Design of a novel DCB for signal processing of in-situ ECNDT in aviation

In the aviation in-situ eddy current non-destructive testing (ECNDT), there are increasing requirements for speediness, intelligence and integration. The signal conditioning bridge ciruit is one of the most important parts for realizing the requirements. This work proposes an approach to develop a novel digitally controlled bridge (DCB), which is based on relay arrays. It is used for impedance signal processing of ECNDT sensor in aviation in-situ testing. The design ideas, theory analysis, bridge structure, method of realization and performances are presented. A practical in-situ eddy current testing experiment on the aero-engine labyrinth disc was carried out and the experimental results testified the availability and advantages of this work.