2D Lattice Materials for Actuation

Abstract

Externally triggered lengthening or shortening (actuation) of one or more members in a lattice material can be used to achieve macroscopic shape changes. The three main attributes looked for in 2D lattice materials to be deemed suitable for actuation are in-plane isotropy, high specific elastic properties and limited energy requirement for actuation. However, no infallible topological criteria have yet been discovered that determine which micro-architectures meet these requirements. The Kagome micro-architecture yields the best-performing lattice material for actuation known to date.

This thesis contributes to the search for micro-architectures that perform similar to Kagome lattice material, or even outperform it. Four novel micro-architectures are introduced. Each of the new micro-architectures is verified to constitute a stiff (i.e. stretching-dominated) isotropic lattice material. Still, not all of them result in optimal elastic moduli. One of the proposed designs does perform identically to the Kagome structure in terms of elastic moduli. Moreover, it requires less energy for actuation in the range of relative densities of interest. On the other hand, its attenuation distance is shorter; actuation deformations damp out within a shorter distance than in Kagome lattice material.