Lightening the load: new materials for automotive

The Engineer
July 2, 2012

In the automotive sector, mineral fillers such as glass fibre are being replaced by materials such as hemp

Steel could one day be replaced as the material of choice for high-volume auto manufacture, but installed plant and entrenched manufacturing processes make the transition difficult

We’re in a brave new world of engineering innovation, with new inventions and developments enriching our lives every day. Yet some aspects of the devices we depend on have changed little from their inception. It might seem like a contradiction, but sometimes even the most innovative sectors find there are barriers to innovation.

Take, for example, the most visible example of the way technology changed our lives in the last century: the motor car. In many ways, the cars on the roads today are unrecognisable from the contraptions and the early fruits of mass production that trundled down the roads of the 1910s and 1920s. But in others, they have changed very little.

‘People have the perception that cars are basically steel boxes with glass windows, and there’s a good reason for that perception,’ said Prof Richard Dashwood, head of materials and sustainability at the Warwick Manufacturing Group (WMG) and chief technology officer of the new High Value Manufacturing Catapult centre. ‘It is because, largely, they are. Something like 99.9 per cent of all cars on the road are steel-intensive vehicles.’

But the issue of ‘lightweighting’ — reducing the mass of the vehicle — is very much on the minds of automotive manufacturers at the moment. ‘It’s driven by European legislation on CO2 emissions,’ Dashwood said. ‘While you can improve your powertrain and aerodynamics, it’s lightweighting that will give you the biggest CO2 improvement.’

So why, considering the many advances in materials that have taken place over the last century and which have been adopted so enthusiastically by, for example, the aerospace sector, is the automotive industry still so wedded to its original materials?

There are exceptions to this rule. Among the most notable is Jaguar Land Rover, which switched to all-aluminium bodies in 2009, after Jaguar led the way with aluminium construction with the XJ and XK models. Aluminium is, of course, lighter than steel with comparable strength. ‘We didn’t decide to use aluminium because it was new or different,’ said Jaguar’s chief technical specialist for body engineering, Mark White. ‘It is because aluminium delivers significant benefits for drivers.’

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