Composites with ROHACELL® - A New Dimension of Weight Reduction

Roof element of the light-weight demo model of Lotus Exige

Apart from energy-conscious driving and power train improvements, weight reduction in vehicles is the preferred method for saving fuel and reducing CO₂ output. While the weight-reduction potential of conventional metal structures is approximately 10%, sandwiched composite structures made of ROHACELL^® and CFRP can save 50% and more of weight in the outer skin. This has been documented in studies involving a Golf V or the Lotus Exige. Based on the light-weight demo model of the Lotus Exige, engineers were able to prove that the use of cover layers of approx. 0.7 mm CFRP and 2 mm ROHACELL^® 711G-F not only resulted in weight savings of 30% in the cladding, but also in a significant improvement of the inherent stiffness compared to a conventional CFRP structure.

This is of particular interest for future urban vehicles or electrical cars, in which reduced weight will significantly contribute to downsizing the power train and improving range.
Super sports vehicles and Formula 1 cars already use Boliden sandwich structures with ROHACELL^® for further gains in acceleration and handling because of lower weight.

ROHACELL^® can easily be shaped into 3D cores with thermoforming processes. Thanks to its high temperature resistance, the material allows for short cycle times over 100 °C with advanced resin and inline coatings.

ROHACELL^® is free of FCKW, meets the heavy metal requirements of the End of Life Vehicles Directive 2000/53/EC and is listed in the IMDS.
Studies of KTH in Stockholm, Cranfield University, and Lotus Engineering have documented the positive crash properties of ROHACELL^®. Simulation values for the crash behavior of ROHACELL^® IG are available upon request.