Advances in the Bondline Control Technology for the Certification of Adhesively Bonded Composite Repairs

Adhesively bonded composite repairs restoring limit load capacity are not yet certified in civil aviation due to a lack of methods suitable for the substantiation of proper bond quality. In our previous paper, we proposed a novel method for process control to resolve this issue. The core of this bondline control technology is a new type of adhesion test that provides proof of bond quality and simultaneously serves as a robust surface pre-treatment for adhesive bonding. The present study describes improvements implemented in the adhesion test and demonstrates the ability of the test to detect bonding defects. Furthermore, the applicability on stepped surfaces common for repair scenarios is investigated. Finally, a test series on the quality of the surface pre-treatment is presented.