Actuated bending of a long cantilevered glassy nematic bilayer strip: failure of the beam model

Abstract

Abstract Cantilevered long glassy nematic bilayer strips bend in response to light, and thus are attractive for actuation applications. The objective of this work is to examine whether the deformation can be predicted by the one-dimensional beam model as in usual practice. To do so, we consider a bilayer with orthogonal director orientations in the upper and lower layers and analyze its bending in the framework of the classical plate theory. We find that the deflection is much larger than that given by the beam model, because the spontaneous bending in the width direction increases the curvature along the long axis. Therefore, the one-dimensional beam model fails to describe the bending behavior of the cantilevered bilayer strips.