Tensile stress concentration equation for countersunk holes

A detailed three-dimensional finite element stress analysis was conducted for countersunk rivet and straight-shank holes in a plate subjected to tension loading. The study included a wide range of plate width to radius, thickness to radius, and countersunk depth to thickness ratios and countersunk angles ([[theta].sub.c]). The maximum stress concentration occurs at or near the countersunk edge. The stress concentration was found to be a function of countersunk depth, plate thickness and width, and it was nearly independent of the countersunk angle for 90 [less than or equal to] [[theta].sub.c] [less than or equal to] 110 deg. Using the finite element results and limiting conditions of countersunk hole configurations, an equation for stress concentration factor was developed and verified.