Damage Detection for CFRP Based on Planar Electrical Capacitance Tomography

Due to the widespread use of carbon fiber reinforced polymer/plastic (CFRP), the nondestructive structural health monitoring for CFRP is playing an increasingly essential role. As a nonradiative, noninvasive and nondestructive detection technique, planar electrical capacitance tomography (PECT) electrodes array is employed in this paper to reconstruct the damage image according to the calculated dielectric constant changes. The shape and duty ratio of PECT electrodes are optimized according to the relations between sensitivity distribution and the dielectric constant of different anisotropic degrees. The sensitivity matrix of optimized PECT sensor is more uniform as the result shows, because the sensitivity of insensitivity area can be increased by adding rotation of optimized electrodes. The reconstructed image qualities due to different PECT arrays and different damage locations are investigated at last. The simulation results indicate that: PECT can be used to detect the surface damage of CFRP; the sensitivity matrix of PECT for CFRP is highly relevant with the degree of anisotropic dielectric constant; the rotatable PECT sensor with rotation has better performance in uniformity of sensitivity; for different damage locations, the rotatable sensor with rotation has better image quality in most cases.