Effect of stacking sequence on tensile, flexural and thermomechanical properties of hybrid flax/glass and jute/glass thermoset composites

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.