ON THE FRACTURE PARAMETERS IN A CLAMPED CRACKED LAP SHEAR ADHESIVE JOINT

A stress analysis using a beam theory approach similar to that suggested by Goland and Reissner is undertaken for a clamped crack lap shear (CLS) adhesively bonded joint. Analytical solutions of the normal and shear stresses in the adhesive are derived for the simple case where the lap and the strap have equal thickness and moduli. In a subsequent step, these expressions are used in the framework of a crack-closure technique to obtain the Mode I, Mode II and total energy release rates for a crack propagating along the bondline. For an illustrative example, a comparison with a finite element analysis showed reasonably good agreement. This closed-form approximation of both the Mode I and Mode II components of the energy release rate allows the use of fracture mechanics to describe debond growth in mixed-mode conditions representative of actual structures.