Non destructive evaluation of artificially induced damage in composite structures using electrical resistance/potential mapping

Since delaminations of composite laminates are usually invisible or difficult to detect by visual inspections, delamination causes low reliability for primary structures. Automatic systems for delamination identifications in-service are desired in order to improve this low reliability. At the present work electrical potential technique was applied to detect and locate artificial damage in carbon fiber reinforced polymer (CFRP) patched plates. The potential distribution across the surface of the laminates was measured using a grid pattern of 117 electrical contacts on several current injection topologies. A constant current of 1 A was applied to the plate, and the differences in the potential distribution between the virgin plate and five scenarios of damaged plates were recorded and presented graphically in order to define the best current injection topology. Simultaneously a finite element study realized for the same scenarios and using a fine-tuned Matlab visualization code we were able to identify the location and geometry of the artificial damage for all damaged scenarios.