Some Exploratory Photoelastic Studies in Stress Wave Propagation

During the last three years the Guggenheim Aeronautical Laboratory of the California Institute of Technology (GALCIT) has been conducting a photoelastic study of stress wave propagation in solids using a high speed framing camera. This paper presents a technical description of the camera, now operating at 100,000 35 mm frames per second at one tenth microsecond exposure time for an elapsed time of approximately two milliseconds. The design capability is expected to approach a half million frames per second. This equipment has been used to record dynamic photoelastic stress fringe patterns in various specimens under impact loadings. Typical experimental records of wave propagation in cracked plates, layered media, compressed bars and beams, and cross sections of rocket heads are included in this report.