Imaging and detection of cracks in metallic structures with eddy current sensors

Abstract

In this paper we propose an original analytical modeling applied to electromagnetic (EM) systems, in the aim of performing an inversion scheme. The purpose consists in imaging cracks through eddy current sensors, the image being constituted by an estimation of the conductivity of the piece of metal under test, voxel by voxel. There are plenty of industrial applications in Non Destructive Evaluations for monitoring of cracks in structures: Aeronautics, Metallurgy, ships building and so on. For modeling, a relatively new developed technique, called 'Distributed Points Source Method' (DPSM) has been used. This original modeling was invented at Ecole Normale Superieure of Cachan in 2000, and since developed and patented in many kind of applications (Ultrasonics, Electrostatics…).

Wireless passive sensor based on microstrip antenna for metal crack detection and characterization

“…This sensor detects cracks with a width of less than 1 mm at a frequency of approximately 20 GHz, which significantly increases the cost of measurements. (2) An eddy current sensor can detect cracks in the metal surface and cracks inside the metal [11][12][13], but it requires a relatively large power and its resolution is insufficient to determine the position and size of the crack. (3) Ultrasonic sensors can detect cracks in relatively large areas by studying the interaction between ultrasonic waves and cracks [14][15][16], but ultrasonic interrogation is susceptible to various noises, and signal processing is very difficult.…”