Design Rules Challenge to Deliver a Step Change in Composites Manufacture

Recent works at Bristol has demonstrated that what appear to be relatively minor details of the composites design process can have very significant impact on the success and costs of manufacture. Even the selection of the grade of prepreg used can make a difference up to a factor of two on the labour content in manual lay-up; and elements of the part design, such as ramp angles in cored panels, have a major impact on the time and quality of manufacture in both manual and automated lay-up. The roots of the composites industry are in the aerospace sector and much of the design work that is carried out has internalised a set of explicit and implicit rules that have largely gone unchallenged in any formal sense. These rules were developed in the formative years of the composites industry and in part reflect the uncertainty about designing with a novel class of materials, especially where early material grades were extremely brittle. Over time these rules have impacted on materials development but also settled into a very prescribed design flow.

This study will take the first steps towards a wider investigation of the impact of design decisions – encompassing implicit and explicit design rules, materials selection, geometrical features, and the forming and moulding processes; on both costs and performance.  The aim is to demystify and clarify composites design processes such that safe, reliable, cost-effective designs can be generated that are neither over nor under specified for the proposed application, and demonstrate these benefits. A step change in composites manufacturing costs or performance cannot be achieved without a fundamental reappraisal of the design processes, and this work will help to put in place the foundations to support that aim.