Shape Morphing Metamaterials

TL;DR

This review paper discusses the current state, classification, and design principles of shape-morphing mechanical metamaterials, emphasizing their potential across various technological fields.

Contribution

It provides a unified classification system for shape-morphing mechanisms and explores design principles and tools for developing these advanced materials.

Findings

Classification of mechanisms based on anisotropy and internal rotations

Identification of tessellation approaches: kinematic compatibility and geometric frustration

Discussion of design tools and emerging challenges in the field

Abstract

Mechanical metamaterials leverage geometric design to achieve unconventional properties, such as high strength at low density, efficient wave guiding, and complex shape morphing. The ability to control shape changes builds on the complex relationship between geometry and nonlinear mechanics, and opens new possibilities for disruptive technologies across diverse fields, including wearable devices, medical technology, robotics, and beyond. In this review of shape-morphing metamaterials, we examine the current state of the field and propose a unified classification system for the mechanisms involved, as well as the design principles underlying them. Specifically, we explore two main categories of unit cells-those that exploit structural anisotropy or internal rotations-and two potential approaches to tessellating these cells: based on kinematic compatibility or geometric frustration. We conclude by discussing the available design tools and highlighting emerging challenges in the development of shape-morphing metamaterials.