Bingrui Ju¹, Wenzhen Qu^1,2,*, Yan Gu^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.3, pp. 2677-2690, 2023, DOI:10.32604/cmes.2023.025886

Abstract This paper develops a new numerical framework for mode III crack problems of thin-walled structures by integrating multiple advanced techniques in the boundary element literature. The details of special crack-tip elements for displacement and stress are derived. An exponential transformation technique is introduced to accurately calculate the nearly singular integral, which is the key task of the boundary element simulation of thin-walled structures. Three numerical experiments with different types of cracks are provided to verify the performance of the present numerical framework. Numerical results demonstrate that the present scheme is valid for mode III crack problems of thin-walled structures with… More >

Y.C. Shiah¹, C.L. Tan^2,3, Li-Ding Chan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.1, pp. 15-33, 2015, DOI:10.3970/cmes.2015.109.015

Abstract In the conventional boundary element method (BEM), the presence of singular kernels in the boundary integral equation or integral identities causes serious inaccuracy of the numerical solutions when the source and field points are very close to each other. This situation occurs commonly in elastostatic analysis of thin structures. The numerical inaccuracy issue can be resolved by some regularization process. Very recently, the self-regularization scheme originally proposed by Cruse and Richardson (1996) for 2D stress analysis has been extended and modified by He and Tan (2013) to 3D elastostatics analysis of isotropic bodies. This paper deals with the extension of… More >

Guizhong Xie¹, Jianming Zhang^1,2, Cheng Huang¹, Chenjun Lu¹, Guangyao Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.2, pp. 139-157, 2013, DOI:10.3970/cmes.2013.094.139

Abstract In this work, an improved exponential transformation is presented for nearly singular boundary element integrals in problems of thin structures. Accurate evaluation of nearly singular integrals is an important issue in the implementation of boundary element method (BEM) for thin structures. In this paper, the exponential transformation, which was firstly developed to evaluate nearly singular integrals arising in 2D BEM, is extended into 3D BEM to deal with nearly singular integrals. Firstly, a novel (α,β) coordinate system is introduced. Then, the conventional distance function is modified into a new form in (α,β) coordinate system. Based on the refined distance function,… More >

J.H. Lv¹, Y. Miao^1,2, W.H. Gong¹, H.P. Zhu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.2, pp. 113-131, 2013, DOI:10.3970/cmes.2013.093.113

Abstract Accurate numerical evaluation of the nearly singular boundary integrals is a major concerned issue in the implementation of boundary element method (BEM). In this paper, a general distance function independent on the nearly singular point is proposed. Combined with an iteration process, the position of the nearly singular point can be obtained more easily. Then, an extended form of the sinh transformation using the general distance function, which automatically takes into account the intrinsic coordinate of the nearly singular point and the minimum distance from source point to the element in the intrinsic parameter plane, is developed to deal with… More >

J.H. Lv¹, Y. Miao^1,2, H.P. Zhu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.2, pp. 101-117, 2013, DOI:10.3970/cmes.2013.091.101

Abstract The accurate and efficient evaluation of nearly singular integrals is one of the major concerned problems in the implementation of the boundary element method (BEM). Among the various commonly used nonlinear transformation methods, the distance transformation technique seems to be a promising method to deal with various orders of nearly singular integrals both in potential and elasticity problems. In this paper, some drawbacks of the conventional distance transformation, such as the sensitivity to the position of projection point, are investigated by numerical tests. A general distance transformation technique is developed to circumvent these drawbacks, which is aimed to remove or… More >

Yaoming Zhang¹, Yan Gu¹, Jeng-Tzong Chen²

CMES-Computer Modeling in Engineering & Sciences, Vol.50, No.1, pp. 1-20, 2009, DOI:10.3970/cmes.2009.050.001

Abstract There exist nearly singular integrals for thin walled structures in the boundary element method (BEM). In this paper, an efficient analytical method is developed to deal with the nearly singular integrals in the boundary integral equations (BIEs) for 2-D thin walled structures. The developed method is possible for problems defined in high-order geometry elements when the nearly singular integrals need to be calculated. For the analysis of nearly singular integrals with high-order geometry elements, much fewer boundary elements can be used to achieve higher accuracy. More importantly, computational models of thin walled structures or thin shapes in structures demand a… More >

Y.M. Zhang¹, Y. Gu¹, J.T. Chen²

CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.3, pp. 227-248, 2009, DOI:10.3970/cmes.2009.045.227

Abstract The accurate evaluation of nearly singular integrals is one of the major concerned problems in the boundary element method (BEM). Although the current methods have achieved great progress, it is often possible only for problems defined in the simplest geometrical domains when the nearly singular integrals need to be calculated. However, engineering processes occur mostly in complex geometrical domains, and always, involve nonlinearities of the unknown variables and its derivatives. Therefore, effective methods of dealing with nearly singular integrals for such practical problems are necessary and need to be further investigated. In this paper, a general strategy based on a… More >