Home / Journals / CMES / Vol.115, No.2, 2018
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  • Open Access

    ARTICLE

    A New Interface Identification Technique Based on Absolute Density Gradient for Violent Flows

    Yan Zhou1, Qingwei Ma*
    CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.2, pp. 131-147, 2018, DOI: 10.3970/cmes.2018.00249
    Abstract An identification technique for sharp interface and penetrated isolated particles is developed for simulating two-dimensional, incompressible and immiscible two-phase flows using meshless particle methods in this paper. This technique is based on the numerically computed density gradient of fluid particles and is suitable for capturing large interface deformation and even topological changes such as merging and breaking up of phases. A number of assumed particle configurations will be examined using the technique, including these with different level of randomness of particle distribution. The tests will show that the new technique can correctly identify almost all the interface and isolated particles,… More >

  • Open Access

    ARTICLE

    Exact Solutions of the Cubic Duffing Equation by Leaf Functions under Free Vibration

    Kazunori Shinohara1
    CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.2, pp. 149-215, 2018, DOI: 10.3970/cmes.2018.02179
    Abstract Exact solutions of the cubic Duffing equation with the initial conditions are presented. These exact solutions are expressed in terms of leaf functions and trigonometric functions. The leaf function r=sleafn(t) or r=cleafn(t) satisfies the ordinary differential equation dx2/dt2=-nr2n-1. The second-order differential of the leaf function is equal to -n times the function raised to the (2n-1) power of the leaf function. By using the leaf functions, the exact solutions of the cubic Duffing equation can be derived under several conditions. These solutions are constructed using the integral functions of leaf functions sleaf2(t) and cleaf2(t) for the phase of a trigonometric… More >

  • Open Access

    ARTICLE

    Online Group Recommendation with Local Optimization

    Haitao Zou*, 1, Yifan He1, Shang Zheng1, Hualong Yu1, Chunlong Hu1
    CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.2, pp. 217-231, 2018, DOI: 10.3970/cmes.2018.00194
    Abstract There are some scenarios that need group recommendation such as watching a movie or a TV series, selecting a tourist destination, or having dinner together. Approaches in this domain can be divided into two categories: Creating group profiles and aggregating individual recommender list. Yet none of the above methods can handle the online group recommendation both efficiently and accurately and these methods either strongly limited by their application environment, or bring bias towards those users having limited connections with this group. In this work, we propose a local optimization framework, using sub-group profiles to compute the item relevance. Such method… More >

  • Open Access

    ARTICLE

    The Reduced Space Method for Calculating the Periodic Solution of Nonlinear Systems

    Haitao Liao1
    CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.2, pp. 233-262, 2018, DOI: 10.3970/cmes.2018.01004
    Abstract A hybrid method combined the reduced Sequential Quadratic Programming (SQP) method with the harmonic balance method has been developed to analyze the characteristics of mode localization and internal resonance of nonlinear bladed disks. With the aid of harmonic balance method, the nonlinear equality constraints for the constrained optimization problem are constructed. The reduced SQP method is then utilized to deal with the original constrained optimization problem. Applying the null space decomposition technique to the harmonic balance algebraic equations results in the vanishing of the nonlinear equality constraints and a simple optimization problem involving only upper and lower bound constraints on… More >

  • Open Access

    ARTICLE

    Subdivision of Uniform ωB-Spline Curves and Two Proofs of Its Ck−2-Continuity

    Jing Tang1, Mei-e Fang1,*, Guozhao Wang2
    CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.2, pp. 263-280, 2018, DOI: 10.3970/cmes.2018.01702
    Abstract ωB-splines have many optimal properties and can reproduce plentiful commonly-used analytical curves. In this paper, we further propose a non-stationary subdivision method of hierarchically and efficiently generating ωB-spline curves of arbitrary order of ωB-spline curves and prove its Ck−2-continuity by two kinds of methods. The first method directly prove that the sequence of control polygons of subdivision of order k converges to a Ck−2-continuousωB-spline curve of order k. The second one is based on the theories upon subdivision masks and asymptotic equivalence etc., which is more convenient to be further extended to the case of surface subdivision. And the problem… More >

  • Open Access

    ARTICLE

    Progressive Failure Evaluation of Composite Skin-Stiffener Joints Using Node to Surface Interactions and CZM

    A. Sane1,*, P. M. Padole1, R. V. Uddanwadiker1
    CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.2, pp. 281-294, 2018, DOI: 10.3970/cmes.2018.05046
    Abstract T shaped skin-stiffener joint are one of the most commonly used structures in aerospace components. It has been proven in various studies that these joints are susceptible to failure when loaded in pull out conditions however, in specific applications these joints undergo pull loading. De-lamination/de-bond nucleation and its growth is one of the most common failure mechanisms in a fiber reinforced composite structure. Crack growth takes place due to the induced interlaminar normal and shear stresses between different structural constituents when a load is applied. In this study, Finite Element Analysis has been performed using cohesive contact interactions on a… More >

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