In this paper, experiments have been performed and finite element models have been developed for studying the influence of low-velocity impact damage on the four-probe electrical resistance of carbon fiber-reinforced polymer matrix laminates. Sixteen-ply and 32-ply AS4/3501-6 laminates with quasi-isotropic layup were analyzed. Electrical resistance was evaluated using a four-step procedure. First, finite element models were created in Abaqus Finite Element Analysis (FEA) for simulating low-velocity impact using a quasi-static loading approach. Second, matrix rupture in the inside plies was evaluated, and delamination analysis was performed at the corresponding interfaces to determine delamination patterns. Third, four-probe electrical finite element models were developed in Abaqus FEA for specimens before and after impact using the concept of effective conducting thickness and the delamination patterns obtained from the delamination analysis. Effects of the low-velocity impact delamination on four-probe top and oblique electrical resistance were studied. Electrical resistance predictions were compared to the experimental data. Both top and oblique resistance planes were sensitive to presence of delamination with the oblique resistance measurement being more sensitive as compared to the top resistance measurement. In addition, the resistance of the 16-ply specimens was more greatly affected by the delamination compared to the 32-ply specimens. The proposed analysis can be utilized for design of carbon fiber-reinforced polymer matrix composites with optimized damage sensing capabilities.
Modelling the interfacial damage of carbon fiber reinforced polymer composite laminate under the low-velocity impact loading
