Propagation characteristics of acoustic emission signals in solid-liquid-solid coupling interface

The propagation path of acoustic emission (AE) signal contains several structures with solid-liquid-solid coupling interfaces. In this paper, the effect of the coupling interface on the AE signal propagation is investigated. Based on the theory of Lamb wave, a solid-liquid-solid coupling interface model is designed. The propagation char-acteristics of the AE signals with different frequencies are predicted by simulation in the coupling models with different oil film thicknesses and contact areas. Furthermore, experimental verification is carried out. The results of the experiments are consistent with the numerical simulations. The results indicate that the oil film thickness and the center frequency will have an effect on the propagation of AE signal. Two passing coefficients are proposed to quantify the propagation characteristics. This paper provides guidance for the study of the AE signal propagation characteristics in the complex structure with multi-media interfaces.