MECHANICAL EVALUATION OF VORONOI-CORE SANDWICH STRUCTURES BY ADDITIVE MANUFACTURING

Abstract

This study investigates the mechanical behavior of Voronoi-core sandwich structures fabricated from Tough PLA using FDM. The Voronoi texture generated stochastic, organic-like pores resembling natural open-cell materials. Five core configurations (V0.2–V1.0) were designed with varying pore density while maintaining approximately 33-35 wt% material usage relative to the fully solid reference (V0). Low pore-density specimens with thicker and larger surface-area bridges between pores (e.g., V0.2) outperformed high pore-density specimens with thinner, narrower, lower surface-area walls (e.g., V1.0). In compression, V0.2 achieved the highest modulus (62.94 MPa) and stresses of 2.05 MPa (σ10) and 5.71 MPa (σ50), nearly doubling V1.0. Flexural strength decreased with density (14.7 MPa in V0.2 vs. 5.4 MPa in V1.0), while flexural modulus showed an opposite trend, peaking at 141.2 MPa for V0.8. Impact tests confirmed that V0.2 resisted crack initiation up to 9 inches (2036 mJ), initially as surface indentation, whereas V1.0 failed at 6 inches (1357 mJ). At 25 inches, all porous specimens experienced severe damage, though coarser designs showed more progressive failure. Although weaker than solid V0, Voronoi-core sandwiches demonstrated promising mechanical efficiency at ~33-35 wt% material usage, highlighting their potential as bio-inspired cores for lightweight structural applications.

Keywords

• Voronoi-core
• Sandwich Structures
• PLA-based Materials
• Additive Manufacturing
• Mechanical Properties.

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