Self-galloping of a liquid crystal elastomer catenary cable under a steady temperature field

Abstract

Thermally-driven self-sustained motion allows for direct absorption of heat from a steady temperature field to maintain its own continuous motion, making it a valuable technology for thermal sensors, harvesters, and soft robotics. Exploring a straightforward and durable system that operates with self-sustained motion driven by heat is a formidable challenge. Based on a thin liquid crystal elastomer (LCE) fiber, we propose a thermally-driven self-galloping catenary cable system in this paper. Experiments show that the LCE catenary cable can engage in continuous periodic self-galloping in a steady temperature field with gradient. Combining the well-established dynamic LCE model and catenary theory, the governing equations of the self-galloping LCE catenary cable are established and its dynamics are theoretically investigated. The LCE catenary cable always develops into two motion modes, i.e., static and self-galloping modes, according to numerical calculations. The theoretical predictions are in general agreement with the experimental results. The LCE catenary cable maintains the self-galloping by absorbing thermal energy to offset the damping dissipation. The effects of system parameters on the amplitude, frequency and equilibrium position of the self-galloping are also obtained. This LCE catenary cable has advantages in terms of simple structure, customizable size, minimal requirement for movement space, and flexible adjustment, and it is anticipated to satisfy the demands of actual complex scenarios such as thermal sensors, energy harvesters, and autonomous robots.