An Advanced Technological Lightweighted Solution for a Body in White

Abstract

Funded by the EC FP7 Program, EVolution project is using the Pininfarina Nido concept car as a baseline for its activities, with the goal to demonstrate the sustainable production of a full electric 600 kg vehicle (FEV). The project has to be finalized by the end of 2016. The existing Body in White (BiW) has been completely reviewed through a design strategy aiming to reduce the number of parts and using innovative lightweight materials and technologies. The considered Al technologies applied on high performances Al alloys provide the opportunities to obtain components with complex geometries and low thickness, merging different parts into one unique element. Besides, it is possible to process a variable thickness element with a single operation.

A “green sand mold” technique allows co-casted joints among elements produced with different Al manufacturing processes.

The potential cost reduction and process simplification in terms of time and assembly are promising: current state-of-the-art, based on traditional moulds, does not allow these opportunities.

The BiW has been hybridized in certain areas of the underbody with a composite material of the PA family, reinforced with GF. This material has been obtained improving existing ones and developing a production process suitable for scaling to commercial requirements, throughout an advanced sheet thermoforming and 3D-injection method (CaproCAST process).

Novel polypropylene nanocomposites (PNC) based on silicate and glass fiber layers demonstrate improved toughness and stiffness and have been selected for crash cross beam and side door. Polyurethane foams based on recycled polymers are explored as sustainable energy-absorbing filling in cross beam sections.

Structural epoxy adhesives have been considered to join the BiW parts and welding points are reduced in number: in certain areas spot-welds have been used only to tack the parts during polymerization.

In addition to the previous results, current weight of the BiW is 115 kg versus 160 kg of the baseline car. An FE-analysis on the virtual full vehicle indicates a good structural behavior, considering EU standards of crash homologation and global static and dynamic performances.

The developed architecture and the integration of lightweight materials will ensure that the EU maintains its competitiveness against the Asian and United States automobile industries.

This topic is focused on the results obtained on the BiW in terms of design strategies, Al and composite materials innovative technologies and joining methods.