A performance metric for additively manufactured microlattice structures under different loading conditions

A rapidly evolving design technology in additive manufacturing is microlattice (or microarchitectured) materials. Investigating the performance of microlattices under different loading conditions is a key element for implementing this new technology into mechanical components used in different industries. In this paper, the mechanical behavior of five different microlattices under four standard modes of loading along with a combined loading scenario was investigated. The four standard modes of loading that were considered are tension, compression, simple shear, and bending. The combined loading scenario was simultaneous shear and compression. The lattice structures (i.e. octet-truss, diamond, pyramid, block lattice truss, and cubic truss) were modeled and meshed using Autodesk Inventor and Fusion 360. Constraints and the elastic loading conditions for the structures were applied to the models in Fusion 360 and static finite element simulations were performed using Autodesk Nastran software. The results of all simulations were collated and a performance function was derived from the maximum stress and stiffness results and mass of the structures. The two highest performing structures (octet-truss and cubic lattice) according to the derived metric were then combined. The octet lattice performed well under shear and the combined loading cases, while the cubic lattice performed well under tension, compression, and bending. Simulations were repeated and the performance metric was then used to show that the combination of these structures, known as the Warren truss, had improved performance as a result.