Extrusion-based additive manufacturing of banana fiber reinforced PLA biocomposites with bioinspired infill patterns

Nature is a reliable laboratory, offering a rich variety of successful solutions to a broad array of scientific and engineering problems. The inspiration from nature has prompted the development of novel designs for high-performance materials and technologies using additive manufacturing. However, the combined influence of bioinspired infill architectures and natural fiber reinforcement under multi-objective optimization remains insufficiently explored. In this study, banana fiber-reinforced PLA composites were fabricated using fused deposition modeling using bioinspired infill patterns such as gyroid and honeycomb. The Taguchi L9 approach was adopted to evaluate the impact of infill density, raster angle, and fiber reinforcement ratio on the mechanical properties of the 3D printed samples. The results reveal that process parameters and infill architecture significantly influence the structural and mechanical behavior of the composites due to variations in load transfer and stress distribution mechanisms. The fourth print condition showed the highest values of tensile strength (62.45 MPa), tensile modulus (5.04 GPa), and natural frequency (60.36 Hz). Maximum values of flexural strength (79.78 MPa) and compressive strength (60.73 MPa) were recorded for the seventh print condition, while maximum impact strength (22.17 kJ/m 2 ) and elongation percentage (1.82%) were recorded with the first condition. To resolve conflicting property trends, VIKOR-based multi-criteria decision analysis was applied, identifying the third condition (50% infill density, 45° raster orientation, 9% banana fiber loading, honeycomb pattern) as optimal parameter combination with balanced mechanical performance. The findings demonstrate the potential of integrating bioinspired design and sustainable composites for enhanced structural applications in additive manufacturing.