Aerostructural Efficiency of Damage Tolerant Composites via Optimised Fibre Placement

Lead Research Organisation: University of Bath
Department Name: Mechanical Engineering


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.

Planned Impact

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.


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Description We discovered that about 30% weight-saving can be achieved if carbon fibres are steered to increase stiffness and thickness near the stiffened boundaries of a wing skin.
Exploitation Route The findings are in part the basis for a new EPSRC project ADAPT (EP/N024354/1) "Analysis and Design for Accelerated Production of Tailored composites". This will provide Bath with £691k (and Exeter with £422k) to work on the creation of unique continuum models for manufacturing processes and new analysis-driven design principles for aerospace composites. The project is collaborative with with GKN, Airbus, the National Composites Centre and (material supplier) Chomarat. It will commence in Q3 of 2016 and is due to finish in Q1 of 2020.
Sectors Aerospace, Defence and Marine,Transport

Title Damage resistance and damage tolerance of hybrid carbon-glass laminates 
Description Data relates to the damage resistance and damage tolerance of hybrid carbon-glass laminates. Impact data includes time histories for deflection, energy and force, and C-scan data of impact damage coupons. Raw CT data of impact damaged coupons is available for specific coupons. Compression after impact data includes strain gauge and DIC videos. 
Type Of Material Database/Collection of data 
Year Produced 2015 
Provided To Others? Yes  
Description GKN & Royal Academy of Engineering Research Chair 
Organisation GKN
Department GKN Aerospace
Country United Kingdom 
Sector Private 
PI Contribution Bi-monthly research meetings; reports; papers; software support; data
Collaborator Contribution Bi-monthly research meetings; data; supply of material; industrial expertise
Impact Over 10 PhD studentships; 50 papers; over £5M third party funding
Start Year 2011