Stress separation by block integration

The need for more comprehensive investigations of both two- and three-dimensional photoelastic models requires that stress separations should be undertaken in significant volumes of material. The method described in this paper is based upon the existing integration procedures which only yield separate stresses along a selected line. A modification of the method for measuring the isochromatic fringe number and the use of graphical techniques allows a significant reduction to be made in the time required for line integrations, without loss of accuracy. Acceptable results have been obtained for integrations passing through regions of stress concentration which would not be amenable to easy analysis by conventional methods.