Ultra-stiff and strong composites for structures with complex geometries

Research Project, 2018 – 2019

The material to be developed finds its inspiration in nature. Nature’s structural materials feature high stiffness, strength and damage tolerance. These materials features staggered stiff inclusions embedded in a soft matrix, where the stiff inclusion carries the load and provides stiffness. Whereas the thin soft matrix transfers loads via shear and provides slip-planes in the material. Furthermore, the inclusions are considered two-dimensional materials as they have large length to thickness aspect ratios. In the proposed pre-study we mimic the discontinuous architecture of natural composites to realise significantly stiffer and stronger man-made composites than ever before. Here, ultra-high modulus CFRP thin tapes constitute the stiff two-dimensional inclusions. Given the tape thickness of approximately 20 micrometre, very high volume fractions of the stiff tapes can be achieved. The use of short, thin, tapes is expected to allow processing of structures with complex geometries with ultra-high modulus carbon fibres. Process ability is expected as the individual stiff tapes will be able to slide relative each other during manufacture. We aim to develop a manufacturing process to make isotropic composite laminate with an in-plane stiffness of at least 150 GPa, and an in-plane tensile strength in excess of 700 MPa. With access to such materials at reasonable cost, significantly lighter structures across transport modes can be made in the future.