Eddy current array : an alternative to conventional surface NDT methods

Raude, Ang‚lique; Eddyfi Europe; France

Raude, A.; Eddyfi; Canada
Sirois, M.; Eddyfi; Canada

ID: ECNDT-0116-2018
Session: Civil Infrastructure - ET, UT
Room: J1
Date: 2018-06-12
Time: 15:40 - 16:00

A large number of Non-Destructive Techniques (NDT) have been developed and successfully used over the past decades for the detection of surface breaking flaws in various materials, such as: cracks, pitting, corrosion, etc. Those are more or less sophisticated, but all provide valuable information on the integrity of the component being inspected, and come with specific advantages and limitations.
Established methods such as penetrant testing (PT) and magnetic particle inspection (MPI) are effective but can lack practicality in some applications. Others, such as conventional eddy current inspection technique (ECT) mainly deploy single element probes resulting in protracted inspection times. Results are also typically greatly affected by operator’s skills, material properties and geometry.
Advances in electronics enabled the development of more modern inspection techniques like Eddy Current Array (ECA), increasing the reliability of surface inspection over traditional methods. Indeed, being able to tailor coil designs and multiplexing patterns allows users to optimize the acquisition chain to their specific application. Moreover, by multiplexing and leveraging advanced data processing capabilities, ECA solutions allow inspections to be carried out quickly, often with less surface preparation. They also provide additional benefits such as state-of-the-art imaging (e.g. 2D and 3D C-Scan displays), improved surface coverage, ease of deployment and data archiving. Finally, on top of defect detection, ECA technology can also provide quantitative sizing.
This paper describes the eddy current array method along with variations on the theme, inclusive of their benefits and limitations. The deployment of ECA on real components, subject to representative field conditions is also discussed. Typical applications are presented, providing valuable insights on the use of ECA in lieu of more conventional techniques.