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  • Open Access


    Multi-Patch Black-White Topology Optimization in Isogeometric Analysis

    Qingyuan Hu1,*, Yuan Liang2, Menghao Liu1, Manfeng Hu1, Yawen Mao1

    CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.1, pp. 459-481, 2023, DOI:10.32604/cmes.2022.020327

    Abstract Topological optimization plays a guiding role in the conceptual design process. This paper conducts research on structural topology optimization algorithm within the framework of isogeometric analysis. For multi-component structures, the Nitsche’s method is used to glue different meshes to perform isogeometric multi-patch analysis. The discrete variable topology optimization algorithm based on integer programming is adopted in order to obtain clear boundaries for topology optimization. The sensitivity filtering method based on the Helmholtz equation is employed for averaging of curved elements' sensitivities. In addition, a simple averaging method along coupling interfaces is proposed in order to ensure the material distribution across… More >

  • Open Access


    A Parallel Computing Schema Based on IGA

    Jinggang Deng1,2, Bingquan Zuo1,2,*, Huixin Luo1,2, Weikang Xie1,2, Jiashu Yang1,2

    CMES-Computer Modeling in Engineering & Sciences, Vol.132, No.3, pp. 965-990, 2022, DOI:10.32604/cmes.2022.020631

    Abstract In this paper, a new computation scheme based on parallelization is proposed for Isogeometric analysis. The parallel computing is introduced to the whole progress of Isogeometric analysis. Firstly, with the help of the “tensorproduct” and “iso-parametric” feature, all the Gaussian integral points in particular element can be mapped to a global matrix using a transformation matrix that varies from element. Then the derivatives of Gauss integral points are computed in parallel, the results of which can be stored in a global matrix. And a middle layer is constructed to assemble the final stiffness matrices in parallel. The numerical example results… More >

  • Open Access


    Isogeometric Boundary Element Method for Two-Dimensional Steady-State Non-Homogeneous Heat Conduction Problem

    Yongsong Li1, Xiaomeng Yin2, Yanming Xu1,*

    CMES-Computer Modeling in Engineering & Sciences, Vol.132, No.2, pp. 471-488, 2022, DOI:10.32604/cmes.2022.020201

    Abstract The isogeometric boundary element technique (IGABEM) is presented in this study for steady-state inhomogeneous heat conduction analysis. The physical unknowns in the boundary integral formulations of the governing equations are discretized using non-uniform rational B-spline (NURBS) basis functions, which are utilized to build the geometry of the structures. To speed up the assessment of NURBS basis functions, the B´ezier extraction approach is used. To solve the extra domain integrals, we use a radial integration approach. The numerical examples show the potential of IGABEM for dimension reduction and smooth integration of CAD and numerical analysis. More >

  • Open Access


    Isogeometric Analysis with Local Adaptivity for Vibration of Kirchhoff Plate

    Peng Yu, Weijing Yun, Junlei Tang, Sheng He*

    CMES-Computer Modeling in Engineering & Sciences, Vol.131, No.2, pp. 949-978, 2022, DOI:10.32604/cmes.2022.018596

    Abstract Based on our proposed adaptivity strategy for the vibration of Reissner–Mindlin plate, we develop it to apply for the vibration of Kirchhoff plate. The adaptive algorithm is based on the Geometry-Independent Field approximaTion (GIFT), generalized from Iso-Geometric Analysis (IGA), and it can characterize the geometry of the structure with NURBS (Non-Uniform Rational B-Splines), and independently apply PHT-splines (Polynomial splines over Hierarchical T-meshes) to achieve local refinement in the solution field. The MAC (Modal Assurance Criterion) is improved to locate unique, as well as multiple, modal correspondence between different meshes, in order to deal with error estimation. Local adaptivity is carried… More >

  • Open Access


    Noise Pollution Reduction through a Novel Optimization Procedure in Passive Control Methods

    Haojie Lian1,2, Leilei Chen2,3, Xiao Lin4, Wenchang Zhao5,*, Stephane P. A. Bordas6,7, Mingdong Zhou8,*

    CMES-Computer Modeling in Engineering & Sciences, Vol.131, No.1, pp. 1-18, 2022, DOI:10.32604/cmes.2022.019705

    Abstract This paper proposes a novel optimization framework in passive control techniques to reduce noise pollution. The geometries of the structures are represented by Catmull-Clark subdivision surfaces, which are able to build gap-free Computer-Aided Design models and meanwhile tackle the extraordinary points that are commonly encountered in geometric modelling. The acoustic fields are simulated using the isogeometric boundary element method, and a density-based topology optimization is conducted to optimize distribution of sound-absorbing materials adhered to structural surfaces. The approach enables one to perform acoustic optimization from Computer-Aided Design models directly without needing meshing and volume parameterization, thereby avoiding the geometric errors… More >

  • Open Access


    Numerical Aspects of Isogeometric Boundary Element Methods: (Nearly) Singular Quadrature, Trimmed NURBS and Surface Crack Modeling

    Xuan Peng1,*, Haojie Lian2,*

    CMES-Computer Modeling in Engineering & Sciences, Vol.130, No.1, pp. 513-542, 2022, DOI:10.32604/cmes.2022.017410

    Abstract This work presents some numerical aspects of isogeometric boundary element methods (IGABEM). The behavior of hyper-singular and nearly-singular integration is first explored on the distorted NURBS surface. Several numerical treatments are proposed to enhance the quadrature in the framework of isogeometric analysis. Then a numerical implementation of IGABEM on the trimmed NURBS is detailed. Based on this idea, the surface crack problem is modeled incorporation with the phantom element method. The proposed method allows the crack to intersect with the boundary of the body while preserving the original parametrization of the NURBS-based CAD geometry. More >

  • Open Access


    Isogeometric Collocation: A Mixed Displacement-Pressure Method for Nearly Incompressible Elasticity

    S. Morganti1, F. Fahrendorf2, L. De Lorenzis3, J. A. Evans4, T. J. R. Hughes5,* and A. Reali6

    CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1125-1150, 2021, DOI:10.32604/cmes.2021.016832

    Abstract We investigate primal and mixed u−p isogeometric collocation methods for application to nearly-incompressible isotropic elasticity. The primal method employs Navier’s equations in terms of the displacement unknowns, and the mixed method employs both displacement and pressure unknowns. As benchmarks for what might be considered acceptable accuracy, we employ constant-pressure Abaqus finite elements that are widely used in engineering applications. As a basis of comparisons, we present results for compressible elasticity. All the methods were completely satisfactory for the compressible case. However, results for low-degree primal methods exhibited displacement locking and in general deteriorated in the nearly-incompressible case. The results for… More >

  • Open Access


    An XBi-CFAO Method for the Optimization of Multi-Layered Variable Stiffness Composites Using Isogeometric Analysis

    Chao Mei1,2, Qifu Wang1,*, Chen Yu1, Zhaohui Xia1

    CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.2, pp. 627-659, 2021, DOI:10.32604/cmes.2021.017704

    Abstract This paper presents an effective fiber angle optimization method for two and multi-layered variable stiffness composites. A gradient-based fiber angle optimization method is developed based on isogeometric analysis (IGA). Firstly, the element densities and fiber angles for two and multi-layered composites are synchronously optimized using an extended Bi-layered continuous fiber angle optimization method (XBi-CFAO). The densities and fiber angles in the base layer are attached to the control points. The structure response and sensitivity analysis are accomplished using the non-uniform rational B-spline (NURBS) based IGA. By the benefit of the B-spline space, this method is free from checkerboards, and no… More >

  • Open Access


    Thermally Induced Vibration Analysis of Flexible Beams Based on Isogeometric Analysis

    Jianchen Wu1, Yujie Guo1,*, Fangli Wang1,2

    CMES-Computer Modeling in Engineering & Sciences, Vol.128, No.3, pp. 1007-1031, 2021, DOI:10.32604/cmes.2021.016475

    Abstract Spacecraft flexible appendages may experience thermally induced vibrations (TIV) under sudden heating loads, which in consequence will be unable to complete their intended missions. Isogeometric analysis (IGA) utilizes, in an isoparametric concept, the same high order and high continuity non-uniform rational B-splines (NURBS) to represent both the geometry and the physical field of the structure. Compared to the traditional Lagrange polynomial based finite element method where only C0-continuity across elements can be achieved, IGA is geometrically exact and naturally fulfills the C1-continuity requirement of Euler–Bernoulli (EB) beam elements, therefore, does not need extra rotational degrees-of-freedom. In this paper, we present… More >

  • Open Access


    Adaptive Extended Isogeometric Analysis for Steady-State Heat Transfer in Heterogeneous Media

    Weihua Fang1, Tiantang Yu2,*, Yin Yang3

    CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 1315-1332, 2021, DOI:10.32604/cmes.2021.014575

    Abstract Steady-state heat transfer problems in heterogeneous solid are simulated by developing an adaptive extended isogeometric analysis (XIGA) method based on locally refined non-uniforms rational B-splines (LR NURBS). In the XIGA, the LR NURBS, which have a simple local refinement algorithm and good description ability for complex geometries, are employed to represent the geometry and discretize the field variables; and some special enrichment functions are introduced into the approximation of temperature field, thus the computational mesh is independent of the material interfaces, which are described with the level set method. Similar to the approximation of temperature field, a temperature gradient recovery… More >

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