Multi-material adhesive joints with thick bond-lines: Crack onset and crack deflection

Abstract This study investigates the fracture onset and crack deflection in multi-material adhesive joints with thick bond-lines ( ? 10  mm) under global mode I loading. The role of adherend-adhesive modulus-mismatch pre-crack length are scrutinized. parameters controlling path directional stability also discussed. Single-material (i.e. steel-steel GFRP-GFRP) bi-material steel-GFRP) double-cantilever beam bonded a structural epoxy tested. modelled analytically, considering on elastic-plastic foundation, to include characteristic scales problem (e.g. thickness , plastic zone) numerically using Finite Element Model . An empirical relation, terms geometrical material properties joints, that defines transition between non-cohesive cohesive is found. Above specific stress singularity at tip rules over near corners, resulting mid-adhesive onset. However, cracking direction rapidly deflects out from layer centre-line. Positive T-stress along found be one factors for unstable path.