Low-velocity impact responses of Napier fibre/polyester composites

The low-velocity impact response of Napier grass fibre/polyester composites was investigated. Napier grass fibre was used as the reinforcing material in polyester composite laminates. Napier/polyester composites specimens of 10%, 15%, 20%, 25% and 30% fibre volume fraction were produced using a compression moulding machine. The specimens of the mentioned fractions were impacted with a 5 J energy level using an instrumented drop weight impact tester (IMATEK IM10). The fracture damage of the impacted specimen was analysed using a field-emission scanning electron microscope (FESEM). The experimental result shows the relationship between the volume fraction percentage of Napier fibres and the impact force, energy absorbed and stiffness of the composites. Pure polyester specimens displayed brittle behaviour with a lower peak force, lower energy absorption and less time to failure compared to Napier reinforced composites. The impacted Napier/polyester composites with fibre loading of 30% show higher absorbed energy, peak force and longer time to failure. Furthermore, the experiments on each fibre volume fraction revealed increasing load-bearing capability and energy absorption with an increase in the volume fraction of Napier fibre. The FESEM observation exhibits various failure mechanisms such as fibre breakage, fibre pull-out, matrix cracking and fibre splitting.