Time-Averaged Photoelastic Stress Analysis of the Ultrasonic Wave in a Strip

Abstract

In this paper, 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, gray level distribution of the photoelastic fringe patterns was formulated and expressed in the form of 1 À J 0 D ð Þ ½ g , where J 0 is the zeroth-order Bessel function. This new technique is called the timeaveraged photoelastic method. To verify the proposed method, the distribution of 1 À J 0 D ð Þ ½ g was superimposed onto the distribution of gray level of the experimentally obtained photoelastic fringe pattern caused by standing wave only. Except regions near the center of fringes, well-matched results were found.

Review of RGB photoelasticity

“…Another field of application of digital photoelasticity regards the time average photoelasticity [36,37].…”

Design of Ultrasonic Horns by Photomechanics Methods

“…Therefore, it is important to investigate not only the wave propagation but also the characteristics of mechanical behaviour in the horn of the ultrasonic machine. To simulate a horn for ultrasonic welding, a strip model incident by an ultrasonic wave was investigated by the time‐averaged photoelastic technique proposed by Wang and Tsai [2, 3]. Stress characteristics generated by the ultrasonic wave can then be readily obtained and the experimental procedures are much simplified.…”