Micromechanical Analysis of Hybrid Composites

Abstract

Hybrid composites, composed of two or more fibre types within a common matrix, offer mechanical characteristics that may not be attainable with single-fibre composites. This study investigated the micromechanical behaviour of hybrid composites using the unit cell approach, studying the synthetic–synthetic, natural–natural, and natural–synthetic hybridisation cases, hence, the influence of combining the different fibres, and the effect of varying volume fractions of fibres of the hybrid composites.

Single fibre composites, carbon, glass, hemp, and ramie were analysed first to investigate the performance of the single fibres; the analyses showed that glass fibre-reinforced polymer had the highest transverse and shear moduli, whereas hemp fibre had the highest Poisson's ratio. Carbon and glass fibres showed better stress distribution for synthetic-synthetic fibre cases, whereas hemp-ramie's natural–natural pairing was less optimal. Among the natural–synthetic combinations, hybrid composites with hemp, particularly when combined with glass, showed increased stress distribution over those incorporating ramie.

Despite the slightly lower performance compared to carbon, hemp showed to be a cost-effective alternative to carbon fibre, especially when combined with glass. On the other hand, introducing ramie into the hybrid composites led to a decrease in the effective transverse, shear moduli and Poisson's ratio of the hybrid composites when combined with other fibres. Therefore, hemp was shown to be a more optimal natural fibre to replace carbon fibres, whereas ramie may be optimal for less mechanically demanding applications.