Home / Journals / CMES / Vol.18, No.3, 2007
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  • Open Access

    ARTICLE

    A Geometric Deformation Constrained Level Set Method for Structural Shape and Topology Optimization

    S.Y. Wang1,2, K.M. Lim2,3, B.C. Khoo2,3, M.Y. Wang4
    CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.3, pp. 155-182, 2007, DOI:10.3970/cmes.2007.018.155
    Abstract In this paper, a geometric deformation constrained level set method is presented as an effective approach for structural shape and topology optimization. A level set method is used to capture the motion of the free boundary of a structure. Furthermore, the geometric deformation of the free boundary is constrained to preserve the structural connectivity and/or topology during the level set evolution. An image-processing-based structural connectivity and topology preserving approach is proposed. A connected components labeling technique based on the 4-neighborhood connectivity measure and a binary image is used for the present region identification. The corresponding binary image after an exploratory… More >

  • Open Access

    ARTICLE

    Weight Optimization of Skeletal Structures with Multi-Point Simulated Annealing

    L. Lamberti1,2, C. Pappalettere1,3
    CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.3, pp. 183-222, 2007, DOI:10.3970/cmes.2007.018.183
    Abstract This paper presents a novel optimization algorithm for minimizing weight of skeletal structures. The algorithm--denoted as MPISA (Multi Point Improved Simulated Annealing)--utilizes a multi-level simulated annealing scheme where different candidate designs are compared simultaneously. This is done in purpose to increase computational efficiency and to minimize the number of exact structural analyses.
    MPISA is tested in three complicated design problems of skeletal structures: (i) sizing optimization of a planar bar truss under five independent loading conditions including 200 design variables; (ii) sizing-configuration optimization of a cantilevered bar truss including 81 design variables; (iii) sizing-configuration optimization of a frame structure… More >

  • Open Access

    ARTICLE

    Numerical Generation of Freak Waves Using MLPG_R and QALE-FEM Methods

    Q.W. Ma1
    CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.3, pp. 223-234, 2007, DOI:10.3970/cmes.2007.018.223
    Abstract Two methods have been recently developed by the author and his group: one called MLPG_R (Meshless Local Petrov-Galerkin method based on Rankine source solution) and the other called QALE-FEM (Quasi Arbitrary Lagrangian-Eulerian Finite Element Method). The former is a meshless method developed from a general MLPG (Meshless Local Petrov-Galerkin) method and is more computationally efficient than the general one when applied to modelling nonlinear water waves. The later is a mesh-based method similar to a conventional finite element method (FEM) when discretizing the governing equations but different from the conventional one in managing the mesh. In this paper, they are… More >

  • Open Access

    ARTICLE

    Analysis of Shell Deformation Responses by the Meshless Local Petrov-Galerkin (MLPG) Approach

    T. Jarak1, J. Sorić1, J. Hoster1
    CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.3, pp. 235-246, 2007, DOI:10.3970/cmes.2007.018.235
    Abstract A meshless computational method based on the local Petrov-Galerkin approach for the analysis of shell structures is presented. A concept of a three dimensional solid, allowing the use of completely 3-D constitutive models, is applied. Discretization is carried out by using both a moving least square approximation and polynomial functions. The exact shell geometry can be described. Thickness locking is eliminated by using a hierarchical quadratic approximation over the thickness. The shear locking phenomena in case of thin structures and the sensitivity to rigid body motions are minimized by applying interpolation functions of sufficiently high order. The numerical efficiency of… More >

  • Open Access

    ARTICLE

    The Effect of Internal Support Conditions to the Elastoplastic Transient Response of Reissner-Mindlin Plates

    C. P. Providakis1
    CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.3, pp. 247-258, 2007, DOI:10.3970/cmes.2007.018.247
    Abstract The method of Domain/Boundary Element is used to achieve a dynamic analysis of elastoplastic thick plates resting on internal supports. All possible boundary conditions on the edge of the plate with any interior support conditions such as isolated points (column), lines (walls) or regions (patches) can be treated without practical difficulties. The formulation presented includes the effects of shear deformation and rotatory inertia following Reissner-Mindlin's deformation theory assumptions. The method employs the elastostatic fundamental solution of the problem resulting in both boundary and domain integrals due to inertia, plasticity and interior support effect terms. By discretizing the integral equations and… More >

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