Evaluation of defects in adhesive joint by doubie cantilever beam experiment

摘要

We analyzed effects of interface/adhesive defects during fracture mechanical Mode I Double Cantilever Beam (DCB) tests of an adhesive joint. Two aluminium slabs were bonded using structural epoxy adhesive. A DCB experiment under static loading was conducted to estimate the critical fracture energy. During the 'steady-state' fracture we noted oscillating, random fluctuation in the force vs. displacement curve, and thus in the fracture energy. This is associated to the local variation of properties within the bondline and the interfaces. A simple model is derived to quantify the probable density of flaws observed experimentally.