Dynamic response of a simply supported liquid-crystal elastomer beam under moving illumination

Optically responsive liquid crystal elastomer (LCE) devices have thriving potential to flourish in soft robots and microdrives, owing to their advantages of remote controllability, structural simplicity, and no power supply. In terms of illumination-driven modes, most research has focused on the dynamic response of LCE devices under continuous and periodic illumination, while the theoretical study of the dynamic response under moving illumination is limited. In this paper, based on the coupling of LCE and mechanical deformation under moving illumination, the dynamic model of a LCE simply supported beam is built to investigate its dynamic response under moving illumination. The analytical solution of the dynamic response of the LCE beam under moving illumination is derived through the modal superposition method and the Duhamel integration, and the solution is programed and analyzed with matlab software. By numerical calculations, the influence of the internal and driving parameters of the structure on the dynamic response of the LCE simply supported beam can be analyzed. The results show that when the moving speed of illumination reaches the first-order critical frequency, the maximum amplitude of the dynamic response at the beam mid-span will reach a peak. Meanwhile, the dynamic response of beam can be improved by increasing the illumination width, increasing the light intensity, increasing the shrinkage coefficient, and reducing the damping coefficient. This work provides theoretical guidance for applying the dynamic response of LCE devices under moving illumination in soft robots, microactuators, energy harvesters, sensors, etc.