Next Generation Fibre-Reinforced Composites: a Full Scale Redesign for Compression

Lead Research Organisation: Imperial College London
Department Name: Materials

Abstract

High performance fibre-reinforced polymer composites are the current state-of-the-art for lightweight structures and their use is rising exponentially in a wide range of applications from aerospace to sporting goods. They offer outstanding mechanical properties: high strength and stiffness, low weight, and low susceptibility to fatigue and corrosion. The use of high strength, high stiffness materials in fibre form mitigates the tendency for premature brittle failure, enables components to be formed at low or moderate temperatures, and enables anisotropic designs to target the primary load-carrying demands. Fibres are particularly efficient in uniaxial tension but, under compression, composites suffer a range of failures typically associated with fibre micro-buckling or kinking, linked to matrix or interfacial issues; these mechanisms couple in a complicated way at a variety of physical lengthscales. Often, these types of failure determine the practical usage of composites and set design limits well below the expected intrinsic performance of the constituent fibres. On the other hand, new constituents and processes are becoming available that enable the directed assembly of composite structures, controlled across a much wider range of lengthscales than previously possible. In principle, then, composite materials should be redesigned to take advantage of these opportunities to supress or redirect the failure process in compression. Natural materials, such as wood and bone, are fully hierarchical, with precise structural features resolved at every possible magnification. Artificial composites lack this dexterity but can exploit intrinsically superior constituents. The increasing ability to visualise, calculate, and control structures, including with quantitative precision, will allow a new generation of composite materials to be developed. The ambition is to realise the full intrinsic potential of the fibres by designing such hierarchical systems for compression, from first principles, exploiting the latest developments in materials, processing, characterisation, and modelling of mechanistic processes.

This programme focusses on the challenge of improving the absolute performance of composites in compression, both to address practical limitations of current materials, and as a demonstration of the value of quantitative hierarchical materials design. Tools and materials developed during this programme will be useful in a range of other contexts. The work will develop and embed structure at every lengthscale from the molecules of the matrix, to the lay-up of final components, using new constituents and new architectures, designed with a new analytical framework. The programme will benefit from a highly creative and interdisciplinary approach amongst the core project term, amplified by contributions from leading international advisors and collaborators. An extensive group of industrial partners will contribute to the project, and help to develop the outputs, building on concept demonstrators designed during the programme. The scientific and technical results will be widely disseminated nationally and internationally, helping to ensure UK leadership in this key field.

Planned Impact

NextCOMP will provide the scientific basis and fundamental methodologies to overcome the limitations of current composites; by providing innovative routes to improve critical performance parameters. As a result, the UK will gain a decisive advantage in the global marketplace. The research impacts directly on academia, industry, and the High Value Manufacturing Catapult centres including the National Composites Centre and Centre for Process Innovation.
Companies working on established composite applications, including aerospace, offshore, wind turbines, and high performance sports, will gain access to new technology, either through directly licensing intellectual property developed during the programme, or through subsequent co-development projects, facilitated by the technology transfer teams at the two universities. Industrial partners will gain new capabilities allowing them to develop new products, leading to a competitive advantage, and ultimately, UK wealth creation. In addition, through commercialisation activities, the academic institutions will benefit from additional revenue that they invest to bring forward other new technologies. The UK is home to a number of major composites companies, who maintain their world-leading position, by embracing opportunities for innovation. Several such companies will play an active role in the programme grant, helping to build a UK research network in the emerging field of hierarchical composites. This grouping will foster future collaborations, encouraging UK R&D efforts, as well as attracting inward international investment.

Manufacturing companies, for example, in civil engineering, the automotive and chemical industries, who do not routinely use composites, may begin to use new, higher performance materials, enabled by less stringent design limits, and new design tools. The UK's internationally-recognised industrial design community will thus acquire a new capability to create further innovative products. At the same time, the extended use of composite materials will engage fresh academic interest, in fields ranging from chemistry to mechanical engineering, that will support the uptake and development of new designs and applications.

By developing new composite constituents and guidelines for their refinement in different contexts, the programme will support the development of an expanded UK materials supply chain for composites. Although the composite sector is predicted to expand rapidly, most of the added value is expected to lie with the materials supply, an area in which the UK lags. New materials solutions provide an opportunity to re-establish a lead in the market. The expansion is predicted to create a severe skills shortage, and the development of a high profile project will directly train a cohort of highly networked, skilled individuals, as well as motivate wider recruitment.

More generally, society will benefit from the emergent hierarchical composites that provide improved performance, safety and environmental sustainability in a variety of contexts. Associated weight reductions will offer improved fuel efficiency or range in transport applications, while wind turbines will be more structurally efficient and benefit from reduced maintenance requirements, particularly offshore. Some embodiments may enable direct recycling or reuse, a long-term composite goal. The program is aligned with stated UK objectives to realign the economy towards advanced manufacturing. It provides an opportunity to highlight the contribution of Science and Engineering towards these goals, both with the public and within government. Engagement with the general public through festivals, exhibitions, and online, together with educational activities in or with schools will advance the STEM agenda and help to develop the UK skills base.

Publications

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