A nonlocal strain gradient framework for smart composites with surface energy and sliding interface conditions

In response to the aerospace industry's demand for lightweight smart structures, this study provides a comprehensive analysis of the interplay between nonlocality, strain gradient effects, sliding dynamics, phase and group velocity phenomena in composite plate systems featuring a sliding interface. The analysis incorporates stress, electrical displacement, and magnetic flux continuity conditions across the interface, alongside stress-free and insulation constraints at the upper and lower surfaces. By incorporating surface effects and sliding boundary conditions, the dispersion relation is established through a determinant-based analysis of the resulting system of equations. The proposed framework advances the understanding of wave propagation in multiscale composite systems, offering insights for designing microscale sensors and adaptive devices in smart material applications.