A note on size effect in actuating NiTi shape memory alloys by electrical current

The size effect in triggering the actuation of NiTi shape memory alloys directly by electrical current is investigated. Wire/rod is taken as an example in this study to show the relationship between the diameter of shape memory alloy wire/rod and the required current/power for actuation, and in the case of cyclic operation, achievable frequency. Through a few case studies, it is revealed that by presenting on logarithmic scale, the major operating characteristics can be quickly estimated as linear functions of wire/rod diameter.