共查询到20条相似文献,搜索用时 156 毫秒
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飞行器RCS预估计算是隐身技术研究中的重要研究内容。论述了利用飞行器外形的特点,在满足飞行器设计误差的前提下使用平面和柱面对飞行器的整机作NURBS曲面逼近,然后用柱面和平面剖分代替曲面的剖分。实现了飞行器整机模型的指定边长的三角剖分。这种方法不同于有限元计算的网格剖分,具有网格单元与曲面曲率无关和剖分速度快等特点。 相似文献
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四阶特征值问题的各向异性有限元方法 总被引:2,自引:1,他引:1
本文的主要目的是讨论在各向异性网络剖分下四阶特征值问题的双三次Hernmite有限元逼近。由于该网格不同于传统有限元方法中的正则性剖分或拟一致剖分,在理论分析过程中不能直接使用Sobolev插值理论。本文将利用新的技巧,导出与传统网格剖分下相同的最优误差估计。 相似文献
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使用多重网格算法的一种途径 总被引:3,自引:0,他引:3
采用坐标变换方法,将物理平面中任意几何区域上的非均匀网格剖分映射到计算平面中规则区域上的均匀网格剖分,这种处理使得对某些问题的多重网格算法成为方便可行,文后给出了两个算例。 相似文献
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提出了一种球面参数化三角网格曲面的方法。结合平面凸参数化和球面参数化,计算出封闭网格的切割线边界,网格边界映射到球面的凸区域边界上。然后分别参数化各子网格,最后将三角网格内部点映射到球面上。并用实例验证了此方法的可行性和有效性。 相似文献
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为了从理论上表征平面正交织物球面成型后的几何特征, 提出基于坐标变换求解渔网模型的新方法, 确定单层正交平面织物在球面上铺覆成型后的网格位置、 织物剪切变形和纱线弯曲变形。依据弧长不变条件确定方形织物完全包覆球面后的对称面上的网格位置和局部坐标系下中间网格的位置, 利用坐标变换获得中间网格在整体坐标系成型球面上的坐标位置; 根据变形前后的网格形状确定织物面内剪切变形和两个方向纱线的弯曲曲率, 为织物的球面成型性评价提供几何参数。通过实例证明了当网格尺寸远小于球体半径时铺覆变形程度与网格 尺寸无关, 也与球体半径无关。铺覆后织物的剪切变形和纱线弯曲变形分布只与织物在球面上的球坐标位置有关。 相似文献
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Algorithms for expansion over spherical harmonics are often used in electrostatic field calculation, calculation of the density functions in quantum chemistry and calculation of molecular surfaces. It usually includes expansion over spherical harmonics of degrees to several dozens. The usual method is to use an integration method over some grid on the unit sphere and in fact is a multiplication of the matrix of values of spherical harmonics in the grid points by a vector of values of the expanding function in the set of points. This algorithm executes O(NL2) operations whereN is the number of the grid points andL is the maximal degree of the spherical harmonics involved. We provide an algorithm of complexity O(NLlog2
L) for multiplication of the matrix of values of spherical harmonics in points of an arbitrary grid on the unit sphere. The algorithm is based on interrelation between spherical harmonics and Legendre polynomials and on a fast algorithm for expansion over Legendre polynomials. 相似文献
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Technical Physics Letters - The adsorption of barium atoms on C and Si faces of 3C-, 6H-, and 4H-SiC polytypes is examined using the Haldane–Anderson model. The charge transfer from a barium... 相似文献
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Oleg Vorobiev 《International journal for numerical methods in engineering》2012,90(2):243-268
The common‐plane (CP) algorithm is widely used in the discrete element method to model contact forces between interacting particles or blocks of rock. A new simple contact algorithm, similar to the CP algorithm, is proposed to model discontinuities such as joints, faults and material interfaces in an explicit finite difference code. The CP is defined as a plane separating interacting faces of grid cells, instead of blocks or particles used in the original CP method. The new method does not require iterations even for very stiff contacts. It is very robust and easy to implement, both in 2D and 3D parallel codes. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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With the continuous evolution of smart grid and global energy interconnection technology, amount of intelligent terminals have been connected to power grid, which can be used for providing resource services as edge nodes. Traditional cloud computing can be used to provide storage services and task computing services in the power grid, but it faces challenges such as resource bottlenecks, time delays, and limited network bandwidth resources. Edge computing is an effective supplement for cloud computing, because it can provide users with local computing services with lower latency. However, because the resources in a single edge node are limited, resource-intensive tasks need to be divided into many subtasks and then assigned to different edge nodes by resource cooperation. Making task scheduling more efficient is an important issue. In this paper, a two-layer resource management scheme is proposed based on the concept of edge computing. In addition, a new task scheduling algorithm named GA-EC(Genetic Algorithm for Edge Computing) is put forth, based on a genetic algorithm, that can dynamically schedule tasks according to different scheduling goals. The simulation shows that the proposed algorithm has a beneficial effect on energy consumption and load balancing, and reduces time delay. 相似文献
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针对在数据网格中创建多副本虽可有效提升下载速度、降低网络流量,但多副本创建会带来大量存储开销和网络流量开销,以及基于GridFTP协议的各种并行下载算法虽可进一步提升下载速度,但仍不能解决多副本对存储空间和网络流量的影响的问题,提出了一个能保证数据的完整性、存储的可靠性和降低存储空间的数据网格存储模型,并基于该存储模型和GridFTP协议,提出了一个并行下载调度算法。实验表明,该算法只需要较少的冗余便可达到现有的针对全副本的并行下载算法可达到的理想下载速度,取得较好的效果,实现并行快速传输、节约存储空间和降低网络流量的目标。 相似文献
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The paper considers grid computing systems in which the resource management systems (RMS) can divide service tasks into subtasks and send the subtasks to different resources for parallel execution. In order to provide desired level of service reliability the RMS can assign the same subtasks to several independent resources for parallel execution.The service reliability and performance indices are introduced and a fast numerical algorithm for their evaluation for arbitrary subtask distribution in grid with star architecture is presented. This algorithm is based on the universal generating function technique.Illustrative examples are presented. 相似文献
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Jiing-Yih Lai Chun Wong Thanh Thuong Huynh Ming-Hsuan Wang Chia-Hsiang Hsu Yao-Chen Tsai 《中国工程学刊》2016,39(6):735-745
In mechanical design, small blending is a common operation used to improve the strength and aesthetics of the workpiece. In blending operations, certain smooth faces are added to the boundary representation (B-rep) model to smooth sharp edges and vertices. These faces are termed ‘blend faces.’ However, they may affect the quality of analysis; these faces should be meshed with tiny meshes, which may result in an increase in computational time and reduced accuracy of simulation results. Hence, small blend suppression is an approach for improving the quality of generated meshes. Blend suppression is a technique for reverting a blended computer-aided design model to its original unblended status. This study proposes a blend suppression algorithm for removing blend faces in computer-aided engineering (CAE) analysis. The proposed algorithm operates as follows: (1) edge blend faces and vertex blend faces are grouped individually, (2) new geometric data are computed, (3) new elements are added to the data structure of the B-rep model, (4) all data related to blend faces are deleted, and (5) all topological data in the B-rep model are updated. Several examples are presented in this paper to demonstrate the feasibility of the proposed method for blend suppression as well as its advantage in improving the quality of meshes in CAE analysis. 相似文献