Understanding of Materials State and its Degradation using Non-Linear Ultrasound Approaches for Lamb Wave Propagation

This research work was a continuation effort on earlier work efforts focused on the development of better understanding of non-linear ultrasonic methods for quantitative materials state evaluation and characterization of damage in metallic alloys. In this work, the Non-linear ultrasonic NLU method using guided Lamb modes was explored. Creep and associated damage mechanisms were simulated on metallic alloys of steel using standard test coupons that were subjected to different tempering temperatures. The results show that the Lamb wave NLU method can distinguish the different regions of damage. The improved understanding of the nonlinear ultrasound is anticipated to lead to new measurement techniques with applications in the area of vehicle health monitoring, nondestructive testing, and monitoring of manufacturing processes.