3D printed wood-fiber reinforced architected cellular composite beams with engineered flexural properties

This study explores the integration of cellulose-based compounds into a biobased polymer to create highperformance sustainable materials with improved properties. The elastic flexural characteristics of 3D printed composites, comprised of polylactic-acid (PLA) biopolymer reinforced by a variety of waste wood fiber weight percentage (2.5%-15%), are investigated. Initial steps involve producing wood-fiber reinforced PLA (WF-PLA) filaments and the 3D printing of test specimens. Experimental outcomes reveal enhanced flexural modulus (60% increase), rigidity (72% increase), strength (39% increase), and failure strain (21% increase) alongside reduced composite coupon density (5.2% decrease), attributed to wood fiber incorporation. To achieve lightweight and sustainable structural components with tunable attributes, architected composite cellular beams are introduced. These beams comprised of wood-fiber reinforced composites feature cross-sectional unit cells with one or two reflection symmetries, showcasing the synergy between architecture and material composition in enhancing quasi-isotropic flexural rigidity. Investigation on the flexural rigidity ratio ([EI]yy/[EI]xx) involves theoretical modeling, computational analysis, and experimental validation using 3D printed samples. WF-PLA filaments enable the 3D printing of engineered quasi-isotropic cellular beams, termed "Isoflex", that demonstrate up to 130% enhanced specific flexural rigidity (bending rigidity-to-mass ratio) and up to 70% improvement in flexural rigidity ratio to have isotropic flexural properties, compared to pure PLA beams. This study introduces WF-PLA engineered cellular composites as a sustainable avenue for tuning structural properties, contributing to the realm of additive manufacturing.