Home / Journals / CMES / Vol.45, No.3, 2009
Table of Content
  • Open Access

    ARTICLE

    A Computational Approach for Pre-Shaping Voltage Commands of Torsional Micromirrors

    T. Starling1, M. F. Daqaq1, G. Li1,2
    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 >

  • Open Access

    ARTICLE

    Boundary Layer Effect in BEM with High Order Geometry Elements Using Transformation

    Y.M. Zhang1, Y. Gu1, J.T. Chen2
    CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.3, pp. 227-248, 2009, DOI:10.3970/cmes.2009.045.227
    Abstract The accurate evaluation of nearly singular integrals is one of the major concerned problems in the boundary element method (BEM). Although the current methods have achieved great progress, it is often possible only for problems defined in the simplest geometrical domains when the nearly singular integrals need to be calculated. However, engineering processes occur mostly in complex geometrical domains, and always, involve nonlinearities of the unknown variables and its derivatives. Therefore, effective methods of dealing with nearly singular integrals for such practical problems are necessary and need to be further investigated. In this paper, a general strategy based on a… More >

  • Open Access

    ARTICLE

    The Particular Solutions of Chebyshev Polynomials for Reissner Plates under Arbitrary Loadings

    Chia-Cheng Tsai1
    CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.3, pp. 249-272, 2009, DOI:10.3970/cmes.2009.045.249
    Abstract Analytical particular solutions of Chebyshev polynomials are obtained for problems of Reissner plates under arbitrary loadings, which are governed by three coupled second-ordered partial differential equation (PDEs). Our solutions can be written explicitly in terms of monomials. By using these formulas, we can obtain the approximate particular solution when the arbitrary loadings have been represented by a truncated series of Chebyshev polynomials. In the derivations of particular solutions, the three coupled second-ordered PDE are first transformed into a single six-ordered PDE through the Hörmander operator decomposition technique. Then the particular solutions of this six-ordered PDE can be found in the… More >

  • Open Access

    ARTICLE

    Topological Approach for Analyzing and Modeling the Aerodynamic Hysteresis of an Airfoil

    Tao Cui1, Wenhao Liao1 and Daren Yu 1
    CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.3, pp. 273-294, 2009, DOI:10.3970/cmes.2009.045.273
    Abstract Aerodynamic hysteresis is of practical importance for the flying airfoils. Motivated by the problem of global description on the hysteresis behaviors, this paper proposes a topological approach to analyze and model the hysteresis behaviors exhibited in the airfoil flow from a viewpoint of dynamic system theory. The approach is based on the topological invariant rules of singular points under topological mapping. It is able to theoretically explain such discontinuous hysteresis phenomena, and make consistent and accurate predictions of the hysteresis behaviors in the airfoil flow. The model results have shown that the present model is in good agreement with the… More >

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