FEM simulation of the Nitinol wire

In recent years, one of the most promising new actuator technologies is based on the use of Shape Memory Alloys (SMA). The main challenge for the application of devices that use these materials is the hysteresis in the phase transition they suffer during actuation. Finite element analysis (FEA) is an important aid in the simulation of mechanical properties and thermal fields in actuators. Dynamic simulations give in many cases enough information without the necessity of building a prototype. We have used ABAQUS to simulate a Nitinol wire used in a micropositioning actuator. The model parameters, not given by the supplier but required by the FEA program, have been obtained by thermal and mechanical characterization of the material used. The output force is computed and compared with the measurements.