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arXiv 1312.7016math.OCcs.NAmath.NA
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使用多面体进行拓扑优化

Topology Optimization Using Polytopes

University of Illinois at Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校);Pontifical Catholic University of Rio de Janeiro (PUC-Rio)(里约热内卢天主教大学)

Arun L. Gain, Glaucio H. Paulino, Leonardo Duarte, Ivan F. M. Menezes

AI总结:

本文提出利用多面体进行拓扑优化,通过虚拟元方法解决三维弹性问题,避免了传统有限元方法中形状函数计算的难题,提高了计算效率和精度。

摘要:

对复杂工程域进行网格化是一个具有挑战性的任务。任意多面体网格可以提供在自动离散化中所需的灵活性。多面体网格的几何特性,如无序性和元素之间的面连接性,使其特别适合拓扑优化应用。设计中的数值异常,如单节点连接和棋盘图案,这些难以制造的物理问题,通过多面体自然得到缓解。特殊的插值函数,如Wachspress、均值值坐标、最大熵形状函数,可用于处理任意形状的元素。但基于这些形状函数的有限元方法面临一些挑战,如形状函数及其导数的准确高效计算,以用于弱形式积分的数值评估。在当前工作中,我们使用虚拟元方法(VEM)解决三维弹性状态方程。VEM与标准有限元方法(FEM)的主要区别在于,在VEM中,标准基函数不是显式构造的。相反,刚度矩阵是通过投影映射直接计算的,该映射提取变形的线性成分。这种构造保证了满足补丁测试(工程师用来作为数值解在网格细化下最优收敛性的指标)。最后,计算归结为评估包含纯几何表面面量的矩阵。本文重点研究了一阶VEM,其中与顶点相关的自由度。利用多面体元素进行拓扑优化,我们证明了成员方向的网格偏差得到了缓解。

英文摘要:

Meshing complex engineering domains is a challenging task. Arbitrary polyhedral meshes can provide the much needed flexibility in automated discretization of such domains. The geometric property of the polyhedral meshes such as the unstructured nature and the facial connectivity between elements makes them specially attractive for topology optimization applications. Numerical anomalies in designs such as the single node connections and checkerboard pattern, which are difficult to manufacture physically, are naturally alleviated with polyhedrons. Special interpolants such as Wachspress, mean value coordinates, maximum entropy shape functions are available to handle arbitrary shaped elements. But the finite elements approaches based on these shape functions face some challenges such as accurate and efficient computation of the shape functions and their derivatives for the numerical evaluation of the weak form integrals. In the current work, we solve the governing three-dimensional elasticity state equation using a Virtual Element Method (VEM) approach. The main characteristic difference between VEM and standard finite element methods (FEM) is that in VEM the canonical basis functions are not constructed explicitly. Rather the stiffness matrix is computed directly utilizing a projection map which extracts the linear component of the deformation. Such a construction guarantees the satisfaction of the patch test (used by engineers as an indicator of optimal convergence of numerical solutions under mesh refinement). Finally, the computations reduce to the evaluation of matrices which contain purely geometric surface facet quantities. The present work focuses on the first-order VEM in which the degrees of freedom associated with the vertices. Utilizing polyhedral elements for topology optimization, we show that the mesh bias in the member orientation is alleviated.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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