ON THE ROLE OF THERMOELECTRIC HEAT TRANSFER IN THE DESIGN OF SMA ACTUATORS: THEORETICAL MODELING AND EXPERIMENT By

A combined theoretical/experimental study of the heat transfer in thermoelectric Shape Memory Alloy (SMA) actuators is undertaken in this paper. A one-dimensional model of a thermoelectric unit cell with a SMA junction is developed rst and the transient temperatures in the SMA are evaluated for di erent applied electric current densities. As a rst step towards the design of an actuator, a thermoelectric module is assembled in the laboratory for cooling/heating the SMA. Transient temperature pro les are recorded for the monotonic heating and cooling runs for two di erent materials copper and SMA (with or without the phase transformation). These recorded pro les are then compared with the predictions from the model; the agreement is reasonable, particularly during the cooling process. Temperature pro les are also recorded for cyclic cooling and heating of copper at a frequency of 0.5 Hz and a good comparison is obtained. Theoretical predictions for thermal cycling of SMA show that it is possible to achieve a frequency of 2 Hz on full phase transformation and 17 Hz on partial transformation of 25%.