LOCALIZED HYBRIDIZATION USING BORON FIBERS: A ROUTE TO IMPROVE OPEN HOLE COMPRESSIVE PERFORMANCE

In this study we propose a novel localized hybridization concept to enhance longitudinal compressive performance of composites containing open holes. The concept involves hybridization in the form of selective placement of individual boron fibres locally near the vicinity of a hole within 0° plies of a quasi-isotropic laminate made from a carbon-epoxy prepreg. The manufacturing of these novel hybrid laminates is realized using an in-house developed fibre placement fixture to precisely place the boron fibres at the required locations. The mechanical performance of the manufactured concept is benchmarked against a non-hybrid baseline laminate under quasi-static compressive loading following the ASTMD6484 standard. The proposed hybridisation strategy results in a significant (≈35%) increase in compressive strength over the corresponding baseline laminate. The improvement in compressive performance can be attributed to changes in failure mechanisms due to the presence of the boron fibres within the hybrid laminates, as revealed by post-test failure analysis (using X-ray scans and scanning electron microscopy) and finite element simulations. Our research demonstrates the success of this first of its kind locally hybrid design aimed at improving open hole compressive performance.