Damage Detection in Carbon Fibre Reinforced Composites Using Electric Resistance Change Method

In the present study, 2-D numerical analyses of strip-type specimens of laminated composites with and without damage are considered and numerical investigation is carried out by using the finite element program ANSYS. Electrical conductivity of the composite laminate in the longitudinal direction is given constant, while electrical conductivity in the through-thickness direction is used as a variable in the parametric study. The resistance changes for each case due to delamination is estimated by comparing the obtained resistance with the corresponding value of the specimen without delamination. The surface and oblique resistances are numerically calculated according to the two-probe and four-probe methods. The results obtained show that the four-probe method for the resistance measurements is valid only when the through thickness conductivity is comparable to the longitudinal conductivity. The present study shows that the resistance percentage change is dependent on the location of electrode pairs used for the resistance measurement with the respect to the location of delamination Thus, the resistance percentage changes could be used not only for the detection of the presence of delamination but also for the localization of delamination.