Toggle Main Menu Toggle Search

Open Access padlockePrints

Depth quantification of surface-breaking cracks in ferromagnetic materials using DC-biased magnetization based induction thermography

Lookup NU author(s): Dr Jianbo Wu, Junzhen Zhu, Professor Gui Yun TianORCiD



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


© 2020 Elsevier LtdA common challenge in maintenance of critical structures is how to fast localize and quantify geometries of surface-breaking cracks. Induction thermography (IT) is a potential technique to detect this type of defects. However, for testing ferromagnetic structures, if a deep defect exists in the wall structure, only its shallower part within the skin-depth layer affects the early thermal response of IT, whereas its deeper part hardly has any influence on the early response. To extend the detectable depth range of traditional IT for ferromagnetic materials, a DC-biased magnetization based induction thermography (DCMIT) technique is introduced in this paper. Based on the permeability distortion in the skin-depth layer, DCMIT can build a monotonic relation between the thermal feature and the defect depth. Results show that when the coil direction is parallel to the notch's length direction, DCMIT can quantify the notch with a depth up to 6.0 mm whereas traditional IT can hardly achieve this depth detection.

Publication metadata

Author(s): Wu J, Zhu J, Tian GY

Publication type: Article

Publication status: Published

Journal: Mechanical Systems and Signal Processing

Year: 2020

Volume: 141

Print publication date: 01/07/2020

Online publication date: 20/02/2020

Acceptance date: 05/02/2020

Date deposited: 15/04/2020

ISSN (print): 0888-3270

ISSN (electronic): 1096-1216

Publisher: Academic Press


DOI: 10.1016/j.ymssp.2020.106719


Altmetrics provided by Altmetric


Funder referenceFunder name