Multiscale Computational Model of Soft Elasticity and Director Reorientation in Nematic Gels

Abstract

A coarse-grained model of soft elasticity of nematic elastomers is presented, in which fine-scale spatial oscillations are carefully accounted for in the definition of an effective energy density, and then averaged out from the kinematics. Algorithmically, this amounts to taking a suitable convex envelope of the original free-energy of the system. The resulting finite element simulations of stretching experiments on thin sheets of nematic elastomers enable us to resolve simultaneously the macroscopic mechanical response (e.g., deformed shape, stress-strain curves) and the underlying microscopic mechanisms (e.g., evolution of domain structures, local reorientation of the nematic director).