New UK aerospace project set to challenge certification norms

A new project led by the University of Southampton will explore the use of composites in aerostructures and seek to highlight the limitations in current certification procedures.

certification
(Credit: Airbus/Bengt Lange)

Backed by an EPSRC grant of £6.9m, the research will focus on more structurally efficient and lightweight airframes. In doing so, the team hopes to challenge existing aerospace norms and seek step-changes that the regimented certification process may be preventing. By driving reduced weight, cost and development cycles, the researchers are aiming to lay the foundations for the aviation of the future, where fuel efficiency and electric/hybrid propulsion are expected to come to the fore.

“This funding is essential to enable continued growth of the UK aerospace industry and take economic benefits from the opportunities inherent in the move towards more sustainable aviation, as it fills a knowledge gap, where there is no equivalent capability in the UK or internationally,” said lead researcher Ole Thomsen, professor of structures and materials at the University of Southampton.

“Using world-class expertise, this programme grant from EPSRC will enhance the UK position in the technical revolution that embraces new materials and processes, by addressing an urgent need in aerostructures design.”

Titled ‘Certification for Design: Reshaping the Testing Pyramid (CerTest)’, the research programme will take a completely new approach to component development. The current certification regime takes a so-called ‘building block’ or ‘testing pyramid’ approach, examining components at (i) Coupon, (ii) Structural detail, (iii) Component, and (iv) Sub-structure or full structure level. As the cost and complexity of testing increases through the levels, the vast majority of testing takes place at the ‘Coupon’ stage. The underlying assumption is that the material properties derived from lower levels can be used to extrapolate the requirements for higher component complexity. But the researchers claim this is not necessarily the case.

“At best, this leads to conservative, over-constrained design,” according to the grant application. “At worst, there is risk that potentially unsafe scenarios can develop where combinations of weakening events cascade into premature failure.”

“There is increasing awareness that, in its current form, the ‘building block’ approach prevents the innovative use of composites, and consequently that the potential benefits of using advanced composites in terms of lightweighting and efficiency cannot be fully realised under current certification and regulatory procedures.”

In pursuit of its goals, the project will implement virtual testing and advanced data-rich experimentation of aerostructure components and substructures. Academic project partners include the University of Bristol, University of Bath and the University of Exeter, while industry support comes via Airbus, BAE Systems, Rolls-Royce, GKN Aerospace, the Alan Turing Institute, CFMS and the National Composites Centre.

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