4. Calculation elements for shape memory actuators

4.1 Force-position diagram, temperature setting

An actuator is an element that provides mechanical work by transforming another type of energy. In this case, the latter energy is thermal, and the parameter used is temperature.

Consider, for example, a shape memory alloy wire elongated to the martensitic state by tensile y ₀ and subjected to a constant force F :

• the mechanical work recoverable by heating (memory effect in the presence of force F ) is given by F (y ₀ – y _e ) (figure 15...