Addressing manufacturing defects in architected materials via anisotropy: minimal viable case

Abstract

The emergence of additive manufacturing has enabled the fabrication of architected materials with intricate micro- and nanoscale features. However, each fabrication method has a specific minimum feature size that can be practically achieved. As engineers pursue lightweight and high-performance materials, the elements of these architected materials often approach this minimum feature size, which poses a risk to their structural integrity. The failure of individual struts can result in the complete breaking of the lattice metamaterial’s connectivity or, depending on the internal architecture, only a marginal reduction in its load-bearing capacity. In this short letter, we use a minimal viable unit cell to demonstrate how an anisotropic lattice, constructed with beams of varying thicknesses, can surpass a lattice consisting solely of uniform thickness beams in terms of damage tolerance. Our focus is primarily on the manufacturing limitations rather than defects that may arise during the loading of architected materials. We propose an approach where the probability of each individual strut failure depends on its thickness, and we illustrate the implications using a simple step-like function. This approach can be extended to more complex metamaterials or to explore intricate relationships between failure probability and beam thickness.