Toward Sustainable Lightweight Composite: Effect of Resin and Pineapple Leaf Fiber Orientation on Mechanical Performance

The development of unmanned aircraft presents the challenge of designing structural components that are both lightweight and environmentally friendly, while maintaining high mechanical performance to withstand aerodynamic loads and protect internal systems. This study investigates the effect of resin type and fiber orientation on the fracture toughness and specific strength of composite materials reinforced with pineapple leaf fiber—an agricultural waste with renewable potential. An experimental approach was employed to quantitatively assess the influence of resin type and fiber orientation on the mechanical performance indicators. The result indicates that epoxy resin combined with 0° fiber orientation yields the highest fracture toughness at 31.66 MPa√ m , while polyester resin with the same fiber orientation achieves the highest specific strength at 59,642.2 N.m/kg. These findings demonstrate that optimizing fiber orientation and resin selection significantly enhances the mechanical properties of natural fiber composites. Pineapple leaf fiber, when processed appropriately and paired with suitable resin systems, offers a promising, sustainable alternative to synthetic fibers in lightweight structural applications.