Using unwrapped filament tows to strengthen sandwich composites: Puncture and bursting resistance

The combination of appropriate materials and structural design can compensate for flaw of a single pattern, providing the products with better functionalities. In this study, the custom-made nonwoven fabric machine can unwrap the filament tows before needle punching stage. Sandwich composites are proposed, consisting of two nonwoven fabrics as surface layers and laminated loops of filaments as the core. The puncture resistance of the sandwich composites are examined in terms of weight of filament loops and needle-punching depth, examining their influences. The employment of filaments has a remarkable influence on the mechanical performance of the composites. GF4G has static puncture resistance, dynamic puncture resistance, and bursting strength that are 89%, 30%, 88% higher than those of GF1G; 332%, 127%, and 500% higher than those of 2G; and 671%, 400%, and 1260% higher than those of G. Using filaments to reinforce nonwoven fabrics only requires simple equipment and easy operation. Furthermore, based on the requirements of different final products, diverse filaments and multiple parameters can be combined, thereby providing the composites with efficient production, solid reinforcement, and broad applications.