A numerical model for thick composite-metallic adhesive joints

This paper presents the formulation of a new material model that is particularly well adapted to the description of failure within thick ductile adhesive joints. The adhesive is described as an isotropic material and its plastic behaviour is modelled through a Von Mises yield criterion combined to a piecewise linear hardening law and holds some similarities with the cohesive zone modelling techniques that are of great use for the description of composites delamination (e.g. the material is degraded through a cohesive law). Unlike the more traditional adhesive modelling approach that uses interface elements, the element for adhesives failure is a solid formulation. There is thus no need for a-priori knowledge of the crack path. Parameter identification for the new adhesive model is performed through an inverse method on data extracted from end-notched flexure (3ENF) and Double Cantilever Beam (DCB) tests carried out on specimens made from adhesively bonded woven glass/epoxy composite panels. The model and calibration procedure is validated by comparing predictions with experimental results for tensile tests of a metal to composite double-lap joint specimen.