Home / Journals / CMES / Vol.3, No.4, 2002
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  • Open Access

    EDITORIAL

    Virtual Tribology: Integrating Model-Based Simulations with Modern Computation/Information Technologies

    Q. Jane Wang1, Michael D. Bryant2, Leon M. Keer1, Richard F. Salant3
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 417-430, 2002, DOI:10.3970/cmes.2002.003.417
    Abstract This article has no abstract. More >

  • Open Access

    ARTICLE

    Combining Lumped Parameter Bond Graphs with Finite Element Shafts in a Gearbox Model

    J. Choi1, M.D. Bryant2
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 431-446, 2002, DOI:10.3970/cmes.2002.003.431
    Abstract This paper presents an updated bond graph model of a gearbox, which now includes bending of shafts. The gearbox system has an input shaft, layshaft, output shaft, spur gears, bearings, and housing. The bond graph model integrates separate sub-models into a composite model. Sub-modules include tooth-to-tooth contact, rotor dynamics of shafts, global dynamics of the gearbox housing structure, and shaft bending modeled by finite element modeling. The tooth-to-tooth model includes tooth bending; shaft torsion; gear inertia; conversion of gear torque into tooth forces; tooth contact mechanics; and multiple tooth contact. To analyze shaft dynamics more precisely, elementary finite element theory… More >

  • Open Access

    ARTICLE

    Simulations of Scuffing Based on a Dynamic System Model

    Yuanzhong Hu1, Yuchuan Liu, Hui Wang
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 447-454, 2002, DOI:10.3970/cmes.2002.003.447
    Abstract Scuffing, a major cause of failure in automobile engines, is considered as a dynamic process in this study. Local adhesions may occur randomly in lubricated contacts due to the existence of asperity contact and breakdown of lubricating films. Scuffing would take place if the local events develop rapidly into a large-scale plastic deformation and catastrophic failure. A system dynamic model established in the present paper allows one to predict dynamic behavior of a tribological system through numerical solutions of a group of differential equations. Results show that a transition to adhesion begins when the surface temperature goes beyond a critical… More >

  • Open Access

    ARTICLE

    Thermohydrodynamic Analysis of Journal Bearings Lubricated with Multigrade Oils

    J.Y. Jang1, M.M. Khonsari2
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 455-464, 2002, DOI:10.3970/cmes.2002.003.455
    Abstract Thermohydrodynamic analysis of journal bearings lubricated with multigrade oils is presented. Design charts are presented that enable one to readily estimate the bearing maximum temperature and the shaft temperature using a series of dimensionless parameters introduced in this paper. More >

  • Open Access

    ARTICLE

    Temperature Distributions and Thermoelastic Displacements In Moving Bodies

    Shuangbiao Liu, Michael J. Rodgers, Qian Wang, Leon M. Keer, Herbert S. Cheng1
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 465-482, 2002, DOI:10.3970/cmes.2002.003.465
    Abstract Computing the temperature rise and thermoelastic displacement of a material subjected to frictional heating is essential for the realistic modeling of the performance of mechanical components. This paper presents a novel set of frequency-domain expressions for the surface temperature rise and the surface normal thermoelastic displacement of a moving three-dimensional elastic halfspace subjected to arbitrary transient frictional heating, where the velocity of the body and its direction can be an arbitrary function of time. Frequency response functions are derived by using the Carslaw-Jaeger theory, the Seo-Mura result, and the Fourier transform. General formulas are expressed in the form of time… More >

  • Open Access

    ARTICLE

    Steady-State Temperature Rise in Coated Halfspaces and Halfplanes

    Michael J. Rodgers1, Leon M. Keer, Herbert S. Cheng
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 483-496, 2002, DOI:10.3970/cmes.2002.003.483
    Abstract The steady-state temperature rise due to frictional heating on the surface of coated halfspaces and halfplanes is described by closed form expressions in the Fourier transformed frequency domain. These frequency response functions (FRFs) include the effects of the coating and the speed of the moving heat source and apply for all Peclet number regimes. Analytical inversion of these expressions for several special cases shows the Green's functions as infinite series of images, which may be costly and slowly convergent. Also, the influence coefficients integrated from these Green's functions are not available in closed form. Applying fast Fourier transform (FFT) methods… More >

  • Open Access

    ARTICLE

    A Numerical Model for Elastoplastic Rough Contact

    P. Sainsot1, C. Jacq2, D. Nélias1
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 497-506, 2002, DOI:10.3970/cmes.2002.003.497
    Abstract Pressure distributions calculated in the simulation of rough contacts show high values and induce high stresses just beneath the surface. These stresses often exceed the yield strength of the material, therefore, a purely elastic contact model is restrictive. Plastic flow occurs and modifies the surface shape and consequently modifies the surface pressure.
    This paper presents a numerical model for 3D-elastoplastic rough contact. It allows the determination of real pressure and permanent surface displacement (flattening of asperities) as well as residual stresses and plastic strains useful in fatigue analysis. The material is assumed to follow the Von-Mises yield criterion with… More >

  • Open Access

    ARTICLE

    An Implicit Finite Element Cavitation Algorithm

    Fanghui Shi, Rohit Paranjpe1
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 507-516, 2002, DOI:10.3970/cmes.2002.003.507
    Abstract This paper describes an implicit finite element cavitation algorithm. The cavitation problem is formulated using the complementarity form. By using the complementarity formulation, the fluid pressure in the non-cavitation region and the density of the air/fluid mixture in the cavitation region are solved simultaneously. The stream-wise biasing approach is used to produce oscillation-free solution at the fluid film reformation boundary. Implicit scheme is implemented to yield stability for time marching. The algorithm is compared with the established finite volume methods, and the robustness and the correctness of the algorithm is verified. More >

  • Open Access

    ARTICLE

    Mixed Lubrication of Coupled Journal-Thrust Bearing Systems

    Yansong Wang1, Q. Jane Wang1, Chih Lin2
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 517-530, 2002, DOI:10.3970/cmes.2002.003.517
    Abstract Many mechanisms, such as computer hard drives, gear trains, and machine tool spindle systems, operate under both axial and radial loads, which should be respectively supported by a thrust and a journal bearing. By utilizing the end face of the shaft of a journal bearing as a thrust bearing, a coupled journal-thrust bearing system can be formed. This paper presents a mixed lubrication model developed to investigate the lubrication of this coupled bearing system. A conformal-mapping method is used in the model formulation to facilitate a universal flow description. The performance of typical coupled bearing systems is numerically investigated. More >

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