Damage Modelling in Adhesive Butt Joints under Torsion via Imperfect Interface Models

We report on an analytical model for damage description in adhesive butt joints. In the model, the thin adhesive layer is replaced by a damaging bonding interface. The mechanical behavior of the interface is described by a nonlinear and rate-dependent imperfect contact law. The law takes into account both stress and displacement jumps, and it can describe both soft and hard adhesive layers. Unlike classic cohesive zone models, phenomenological in nature, the proposed contact law explicitly accounts for material and damage properties of the adhesive layer. A first comparison with literature data of adhesive butt joints loaded in torsion indicates that the model can successfully reproduce their experimental stress-strain response.