| Numéro |
J. Phys. IV France
Volume 115, June 2004
|
|
|---|---|---|
| Page(s) | 333 - 342 | |
| DOI | https://doi.org/10.1051/jp4:2004115039 | |
J. Phys. IV France 115 (2004) 333
DOI: 10.1051/jp4:2004115039
SMA microactuators for microvalve applications
M. Kohl1, Y. Liu1, B. Krevet1, S. Dürr1 and M. Ohtsuka21 Forschungszentrum Karlsruhe, IMT, Postfach 3640, 76021 Karlsruhe, Germany
2 Tohoku University, IMRAM, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
Abstract
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 Ni
2MnGa specimens
M
/ A
of 92 / 125
C, give rise to cooling
times of about 25 ms compared to 90 ms for NiTi. Thus, Ni
2MnGa microvalves
show a superior switching performance. However, due to brittleness and
buckling instability, Ni
2MnGa microvalves only allow a maximum
controllable pressure difference of 70 kPa, which is more than a factor of 7
smaller compared to NiTi microvalves.
© EDP Sciences 2004