Reflection and refraction of SH waves at a combined interface

In the present paper, we investigated the reflection and refraction of SH waves at a non-ideal interface between two elastic half-spaces. By modelling the non-ideal interface as two thin membranes (in the scope of surface/interfacial elasticity) and a layer of springs between the two membranes, we established a combined model for the non-ideal interface. We analytically derived the reflection and transmission coefficients as well as the phase shifts of the reflected and transmitted waves under this new model. This combined interface model can degenerate to other interface models by taking certain limits of the interface parameters. To learn more about the nature of the interface models, we presented numerical examples of the reflection and transmission coefficients and the phase shifts under various interface models.