Manufacturing lightweight structures for the low carbon vehicles of tomorrow
Advanced lightweight materials play a significant role in reducing carbon emissions and improving fuel economy in the transport sector.
Although carbon and NOx emission reductions can be made by refining engine efficiency and performance, the final leap needs to be aided by innovation in materials and manufacturing processes that substantially reduce vehicle mass. It is estimated that to meet current emission reduction targets, as well as adopting cutting edge engine technology, vehicles will need to shed about 25% of their present mass.
However, the expense of developing and implementing the move to lightweight materials is currently a barrier to industry-wide take up. We are developing new products and manufacturing protocols to design and manufacture engineered-porosity structures that combine high-spec mechanical properties and low weight.
Lightweight structures can be achieved by reducing mass from the zones not subjected to the loads and stresses when in service, or by reinforcing those areas that are most exposed and at risk of failure by selectively introducing and orienting a second phase in the matrix, e.g. fibres or particles.
The resultant material is a porosity-tailored structure with selectively reinforced areas that outperforms its solid counterpart and at a fraction of the weight.
The novel materials are currently being developed for use in vehicle structural beams in partnership with companies that operate in the Automotive industry and its supply chain. Our collaboration is brought together based in the understanding that reaching the target the UK has committed to for CO2 emissions levels by 2025 will require a de-carbonisation of the transport industries.
The technology applied in this project is based on our research using sonication of polymeric foams (carbon fibre-reinforced polyurethane) whose porosity can be graded to obtain an optimised load-bearing structure: creating low density in the areas where stiffness is not needed, and moving mass, therefore obtaining high density in areas where it is, and with the reinforcement of carbon fibres to extend the range of its high performance. This is done by irradiating acoustic waves to a forming viscoelastic matrix in which the size of the bubbles (once solidified, pores) can be modified and their location controlled. In addition to that, reinforcement through aligned fibres to further engineer load-bearing sections will be integrated in our research.
We are developing a ‘factory-in-a-box’ technology for the production of vehicle structural components that are multifunctional, exhibit stiffness in the chassis and provide damping regions that absorb impact energy, are low-cost and net-shape to require minimal tooling permitting a bespoke design.
The multifunctionality is achieved by coupling features thanks to the gradation within the structure which grants enhanced coexisting thermal, shock-absorbent, controlled-diffusing and/or vibration damping properties. These lightweight multifunctional structures are unmatched by those fabricated by conventional production methods.
A list of relevant publications can be found in the Loughborough University repository
Dr Carmen Torres-Sanchez - Reader in Multifunctional Materials Manufacturing and Executive Director, Centre for Doctoral Training in Embedded Intelligence
“Lightweight composite components are the next pit-stop in the challenge of reducing mass and therefore curb emissions, to improve fuel economy in the vehicle industry without sacrificing performance”