Stress analysis of steel/carbon composite double lap shear joints under tensile loading

Abstract

The study is related to adhesive-bonded long overlap double lap shear joints with thick adherends. The outer adherend is based on crossply carbon fibre/epoxy composite laminate and the inner adherend is mild steel. The paper aims to predict and assess the structural failure of the joint, including delamination of the composite and to determine the effects of the design parameters of adherend thickness, overlap length and fabric orientation on the joint’s failure. Both experimental and numerical methods were used for the analysis. The experimental programme includes fabrication, mechanical testing and failure examinations of various joints. The numerical methods are based on 2-D models using strength-limit and cohesive zone modelling methods, taking into consideration the composite properties of the plies and the resin layers separating them. The study showed a good agreement between the numerical and experimental results. Key conclusions in relation to the failure and design parameters of the joints are made.