Electrical Resistance Tomography (ERT) applied to Epoxy composites

Polymer composites like epoxy are widely used in high performance engineering applications requiring electrical insulation and/or mechanical strength and resistance to cyclic stresses. Over time, multi-stress aging can result in progressive degradation of the polymer. The current work studies the possibility of damage detection in epoxy through electrical resistance tomography. In electrical resistance tomography (ERT), current is injected at known points in the sample, and the resultant potential difference between given points is measured. For this purpose, an array of electrodes is placed along the boundary of the sample. Further, this technique requires the conductivity of the polymer to be increased to measurable values, and this is done by incorporating carbon-reinforced fibers into the matrix to form a Carbon Fiber Reinforced Polymer (CFRP). A finite element method (FEM) based model is developed to model the electrical resistance tomography measurements in epoxy-based CFRP in the presence of simulated defects. The ERT measurements are observed to be sensitive to the presence of defects.