Additive Manufacturing and Mechanics of Mathematically-generated Meta-structures

Abstract

Advancements in additive manufacturing coincide with the influx of assiduous research in realizing complex structures using printable composite materials with tunable properties. In this research, photocurable resins with a broad range of mechanical properties were hybridized with ceramic particles to alter the overall response. The newly formulated printable resins comprised up to 20 wt.% glass microballoons, balancing between the tunability of the composite properties and manufacturability. The compressive and tensile bulk properties were first assessed using additively manufactured samples tested under quasi-static loading. Supplementary digital image correlation (DIC) was used to resolve the strain fields, revealing insights about the mechanical behavior and failure modes as a function of reinforcement weight ratio. Despite the expected hyperelastic constitutive behavior and shared macromolecular composition, the neat and hybridized photocurable resins exhibited distinctive mechanical behavior, leading to the characterization of the dynamic properties as a function of temperature to ascertain the underpinnings of respective responses. To demonstrate the utility of newly formulated printable composite resins, triply periodic minimal surface (TPMS) structures were also manufactured using the vat photopolymerization approach. The printed structures were tested under compression at a quasi-static loading rate. The DIC-resolved strains revealed the underlying structural mechanics as a function of the material properties. This case study correlates the mechanics governing particulate-reinforced elastomers with the observed variations in strain development, stiffness, load-bearing capacity, and specific energy absorption for TPMS structures. The outcomes of this research reveal the potential for tunable, 3D printed sports gear for impact mitigation in various biomechanical loading conditions.