Tilt effects analysis and evaluation in Pulsed Eddy Current measurements

Abstract

Sensor tilt is regarded as one of the major causes of noise in eddy current testing. A tilted Pulsed Eddy Current (PEC) probe can lead to signal distortion, resulting in errors in measurements and evaluations. For the first time, this paper investigates the tilt effect on PEC signals by developing an analytical solution for tilted PEC sensors. The analytical solution combines the theory of mutual impedance variation of tilted coils with PEC testing. It is found that the impact of tilt angles on PEC signals follows a double-exponential function in terms of both amplitude and the decreasing rate of transient voltage change. Corresponding experiments have been conducted, which agree well with the numerical results and validate the analytical solutions. Additionally, a sensor tilt angle estimation method based on the double-exponential relationship curve is developed and an average absolute error of 0.2829° has been achieved.