Size-dependent interfacial elasticity effects on SH wave propagation in cylindrical structures

Abstract This work presents a novel analytical framework for shear–horizontal wave transmission in a viscoelastic cylindrical structure incorporating a novel strain gradient elastic membrane of Aifantis-type at the interface. The framework’s formulation integrates viscoelastic constitutive behavior with Aifantis-type gradient elasticity to capture size-dependent microstructural consequences that classical interface theories are unable to represent. By treating the membrane as an infinitesimally thin gradient-enhanced imperfect interface, the study constructs a dispersion relation that concurrently accounts for interfacial stiffness, strain gradient contributions, and viscoelastic attenuation. This unified formulation reveals significant modifications in phase velocity, attenuation, and stress distribution caused by membrane microstructure and geometric parameters. The proposed approach offers a fundamentally new perspective on guided-wave behavior in layered cylindrical media and establishes a versatile analytical tool for advanced wave-based diagnostics, interface characterization, and the design of next-generation viscoelastic and microstructured cylindrical systems.