Quasi-static perforation response of inter-ply hybrid polypropylene composites at various temperatures

This study is motivated by the lack of knowledge in the research of mechanical characterization of thermoplastic composites (TPCs) with additional fiber hybridization. To enhance the mechanical properties of long glass fiber-reinforced polypropylene (PP) composite, hybridization via alkaline-treated aramid and carbon fabrics is performed. High performance fabrics modified with 10 wt.% sodium hydroxide (NaOH) aqueous solution are incorporated into the PP composite as reinforcements. Herewith, four arrangements (hybrid composites) for two different reinforcements and two different stacking configurations and the monolithic composite are separately investigated in terms of quasi-static perforation behavior. Failure mechanisms are also evaluated at macro level by visual observations and micro scales through a scanning electron microscopy (SEM). The experimental results provide a basis for selecting fiber-enabled hybridization and lay-up configuration with improved perforation resistance. Moreover, the influence of test temperature is reported for three different values as 20°C, 60°C, and 100°C. Based upon the results, the maximum penetration force of hybrid configuration with single-layered aramid fabric reinforcements is approximately 15.5% higher than that of single-layered carbon fabric reinforcements at 60°C test temperature. It is further observed that the absorbed energy improves as the number of fabrics is increased in both aramid and carbon reinforcements. The test temperatures significantly affect the failure mechanisms of TPCs. A smaller damaged area at the penetrated faces of the hybrid structures is obtained by comparison with the monolithic TPCs.