Extended Non-Destructive Testing of Composite Bonds

Composite materials are increasingly being used in the manufacturing of structural components in aeronautics industry. A consequent light-weight design of CFRP primary structures requires adhesive bonding as the optimum joining technique but is limited due to a lack of adequate quality assurance procedures. The successful implementation of a reliable quality assurance concept for adhesive bonding within manufacturing and in-service environments will provide the basis for increased use of lightweight composite materials for highly integrated aircraft structures thus minimizing rivet-based assembly. The expected weight saving for the fuselage airframe is remarkable and therefore the driver for research and development of key-enabling technologies.

The performance of adhesive bonds mainly depends on the physico-chemical properties of adherend surfaces. Therefore, a set of advanced non-destructive testing techniques is applied and adapted to the characterization of CFRP bonded structures as well as the state of adherend surfaces before bonding within the ENCOMB-project. As a medium-scale European Consortium funded within the 7th Framework Programme, ENCOMB (Extended Non-Destructive Testing of Composite Bonds) brings together leading experts in aeronautics research and development providing advanced non-destructive testing methods for reliable quality assurance of adhesive bonds of CFRP structural components. In the following results of two promising measuring techniques both from the field of characterization of adhesive bonds and adherend surface characterization are presented. It is expected that these technologies will have a major contribution to the quality assurance of adhesive bonding in the future.