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Dissertations / Theses on the topic 'Viscoelastic waves'

Author: Grafiati

Published: 2 June 2025

Last updated: 31 July 2025

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1

Zhang, Xueyan. "Mechanics of viscoelastic mud under water waves." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36710003.

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Zhang, Xueyan, and 張雪岩. "Mechanics of viscoelastic mud under water waves." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B36710003.

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The Best M.Phil Thesis in the Faculties of Dentistry, Engineering, Medicine and Science (University of Hong Kong), Li Ka Shing Prize,2005-2006<br>published_or_final_version<br>abstract<br>Mechanical Engineering<br>Master<br>Master of Philosophy

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3

Camacho, Victor. "Analyzing Traveling Waves in a Viscoelastic Generalization of Burgers' Equation." Scholarship @ Claremont, 2007. https://scholarship.claremont.edu/hmc_theses/193.

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We analyze a pair of nonlinear PDEs describing viscoelastic fluid flow in one dimension. We give a summary of the physical derivation and nondimensionlize the PDE system. Based on the boundary conditions and parameters, we are able to classify three different categories of traveling wave solutions, consistent with the results in [?]. We extend this work by analyzing the stability of the traveling waves. We thoroughly describe the numerical schemes and software program, VISCO, that were designed specifically to analyze the model we study in this paper. Our simulations lead us to conjecture that

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4

VADALA', FRANCESCA. "Free and forced propagation of Bloch waves in viscoelastic beam lattices." Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/1001821.

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Beam lattice materials can be characterized by a periodic microstructure realizing a geometrically regular pattern of elementary cells. Within this framework, governing the free and forced wave propagation by means of spectral design techniques and/or energy dissipation mechanisms is a major issue of theoretical interest with applications in aerospace, chemical, naval, biomedical engineering. The first part of the Thesis addresses the free propagation of Bloch waves in non-dissipative microstructured cellular materials. Focus is on the alternative formulations suited to describe the wave prop

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5

Ahonsi, Bright. "On the propagation of stress waves in viscoelastic rods for Hopkinson bar studies." Thesis, University of Aberdeen, 2011. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=182239.

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The propagation of stress waves in long polymer rods forms the basis of two major experimental techniques. The first is a modified Split-Hopkinson pressure bar (SHPB) arrangement that employs polymer Hopkinson bars (as opposed to metallic bars) in order to determine the high strain-rate mechanical properties of soft materials. The second experimental technique consists of a group of methods for determining the viscoelastic properties of polymer rods within a frequency range of 20 Hz to 30 kHz. An experimental, analytical and finite element study of stress waves propagating in viscoelastic rods

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6

Copeland, David B. "Measurement of the complex shear modulus and its frequency dependence for viscoelastic materials." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/17517.

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7

Yang, Lixiang. "Modeling Waves in Linear and Nonlinear Solids by First-Order Hyperbolic Differential Equations." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1303846979.

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8

Didier, Pierre. "Développement d’un système à ondes acoustiques pour le suivi rhéologique de la polymérisation de protéines. Application à la maladie d’Alzheimer." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLN016/document.

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La mise au point de nouveaux systèmes biocompatibles de suivi des phénomènes de polymérisation de protéines est un enjeu majeur pour la compréhension des mécanismes moléculaires en vue d’une détection et d’un traitement précoce des pathologies dites conformationnelles telles que la maladie d’Alzheimer ou les maladies à prions. Dans ces pathologies, des protéines ou des fragments de celles-ci perdent leur structure, puis s’assemblent en fibres ordonnées au sein d’agrégats. Les mécanismes moléculaires du changement de conformation d'une protéine et sa polymérisation en fibres amyloïdes sont enco

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9

Rasolofosaon, Patrick N. J. "Propagation des ondes acoustiques dans les milieux poreux : effets d'interface, experiences et theorie." Paris 7, 1987. http://www.theses.fr/1987PA077151.

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Une premiere partie theorique expose en detail la propagation des ondes acoustiques dans les milieux poreux a travers le modele poroviscoelastique. On montre que les effets poroelastiques ne sont superieurs aux effets viscoelastiques qui en presence de discontinuites physiques ou d'echange hydraulique entre differents milieux. Trois experiences dans la deuxieme partie, celle de plona, resonance des modes de lamb, propagation d'ondes a l'interface roche fluide. Dans la troisieme partie, on envisage l'inversion des mesures acoustiques

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10

Laksari, Kaveh. "Nonlinear Viscoelastic Wave Propagation in Brain Tissue." Diss., Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/242293.

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Mechanical Engineering<br>Ph.D.<br>A combination of theoretical, numerical, and experimental methods were utilized to determine that shock waves can form in brain tissue from smooth boundary conditions. The conditions that lead to the formation of shock waves were determined. The implication of this finding was that the high gradients of stress and strain that could occur at the shock wave front could contribute to mechanism of brain injury in blast loading conditions. The approach consisted of three major steps. In the first step, a viscoelastic constitutive model of bovine brain tissue under

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11

Vollmann, Johannes. "Wave propagation in viscoelastic and anisotropic, cylindrical structures." Online version, 1996. http://dds.crl.edu/CRLdelivery.asp?tid=11233.

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12

Musa, Abu Bakar. "Wave motion and impact effects in viscoelastic rods." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/10799.

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Two separate problems are to be investigated in this thesis. The first problem is the propagation of waves through a short rod (or slug) of viscoelastic material. The second problem is the study of impact of a short viscoelastic rod (or slug) on a stationary semi-infinite viscoelastic. rod. The viscoelastic materials are modelled as standard linear solids which involve 3 material parameters and the motion is treated. as one-dimensional. For the first study, a viscoelastic slug is placed between two semi-infinite elastic rods and a wave initiated in the first rod is transmitted through the slug

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13

Lindley, Brandon S. Forest M. Gregory. "Linear and nonlinear shear wave propagation in viscoelastic media." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,1650.

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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2008.<br>Title from electronic title page (viewed Sep. 16, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Mathematics." Discipline: Mathematics; Department/School: Mathematics.

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14

Mousavi, Saed. "Identification of Viscoelastic Materials by Use of Wave Propagation Methods." Doctoral thesis, Uppsala universitet, Hållfasthetslära, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8324.

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Complex moduli and Poisson’s ratio have been estimated using extensional and torsional wave experiments. The data were used for assessment of linearity and isotropy of two polymers, polymethyl methacrylate (PMMA) and polypropylene (PP). The responses of both materials were found to be close to linear and isotropic. A statistical analysis of different estimation approaches for complex modulus and Poisson’s ratio was conducted. It was shown that a joint estimation of complex modulus and Poisson’s ratio improves the estimated results. Considerable improvement was achieved in the frequency range 5

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15

Zlatev, Zahari. "Ultrasonic guided wave propagation in pipes coated with viscoelastic materials." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/12753.

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This work studies guided wave propagation in pipes coated with thick highly viscoelastic coating materials. The main motivation for this study is the problems associated with Long Range Ultrasonic Testing (LRUT) of coated pipelines. The results reported in the literature show that the proper determination of the optimum LRUT parameters depends strongly on the bulk acoustic properties of the coating materials. The bulk acoustic properties of coating materials reported in the literature show that they could vary significantly depending on the coating material age, temperature and bonding level.

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16

Rusovici, Razvan. "Modeling of Shock Wave Propagation and Attenuation in Viscoelastic Structures." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/29153.

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Protection from the potentially damaging effects of shock loading is a common design requirement for diverse mechanical structures ranging from shock accelerometers to spacecraft. High-damping viscoelastic materials are employed in the design of geometrically complex impact absorbent components. Since shock transients have a broadband frequency spectrum, it is imperative to properly model frequency dependence of material parameters. The Anelastic Displacement Fields (ADF) method is employed to develop new axisymmetric and plane stress finite elements that are capable of modeling frequency depe

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17

Schanz, Martin. "Wave propagation in viscoelastic and poroelastic continua : a boundary element approach /." Berlin [u.a.] : Springer, 2001. http://www.loc.gov/catdir/enhancements/fy0816/2001020508-d.html.

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18

Rensfelt, Agnes. "Viscoelastic Materials : Identification and Experiment Design." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-111283.

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19

Salisbury, Christopher. "Spectral Analysis of Wave Propagation Through a Polymeric Hopkinson Bar." Thesis, University of Waterloo, 2001. http://hdl.handle.net/10012/799.

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The importance of understanding non-metallic material behaviour at high strain rates is becoming ever more important as new materials are being developed and used in shock loading applications. Applying conventional methods for high strain rate testing to non-metallic materials proved ineffective due to impedance mismatch between the specimen and apparatus and so a new test method was developed. A polymeric Hopkinson bar was developed enabling non-metallic materials, such as polycarbonate and rubber, to be tested at strain rates from 500 s^-1 to 4000 s^-1. Conventional Hopkinson bar a

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20

Hernando, Quintanilla Francisco. "Pseudospectral collocation method for viscoelastic guided wave problems in generally anisotropic media." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/34915.

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In Non-Destructive Evaluation (NDE) applications guided waves are attractive to perform rapid inspections of long lengths and large areas. However, they are complicated, therefore it is important to have as much information and understanding about their physical properties as possible in order to design the most efficient and robust inspection process as well as to draw the correct conclusions from the measurement results. The main piece of information to gain insight into the guided wave's properties is dispersion curves which, for isotropic structures such as plates and cylinders, have been

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21

Hayner, Mark A. (Mark Andrew). "Optimized finite difference schemes for wave propagation in high loss viscoelastic material." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/36488.

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22

Searle, Toby William. "Purely elastic shear flow instabilities : linear stability, coherent states and direct numerical simulations." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28991.

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Recently, a new kind of turbulence has been discovered in the flow of concentrated polymer melts and solutions. These flows, known as purely elastic flows, become unstable when the elastic forces are stronger than the viscous forces. This contrasts with Newtonian turbulence, a more familiar regime where the fluid inertia dominates. While there is little understanding of purely elastic turbulence, there is a well-established dynamical systems approach to the transition from laminar flow to Newtonian turbulence. In this project, I apply this approach to purely elastic flows. Laminar flows are ch

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23

Lin, Po-Hsien. "Solving First-Order Hyperbolic Problems For Wave Motion in Nearly Incompressible fluids, Two-Phase Fluids, and Viscoelastic Media By the CESE Method." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1420552163.

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24

Heitz, Jean-François. "Propagation d'ondes en milieu non linéaire : applications à la reconnaissance des sols et au génie parasismique." Grenoble 1, 1992. http://www.theses.fr/1992GRE10120.

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La propagation d'ondes en milieu non lineaire est etudiee sur les plans theorique, experimental et numerique. Des applications touchant les domaines du genie parasismique et de la reconnaissance in situ des sols sont proposes. Apres un etat des connaissances acquises a ce jour sur le comportement du sol sous sollicitation dynamique, un modele de comportement viscoelastique non lineaire est introduit dans l'equation fondamentale de la dynamique. L'equation du mouvement du sol obtenue exhibe au second membre un terme de source contenant l'ensemble des termes caracteristiques lies a la non-linear

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25

Huertas, Paulo Nicanor Seminario. "Atratores globais para uma equação viscoelástica não linear com história." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/55/55135/tde-14102016-143012/.

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Neste trabalho estudamos uma classe de equações de ondas da forma ∣∂tu∣p ∂ ttu - Δ∂ttu - αu + ∫∞0µ(s)Δu(t - s)ds +F(u) = h, definida num domínio limitado de R3, com condição de fronteira de Dirichlet e parâmetros α, ρ >0. Tais equações modelam problemas de viscoelasticidade não linear e têm sido estudados por diversos autores. Aqui, apresentamos um teorema de existência, unicidade e dependência contínua em relação aos dados iniciais, para soluções fracas, como discutido por Conti, Marchini & Pata (2014). Em seguida pr

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26

Santarelli, Roberta. "Helium-3 Magnetic Resonance Elastography of the lung." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112026/document.

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Selon l'American Lung Association, dans les dernières années, les maladies pulmonaires sont devenues la troisième cause mondiale de décès après les maladies cardiovasculaires et le cancer. Et il est prévu que la position augmente dans ce classement au cours des dix prochaines années. Les maladies pulmonaires telles que la broncho-pneumopathie chronique obstructive (BPCO) et la fibrose interstitielle affectent des millions de personnes dans le monde, tuant des milliers d'entre eux chaque année tandis que de nouveaux cas sont signalés. Aujourd'hui, il n'y a pas de diagnostic précoce des maladies

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27

Morais, Vinicius Souza [UNESP]. "Previsão de ondas geradas por ventos em águas interiores e sua alteração devido à presença de vegetação aquática em margens de lagos." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/88866.

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Made available in DSpace on 2014-06-11T19:23:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-11Bitstream added on 2014-06-13T20:50:43Z : No. of bitstreams: 1 morais_vs_me_ilha.pdf: 9848157 bytes, checksum: 187eadcaad3e9775d2aa107935283406 (MD5)<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>Este trabalho dá continuidade e aperfeiçoa um modelo automatizado para estimativa de altura de ondas geradas em lagos de barragens, a partir dos dados característicos de vento. Infere sobre a climatologia dos ventos, a fim de determinar as maiores alturas de ondas e ident

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28

Azzez, Khouloud. "Caractérisation et modélisation du comportement mécanique in vivo de la peau." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEE004.

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La caractérisation du comportement mécanique du tissu cutané s'avère d'une importance primordiale pour plusieurs domaines à savoir la dermatologie, la cosmétologie, etc. Cette étude du comportement mécanique de la peau soulève toujours des problématiques d'actualité vu la complexité de ce matériau et l'évolution accrue des techniques utilisées. D'où la nécessité du développement d'outils spécifiques pour la caractérisation de la peau humaine. Le travail de cette thèse associe expérimentations et modélisations et il a pour but d'identifier les propriétés mécaniques de la peau humaine in vivo. I

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29

Morais, Vinicius Souza. "Previsão de ondas geradas por ventos em águas interiores e sua alteração devido à presença de vegetação aquática em margens de lagos /." Ilha Solteira : [s.n.], 2009. http://hdl.handle.net/11449/88866.

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Orientador: Geraldo de Freitas Maciel<br>Banca: Carlos Roberto Minussi<br>Banca: Luiz Edival Souza<br>Resumo: Este trabalho dá continuidade e aperfeiçoa um modelo automatizado para estimativa de altura de ondas geradas em lagos de barragens, a partir dos dados característicos de vento. Infere sobre a climatologia dos ventos, a fim de determinar as maiores alturas de ondas e identificar pontos críticos, tanto para a segurança à navegação, quanto para as margens do reservatório. Lagos de barragens, foco desta dissertação são, em sua maioria, dotados de vegetação aquática. Dentro dessa temática,

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30

Saade, Christelle. "Méthodes isogéométriques espace-temps pour des équations multi-champs en mécanique." Thesis, Ecole centrale de Marseille, 2020. http://www.theses.fr/2020ECDM0011.

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Dans ce travail, nous introduisons différentes formulations faibles basées sur des méthodes de Galerkin continues en temps pour plusieurs types de problèmes, pilotés par des équations aux dérivées partielles dans l’espace et le temps. Notre approche repose sur une discrétisation simultanée et arbitraire de l’espace et du temps. L’analyse isogéométrique (IGA) est utilisée comme outil de discrétisation à la place de la méthode classique des éléments finis (FEM) afin de bénéficier des propriétés de continuité des fonctions B-splines et NURBS. Un état de l’art détaillé est présenté pour introduire

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31

Yotte, Sylvie. "Contribution a l'analyse theorique et experimentale du comportement d'un massif sous l'effet de sollicitations liees au foncage et au vibrofoncage." Nantes, 1988. http://www.theses.fr/1988NANT2025.

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Simulation du vibrofoncage d'un pieu dans un massif sableux, assimile a un demi-espace viscoelastique, par une methode semi-analytique, en decomposant le pieu en sources reparties; resolution, a partir des equations de propagation d'ondes, par la transformee de hankel, permettant d'etablir en un point les deplacements dus aux ondes de volume et de rayleigh. Etude experimentale sur un modele plan (modele de schneebeli) et sur un modele reduit fonce en cuve

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32

Pareige, Pascal. "Spectroscopie des résonances acoustiques : source interne dans les tubes, inclusions cylindriques liquides." Le Havre, 1988. http://www.theses.fr/1988LEHAA001.

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Diffusion par une coque élastique remplie d'air et immergée dans l'eau. L'examen des spectres de résonances porte sur les résonances associées aux ondes de Scholte-Stoneley et de la première onde de galerie à écho. Diffusion par des cavités situées dans de l'aluminium et contenant un liquide. On montre que l'écart en fréquence réduite séparant deux résonances consécutives est constant et égal à pi /2

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33

Tardieu, Marion. "Élastographie par résonance magnétique et onde de pression guidée." Phd thesis, Université Paris Sud - Paris XI, 2014. http://tel.archives-ouvertes.fr/tel-01059105.

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Les propriétés mécaniques des tissus biologiques sont des paramètres importants en médecine : ce sont des biomarqueurs du fonctionnement normal ou pathologique d'un tissu. En effet, ces propriétés peuvent être affectées par certaines conditions mécaniques telles que l'application d'une contrainte externe, comme l'hypertension ou un traumatisme, mais également par la présence de certaines maladies, telles que le cancer, la fibrose, l'inflammation, la maladie d'Alzheimer, ou bien tout simplement avec l'âge. La palpation réalisée par le médecin permet de discerner ces changements mais ce geste es

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34

Luo, Wei. "Ultrasonic guided waves and wave scattering in viscoelastic coated hollow cylinders." 2005. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-1160/index.html.

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35

Giannoula, Alexia. "Propagation of Shear Waves Generated by a Finite-amplitude Ultrasound Radiation Force in a Viscoelastic Medium." Thesis, 2008. http://hdl.handle.net/1807/11207.

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A primary purpose of elasticity imaging, commonly known as elastography, is to extract the viscoelastic properties of a medium (including soft tissue) from the displacement caused by a stress field. Dynamic elastography methods that use the acoustic radiation force of ultrasound have several advantages, such as, non-invasiveness, low cost, and ability to produce a highly localized force field. A method for remotely generating localized low frequency shear waves in soft tissue is investigated, by using the modulated radiation force resulting from two intersecting quasi-CW confocal ultrasound b

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36

Kuo, Chi-Wei 1982. "Guided Wave Propagation in Tubular Section with Multi-Layered Viscoelastic Coating." Thesis, 2012. http://hdl.handle.net/1969.1/148398.

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Three kinds of propagating waves physically admissible in a tubular section are derived to establish their dispersion characteristics in response to the presence of multi-layered viscoelastic coatings. One is the longitudinal wave that propagates in the axial direction. The other two are shear and longitudinal waves along the circumferential direction. To characterize the hollow cylinder with coating layers, wave dispersion and attenuation are studied using the “global matrix” technique. Since each layer is considered to be perfectly bonded to each other, displacement and strain continuity

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37

Mu, Jing Rose Joseph L. "Guided wave propagation and focusing in viscoelastic multilayered hollow cylinders." 2008. http://etda.libraries.psu.edu/theses/approved/PSUonlyIndex/ETD-2895/index.html.

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38

Montagnon, Emmanuel. "Modélisation de la diffraction des ondes de cisaillement en élastographie dynamique ultrasonore." Thèse, 2013. http://hdl.handle.net/1866/10977.

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L'élastographie ultrasonore est une technique d'imagerie émergente destinée à cartographier les paramètres mécaniques des tissus biologiques, permettant ainsi d’obtenir des informations diagnostiques additionnelles pertinentes. La méthode peut ainsi être perçue comme une extension quantitative et objective de l'examen palpatoire. Diverses techniques élastographiques ont ainsi été proposées pour l'étude d'organes tels que le foie, le sein et la prostate et. L'ensemble des méthodes proposées ont en commun une succession de trois étapes bien définies: l'excitation mécanique (statique ou dynamique

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Domingues, Luís Évora. "Drug delivery assisted by ultrasound in viscoelastic materials." Master's thesis, 2022. http://hdl.handle.net/10316/99380.

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Dissertação de Mestrado em Matemática apresentada à Faculdade de Ciências e Tecnologia<br>The main goal of this work is the analytical and numerical study of a differential system defined by an integro-differential equation of hyperbolic type and a convection-diffusion-reaction equation. This system arises in the mathematical modeling of drug delivery enhanced by ultrasound. In this case, the hyperbolic equation describes the target displacement generated by ultrasound and the second equation describes the drug transport. The parabolic equation depends on the displacement and eventually on its

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40

Hsiao, Yi-Cheng, and 蕭易承. "Study of the energy transmission and wave propagation of a viscoelastic thick tube conveying fluid." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/bxjz23.

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碩士<br>崑山科技大學<br>機械工程研究所<br>96<br>A mathematical model closer to the artery is proposed to describe the pressure wave propagating in the artery. We treat the wall as a elastic wall and thick walled cylindrical shell and the fluid as an incompressible and laminar. The muscle is simulated by elastic foundation and put into the wall of managing having a viscid condition and the motion of fluid by the linear momentum equation and the continuity equation, and therefore, the governing equations are derived. We consider the propagation of harmonic waves in the governing equations. In that way, we can

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Chen, Pei-Yu, and 陳培煜. "Development of a High Frequency Shear Wave Technique for Detecting the Viscoelastic Properties of Thrombus." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/78930642320661420622.

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碩士<br>輔仁大學<br>電機工程學系碩士班<br>102<br>Measurements of the viscoelastic properties of a thrombus can be used to assess whether blood clots are likely to become occlusive or to break apart and leak into the blood circulation and block smaller vessels. An accurate method for estimating both the shear elasticity and viscosity of a blood clot in vivo is still lacking, which prompted us to use a novel shear-wave approach to measure the viscoelastic modulus of blood clots. The frequency dispersion of the shear-wave propagation speed in soft tissue was used to measure both the elasticity and viscosity of

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Дзюба, Лідія Федорівна. "Поперечні коливання в’язкопружних поздовжньо-рухомих гнучких елементів". Thesis, 2016. http://hdl.handle.net/123456789/2139.

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Abstract:

In this article bending oscillations of moving belt drive, which is described by differential equations are investigated. They contain mixed derivative in time and space coordinates. The nonlinearity of the material mechanical properties is concidered. It was described by Kelvin - Voigt viscoelastic model. Taking into account the finite length of flexible element is made assumptions about the influence of nonlinear force on laws of change over time amplitude and frequency of the bending vibrations. Therefore, the differential equation considered to be weakly nonlinear. The solution of differe

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