Residual Tensile Strength of Adhesively Bonded Double Lap Joints after Transverse Impact

The aim of this study was to understand the effects of transverse impact on the residual tensile strength of double lap joints. The experimental results were compared to baseline cases with no impact damage. The adherend and adhesive used were the Hexcel Hexply® IM7/8552 and Hexcel Redux® 319 respectively. During impact, delamination occurred within the 0° ply at the inner adherend surface ply opposite to which the impact was applied. A significant decrease in failure load was also found from the following residual tensile strength tests for the impact case compared to the pristine case. While the failure mechanisms were similar, the reduction of residual strength appears to be mainly due to the presence of the sharp crack as a result of the impact, the decreased effective overlap length of the specimen and the lack of intact adhesive fillets after the impact.