Home / Journals / CMES / Vol.3, No.6, 2002
Table of Content
  • Open Access

    ARTICLE

    An Explicit Discontinuous Time Integration Method For Dynamic-Contact/Impact Problems

    Jin Yeon Cho1, Seung Jo Kim2
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 687-698, 2002, DOI:10.3970/cmes.2002.003.687
    Abstract In this work, an explicit solution procedure for the recently developed discontinuous time integration method is proposed in order to reduce the computational cost while maintaining the desirable numerical characteristics of the discontinuous time integration method. In the present explicit solution procedure, a two-stage correction algorithm is devised to obtain the solution at the next time step without any matrix factorization. To observe the numerical characteristics of the proposed explicit solution procedure, stability and convergence analyses are performed. From the stability analysis, it is observed that the proposed algorithm gives a larger critical time step than the central difference method.… More >

  • Open Access

    ARTICLE

    SGBEM (for Cracked Local Subdomain) -- FEM (for uncracked global Structure) Alternating Method for Analyzing 3D Surface Cracks and Their Fatigue-Growth

    Z. D. Han1, S. N. Atluri1
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 699-716, 2002, DOI:10.3970/cmes.2002.003.699
    Abstract As shown in an earlier work, the FEM-BEM alternating method is an efficient and accurate method for fracture analysis. In the present paper, a further improvement is formulated and implemented for the analyses of three-dimensional arbitrary surface cracks by modeling the cracks in a local finite-sized subdomain using the symmetric Galerkin boundary element method (SGBEM). The finite element method is used to model the uncracked global (built-up) structure for obtaining the stresses in an otherwise uncracked body. The solution for the cracked structural component is obtained in an iteration procedure, which alternates between FEM solution for the uncracked body, and… More >

  • Open Access

    ARTICLE

    Analysis of Elastodynamic Deformations near a Crack/Notch Tip by the Meshless Local Petrov-Galerkin (MLPG) Method

    R. C. Batra1, H.-K. Ching1
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 717-730, 2002, DOI:10.3970/cmes.2002.003.717
    Abstract The Meshless Local Petrov-Galerkin (MLPG) method is used to analyze transient deformations near either a crack or a notch tip in a linear elastic plate. The local weak formulation of equations governing elastodynamic deformations is derived. It results in a system of coupled ordinary differential equations which are integrated with respect to time by a Newmark family of methods. Essential boundary conditions are imposed by the penalty method. The accuracy of the MLPG solution is established by comparing computed results for one-dimensional wave propagation in a rod with the analytical solution of the problem. Results are then computed for the… More >

  • Open Access

    ARTICLE

    A Two-dimensional Finite Element Implementation of a Special Form of Gradient Elasticity

    L. Teneketzis Tenek1, E.C. Aifantis1,2,3
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 731-741, 2002, DOI:10.3970/cmes.2002.003.731
    Abstract A two-dimensional finite element implementation of a special form of gradient elasticity is developed and a connection between classical and the proposed gradient elasticity theory is established. A higher-order constitutive equation is adopted which involves a gradient term of a special form; the higher-order term is precisely the second gradient of the lower-order term. A weak form of the equilibrium equations, based on the principle of virtual work, is formulated for the classical problem. The problem in hand, is solved by means of the finite element method in two steps. First, the displacement field of classical elasticity is computed. Then,… More >

  • Open Access

    ARTICLE

    Computational Simulations of Micro-Indentation Tests Using Gradient Plasticity

    Jian Chen1, Huang Yuan2, Folker H. Wittmann3
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 743-754, 2002, DOI:10.3970/cmes.2002.003.743
    Abstract Experimental observation confirms that micro-hardness of metallic materials depends significantly on the indentation depth. In the present paper we discuss simulations of micro-indentation tests based on the gradient plasticity model using the finite element method. The role of intrinsic material length parameters in the gradient plasticity model is investigated. The computational results confirm that the gradient plasticity model is suitable to simulate micro-indentation tests and predicts the depth-dependent hardness in micro- and nano-indentations. Variations of micro-hardness is correlated with the intrinsic material length parameters. More >

  • Open Access

    ARTICLE

    Probabilistic and Possibilistic Analyses of the Strength of a Bonded Joint

    W. Jefferson Stroud1, T. Krishnamurthy1, Steven A. Smith2
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 755-772, 2002, DOI:10.3970/cmes.2002.003.755
    Abstract The effects of uncertainties on the predicted strength of a single lap shear joint are examined. Probabilistic and possibilistic methods are used to account for uncertainties. A total of ten variables are assumed to be random, with normal distributions. Both Monte Carlo Simulation and the First Order Reliability Method are used to determine the probability of failure. Triangular membership functions with upper and lower bounds located at plus or minus three standard deviations are used to model uncertainty in the possibilistic analysis. The alpha cut (or vertex) method is used to evaluate the possibility of failure. Linear and geometrically nonlinear… More >

  • Open Access

    ARTICLE

    Computational Aeroelasticity Using a Pressure-based Solver

    Ramji Kamakoti1, Yongsheng Lian1, Sean Regisford1, Andrew Kurdila1, Wei Shyy1
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 773-790, 2002, DOI:10.3970/cmes.2002.003.773
    Abstract The non-linear fluid-structure interaction problem is studied for two different wing configurations based on moving grid techniques. These configurations demonstrate the interaction between a rigid structure and fluid, as well as the interaction between a flexible structure and fluid. A closely-coupled approach is used to perform the combined fluid and structure interaction computations. The flow solver is an unsteady, implicit, three-dimensional, multi-block, pressure-based Navier-Stokes solver. The structure solver for the AGARD wing model is based on a linear, time-invariant model derived via classical structural finite elements whereas the flexible structural solver is based on a non-linear dynamic membrane model with… More >

  • Open Access

    ARTICLE

    Dynamic Response of 3-D Damaged Solids and Structures by BEM

    G.D. Hatzigeorgiou1, D.E. Beskos1
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 791-802, 2002, DOI:10.3970/cmes.2002.003.791
    Abstract This paper presents a general boundary element methodology for the dynamic analysis of three-dimensional inelastic solids and structures. Inelasticity is simulated with the aid of the continuum damage theory. The elastostatic fundamental solution is employed in the integral formulation of the problem and this creates in addition to the surface integrals, volume integrals due to inertia and inelasticity. Thus an interior discretization in addition to the usual surface discretization is necessary. Isoparametric linear quadrilateral elements are used for the surface discretization and isoparametric linear hexahedra for the interior discretization. Advanced numerical integration techniques for singular and nearly singular integrals are… More >

  • Open Access

    ARTICLE

    Elastic wave propagation in fiber reinforced composite materials with non-uniform distribution of fibers

    J.T. Verbis1, S.V. Tsinopoulos2, D. Polyzos2
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 803-814, 2002, DOI:10.3970/cmes.2002.003.803
    Abstract In the present work the iterative effective medium approximation (IEMA) is appropriately used for wave dispersion and attenuation predictions in fiber-reinforced composites that microscopically exhibit a non-uniform fiber distribution. Two types of composites with such irregular topology of fibers are considered. The first contains a regular distribution of clusters of fibers embedded in a composite matrix with uniformly distributed fibers, and the second a uniform distribution of matrix-rich inclusions embedded in a fiber-rich regular composite medium. The resulting from the application of the IEMA scattering problems are solved numerically by means of a two dimensional boundary element method. The obtained… More >

  • Open Access

    ARTICLE

    FE/BE Analysis of Structural Dynamics and Sound Radiation from Rolling Wheels

    L. Gaul, M. Fischer1, U. Nackenhorst2
    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 815-824, 2002, DOI:10.3970/cmes.2002.003.815
    Abstract A sequential FEM--BEM approach is employed to calculate the dynamic behavior and sound radiation of rotating wheels. The equations of motion for the wheel are developed in the frame of an Arbitrary Eulerian Lagrangian description with a time-independent formulation for steady state rolling and a spatial description of vibrations. The noise radiation caused by the vibration modes is computed by the symmetric hybrid boundary element method. More >

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