Fibre composites comprising Ultra High Molecular Weight Polyethylene (UHMWPE) fibres in a polyurethane or polyethylene matrix are increasingly finding application in industries ranging from lining of air cargo containers, blades in wind power installations to forming critical elements of vehicle and personal armours. The interest in such materials initially arose from the fact that commercial UHMWPE fibres attain tensile strengths of approximately 3 to 5 GPa at a density less than water. However, recent experimental investigations suggest that the exceptional performance of composites comprising UHMWPE fibres is not solely due to the high fibre strength but largely associated with the extreme anisotropy of the composites: the tensile strengths and moduli of such composites is in the GPa range while their shear moduli and strengths are typically in the low MPa range. The mechanics of such strongly anisotropic composites (and materials) has remained unclear and here we shall focus on trying to understand the mechanisms via which anisotropy enhances composite performance in certain applications.
The seminar will report a comprehensive experimental and numerical investigation of the mechanics of these composites under both static and dynamic loading conditions. The understanding of the range of deformation/failure mechanisms gained from this combined numerical/experimental investigation will be used to motivate a discussion on a new class of UHMWPE composites that have the potential to further enhance performance.