A study on the mechanical properties of flax preforms reinforced epoxy composites

Abstract

The present investigation covers the studies conducted on the effect of varying the number of preform layers and changing the lay-up architecture on the mechanical properties of plain woven flax and rib knitted flax reinforced composites. In addition, the effect of the above variables on the mechanical properties of sequentially stacked flax knitted/woven reinforced composites was also studied. The mechanical properties taken into consideration during the course of the study were the tensile, flexural, impact and compressive properties. Natural fibre composites are being extensively explored by research institutes, automobiles, aviation, marine, civil and packaging industries as an environmentally friendly alternative to synthetic fibre composites. Further, textile preforms manufactured by conventional textile technology such as weaving and knitting are known to offer attractive intra and inter-laminar strength, damage tolerance, lower cost and versatile design potential. Hence in the present study, the mechanical properties of flax - woven, knitted and sequentially stacked knitted/woven preform reinforced composites were studied. The tensile and flexural properties of the textile reinforced composites depend on the number of fibre bundles bridging the fracture plane. It was observed from the studies on the tensile and flexural properties of the composite, that weft wise mechanical properties improved with the change in lay-up architecture in the case of 16-layered woven composite. The impact properties of composite material are directly related to its overall toughness. The crushing behaviour of the composite is dependent on the fibre architecture and on the fibre content. The buckling load of the laminates in woven, knitted and sequentially stacked knitted/woven composites improves with increase in number of preform layers and thickness. The failure modes and corresponding morphology of the broken samples are systematically characterised by scanning electron microscopy in this study. newline newline newline