Exploring the design space of the effective thermal conductivity, permeability, and stiffness of high-porosity foams

Abstract

With knowledge of only a few effective properties of a porous structure, the applicability of the structure for a given system can quickly be determined. This study numerically simulates the effective thermal conductivity, permeability, and stiffness of high porosity structures. Commonly used isotropic architected porous structures are compared with commercially available stochastic metal foams. The architected structures include body-centered cubic (BCC) lattice, shell-based triply periodic minimal surface (TPMS), and hybrid foam (HF) composed of beam and shell with multiple adjustable parameters. The simulated effective properties touch on the applicability in heat transfer, fluid flow, and mechanically stressful situations. The dimensionless effective properties of the structures are presented in graphical form to clearly illustrate structurally dependent properties. Compared to the stochastic metal foams, the architected structures (BCC, TPMS, and most HF) showed higher effective thermal conductivities and permeabilities. This indicates a potential to improve the efficiency of a thermal or fluid flow system by replacing the stochastic foam with architected foam. Additionally, the HF structure shows broad tunability of specific properties. All effective properties simulated were rendered dimensionless to only reflect the impact of topology, and plotted in charts to show trends. These charts can aid in the selection of porous structures in diverse applications.