科研成果 by Type: 期刊论文

2009
Liu JF, Chen YQ, Sun SL. Small polyhedron reconnection for mesh improvement and its implementation based on advancing front technique. International Journal for Numerical Methods in Engineering. 2009;79:1004-1018.Abstract
Local transformation, or topological reconnection, is one of the effective procedures for mesh improvement method, especially for three-dimensional tetrahedral mesh. The most frequently used local transformations for tetrahedral mesh are so-called elementary flips, such as 2-3 flip, 3-2 flip. 2-2 flip, and 4-4 flip. Owing to the reason that these basic transformations simply make a selection from several possible configurations within a relatively small region, the improvement of mesh quality is confined. In order to further improve the quality of mesh, the authors recently suggested a new local transformation operation, small polyhedron reconnection (SPR) operation, which seeks for the optimal tetrahedralization of a polyhedron with a certain number of nodes and faces (typically composed of 20-40 tetrahedral elements).This paper is an implementation of the suggested method. The whole process to improve the mesh quality by SPR operation is presented; in addition, some strategies, similar to those used in advancing front technique, are introduced to speed up the operation. The numerical experiment shows that SPR operation is quite effective in mesh improvement and more suitable than elementary flips when combined with smoothing approach. The operation can be applied to practical problems, gaining high mesh quality with acceptable cost for computational time. Copyright (C) 2009 John Wiley & Sons, Ltd.
2008
Liu J, Li S, Chen Y. A fast and practical method to pack spheres for mesh generation. Acta Mechanica SinicaActa Mechanica Sinica. 2008;24:439-447.Abstract
Sphere packing is an attractive way to generate high quality mesh. Several algorithms have been proposed in this topic, however these algorithms are not sufficiently fast for large scale problems. The paper presents an efficient sphere packing algorithm which is much faster and appears to be the most practical among all sphere packing methods presented so far for mesh generation. The algorithm packs spheres inside a domain using advancing front method. High efficiency has resulted from a concept of 4R measure, which localizes all the computations involved in the whole sphere packing process.
赵前程, 陈永强, 刘奕, 袁明武. 火灾作用下体育场馆结构破坏数值分析. 应用基础与工程科学学报. 2008;16:854-862.
Liu J, Li S, Chen Y. A fast and practical method to pack spheres for mesh generation. Acta Mechanica Sinica. 2008;24:439-447.
2007
Liu J, Chen B, Chen Y. Boundary recovery after 3D Delaunay tetrahedralization without adding extra nodes. International Journal for Numerical Methods in EngineeringInternational Journal for Numerical Methods in Engineering. 2007;72:744-756.Abstract
In this paper, we investigate boundary recovery, the problem that has troubled researchers ever since Delaunay-based methods were applied to generate mesh. There are a number of algorithms for boundary recovery already and most of them depend heavily on adding extra nodes. In this paper, we make an effort to seek a method to recover boundaries without using extra nodes.It was noted that some previous algorithms imposed artificial boundary constraints on a meshing problem at the recovering stage; we first try to discard these artificial constraints and thus make things easier. Then a new method is proposed by which the boundaries can be recovered by means of two operations: (1) creating a segment in the mesh and (2) removing a segment from the mesh. Both operations are special cases of a general local transformation called small polyhedron reconnection operation. The method works well when coupled with the sphere-packing method proposed by the first author. If the mesh sizing function is suitable, a good configuration of nodes will be created accordingly by the sphere-packing method and the boundary can be recovered by the local transformation presented here without inserting extra nodes. Copyright (c) 2007 John Wiley & Sons, Ltd.
Chen Y, Sun S, Liu Y. Numerical Simulation of the Mechanical Properties and Failure of Heterogeneous Elasto-Plastic Materials. Tsinghua Science & Technology. 2007;12:527-532.
Liu J, Chen B, Chen Y. Boundary recovery after 3D Delaunay tetrahedralization without adding extra nodes. International Journal for Numerical Methods in Engineering. 2007;72:744.
2004
史宝军, 袁明武, 陈永强. 无网格方法数值结果的可视化方法与实现. 工程力学. 2004;21:51-55.
2003
Chen YQ, Yao ZH, Zheng XP. Theoretical statistical solution and numerical simulation of heterogeneous brittle materials. Acta Mechanica Sinica. 2003;19:276-284.Abstract
The analytical stress-strain relation with heterogeneous parameters is derived for the heterogeneous brittle materials under a uniaxial extensional load, in which the distributions of the elastic modulus and the failure strength are assumed to be statistically independent. This theoretical solution gives an approximate estimate of the equivalent stress-strain relations for 3-D heterogeneous materials. In one-dimensional cases it may provide comparatively accurate results. The theoretical solution can help us to explain how the heterogeneity influences the mechanical behaviors. Further, a numerical approach is developed to model the non-linear behavior of three-dimensional heterogeneous brittle materials. The lattice approach and statistical techniques are applied to simulate the initial heterogeneity of heterogeneous materials. The load increment in each loading stage is adaptively determined so that the better approximation of the failure process can be realized. When the maximum tensile principal strain exceeds the failure strain, the elements are considered to be broken, which can be carried out by replacing its Young's modulus with a very small value. A 3-D heterogeneous brittle material specimen is simulated during a full failure process. The numerical results are in good agreement with the analytical solutions and experimental data.
陈永强, 林葱郁, 姚振汉, 郑小平. 非均匀材料破坏过程数值模拟的边界元法研究. 工程力学. 2003;20:19-25.
陈永强, 郑小平, 姚振汉. 非均匀材料的应变软化及叠层复合材料破坏过程的数值模拟. 计算物理. 2003;20:14-20.
2002
Chen YQ, Yao ZH, Zheng XP. 3-D numerical simulation of fracture processes in heterogeneous brittle materials. Acta Mechanica Solida Sinica. 2002;15:332-341.Abstract
By using the lattice model combined with finite element methods and statistical techniques, a numerical approach is developed to establish mechanical models of three-dimensional heterogeneous brittle materials. A special numerical code is introduced, in which a lattice model and statistical approaches are used to simulate the initial heterogeneity of material properties. The size of displacement-load step is adaptively determined so that only few elements would fail in each load step. When the tensile principal strain in an element exceeds the ultimate strain of this element, the element is considered broken and its Young's modulus is set to be very low. Some important behaviors of heterogeneous brittle materials are indicated using this code. Load-displacement curves and figures of three-dimensional fracture patterns are also numerically obtained, which are similar to those observed in laboratory tests.
陈永强, 姚振汉, 郑小平. 非均匀脆性材料本构关系统计解析解. 清华大学学报. 2002;42:1515-1518.
陈永强, 姚振汉, 郑小平. 加筋材料的格形模型和统计数值方法. 力学季刊. 2002;23:315-322.
陈永强, 郑小平, 姚振汉. 三维非均匀脆性材料破坏过程的数值模拟. 力学学报. 2002;34:351-361.
2001
陈永强, 郑小平, 姚振汉, 杜庆华. 应用格形模型和统计方法分析两相材料宏观等效力学性质. 固体力学学报. 2001;22:394-402.
2000
陈永强, 孙树勋, 王清, 姚振汉. 裂纹板贴补应力分析. 工程力学. 2000;17:49-54.

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