3D Woven Metamaterials via Additive Manufacturing and Computational Design

Three-dimensional (3D) architected materials (or mechanical metamaterials) provide a pathway to defy the limitations of monolithic materials through their engineered internal microstructures, allowing them to exhibit unique and extreme properties. Thus far, research on the design of these architected materials has been primarily dominated by the quest to achieve extreme stiffness and strength, which limits their applicability in various fields. Unlike conventional truss-based architectures which induce stress concentrations and fail at strains lower than their constituent material, compliant woven architectures have recently been demonstrated to be able to sustain large tensile strains (several times larger than its constituent). However, the complex mechanics of woven architectures remain to be fully understood, and substantial bottlenecks exist in their design.<br/>Here, we provide a computational design framework for woven metamaterials that allows for spatial variation of fiber- and lattice-level parameters, allowing rapid generation of functionally graded metamaterials that can be additively manufactured at the micron scale and beyond. Variation of parameters at the sub-unit-cell level (on individual truss elements) greatly extends the design space and facilitates new modeling methods for these materials. Through reducing the lattice to a graph representation in order to create the weave topology, we facilitate the creation of woven architected materials with tailorable mechanical properties. Using this design framework, we present two modeling routes (high-fidelity and reducer-order) to quantify the architecture-dependent nonlinear properties, attributing contributions to nonlinear material properties and frictional contact. Through <i>in situ </i>micro-tension experiments to validate our models, we demonstrate that hybrid woven architectures can not only exhibit higher stiffness (more than an order of magnitude) than pure woven architectures, but also attain higher dissipated energy densities than the sum of their counterparts. This work aims to provide a pathway for the design of compliant metamaterials—with arbitrary tunability—via an integrated computational design and modeling framework geared for production via additive manufacturing.