Aluminium remains vital for automotive lightweighting

Delegates at the Future Automotive Body Structures seminar at the Heritage Motor Centre in Gaydon, Warwickshire, found that aluminium still has a surprisingly prominent role. Rachel Lawler reports.

Fifty per cent of all the patents filed in 1896 were related to bicycles. That’s more than 14,000 new inventions related to bikes in one year alone.

Of course we’re now living in a different world, a world where the car is king, but the automotive industry could learn a lot from the two-wheeled vehicle.

Bob Mustard, Managing Director at Stalcom Automotive Technologies Ltd, in Worcestershire UK, considered the impact aluminium had on the bicycle industry and wondered if the material could have a similar affect on the modern car. For him, aluminium was a better direction than some other alternatives. ‘I’m one of the few people that does not get excited about carbon fibre parts,’ he said.

Keynote speaker, Mark White, Chief Engineer at Jaguar Land Rover’s Complete Body Business Unit, located in Warwickshire in the UK, echoed his thoughts. Although White noted the reduced weight of carbon fibre composites compared to aluminium, the manufacturing process needed to create them concerned him. ‘Ultimately, it’s all about CO2 efficiency,’ he said, and with a energyintensive process needed to create them, carbon fibre composites don’t make the grade.

Ajay Kapadia, Senior Leader at the Materials KTN, agreed, noting that carbon fibre composites currently cost five times more than their metallic equivalents. ‘It is unlikely that the cost of carbon fibre will significantly decrease,’ he said.

White demonstrated the improved efficiency of the latest Range Rover and Range Rover Sport models – built using aluminium body structures. With 50% of a car’s weight tied up in these parts, material selection makes a big difference to fuel consumption. ‘We have taken a 2,000kg car and reduced its weight to 1,500kg,’ he claimed. Unlike carbon-fibre, aluminium frames can also be painted using existing equipment and therefore, greatly reducing the cost, although he didn’t rule out using composites in future models. ‘There’s still a lot of work to be done in composites but right now, from a cost and weight perspective, [carbon fibre composites] are just not there yet,’ he explained.

However, White did admit that there is ‘no silver bullet’ when it comes to reducing the weight of cars, and aluminium was not the perfect solution. ‘It is still more expensive to make an aluminium car than a steel car. But we can produce an aluminium car in fewer hours,’ he explained, adding that the company was looking to offset the increased material costs with reduced production time.

The common belief that aluminium cars do not perform as well as steel models is a myth, according to White. He believes that these cars are just as safe as heavier models, and their reduced weight lowers the impact of crashes and suggested that aluminium absorbs more energy per kilo than steel. He also reminded delegates of the rigorous testing all cars are subjected to.

The strict safety regulations enforced on cars were cited as a potential snagging point for the industry. James Trollope, PhD student at Coventry University, noted that the UK’s automotive industry is experiencing tougher crashworthiness regulations but has also carbon targets to meet. By 2020 vehicles must produce no more than 95kg of CO2 per km. In order to meet crashworthy standards, all vehicles need fairly lengthy crumple zones, but as Trollope’s supervisor, Professor Keith Burnham pointed out, in an age of high-techology materials these might not always be necessary. Materials that stiffen on impact, or use communication technology to predict and prevent crashes, could reduce the need for bulky design.