Adhesively Bonded Composite Patch Repair in Load‐Bearing Applications for the Aviation Industry: Manufacturing, Design, and Simulation

Four adhesively bonded composite patch repairs are considered: with one and two double CFRP layers and with scarf ratios of 1:15 and 1:30. Prepregs are applied to an artificially cracked aluminum plate and bonded using a film adhesive. Considering curing‐induced deflection of patches, samples with two double CFRP layers and a scarf ratio of 1:15 exhibit the highest deflection, while the patch with one double CFRP layer and a scarf ratio of 1:30 shows the lowest deflection. FE simulations align with experimental results showing deviations between −3% and +16%. Fatigue results of crack length as function of cycles reveal that patched samples have longer lifetimes (3.2–4.3 times) compared to nonpatched samples. Among patched samples, those with two double CFRP layers and a scarf ratio of 1:15 provide approximately 20% and 8% longer service life compared to counterparts with one double CFRP layer and a scarf ratio of 1:30, respectively.