Home / Journals / CMES / Vol.92, No.3, 2013
Table of Content
  • Open Access

    ARTICLE

    An Optimal Preconditioner with an Alternate Relaxation Parameter Used to Solve Ill-Posed Linear Problems

    Chein-Shan Liu1
    CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.3, pp. 241-269, 2013, DOI:10.32604/cmes.2013.092.241
    Abstract In order to solve an ill-posed linear problem, we propose an innovative Jacobian type iterative method by presetting a conditioner before the steepest descent direction. The preconditioner is derived from an invariant manifold approach, which includes two parameters α and γ to be determined. When the weighting parameter α is optimized by minimizing a properly defined objective function, the relaxation parameter γ can be derived to accelerate the convergence speed under a switching criterion. When the switch is turned-on, by using the derived value of γ it can pull back the iterative orbit to the fast manifold. It is the… More >

  • Open Access

    ARTICLE

    Modeling Imperfect Interfaces in the Material Point Method using Multimaterial Methods

    J. A. Nairn1
    CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.3, pp. 271-299, 2013, DOI:10.32604/cmes.2013.092.271
    Abstract The “multimaterial” version of the material point method (MPM) extrapolates each material to its own velocity field on a background grid. By reconciling momenta on nodes interacting with two or more materials, MPM is able to automatically handle contact without any need for special contact elements. This paper extends multimaterial MPM to automatically handle imperfect interfaces between materials as well. The approach is to evaluate displacement discontinuity on multimaterial nodes and then add internal forces and interfacial energy determined by an imperfect interface traction law. The concept is simple, but implementation required numerous corrections to make the analysis mesh independent,… More >

  • Open Access

    ARTICLE

    Inverse Nodal Problem for the Differential Operator with a Singularity at Zero

    Emrah Yilmaz1, Hikmet Koyunbakan2, Unal Ic3
    CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.3, pp. 301-313, 2013, DOI:10.32604/cmes.2013.092.301
    Abstract In this study, some results are given about Sturm-Liouville operator having a singularity at zero. For this problem, asymptotic form of nodal data and a reconstruction formula for the potential function are given. In addition, a numerical example is established and illustrated the results in some tables and graphics. More >

  • Open Access

    ARTICLE

    Computer Modeling Chemical Vapor Infiltration of SiC Composites

    Yaochan Zhu1, Eckart Schnack1, Al Mahmudur Rahman1
    CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.3, pp. 315-326, 2013, DOI:10.32604/cmes.2013.092.315
    Abstract A novel multiphase field model is formulated to simulate the complex microstructure evolution during chemical vapor infiltration (CVI) process, which is widely used technique to produce SiC matrix composites reinforced by SiC fibers in ceramic engineer. The model consists of a set of nonlinear partial differential equations by coupling Ginzburg-Landau type phase field equations with mass/heat balance equations as well as modified Navier-Stokes equations. The microstructure evolution of preferential codeposition of Si, SiC and C under high ratio of H2 to MTS is simulated. The simulation is in good agreement with experiments result. The potential risk of blockage of the… More >

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