Nonlinear Ultrasound for Damage Detection and Localization in Aluminum Alloy Thin Plates

Aiming at the damage characteristics of aluminum alloy thin plate which is prone to cracks and holes during service, this study proposes a localization method based on the relationship between the nonlinear ultrasonic coefficient and the ultrasonic propagation distance as well as the ultrasonic propagation path offset damage distance. First, the selection of ultrasonic frequency and nonlinear ultrasonic coefficient are determined according to the propagation characteristics of Lamb waves. Secondly, the relationship between the nonlinear ultrasonic coefficient and the ultrasonic propagation distance as well as the damage distance offset from the ultrasonic propagation path is analyzed through the finite element model, and the precise positioning of the damage location is realized by analyzing the change of the nonlinear ultrasonic coefficient. Finally, the method is experimentally verified in aluminum alloy thin plate, and the experimental results show that the method can accurately identify the damage in aluminum alloy thin plate and locate it precisely, which verifies the effectiveness of the method.