Haojie Lian^1,2, Leilei Chen^2,3, Xiao Lin⁴, Wenchang Zhao^5,*, Stephane P. A. Bordas^6,7, Mingdong Zhou^8,*

CMES-Computer Modeling in Engineering & Sciences, Vol.131, No.1, pp. 1-18, 2022, DOI:10.32604/cmes.2022.019705 - 24 January 2022

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, More >

Xuan Peng^1,*, Haojie Lian^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.130, No.1, pp. 513-542, 2022, DOI:10.32604/cmes.2022.017410 - 29 November 2021

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 >

S. Morganti¹, F. Fahrendorf², L. De Lorenzis³, J. A. Evans⁴, T. J. R. Hughes^5,* and A. Reali⁶

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1125-1150, 2021, DOI:10.32604/cmes.2021.016832 - 25 November 2021

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 More >

Chao Mei^1,2, Qifu Wang^1,*, Chen Yu¹, Zhaohui Xia¹

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.2, pp. 627-659, 2021, DOI:10.32604/cmes.2021.017704 - 08 October 2021

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 More >

Jianchen Wu¹, Yujie Guo^1,*, Fangli Wang^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.128, No.3, pp. 1007-1031, 2021, DOI:10.32604/cmes.2021.016475 - 11 August 2021

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.… More >

Weihua Fang¹, Tiantang Yu^2,*, Yin Yang³

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 1315-1332, 2021, DOI:10.32604/cmes.2021.014575 - 19 February 2021

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… More >

Houlin Yang¹, Bingquan Zuo^1,2,*, Zhipeng Wei^1,2, Huixin Luo^1,2, Jianguo Fei^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 1033-1052, 2021, DOI:10.32604/cmes.2021.014493 - 19 February 2021

Abstract The isogeometric analysis method (IGA) is a new type of numerical method solving partial differential equations. Compared with the traditional finite element method, IGA based on geometric spline can keep the model consistency between geometry and analysis, and provide higher precision with less freedom. However, huge stiffness matrix from the subdivision progress still leads to the solution efficiency problems. This paper presents a multigrid method based on geometric multigrid (GMG) to solve the matrix system of IGA. This method extracts the required computational data for multigrid method from the IGA process, which also can be… More >

Leilei Chen¹, Kunpeng Li¹, Xuan Peng², Haojie Lian^3,4,*, Xiao Lin⁵, Zhuojia Fu⁶

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.1, pp. 125-146, 2021, DOI:10.32604/cmes.2021.012821 - 22 December 2020

Abstract This paper presents an isogeometric boundary element method (IGABEM) for transient heat conduction analysis. The Non-Uniform Rational B-spline (NURBS) basis functions, which are used to construct the geometry of the structures, are employed to discretize the physical unknowns in the boundary integral formulations of the governing equations. B´ezier extraction technique is employed to accelerate the evaluation of NURBS basis functions. We adopt a radial integration method to address the additional domain integrals. The numerical examples demonstrate the advantage of IGABEM in dimension reduction and the seamless connection between CAD and numerical analysis. More >

Daoyuan Yu, Shouyu Cai^*, Wenya Fan, Lan Zhang^*

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.3, pp. 787-806, 2020, DOI:10.32604/cmes.2020.09936 - 21 August 2020

Abstract In this study, a patch removing based Isogeometric analysis (PR-IGA) method is proposed to conduct the holed structural analysis with only one parametric domain, in which there are also no trimmed elements. The theoretical foundation of this novel patch removing approach is that any holed structure can be obtained by removing sub-patches (i.e., the holes) from an intact base patch. Since the parametric domains of these patches are all meshed by rectangular grids, the elements in the resulted holed structural parametric domain could all be untrimmed rectangles under certain mapping conditions. To achieve the special… More >

Yingjun Wang^1,*, Zhenpei Wang², Xiaowei Deng³, David J. Benson⁴, Damiano Pasini⁵, Shuting Wang⁶

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.3, pp. 783-785, 2020, DOI:10.32604/cmes.2020.013234 - 21 August 2020

Abstract This article has no abstract. More >