SMALL-SCALE ALUMINIUM EPOXY PEEL TEST SPECIMENS AND MEASUREMENT OF ADHESIVE FRACTURE ENERGY/

A small 2 mm wide, 25 mm long peel specimen is described which has bee n used to obtain the adhesive fracture energy for specimens comprising a toughened epoxy adhesive with aluminium adherends. The specimen is conveniently made from the unpulled ends of existing floating roller p eel test specimens used by the aerospace industry as part of the routi ne quality control procedures. Specimens were prepared with the thinne r adherend polished down to give specimens with a range of different a dherend thicknesses, with failure occurring at or near the interface b etween adhesive and the adherend oxide. Estimates of adhesive fracture energy for failure in this region were made by using recent analytica l methods. Measurements are also reported on the force required to ben d thin strips with the same dimensions as those used for the peeling e xperiments. These served as a simulation of that part of the peel load due to energy dissipation in the peeling adherend arm, and the result s were compared with predictions. The influence of peel specimen width on measured peeling load is also reported. (C) 1997 Elsevier Science Limited.