NSF Composite Sheet Forming Workshop

The breakthrough of advanced composite materials in various applications has occurred to a smaller extent than might have been expected previously, mainly due to the high integral costs of composite products: a high cost of manufacturing added to the already expensive raw material. There is a clear need for improved cost-effectiveness. The key issues are considered to be: cheaper production processes, higher production rates and predictable component accuracy. Thermoplastic composites have a good potential, but the current knowledge of the material behaviour under full-scale production conditions is still inadequate. Academic research can produce the numerical tools to assist in building up the required know-how. Composite forming simulations will be a useful tool to predict e.g. process distortions and the occurrence of wrinkling, thus reducing cost of rework and lead time. Previous Work In the BriteEuram programme PRECIMOULD (BE97-4351), a prototype software package was developed to predict tooling geometry corrections and processing conditions to achieve accurate 3D shapes of composite products. To this end, the material behaviour and the processing factors affecting composite part accuracy had to be understood and quantified. Appropriate models were developed for autoclave and RTM processing of various Woven Fabric (WF) reinforced thermoset materials and verified by experiments. Full scale demonstrators were designed and produced based using the PRECIMOULD solver, implemented in the LUSAS finite element package. Current Work A national research project on high precision rubber press forming of thermoplasti