Two-dimensional electrical potential inversion of damage morphology in carbon fiber composite laminates with co-cured probe

Carbon fiber composites are susceptible to external threats during service due to their linear elastic mechanical behavior and brittle fracture failure characteristics. Therefore, accurate, timely, and effective structural health monitoring of carbon fiber composites has become particularly important. Carbon fiber has good conductivity, making it possible to monitor damage using the electrical potential method. In this study, we set up three different diameter sizes of probes ( ∅ = 5, 10, and 15 mm) and solidified them with plain-woven laminates through co-cured technology. The ∅ = 15 mm probes can achieve accurate measurement of in-situ resistance by using the four-probe method. The sensitivity of the two-dimensional electrical potential method to the damage morphology of plain-woven composites under different current loading modes was analyzed by presetting defects in laminates. It was found that electrical current injection mode affects the accuracy of electrical potential changes. The damage positions in the oblique current injection mode are all near the electrical potential peak and valley. The electrical potential field disturbance caused by damage inside the plain-woven laminates is not significant. Compared to the oblique current injection modes, the accuracy of the damage area obtained by the potential-based damage monitoring in the direct current modes is higher. Under the direct current injection, the maximum electrical potential change rate reaches 200% after damage compared to the intact state. The offset length between the maximum value of the electrical potential change map and the damage area edge is 20 mm, indicating that the potential damage morphology is not completely consistent with the damage area. The electrical potential damage map obtained through the inversion algorithm can locate the damage location. These results provide new ideas for improving the sensitivity of the electrical potential method for structural health monitoring.