Hidden defect identification in carbon fibre reinforced polymer plates using magnetic induction tomography

Carbon fibre reinforced polymer (CFRP) materials pose new challenges to the non-destructive evaluation (NDE) techniques. This study addresses the issue of large defect identification in CFRP plates using electromagnetic measurements. A dual plane magnetic induction tomography (MIT) technique is proposed as a method for damage localization in composite parts, where two arrays of planar sensors are utilized to measure the changes in induced voltages due to the changes in electrical conductivity properties. This geometry meets the requirements of damage inspection in plate structures and thus makes the imaging process feasible. The electrical voltage measurements are used as input to inversely map the spatial resolution of the samples in the region of interest. The stability and detectability of the dual plane system is examined using small metallic cubes. Both individual and multiple instances of damage embedded in CFRP samples are created as a representation of the possible manufacturing defects. Experimental study shows that the presence of damage can be identified in both cases using the dual plane MIT system. With advanced sensing design, rapid data collection unit and improvement in resolution, MIT could become a rapid NDE technique for the integrity inspection of composite structures.