In recent years, shape memory alloys (SMAs) have become widely used in engineering applications due to their simplicity in use and high power density. These smart materials are characterized by their unique temperature dependent phase transformations. An accurate heat transfer model is of the utmost importance for modeling the SMA actuator dynamics. This is due to the SMA constitutive and phase kinetic behaviors being directly dependent on the heat transfer model. The research shown in this paper was conducted to investigate the adequacy of the exiting heat transfer models for SMA wire actuators. Particularly, the convection heat transfer for SMA wires with diameter of a few hundred micrometers is studied. To this end, an SMA wire actuating a dead weight was used to experimentally determine how the heat transfer coefficient varies during transformation at varying levels of applied current. These results are then compared to several existing heat transfer models. In the experiments, the temperature of the wire was measured along with the strain and stress of the SMA wire. A detailed discussion of the theoretical models and experimental findings is presented in this paper.

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