Stress Distribution on the Boundary of an Elliptical Hole in a Large Plate during Passage of a Stress Pulse of Long Duration (Major Axis Normal to the Wave Front)

Abstract

A solution to the problem of the stress distribution on the boundary of an elliptical hole in a large plate during passage of a compressive stress pulse of relatively long duration is presented. The major axis of the ellipse is normal to the wave front. The solution was experimentally obtained by using a low modulus model material in a combined photoelasticity and moiré analysis. The long-duration stress pulse was applied by loading a small region on an edge of the plate with a falling weight. The results of the investigation indicate that the falling weight loading generates a biaxial state of stress at every point in the plate, which varies with time. The maximum dynamic compressive stresses on the hole boundary can be computed with a fair degree of accuracy by using: (a) the equation of Inglis for the static stress distribution on the boundary of an elliptical hole in any two-dimensional uniform and axial system of combined stress and (b) the biaxial stresses, at the same instant of time, that would have been present at the center of the ellipse if there had been no hole (free-field stresses). The maximum dynamic tensile stresses on the hole boundary were always smaller than the values computed using this same procedure.