Aerostructural Efficiency of Damage Tolerant Composites via Optimised Fibre Placement

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.

Bath, Bristol and Airbus have a well established track record of successful collaboration with evidence of impact on business operations. The universities currently have ten jointly supervised composites PhDs under the Great Western Research alliance. Eight of these form the Airbus, Bristol, Bath STrategic Research Alliance in Composites Technology (ABBSTRACT) programme in which work is disseminated to a wider Airbus audience in quarterly seminars/reports. The aim of the proposed project will be to develop innovative UK design and manufacturing capability in order to maintain competitiveness and increase the share of UK-based manufacture of lightweight, high performance composite structures, particularly, but not exclusively, for the aerospace sector. Specifically, lighter structures with lower production costs for aircraft wings will be realised. This has significant societal impact because weight reduction will reduce operating cost, noting that the single aisle aircraft market (15,000 sales) is expected to be worth $1000 billion by 2025. Furthermore, reduced weight will reduce fossil fuel usage and emissions and help fulfil European ACARE 2020 goals. Specific beneficiaries are Airbus and GKN who will gain a significant competitive advantage through this technology for future generations of aircraft, although indirect benefit will extend to airline operators, passengers and the environment. Further beneficiaries are Bath and Bristol's long-term industrial partners, including Roll-Royce, GE Aviation, AgustaWestland and Vestas Wind Systems who will gain quick first-hand knowledge of the publicly disseminated results, via regular project meetings (and the annual Bristol composites conference). Other beneficiaries may include other structural applications that require lightweight, thin-walled solutions, covering, for example, land, sea and space transportation sectors as well as the lightweight building sector. The exploitable outputs of the project will be new design and manufacturing processes. These will be made available to industry as software routines, design guidelines, and in the form of reports giving results of experimental test programmes. The potential impact of outputs, including publications and demonstrators will be assessed during review meetings of the Project Board. All outputs (publication, web pages, presentations, etc.) will be made publicly available having ensured that the commercial advantage to Airbus and GKN is not compromised. Terms of engagement will be based on those of the existing Framework Agreement between Bath, Bristol and Airbus. Mechanisms for communication to wider beneficiaries include dissemination via conferences and international journals. Both PIs will be responsible for maximising and monitoring impact.