Correlation between mechanical damage behavior and electrical resistance change in CFRP composites as a health monitoring sensor

Correlation between mechanical damage behavior and the change of electrical resistance for CFRP (carbon fiber reinforced plastic) composites was experimentally investigated and simulated using neural network approach. Electrical resistance was measured under simple tension and repeated loading–unloading, and observed to remain after removing load. The value of residual electrical resistance was dependent on the maximum strain applied in the past. The failure processes of two types of CFRP were characterized under loading. Consequently, it was revealed that the behaviors of electrical resistance change of two specimens had a close relation with their failure mechanisms. Moreover, the relationship between the applied strain corresponding to the damage, and the electrical resistance change until the ultimate failure of composite was simulated using neural network. There was a fairly good agreement between the simulation and experimental results. It is suggested that this detecting technique is applicable to the health-monitoring of composite structures.