Generalized interfaces enabling macroscopic modeling of structural adhesives and their failure

Abstract

This contribution presents a geometrically linear and thermodynamically consistent model for generalized mechanical interfaces. The interface’s response is kinematically non-coherent, i.e. allows for a displacement jump and for anisotropic cohesive failure, and kinetically non-coherent, i.e. allows for traction jumps across the interface and membrane damage. The traction jump ensues from an interfacial (in)elasticity formulation which introduces additional membrane stiffness and membrane stresses under in-plane stretch in the interface. The cohesive and membrane degradations are coupled via damage variables determined by the different deformation modes to account for their interaction. A numerical example applies the presented model to brittle interfaces adhesively bonding two substrates. By subjecting the interface to a small in-plane stretch prior to performing a peel test, the influence of damage coupling on the mechanical response is illustrated.