Bio-inspired selective nodal decoupling for ultra-compliant interwoven lattices

Abstract

Architected materials such as lattices are capable of demonstrating extraordinary mechanical performance. Lattices are often used for their stretch-dominated behavior, which gives them a high degree of stiffness at low-volume fractions. At the other end of the stiffness spectrum, bending-dominated lattices tend to be more compliant and are of interest for their energy absorption performance. Here, we report a class of ultra-compliant interwoven lattices that demonstrate up to an order of magnitude improvement in compliance over their traditional counterparts at similar volume fractions. This is achieved by selectively decoupling nodes and interweaving struts in bending-dominated lattices, inspired by observations of this structural principle in the lattice-like arrangement of the Venus flower basket sea sponge. By decoupling nodes in this manner, we demonstrate a simple and near-universal design strategy for modulating stiffness in lattice structures and achieve among the most compliant lattices reported in the literature.