Decoupling Minimal Surface Metamaterial Properties Through Multi‐Material Hyperbolic Tilings

Abstract

Rapid advances in additive manufacturing have kindled widespread interest in the rational design of metamaterials with unique properties over the past decade. However, many applications require multi-physics metamaterials, where multiple properties are simultaneously optimized. This is challenging since different properties, such as mechanical and mass transport properties, typically impose competing requirements on the nano-/micro-/ meso-architecture of metamaterials. Here, a parametric metamaterial design strategy that enables independent tuning of the effective permeability and elastic properties is proposed. Hyperbolic tiling theory is applied to devise simple templates, based on which triply periodic minimal surfaces (TPMS) are partitioned into hard and soft regions. Through computational analyses, it is demonstrated how the decoration of hard, soft, and void phases within the TPMS substantially enhances their permeability-elasticity property space and offers high tunability in the elastic properties and anisotropy at constant permeability. Also shown is that this permeability-elasticity balance is well captured using simple scaling laws. The proposed concept is demonstrated through multi-material additive manufacturing of representative specimens. The approach, which is generalizable to other designs, offers a route towards multi-physics metamaterials that need to simultaneously carry a load and enable mass transport, such as load-bearing heat exchangers or architected tissue-substituting meta-biomaterials.

Volumetric Bioprinting of Organoids and Optically Tuned Hydrogels to Build Liver‐Like Metabolic Biofactories

“…At first, we selected a series of 3D objects with convoluted pore distribution from a pool of mathematically defined triple periodic minimal surface structures. This class of geometries is wellknown in the field of tissue engineering, as lattices belonging to this family have been investigated to produce mechanical metamaterials, [62] to maximize cell seeding in polymeric scaffolds, [63] and to promote in vivo bone ingrowth in biomaterialsbased implants, [64] among other applications. Specifically, we selected three lattice structures with interconnected porosity: Schwarz D, Schwarz G, and Schwarz P. [65][66][67][68] At a comparable volume (between 383.17 and 394.25 mm 3 ), these structures show a decrease in surface area to volume ratio (from 2.05 to 1.88 mm −1 ), and decreasing average tortuosity of the porous network (from 1.32 to 1.04) respectively.…”

A Novel Ultra‐Wideband Electromagnetic‐Wave‐Absorbing Metastructure Inspired by Bionic Gyroid Structures

“…The elastic constitutive model of the metastructure can be calculated using the asymptotic homogenization (AH) method, [42] and the anisotropic index A H is used to evaluate the anisotropy of the structures at different densities (Figure S2, Supporting information). Moreover, the Gibson-Ashby model of two types of gyroid structures is also established, as shown in Figure 1f.…”

Recent Advancements in Design Optimization of Lattice‐Structured Materials

“…Furthermore, partitioning a structure into two phases is a recent technique to produce multimaterial lattice structures. Callens et al [105] applied the hyperbolic tiling theory to generate the primitive and gyroid structures partitioned into hard and soft regions. A triangular tiling on the hyperbolic plane was radially repeated with different angles (i.e., π=2, π=4, π=6) to generate the structures.…”