Impact-damage visualization in CFRP by resistive heating: Development of a new detection method for indentations caused by impact loads

Rapid and automatic inspection of composite aircraft after every flight would reduce the safety factor and allow for more flights. Although, an electrical resistance change method (ERCM) has been proposed, there are many problems with its practical application. In this study, a new diagnostic method, impact-damage visualization, was developed. Indentation damage increases fiber–fiber contact at the interlaminar interface and electrical conductivity. Consequently, electrical current applied to the material will concentrate around the damaged area, and lead to selective and intense resistive heating. This temperature increase can be observed by thermography or detected as a change in electrical resistance caused by the temperature difference. The proposed method had sufficient reliability and sensitivity for practical application as a damage inspection method.