Title: Emergent perversions in the buckling of heterogeneous elastic strips

Abstract

A perversion in an otherwise uniform helical structure, such as a climbing plant tendril, refers to a kink that connects two helices with opposite chiralities. Such singularity structures are widely seen in natural and artificial mechanical systems, and they provide the fundamental mechanism of helical symmetry breaking. However, it is still not clear how perversions arise in various helical structures and which universal principles govern them. As such, a heterogeneous elastic bistrip system provides an excellent model to address these questions. In this paper, we investigate intrinsic perversion properties which are independent of strip shapes. This study reveals the rich physics of perversions in the 3D elastic system, including the condensation of strain energy over perversions during their formation, the repulsive nature of the perversion–perversion interaction, and the coalescence of perversions that finally leads to a linear defect structure. Finally, this study may have implications for understanding relevant biological motifs and for use of perversions as energy storers in the design of micromuscles and soft robotics.

Authors:

Liu, Shuangping ^[1]; Yao, Zhenwei ^[1]; Chiou, Kevin ^[1]; Stupp, Samuel I. ^[2]; Olvera de la Cruz, Monica ^[3]

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+ Show Author Affiliations

1. Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208-3108,
2. Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208-3108,, Department of Chemistry, Northwestern University, Evanston, IL 60208-3108,, Department of Medicine, Northwestern University, Chicago, IL 60611,, Simpson Querrey Institute for BioNanotechnology, Chicago, IL 60611,
3. Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208-3108,, Department of Chemistry, Northwestern University, Evanston, IL 60208-3108,, Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208-3108,, Department of Physics, Northwestern University, Evanston, IL 60208-3108

Publication Date:

Tue Jun 14 00:00:00 EDT 2016

Research Org.:

Northwestern Univ., Evanston, IL (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Bio-Inspired Energy Science (CBES)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1257284

Alternate Identifier(s):

OSTI ID: 1347965

Grant/Contract Number:  

SC0000989

Resource Type:

Published Article

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 113 Journal Issue: 26; Journal ID: ISSN 0027-8424

Publisher:

Proceedings of the National Academy of Sciences

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; elasticity; perversion; helix; energy concentration; defect