Numerical study on delamination detection in I-section GFRP beam with optical fiber-based ultrasonic technique

In order to overcome the effect s of FRP multi-interface, high damping characteristics and diversity of the body wave mode on the ultrasonic nondestructive test, a novel technique for detecting delamination is proposed. A PZT transmitter was employed to create the stress waves in the beam, and an optical fiber interferometric sensor was attached to the surface of the beam to detect the stress wave propagation in the beam. By analyzing the propagation characteristics of ultrasound and the wavelet time-frequency spectrum of the signal, the delamination location can be identified. Based on the theoretical analysis and simulation results, the feasibility of delamination detection with the proposed technique is demonst rated.