Heavy metal driven off road

Engineers at Warwick University have taken a big step towards helping car manufacturers cut car weight drastically through greater structural use of lightweight composite materials.

Working in collaboration with car maker Rover, researchers at the university's Warwick Manufacturing Group have used composite material to construct a chassis beam to support the engine and steering rack. The structure reduces the vehicle subframe weight by 40 per cent, opening up the prospect of more fuel-efficient cars.

Gordon Smith, project leader, says that the beam is designed as a two-part moulding and manufactured from a glass-epoxy resin. It is intended that the new subframe will replace the traditional -piece metal assembly which has to be pressed and welded.

He says that the new frame has been designed for manufacturers making 50,000 to 200,000 vehicles a year.

"This process reduces subframe manufacturing time to three minutes resulting in predicted manufacturing cost savings of around 30 per cent in full production volumes," he said. This more than compensates for the higher cost of composite assembly compared to the conventional metal structure.

At an exhibition of current projects at WMG, a prototype of the new composite assembly was shown installed on the front end of a Rover car.

Dr Smith expects the results of the composite material development and new manufacturing techniques to be applied between 2000 and 2010.

"It is absolutely certain that far greater use will be made of composites as a primary structural material by the car industry. It is only a question of time."

As well as advances in materials and production technology, the researchers are employing sophisticated non-destructive methods such as thermal cameras to show stress patterns to evaluate performance of the composite structure under varying loads.

Rover and WMG are testing the new structure to evaluate its performance and Dr Smith says that initial results are "extremely promising. In fact they show the composite structure outperforming its metal rival as we predicted it would."