Eco-Efficiency Performance for Multi-Objective Optimal Design of Carbon/Glass/Flax Fibre-Reinforced Hybrid Composites

An eco-efficiency optimisation study on unidirectional carbon/glass fibre-reinforced hybrid composites with natural fibre (i.e., flax) and without flax is presented in this paper. The mechanical performance was assessed by determining the flexural properties obtained via finite element analysis (FEA)-based simulation. Given the required flexural strength, optimal candidate designs were found using a set of design rules and regression analysis, with minimising the cost and weight being the objectives. An eco-efficiency framework was applied to determine the eco-efficient hybrid composites. Life cycle assessment was an indispensable component of the framework as it helped determine the life cycle environmental impacts and costs of the hybrid composite materials. The environmental impacts and cost values were converted to the eco-efficiency portfolios of these composites for both comparison and selection purposes. The hybrid composites using bio-based flax fibre have been found to be eco-efficient in most of the cases due to the avoidance of energy-intensive and expensive reinforcing materials. The environmental impacts of the hybrid composites using flaxes are 12 to 13% less than the ones using no flaxes and the former are 7 to 13% cheaper than the latter, making the flax-based hybrid composites eco-efficient.