Abstract:
Currently, the nonlinear ultrasonic detection technique is a research hotspot in the field of nondestructive testing. In this paper, the research background and principles of nonlinear ultrasonic detection technique are introduced; and then the nonlinear ultrasonic characterization methods are briefly summarized, including high harmonic characterization methods, frequency-mixing characterization methods, and the analysis methods of nonlinear ultrasonic signals. The current application status of nonlinear ultrasonic detection technique are reviewed from the aspects of damage assessment, damage localization and life prediction. Finally, it is shown that there still exist great errors in the detection results of the current nonlinear ultrasonic testing technique mainly due to the influences of system nonlinearity, detection environment and impure signal extraction. In addition, the future research directions are discussed based on the error sources.