Inversion Of Multi-Layer Structure Parameters Based On An Electromagnetic/Capacitive Dual-Mode Sensor

A thermal barrier coating (TBC) is a multi-layer structure consisting of an electrically-conductive layer and a non- conductive layer, which can effectively insulate turbine blades from high-temperature gas. If it was to fail, the safety of aircraft engines would face serious threat. Parameter change is an important failure sign of TBCs and it can be detected using different sensors. The existing detection methods can only usually measure a single physical parameter of the TBC, such as the thickness of the ceramic layer. A parameter inversion method for multi-layer structures based on an electromagnetic/capacitive dual-mode sensor is proposed in this paper. After sufficent signal characteristics are obtained using the sensor, the thickness and permittivity of the ceramic layer can be retrieved using a neural network algorithm that has a relative error of less than 4.5% and can meet the needs of engineering applications. This method is also expected to solve the parameter inversion problem of other multi-layer structures.