Effect of Coating on the Continuous Cycle Actuation of Shape Memory Alloy Wires: Analyses and Experiments

Abstract We develop a finite element methodology to characterize the effects of silicone coating on Shape Memory Alloy (SMA) actuators during continuous actuation cycles. Slow cooling rates of thermally actuated SMA actuators have long been a hurdle for their widespread adoption. The use of a thermally conductive silicone coating provides a potential solution that improves cooling rates without much impact on the actuator thermal performance under single actuation. However, the effects of the coating on the thermal performance under cyclic actuation is unexplored. To verify the finite element model results, various thicknesses between 0.2 mm to 2.5 mm of the coating material were applied to 0.5 mm diameter SMA wires using a specially fabricated coating machine. The results of finite element models were first compared with and calibrated against experimentally measured thermal performance for single actuation cycle. Next, the actuation responses of the numerical models of these coated SMA wires are determined for multiple actuation cycles.