Using laminate hybridisation (CFRP-GFRP) and shaped CFRP plies to increase plate post-buckling strain to failure under shear loading

Previous works have established the response and failure behaviour of hybrid (CFRP-GFRP) laminates when subjected to a wide range of destabilising loads. However, to date no works have quantified the influence of selective laminate shapes and hybridisation on plate post-buckling strain to failure. Thus, this paper investigates the plate collapse behaviour of a novel X-braced hybrid (CFRP-GFRP) twill woven laminate, subjected to in-plane shear loading. An experimental and numerical investigation is undertaken, including the consideration of a baseline pure CFRP laminate design. The experimental results illustrate that despite having less CFRP material, a hybrid laminate design with shaped CFRP plies can exhibit a greater strain to failure and buckling to failure load ratio, with only a marginally lower initial plate buckling load. Additionally, the experimental and numerical analysis reveals that the failure mechanism of the hybrid laminate is dominated by shear damage and fibre compressive breakage, whereas compressive and tensile fibre breakage dominate the conventional baseline laminate behaviour. Due to the prevalence of the shear damage and hence cracking and plastic deformation of the matrix, the novel hybrid laminate demonstrates a more gradual failure than the standard baseline laminate design, with failure strains significantly higher than that of the baseline laminate design.