Laser ultrasonic damage detection in coating-substrate structure via Pearson correlation coefficient.

Abstract This study explores the feasibility of using laser generated ultrasonic wave to detect the interfacial damage of coating-substrate structure. Two Pearson correlation coefficient based post processing algorithms are respectively modified and used in order to evaluate the damage-induced waveform variation and thus position the damage accurately. In addition, the ultrasonic signals of frequency-domain and time-domain are separately studied to optimize the damage visualization performance of the two approaches. The proposed method helps to facilitate nondestructive examination of laser ultrasonic technique. Highlights • Pearson correlation coefficient is used to process the laser induced acoustic wave. • The proposed damage edge threshold can be used for the damage region determination. • Frequency-domain processing algorithm is suitable for the no-intact-specimen case. • Time-domain processing algorithm is suitable for the intact-specimen-provided case. [ABSTRACT FROM AUTHOR]