Failure load prediction of structural adhesive joints

Abstract

Abstract This paper describes an analytical method for calculating the strain energy release rate of cracked adhesive joints. The calculations proceed from a knowledge of the reactions in the adherends at the end of the joint overlap. For joints with equal adherends, a simple method exists for determining the Mode I and Mode II components of the energy release rate. The equations make it relatively easy to apply fracture mechanics failure criteria to arbitrarily loaded adhesive joints. In a subsequent paper, it is shown that by treating uncracked joints as having a crack, with the crack tip coinciding with the location of the spew fillet, the load required to propagate a crack in a cracked joint serves as a reliable conservative estimate of the load required to propagate a crack in an uncracked joint. The present method is suitable, therefore, for failure load predictions of structural adhesive joints in design applications.