I am an Associate Professor at the University of Nottingham, where my research for the past 20 years has focussed on material and process developments for fibre reinforced polymer composites. I have particular interests in discontinuous fibre composites, which are suitable for producing sustainable, high volume components within the automotive sector. My research focusses on the development of automated manufacturing processes, which require an understanding of the underlying material science in order to offer technologies that are cost-competitive against traditional engineering materials. My work typically covers process development, process simulation and optimisation, which has significant industrial relevance.
The impact of my research has been far-reaching, reducing the mass and improving both the performance and economy of passenger vehicles. I co-developed the Directed Carbon Fibre Preforming (DCFP) process, in collaboration with Aston Martin Lagonda Ltd, which is a robotic chop and spray fibre delivery system for producing low cost, geometrically complex fibre preforms. I was responsible for developing a laboratory-scale manufacturing rig and a corresponding digital model to optimise the mesoscale material architecture, in order to minimise stochastic variability. This process made a significant contribution to the economic competitiveness of Aston Martin Lagonda, who employed the technique for the production of two structural components for the 12MY DBS, 12MY Virage, 13MY DB9 and Vanquish models. For the DBS model alone, 3,300 cars were sold in 42 countries at around £180,000 each, which equates to revenue of £594M. These two carbon fibre parts represented a weight saving of 52% and 44% compared to equivalent aluminium parts, with over 23 tonnes of material reaching the market. This work has received outstanding peer reviews, having featured as an impact case study in the 2014 REF exercise and has been disseminated in 16 journal publications to date (which have been collectively cited 514 times).
The thermoforming of complex composite parts has traditionally been difficult to automate, relies on labour intensive processes and generates large amounts of material waste (approximately 40% of fabric broad-goods). My most recent research has resulted in a simulation tool to optimise the manufacturing capability of continuous fibre preforms using an automated double diaphragm forming process. The simulation tool has been successfully used to perform virtual manufacturing studies to demonstrate that deep-draw parts can be produced with complex double curvature using low forming pressures. This has confirmed to a UK automotive OEM that automated forming can be achieved using low cost single-sided tooling for critical structural applications, underpinning the production of the next generation of McLaren carbon fibre supercar chassis in the UK. Project partner Hexcel Reinforcements Ltd (formerly Formax UK) has also developed new forming technologies from this research, reducing overall fabric waste to 5%. The successful outcomes from this project have helped to secure the future of Hexcel's R&T department in the East Midlands and added a significant new capability for Hexcel Corporation. This work has been disseminated in 11 journal papers to date, with the highest cited manuscript investigating the initiation and evolution of wrinkles during the fabric forming process.
My research track record and wide industrial network has led to many interesting consultancy projects with large OEMs and members of the composites supply chain, providing further opportunities for impact and knowledge exchange. Projects have ranged from producing composite demonstrator components for Airbus UK, Audi GmbH and Bentley Motors Ltd, to roadmaps and life-cycle assessments for Saudi Aramco and Nissan Motors respectively. One of the most noteworthy projects was working with the World Champion Freestyle Kayaker, James Reeves, to design and manufacture a high performance kayak using the DCFP process.
I am currently the manager of the EPSRC Future Composites Manufacturing Research Hub, which is the largest single investment for fundamental research (TRL1-3) in composites manufacturing in the UK. I manage a funding portfolio of over £10m, working directly with 15 UK universities, 4 High Value Manufacturing Catapult centres and 43 industrial partners. The role requires exceptional leadership and organisational skills and has helped me to develop my personal network, raising my national profile as a leading researcher in composites engineering. Consequently, I am a member of the Composites Leadership Forum's Technology Working Group, responsible for delivery of the UK Composites strategy, reporting to the Department for Business, Energy and Industrial Strategy (BEIS). I am also an active member of the Society for the Advancement of Material and Process Engineering, chairing the Young Engineer and Student (YES) committee, which promotes collaboration, provides social engagement and shares expertise with the next generation of leaders within the composites sector. I am responsible for organising a series of annual events, including a student seminar and a design-and-make challenge to promote interest in composites to our young members.
There is a national skills shortage in the UK composites sector, so raising awareness of science and engineering of composite materials to the wider community is important to produce future talent. I have engaged in a number of outreach activities at secondary school level, including British Science Week and the Festival of Science and Curiosity in Nottingham, to inspire future generations to engage in STEM subjects. I also offer funded 10-week summer placements to final year undergraduates who are contemplating a postgraduate position, to attract suitable students for PhD and EngD positions in composites manufacturing. I teach the undergraduate Fibre Reinforced Composites Engineering module at the University of Nottingham and use my own research experiences to ensure the lecture content is current and industrially relevant, raising awareness of composite materials to younger members of the academic community. I have recently completed editing a text book for Elsevier on the 'Design and Manufacture of Structural Composites', which outlines the manufacturing challenges associated with fibre reinforced polymers for high-performance applications. The book includes contributions from leading experts in the field and provides an essential reference resource for members of industry, materials researchers, science and engineering students and educators who are working in the field of polymer matrix composites.
Module convenor for Fibre Reinforced Composites Engineering - MMME3054
Design tutor for Aerospace Design and Materials - MMME1049
Design tutor for Aerospace Design and Manufacture - MMME2033
Made Smarter Innovation - Materials Made Smarter Research Centre, EPSRC EP/V061798/1 (£400k, PI) - 2021-2025
CHEN, S., MCGREGOR, O. P. L., ENDRUWEIT, A., ELSMORE, M. T., DE FOCATIIS, D. S. A., HARPER, L. T. and WARRIOR, N. A., 2017. Double diaphragm forming simulation for complex composite structures: Composites Part A: Applied Science and Manufacturing Composites Part A: Applied Science and Manufacturing. 95, 346-358 HARPER, L. T., QIAN, C. C., LUCHOO, R. and WARRIOR, N. A., 2017. 3D geometric modelling of discontinuous fibre composites using a force-directed algorithm JOURNAL OF COMPOSITE MATERIALS. 51(17), 2389-2406
CORBRIDGE, D. M., HARPER, L. T., DE FOCATIIS, D. S. A. and WARRIOR, N. A., 2017. Compression moulding of composites with hybrid fibre architectures: Composites Part A: Applied Science and Manufacturing Composites Part A: Applied Science and Manufacturing. 95, 87-99