Untreated banana pseudostem biocomposites as sustainable alternatives to synthetic composites: Micromechanical failure and void morphology analysis

Upcycling post-harvest agricultural crop residues into high-performance structural materials is vital for advancing the circular bio-economy and reducing industrial reliance on synthetic, energy-intensive composites. Banana pseudostem (Musa acuminata) represents an abundant, renewable lignocellulosic waste stream, yet its structural adoption is hampered by processing defects and mechanical performance scatter. This study presents an image-based micromechanical evaluation to prove the structural viability of chemical-free, untreated banana fiber biocomposites (Vf = 30%) as low-carbon alternatives to synthetic composites. Utilizing pre-acquired 2D X-ray radiographic defect maps, parameterised 3D Representative Volume Element (RVE) models were developed in Abaqus/Digimat to decouple fiber architecture from matrix void networks. High-resolution digital image processing revealed distinct void topologies: continuous inter-fiber channel voids in parallel-aligned (0?) layups versus localized crossover node pores in random mat architectures. Progressive damage modeling incorporating parabolic matrix yield and cohesive zone debonding demonstrated that parallel fiber alignment achieves a tensile strength of 39.63 MPa and a modulus of 3.00 GPa—representing a 53.0% strength enhancement over neat resin—by suppressing multiaxial stress concentration fields. These findings establish that raw, untreated agricultural residues can match structural benchmark requirements without chemical effluent generation, delivering an eco-friendly path toward sustainable industrial materials.