Bi-Directional Origami-Inspired SMA Folding Microactuator

Language
en
Document Type
Article
Issue Date
2021-09-13
First published
2021-08-03
Issue Year
2021
Authors
Seigner, Lena
Tshikwand, Georgino Kaleng
Wendler, Frank
Kohl, Manfred
Editor
Publisher
MDPI
Abstract

We present the design, fabrication, and characterization of single and antagonistic SMA microactuators allowing for uni- and bi-directional self-folding of origami-inspired devices, respectively. Test devices consist of two triangular tiles that are interconnected by double-beam-shaped SMA microactuators fabricated from thin SMA foils of 20 µm thickness with memory shapes set to a 180° folding angle. Bi-directional self-folding is achieved by combining two counteracting SMA microactuators. We present a macromodel to describe the engineering stress–strain characteristics of the SMA foil and to perform FEM simulations on the characteristics of self-folding and the corresponding local evolution of phase transformation. Experiments on single-SMA microactuators demonstrate the uni-directional self-folding and tunability of bending angles up to 180°. The finite element simulations qualitatively describe the main features of the observed torque-folding angle characteristics and provide further insights into the angular dependence of the local profiles of the stress and martensite phase fraction. The first antagonistic SMA microactuators reveal bi-directional self-folding in the range of −44° to +40°, which remains well below the predicted limit of ±100°.

Journal Title
Actuators
Volume
10
Issue
8
Citation

Actuators 10.8 (2021): 181. https://www.mdpi.com/2076-0825/10/8/181

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