Shiva Majidnia
Start date: March 2012
Email: shiva.majidnia@brunel.ac.uk
Supervisor: Dr. R. Nilavalan
PhD Research Title: Non-Destructive testing of pipelines using Pulsed Eddy Current
Non-destructive testing (NDT) is commonly used to examine structures in a manner, which will not damage the future usefulness of the material. Flaws can be developed during manufacturing structure and/or service. There are chances of the material used for manufacturing of a structure to already contain flaws. Load conditions, material properties and flaw characteristic will determine whether the serviceability of the structure is affected. Failure in detecting and characterizing of flaws early can lead the structure to fail early or in worse cases cause human loss. NDT is required to detect and characterize the flaws of appropriate severity before the undesirable failures happen. In addition, effective use of NDT can prolong the life of systems without compromising the safety factors and will also offer economic profits.
The use of eddy current for NDT was founded by Friedrich Froster in 1940s.Eddy current sensors exploit the phenomenon of electromagnetic induction. An alternating current passing through an excitation coil will produce a varying magnetic field around it. If an electrically conductive material is brought in the primary magnetic field, eddy current will be induced in the material as practiced by Faraday’s Law. This induced current will then generate an electromagnetic field which will be affected by the flaws inside the material and is measured as an indicator of the presence of a flaw.
This project will focus on development of a pulsed eddy current system for flaw detection and characterization of pipelines over insulation and coating. The potential advantages of PEC systems are:
The ease of scanning large areas of a complex structure without the need to change any set-up parameters.
The ability to compensate during post-processing for lift-off and edge effects.
The speed of acquisition
Instrumentation costs may potentially be lower than for multi-frequency eddy currents.
Publications:
Majidnia, S. Rudlin, J. Nilavalan, R “Depth of Penetration Effects in Eddy Current Testing“ British Institute of Non Destructive Testing (BINDT) Conference. 11-13 September 2012
