Optimization of uniplanar multi-electrode capacitive sensor for damage detection of aircraft composite material

With the increase of service time of aircraft, the damage in aircraft composite material components may be caused. A uniplanar multi-electrode capacitive sensor is used for detecting the damage in aircraft composite material. In order to improve the sensitivity of the sensor, the optimization for the structure parameters of the sensor with 8 electrodes is carried out. The optimization indexes of the uniplanar capacitive sensor are given and the effects of the structure parameters of the sensor with 8 electrodes on sensitivity are investigated. According to the optimization, a uniplanar capacitive sensor, with 8-electrode on one plane substrate and a ground screen electrode as well as the screen between electrodes, is designed to get the corresponding capacitance information of the measured composite material slab. Two aircraft composite material slabs, one is healthy and the other is notched, are used as a sample for the experiment of detecting the damages. The preliminary simulative and experimental results show that the optimization of the structure parameter of the sensor is important for the sensitivity of the sensor, the measured capacitance decreases after damage occurs in aircraft composite material, and the proposed approach can effectively detect the damage of aircraft composite material.