X.S. He¹, Q.X. Liu¹, X.C. Huang², Y.M. Chen^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.3, pp. 159-169, 2015, DOI:10.3970/cmes.2015.108.159

Abstract This paper presented dynamic response analysis for an MEMS viscometer. The responses are governed by a set of differential equations containing fractional derivatives. The memory-free Yuan-Agrawal’s approach was extended to solve fractional differential equations containing arbitrary fractional order derivative and then a simple yet efficient numerical scheme was constructed. Numerical examples show that the proposed method can provide very accurate results and computational efforts can be significantly saved. Moreover, the numerical scheme was extended to solve problems with a nonlinear spring. The influences of the nonlinear parameters on the dynamic responses were also efficiently analyzed. The dependence of the angular… More >

A. Roychowdhury^1,2, A. Nandy¹, C.S. Jog¹, R. Pratap^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.103, No.2, pp. 91-110, 2014, DOI:10.3970/cmes.2014.103.091

Abstract We present a hybrid finite element based methodology to solve the coupled fluid structure problem of squeeze film effects in vibratory MEMS devices, such as gyroscopes, RF switches, and 2D resonators. The aforementioned devices often have a thin plate like structure vibrating normally to a fixed substrate, and are generally not perfectly vacuum packed. This results in a thin air film being trapped between the vibrating plate and the fixed substrate which behaves like a squeeze film offering both stiffness and damping. For accurate modelling of such devices the squeeze film effects must be incorporated. Extensive literature is available on… More >

M. Kashtalyan^1,2, Y.A. Zhuk³

CMES-Computer Modeling in Engineering & Sciences, Vol.57, No.1, pp. 1-30, 2010, DOI:10.3970/cmes.2010.057.001

Abstract The paper investigates propagation of stationary plane longitudinal and transverse waves along the layers in adhesively bonded multilayered structures for MEMS applications in the presence of residual stresses. The multilayered structure is assumed to consist of the infinite amount of the periodically recurring layers made of two different materials possessing significantly dissimilar properties: conductive metal layer and insulating adhesive layer. It is assumed that the mechanical behaviour of both materials is nonlinear elastic and can be described with the help of the elastic Murnaghan potential depending on the three invariants of strain tensor. The problem is formulated in the framework… More >

T. Starling¹, M. F. Daqaq¹, G. Li^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.3, pp. 207-226, 2009, DOI:10.3970/cmes.2009.045.207

Abstract Input-shaping is an open-loop control technique for dynamic control of electrostatic MEMS. In MEMS applications, open-loop control is attractive as it computes a priori the required system input to achieve desired dynamic behavior without using feedback. In this work, a 3-D computational electromechanical analysis is performed to preshape the voltage commands applied to electrostatically actuate a torsional micromirror to a desired tilt angle with minimal residual oscillations. The effect of higher vibration modes on the controlled response is also investigated. It is shown that, for some structural design parameters, the first bending mode of the micromirror can have a significant… More >

P. Bettini, E. Brusa, M. Munteanu, R. Specogna, F. Trevisan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.33, No.3, pp. 215-242, 2008, DOI:10.3970/cmes.2008.033.215

Abstract Electrostatic microactuator is a paradigm of MEMS. Cantilever and double clamped microbeams are often used in microswitches, microresonators and varactors. An efficient numerical prediction of their mechanical behaviour is affected by the nonlinearity of the electromechanical coupling. Sometimes an additional nonlinearity is due to the large displacement or to the axial-flexural coupling exhibited in bending. To overcome the computational limits of the available numerical methods two new formulations are here proposed and compared. Modifying the classical beam element in the Finite Element Method to allow the implementation of a \emph {Non incremental sequential approach} is firstly proposed. The so-called \emph… More >

W.W. Liou¹, Y.C. Fang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.4, pp. 119-128, 2000, DOI:10.3970/cmes.2000.001.571

Abstract A simple implicit treatment for the low speed inflow and outflow boundary conditions for the direct simulation Monte Carlo (DSMC) of the flows in microelectromechanical systems (MEMS) is proposed. The local mean flow velocity, temperature, and number density near the subsonic boundaries were used to determine the number of molecules entering the computational domain and their corresponding velocities at every sample average step. The proposed boundary conditions were validated against micro-Poiseuille flows and micro-Couette flows. The results were compared with analytical solutions derived from the Navier-Stokes equations using first-order and second order slip-boundary conditions. The results show that the implicit… More >

Selden B. Crary¹, Peter Cousseau², David Armstrong¹, David M. Woodcock³, Eva H. Mok¹, Olivier Dubochet⁴, Philippe Lerch⁴, Philippe Renaud²

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 127-140, 2000, DOI:10.3970/cmes.2000.001.127

Abstract We present a new and unique software capability for finding statistical optimal designs of deterministic experiments on continuous cuboidal regions. The objective function for the design optimization is the minimization of the expected integrated mean squared error of prediction of the metamodel that will be found, subsequent to the running of the computer simulations, using the best linear unbiased predictor (BLUP). The assumed response-model function includes an unknown, stochastic term, Z. We prove that this criterion, which we name I_Z-optimality, is equivalent to I-optimality for non-deterministic experiments, in the limit of zero correlations among the Z's for different inputs. An… More >

B. F. Romanowicz¹, M. H. Zaman¹, S. F. Bart¹, V. L. Rabinovich¹, I. Tchertkov¹, S. Zhang¹, M. G. da Silva¹, M. Deshpande¹, K. Greiner¹, J. R. Gilbert¹, Shawn Cunningham²

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 45-64, 2000, DOI:10.3970/cmes.2000.001.045

Abstract Development of micro-electro-mechanical systems (MEMS) products is currently hampered by the need for design aids, which can assist in integration of all domains of the design. The cross-disciplinary character of microsystems requires a top-down approach to system design which, in turn, requires designers from many areas to work together in order to understand the effects of one sub-system on another. This paper describes current research on a methodology and tool-set which directly support such an integrated design process. More >

Per Ljung¹, Martin Bächtold², Mirko Spasojevic²

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 21-30, 2000, DOI:10.3970/cmes.2000.001.021

Abstract This paper presents AutoMEMS®, a numerical simulation environment to efficiently analyze the behavior of large real-world MEMS designs. By automating surface-based model generation, meshing and field solver tools, it is possible to rapidly model large complex MEMS devices. More >

Morteza Eslamian^1,2, M. Ziad Saghir^1,3

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.4, pp. 353-380, 2012, DOI:10.3970/fdmp.2012.008.353

Abstract In this paper recent advances pertinent to the applications of thermodiffusion or thermomigration in the fabrication of micro and nano metal-doped semiconductor-based patterns and devices are reviewed and discussed. In thermomigration, a spot, line, or layer of a p-type dopant, such as aluminum, which is deposited on a semiconductor surface, penetrates into the semiconductor body due to the presence of a temperature gradient applied across the wafer body. The trails of p-doped regions within an n-type semiconductor, in the form of columns or walls, may be used for several applications, such as the isolation of a part of a semiconductor… More >