Recent Developments of Multi-Elements Eddy Current Probes

摘要

Eddy Current technique is a powerful mean of detection of surface breaking flaws in the conductive components. In the context of increasing requirements for improving the detection capabilities of smaller flaws while reducing time of inspections, new high resolution array probes are a very attractive solution which overcomes the limitations of classical sensors. In this communication we present recent developments of such probes carried out at CEA LIST. Two different technologies will be described: flexible array of micro-coils etched on kapton and array of Giant Magneto-Resistance (GMR). The flexible array probe has been developed for aeronautical applications and is dedicated to the detection of cracks in parts of complex geometries. The flexible technology greatly reduces the lift-off noise, optimizes the coupling between the sensors and the part and consequently enhances the detection of small flaws. The GMR sensors, thanks to their small size and their sensibility, make possible the design of arrays showing a very high spatial resolution. In the two cases, the design of the probes has been optimized by simulation, using CIVA software. During the presentation, we describe this design and show the performances of the probes on experimental results.