Computational Mechanics

, Volume 59, Issue 1, pp 147–160

Finite-element analysis of the optical-texture-mediated photoresponse in a nematic strip

  • Hayoung Chung
  • Jung-Hoon Yun
  • Joonmyung Choi
  • Maenghyo Cho
Original Paper

DOI: 10.1007/s00466-016-1340-9

Cite this article as:
Chung, H., Yun, JH., Choi, J. et al. Comput Mech (2017) 59: 147. doi:10.1007/s00466-016-1340-9
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Abstract

In a nematic solid, wherein liquid crystal molecules are incorporated into polymeric chains, the chromophore phase is projected onto the polymer conformation, changing the stress-free configuration metric. Stimulated actuation cannot be separated from the structure itself, since the mesoscopic polymer properties dictate the degree and type of shape change. In this research, we focused on self-deforming device programming, inspired by recent optical techniques, to pattern nontrivial alignment textures and induce exotic strain fields on specimens. A finite-element framework incorporating a light-thermo-order coupled constitutive relation and geometric nonlinearities was utilized to compute mechanical deformations for given external stimuli. The distortion of planar strips into various exotic 3D shapes was simulated, and disclination-defect-like liquid crystal texture topographies with different defect strengths produced various many-poled shapes upon irradiation, as observed experimentally. The effects of the boundary conditions and geometric nonlinearities were also examined, exemplifying the need for a comprehensive finite-element-based framework. The same method was applied to textures naturally emerging due to static distortion, and the effects of the prescribed inhomogeneities on the overall deformations, which is the basis of inverse design, were observed. Furthermore, we analyzed the local Poisson-effect-induced instability resulting from inscribing a hedgehog disclination texture onto a solid; the onset of buckling-like deformations was observed energetically, and the relations between this onset and other physical properties were elucidated to enable microstate design while maintaining structural stability. These results will facilitate the development and comprehension of the mechanisms of remotely light-controlled self-assembly and propulsion systems that may soon be realized.

Keywords

Finite-element analysis Multiphysics Nematic solids Optical textures Smart materials 

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Hayoung Chung
    • 1
  • Jung-Hoon Yun
    • 1
  • Joonmyung Choi
    • 1
  • Maenghyo Cho
    • 1
  1. 1.Multiscale Mechanical Design Division, Department of Mechanical and Aerospace EngineeringSeoul National UniversitySeoulSouth Korea

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