Eddy Current Sensor Arrays for Stress and Damage Mapping
Lead Research Organisation:
University of Manchester
Department Name: Materials
Abstract
While eddy current methods are widely used in industry for crack location, very little work has been undertaken in the UK to exploit their potential as a cheap and portable way of sensing stress. Due to the complex nature of electromagnetic interactions with matter, eddy current signals are difficult to interpret and it is currently not possible to unambiguously separate their sensitivities to stress, microstructure and defects. Meeting this challenge requires a multidisciplinary approach; bringing together instrumentation, signal processing with materials science. The 2 teams are well placed to develop the necessary hardware and to begin to establish approximate relationships between the eddy current signature, residual stress, defects, surface geometry and microstructure. This understanding will help us to develop low cost, non destructive eddy current methods for residual stress, active defect detection, and provide guidance for structural integrity engineers regarding the assessment of defects under residual stress loading. To this end we will develop a set of reference samples with quantified levels of stress and damage upon which the techniques will be validated and refined. We will develop and evaluate stress/microstructure/defect imaging from near the surface up to 20mm depth using novel pulsed eddy current sensor arrays along with advanced signal analysis, particularly up to 200mm depth stress distribution of near surface. Huddersfield will design and develop the pulsed eddy current sensors while Manchester has the necessary materials knowledge and complementary stress and damage measurement techniques to validate and evaluate the success of different sensor designs and signal analysis procedures. While the development of a general unambiguous tool for simultaneous stress and damage measurement is some way off, we hope to scope the range of sensitivity of portable prototype eddy current capability to provide cheap, non destructive information about stress and damage levels in specific cases.
Publications
Morozov M
(2013)
Elastic and plastic strain effects on eddy current response of aluminium alloys
in Nondestructive Testing and Evaluation
Morozov M
(2010)
The pulsed eddy current response to applied loading of various aluminium alloys
in NDT & E International
Morozov M
(2010)
Noncontact evaluation of the dependency of electrical conductivity on stress for various Al alloys as a function of plastic deformation and annealing
in Journal of Applied Physics
Zhou D
(2010)
Optimal features combination for pulsed eddy current NDT
in Nondestructive Testing and Evaluation
Description | While eddy current methods are widely used in industry for crack location, very little work has been undertaken in the UK to exploit their potential as a cheap and portable way of sensing stress. Due to the complex nature of electromagnetic interactions with matter, eddy current signals are difficult to interpret and it is currently not possible to unambiguously separate their sensitivities to stress, microstructure and defects. Bringing together the instrument development expertise of Newcastle and the residual stress measurement expertise at Manchester we were able to identify the changes in eddy current signal during deformation and relate these both to the plasticity and the internal stresses. This work provides an initial basis for the application of eddy current monitoring techniqiues for residual stress measurement or quality assurance. |
Exploitation Route | As well as international papers an instrument was developed capable of recording the eddy current signals. |
Sectors | Aerospace, Defence and Marine,Construction,Transport |
Description | QinetiQ |
Organisation | Qinetiq |
Country | United Kingdom |
Sector | Private |
Start Year | 2007 |
Description | Rolls-Royce plc |
Organisation | Rolls Royce Group Plc |
Country | United Kingdom |
Sector | Private |
Start Year | 2007 |