Showing papers by "Paul Robinson published in 2023"
TL;DR: In this article , zone-based hybrid laminate concepts for improving the high-velocity impact (HVI) response of baseline carbon fibre-reinforced polymer (CFRP) composites while maintaining similar areal weights and retaining substantial inplane mechanical properties by requiring that about 80% of the baseline CFRP is kept in the hybrid concepts.
Abstract: We propose novel zone-based hybrid laminate concepts for improving the high-velocity impact (HVI) response of baseline carbon fibre-reinforced polymer (CFRP) composites while maintaining similar areal weights and retaining substantial in-plane mechanical properties by requiring that about 80% (by mass) of the baseline CFRP is kept in the hybrid concepts. We identify three zones along the thickness of the laminate according to their role during HVI and implemented tailored materials in these zones to improve the HVI response. We studied a wide range of materials, including: fibre reinforcements of carbon (thin- and thick-plies), glass, aramid and ultra-high molecular weight polyethylene (UHMWPE); a shape memory alloy/carbon weave; and ceramic, alumina and titanium sheets. All laminate concepts have similar areal weights for a meaningful comparison. After defining the various concepts, we manufactured and measured their specific dissipated energy under HVI, and finally carried out post-mortem analysis (including C-Scan and microscopy). The results show up to 95% improvement in energy dissipation over the baseline quasi-isotropic (QI) CFRP configuration.
TL;DR: In this paper , an extremely simple methodology based on commonly used thermoplastic interleaves has been demonstrated to achieve repeatable easy-repairing and self-sensing functionalities, alongside enhanced mechanical performance in comparison with unmodified carbon fibre/epoxy system.
Abstract: Structural composites with smart functionalities of self-healing and self-sensing are of particular interest in the fields of aerospace, automotive, and renewable energy. However, most of the current self-healing methodologies either require a relatively complex design of the healing network, or sacrifice the initial mechanical or thermal performance of the carbon fibre composite system after introducing the healing agents. Herein, an extremely simple methodology based on commonly used thermoplastic interleaves has been demonstrated to achieve repeatable easy-repairing and self-sensing functionalities, alongside enhanced mechanical performance in comparison with unmodified carbon fibre/epoxy system. Moreover, due to the high glass transition temperature of the thermoplastic, the repairable composites are shown to have an unchanged storage modulus up to 80 °C, solving the previous limitation of repairable epoxy matrix systems with thermoplastics. High retention of peak load (99%) and a decent recovery of interlaminar fracture toughness (34%) was achieved. Most importantly, the mechanical properties remained greater than the unmodified system after four consecutive cycles of damage and healing. Repeatable in-situ damage sensing was achieved based on the piezoresistive method. This “new” discovery based on an “old” approach, which is fully compatible with current composite manufacturing, may overcome existing conflicts between mechanical performance and healing functions, providing a new solution to extend components’ service life towards a more sustainable development of the composite sector.