Failure analysis of adhesive bonded joints with defects using non-local continuum damage models in FEM

The failure behaviour of adhesive bonded joints, predicted using continuum damage models through the finite element method (FEM), is one of several effective approaches. However, despite its widespread use for modelling various failure mechanisms, conventional FEM often produces mesh-dependent results and sometimes fail to converge, particularly in complex scenarios such as joints with adhesive defects, including sharp cracks. Non-local approaches, which account for the influence of surrounding regions, effectively address these challenges and produce numerically converged structural responses. In this work, integral-based non-local strain theories are employed to analyse the failure behaviour of problems across various modes where FEM encounters difficulties. A mixed-mode continuum damage model, utilising a quadratic stress and linear fracture energy criterion, is adopted to capture the linear damage evolution in adhesively bonded joints. To illustrate the capability of the proposed methodology in achieving mesh independence and stable iterative convergence for relatively medium sized meshes, numerical examples of adhesive joints with an interfacial sharp crack are analysed under both independent and mixed-mode loading conditions.