Improving Inspection Reliability through Data Fusion of Multi-View Array Data

Lead Research Organisation: Imperial College London
Department Name: Dept of Mechanical Engineering

Abstract

The objective of this project is to obtain a step-change improvement in the detection and characterisation of defects in safety-critical components across a range of industries including nuclear power generation and the defence sector. This will be achieved through data-fusion of the multiple views of a component's interior that can be obtained through modern ultrasonic array imaging techniques. Previous work by the team has demonstrated a two-order-of-magnitude improvement in detection performance when data fusion was applied to ultrasonic data obtained from separate scans performed with single-element probes. This was in a case where the expected defects were small, point-like inclusions that scatter roughly uniformly in all directions. The proposed project will develop the data-fusion philosophy for improving defect detection performance from multi-view array data in the much more complex case where the defect morphology cannot be assumed in advance and the scattering pattern may be strongly directional. Therefore, the project will necessarily address the critical challenges of applying data fusion to defect classification and sizing from multi-view array data. Demonstrator software will be produced that will show an image of the test component with indications ranked by the probability of them being produced by a defect; it will then be possible to probe any of these indications to show detailed classification (e.g. crack, void, inclusion etc.) and sizing information. The project is supported by EDF, Hitachi, BAE Systems and AMEC Foster Wheeler.

Planned Impact

Reliable, quantitative detection and sizing of defects with a minimum of false calls is a key industrial requirement; it is a particular issue in the run-up to the building of new nuclear power plant where the aim is for longer service life and reduced in-service inspection. In recognition of the importance of reliable post-manufacture inspection, the proposal is supported by the main players EDF, Hitachi and AMEC Foster Wheeler, as well as by BAE Systems who have parallel issues on submarine structures. The industrial partners are contributing £180k cash as well as considerable in-kind support in the form of data from industrial test-pieces and tests conducted according to new protocols. The project is an excellent fit to the 5-10-20 year vision produced by the industrial members of UK Research Centre in NDE (RCNDE) so the whole industrial membership has strong interest in the findings.
The immediate communication route for the results of the project to industry will be directly to the four industrial collaborators, both through the formal 6-monthly review meetings and via frequent direct liaison between the researchers and company contacts. As the collaborators have specified the inspection applications to be implemented in the demonstrator software that will be developed, the work will have rapid industrial impact. The project is particularly timely since the improved detection and sizing methods developed will be in time to be qualified for use on new-build nuclear plant. AMEC Foster Wheeler are key to this as they are heavily involved in inspection qualification and will be carrying out validation tests as an integral part of the programme. It should be stressed that the demonstrator software is solely for trial purposes - before inspections using it could be qualified for use on the safety-critical components of interest to the collaborating companies, it would have to be re-written to industry standards and incorporate the features required for it to be usd in the field; this would be commissioned and paid for by industry.
The primary communication route to the wider industrial community will be via the RCNDE Technology Transfer workshops. These annual 1-day events are open to both RCNDE core industrial members (primarily end-users of NDE) and RCNDE associate members, the latter comprising both large global companies and SMEs, mostly from the NDE supply chain. The workshops are run with the express purpose of aiding the exploitation of findings delivered from the RCNDE and typically attract participants representing ~30 different companies. The workshops include both presentations and table-top demonstrations of RCNDE research.
To reach the international academic community, the work will be presented at the main academic and industrial NDE conferences, as well as more general meetings to expose the work to, for example, the biomedical and geophysical communities. The key scientific findings will of course be published in top academic journals, with examples of practical usage appearing in suitable applied venues.
The IP arising from the project will be owned by the universities. As our motivation for performing the work is to improve the performance of inspections for safety-critical plant, we intend to place as much scientific knowledge in the public domain as possible; we (the universities) will not seek to profit directly from this. Similarly, the demonstrator software will be made freely available for non-commercial use, as we believe that this is the best route to gaining industrial acceptance.

Publications

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Description We have made a very good start towards the objective of fusing different views obtained from an ultrasonic array using full matrix capture to give improved inspection of welds. A satisfactory means of registering the different views has been developed and a rational way of weighting them has been produced. The next step is to finalise the characterisation and sizing strategy. This is in progress and we are drafting two key papers on the detection and characterisation of defects and the merits of fusion.
Exploitation Route We are disseminating regularly to our industry partners
Sectors Aerospace, Defence and Marine,Energy