Usage of coil-shaped conductive polymer composite as intrinsically flexible flaw sensing probe

The assessment of buried flaws in the interlayer structure of curved metal is crucial to system safety. To improve the flexibility of eddy current sensor, an intrinsically flexible flaw sensing probe made of coil-shaped conductive polymer composite is proposed. The experimental data show that the response signal of the coil-shaped composite changes at the flaw and increases with the increases of flaw height/length, with a maximum sensitivity of 0.435 mV/mm for differential amplitude and 4.904 °/mm for differential phase. The results show that the height of the characteristic signals in the response signals reflects the change in flaw height, and the length of the characteristic signals in the response signals reflects the change in flaw length. The relative change rate of the coil-shaped composite is higher than that of a metal coil of the same structure. The above results have laid a preliminary foundation for using the coil-shaped composite to detect flaws.