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Research at Portsmouth has had a major impact on risk reduction, improved service life and reduced inspection/maintenance costs of safety critical and expensive fan and compressor components in military and civil aero-engines, as demonstrated particularly by the Liftfan Blisk manufactured by Rolls-Royce.
The research outcomes have also impacted on the specification of design stress levels by Rolls-Royce and MOD for aerofoils susceptible to FOD, enabling damage size inspection limits to be established at higher and more economic levels. The research has also provided increased confidence in the application of weld-repair of FOD and of surface treatment using Laser Shock Peening against FOD.
We have optimised aerospace structural designs and assessment methods through development and application of hybrid residual stress characterisation techniques. Our research results on bonded crack retarders have redirected industry development programmes on hybrid metal laminate material systems and been used to evaluate reinforced structural concepts for US Air Force wing and fuselage applications. Methods to assess and mitigate maintenance-induced damage have been developed and implemented based on our research. Our contour measurement technology has been transferred to the US Air Force, which now has the capability to perform measurements in-house and support work with both NASA and the US Navy.
Research in materials characterisation at Swansea University has produced a deeper understanding of the mechanical behaviour of proprietary engine components, and the potential improvements that can be made. The research has provided a critical technological contribution to the manufacture of efficient and robust gas turbine engines, fundamentally supporting the declaration of safe working lives for critical rotating components, contributing to a significant reduction in specific fuel consumption, and enabling Rolls-Royce to maintain a 40% share of the global civil aviation market. The research has led to the creation of a profitable spin-out company (Swansea Materials Research & Testing Ltd - SMaRT) with an initial annual turnover of £1m.
Rolls-Royce has been able to reduce manufacturing scrap rates significantly, better control the single crystal growth process for nickel superalloy blades and more confidently understand production issues in Ti blades. The lower bound saving for the Imperial contribution to the work is estimated at £100M p.a. This has contributed to the production of a jet engine with better fuel efficiency, increased cost effectiveness due to lower scrap rate and improved time on wing for fleets in service.
Jet engine modifications account for over half the fuel efficiency improvements in modern aircraft, with the industry accounting for a large share of UK visible exports. Improvements in gas turbine technology offer jet fuel (cost and CO2) savings and support UK employment. Titanium alloys in the cooler sections and nickel alloys in the hot sections are the subject of this case study.
The engines consist of Ti or Ni alloy discs attached to a series of shafts which are turned by aerofoils (blades) in the gas stream. Incoming air is accelerated by the fan section then compressed, mixed with fuel and burned, with the energy then being extracted by the turbine. Turbine blades operate in a gas stream at 1800+ K, 200 K greater than the alloy melting point, and extract up to 700 kW per blade to power the fan and compressor. Each disc holds around 60 blades, with around 9 turbine stages in a large engine. In titanium, failure of a fan blade or multiple blades is extremely costly (£5M per event) and of course poses safety issues. Research in the Department has focussed on a) predicting the microstructure of nickel superalloys and b) understanding defect formation in titanium and superalloys.
Impact on industry, academia and government institutions from engineering materials research in the Mechanical Engineering department has been delivered through it directly leading to UK, USA and International Standards and Codes relating to three themes:
The results of the research of staff in this unit have led directly to UK, US and International Standards and Codes: ASTM Standards E1457-07 (2012) and E2760-10 (2012); R5 EDF Energy Code of Practice (2012); BS 7910 (2013); ISO 25217 (2009); ISO CD 15114 (2011) and ISO 13477 (2008). These documents all cite peer-reviewed publications by staff from this unit. These Standards and Codes are now the basis of fracture-mechanics methodologies used by leading engineering companies like Airbus, EDF, E.ON, GKN, Rolls-Royce and Vestas, whose commercial success depends upon technological leadership. In this way our research has led to savings by UK industry of many millions of pounds, as detailed in Section 4.
Long-term fixation integrity is a critical issue in joint replacement surgery that affects both quality of life of patients and the economy. The unique comprehensive study of long-term acetabular cement fixation carried out at the University of Portsmouth has significantly informed orthopaedic surgeons and impacted on their surgical practice. In addition, research on a commercial hydrogel implant TRUFIT has informed clinical and commercial decisions on the use of the implant for load bearing applications, which has led to the withdrawal of the implant from the global market.
Research carried out by Cardiff University on the causes of maritime fatigue was instrumental in increasing understanding of contributing factors such as long working hours, and the inadequacy of current reporting systems. Because 90% of goods are transported by sea, fatigue influences at the individual and community level, as well as resulting in significant financial penalties for companies when accidents occur. Cardiff research has led to significant changes across industry and government in (a) personal awareness/management, such as improved safety training and (b) new international legislation and company policy aimed at reducing fatigue and improving health and safety at sea.
Wide Chord Fan Blades provide a key competitive advantage for Rolls-Royce's £8.6bn aero-engine business employing 1500 staff. In service, blades experience massive loads and high-frequency vibration, creating the potential for failure. In response to blade-off events on the Trent™ 800 engine, Rolls-Royce (RR) urgently needed a means of inhibiting fatigue crack growth, and selected laser shock peening (LSP). Research in the UoA, elucidating the mechanism and outcomes of LSP, provided critical scientific underpinning for its introduction into the production process for the Trent™ 800 and, subsequently, other engines. Further the UoA now provides manufacturing process QA. Orders for the new Trent™ XWB engine, relying on LSP, exceed £60bn, with partners The Metal Improvement Company establishing dedicated LSP treatment facilities for RR in the UK (with 30 employees) and Singapore.
Research into a number of different aspects of rubber has fed into a series of extremely successful collaborations between Queen Mary and a large number of industrial partners. This has led to significant economic impacts, ranging from enhancing the performance of teams in the multi-billion dollar sport of Formula 1 Racing, to helping develop new UK designed and manufactured radial tyres for large civil aircraft. Rubber research has been undertaken continuously at QMUL for over five decades. Prof. James Busfield has led the activity since 1994, working with more than 30 major industrial collaborators, including Bridgestone, Dunlop, Red Bull Racing F1 and TARRC, who have applied our research and employed our researchers to achieve commercial and competitive advantage.
Research on the growth of gallium nitride (GaN) light-emitting diode (LED) structures has led to the creation of two spin-out businesses (subsequently sold), has assisted Forge Europa Ltd in expanding its sales of LED-lighting products, has helped AIXTRON to achieve sales of related GaN-growth equipment [text removed for publication], & has enabled Plessey Semiconductors Ltd to manufacture the world's first commercially available LEDs on 6-inch Si (& the first LEDs to be manufactured in the UK).