Whilst the basic advantages of composite laminates, such as carbon fibre-reinforced plastic, are well proven, they are often compromised by high cost, long development time and poor quality due to multiple defects, particularly in complex parts such as those found in aerospace applications. Within the aerospace industry, where safety is paramount, design changes require expensive programmes of empirical testing over a variety of length scales, the so-called "test pyramid". An important objective of this complex engineering system is to minimize the probability of failing the certification test. Modelling technologies and testing at various stages of development are all orchestrated toward this objective, which has been heuristically developed over the last decades without a clear understanding of how each player contributes to uncertainty reduction. This project will engage a multidisciplinary team of engineers and mathematicians to develop novel mathematical modelling tools to address this issue. An embedded university-industry partnership will focus effort on creation of new capability with underlying fundamental research to reduce design-to-manufacture time and increase quality in airframe and aero-engine manufacture, critically important to the international standing of the UK aerospace sector. We will systematically develop stochastic models that integrate uncertainties from simulations and empirical testing (at different stages of the test pyramid) and quantify their propagation through the system to provide effective and reliable quality control for high-quality carbon fibre manufacture. New and fully-validated, laminate designs will be developed that challenge the inherent conservatism and the expensive industry standard which predominantly uses empirical testing for structural integrity certification. A central theme to the project is the complex interaction of multiple scales within the structural hierarchy of an aircraft component. Interaction over all the scales strongly influences each of the three research areas addressed within this programme. Recently gained expertise in the modelling of folding in layered geological structures will be exploited to study the physically analogous formation of defects during automated manufacture of laminated parts. Multiscale structural performance models will draw upon novel numerical upscaling techniques to predict the strength of large aerospace components containing microscale internal defects. Novel probabilistic uncertainty quantification tools, such as multilevel Monte Carlo and multilevel Monte Carlo Markov Chain, will be brought to bear in performance analyses of entire sub-components. The data for these models will be inferred directly from images obtained using Computational X-ray Tomography (CT). Manufacturing practices will be informed by seconding team members to GKN Aerospace, located at the National Composites Centre, to explore the interaction between the technical and business objectives of the industry, assisting researchers in the use of the new modelling tools, and in the selection of optimal manufacturing solutions. Target components will be wing spars, skin-stringer panels, and engine fan blades. The development and application of the novel stochastic methods for failure prediction will be undertaken with expert guidance of visiting researchers from the University of Florida and Lawrence Livermore National Laboratory, CA. Our vision is to enable a greater than 50% reduction in design-to-manufacture time whilst ensuring predictable product improvement, amounting to significant (>10%) component weight saving.

Commercial aviation contributes 2-3 % to global carbon emissions and the International Energy Agency has predicted that this will triple within the next three decades if no action is taken. In the UK the current contribution is 10% due to high levels of international traffic, and this could reach 40% by 2050 without action. The UK government has therefore set out an ambitious target to demonstrate a zero-carbon emission aircraft by 2030 within the UK Hydrogen and Net Zero Strategies. The design and manufacture of aircraft has previously focused on incrementally improving structural efficiency and productivity of the semi-monocoque parts which make up the wing, fuselage and tail, with a degree of linkage between fuel tank boundaries and structural function. However, next-generation aircraft will require energy storage using fully integrated structures and materials whilst accounting for environmental impact. GKN is the leading global Tier-one supplier of parts for most of the world's aircraft manufacturers. The University of Bath has world-leading expertise in the analysis, design and manufacture of composite parts, as well as in the creation of functional materials and their use for sustainable hydrogen energy. GKN and Bath have a track record of collaboration via a Royal Academy of Engineering Research Chair, eighteen joint PhDs and as formal partner in four EPSRC projects including an ongoing Programme Grant (CerTest, EP/S017038/1). Previous research has focussed in the areas of structural composites and manufacture, with most collaboration within Bath's Materials and Structures (MAST) Centre. The ZENITH Prosperity Partnership arises from GKN's ambition to realise zero-emission aircraft in the 2030-40 timeframe and the University of Bath identifying sustainability as a priority research theme. It addresses fundamental challenges within the two major research themes of Hydrogen Storage and Sustainable Structures. It brings together a highly skilled, multidisciplinary team of scientists and engineers from MAST, the Departments of Chemical Engineering (hydrogen storage, heat transfer), Chemistry (sustainable polymers, porous materials) and Mathematical Sciences (statistical modelling). It will exploit links with leading research institutes and centres at Bath, including the Centre for Sustainable and Circular Technologies (CSCT), the Institute for Advanced Propulsion Systems (IAAPS) and the planned UKRI Centre of Excellence for Hydrogen Research. ZENITH will establish GKN and UK academia as world leaders in manufacture of parts for zero emission aircraft, positioning the UK at the forefront of this rapidly developing market.

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The proposed project will create new capability to improve the structural efficiency of laminated carbon fibre composites. It will reduce weight and production cost by at least 10% (and possibly up to 30%) compared with existing stiffened panels made from pre-impregnated material. The new methods will facilitate the development of game-changing technology. The key innovation of the project will be to exploit state-of-the-art manufacturing, Variable Angle Tow (VAT) placement (where stiff carbon fibres are steered along curves to maximize structural performance). Ongoing studies suggest that such savings are achievable for standard test specimens (coupons) but new understanding is required to fully characterise structural and material behaviour from the full component level down to individual lamina and their interfaces. The entire structural system including material, geometrical and manufacturing parameters will be optimised. The extra design freedoms, created by curved fibre trajectories, provide scope for pushing back the envelope of structural efficiency. The academic team provide a unique capability to fulfil this vision. They have a proven track record in manufacture, modelling and design of composite materials and structures and have clear routes to exploitation via a pivotal industrial base. Their novel damage tolerance modelling techniques indicate that large improvements in material efficiency can be achieved if critical positions of delamination damage are tailored via through-thickness laminate optimisation. The team's preliminary VAT results indicate the prospect of developing buckle-free structures, reducing the need for stiffeners, with associated substantial cost and weight savings. Moreover, the specific manufacturing capability to produce variable angle fibres is unique to the UK, having been modified from an embroidery machine, using dry fibres rather than pre-impregnated material. Airbus and GKN will support the project with 290k of direct funding.

If demand for production of next-generation, short-range commercial aircraft is to be profitably met, current methods for composite airframe manufacture must achieve significant increases in material deposition rates at reduced cost. However, improved rates cannot come at the expense of safety or increased airframe mass. This project will enable a fourfold increase in productivity by establishing novel manufacturing techniques that speed up deposition of stiffness tailored material. New continuum mechanics-based forming models will ensure delivery of better products by minimising occurrence of manufacturing defects. In a parallel stream of activity, new methodologies for analysis and design of composite structures in which the ply angle and thickness of fibre-reinforcement is spatially tailored, both continuously and discretely, will reduce the need for stiffening, leading to significant savings in structural mass (by up to 30%) and manufacturing cost (by up to 20%). Potential structural integrity and damage tolerance issues, such as transition in fibre angle and tapering of laminate thickness from one discrete angle to another, will be addressed. The project will engage a multidisciplinary team of engineers and applied mathematicians to develop novel manufacturing and modelling techniques. An embedded university-industry partnership will focus on the creation of new manufacturing and analysis capabilities, supported by fundamental research. Academics at Bath and Exeter will partner with the National Composites Centre and with industrial collaborators that span the airframe supply chain. The project will enable production of high performance composite components at rates suitable for the next generation of short-range aircraft. There are also opportunities for impact in the wider composites manufacturing industry, including automotive and energy sectors.