Geometry Optimization of Resonance Acoustic Emission Sensors

Abstract

Acoustic emission (AE) sensors are used for non-destructive damage inspection of structures, and their performance can be improved through geometry optimization. For versatile usage, low impedance values over a wide frequency range are required, and this characteristic depends on the geometry of the PZT assembly. In this study, the performance of various sensor models is compared using finite element analysis, and a resonant AE sensor with better performance than a commercial sensor is suggested. Various shapes of the AE sensor are modeled, and while fixing the voltage at the bottom of the PZT to 0 V, harmonic voltages in the range of 10 kHz to 1 MHz are applied to the top of the PZT. Then, the impedance is calculated with the numerically induced current. The impedance-frequency curves are obtained as a simulation result, and it is found that the number of resonance points and the corresponding impedance value at the resonance point vary depending on the diameter, width, or thickness of the ring and disk part of the sensor. As the area of PZT increases, the impedance of the model decreases, and the thickness of PZT with the best performance is 2.6 mm. The result of this study can be used to improve the performance of the resonance AE sensor.