Integrated Design and Simulation of Tunable, Multi-State Structures Fabricated Monolithically with Multi-Material 3D Printing [1]

[1] Chen, T., Mueller, J., Shea, K., (2017) Scientific Reports, https://www.nature.com/articles/srep45671

Table of Content : Abstract | Video | Description | News articles

Abstract

Multi-material 3D printing has created new opportunities for fabricating deployable structures. We design reversible, deployable structures that are fabricated flat, have defined load bearing capacity, and multiple, predictable activated geometries. These structures are designed with a hierarchical framework where the proposed bistable actuator serves as the base building block. The actuator is designed to maximise its stroke length, with the expansion ratio approaching one when serially connected. The activation force of the actuator is parameterised through its joint material and joint length. Simulation and experimental results show that the bistability triggering force can be tuned between 0.5 and 5.0 N. Incorporating this bistable actuator, the first group of hierarchical designs demonstrate the deployment of space frame structures with a tetrahedron module consisting of three active edges, each containing four serially connected actuators. The second group shows the design of flat structures that assume either positive or negative Gaussian curvature once activated. By flipping the initial configuration of the unit actuators, structures such as a dome and an enclosure are demonstrated. A modified Dynamic Relaxation method is used to simulate all possible geometries of the hierarchical structures. Measured geometries differ by less than 5% compared to simulation results.

Video

Project description

In this project, we create designs that reconfigure from a flat sheet to doubly-curved surfaces. Using bistability, we ensure that in the activated state, the structures are structurally stable without additional support. These sheets are fabricated with a commercial multi-material 3D printer.

3D Printed Bistable Actuator

The proposed bistable actuator is able to extend or contract by 50% individually. This ratio approaches 100% when tiled sequentially. It uses a compliant material at the hinges to achieve a rotation of 90 degrees.

Activation of the multi-stable structures

By hierarchically tiling the bistable actuators, we are able to design, simulate and fabricate a number of these structures as show below. The simulation is done using Dynamic Relaxation.

News Articles (12)

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ETH Zurich News (English)
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Die vierte Dimension in der Fertigungstechnik
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2017
ETH Zurich Researchers Develop Load-Bearing 4D Printed Structures
3D Printing
2017
Eth zurich demonstrates self-assembling 4d printed "deployable and active" trusses
3D Printing Industry
2017
Watch 4D-printed object become a sturdy dome - Futurity
Futurity
2017
Fabrication technology in the fourth dimension
EurekAlert!
2017
Neues Verfahren ermoeglicht Drucken in der vierten Dimension
APA (German)
2017
Die vierte Dimension in der Fertigungstechnik
Informationsdienst Wissenschaft (German)
2017
Die vierte Dimension in der Fertigungstechnik
Jura Forum (German)
2017
Arrivano le stampanti 4D: gli oggetti potranno cambiare forma nel tempo
La Repubblica (Italian)
2017