The effect of number of electrodes and diagnostic tool for monitoring the delamination of CFRP laminates by changes in electrical resistance

The present study employs an electric-resistance change method for the identification of delamination cracks. In this method, the appropriate number of electrodes for identifing delaminations is investigated, and the diagnostic tool for the inverse problems to identify the delamination crack location and size from the electric resistance changes is discussed. FEM analyses are conducted to obtain electric resistance changes due to delamination crack creation with three-, four- and five-electrode type specimens. By the use of artificial neural networks (ANNs), the required number of electrodes for the identification of delamination-crack location and size from the electric resistance changes is investigated. By comparison of the estimations with the ANNs and with the response surfaces (RS), a better diagnostic tool is discussed in detail. As a result, the five-electrode type specimen is shown to be better for identification, and use of the RS with quadratic polynomials is a better tool than ANNs for the identification of delamination-crack location and size using electric resistance change.