APPLICATION OF ELECTRIC-POTENTIAL METHOD TO SMART COMPOSITE STRUCTURES FOR DETECTING DELAMINATION

CF/epoxy composites have been applied to many kinds of aircraft struct ures. The composite laminated plate compression properties, however, a re easily degraded by delaminations. Thus an approach for detecting th e delaminations is widely desired. In this study, an electric potentia l method was discussed for realtime nondestructive evaluation of delam inations because this method has several advantages in comparison with the embedded optical fiber. In order to obtain the basic properties o f the CF/epoxy composites, mode I and II delamination tests were carri ed out and the relations between the electric resistance change and th e delamination crack length were measured. As a result, the electric r esistance bridge circuit approach was proven to be excellent for detec ting delaminations from the inside surfaces of aircraft structures.