Measurements of Stress Waves in Solids by Dynamc Photoelasticity

The technique of dynamic stress-birefringence has been applied in two unique ways to a study of stress waves in solids. Observations of both longitudinal and shear waves, induced in Plexiglas by a pulsed beam of high-energy electrons, have been made with a polariscope operating in the visible. Stress waves induced in silicon by an exploding wire facility were studied with the polariscope in the infrared. The theories of thermoelasticity and birefringence are reviewed briefly and solutions describing stress induced by transient energy depositions are obtained. These solutions are compared to experimental results obtained with a flash x-ray generator.