Damage detection of CFRP composites using open electrical impedance tomography

Carbon-fiber-reinforced polymer (CFRP) composites derive their excellent mechanical strength, stiffness and electrical conductivity from carbon fibers. The internal damage of CFRP composites, such as fiber fracture and delamination, decreases the conductivity of composite laminates. The present study employs an electrical impedance tomography (EIT) method for monitoring damages in CFRP composites. Traditional EIT is not capable of extracting damage information when the medium is of highly anisotropic electrical conductivity. Therefore, considering the structure and the anisotropic electrical property of CFRPs, this paper presents a method of extracting the damage size and position for anisotropic CFRPs based on open EIT with 6 × 6 electrode array. Five current excitation strategies are compared and evaluated from the perspectives of both measurement and imaging precision. The results show that excited pairs with four intervals have better overall performances, which can provide effective basis for next research step of digging structural damage parameters.