Pulsed eddy current stimulated thermographic NDE

Lead Research Organisation: Newcastle University
Department Name: Electrical, Electronic & Computer Eng


Pulsed eddy current stimulated thermography is a novel non-destructive evaluation (NDE) technique that employs an infrared camera to detect defects, typically cracks at the surface of a component, by imaging the effects that they have on the heating of a component produced by a pulsed eddy current heating system. To date, eddy currents in the 50-200 kHz range have been generated in a test-piece using a conventional eddy current heating system with a simple, two or three turn, encircling coil. Cracks block the flow of eddy currents and significantly alter current flow lines in their vicinity. The Joule heating caused by the eddy currents can be imaged by an infrared camera, providing a means of detecting cracks by imaging the characteristic effects that they have on eddy current distribution. The method is considerably quicker than conventional ultrasonic or eddy current inspection techniques that require point by point scanning. Whilst impressive results have been achieved in a small number of laboratories, the system, particularly the excitation, needs engineering. The reliability of the system needs to be investigated as there is concern that defects in some locations on a component may be missed; this is a function of the eddy current density that is generated across the surface of a component by the excitation system. In addition, results to date are rather qualitative with little indication of defect detectability or its dependence on system, defect or test-piece parameters. This proposal is for a scientific investigation of the eddy current excitation requirements for a reliable eddy current stimulated thermography inspection system and measurements to determine the defect detection capabilities of such a system. The plan is for a two person-year project in which the first year will be based at Newcastle with the work focussed on the modelling of the requirements of the eddy current excitation system and on researching the design and construction of a suitable system. The second year will be based at Bath where the system will be used to research defect detection capabilities. Two types of excitation system will be investigated. One for the testing of small components that can be placed within an encircling coil and the other for the testing of larger components which will be progressively tested using a coil to produce heating in a localised region of the component. Practical specimens will be provided by the industrial collaborators, Rolls-Royce and Astom Power. The project will involve in-depth modelling of the eddy current density induced in the surface of a specimen and its heating effect at cracks of different size set at different orientations and locations across the component. The effects of changing the orientation of a specimen within the eddy current coil will be modelled to establish inspection measurements that should lead to the detection of defects set at all orientations within the specimen. Experimental studies will be made of the performance of the system in detecting and imaging defects of different sizes, shapes and orientation. The performance of the technique will be compared with the other thermographic NDE methodologies: optical stimulated, conventional transient thermography and acoustically-stimulated thermosonics. The overall aim of the project is to perform a thorough scientific investigation of a promising new NDE technique that is needed before the technique can be introduced successfully into industry.


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Wilson J (2010) Pulsed eddy current thermography: system development and evaluation in Insight - Non-Destructive Testing and Condition Monitoring

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Wilson J (2010) Modelling and evaluation of eddy current stimulated thermography in Nondestructive Testing and Evaluation

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Wang Y (2016) Diffusion and separation mechanism of transient electromagnetic and thermal fields in International Journal of Thermal Sciences

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Li K (2014) State Detection of Bond Wires in IGBT Modules Using Eddy Current Pulsed Thermography in IEEE Transactions on Power Electronics

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Gao B (2018) Physics-Based Image Segmentation Using First Order Statistical Properties and Genetic Algorithm for Inductive Thermography Imaging. in IEEE transactions on image processing : a publication of the IEEE Signal Processing Society

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Gao B (2014) Thermography pattern analysis and separation in Applied Physics Letters

Description New eddy current pulsed thermography have been developed. Simulation models e.g. multiple physics integration, different experimental systems and quantitative NDE have been applied worldwide e.g. applications in Canada, China, UK, India and Malaya.
Exploitation Route Several research agreement have been signed to Universities and industries for different applications.
Our relevant publication has been well-cited e.g. high h-index
L Cheng, GY Tian, Surface crack detection for carbon fiber reinforced plastic (CFRP) materials using pulsed eddy current thermography, Sensors Journal, IEEE 11 (12), 3261-3268, 2011
Sectors Aerospace, Defence and Marine,Electronics,Energy,Manufacturing, including Industrial Biotechology,Retail,Transport,Other

Description More than ten systems have been developed and applied in UK, China, Malaya etc. Beneficiaries: Acadmic and industry Universities: Bath University, Nanjing University of Aeronautics and Astronautics, Zhejiang University, University of Electronics Science and Technology, Hebei university of technology Industry: Rolls Royce, Network Rail, Alstom, Chinese high-speed railway, aerospace industry Contribution Method: NDT system and NDE Applications
First Year Of Impact 2017
Sector Aerospace, Defence and Marine,Energy,Manufacturing, including Industrial Biotechology,Transport,Other
Impact Types Economic

Description Chongqing University
Amount ¥120,000 (CNY)
Organisation Chongqing University 
Sector Academic/University
Country China
Start 03/2010 
End 02/2013
Description EMAT based Pipeline integrity
Amount £62,000 (GBP)
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 08/2016 
End 03/2017
Description EPSRC IAA 3D eddy current thermography
Amount £58,835 (GBP)
Funding ID    EP/K503885/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 07/2016 
End 03/2017
Description Game changer Proposal and Poster
Amount £5,000 (GBP)
Organisation National Nuclear Laboratory 
Sector Public
Country United Kingdom
Start 09/2016 
End 03/2017
Description Hebai University
Amount £17,000 (GBP)
Organisation Hebei University of Technology 
Sector Academic/University
Country China
Start 03/2013 
End 05/2015
Description NDTonAIR: Training Network in Non-Destructive Testing and Structural Health Monitoring of Aircraft structures
Amount £189,034 (GBP)
Funding ID 722134 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 04/2017 
End 04/2020
Description NUAA university fund
Amount £18,000 (GBP)
Organisation Nanjing University of Aeronautics and Astronautics 
Sector Academic/University
Country China
Start 08/2012 
End 04/2013
Description Royal Society
Amount £50,000 (GBP)
Organisation Royal Academy of Engineering 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2011 
End 02/2012
Description Alstom 
Organisation Alstom
Country France 
Sector Private 
Start Year 2008
Description GE PII 
Organisation ZONARE Medical Systems, Inc.
Country United States 
Sector Private 
PI Contribution Knowledge transfer through KTP
Collaborator Contribution KTP
Impact Ongoing
Start Year 2016
Description Rolls-Royce plc 
Organisation Rolls Royce Group Plc
Country United Kingdom 
Sector Private 
Start Year 2008