Paper number 268

STRENGTH OF ADHESIVE BONDED COMPOSITE LAP SHEAR JOINTS WITH AND WITHOUT EMBEDDED CRACKS

Liyong Tong

Department of Aeronautical Engineering, University of Sydney, NSW 2006, Australia

Summary

An experimental and numerical study is presented to investigate the effect of a crack embedded in the continuous adherend at an overlap end on failure behavior of an adhesive-bonded composite lap shear joint. In the experimental part, illustrated are the effect of the crack length on failure mechanism and loads. It is found that the presence of a crack at the overlap end can significantly reduce the static failure loads of the lap shear joints. For example, the failure load of a joint with a 10 mm long crack can be decreased by up to 44% comparing to that of the non-cracked one. Finite element method is then used to study the effect of the crack on both peel and shear stress distributions in the adhesive layer. The mode I and II energy release rates are also calculated using the virtual crack closure integral method, and then used to interpret the failure mechanism.

Keywords

damage tolerance, crack, energy release rate, failure mechanism, failure load, lap shear joint.