Measurement of applied and residual stresses using an ultrasonic instrumentation system

Theory, instrumentation, and several applications are discussed for an ultrasonic system capable of measuring applied and residual stresses in commercial alloys. The instrumentation is designed to measure the time of flight of an ultrasonic wave transmitted through a material with a resolution of 0.1 nanosec. Two types of transducers have been tested and found to produce linear relationships for the change in time of flight vs the change in applied elastic stress. Materials tested include 2024-T351 aluminum and AISI-SAE 1018 low carbon steel.