Stress distribution on the boundary of an elliptical hole in a large plate during passage of a stress pulse of long duration (major axis tangent to the wave front)

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 tangent 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 of 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: (1) the equations 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 (2) the biaxial stresses, at the same instant of time, at a point, symmetric with respect to the center of the hole (free field stresses). The maximum dynamic tensile stresses on the hole boundary were always smaller than the values computed using the same procedure.