A novel design of a diaphragm microactuator prepared for micropump has previously been reported. The composite diaphragm consists of a silicon membrane and a patterned Titanium-Nickel (TiNi) thin film. In order to understand the actuation behavior of the diaphragm, modeling and thermal simulation of the diaphragm microactuator is performed with commercial finite element analysis (FEA) software ANSYS. In this paper, dynamic temperature distributions in thermal cycles are comparatively studied. During the thermal cycles, temperatures at the center and the border of the diaphragm and in the rounding silicon frames are monitored. The influences of the operational parameters such as current and duty ratio on the temperature distributions are quantitatively predicted. The optimal heating condition for the actuation can be inferred from the simulation results. Futhermore, diaphragm deflection profiles and stress distributions are illustrated by coupled thermomechanical analysis based on the thermal analysis. The experimental measurements of the deflection dependence on various power supplies can be explained in terms of the temperature variations in cycles. Finally, optimization of the patterned TiNi resistance strips is also proposed with respect to uniform temperature distribution and maximum deflection.
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