This seminar will present a theoretical model for predicting the gas damping of long, rectangular silicon microcantilevers, which are oscillating in an unbounded gaseous medium with the ambient pressures varying over 5 orders of magnitude (1000 > Kn > 0.03). The work is the result of a collaboration with Prof. Alina Alexeenko (AAE). The surrounding gas flow is modeled using a sub—continuum, quasisteady Boltzmann equation with a simplified ellipsoidal statistical Bhatnagar—Gross—Krook (ES—BGK) collision operator. The computational results of the model are used to present a closed—form correlation for gas damping of different microcantilever vibration modes. The correlation is uniformly valid over 5 orders of magnitude of Kn numbers easily spanning the range over the free—molecular, the transition, and the low—pressure slip flow regimes. This presentation, will also compare the predictions of this theoretical model with the detailed experimental data acquired by Ryan Tung through controlled pressure vacuum chamber experiments with silicon microcantilevers vibrating in the fundamental and higher vibration modes. The experiments were recently performed by Ryan Tung in collaboration with Dr. H. Sumali at the Sandia National Laboratories, New Mexico. The agreement between theory and experiments is excellent.
Birck Nanotechnology Building, Room 1001