Effects of director rotation relaxation on viscoelastic wave dispersion in nematic elastomer beams

Abstract

In this paper, the transverse wave dispersion in a nematic elastomer (NE) Timoshenko beam is studied by considering anisotropy and viscoelasticity of NEs in the low frequency limit. Firstly, the characteristic equations of wave motion in an NE beam are derived, and then numerically solved to obtain the corresponding phase velocities and attenuation factors. The influences of anisotropic parameter, director rotation and rubber relaxation times on the wave dispersion in an NE beam are discussed. Results show that unlike the situation in general isotropic viscoelastic beam, non-classical viscoelastic wave dispersion is found in NE beams. Geometric dispersion is restrained with the vanishing of cut-off frequencies for shear waves due to director rotation relaxation of NEs. This unique property promises prospective applications of NE beams in optic or acoustic design.

Self-Vibration of a Liquid Crystal Elastomer Fiber-Cantilever System under Steady Illumination

“…In this section, we first propose a light-powered self-oscillation system containing an LCE fiber, an oblique bending cantilever, and a mass block. Then, we present a theoretical model for the self-oscillation system based on the dynamic LCE model [ 8 ] and beam theory [ 73 ]. The dynamic control equations of the system, the evolution law of the cis number fraction in LCE, and the nondimensionalization of the system parameters are then given in turn.…”

Theoretical Analysis of Light-Actuated Self-Sliding Mass on a Circular Track Facilitated by a Liquid Crystal Elastomer Fiber

“…Considering the advantageous characteristics of light, there is a wide range of self-vibrating systems enabled by light-actuated liquid crystal elastomers (LCEs), encompassing actions like bending [ 47 , 48 ], synchronization [ 49 ], rolling [ 50 , 51 ], shuttling [ 52 ], jumping [ 31 ], flying [ 53 ], floating [ 16 ], swimming [ 22 ], spinning [ 54 ], chaos [ 55 , 56 ], and various other self-vibration mechanisms. Light-responsive LCEs exhibit extensive applicability and broad prospects in the fields of micro robots [ 57 , 58 , 59 ], biomimetic soft robots [ 60 , 61 , 62 , 63 ], biomedicine [ 64 ], and energy harvesting [ 65 ], due to their reversible contraction [ 66 ] and relaxation properties [ 67 , 68 ] under light stimuli.…”