关键词: 非金属陶瓷材料;空气耦合超声波;有限元模型;频散曲线

Abstract: Aiming at the problem of air-coupling ultrasonic testing for non-metallic ceramic materials, the mathematic model and the finite element model of air-coupled ultrasonic detection of non-metallic materials was established.Air-coupled ultrasonic propagation dispersion curve and received signals obtained from some node was simulated by the method of Matlab software and ANSYS finite element software, and the propagation characteristics of air-coupled ultrasonic wave in non-metallic ceramic materials were studied.The results show that wave of A0, S0 and SH0 modes in the S3N4 ceramic material as the frequency is less than 2 MHz· mm.When the frequency is larger than 2 MHz· mm, the kinds of wave model is more in the medium.As the distance of wave propagation increase, the received signal amplitude of the A0 modal and the S0 modal is smaller, and the amplitude of A0 modal is larger than amplitude of the S0 modal, so it should stimulate the A0 modal of air coupled ultrasonic for testing and evaluating non-metallic ceramic materials.

Key words: non-metallic ceramic material;air-coupled ultrasonic wave;finite element model;dispersion curve