Effect of geometric irregularity and relative density on the tensile behavior of Voronoi-based PLA/chitosan bone scaffolds

In bone tissue engineering, tailoring scaffold architecture to meet location-specific mechanical requirements is essential for effective load transfer and tissue regeneration. In this study, polylactic acid (PLA)/chitosan Voronoi scaffolds with irregularity (IR) values of 0, 0.3, 0.5, 0.7, and 1 and relative density (RD) levels of 25% and 40% were fabricated using fused deposition modeling (FDM), based on the ISO 527 standard with minor modifications, and subsequently infiltrated with chitosan. Uniaxial tensile tests were performed in triplicate for each architectural configuration to ensure repeatability. Beyond conventional mechanical characterization, the primary contribution of this work lies in the integration of the minimum cross-sectional area methodology with Digital image correlation (DIC) and Finite element (FE) analysis, enabling a mechanistic interpretation of tensile failure and strain localization in relation to scaffold architecture. Experimental results were compared with FE simulations assuming PLA mechanical properties only, as chitosan primarily functioned as a bioactive infiltrating phase with negligible load-bearing contribution. Fracture behavior was further interpreted through the combined use of DIC strain fields, FE predictions, and minimum cross-sectional area identification to elucidate failure initiation mechanisms. Scaffolds with lower RD exhibited higher energy absorption and fracture strain, indicating improved relative toughness. Conversely, increasing IR led to a notable reduction in elastic modulus (E) and failure stress ( , whereas increasing RD enhanced both E and . These results demonstrate that controlled variation of IR and RD enables the design of Voronoi scaffolds with mechanical responses adaptable to both load-bearing and non-load-bearing bone regions.