Volumetric changes in non-homogeneous materials

During curing of thermosetting composites the resin undergoes cross-linking reactions that lead to an increase of material density and reduction in volume. The process of volume reduction, usually referred to as chemical shrinkage, can lead to development of high locked-in stresses. Both thermal and resin shrinkage induced stresses can subsequently cause distortion and premature cracking of the polymeric mouldings as shown in Appendix A. A deeper understanding of cure shrinkage mechanisms is critical to LMAT in order to design manufacturing processes and tooling for compoistes with high dimensional tolerances. This project will provide the required understanding of material behaviour by combining physical testing and numerical simulation to find the best method of measuring cure shrinkage induced strains and stresses. A successful outcome to the project will help to maintain and enhance the UK's position at the forefront of composites manufacture.