The Lightweight Metal Composite Hybrid (LiMeCH) project saw the creation of a lighter alternative to the tubular steel stabiliser bar currently used for suspension units in trucks and trains. Working with Sheffield-based Tinsley Bridge and Rotheram’s Performance Engineered Solutions, the AMRC Composite Centre helped develop a solution that is that is 30 per cent lighter than bars that are currently on the market.
“Lightweighting is top of the agenda for our customers,” said Russell Crow, director of engineering at Tinsley Bridge. “That is even more so when they are looking at alternative propulsion systems, such as electric drive trains and alternative fuels, because every gram they can save offsets the additional mass they have to carry for the batteries or hydrogen fuel tank.”
Carbon fibre composites are not yet widely used in the volume automotive sector for functional parts such as suspension systems, where the industry standard is a steel tube welded to metallic end fittings. Replacing the steel with lighter materials can improve fuel efficiency, helping operators meet new emissions regulations. Composite materials are also less affected by fatigue so their use can deliver increased reliability without compromising performance.
Tinsley Bridge had previously worked with the AMRC to develop a metallic and carbon fibre reinforced plastic (CFRP) hybrid composite roll bar on a previous project called Lightweight Composite Suspension Components (LiCoSuCo). According to Craig Atkins, research engineer at the AMRC Composite Centre, although that project made advances in the areas of volume composite manufacture, metallic arm production and bonding, it created other issues and the team had to develop solutions.
“We took outcomes from LiCoSuCo that didn’t succeed, in particular with the integrity of the bonded joint between the metallic and carbon fibre,” he said. “The continued LiMeCH project builds upon the results of the previous project and continues the collaboration and research.”
The AMRC’s Composite Centre produced four anti-roll bar prototypes using its MF Tech filament winding system in which filaments of carbon, impregnated with resin, are wound onto a rotating mandrel to form a desired shape. PES penetratively inspected the inside of the bar using CT scanning technology, then used an in-house light scanning system to visually inspect the parts. According to Atkins, the project’s success has implications far beyond heavy industry.
“The ARBs we prototyped are designed for trucks, trains and military vehicles, but it can be scaled-down - there is no reason why this technology can’t be applied to electric vehicles (EVs) and smaller vans used by courier services,” said Atkins.
“As the automotive industry moves towards greater electrification and lighter weight parts, there is ever greater focus on moving away from wholly metallic components. Finding a way to bond metallics to composites and reduce a component's weight by almost a third is a significant step along the road to net zero.”