Investigation of Triply Periodic Minimal Surfaces in Comparison to Honeycomb for Aerospace Application

Abstract

Optimizing structures into a lattice can lead to efficient designs with highly desired properties. In aerospace applications, Honeycomb lattice structures are used for lightweighting purposes. Honeycomb is easy to manufacture out of a variety of materials but has anisotropic properties. Due to this, other types of cores for sandwich composites could be used investigated for lightweighting purposes. Triply Periodic Minimal Surfaces (TPMS) are structures that can only be manufactured using 3D printing. The Gyroid, Schwarz Primitive (Primitive) and Schwarz Diamond (Diamond) lattice structures were chosen to compare to Honeycomb for aerospace applications due to their isotropic nature. The models were parameterized in SolidWorks and evaluated in Ansys. The Diamond lattice was eliminated for comparison in the simulation process. The SLA printing process was chosen as the material to compare the remaining samples due to its high-resolution capabilities. Each sample was evaluated in compression and was tested five times and averaged for statistical significance. Honeycomb was tested in two directions due to the anisotropic property. Both the Axial and Transverse directions were tested five times and averaged for statically significance. The compression strength of each lattice was normalized by the average sample density. The results show the Gyroid with a strength-to-density of 5.692, the Primitive with a ratio of 5.182, the Honeycomb Axial with a ratio of 26.144, and the Honeycomb Transverse with a ratio of 1.008, all in N/(kg/m^3). These results clearly indicate that Honeycomb is best in the axial direction when uniaxially loaded. For other applications where the load paths vary in multiple directions, such as a truss on a truss-braced wing, the Gyroid may be a better option due to the isotropic nature of the structure.