Influence of Fineness, Stiffness and Load-Displacement Characteristics of Natural Fibres on the Properties of Natural Fibre-Reinforced Polymers

The object of this study is the examination of micro-mechanical calculation models for the determination of stiffness and impact resistance of a fibre-reinforced epoxy-single-layer-composite. Cotton, ramie and man-made lyocell fibres were used in this work. In the calculation of the elasticity module it turned out that for ramie fibres there is a good consistency between theory and experiment. To correct the deviations caused by varying fibre characteristics correction factors were determined for cotton and lyocell fibres. Fibre characteristics are also of particular importance for the calculation of impact resistance. The adjustment required-particularly for cotton and lyocell fibres-was done by changing the relationship between debond length and critical fibre length. It was shown that it is basically possible to calculate the behaviour of natural fibre composites on the basis of precisely determined fibre properties.