Analysis of shear horizontal waves in heterogeneous/microstructural coupled plates: exploring the influence of interfacial bonding and the boundary conditions

Shear horizontal waves serve as guided waves for inspecting large, inaccessible areas across various engineering and scientific fields, including sensors, structural health monitoring, and non-destructive evaluation techniques. The dispersion characteristics of SH waves, characterized by a single displacement component, render them highly suitable for a wide range of applications. In this study, the propagation of SH waves is examined in coupled plates comprising two distinct plates of finite thickness. One plate is a microstructural couple stress plate, while the other is heterogeneous. The analysis explores both perfect and imperfect bonding conditions at the interfacial surface of the coupled plates. Additionally, the analysis examines eight different sets of boundary conditions at both the interfacial and free boundaries of the plate, including stress-free, clamped, and mixed types. Dispersion relations are derived in all cases by applying an analytical approach resembling the variable separable method. Graphical interpretations have been provided to assess the impacts of various parameters, such as characteristic length, heterogeneity, thickness, and imperfectness on the phase velocity of shear horizontal waves.