Authors: Mohammad Fathalilou Morteza Sadeghi Ghader Rezazadeh
Publish Date: 2014/05/01
Volume: 28, Issue: 4, Pages: 1141-1151
Abstract
This paper studies the size dependent behavior of materials in MEMS structures This behavior becomes noticeable for a structure when the characteristic size such as thickness or diameter is close to its internal lengthscale parameter and is insignificant for the high ratio of the characteristic size to the lengthscale parameter which is the case of the silicon base microbeams However in some types of microbeams like gold or nickel bases the size dependent effect cannot be overlooked In such cases ignoring this behavior in modeling will lead to incorrect results Some previous researchers have applied classic beam theory on their models and imposed a considerable hypothetical value of residual stress to match their theoretical results with the experimental ones The equilibrium positions or fixed points of the gold and nickel microbeams are obtained and shown that for a given DC voltage there is a considerable difference between the obtained fixed points using classic beam theory modified couple stress theory and modified strain gradient theory In addition it is shown that the calculated static and dynamic pullin voltages using higher order theories are much closer to the experimental results and are higher several times than those obtained by classic beam theoryMohammad Fathalilou received the BS degree in mechanical engineering from University of Tabriz IRAN in 2007 and the MS degree in mechanical engineering from Urmia University IRAN in 2009 He is currently working toward the PhD at University of Tabriz His current research interests include application of the nonclassic theories of elasticity as well as the nonlinear dynamics in MEMSMorteza Sadeghi received the BS degree in mechanical engineering from University of Tabriz IRAN in 1985 and the MS and Ph D degrees in mechanical engineering from University of MichiganAnn Arbor in 1989 and 1994 respectively He joined the faculty of engineering of University of Tabriz IRAN where he is a professor in the Mechanical Engineering Department His current research interests include the dynamical systems as well as modal analysis fault detection and MEMS sensorsGhader Rezazadeh received BS and MS degrees in mechanical engineering from Isfahan Technical University IRAN in 1991 and PhD in applied mechanics from Bauman Moscow State Technical University in 1997 He joined the faculty of engineering of Urmia University IRAN where he is a professor in the Mechanical Engineering Department His current research interests include the stability of structures as well as the nonlinear dynamics in MEMS
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