Hamid Ghasemi¹, Harold S. Park², Xiaoying Zhuang^{3, 4, *}, Timon Rabczuk^{5, 6}

CMC-Computers, Materials & Continua, Vol.65, No.2, pp. 1157-1179, 2020, DOI:10.32604/cmc.2020.08358 - 20 August 2020

Abstract Flexoelectricity is a general electromechanical phenomenon where the electric polarization exhibits a linear dependency to the gradient of mechanical strain and vice versa. The truncated pyramid compression test is among the most common setups to estimate the flexoelectric effect. We present a three-dimensional isogeometric formulation of flexoelectricity with its MATLAB implementation for a truncated pyramid setup. Besides educational purposes, this paper presents a precise computational model to illustrate how the localization of strain gradients around pyramidal boundary shapes contributes in generation of electrical energy. The MATLAB code is supposed to help learners in the Isogeometric More >

Jinlan Xu^*, Ningning Sun, Gang Xu

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.2, pp. 627-642, 2020, DOI:10.32604/cmes.2020.010341 - 20 July 2020

Abstract This paper presents a novel approximating method to construct highprecision single-patch representation of B-spline surface from a multi-patch representation for isogeometric applications. In isogeometric analysis, multi-patch structure is not easy to achieve high continuity between neighboring patches which will reduce the advantage of isogeometric analysis in a sense. The proposed method can achieve high continuity at surface stitching region with low geometric error, and this technique exploits constructing the approximate surface with several control points are from original surfaces, which guarantees the local feature of the surface can be well-preserved with high precision. With the More >

Yang Xia^*, Luting Deng, Jian Zhao

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.2, pp. 605-626, 2020, DOI:10.32604/cmes.2020.010204 - 20 July 2020

Abstract Geometric fitting based on discrete points to establish curve structures is an important problem in numerical modeling. The purpose of this paper is to investigate the geometric fitting method for curved beam structure from points, and to get high-quality parametric model for isogeometric analysis. A Timoshenko beam element is established for an initially curved spacial beam with arbitrary curvature. The approximation and interpolation methods to get parametric models of curves from given points are examined, and three strategies of parameterization, meaning the equally spaced method, the chord length method and the centripetal method are considered.… More >

Shige Wang¹, Zhongwang Wang¹, Leilei Chen¹, Haojie Lian^2,3,*, Xuan Peng⁴, Haibo Chen⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.2, pp. 585-604, 2020, DOI:10.32604/cmes.2020.09904 - 20 July 2020

Abstract The paper applied the isogeometric boundary element method (IGABEM) to thermoelastic problems. The Non-Uniform Rational B-splines (NURBS) used to construct geometric models are employed to discretize the boundary integral formulation of the governing equation. Due to the existence of thermal stress, the domain integral term appears in the boundary integral equation. We resolve this problem by incorporating radial integration method into IGABEM which converts the domain integral to the boundary integral. In this way, IGABEM can maintain its advantages in dimensionality reduction and more importantly, seamless integration of CAD and numerical analysis based on boundary More >

Long Chen¹, Li Xu¹, Kai Wang¹, Baotong Li^2,*, Jun Hong²

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 203-225, 2020, DOI:10.32604/cmes.2020.09896 - 19 June 2020

Abstract The geometric model and the analysis model can be unified together through the isogeometric analysis method, which has potential to achieve seamless integration of CAD and CAE. Parametric design is a mainstream and successful method in CAD field. This method is not continued in simulation and optimization stage because of the model conversion in conventional optimization method based on the finite element analysis. So integration of the parametric modeling and the structural optimization by using isogeometric analysis is a natural and interesting issue. This paper proposed a method to realize a structural optimization of parametric… More >

Chao Mei, Qifu Wang^*, Chen Yu, Zhaohui Xia

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 179-202, 2020, DOI:10.32604/cmes.2020.09948 - 19 June 2020

Abstract This paper presents a topology optimization method for variable stiffness composite panels with varying fiber orientation and curvilinear fiber path. Non-uniform rational B-Splines (NURBS) based Isogeometric analysis (IGA) is utilized for the numerical computation of the general minimum compliance problem. The sensitivity analysis of the structure compliance function for the density and bi-layer orientation is conducted. The bi-layer fiber paths in the design domain are generated using streamline method and updated by divided pieces reselection method after the optimization process. Several common examples are tested to demonstrate the effectiveness of the method. The results show More >

Gang Zhao^1,2, Jiaming Yang¹, Wei Wang^1,*, Yang Zhang¹, Xiaoxiao Du¹, Mayi Guo¹

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1033-1059, 2020, DOI:10.32604/cmes.2020.09920 - 28 May 2020

Abstract In this paper, a new isogeometric topology optimization (ITO) method is proposed by using T-splines based isogeometric analysis (IGA). The arbitrarily shaped design domains, directly obtained from CAD, are represented by a single T-spline surface which overcomes the topological limitations of Non-Uniform Rational B-Spline (NURBS). The coefficients correlated with control points are directly used as design variables. Therefore, the T-spline basis functions applied for geometry description and calculation of structural response are simultaneously introduced to represent the density distribution. Several numerical examples show that the proposed approach leads to a coherent workflow to handle design More >

Mayi Guo, Gang Zhao, Wei Wang^*, Xiaoxiao Du, Ran Zhang, Jiaming Yang

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.2, pp. 821-843, 2020, DOI:10.32604/cmes.2020.09898 - 01 May 2020

Abstract Nonlinear behaviors are commonplace in many complex engineering applications, e.g., metal forming, vehicle crash test and so on. This paper focuses on the T-spline based isogeometric analysis of two-dimensional nonlinear problems including general large deformation hyperelastic problems and small deformation elastoplastic problems, to reveal the advantages of local refinement property of T-splines in describing nonlinear behavior of materials. By applying the adaptive refinement capability of T-splines during the iteration process of analysis, the numerical simulation accuracy of the nonlinear model could be increased dramatically. The Bézier extraction of the T-splines provides an element structure for More >

Bingxiao Du¹, Yong Zhao^{1, *}, Wen Yao², Xuan Wang³, Senlin Huo¹

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.3, pp. 1119-1140, 2020, DOI:10.32604/cmes.2020.08859 - 01 March 2020

Abstract A general and new explicit isogeometric topology optimisation approach with moving morphable voids (MMV) is proposed. In this approach, a novel multiresolution scheme with two distinct discretisation levels is developed to obtain high-resolution designs with a relatively low computational cost. Ersatz material model based on Greville abscissae collocation scheme is utilised to represent both the Young’s modulus of the material and the density field. Two benchmark examples are tested to illustrate the effectiveness of the proposed method. Numerical results show that high-resolution designs can be obtained with relatively low computational cost, and the optimisation can More >

Chen Yu¹, Qifu Wang^{1, ∗}, Chao Mei¹, Zhaohui Xia¹

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.3, pp. 779-803, 2020, DOI:10.32604/cmes.2020.09363 - 01 March 2020

Abstract This paper proposes a multiscale isogeometric topology optimization (ITO) method where the configuration and layout of microstructures are optimized simultaneously. At micro scale, a shape deformation method is presented to transform a prototype microstructure (PM) for obtaining a series of graded microstructures (GMs), where microstructural skeleton based on the level set framework is applied to retain more topology features and improve the connectability. For the macro scale calculation, the effective mechanical properties can be estimated by means of the numerical homogenization method. By adopting identical non-uniform rational basis splines (NURBS) as basis functions for both More >