45 research outputs found
Analyse par la méthode des éléments finis du comportement en rupture du ciment de l'implant femoral
La tenue mĂ©canique de la prothĂšse totale de hanche dĂ©pend essentiellement de la nature du ciment utilisĂ©. Le rĂŽle principal du ciment est d'assurer une bonne adhĂ©sion implantâos et de minimiser le transfert de charge de l'implant Ă l'os. Sous l'effet des sollicitations mĂ©caniques, le ciment doit pouvoir rĂ©sister Ă l'initiation et Ă la propagation de fissure pouvant conduire Ă sa ruine et par consĂ©quent au descellement de la prothĂšse. Notre travail s'inscrit dans ce contexte et a pour objectif l'analyse par la mĂ©thode des Ă©lĂ©ments finis du comportement en rupture du ciment fixant l'implant Ă l'os. Le champ de cette analyse s'Ă©tend sur diffĂ©rentes zones du ciment (proximale, mĂ©diane et distale) des cĂŽtĂ©s extĂ©rieur et intĂ©rieur du fĂ©mur. Nous montrons clairement l'effet de la position et de l'orientation de la fissure dans le ciment sur les variations du facteur d'intensitĂ© de contrainte en pointe de fissure
Inverse spectral problems for energy-dependent Sturm-Liouville equations
We study the inverse spectral problem of reconstructing energy-dependent
Sturm-Liouville equations from their Dirichlet spectra and sequences of the
norming constants. For the class of problems under consideration, we give a
complete description of the corresponding spectral data, suggest a
reconstruction algorithm, and establish uniqueness of reconstruction. The
approach is based on connection between spectral problems for energy-dependent
Sturm-Liouville equations and for Dirac operators of special form.Comment: AMS-LaTeX, 28 page
Finite element analysis of the behaviour of a crack in the orthopedic cement
In this paper, the finite element method is used to analyse the crack behaviour in the
orthopedic cement of the total hip replacement by computing the stress intensity factors
(SIFs) arround the crack tip. In this work, three cases are studied: crack emanating from
a cavity, interaction effect of the crack emanating from a cavity with another cavity and
the interaction effect of two cracks emanatingfrom two cavities. The stress intensity factors
under mixed mode problems at the crack tip are computed for three zones of prosthesis:
proximal, median and distal. The obtained results show that the crack initiated from a
micro-cavity in the distal zone of cement can be propagated at the same time by opening
and shearing of its lips. It is contrary to that initiated in the proximal zone which cannot
be propagated. The mechanical behaviour of cracks in the medial zone depends of the crack
initiation position
Analysis of Thermal Residual Stresses Distribution in Circular and Elliptical Bonded Composite Repair of Metallic Cracked Structures
Stress intensity factor for repaired crack with bonded composite patch under thermo-mechanical loading
International audienc
3D FE analysis of the behavior of elliptical cracks on orthopedic cement of the total hip prosthesis
An explicit analysis conducted on the crack behavior in chirurgical cement (Polymethylmethacrylate â PMMA) used for Total Hip Prosthesis (THP) is of great importance in collecting information about the nature of the phenomenon of loosening of the cement application. The rupture of the orthopedic cement is practically the main cause of this loosening. Understanding diïŹerent rupture mechanisms give a great value in advancing the durability of the cemented total prosthesis. The purpose of this study is to analyse cracks behavior, initiated in the cement that links the femoral-stem with the bone, using the Finite Element Analysis Method (FEM). The present study brings into focus the variation of the stress intensity factor in modes I, II and III. This rupture criterion is used according to the nature of crack, its orientation and its location in the orthopedic cement. At ïŹrst, the level and distribution of the equivalent von Mises stress is analysed, which is induced in the medial, proximal and distal parts of the bone cement. Then, the behavior of diïŹerent geometric forms of an elliptical crack is evaluated which are located and initiated within the body of these three parts
Analyse par la MEF du comportement de fissures émanant de microcavités dans le ciment orthopédique de fixation d'une PTH
Polymethylmethacrylate (PMMA) est un ciment orthopédique utilisé pour fixer plusieurs implants orthopédiques. la rupture du ciment orthopédique provoque le descellement des implants sous l'effet des chargements cyclique de la marche dans cette étude. La méthode des éléments finis bidimensionnelle est utilisée pour analyser le comportement d'une fissure émanent d'une microcavité et une fissure ordinaire à l'intérieur du ciment orthopédique par le calcule des facteurs d'intensité de contrainte à la pointe de fissure. Trois types de chargements son analysé. Nous avons remarqué qu'il y a un risque de propagation de fissure dans la direction radial de la jonction cupule-ciment. L'étude comparative montre clairement que la fissure émanent de la microcavité est la plus dangereuse. La différence du facteur d'intensité de contrainte entre les deux fissures varie quand la direction des deux fissures change et elle reste constante quand on change le mode de chargement