Lightweight Energy Absorbing Aluminium Structures for Transport (LEAAST)

Lightweight crash management systems are of increasing importance for most forms of ground transport. Automotive OEMs like JLR have advanced aluminium automotive body designs but still depend on steel for bumper beams and for rail applications steel based crash systems predominate. Constellium has developed considerably stronger extrusion alloys based on the AA6xxx alloy system that are fully recycling compatible with the sheet used for automotive structures and body panels. Brunel University has developed alloys and casting technologies that enable extrusions and castings to be combined in novel ways to produce a new generation of compact lightweight crash management systems. The envisaged work programme with include the high strength alloy being combined with casting alloys using overcasting techniques and the use of bonded and riveted joints to demonstrate the potential for both increased crash resistance and weight saving. The project will demonstrate and evaluate optimised designs for crash management systems for both automotive and rail transport.
The proposal aims to achieve a cost-effective material/manufacturing technology delivering a step-change in weight reduction for crash management systems for use in the automotive and rail sectors. We will design, manufacture & demonstrate lightweight aluminium systems based on the use of a novel high strength aluminium extrusion alloy that can replace the incumbent steel systems whilst providing at least a 25% weight reduction using alloys formulated from recycled end of life scrap. Utilising a novel overcasting technology that will eliminate the need for welding using casting alloys that are also based on recycled metal, we will also utilise the flow forming technology available in the UK for the first time to provided low waste near net shape manufacture of precision components for crash management systems. The project will involve the development, simulation & validation of novel architectures for both road & rail which radically exploit the new design freedoms afforded by the recent advances in high strength aluminium alloys, in overcasting & riv-bonding joining techniques & in novel casting & near net shape manufacturing methods. A second outcome will be the tangible steps taken towards a more sustainable, more UK-centric supply base & manufacturing capability in resource-efficient lightweight solutions through the leading partners (JLR & Constellium) in the Advanced Metal Casting Centre at Brunel University. The project consortium includes representatives from across the UK supply chain covering a range of industrial sectors.
Predominantly focusing on crash management systems for automotive & rail applications the technology, once proven can be easily transferred to other structural systems in chassis & body where steel structures can be replaced. Closing the recycling loop by the replacement of dissimilar alloys in the LCV body structures will increase the intrinsic value of the end of life vehicle as the body structure will be returned as a post-consumer scrap source either to the wrought sheet & extrusion producers (high value) or for the manufacture of further alloys with high recycled content of which the benefits were highlighted by the successful TSB REALCAR (TP/9/LCV/6/I/S0086E). Further dematerialisation will be achieved with the increased use of aluminium in LCVs & the use of lower cost, more recyclable alloys expanding the use of aluminium intensive vehicle structures from premium vehicle to more affordable & higher volume vehicle classes. Similarly, rail investment in lightweight rolling stock will follow similar strategies to automotive which will result in significant dematerialisation (weight reduction) of these presently steel intensive structures. Building on developments in the EPSRC supported TARF-LCV project supported under the TSB-LCIP through the inclusion of the EPSRC Centre for Innovative Manufacturing in Liquid Metal Engineering.

Use of aluminium crash management systems drops progressively with automotive vehicle class and major OEMs like Ford
and VW make no use of aluminium for crash management and aluminium systems are not used in rail applications today.
The opportunity is to provide significantly improved and affordable aluminium intensive crash management systems across
all the vehicle classes and to introduce an aluminium intensive solution for rail applications. Further, this novel technology
can be applied to suspension and chassis components where major future weight reduction opportunities arise. The market
is driven by stringent legislative requirements for carbon emissions and by EU led requirement for car manufacture with
95% ELV
recyclable materials. However OEMs will only embrace the use of aluminium alloys in such applications if it's cost
competitive with no sacrifice in performance or vehicle safety.
The use of high enrgy absorbing AA6xxx alloys in crash management systems is novel. Innoval and Constellium have
developed a new generation of alloys with strength properties significantly in excess of the alloys like AA6082 currently
used. Constellium have made patent applications based on the alloy composition in combination with a novel extrusion
processing technology that significantly reduces manufacturing costs. These developments can compete with steel based
systems across the automotive vehicle classes and in rail applications for the first time. Development of a novel net shape
assembly process by means of low and high pressure overcasting techniques will establish a new joining technology that
delivers a significant simplification in the manufacture of crash management systems. The combination of the novel
extrusion alloy with flow forming that is available in the UK through AFRC for the first time is innovative for the UK. To date
all work on the AA6xxx crash alloy has been based on the use of primary
metal. The project will provide the first opportunity to apply the Brunel melt conditioning technology for impurity tolerance
and/or impurity removal for the first time. The project will be able to take advantage of the EPSRC AMCC at Brunel that will
be opened at the end of 2014 and will take advantage of innovations from a number of earlier EPSRC and TSB supported
projects.