This paper presents a study of the mechanical and thermal properties of SMA microvalves, which are driven by a microactuator of a NiTi foil or a Ni 2MnGa thin film. By coupled finite element simulations, von Mises stress profiles and resulting actuation forces are determined, which are compared with experimental force-displacement characteristics. The relatively high phase transformation temperatures of the used Ni2MnGa specimens Mf / Af of 92 / 125°C, give rise to cooling times of about 25 ms compared to 90 ms for NiTi. Thus, Ni2MnGa microvalves show a superior switching performance. However, due to brittleness and buckling instability, Ni2MnGa microvalves only allow a maximum controllable pressure difference of 70 kPa, which is more than a factor of 7 smaller compared to NiTi microvalves.
|Number of pages||10|
|Journal||Journal De Physique. IV : JP|
|Publication status||Published - 2004 Dec 1|
|Event||EUROMECH-MECAMAT'2003: 7th European Mechanics of Materials Conference on Adaptive Systems and Materials: Constitutive Materials and Hybrid Structures - Frejus, France|
Duration: 2003 May 18 → 2003 May 23
ASJC Scopus subject areas
- Physics and Astronomy(all)