Analysis of rubber adhesive : FE simulation of damage propagation over rubber adhesive under fatigue in mixed-mode loading

Abstract: This thesis refers to a simulation of an adhesive joint used to bond two metal sheets of a component of the side skirt bracket implemented in trucks. The adhesive joint must support fatigue and mixed-mode loading. The principal goal is the implementation of a novel material model, which governs the damage produced by a mixed-mode fatigue loading in a rubber adhesive layer. Two approaches to define the material model are implemented: the filament model and the principal strain model. The models are fitted against experiments, which have been performed parallel to the development of this thesis by the Mechanics of Materials (MoM) research group of the University of Skövde. The models incorporate fitting parameters with the aim of adjusting the models against experimental results. Simulations are performed using the Finite Element (FE) software, ABAQUS, and the material models are implemented using UMAT subroutines. The filament model is inaccurate and it is considered unable to model the mixed-mode behaviour of the adhesive joint. The principal strain model is considered a well-established method to define the damage and to predict the fatigue life of the adhesive under fatigue in mixed-mode loading.