Experimental and numerical investigation on failure behavior of pin joint prepared from rice straw/Epoxy/g-C₃N₄ nanocomposite

Abstract Rice straw is a major agricultural waste biomass, which is to be burnt and causes air pollution. This study focuses on the development and analysis of sustainable rice straw composites using graphitic carbon nitride (g-C 3 N 4 ) nano filler. The nano filler, g-C 3 N 4 were prepared in-house using the pyrolysis method. This study investigates the enhancement of mechanical performance in rice straw reinforced epoxy composites through the incorporation of 0.75 wt% g-C 3 N 4 nanoparticles and fiber surface treatment. Experimental tensile and bearing tests were conducted on double pin joint laminate specimens to evaluate the influence of these modifications. The untreated composite exhibited a maximum experimental bearing stress of 37.60 MPa and a shear-out failure mode, whereas the treated and nanoparticle-reinforced composite demonstrated a significantly higher bearing stress of 59.10 MPa with progressive bearing failure at both holes in the joint. Finite Element Analysis (FEA) using the ACP module was used to simulate stress distribution and predict failure behavior, showing close agreement with experimental results. The Tsai-Wu failure criterion was used to predict safe load capacities, yielding 889 N for neat untreated rice straw epoxy composites and 1689 N for treated and filled rice straw epoxy composites, indicating a 90% improvement in load-bearing capacity. The study confirms that the synergistic effect of nanoparticle addition and surface treatment effectively enhances fiber–matrix bonding, improves failure resistance, and significantly increases the structural performance of rice straw epoxy composites.