Detection of delamination in graphite/epoxy composite by electric potential method

The amount of delamination in graphite/epoxy composite laminate was measured using resistance change of a plate. Initially cracked DCB (double cantilever beam) composite specimens were fabricated and mode I interlaminar fracture test was performed. Resistance change increased as the crack propagated and the change was larger for the thinner specimen. Relation of resistance change and crack growth rate showed nonlinear behavior and could be simplified as a parabolic equation. Proposed empirical equation which included thickness effect of composite plate will be utilized to detect and measure the inner flaw such as delamination of a fiber reinforced composite laminate.