An Experimental Study of the Behaviour of Sandwich Composite Panels under Low-Speed Loading

While natural fibres may not match the mechanical properties of synthetics ones, they offer the environmental benefits. Hybridisation is one approach to enhance the mechanical performance for relatively moderate strength applications. In this investigation, the characteristics of sandwich composites with carbon fibre reinforced laminates as the skin structure with core materials of hemp fibre, Nomex honeycomb, and 3D Core infusion foam under quasi-static loading have been investigated and compared with the response of plate using flax fibre reinforcement for the skin laminate and the core materials remains the same. The samples were manufactured by hand layup and autoclave curing for the skin laminate and then glued to the core material. They were conducted using the universal testing machine at the loading rate of 10 mm/min. Two different fibre orientations, [0°/30°/60°/°]s and [0°/±45°/°]s were evaluated. The data collected from the tests were utilised to obtain the maximum load bearing capacity and energy absorbed by the samples. Additionally, the failure modes for all the samples were observed. Results indicate that panels with hemp fibre core exhibit superior mechanical properties compared to the other core materials, though with a rise in the weight. Samples with honeycomb and foam core demonstrated similar mechanical performance. Furthermore, the study reveals that different core materials are compatible with specific stacking sequences based on the material of the fibre reinforcement and that the spiral arrangement of [0°/30°/60°/°]s is a recommendation to consider for improving damage resistance.