Study Of The Self-sustained Motion Behavior Of An Optically Responsive Liquid Crystal Elastomer Pendulum

Liquid crystal elastomers(LCEs)are polymers formed from cross-linked liquid crystal monomer molecules with good thermal and optical sensing properties,based on which they have attracted the attention of many researchers and have been applied in the study of self-sustained motion.Self-sustained motion is a non-decaying motion with unique advantages,such as obtaining energy directly from the environment,achieving periodic motion without additional human control,widely used for motion actuation of active machines,reducing system complexity and achieving accessibility.Although some self-sustained motion modes and applications of liquid crystal elastomer materials have been investigated,these are not sufficient to meet the requirements of various potential applications.The pendulum system is one of the most classical models studied.Current research has focused on small-amplitude selfsustained oscillations of pendulums,while large-amplitude self-sustained oscillations and self-sustained rotations of pendulums and their applications as actuators have not been explored.In Chapter 2,the dynamics of the large-amplitude self-sustained motion of the photo-thermal effect LCE pendulum is studied theoretically.Through theoretical modeling and numerical calculations,it is found that it can convert the light energy in the environment into thermal energy in the system to cause the pendulum deformation and trigger the self-oscillation and self-rotation of the pendulum.It is concluded that adjusting the illumination area,light intensity,damping coefficient and gravitational acceleration can control the motion state,amplitude and period of the LCE pendulum.In Chapter 3,the self-sustained motion behavior of the photoelastic LCE pendulum is investigated by making improvements on the system of photo-thermal responsive pendulum system.The nonlinear dynamics model of the light-driven motion of the optimized LCE pendulum is presented.The results show that the initial angle,light angle,damping coefficient,light intensity and acceleration can regulate and control the pendulum from rest to oscillation and from oscillation to rotation.In Chapter 4,the dynamics of a single pendulum as a optical driven trolley is innovatively investigated.The mechanism of the self-sustained motion of the pendulum and the cart is illustrated by constructing a dynamical model of a rotating pendulum driving the cart forward.Using the LCE pendulum as the driving system,the stable illumination as the energy input,and the self-excited motion of the pendulum as the driving force,it is concluded that the single pendulum rotation promotes the trolley advance,and the light-driven advance of the trolley can be realized.The self-sustained motion of the LCE single pendulum and the single pendulumdriven trolley proposed in the article has more potential applications in sensing,energy harvesting and motion driving of active machinery.Figure [39] table [2] reference [86]...