Title: Propagation characteristics of laser-generated like-Rayleigh waves in viscoelastic adhesive coating/substrate structures

Author: GUAN Yijun; SUN Hongxiang; YUAN Shouqi; ZHANG Shuyi; GE Yong

Affiliation: Faculty of Science, Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, et al.

Abstract: The propagation characteristics of laser-generated like-Rayleigh waves in viscoelastic adhesive coating/substrate structures were studied. Considering the viscoelasticity of the coating and substrate, we have established the finite element models in frequency domain for the laser-generated like-Rayleigh waves in the epoxy coating/aluminum substrate, epoxy coating/brass substrate, and epoxy coating/foam substrate structures, respectively. In addition, we have investigated the waveform and propagation characteristics of the like-Rayleigh waves and studied the influences of the coating transparency, coating thickness, coating viscoelasticity, and substrate viscoelasticity on the propagation characteristics of the like-Rayleigh waves. Moreover, we have verified the results by the theoretical phase velocity and attenuation curves. The results show that the coating viscoelasticity induces the attenuation characteristics of the higher frequencies of the like-Rayleigh waves, but has little effect on the lower frequencies, and the substrate viscoelasticity has the influences on both the higher and lower frequencies of the like-Rayleigh waves, especially the lower frequencies. Furthermore, the mode and dispersive characteristics of the like-Rayleigh waves are closely related to the substrates. This study provides a useful theoretical basis for inverting mechanical parameters and evaluating the adhesive quality of the viscoelastic adhesive coating/substrate structures.