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Title: Emergent perversions in the buckling of heterogeneous elastic strips

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:
 [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Northwestern Univ., Evanston, IL (United States)
  2. Northwestern Univ., Evanston, IL (United States); Simpson Querrey Institute for BioNanotechnology, Chicago, IL (United States)
Publication Date:
OSTI Identifier:
1257284
Grant/Contract Number:
SC0000989
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 26; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Northwestern Univ., Evanston, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; elasticity; perversion; helix; energy concentration; defect