A numerical study of squeeze-film damping in MEMS-based structures including rarefaction effects
Journal Title: Frattura ed Integrità Strutturale - Year 2013, Vol 7, Issue 23
Abstract
In a variety of MEMS applications, the thin film of fluid responsible of squeeze-film damping results to be rarefied and, thus, not suitable to be modeled though the classical Navier-Stokes equation. The simplest way to consider fluid rarefaction is the introduction of a slight modification into its ordinary formulation, by substituting the standard fluid viscosity with an effective viscosity term. In the present paper, some squeeze-film damping problems of both parallel and torsion plates at decreasing pressure are studied by numerical solving a full 3D Navier-Stokes equation, where the effective viscosity is computed according to proper expressions already included in the literature. Furthermore, the same expressions for the effective viscosity are implemented within known analytical models, still derived from the Navier-Stokes equation. In all the considered cases, the numerical results are shown to be very promising, providing comparable or even better agreement with the experimental data than the corresponding analytical results, even at low air pressure. Thus, unlike what is usually agreed in the literature, the effective viscosity approach can be efficiently applied at low pressure regimes, especially when this is combined with a finite element analysis (FEA).
Authors and Affiliations
Maria F. Dept. of Mechanical Engineering, University of Calabria, 87036 Rende (CS), Italy. , Leonardo Pagnotta, Salvatore Nigro
Keywords
Related Articles
- EP ID EP119960
- DOI 10.3221/IGF-ESIS.23.11
- Views 80
- Downloads 0
Designing aluminium friction stir welded joints against multiaxial fatigue
The present paper investigates the accuracy of the Modified Wöhler Curve Method (MWCM) in estimating multiaxial fatigue strength of aluminium friction stir (FS) welded joints. Having developed a bespoke joini...
Fatigue crack paths and properties in A356-T6 aluminum alloy microstructurally modified by friction stir processing under different conditions
A356-T6 cast aluminum alloy is a light weight structural material, but fatigue crack initiates and propagates from a casting defect leading to final fracture. Thus it is important to eliminate casting defects. In&...
Ductile cast irons: microstructure influence on fatigue crack propagation resistance
Microstructure influence on fatigue crack propagation resistance in five different ductile cast irons (DCI) was investigated. Four ferrite/pearlite volume fractions were considered, performing fatigue crack propagation t...
Understanding the edge crack phenomenon in ceramic laminates
Layered ceramic materials (also referred to as “ceramic laminates”) are becoming one of the most promising areas of materials technology aiming to improve the brittle behavior of bulk ceramics. The utilization&nbs...
Structural transitions in a NiTi alloy: a multistage loading-unload cycle
NiTi shape memory alloys (SMAs) are increasingly used in many engineering and medical applications, because they combine special functional properties, such as shape memory effect and pseudo-elasticity, with good mechani...