Finite element analysis of defence hole systems for the reduction of stress concentration in a uniaxially-loaded plate with two coaxial holes

Abstract

A comprehensive plane stress finite element study is made of the effect of three different types of defence hole systems (A, B and C) upon the stress concentration in a uniaxially-loaded plate with two coaxial holes. Throughout this project, the geometry definition, model creation aspects for meshing the plate and generating elements and nodes, model preparation for applying the appropriate loads and restraints, model checking for coincidence nodes and element distortion, and output display of the many cases investigated were all carried out interactively using SDRC (SUPERTAB-IDEAS) pre- and post-processors. The finite element analysis was carried out in the analysis section of the package, known as SUPERB. The study reveals that the introduction of defence holes on either side of the main holes helps to smooth the flow of the tensile principal stress trajectories past the original holes, and thus effect a reduction in stress concentration factor (SCF), an improvement in component strength and a reduction in its weight. Reductions in maximum SCF ranging from 7.5% to 11% have been achieved by the present technique. With such reductions in maximum stress levels, the improvement in fatigue life of a component can be significant.