Mode I and II fracture of adhesive joints

Abstract

The compliance method is used to determine strain energy release rates in mode I and II fracture of adhesive bonded joints. A strong dependence of the strain energy release rates upon the adhesive thickness is found. Standard compact tension and compact shear specimens are used. It is found that the former are well suited to the investigation of mode I fracture, but that the latter are less well suited to mode II investigations. Attention is focussed on bond failures caused by cracks propagating between an adhesive and an adherend. Experimental and theoretical arguments are combined to determine the critical strain energy release rates at which such failures occur. The critical values are shown to be strongly dependent upon the method of surface preparation as well as upon the physical properties of the materials used.