Estimation of stress concentration factor for a plate with hole under axial tension loading

Abstract

The purpose of this study is to investigate the effects of hole/holes on stress concentrations in a plate using a current industry standard software - Finite Element Analysis (FEA). Plate with hole/holes is a common engineering application such as in automobile, marine, aerospace and mechanical structures. Hole/Holes can be seen in many thin-walled mechanical and automobile structures and components. For example, hole/holes are found in residential/commercial buildings’ steel structural studs to allow plumbing installation, web or flange of steel box girders in bridges is furnished with holes to ease inspection works, electrical and heating conduits in the walls or ceilings and ribs attached to the main spar of an aeroplane’s wing are frequently come with holes. These hole/holes are one type of discontinuities within the structure (e.g. thin plate) that leads to changes in elastic stiffness and may tend to failures. Proper knowledge of stresses, strains, deflection and stress concentration (SC) are required to design any structures. In the geometry of the plate, under different loading, stress concentration rises from any abrupt change. And due to this, throughout the cross-section, the uniform stress distribution does not occur. At a point of stress concentration, as a results failures like fatigue cracking and plastic deformation commonly occur. Hence, it is very important in any engineering structural design to know about the stress concentration on plates with holes. In the present study stress concentration in a plate with a circular central hole and offset hole subjected to uniaxial loading (axial tension) is calculated using Finite Element of Analysis (FEA). Equations of SCF given by Peterson are dependent on three parameters namely, hole radius (a), distance from the bottom edge to the centre of hole (c) and distance from top edge to centre of hole (e). By varying either ‘c’ or ‘e’ or the ratio of ‘e/c’, an effort is made to study stress concentration factors for the determination of the edge effect by varying the hole to edge distance. The results show that von Mises stresses increased with increasing ‘e/c’ or ‘a/c’, which in turn increases SCF and finally leads to failure.