Shape memory alloy (SMA) actuators can be heated quickly using electrical resistance heating. However, the slow cooling of the SMA actuator limits the actuation frequency. Therefore, the current research was undertaken to increase the actuation frequency by making a SMA heat pipe. The heat pipe is a hollow NiTi SMA cylinder partially filled with a wick and water. The condenser end of the pipe is maintained at 5C. The evaporator was cycled between a temperature below Ms and above As by adding electrical current when necessary. A pipe partially filled with water cycled faster than both a dry pipe and a fully filled pipe. Thus, the heat pipe allows for faster cycling of SMA actuators with no need for complicated or moving parts. However, the heat pipe works best with a constant temperature difference between the evaporator and the condenser, whereas the SMA must cycle. Therefore, the heat pipe is best suited to SMA materials with a small difference between the Mf and the Af temperatures.
