Low-velocity impact and static behaviors of high-resilience thermal-bonding inter/intra-ply hybrid composites

This study prepared inter/intra-ply hybrid composites reinforced with sandwich-structure recycled Kevlar nonwoven/glass woven compound fabric. Negative-depth needle punching and thermal bonding were applied to strengthen the structure with two compound cover plies and a fluffy cushioning center ply. The effects of center ply areal density, needle punching depth, and fiber blending ratio on the static and dynamic impact resistance behaviors of the composites were investigated. The results indicated that areal density significantly influenced the static and dynamic impact behaviors, which were both enhanced by the promotion of thermal-bonding points. As the needle punching deepened, the static and dynamic puncture resistances represented opposite tendencies because of different failure mechanisms. Static friction was the dominant factor for static puncture resistance, whereas kinetic friction was the dominant factor for dynamic puncture resistance. A similar phenomenon was observed when fiber blending ratio was varied. In terms of the non-penetrating dynamic cushioning test, areal density was the most distinct influence factor on cushioning behavior and the hybrid composites sample with an areal density of 700 g/m2 could eliminate up to 66.5% of the incident force. Therefore, the inter/intra-ply hybrid composites showed high impact resistance and excellent dynamic cushioning property.