Propagation of S-H Waves in Piezo-Flexoelectric Layered Structures with Imperfect Interfaces: Analytical Formulation and Data-Driven Surrogates

This study presents an analytical and data-driven investigation of shear-horizontal (SH) wave propagation in layered piezo-flexoelectric (PFE) materials with imperfect interfaces. The novelty lies in integrating flexoelectric coupling and interfacial defects within a unified dispersion framework, supported by physics-consistent machine-learning surrogates for efficient parametric analysis. Governing electromechanical equations are formulated and solved under mechanical, electrical, and interfacial continuity conditions to derive dispersion relations linking phase velocity with wavenumber, flexoelectric parameters, and interface stiffness under electrically open and short-circuited boundary conditions. The results show that flexoelectric effects strongly influence dispersion at short wavelengths, while interface imperfections significantly reduce phase velocity and increase attenuation sensitivity. Electrically open conditions enhance electromechanical coupling, whereas short-circuit conditions suppress dispersion sensitivity. To accelerate large-scale evaluations, surrogate models are developed that accurately reproduce analytical dispersion behavior with substantially reduced computational cost. The proposed hybrid framework provides improved insight into guided wave mechanics in stratified smart materials and offers an efficient tool for the analysis and design of piezo-flexoelectric structures in sensing and MEMS applications.