A nonlinear bending theory for nematic LCE plates

Abstract

In this paper, we study an elastic bilayer plate composed of a nematic liquid crystal elastomer in the top layer and a nonlinearly elastic material in the bottom layer. While the bottom layer is assumed to be stress-free in the flat reference configuration, the top layer features an eigenstrain that depends on the local liquid crystal orientation. As a consequence, the plate shows non-flat deformations in equilibrium with a geometry that non-trivially depends on the relative thickness and shape of the plate, material parameters, boundary conditions for the deformation, and anchorings of the liquid crystal orientation. We focus on thin plates in the bending regime and derive a two-dimensional bending model that combines a nonlinear bending energy for the deformation, with a surface Oseen–Frank energy for the director field that describes the local orientation of the liquid crystal elastomer. Both energies are nonlinearly coupled by means of a spontaneous curvature term that effectively describes the nematic-elastic coupling. We rigorously derive this model as a [Formula: see text]-limit from three-dimensional, nonlinear elasticity. We also devise a new numerical algorithm to compute stationary points of the two-dimensional model. We conduct numerical experiments and present simulation results that illustrate the practical properties of the proposed scheme as well as the rich mechanical behavior of the system.

Liquid Crystal Orientation and Shape Optimization for the Active Response of Liquid Crystal Elastomers

“…Normally, S is controlled by an external actuation mechanism, e.g., thermal, cf. [36,46]. Without loss of generality, we have omitted such dependence, i.e., S evolves by a prescribed update strategy.…”

“…To model this phenomena, LCE continuum material models use a scalar-or tensor-order parameter to quantify the alignment of the LCE mesogens. Such models have been validated for both small-and large-strain deformations resulting from a variety of loadings, e.g., thermal and light [44][45][46][47].…”