A novel uniplanar multi-electrode capacitive sensor for in-situ weathering damage detection of nonmetallic materials

A uniplanar capacitive sensor with 5-electrodes on one plane substrate and a large reflector electrode, was designed to get the corresponding capacitance information for weathering damage detection of non-metallic materials exposed to a service environment. A 2-D finite-element method was employed to simulate the electric potential distribution and capacitance measurements for the sensor. 2 marble slabs, one was healthy and the other was notched, were experimentally detected, Both the simulation and the preliminary experimental results show that the measured capacitances decrease after weathering damage occurs in nonmetallic material. The reflector can enlarge the sensitive depth. The weathering assessment of nonmetallic materials can be done by processing the measured capacitances. The proposed approach can effectively detect the weathering damage of nonmetallic material and can be practically used for in-situ weathering damage evaluation.