scholarly journals Theoretical and Finite Element Modeling of Fine Kirschner Wires in Ilizarov External Fixator

2010 ◽  
Vol 4 (3) ◽  
Author(s):  
A. R. Zamani ◽  
S. O. Oyadiji
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Kirschner Wires ◽  
Fe Method ◽  
Mathematical Solution ◽  
New Exact Solutions ◽  
Ilizarov Apparatus ◽  
Dimensional Finite Element ◽  
Experimental Findings ◽  
Three Dimensional Finite Element

The mechanical behavior of the transosseous elements is a defining factor in the overall stiffness, stability, and reliability of an external fixation system. Mechanics involving the application of thin Kirschner wires in Ilizarov apparatus is yet to be fully explained. To address this problem, load-deflection behavior of the pretensioned thin wires laterally loaded by the bone is necessary to be studied. In this paper, the lateral deflections of thin Kirschner wires are studied both theoretically and computationally. Fully three dimensional finite element (FE) modeling and analyses were performed in which the bone was modeled as a hollow cylinder, and the wire-bone interaction was assumed to be frictionless. The mathematical solution resulted in new exact solutions for the deflection as well as final tension in the wires subjected to the lateral loading under a cylinder representing the bone. Results from the FE analyses turned out to be very close to those from the mathematical solution. The results obtained from theory and FE method are comparable to published experimental findings. Some aspects of the pretensioned thin wire behavior in ring fixation systems, e.g., stiffness-tension proportionality, were revealed in the results. The current study adds to the existing knowledge on the general behavior of tensile elements.

Analysis of Polypropylene Deformation in a 135° ECAE Die: Experiments and Three-Dimensional Finite Element Simulations

2009 ◽  
Vol 424 ◽  
pp. 71-78 ◽  
Author(s):  
Ben Aour ◽  
Fahmi Zaïri ◽  
M. Naït-Abdelaziz ◽  
J.M. Gloaguen ◽  
J.M. Lefebvre
Keyword(s):  
Finite Element ◽  
Equal Channel Angular Extrusion ◽  
Deformation Behaviour ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Fe Method ◽  
Saturation State ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Number Of Passes

Plastic deformation of polypropylene (PP) resulting from equal channel angular extrusion (ECAE) process was investigated in a 135° die. A phenomenological elastic-viscoplastic constitutive model was identified and coupled with the three-dimensional finite element (FE) method in order to predict the different processing parameters governing the deformation behaviour of PP during the extrusion. An optimal agreement between FE results and experimental data was obtained for a friction coefficient of 0.2. A detailed three-dimensional FE analysis of stress-strain field distribution was then carried out. The effects of both the number of extrusion passes and the processing routes were experimentally highlighted. The results show that the pressing force decreases with the increase of the number of extrusion passes and reaches its saturation state rapidly for routes A and C while, for routes BA and BC, it requires a high number of passes.

Three-Dimensional Finite Element Modeling for Biomaterial Selection and Shape Design of the Nucleus Prosthesis

2005 ◽  
Vol 475-479 ◽  
pp. 3303-3306
Author(s):  
Qi Jin Huang ◽  
Guo Quan Liu ◽  
Yong Li ◽  
Jin Ji Gao ◽  
Zheng Qiu Gu ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Strain Range ◽  
Biomechanical Analysis ◽  
Low Back ◽  
Fe Method ◽  
Suitable Material ◽  
Prosthesis Replacement ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Nucleus prosthesis replacement is considered as an ideal solution to low back pain. The purpose of this paper is to predict the suitable material properties and shape for the nucleus prosthesis of Chinese people based on biomechanical analysis using three-dimensional (3D) finite element (FE) method combined with experiments. The results suggest that a pillow-shaped nucleus prosthesis made of the polymer biomaterial with a Young’s modulus of 0.1-100 MPa is qualified to replace the degenerated nucleus. Then under the guidance of the FE predictions, a novel nucleus replacement material of polyvinyl alcohol hydrogel was prepared; the mechanical experiment shows that it has a compressive modulus of 1.0-6.8 MPa over a strain range of 10-60 %. The finite element predictions and experimental results have implications for the nucleus prosthesis designs.

AN EFFICIENT PSEUDO THREE-DIMENSIONAL FINITE ELEMENT MODEL: PRESENTATION AND ANALYSIS OF TWO SOIL/FOUNDATION INTERACTION PROBLEMS

2005 ◽  
Vol 02 (02) ◽  
pp. 231-253 ◽  
Author(s):  
DJ. AMAR BOUZID ◽  
P. A. VERMEER ◽  
B. TILIOUINE ◽  
M. MIR
Keyword(s):  
Finite Element ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Element Model ◽  
Combined Loading ◽  
Shear Stresses ◽  
Fe Method ◽  
Dimensional Finite Element ◽  
Soil Foundation ◽  
Three Dimensional Finite Element

A pseudo-three-dimensional numerical model has been developed for the analysis of full 3D soil problems under combined loading. The procedure called Vertical Slices Model takes advantage of finite element (FE) 2D numerical solutions in plane stress for building approximate 3D solutions by replacing the inter-slice interactions by fictitious body forces. Continuum slices are successively analyzed by the combination of the explicit 2D finite element (FE) method and finite difference (FD) method in iterative process. The three-dimensional aspect of the considered problem is preserved by satisfying the continuity of shear stresses developed at the inter-slices. The theory of the vertical slices model is developed first, and then encoded in a Fortran computer program. Next, the prediction capabilities of this program are illustrated with two classical geotechnical applications, namely; the laterally and the axially loaded single piles embedded in homogeneous and non-homogeneous elastic soils. Although approximate, the model proved its ability to capture the behavior of the two boundary value problems. Then, in terms of stiffness factors the approach is used to predict the behavior of an embedded rigid square footing and a pile under combined loading in a half-space where the stiffness shows a power law variation with depth.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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