Additively Manufactured Bionic Cellular Metamaterials with Controllable Thermal Conductivity-Mathematical Models and...

Bio-inspired cellular metamaterials manufactured using additive manufacturing technologies provide a promising route for controlling thermal transport properties through architecture rather than through the intrinsic properties of the constituent material. This study investigates steady-state heat transfer in open-cell lattice structures comprising 20 different lattice metamaterial specimens representing various classes of cellular architecture. These include Kelvin, auxetic, BCCZ, BCC, cube, Z-cuboctahedron, diamond, FCC, FBCCXYZ, FCCZ, FBCC, G7, isostructure, octahedron, octet structure, rhombohedral dodecahedron, truncated cuboctahedron and truncated cube, all of which are made from polymer materials. The investigated architectures were inspired by functional principles observed in natural cellular systems, including cancellous bone, wood, coral skeletons, and other biological porous materials, where efficient transport processes are achieved through optimized material distribution and interconnected cellular networks. A theoretical model combining conduction through the lattice skeleton, radiative heat transfer within pores and potential convective contributions was developed using homogenization theory and representative volume element analysis. The experiment confirmed the main hypothesis of this study as described by the mathematical model. Experimental validation also confirmed that the homogenization model correctly predicts the thermal conductivity of open-cell lattice structures in highly porous materials with a porosity of around 0.95. The results demonstrate the potential of biomimetic cellular design for the development of lightweight thermal-management materials with programmable thermal transport properties.