Backing layers on electroacoustic properties of the acoustic emission sensors

Abstract The acoustic emission sensors were tailored by using Piezoelectric Lead Zirconate Titanate (PZT) ceramic as sensing element and different materials as backing layers. The influences of backing layers on electroacoustic properties of the sensors were investigated based on the pencil lead break test and simulated noise experiments. The results show that compared with PZT ceramic, the resonant frequency of the acoustic emission sensors decreases due to damping effects from backing layer and the metal shell. The backing layer of air has the largest acoustic reflection coefficient, and epoxy resin/tungsten powder has the largest acoustic attenuation performance, which is benefit to improve the bandwidth of the acoustic emission sensor. The acoustic emission sensors made of different backing layers own good reception ability to acoustic emission signals, and the characteristic parameters analysis results prove their good identifying ability to effective acoustic emission signals and noise signals.