Abstract
Based on the time-averaged technique, a digital photoelastic system was employed to observe the stress distribution generated by an ultrasonic wave impinged at the edge of a strip. According to the classical photoelastic theory, light intensities emerging from the analyzer were formulated and expressed in the form of |1-J 0 (Δ)|, where Jo is the zeroth-order Bessel function. This new technique is called the time-averaged photoelastic method. To verify the proposed theory, the distribution of |1-J 0 (Δ)| was superimposed onto the distribution of gray level of the experimentally obtained photoelastic fringe pattern. Except regions near the edges and the center of fringes, qualitatively well-matched results were found.