Home / Journals / CMES / Vol.85, No.5, 2012
Table of Content
  • Open Access

    ARTICLE

    Modeling of Random Bimodal Structures of Composites (Application to Solid Propellants): I. Simulation of Random Packs

    V.A. Buryachenko1,2, T.L. Jackson2,3, G. Amadio3
    CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.5, pp. 379-416, 2012, DOI:10.3970/cmes.2012.085.379
    Abstract We consider a composite medium, which consists of a homogeneous matrix containing a statistically homogeneous set of multimodal spherical inclusions. This model is used to represent the morphology of heterogeneous solid propellants (HSP) that are widely used in the rocket industry. The Lubachevsky-Stillinger algorithm is used to generate morphological models of HSP with large polydisperse packs of spherical inclusions. We modify the algorithm by proposing a random shaking procedure that leads to the stabilization of a statistical distribution of the simulated structure that is homogeneous, highly mixed, and protocol independent (in sense that the statistical parameters estimated do not depend… More >

  • Open Access

    ARTICLE

    Modeling of Random Bimodal Structures of Composites (Application to Solid Propellants): II. Estimation of Effective Elastic Moduli

    V.A. Buryachenko1,2
    CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.5, pp. 417-446, 2012, DOI:10.3970/cmes.2012.085.417
    Abstract We consider a linearly elastic composite medium, which consists of a homogeneous matrix containing a statistically homogeneous set of multimodal spherical inclusions modeling the morphology of heterogeneous solid propellants (HSP). Estimates of effective elastic moduli are performed using the multiparticle effective field method (MEFM) directly taking into account the interaction of different inclusions. Because of this, the effective elastic moduli of the HSP evaluated by the MEFM are sensitive to both the relative size of the inclusions (i.e., their multimodal nature) and the radial distribution functions (RDFs) estimated from experimental data, as well as from the ensembles generated by the… More >

  • Open Access

    ARTICLE

    Homotopy Analysis of Natural Convection Flows with Effects of Thermal and Mass Diffusion

    Wei-Chung Tien1, Yue-Tzu Yang1, Cha’o-Kuang Chen1,2
    CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.5, pp. 447-462, 2012, DOI:10.3970/cmes.2012.085.447
    Abstract Both buoyancy effects of thermal and mass diffusion in the natural convection flow about a vertical plate are considered in this paper. The non-linear coupled differential governing equations for velocity, temperature and concentration fields are solved by using the homotopy analysis method. Without the need of iteration, the obtained solution is in the form of an infinite power series which indicates those series have high accuracy when comparing it with other-generated by the traditional method. The impact of the Prandtl number, Schmidt number and the buoyancy parameter on the flow are widely discussed in detail. More >

  • Open Access

    ARTICLE

    Multiple Time Scale Algorithm for Multiscale Material Modeling

    Jiaoyan Li1, Xianqiao Wang2, James D. Lee1
    CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.5, pp. 463-480, 2012, DOI:10.3970/cmes.2012.085.463
    Abstract This paper presents a novel multiple time scale algorithm integrated with the concurrent atomic/atom-based continuum modeling, which involves molecular dynamic (MD) simulation and coarse-grained molecular dynamic (CG-MD) simulation. To capture the key features of the solution region while still considering the computational efficiency, we decompose it into two sub-regions in space and utilize the central difference method with different time steps for different sub-regions to march on in time. Usually, the solution region contains a critical field and a non-critical far field. For the critical field (named atomic region) modeled by MD simulation, a relatively small time step is used… More >

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