Pre-cracking behaviour in the single cantilever beam adhesion test

摘要

The single cantilever beam adhesion test is a variant of the asymmetric wedge test in which a constant load is attached to the free adherend end to originate the moment required for joint fracture. It has the potential disadvantage of leading to an uncontrollable, accelerating crack, due to the constantly increasing applied couple, but presents the advantage of providing data on joint behaviour prior to crack initiation. It is this latter aspect that we consider in this paper. An apparently decreasing crack growth rate, as obtained from measurements of displacement of the free end of the beam is attributed to time-dependent adhesive strain. Use of classic, simple beam theory and Winkler, elastic foundation, equations allows us to assess an effectively static fracture energy, or fracture threshold.