Quality assurance concepts for adhesive bonding of aircraft composite structures by extended NDT
The integration of innovative lightweight materials like CFRP into multi-material design (MMD) environments in aeronautic applications brings along a paradigm shift in initial design, manufacturing and in maintenance, repair and overhaul (MRO). Essential cost reductions over the whole aircraft lifecycle demand innovative processes meeting the specific requirements of MMD in general and specifically of CFRP. The certification of (structural) adhesive bonding marks a key step for full integration of CFRP, as adhesive bonding is the optimum CFRP joining technology. As yet, difficulties in predicting and assessing the bond quality by non-destructive testing limit the certification of adhesive bonding technologies and subsequently their usage in aeronautic applications. ComBoNDT (Quality assurance concepts for adhesive bonding of aircraft composite structures by extended NDT) aims at overcoming these limitations through the enhanced development and maturation of extended non-destructive testing (ENDT) methods suitable for pre- and post-bond inspection of adhered surfaces and adhesively bonded joints. The ComBoNDT approach is threefold and includes:
reliable and reproducible detection of undefined and/or multiple contaminations on surfaces prior bonding, triggering surface cleaning and activation measures
reliable and reproducible detection of poor bond quality, triggering appropriate repair actions
improvements in robustness of methods addressing the requirements of in-line inspection in both aircraft manufacturing and MRO environments.
Time savings of up to 70% and cost savings of up to 50% in related production, MRO and retrofit processes are expected from the application of ENDT technologies resulting from ComBoNDT. The project addresses relevant levels of technology and of manufacturing readiness. ComBoNDT will contribute to the implementation of safe, cost- and time-efficient adhesive bonding technologies and to the reduction of production and MRO costs.