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Published February 4, 2020 | Supplemental Material + Published
Journal Article Open

Guided transition waves in multistable mechanical metamaterials


Transition fronts, moving through solids and fluids in the form of propagating domain or phase boundaries, have recently been mimicked at the structural level in bistable architectures. What has been limited to simple one-dimensional (1D) examples is here cast into a blueprint for higher dimensions, demonstrated through 2D experiments and described by a continuum mechanical model that draws inspiration from phase transition theory in crystalline solids. Unlike materials, the presented structural analogs admit precise control of the transition wave's direction, shape, and velocity through spatially tailoring the underlying periodic network architecture (locally varying the shape or stiffness of the fundamental building blocks, and exploiting interactions of transition fronts with lattice defects such as point defects and free surfaces). The outcome is a predictable and programmable strongly nonlinear metamaterial motion with potential for, for example, propulsion in soft robotics, morphing surfaces, reconfigurable devices, mechanical logic, and controlled energy absorption.

Additional Information

© 2020 National Academy of Sciences. Published under the PNAS license. Edited by Huajian Gao, Nanyang Technological University, Singapore, and approved December 27, 2019 (received for review August 1, 2019). PNAS first published January 22, 2020. We acknowledge support from the US Army Research Office through Award W911NF-17-1-0147. A.R. acknowledges support from Swiss National Science Foundation through Grant P3P3P2-174326. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the US government. The US government is authorized to reproduce and distribute reprints for government purposes notwithstanding any copyright notation herein. Data Availability: The data that support the findings of this study are openly available in Figshare under https://doi.org/10.6084/m9.figshare.10048724. Author contributions: K.B. and D.M.K. designed research; L.J., R.K., J.M., A.R., V.T., and D.M.K. performed research; R.K. contributed new reagents/analytic tools; L.J., R.K., J.M., A.R., and D.M.K. analyzed data; and K.B. and D.M.K. wrote the paper. The authors declare no competing interest. This article is a PNAS Direct Submission. Data deposition: All simulation data, scripts, and experimental data are available on Figshare, https://doi.org/10.6084/m9.figshare.10048724.v2. This article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.1913228117/-/DCSupplemental.

Attached Files

Published - 2319.full.pdf

Supplemental Material - pnas.1913228117.sapp.pdf

Supplemental Material - pnas.1913228117.sm01.mp4

Supplemental Material - pnas.1913228117.sm02.mp4

Supplemental Material - pnas.1913228117.sm03.mp4

Supplemental Material - pnas.1913228117.sm04.mp4

Supplemental Material - pnas.1913228117.sm05.mp4


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August 22, 2023
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