Research Fields

 

The PRISM research group is part of UoA 28 which achieved a 4-rating in RAE 2001. Performance, reliability and integrity of structures and materials are critical issues underpinning a highly mobile, communication-driven and microprocessor-dependent society. Improvements rest on development and detailed characterisation of advanced and engineered materials; on property and performance optimisation through sophisticated manufacturing and fabrication; on statistically reliable life prediction techniques; and on development and improvement of engineering codes and standards. These factors influence optimum usage of resources, materials and engineering assets, and therefore form an important part of the sustainability agenda. The PRISM group mission is to contribute to technological improvement in particular areas of regional and national importance through linking analytical and numerical modelling with sophisticated characterisation and experimentation. This has been achieved via national and international multi-disciplinary consortia (e.g. FaME38), and requires explicit consideration of both fundamental engineering science and applied engineering impact. Thus members of PRISM have a strong profile in industrially supported research, particularly Knowledge Transfer Partnerships, CASE studentships, and advanced strain scanning.

PRISM encompasses structural integrity and optimisation of design, manufacturing and fabrication processes. It has links with Structures and Conceptual Modelling (submitted in UoA 27) and Industrial & Engineering Mathematics and includes the Advanced Composites Manufacturing Centre (ACMC). Research foci are design and fabrication process optimisation for performance (metals and composites), the characterisation and influence of residual stresses on fatigue performance, and fundamental understanding of crack growth mechanisms. The impact and reach of this work is evidenced internationally by the leading role of the group in strain scanning; Editorship of the International Journal of Fatigue (MN James); research on galvanising high performance steels (supported by the UK Galvanisers Association, European General Galvanisers Association and the International Lead Zinc Organisation); and regionally by the large KTP portfolio and its influence on industrial practice (evidenced below).

FaME38 is the Facility for Materials Engineering , established in 2001 as a joint venture between the EPSRC, the Institut Laue-Langevin (ILL) and the European Synchrotron Radiation Faculty (ESRF) in Grenoble, France. The ILL and ESRF are, respectively, European central facilities for neutron and synchrotron radiation research and are operated and funded by consortia in which the UK is a major partner through the EPSRC and the CCLRC. FaME38 has had a major impact on advancing the world-leading position of the UK strain scanning community; in extending synchrotron and neutron radiation use by UK engineering academics and industry in relation to critical problems in residual stress assessment, life prediction, damage and crack growth mechanisms, optimisation of weld processes, and surface engineering processes. Its pan-European impact, internationally leading reputation and profile are evidenced in the highly positive comments made by the Chief Executive of the CCLRC, John Wood in his presentation at the 40th anniversary celebration of the ILL on 17 January 2007 and in the strong increase in experiment applications to the ILL-ESRF which request support from FaME38. Experiment 7-01-196 with MN James as PI, using the advanced SALSA hexapod strain scanning instrument, was chosen by the ILL for inclusion as a prestigious Scientific Highlight in the Materials Section of the ILL Annual Report 2006.

Diffraction strain scanning is a powerful advanced engineering tool used in understanding and optimising alloy processing, structural fabrication, life prediction and integrity issues. PRISM researchers collaborate on major research projects, e.g. the SEALS (Stress Engineering Application to Large Structures) project, headed by BAE Systems and Airbus UK which aims to develop stress-engineering techniques for friction stir welds in the aerospace sector.

The strong links between applied and fundamental research and their regional reach is evidenced in work led by ACMC (Grove, Summerscales): with Vestas Technology where manufacturing time for a 49 metre wind turbine blade was reduced to 24 hours through radical change of manufacturing, with subsequent work on fundamental causes of product quality variation through an EPSRC CASE studentship; research with Plastech which led to 3 TCS/KTP programmes, a DTI (Zero Emissions Enterprise) consortium, and an EPSRC CASE studentship; a British Patent Application (Summerscales) GB0523581.7: Production of composite mouldings (2005). The national and international reach is evidenced in the generation of €200k income through FaME38 from industrially funded experiments, e.g. Corus Research & Development, Airbus UK, British Energy, Rolls Royce, Messier Dowty, Dunlop Aero Braking Systems and ESKOM, South Africa; the award (MN James) of two research contracts after international tender from the International Lead Zinc Research Organisation in North Carolina, USA (ZC-21-1 ‘Galvanising High Performance Steels for the Construction Market’). These are concerned with the multi-million dollar industrial problem of avoiding cracking in structural steelwork during the galvanising process. The results of this work are feeding back into new guidelines for galvanising high performance steels and the work has high impact on standards in the galvanising and construction industry (UK, Europe and the US).

Output from advanced experimental facilities needs to be interfaced with sophisticated analytical and numerical modelling to allow extrapolation from limited data into predictive tools. This aspect includes work by Hall on tyres and highlights the importance of the IEM group in the context of UoA 28 seen, for example, in the novel work by MN James, Aron, Christopher and Patterson (Michigan State University) on interpreting stress fields around fatigue cracks through linking analytical modelling of stress terms (including elastic-plastic boundary stresses and wake contact stresses) with full-field analysis of photoelastic fringe patterns (EPSRC grant GR/L42391 for £124,216 – EPSRC IGR ranking ‘Tending to Outstanding’ with Airbus equipment support). Results have been presented in keynote lectures at the 8th International Fatigue Congress, Stockholm, Sweden (2002) the 5th International Conference on Fatigue Damage of Structural Materials, Hyannis, MA (2004) and the 10th International Conference on the Mechanical Behaviour of Materials, Busan, Korea (2007).

Performance and process optimisation research includes the complex relationships between properties-for-performance and properties-for-manufacture in fibre composites, this includes resin transfer moulding and resin infusion under flexible tooling. Outcomes include a major capability and cost-effectiveness increase in manufacture of components for the new Airbus A380 aircraft (GKN Aerospace) through heated tooling and resin film infusion techniques; increased electrified train operation speeds via a redesigned novel composite hanger for the overhead power lines (Vortok International, Plymouth). It also includes weld life prediction that links energy input with residual stresses, defects and performance (collaborative with Nelson Mandela Metropolitan University, South Africa, and Corus Research and Development). This involved diffraction strain scanning (ESRF experiments ME-197, ME-282, ME-992; ILL experiments 7-01-167, 7-01-196 and 1-01-8) and led (MN James) to a plenary lecture (1st International Conference on Fatigue Crack Paths, Parma, Italy 2003) and a keynote paper (2nd International Conference on Fatigue Crack Paths, Parma, Italy 2006). Collaborative work with Yates at the University of Sheffield on the interactions between machining, shot peening and fatigue in aircraft alloys also exploited synchrotron strain scanning to gain insight into optimal combinations of fabrication parameters for dynamic performance (experiment ME-748).

Over the next 5 years the mapping capability deriving from sophisticated modelling and visualisation will be linked with detailed knowledge of materials, defects and structural properties to advance understanding in topics like LMAC mechanisms in galvanised steel, stress engineering for optimum manufacturing and fatigue life prediction. The potential of synchrotron and neutron diffraction will be exploited to unlock advances in processing, reliability and integrity of structures and materials, building on the highly successful work described above.