The transport sector is currently facing global economic uncertainty, tough market competition, stringent EU emission and efficiency targets, increased vehicle occupant safety requirements, and pollution and safety scandals which have damaged its reputation. These factors require engineers to increasingly adopt the use of composite materials, to come up with cheaper, safer, and more environmentally friendly solutions. However, even if these materials enable the production of light energy-efficient vehicles, most carbon fibre composites are expensive, and thus the majority of their current applications are limited to the aerospace and motorsport industries. Furthermore, conventional composites have a high manufacturing carbon footprint, and they are typically non-recyclable at the end of life of the components. Natural fibre composites (NFCs) are now being used in the automotive industry, as a cheaper and more environmentally friendly option to conventional carbon fibre composites, albeit limited to non-safety critical components, due to their poorer mechanical performance. The TEMPEST research programme explored the possibility of using a novel NFC material offering improved mechanical performance (developed by partner organisation Bcomp) in safety-critical structural components. Furthermore, by collaborating with McLaren Racing, who have been developing composite crash structures for over two decades, the project aimed to advance on the current state-of-the-art in the fields of experimental and numerical crashworthiness, all the while trying to reduce the carbon footprint of such structures. The project also drew on the resources and experience of Instron's drop tower R&D department in the development of improved dynamic crush testing for composite materials. Furthermore, the FIA also contributed to the project, overseeing and guiding the development of the experimental and numerical work, with the aim of providing the motorsport and automotive industries with new data and proven methodologies for improving the design of composite crash structures.
The main project objectives were: a) to develop and standardise experimental characterisation techniques for obtaining the energy absorption of composite materials; b) to explore the use of sustainable flax fibre composite materials in crashworthiness applications; and c) to improve the accuracy and robustness of macro-scale numerical modelling tools for the design of better composite crash structures.
At the end of the project, the main outcomes were: a) significantly improved experimental setups for dynamic crush testing of various coupon geometries; b) a successful demonstration of the potential use of flax fibre composites in crash structures; and c) an objective geometry-dependent discretisation methodology that improves the accuracy and robustness of numerical predictions from Finite Element crash structure models.
