The effect of electrical anisotropy on delamination detection sensitivity for structural health monitoring of laminated composites

In the present work, both theoretical analysis and experimental tests have been carried out on the electrical response of unidirectional Carbon Fiber Reinforced Polymer (CFRP) laminate with delamination to investigate the effect of electrical anisotropy on damage detection. Finite element modelling (FEM) has also been performed to explore the potential distribution in damaged laminates with different electrical anisotropy ratios. The simulation results demonstrate that the damage detection sensitivity and sensing zone varies with the electrical anisotropy. Subsequently, by incorporating a prior parameter to avoid oversimplification, a theoretical model is proposed to predict the change in electrical resistance of CFRP laminate as the length of delamination increases, and it is validated through a series of double cantilever beam (DCB) tests on CFRP laminate with different electrical anisotropy ratios. The experimental results indicate that introducing the conductive interleave significantly reduces the electrical anisotropy ratio of CFRP laminate, improving the damage sensitivity. This agrees well with our simulation and modelling results.