A study on the low velocity impact response of hybrid Kenaf-Kevlar composite laminates through drop test rig technique

Abstract

This paper presents the effects of a low velocity impact test on the hybrid composites of kenaf and Kevlar. In recent years, there has been a trend to replace the synthetic fibers, used as reinforcement in epoxy composites formation, with natural fibers due to their low cost, high flexibility, biodegradability, and recyclability. In order to surpass the low mechanical strength of natural fibres in comparison to the conventional composites, hybrid composites combining both types of fibres was introduced. This combination will lead to improvement in the mechanical strength and biodegradability of epoxy composites, which is important for waste reduction and protection of the environment. The materials were fabricated in a seven-layer laminate configuration utilizing a ratio of 3:1:3 (Kevlar:kenaf:Kevlar) for a hybrid composite. This combination earlier had been found to give the best tensile test performance. An original composite with seven layers of kenaf (full kenaf) and one with seven layers of Kevlar (full Kevlar) were also prepared for comparison. The selected specimens underwent a low velocity impact test with variations in energy. The failure mode was observed. The results showed that a seven layer laminate only withstood an impact energy below 30 Joules, and it failed when the impact energy approached 40 Joules. The hybrid composites approached the quality performance of full Kevlar and exhibited better mechanical properties than full kenaf composites. Therefore, the novel hybrid composites can be used for product development in environmentally friendly technologies.