Digital Shape-Morphing Thermo-Mechanical Metamaterials

Abstract

There is an ongoing pursuit to develop intelligent mechanical systems with multifunctional capabilities, such as sensing external stimuli, actuating and adapting in response, and processing and storing logical information. Enabling such capabilities opens-up novel avenues to develop autonomous systems in multiple fields including adaptive structures, soft robotics, medical devices, and consumer electronics. Here, we introduce "digital shape-morphing thermomechanical metamaterials (DSTMs)" as a foundation for intelligent mechanical systems capable of sensing thermal and mechanical stimuli, deploying and adapting to the stimuli by shape morphing and performing digital computation. These functionalities are achieved by integrating mechanical metamaterials with temperature-responsive components, modular designs and digital devices. These DSTMs leverage their engineered mechanical behaviors to undergo temperature-induced autonomous deformations, enabling programmable shape morphing and morphology-based computations. We design DSTM unit cells as modular units to achieve programmable shape morphing and customized logic gate constructions for logical operations. Theoretical, numerical and experimental studies are conducted to validate the performance of DSTMs. Logical input storage and digital output realization are achieved through mechanical and thermal processing techniques, enabling the implementation of digital logic gates such as AND, NAND, OR, NOR, XOR, and XNOR. Furthermore, temperature-induced sequential/non-sequential programmable shape morphing, shape recoverability and modal bifurcation functionalities of the DSTMs are demonstrated.