In the current study, the effects of Casimir force and squeeze film damping on pull-in instability and dynamic behavior of electrostatically actuated nano and micro electromechanical systems are investigated separately. Linear elastic membrane theory is used to model the static and dynamic behavior of the system for strip, annular and disk geometries. Squeeze film damping is modeled using nonli...

Squeeze-film damping plays a significant role in the performance of micro-resonators because it determines their quality factors. Perforations in microstructures are often used to control the squeeze-film damping in micro-resonators. To model the perforation effects on the squeeze-film damping, many analytical models have been proposed, however, most of the previous models have been concerned w...

A theoretical investigation into the prediction and measurement of squeeze film stiffness and damping for double hole entry hybrid journal bearings has been undertaken together with a review of previous work to identify critical bearing parameters. The analysis used a partial differentiation of the Poiseuille and Hagen-Poiseuille flow equations to develop a mathematical model for the bearing sq...

A new compact model of squeeze-film damping is developed based on the numerical solution of the Boltzmann kinetic equation. It provides a simple expression for the damping coefficient and the quality factor valid through the slip, transitional and free-molecular regimes. In this work, we have applied statistical analysis to the current model using the chi-squared test. The damping predictions a...

In dynamic plowing lithography, the sample surface is indented using a vibrating tip in tapping mode atomic force microscopy. During writing, the gap between the cantilever and the sample surface is very small, usually on the order of micrometers. High vibration frequency and small distance induce squeeze film air damping from the air in the gap. This damping can cause variations in the cantile...

The accurate modelling of damping is essential to capture the dynamic behaviour of a MEMS device. Our interest lies in squeeze-film damping which models the behaviour of a fluid in small gaps between a fixed surface and a structure moving perpendicular to this surface (Fig.1). The lateral dimensions of the surfaces are large compared to the gap and the system is considered isothermal. Squeeze f...

Air-film damping, which dominates over other losses, plays a significant role in the dynamic response of many micro-fabricated devices with a movable mass suspended by various bearing mechanisms. Modeling the damping characteristics accurately will be greatly helpful to the bearing design, control, and test in various micromotor devices. This paper presents the simulated and experimental squeez...

In this paper, analytical and numerical methods for simulating squeeze-film air damping affecting suspended and perforated movable micro-surfaces are analyzed. Numerical solutions are obtained by full 3-D Navier-Stokes numerical analysis, carried out by a commercial finite element code, COMSOL Multiphysics, and are compared with those obtained using different analytical models proposed in liter...

Squeeze film dampers (SFDs) are often used in machines with high rotational speed to reduce non-periodic behavior by creating external damping. There are some structural parameters which are of great importance in designing these systems, such as oil film thickness and inner race mass of SFD. Moreover, there is a crucial parameter associated with manufacturing process, under the title of wavine...

We present an easy-to-use toolbox for the automated generation of reduced-order mixed-level models for the evaluation of squeeze-film damping in microelectromechanical systems. The toolbox is programmed in JAVA and heavily exploits the functionality provided by the COMSOL API. The results obtained from mixed-level model simulation performed in COMSOL Multiphysics agree very well with experiment...