Minimum SCF for Two Neighboring Holes in Disks by Photoelasticity

Abstract

In engineering structures circular holes, or those of other shapes generally occur in groups, thus introducing significant stress concentrations. Minimizing the stress concentration around these holes is an important consideration in engineering design. One of the methods to minimize the stress concentration is to change the hole shape itself until the optimized shape with minimum stress concentration factor (SCF) is reached within specified geometric constraints and loading condition. Using a two-dimensional photoelastic technique, hole shapes have been optimized leading to minimum SCF in diametrically loaded circular disks with two neighboring holes located symmetrically side by side having the load axis perpendicular to the hole axis. Such optimum hole shapes are found to be quasi-trapezoidal with rounded corners. Results are given for a range of disk diameter/hole diameter ratios (11.44=D/d=4.16). In comparison with circular holes, SCF has been reduced up to about 14% with quasi-trapezoidal holes at regions of peak stresses (compressive) and up to 23% at peak tensile stress regions