Abstract:
To realize the aircraft carbon fiber reinforced composite (CFRP) plate in service inspection, the eigenvalue imaging based on air-couple ultrasonic lamb waves was used to detect the CFRP plates. The A0 mode lamb wave of the CFRP plate was generated and received by a pair of 0.4 MHz air-coupled ultrasonic transducers at same side. The two D-scans were used to obtain the lamb wave signals for eigenvalue imaging in mutually perpendicular directions. The damage indexs (DI) which represented the characteristic parameter of eigenvalue imaging were established by the method based on the time domain, frequency domain and time-frequency domain. By means of full multiplication fusing, the eigenvalue images were translated into the 2D image which could present the actual position and size of defect.