Finite Element Analysis of Perforated Plates Containing Triangular Penetration Patterns of 5 and 10 Percent Ligament Efficiency

1975 ◽  
Vol 97 (3) ◽  
pp. 199-205 ◽  
Author(s):  
D. P. Jones

Two- and three-dimensional finite element models were used to determine elastic stress distributions in plate ligaments for various in-plane, bending, and thermal loadings. Plates containing triangular penetration patterns of 5 and 10 percent ligament efficiency were analyzed as well as the example of a circular plate containing a single centrally placed hole subjected to step change in temperature on one surface. Detailed descriptions of boundary conditions are given with the results presented in terms of stresses important in tubesheet and vessel closure design considerations. Results show that the minimum ligament section of the perforated region need not be the critically stressed cross section as is currently assumed in the ASME Boiler and Pressure Vessel Code. Further, a thermal shock ΔT applied to the surface of a perforated region will result in a maximum peak stress of EαΔT/(1−ν) and may be significantly lower than the thermal skin stress calculated by the ASME Code procedures.

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2666
Author(s):  
Jae-Hyun Lee ◽  
Ho Yeol Jang ◽  
Su Young Lee

The present study was designed to compare the stress distributions in two restoration types of implants and the surrounding bone. The first restoration type was a conventional cement-retained zirconia crown, and the second was a novel cementless screw-retained zirconia crown with a base abutment. A three-dimensional finite element method was used to model the implants, restorations, and supporting bone. A comparative study of the two implants was performed under two masticatory loads: a vertical load of 100 N and a 30-degree oblique load of 100 N. Under both loading conditions, the maximum von Mises stress and strain values in the implant and supporting bone were higher in the conventional cement-retained restoration model than in the cementless screw-retained model. In terms of stress distribution, the cementless screw-retained zirconia crown with base abutment may be considered a superior restoration option compared to the conventional cement-retained zirconia crown.


1983 ◽  
Vol 105 (2) ◽  
pp. 171-176 ◽  
Author(s):  
T. D. Brown ◽  
G. L. Hild

Three-dimensional finite element analysis is used to explore the influence of several lesion characteristics upon mechanical stress distributions in segmentally necrotic human femoral heads. Variables studied parametrically included apparent modulus deficits within the lesion proper, as well as the depth, width, and location of the infarcted head regions. The detailed patterns of stress redistribution were complex and were found to be a strong function of the specific lesion characteristics. The salient phenomenon, however, was one of preferential load uptake by the stiffer bone surrounding the lesion. Since computed stress reductions within the infarctions were usually much smaller than experimentally observed strength reductions, the data suggest a strong tendency for an elevated incidence of trabecular fatigue fractures in the affected regions.


1996 ◽  
Vol 5 (5) ◽  
pp. 096369359600500 ◽  
Author(s):  
F. Z. Hu ◽  
C. Soutis

The purpose of this paper is to evaluate a recently developed analytical model [1] which determines the interlaminar stress distributions around a circular hole in symmetric composite laminates under in-plane tensile loading. For this purpose, a three-dimensional finite element analysis is performed and the stress distributions for symmetric cross-ply laminates are presented This work is relevant to the prediction of delamination onset load and location around the discontinuity.


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.


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