A Stair-Building Strategy for Tailoring Mechanical Behavior of Re-Customizable Metamaterials

Re-customizable mechanical behavior is critical for versatile materials with tunable functions and applications, but inverse design for varying targets is often hindered by complex coupling between structural topologies and mechanics. In this work, a novel "stair-building" strategy for customizing as well as re-customizing target mechanical behavior for mechanical metamaterials is proposed. Similar to building a stair with bricks, customizing or re-customizing a target stress-strain (force-displacement) curve for the material can be realized by stacking the brick-like loading curves of bistable units visually. The mechanical feasibility of the "stair-building" strategy is firstly physically realized in a type of array-structured multistable mechanical metamaterial and then carefully verified by theoretical mechanics analysis. Accordingly, three specific simple design schemes are further proposed for implementation. The "stair-building" strategy is proved to be rapid, effective, and accurate for mechanical behavior customization by both experiments and finite element simulations. Moreover, re-customization for diverse mechanical behaviors in a wide range can be realized by the same piece of metamaterial. This design strategy provides a novel approach for tailoring metamaterials with re-customizable target mechanical behaviors and applies to a variety of bistable units.