Effects with a matrix crack on monitoring by electrical resistance method

Delamination engenders low reliability for primary structures because delaminations of composite laminates are usually invisible or difficult to detect by visual inspections. Automatic systems for in-service delamination identifications are desired to improve this low reliability. The present study employs an electric resistance change method for detection of delaminations. Although the method is effective in monitoring delamination cracks, it requires many experiments to solve inverse problems. An analytical method for preparation of data sets of the electric resistance changes is desired because the experimental cost is high. However, actual delamination cracks usually include matrix cracking. Therefore, this study uses FEM analyses to investigate the effect of matrix cracking on electric resistance changes between electrodes. Results show that simple calculations using a straight delamination crack model are sufficient to obtain the data set of electric resistance changes to calculate response surfaces.