Cover Page
The handle http://hdl.handle.net/1887/44437 holds various files of this Leiden University dissertation
Author: Florijn, H.C.B.
Title: Programmable mechanical metamaterials Issue Date: 2016-11-29
Promotor: Prof. dr. M.L. van Hecke
Promotiecommissie: Dr. J.T.B. Overvelde (AMOLF, Amsterdam) Dr. P. Reis (MIT, Cambridge, USA)
Prof. dr. J. Aarts Prof. dr. E.R. Eliel Prof. dr. H. Schiessel Prof. dr. V. Vitelli
Casimir PhD series, Delft-Leiden 2016-31 ISBN 978-90-8593-275-8
The work described in this thesis is funded by the Netherlands Or- ganization for Scientific Research through a VICI grant, NWO- 680-47-609.
Cover design by Niels Peereboom
"Je gaat het pas zien als je het doorhebt."
H.J. Cruijff
Voor mijn familie
Contents
1 Introduction 1
1.1 Optical Metamaterials . . . . 1
1.2 Thermal Metamaterials . . . . 3
1.3 Mechanical Metamaterials . . . . 4
1.3.1 Linear Material Properties . . . . 5
1.3.2 Nonlinear Mechanical Metamaterials . . . . 6
1.4 This Thesis . . . . 9
2 A Programmable Mechanical Metamaterial 11 2.1 Introduction . . . 12
2.2 Samples . . . 14
2.2.1 Molds . . . 15
2.2.2 Molding . . . 18
2.2.3 Sheet Preparation: Cutting, Gluing and Clamping . . 19
2.2.4 Material Properties . . . 23
2.3 Experimental Methods . . . 27
2.3.1 Parameters . . . 27
2.3.2 Experimental setup . . . 29
2.3.3 Experimental Protocol . . . 31
2.3.4 Image analysis . . . 33
2.4 Programmable Mechanical Response . . . 34
2.5 Numerics . . . 38
2.6 Soft Mechanism . . . 40
2.7 Conclusion . . . 41
3 Soft Mechanism 43 3.1 Biholar Mechanism . . . 44
3.2 Energy, Stability and Bifurcations . . . 45 i
CONTENTS
3.3 Geometrical Interpretation . . . 53
3.4 Conclusions . . . 62
A Derivation of the Mechanics of the Biholar Soft Mechanism us- ing Lagrange Multipliers 63 4 Programmable Mechanical Metamaterials: the Role of Geometry 65 4.1 Introduction . . . 66
4.2 Samples and Experimental Methods . . . 67
4.3 Numerical Simulations . . . 69
4.4 Experimental and Numerical Results . . . 71
4.4.1 Phenomenology . . . 71
4.4.2 Order Parameters . . . 74
4.5 Parametric Study . . . 79
4.6 Variation of strain ranges with geometric parameters . . . . 81
4.7 Conclusion . . . 86
B Role of Clamp Size 87 5 Barcode Metamaterial 89 5.1 Motivation . . . 90
5.2 Programmable mechanics by position of the clamps . . . 91
5.3 Homogenous confinement of large biholar systems . . . 100
5.3.1 9×10 holes . . . 100
5.3.2 8×10 holes . . . 108
5.4 Controlling the domain walls . . . 116
5.5 Example of Barcode Programming . . . 118
5.6 Conclusion . . . 121
Summary 131
Samenvatting 135
Publication List 139
Curriculum Vitae 141
Acknowledgments 143
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