Design and mechanical characterization of novel hierarchical dual-zone lattice structures for biomimetic bone scaffolds.

چکیده اصلی

This study presents the design and mechanical evaluation of a novel bone-mimicking hierarchical lattice structure. A cylindrical specimen (20 mm diameter × 20 mm height) was partitioned into two concentric regions to emulate the heterogeneity of natural bone: a solid inner core (10 mm diameter) and an outer annular region (10-20 mm). Distinct cylindrical lattice architectures were assigned to each region using nTopology software. To introduce hierarchical complexity, rectangular lattice structures were embedded within the cylindrical lattice walls of the inner region, while the outer annulus maintained a conventional cylindrical lattice morphology. Lattice topologies (G, D, L, and S types) and arc counts (2 and 4) were systematically varied based on a Taguchi design of experiments (DOE), enabling controlled investigation of topology combinations and geometric parameters. All specimens were additively manufactured and tested under uniaxial compression. Mechanical performance was assessed in terms of first peak stress, energy absorption, and specific energy absorption. Deformation behavior and failure mechanisms were qualitatively analyzed in-situ imaging at consistent displacement intervals. Additionally, density-dependent elastic properties were interpreted using the Gibson-Ashby model to establish structure-property relationships. Results indicate that hierarchical dual-zone lattice configurations emulate the mechanical heterogeneity of natural bone, offering highly tunable energy absorption and promoting stable, progressive collapse. The integration of inter-regional topology variation with intra-wall hierarchical design offers an effective approach for tailoring mechanical response and functional performance. These results demonstrate the potential of the proposed framework for tailoring mechanical properties, and surface area characteristics in lattice structures for biomimetic bone scaffolds.

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