Thermography assisted characterisation of production-induced defects in CFRP and their influence on the mechanical behaviour

A novel hybrid-joint, suitable to series production, is currently developed. It over comes the gap in stiffness by inserting a thermoplastic element between metal and carbon fiber reinforced polymer (CFRP). The main goal in terms of quality assessment is to characterise the defect-caused damage propagation (effects of defects) by means of destructive and non-destructive testing (ndt) of artificially implemented defects. Assuming that flaws are most-likely to occur within the CFRP, close to the transition zone, first investigations are carried out on the effects of defects in pure CFRP component. Thus artificially implemented defects, i.e. missing roving, gapping, 10° misalignment, pleat and delamination, are characterised by active thermography interms of type, size and location. A subsequent correlation of the mechanical properties under quasi-static tensile tests and fatigue experiments of a defect-free reference and the imperfect samples is carried out. In order to evaluate the damage propagation, the mechanical experiments are complemented by in situ passive thermography.