Experimental investigation on natural fibre-reinforced composites with 3D orthogonal architecture: Perforation resistance and impact fatigue enhancement

This study investigates the dynamic response of novel 3D natural fibre-reinforced hybrid composites. Two reinforcement techniques were employed: 2D intralaminar and 3D orthogonal-through-the-thickness (3D-OTT). Jute bidirectional fabric served as the primary fibre phase, while sisal and curauá fibres provided secondary reinforcement. The 3D-OTT architecture incorporated transverse fibres woven through-the-thickness of the fibre preforms, providing additional reinforcement. Pure jute composites (JFRP) were also tested for comparison. Low-velocity impact (LVI) tests, including perforation and repeated impact, assessed energy absorption, load-bearing capacity, and impact fatigue life. Results showed that 3D reinforcement effectively suppressed crack propagation during impact. 2D sisal fibre based architecture specimens demonstrated the highest absorbed energy and peak load during perforation due to fibre delamination, which created large energy-absorbing debonding areas. While CURAUÁ composites exhibited similar energy absorption and peak loads for both architectures due to strong fibre–matrix interlocking, SISAL composites showed lower energy absorption in the 3D configuration. Compared to a jute-based reference (JFRP), both CURAUÁ and SISAL composites demonstrated superior perforation resistance (30% and 50% increases, respectively). The 3D architecture significantly improved impact fatigue life, increasing it by 3.6× for sisal fibre and 2× for curauá based specimens. Micro-CT analysis revealed distinct crack- arrest mechanisms: 3D reinforcement reduced crack propagation in sisal fibre reinforced specimens, while curauá specimens benefitted from its strong fibre/matrix interface for natural crack arrest.