 150 µm, the microjet diameter was maintained to a maximum of 1 mm at a distance of 5 mm from the nozzle. The force generated by the microjet was measured using a commercial force sensor to determine the velocity profile of the jet. Axial flow velocities of up to 25 m/s were obtained at distances as long as 6 mm. The microjet exerted a force up to 1 µN on a poly dimethyl siloxane (PDMS) micropillar (50 µm in diameter, 157 µm in height) and 415 µN on a PDMS membrane (3 mm in diameter, 28 µm thick). We also demonstrate that from a distance of 6 mm our microjet can exert a peak pressure of 187 Pa with a total force of about 84 µN on a flat surface with 8 V operating voltage. Next, we demonstrated that the response of C. elegans worms to the impinging air microjet is similar to the response evoked using a manual gentle touch. This contactless actuation tool avoids contamination and mechanical damage to the samples. Out of the cleanroom fabrication and robust design make this system cost effective and durable.
Magnetic micropillars have been used as actuators. We fabricated magnetic micropillar arrays and designed actuation mechanisms using permanent magnet and a pulsed electromagnet. Force of about 19 µN was achievable using a permanent magnet actuation. In a pulsed electromagnetic field micropillar exerted a force of about 10 µN on a commercial force sensor. These techniques have promising applications when actuation needs to be controlled from long distances.
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Zhao, Ruogang. "The Development and Application of Tools to Study the Multiscale Biomechanics of the Aortic Valve". Thesis, 2012. http://hdl.handle.net/1807/33866.
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Calcific aortic valve disease (CAVD) is one of the most common causes of cardiovascular disease in North America. Mechanical factors have been closely linked to the pathogenesis of CAVD and may contribute to the disease by actively regulating the mechanobiology of valve interstitial cells (VICs). Mechanical forces affect VIC function through interactions between the VIC and the extracellular matrix (ECM). Studies have shown that the transfer of mechanical stimulus during cell-ECM interaction depends on the local material properties at hierarchical length scales encompassing tissue, cell and cytoskeleton.
In this thesis, biomechanical tools were developed and applied to investigate hierarchical cell-ECM interactions, using VICs and valve tissue as a model system. Four topics of critical importance to understanding VIC-ECM interactions were studied: focal biomechanical material properties of aortic valve tissue; viscoelastic properties of VICs; transduction of mechanical deformation from the ECM to the cytoskeletal network; and the impact of altered cell-ECM interactions on VIC survival.
To measure focal valve tissue properties, a micropipette aspiration (MA) method was implemented and validated. It was found that nonlinear elastic properties of the top layer of a multilayered biomaterial can be estimated by MA by using a pipette with a diameter smaller than the top layer thickness. Using this approach, it was shown that the effective stiffness of the fibrosa layer is greater than that of the ventricularis layer in intact aortic valve leaflets (p<0.01). To characterize the viscoelastic properties of VICs, an inverse FE method of single cell MA was developed and compared with the analytical half-space model. It was found that inherent differences in the half-space and FE models of single cell MA yield different cell viscoelastic material parameters. However, under particular experimental conditions, the parameters estimated by the half-space model are statistically indistinguishable from those predicted by the FE model. To study strain transduction from the ECM to cytoskeleton, an improved texture correlation algorithm and a uniaxial tension release device were developed. It was found that substrate strain fully transfers to the cytoskeletal network via focal adhesions in live VICs under large strain tension release. To study the effects of cell-ECM interactions on VIC survival, two mechanical stimulus systems that can simulate the separate effects of cell contraction and cell monolayer detachment were developed. It was found that cell sheet detachment and disrupted cell-ECM signaling is likely responsible for the apoptosis of VICs grown in culture on thin collagen matrices, leading to calcification.
The studies presented in this thesis refine existing biomechanical tools and provide new experimental and analytical tools with which to study cell-ECM interactions. Their application resulted in an improved understanding of hierarchical valve biomechanics, mechanotransduction, and mechanobiology.
Capítulos de libros sobre el tema "Murnaghan hyperelastic material model"
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Wong, Ken C. L., Linwei Wang y Pengcheng Shi. "Active Model with Orthotropic Hyperelastic Material for Cardiac Image Analysis". En Functional Imaging and Modeling of the Heart, 229–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-01932-6_25.
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Łagan, Sylwia y Aneta Liber-Kneć. "The Influence of Stretch Range on the Hyperelastic Material Model Parameters for Pig’s Skin with Consideration of Specimen Taken Direction". En Innovations in Biomedical Engineering, 253–60. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-15472-1_27.
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Limbert, G. y M. Taylor. "An explicit three-dimensional finite element model of an incompressible transversely isotropic hyperelastic material". En Computational Fluid and Solid Mechanics, 319–22. Elsevier, 2001. http://dx.doi.org/10.1016/b978-008043944-0/50640-5.
Texto completoActas de conferencias sobre el tema "Murnaghan hyperelastic material model"
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Jerábek, R. y L. Écsi. "ALTERNATIVE STRAIN-RATE DEPENDENT HYPERELASTIC-PLASTIC MATERIAL MODEL". En Engineering Mechanics 2020. Institute of Thermomechanics of the Czech Academy of Sciences, Prague, 2020. http://dx.doi.org/10.21495/5896-3-242.
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Carbary, Larry D., Jon H. Kimberlain y John C. Oliva. "Hyperelastic Material Model Selection of Structural Silicone Sealants for Use in Finite Element Modeling". En ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-67589.
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Hyperelastic material model parameters have been developed to capture the behavior of silicone based construction sealants. Modern commercially available finite element analysis software makes it quite accessible to develop hyperelastic material models, automating the process of curve-fitting experimental lab data to specific hyperelastic formulations. However, the process of selecting a particular hyperelastic model from those supported is not straightforward. Here, a series of lab experiments are employed to guide the selection of the hyperelastic model that best describes various structural silicone glazings. A total of 10 different sealants are characterized with discussion of variations among the models. Comparisons of the best performing hyperelastic models for the different sealants are presented. Finally, an application is described in which these hyperelastic models have begun to be implemented in practice.
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Luo, Yi, Zhengyi Han, Xianzhang Lei, Mingyu Zhou, Hanyu Ye, Haitian Wang y Yanzhuo Liu. "Techniques for designing prefabricated cable accessories based on hyperelastic material model". En 2018 12th International Conference on the Properties and Applications of Dielectric Materials (ICPADM). IEEE, 2018. http://dx.doi.org/10.1109/icpadm.2018.8401204.
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Homison, Chris y Lisa Mauck Weiland. "Coupled Transport/Hyperelastic Model for High Nastic Materials". En ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-79387.
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Work is underway to develop high energy density active materials based upon biological processes. These materials utilize the controlled transport of charge and fluid across a selectively-permeable membrane to achieve bulk deformation in a process referred to in the plant kingdom as nastic movements. The nastic material being developed consists of synthetic membranes containing biological ion pumps, ion channels, and ion exchangers surrounding fluid-filled cavities embedded within a polymer matrix. In this paper the formulation of a biological transport model and its coupling with a hyperelastic finite element model of the polymer matrix is discussed. The transport model includes contributions from ion pumps, ion exchangers, solvent flux, and ion channels. This work will form the basis for a feedback loop in material synthesis efforts. The goal of these studies is to determine the relative importance of the various parameters associated with both the polymer matrix and the biological transport components.
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Luo, Yun-Mei, Luc Chevalier y Eric Monteiro. "An anisotropic visco-hyperelastic model for PET behavior under ISBM process conditions". En ESAFORM 2016: Proceedings of the 19th International ESAFORM Conference on Material Forming. Author(s), 2016. http://dx.doi.org/10.1063/1.4963407.
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Breslavsky, Ivan, Marco Amabili y Mathias Legrand. "Large Amplitude Vibrations of Thin Hyperelastic Plates: Neo-Hookean Model". En ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62253.
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Static deflection and large amplitude vibrations of a rubber plate are analyzed. Both the geometrical and physical (material) nonlinearities are taken into account. The properties of the plate hyperelastic material are described by the Neo-Hookean law. A method for building a local model, which approximates the plate behavior around a deformed configuration, is proposed. This local model takes the form of a system of ordinary differential equations with quadratic and cubic nonlinearities. The results obtained with the help of this local model are compared to the solution of the exact model, and are found to be accurate. The difference between the model retaining both physical and geometrical non-inearities and a model with only geometrical nonlinearities is also analyzed. It is found that influence of physically induced nonlinearities at moderate strains is significant.
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Pham, Trung, Christopher Hoyle, Yue Zhang y Tam Nguyen. "Topology Optimization of Hyperelastic Continua". En ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-59776.
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Topology optimization (TO) aims to find a material distribution within a reference domain, which optimizes objective function(s) and satisfies certain constraints. Topology optimization has various potential applications in early phases of structural design, e.g., reducing structural weight or maximizing structural stiffness. However, most research on TO has focused on linear elastic materials, which has severely restricted applications of TO to hyperelastic structures made of, e.g., rubber or elastomer. While there is some work in literature on TO of nonlinear continua, to the best knowledge of the authors there is no work which investigates the different models of hyperelastic material. Furthermore, topology optimized designs often possess complex geometries and intermediate densities making it difficult to manufacture such designs using conventional methods. Additive Manufacturing (AM) is capable of handling such complexities. Continuing advances in AM will allow for usage of rubber-like materials, which are modeled by hyperelastic constitutive laws, in producing complex structures designed by TO. The contribution of this paper is an investigation of different models of hyperelastic materials taking account of both geometrical and material nonlinearities, and their influences on the resulting topologies. Topology optimization of nonlinear continua is the main topic of few papers. This paper considers different isotropic hyperelastic models including the Ogden, Arruda–Boyce and Yeoh model under finite deformations, which have not yet been implemented in the context of topology optimization of continua. This paper proposes to start with a reference domain having known boundary and loading conditions. Material parameters of different models that fill the domain are also known. Maximizing the stiffness of the structure subject to a volume constraint is used as the design objective. The domain is then meshed into a large number of finite elements, and each element is assigned a density between 0 and 1, which becomes design variable of the optimization problem. These densities are further penalized to make intermediate densities (i.e., not 0 or 1) less favorable. Optimized material distribution will be constructed from optimized values of design variables. Because of the penalization factors that make the problem nonlinear, the Method of Moving Asymptotes (MMA) is utilized to update it iteratively. At each iteration the nonlinear finite element problem is solved using the Finite Element Analysis Program (FEAP), which has been modified to accept penalized densities on element stiffness matrices and internal nodal forces, and a filtering scheme is applied on the sensitivities of objective function to guarantee the existence of solution. The proposed method is tested on several numerical examples. The first two examples are common benchmark models, which are a simply supported beam , and a beam fixed at two ends. Both models are subjected to a concentrated force at midpoints of their edges. The effects of linear and nonlinear material behaviors are compared with regards to resulting designs. The third example is a foremost attempt to reflect on TO in design of airless tire through a simple model, which demonstrates capability of the method in solving real-world design problems.
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Mesa Vargas, Diego Fernando, Agustín Vidal-Lesso y Jorge Arturo Alfaro Ayala. "A Material Model Fitting for Recycled Polyethylene Terephthalate Implemented in the Finite Element Modelling". En ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-88305.
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In this work, samples of the polyethylene terephthalate material were collected, and then tensile tests were conducted according to ASTM D-882. Three lots of samples were proposed, without sun exposure (0 months), three and six months of sun exposure where the bottles were filled with water and inclined at 45° (with respect to the horizontal), to reproduce the working conditions of a solar collector. Five experimental tests were carried out for each batch, obtaining values of force, deformation, displacement and stress. The experimental data obtained from the tests are used to fit a constituent model for the polyethylene terephthalate material, which reproduces the thermo-structural behavior in the virtual field. According to literature and characteristics of the constitutive models, three hyperelastic models were proposed: Yeoh, Mooney Rivlin and polynomial. The objective of the selection of these constitutive models is to model the material under the real thermo-structural conditions but previously a validation was carried out for each of them. Finally, after a virtual modeling process, reaction force values were collected for each constituent model which will be compared with the actual response of the uniaxial test, where maximum errors of 18% were obtained, which immediately ruled out a constituent model, while the other models handled errors of less than 5% until generating an adjustment close to 1%. The best fit was obtained with Mooney Rivlin’s five parameter hyperelastic model for polyethylene terephthalate.[1][2], [3][4]
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O’Connell, Grace D., Heather L. Guerin y Dawn M. Elliott. "An Anisotropic Hyperelastic Model Applied to Nondegenerate and Degenerate Annulus Fibrosus". En ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-192890.
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The intervertebral disc is comprised of complex components that provide the disc with nonlinear, viscoelastic and anisotropic mechanical properties. The annulus fibrosus (AF) is a highly organized structure composed of concentric layers of collagen fibers embedded in a proteoglycan matrix. The AF has a high tensile stiffness and supports the large loads encountered by the disc. Mathematical models are needed to interpret and elucidate the meaning of experimental measurements made in mechanical tests. Based upon the classic work of Spencer [1], the AF has been modeled as a fiber-induced anisotropic hyperelastic material [e.g.,2–6], using the principle invariants of the Green deformation tensor and structural tensors representing the collagen fiber populations. Contributions of other AF components to mechanical behaviors are less understood than the fibers or matrix and may include connections between collagens and proteoglycans that can be incorporated into models through fiber-matrix interactions [2–4]. The previous models, however, have not been applied to experimental data from both nondegenerate and degenerate tissue. Constitutive modeling applied to nondegenerate and degenerate AF may elucidate microstructural changes with degeneration, will be useful for finite element models [5], and provide targets for disc treatments, such as tissue engineered constructs [7].
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Freeman, Eric y Lisa Weiland. "Parametric Studies of a Coupled Transport/Hyperelastic Model for High Energy Density Nastic Materials". En ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43072.
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The focus of this research is to optimize the performance of a high energy density active material based upon biological processes. This material uses controlled transport of charge and fluid across a selectively permeable membrane to achieve bulk deformation, similar to nastic movements in the plant kingdom. The membrane utilizes biological ion pumps, ion channels, and ion exchangers surrounding a spherical inclusion in a polymer matrix. This work examines the effect of the geometry of the inclusion and the surrounding matrix on the predictions of the model.
Informes sobre el tema "Murnaghan hyperelastic material model"
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Zywicz, E. The Development of DYNA3D Material Model 67 - Hyperelastic Elastomeric Foam With Viscoelasticity. Office of Scientific and Technical Information (OSTI), enero de 2015. http://dx.doi.org/10.2172/1179428.
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