Transient heat transfer behavior of one-dimensional symmetric thermoelectric SMA actuators

The main purpose of this paper is to study the transient heat transfer behavior of one-dimensional symmetric thermoelectric Shape Memory Alloy (SMA) actuators, without assuming a small ratio between the layer thicknesses of SMA and semiconductor. For the transient heat transfer with a constant current density, it is proved that there is an upper bound for the current density so that the temperature distribution along the SMA layer is stable. For the transient cooling problem with a constant current density, it is proved that there is a lower bound for the current density so that the temperature at the interface between SMA and semiconductor layers is always decreasing to its stable state, and it may not be always decreasing if the current density is below the lower bound. Estimates for these bounds are derived. The physical implications of main results are also discussed.