Title : Experimental investigation of impact behavior of composite eco-structure
Abstract:
The sandwich structures are indeed lightweight composite structures that have been widely used in numerous sectors: automotive, aerospace, and naval and energy due to its high specific properties. However, these structures are vulnerable to impacts which may result significant damage such as cell wall buckling, core crushing, and the loss of structural integrity. Hence, nowadays, the implementation of new light-weight sandwich structures which leads to low carbon emission is the primary goal of all industry manufacturers. One way to achieve consists in the usage of resilient natural composite materials. An innovative sandwich proposed that uses natural material as a core and a bio-sourced composite as a skin, will be suitably denoted as composite eco-structure. Mechanical performance of natural wood is often unsatisfactory due to its weaker strength across the grain which could be overcome with a plywood core by utilizing its longitudinal superior strength in the direction across the grain. In order to manufacture a complete composite eco-structure rather than producing compromise solution, our project will develop new plywood core and natural Flax fibre reinforced epoxy composite skin which appear to be a promising and affordable way to manufacture resilient and high-performance composite eco-structures. This new resilient wooden core possesses a plywood core made of wooden plies (Poplar and Okume) with the four-fold increase in residual strength and have excellent properties in energy absorption, impact toughness and improved in-plane isotropy when manufactured as sandwich structures. This new natural composite eco- structure possesses a Flax FRP/epoxy composite skin that are made of stacking Flax fibre reinforced epoxy prepregs. Strengthening the outer skin of the above plywood core by above composite skin, the obtained structural member exhibits excellent specific properties with reference to all environmental aspects, safety considerations, impact resistance and energy absorption capabilities caused by its smooth stiffness transition characteristics of plies. Thus, such composite eco-structure was manufactured and tested to quantify the dynamic impact response, damage tolerance and the energy absorption capability. An advanced numerical model was developed to correlate the influence of the different plies in their impact response. Finally, such resilient composite eco-structures will be identified as a good competitive solution against current material (Kevlar honeycomb sandwich) used in the cargo bay floor applications.
