Three-Dimensional Finite Element Analysis of Un-Cemented and Cemented Femoral Prostheses Implanted under Different Bone Densities

2014 ◽  
Vol 510 ◽  
pp. 302-306
Author(s):  
Dong Song Li ◽  
Shu Qiang Li ◽  
Bo Cai ◽  
Wei Feng ◽  
Jian Guo Liu

Objective Three-dimensional finite element analysis was employed to select femoral prostheses according to different bone densities, and simultaneously simulated contrast mechanical tests were performed to determine the age criteria regarding the selection of femoral prosthesis during the hip replacement. Methods Three-dimensional finite element models of femur were established using Solidworks software. Following the known formula, the bone density and elastic modulus at different age brackets were calculated and input into the computer. The human one-foot standing condition was simulated and pressure was loaded on the reconstructed femoral models. Some iomechanical characteristics of un-cemented and cemented femoral prostheses, such as the distress distribution and initial micro-movement at different bone densities, were measured. Results Relatively well-distributed whole distress and slight initial micro-movement of un-cemented femoral prostheses were found in male patients at 30-60 years old and in female patients at 40-55 years old. Symptoms of cemented femoral prostheses the same as the un-cemented femoral prostheses were present in male patients at 60-70 years and in female patients older than 55 years old. Conclusion Results of three-dimensional finite element analysis and simulated contrast mechanical tests suggest that un-cemented femoral prostheses provide better therapeutic effects in male patients younger than 60 years and in female patients

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

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.


2021 ◽  
Vol 11 (3) ◽  
pp. 1220
Author(s):  
Azeem Ul Yaqin Syed ◽  
Dinesh Rokaya ◽  
Shirin Shahrbaf ◽  
Nicolas Martin

The effect of a restored machined hybrid dental ceramic crown–tooth complex is not well understood. This study was conducted to determine the effect of the stress state of the machined hybrid dental ceramic crown using three-dimensional finite element analysis. Human premolars were prepared to receive full coverage crowns and restored with machined hybrid dental ceramic crowns using the resin cement. Then, the teeth were digitized using micro-computed tomography and the teeth were scanned with an optical intraoral scanner using an intraoral scanner. Three-dimensional digital models were generated using an interactive image processing software for the restored tooth complex. The generated models were imported into a finite element analysis software with all degrees of freedom concentrated on the outer surface of the root of the crown–tooth complex. To simulate average occlusal load subjected on a premolar a total load of 300 N was applied, 150 N at a buccal incline of the palatal cusp, and palatal incline of the buccal cusp. The von Mises stresses were calculated for the crown–tooth complex under simulated load application was determined. Three-dimensional finite element analysis showed that the stress distribution was more in the dentine and least in the cement. For the cement layer, the stresses were more concentrated on the buccal cusp tip. In dentine, stress was more on the cusp tips and coronal 1/3 of the root surface. The conventional crown preparation is a suitable option for machined polymer crowns with less stress distribution within the crown–tooth complex and can be a good aesthetic replacement in the posterior region. Enamic crowns are a good viable option in the posterior region.


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