Development of a Manufacturing Strategy for Moderate Volume Production of a Composite Vehicle Structure 982400

In order to achieve commercial success, alternative vehicle structures must offer a favorable balance of performance and economics. Whether for traditional or alternative powerplants, composite structures have the potential for significant weight savings, but to date have been limited to very low production volumes. Consumer demand requires that electric vehicles must have comparable range and acceleration relative to internal combustion engine vehicles. A major obstacle to this goal is the mass of batteries needed for this level of performance. As a result, electrical vehicle design strategies have aimed at significantly reducing the weight of vehicle structures. Examples include the aluminum intensive EV-1 from General motors and the composite bodied Sunrise from Solectria.

This paper examines the development of a manufacturing strategy for a lightweight, all composite body-in-white. The process involved the assessment of ten different vehicle design strategies incorporating a range of fabrication processes including SCRIMP, RTM, hand lay-up, pultrusion, filament winding, SMC, and thermoplastic/glass compression molding. Technical Cost Models were employed to make comparisons of relative manufacturing economics, the results of which were fed into a multi-attribute decision matrix to down-select the most viable processes for the target vehicle performance and cost. A combination of cost modeling and factory process simulation was applied to refine manufacturing design and process flow.

The methodology used in examining the alternative fabrication processes is discussed along with resulting advantages and disadvantages of specific technologies with respect to the program objective of low cost at moderate volume production.