Publication
Composite materials are increasingly used in high volume automotive applications, usually as a replacement for assemblies of multiple metallic parts such as stamped and spot-welded steel sheets. One of the motivations is to reduce tooling and assembly costs, in particular at lower production volumes. Other key driving forces are increased styling freedom, reduced system cost and weight reduction. With soaring fuel prices and environmental focus on CO2 emissions, reducing vehicle mass is presently a major concern for the automotive industry. Nearly all the composites used for high production volume automotive applications today are based on short or medium length random glass fibre technologies. However, there is a great interest in extending the range of materials and processes to advanced composites (continuous aligned fibre and high fibre volume fraction materials) as they would enable superior mass specific properties compared with metals, resulting in substantial weight savings. Advanced structural composites have, however, not seen widespread use in high volume automotive applications due to a series of inhibiting factors. These typically comprise higher cost and risk when compared with standard metal forming solutions. Novel composite technologies target some of the current drawbacks, but need to mature before being widely accepted in the high volume market. It is therefore necessary to not only evaluate and develop these technologies further, but also to propose practical tools to evaluate their performance and risk level, until they reach a state where their mechanical and economic performance clearly outweighs the risks associated with their implementation. The present work aims at developing a methodology to facilitate the evaluation of new composites manufacturing technologies, while at the same time decreasing the risks associated with implementation. A second objective is to identify suitable composite material and process technologies, which will offer competitive economic and performance gains. An evaluation methodology is thus proposed and validated with a practical case study based on the analysis of two novel structural composite processes for high volume automotive components. A spare wheel well was chosen as the demonstrator since it is a structural component and is assembled as a bolt-on part, making integration within the vehicle easier. Weight assumptions, which are used as performance criteria for all examined materials, have been obtained through extensive design and FEA studies for both strength and stiffness based criteria. Cost, discounted part price, investment and other figures of merit are used as economic performance criteria and have been established through novel technical cost evaluation techniques. The presented methodology manages uncertainties and evaluates performance, and is used as a basis for establishing relations between opportunities and risks. To achieve this, tools are introduced which support the ev