Effects of stripe domains on the loading-unloading hysteretic behavior of monodomain nematic elastomers

Abstract

The stress-director coupling of monodomain nematic elastomers may lead to soft deformation and the appearance of stripe domains under uniaxial tension. Based on a continuum mechanical model and finite element method, we investigated the loading-unloading hysteretic behavior of thin monodomain nematic elastomer sheets. Under orthogonal uniaxial loading tests, stripe domains appeared in the center of the specimens after the critical strain was reached. Furthermore, a stress peak was observed, which was followed by a stress plateau. During unloading, these stripe domains did not disappear, and the unloading curve was significantly lower than the loading curve, resulting in large stress-strain hysteresis and unloading residual strain. Additionally, the presence of stripe domains led to an increased strain rate correlation in stress-strain curves, while significantly extending the period of strain recovery without unloading constraints.