Metal Composite Hybrids for Lightweighting

Reduction of emissions requires weight reduction in vehicle components regardless of whether these emissions occur at the tailpipe or at the power station. Weight reduction also increases the distance over which a vehicle can travel without refueling or recharging the battery; or, allowing for a greater payload over an identical distance. It is widely recognised that composites are the best technical solution for lightweighting but final product cost is limiting their use. This project will develop metal-composite hybrids so that composite parts can be manufactured in simple shapes using highly automated & quick manufacturing processes. These can then be assembled using metallic connecting elements. A key feature of the work is to examine the metal-composite bond to ensure that it can endure all the conditions it may be subjected to during the life of the vehicle, including impact damage, vibration and the effects of weather conditions on the part. A case study focusing on an anti-roll bar (ARB) for a 7.5 tonne front axle for a heavy duty goods vehicle will provide the means to prove the concept. Currently, ARBs are manufactured using solid steel bars and bent into shape. Previous studies showed that by making the ARB from a hollow composite tube with aluminium ends saved 65% of the mass of the part, with this scale of saving achievable on every axle of an HGV. A novel bond between the metal and composite was developed and during testing performed well under cyclic loading, with the aluminium arm rather than the composite tube or joint failing. This was unexpected, so more work is required to develop the hybrid system further. As the earlier study did not consider impact events or environmental effects, the scope of this project has been widened to include these eventualities. The project will develop a computer simulation of the materials and suspension system, including all loading cases the ARB would be exposed to during its lifetime, importantly, including fatigue. This is essential so that designs for other components and applications can be studied using computer simulation without having to manufacture every new design under consideration. This reduces the number of costly trial and error experiments required, shortening the time in which the new technology can be exploited and applied in other areas.