scholarly journals Computer and experimental analyses of the stress state in the cement hip joint endoprosthesis body

2014 ◽  
Vol 71 (11) ◽  
pp. 1034-1039
Author(s):  
Slobodan Tabakovic ◽  
Jovan Grujic ◽  
Milan Zeljkovic ◽  
Zoran Blagojevic ◽  
Bojan Radojevic ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress State ◽  
Hip Joint ◽  
Biomechanical Analysis ◽  
Critical Cross Section ◽  
The Finite Element Method ◽  
Hip Joint Endoprosthesis ◽  
Custom Made ◽  
Element Method

Background/Aim. One of the possible complications after implantation of a cement hip-joint endoprosthesis is fracture in the endoprosthesis body. Fractures arise from overload or material fatigue of which an implant is made. The purpose of this research was to define the intensity of maximum stress and the positions of a critical cross-section in the endoprosthesis body. Methods. Unilaterally changing forces which act on the hip joint during walking as well as the loads result in flexible deformations of the endoprosthesis body. Biomechanical analysis of the forces acting on the hip joint determine their direction and intensity, whereas on the basis of Gruen?s classification of the endoprosthesis body loosening the level of fixation is established. The bodies of cement hip joint endoprosthesis are made of cobalt-chromiummolybdenum (CoCrMo) alloy, suitable for vacuum casting, are submitted to the analysis. Analysis of the critical stress in the endoprosthesis body was performed on the endoprosthesis body by means of the finite element method. The experimental verification of the obtained results was carried out on the physical prototype under laboratory conditions. Results. Computer analysis, by means of the finite element method, determined the stress state by calculation of the maximum Von Mises stress and critical cross-sections for different angles of the resultant force action. The results obtained by the computer and experimental method correlate and are comparable to the results of similar analyses conducted on various endoprosthesis types. Conclusion. The analyses described in the paper make the basis for improving the process designing of hip joint endoprostheses and their customization to each individual patient (custom made).

scholarly journals УЗАГАЛЬНЕННЯ МОДЕЛІ ФОЛЬКЕРСЕНА НА ВИПАДОК ОСЬОВОЇ СИМЕТРІЇ

2021 ◽  
pp. 78-89
Author(s):  
К. П. Барахов
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Stress State ◽  
Boundary Conditions ◽  
Classical Model ◽  
The Finite Element Method ◽  
Premature Failure ◽  
One Dimensional ◽  
Element Method

Thin-walled structures may contain defects as cracks and holes that are leftovers of the material the construction, is made of or they occur during the operation as a result of, for example, mechanical damage. The presence of holes in the plate causes a concentration of stresses at the boundary of the holes and ultimately leads to premature failure of the structural element. Repair of local damage of modern aircraft structures can be made by creating overlays that are glued to the main structure. The overlay takes on part of the load, unloading the damaged area. This method of repair provides tightness and aerodynamic efficiency to the structure. The calculation of the stress state of such glued structures is usually performed by using the finite element method. The classic models of the stress state of overlapped joints are one-dimensional. That is, the change of the stress state along only one coordinate is considered. At the same time, the connections of a rectangular form are also considered. The purpose of this work is to create a mathematical model of the stress state of circular axisymmetric adhesive joints and to build an appropriate analytical solution to the problem. It is assumed that the bending of the plates is absent; the deformation of the plates is even by thickness. The adhesive layer works only on the shift. The main plate and the overlay are considered isotropic. The solution is built on polar coordinates. The stress state of the connection depends only on the radial coordinate, i.e. one-dimensional. The solution is obtained in analytical form. This mathematical model is a generalization of the classical model of the adhesive connection of Volkersen to a circular or annular region and is considered for the first time. Boundary conditions are met exactly. The satisfaction of marginal conditions, as well as boundary conditions, leads to a system of linear equations with respect to the unknown coefficients of the obtained solutions. The model problem is solved and the numerical results are compared with the results of calculations performed by using the finite element method. It is shown that the proposed model has sufficient accuracy for engineering problems and can be used to solve problems of the design of aerospace structures.

Biomechanical Analysis of Selected Endoprostheses of Hip Joint by Means of Finite Element Methods

2015 ◽  
Vol 226 ◽  
pp. 29-32
Author(s):  
Marcin Basiaga ◽  
Joanna Przondziono
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Boundary Conditions ◽  
Hip Joint ◽  
Biomechanical Analysis ◽  
Geometric Features ◽  
The Finite Element Method ◽  
Hip Joint Endoprosthesis ◽  
Selection Of

The main purpose of this paper was biomechanical analysis of hip joint endoprosthesis – femur systems by means of the Finite Element Method. During the analysis two endoprostheses with differential geometric features were selected. Geometric models of analysed implants were compiled on the grounds of real models like Merotan and The DePuy Proxima which were chosen from series diamensional. Afterwards the models were discretization and boundary conditions were set. Those boundary conditions with right accuracy copied a phenomena which occurred in real models - the Pauwels model. The field of analysis involved determination of the state of displacements, strains and stresses which were cut down in the of endoprosthesis – bone systems. The analysis that was carried out constitute the basics for optimisation of implant geometry and right selection of material’s mechanical properties to its production.

scholarly journals The Action Result of the Concentrated Load on the Briquettes which Obtained from the Technogenous Material

2017 ◽  
Vol 2 (2) ◽  
pp. 97
Author(s):  
Yu.N. Loginov ◽  
N.А. Babailov ◽  
D.N. Pervukhina
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress State ◽  
The Finite Element Method ◽  
Concentrated Load ◽  
Tensile Stresses ◽  
Calculation Results ◽  
Element Method

<p class="TTPAbstract">In this study, the calculation results of the briquette stress state by the Finite element method are presented. The fields of compressive and tensile stresses in briquette are determined. The conditions affecting the process of the briquette destruction are considered.</p>

Analysis the Cable Replacement Method of Tianjin Yonghe Bridge

2011 ◽  
Vol 71-78 ◽  
pp. 1383-1387 ◽  
Author(s):  
Wen Juan Yao ◽  
Wu Yang ◽  
Xiao Yu Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress State ◽  
Main Beam ◽  
The Finite Element Method ◽  
Replacement Method ◽  
Replacement Process ◽  
Before And After ◽  
Element Method

Taking Tianjin Yonghe bridge for example, the finite element method is adopted to simulate each stages of cable replacement process, the dates of tension, the alignment of main beam and the change of stress before and after cable replacement are compared and analysed, The measured value is greatly consistent with calculated value, Stress state of the bridge has been greatly improved, the weight of main beam bearing by the cable will be shared by a few closed cable after unloading, so the cables which are more serious corroded should be replaced.

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