This paper investigates tensile, flexural, and dynamic mechanical properties of natural and hybrid thermoset composite laminates made from flax/glass and jute/glass fibres. Hybrid laminates with various stacking sequences were manufactured by vacuum infusion method. Weight and cost of composites decreased using cheaper and lightweight natural fibres (flax and jute). Results showed that composite laminates made from natural fibres had higher specific strength values when the results were normalised to same glass fibre volume fraction, although they had lower tensile and flexural strength than that of glass composites without normalization. Composite elastic properties were predicted using classical lamination theory through rule of mixture and Halpin–Tsai models, and compared with experimental values. Changing the stacking sequence did not affect the tensile strength and modulus of composites significantly, whereas there were notable differences on flexural strength of composites when the outer layers contained glass fibres. Dynamic mechanical analyses showed similar results as flexural test, while natural fibre and some of hybrid composites had higher damping characteristics than glass-reinforced composites.

No abstract

No abstract

Advanced composite materials are widely used in civil and military applications due to their superior specific strength and stiffness. However, they are susceptible to damage during impact loading. In order to improve the impact performance, yarn hybridisation and fibre architecture have been investigated in this study in order to evaluate their influence on the damage tolerance (i.e. post- impact flexural strength) of glass composite laminates. Two types of yarn have been used here, namely, pure glass yarns as a bench-mark and hybrid yarns (glass-polypropylene) to manufacture non-crimp and woven (twill and satin) fabric composites. The composite laminates were then subjected to low-velocity impact tests at various impact energies. Afterwards, post- impact flexural strength has been evaluated with a four-point bending test. It has been observed that the non-crimp and woven hybrid composites laminates displayed smaller damage areas compared to the non-crimp glass composites laminates. In addition, although the hybrid laminates have exhibited lower flexural strength properties than the non-crimp glass laminates, the former has shown higher post-impact flexural strength. Fractography analysis has suggested here that the damage failure modes such as intra-yarn cracks have been produced in the hybrid yarns laminates and intra-yarn and inter-yarn cracks have been produced in hybrid fabric laminates. These damage failures have contributed for absorbing impact energy leading to an enhancement of the damage tolerance of the hybrid laminates.