Failure analysis of crack-prone joints with Finite Fracture Mechanics using an advanced modeling approach for the adhesive layer

Abstract

When adhesive joints are subjected to critical loads, the components can separate at the interface between the adhesive layer and one of the adherends. Due to the strongly differing stiffness properties of the adherends and the adhesive, which cause stress peaks to arise locally at the edge of the joint, a crack grows into the structure there once the critical load is reached. The concept of Finite Fracture Mechanics allows reliable failure assessment and determination of this critical load. For this purpose, a coupled criterion consisting of an energy and a strength criterion is evaluated, both of which must be satisfied simultaneously in case of failure. In this work, Finite Fracture Mechanics is evaluated analytically and using finite element data and compared and discussed with experimental results. In the analytical approach, the focus is on extended applicability to joints with both thin and thick adhesive layers, for which an advanced modeling approach of the adhesive layer is used.