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

Abstract

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 localisation in composite parts, where two arrays of planar sensors are utilised 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 possible manufacturing defects. Experimental study shows that the presence of damage can be identified in both cases using 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 the composite structures.

Comparing and improving techniques for conductivity image reconstruction in MIT: A simulation study

“…Typical values contrast category f σ (S/m) Explanation Low 1-10 MHz 0.1-10 Medical and industrial applications 8,9 Middle 0.05-1 MHz 10-14 4 Applications for imaging regions with carbon fibers 12 or biomedical conductive polymers 13 High 5-100 kHz 10 4 -10 7 Industrial applications 10…”

Simulation research of impact of number of coils in EMT sensors on reconstructed images quality

“…Sensitivity matrix reflects the refined change of induced voltage due to the change of conductivity distribution inside imaging region. The relationship is expressed as follows [11]…”

“…Simulations and laboratory experiment results verified the feasibility of the EMT method with L-shaped sensor. Ma and Soleimani [11] addressed the issue of hidden defect identification in carbon fibre reinforced polymer (CFRP) using a dual plane EMT sensor array.…”

Numerical-Experimental Investigation into the Tensile Behavior of a Hybrid Metallic–CFRP Stiffened Aeronautical Panel

“…In the literature, the damage behavior of composite materials has been widely investigated, pointing out the effects in terms of induced damage of impacts with foreign objects [9][10][11][12][13][14], of the manufacturing or the assembly processes [15][16][17][18] and, finally, the effects of service loading conditions.…”