Home / Journals / CMES / Vol.114, No.3, 2018
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  • Open Access

    ARTICLE

    Bifurcation-Based Stability Analysis of Electrostatically Actuated Micromirror as a Two Degrees of Freedom System

    Kuntao Ye1,*, Yan Luo1, Yingtao Jiang2,*
    CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 261-276, 2018, DOI:10.3970/cmes.2018.114.261
    Abstract Torsional micromirror devices have been widely used in micro displays, RF switches, optical communications, and optical coherence tomography systems. In order to study the stability of electrostatically driven torsional micromirror system with double bottom plates and two voltage sources, a dimensionless, two degrees of freedom (2-DoF) dynamic model was constructed. Governed by the dimensionless phase space model equation, the pull-in and bifurcation phenomena were analyzed using the Hamiltonian method and numerical simulation. In particular, the influence of the damping coefficient and the torsion-bending coupling effect on the phase trajectory was investigated. Furthermore, the conditions that can lead to pull-in were… More >

  • Open Access

    ARTICLE

    AdaBoosting Neural Network for Short-Term Wind Speed Forecasting Based on Seasonal Characteristics Analysis and Lag Space Estimation

    Haijian Shao1, 2, Xing Deng1, 2, *
    CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 277-293, 2018, DOI:10.3970/cmes.2018.114.277
    Abstract High accurary in wind speed forcasting remains hard to achieve due to wind’s random distribution nature and its seasonal characteristics. Randomness, intermittent and nonstationary usually cause the portion problem of the wind speed forecasting. Seasonal characteristics of wind speed means that its feature distribution is inconsistent. This typically results that the persistence of excitation for modeling can not be guaranteed, and may severely reduce the possibilities of high precise forecasting model. In this paper, we proposed two effective solutions to solve the problems caused by the randomness and seasonal characteristics of the wind speed. (1) Wavelet analysis is used to… More >

  • Open Access

    ARTICLE

    Numerical Investigation of Convective Heat Transfer and Friction in Solar Air Heater with Thin Ribs

    Sanjay K. Sharma1, V. R. Kalamkar1, *
    CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 295-319, 2018, DOI:10.3970/cmes.2018.114.295
    Abstract The three-dimensional numerical investigation of an incompressible flow through rib roughened solar air heater is carried out. A combination of thin transverse and truncated ribs is attached on the absorber plate to study its effect on the heat transfer and friction factor. The parameters in the form of Reynolds number (Re) of 4000-16000, relative roughness pitch (P/e) of 8-18 and relative roughness height (e/Dh) of 0.0366-0.055 is considered for the analysis. The CFD code ANSYS FLUENT is used to solve the governing equations of turbulent flow. The RNG k–ε turbulence model is used to solve the transport equations with enhanced… More >

  • Open Access

    ARTICLE

    Stability Analysis of Network Controlled Temperature Control System with Additive Delays

    V. Venkatachalam1, *, D. Prabhakaran1
    CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 321-334, 2018, DOI:10.3970/cmes.2018.114.321
    Abstract This paper presents, using Lyapunov-Krasovskii functional technique combined with reciprocal convex lemma is considered for a networked control temperature control system with additive time-varying-delays. In the stability analysis, a new LK functional is assumed, and take the time-derivative of the (LK) functional, using reciprocal convex combination technique was employed to obtain less conservative stability criteria. Finally, the proposed stability analysis culminates into a stability criterion in the LMI (linear matrix inequalities) framework. The results obtained are in accordance with the theoretically obtained in the temperature control system and they are closer to the standard benchmark temperature-control system. More >

  • Open Access

    ARTICLE

    A Multi-Layered Model for Heat Conduction Analysis of Thermoelectric Material Strip

    Shenghu Ding1,*, Qingnan Liu1
    CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 335-349, 2018, DOI:10.3970/cmes.2018.114.335
    Abstract A multi-layered model for heat conduction analysis of a thermoelectric material strip (TEMs) with a Griffith crack under the electric flux and energy flux load has been developed. The materials parameters of the TEMs vary continuously in an arbitrary manner. To derive the solution, the TEMs is divided into several sub-layers with different material properties. The mixed boundary problem is reduced to a system of singular integral equations, which are solved numerically. The effect of strip width on the electric flux intensity factor and thermal flux intensity factor are studied. More >

  • Open Access

    ARTICLE

    Fast Solving the Cauchy Problems of Poisson Equation in an Arbitrary Three-Dimensional Domain

    Cheinshan Liu1,2, Fajie Wang1,3,*, Wenzheng Qu4,*
    CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 351-380, 2018, DOI:10.3970/cmes.2018.114.351
    Abstract In this paper we propose a novel two-stage method to solve the three-dimensional Poisson equation in an arbitrary bounded domain enclosed by a smooth boundary. The solution is decomposed into a particular solution and a homogeneous solution. In the first stage a multiple-scale polynomial method (MSPM) is used to approximate the forcing term and then the formula of Tsai et al. [Tsai, Cheng, and Chen (2009)] is used to obtain the corresponding closed-form solution for each polynomial term. Then in the second stage we use a multiple/scale/direction Trefftz method (MSDTM) to find the solution of Laplace equation, of which the… More >

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