Programmable mechanical metastructures from locally bistable domes

Mechanical metamaterials have introduced a paradigm shift in materials development by offering property control through geometrical design at the micro/mesoscale. The ensuing design flexibility has opened up avenues to leverage geometrical nonlinearities in the microstructure design to allow for realizing uncharacteristic global functionalities beyond the scope of traditional materials. In this work, we report on a class of programmable stiffness metastructures designed by patterning locally bistable dome units in structural element geometries. The global response characteristics of our metastructures reversibly switch between a plate-like response and a shell-like response as the bistable domes are switched locally between their two stable states. This allows for up to an order of magnitude variation in the global stiffness. Furthermore, we demonstrate the ability of our metastructures to enable in-situ property programmability in the presence of boundary conditions, thus paving the way for successful integration into larger structures. Uniquely, our architecture allows for multi-directional linear and nonlinear response programmability, while operating under different loading environments. As such, the presented designs can potentially serve as blueprint models to realize a new class of load-carrying, robust, programmable systems for soft robotics and morphing aerospace structures. (C) 2020 The Authors. Published by Elsevier Ltd.

Automated summary

Mechanical metamaterials offer property control through geometrical design at the micro/mesoscale, enabling global functionalities beyond traditional materials. A class of programmable stiffness metastructures designed by patterning locally bistable dome units demonstrate reversible global response characteristics. These designs could potentially serve as blueprint models for load-carrying, programmable systems in soft robotics and morphing aerospace structures.