期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
基于向量式分析的轮轨接触模拟 被引量:2
1
作者 申莹莹 温泽峰 王衡禹 《机械》 2012年第10期1-5,74,共6页
介绍了一种新的区别于传统有限元方法的计算力学方法——向量式分析方法。在理论公式推导的基础上,通过自编程序,利用该方法对轮轨静态接触问题进行了模拟。计算结果表明,该方法得到的最大轮轨法向接触压力、接触斑大小、Von mises等效... 介绍了一种新的区别于传统有限元方法的计算力学方法——向量式分析方法。在理论公式推导的基础上,通过自编程序,利用该方法对轮轨静态接触问题进行了模拟。计算结果表明,该方法得到的最大轮轨法向接触压力、接触斑大小、Von mises等效应力与Hertz接触理论和有限元软件ANSYS结果仅相差±5%,吻合很好。向量式分析方法具有有效处理连续体大转动的优点,可为进一步模拟高速轮轨滚动接触动态行为提供很好的借鉴。 展开更多
关键词 向量式分析 牛顿第二定律 轮轨接触
下载PDF
薄壳结构碰撞、断裂和穿透行为的向量式有限元分析 被引量:6
2
作者 王震 赵阳 杨学林 《建筑结构学报》 EI CAS CSCD 北大核心 2016年第6期53-59,共7页
在向量式有限元三角形薄壳单元的基本理论中,引入薄壳结构碰撞、断裂和穿透等复杂不连续行为的模拟机制。采用"点-三角形"检测和罚接触力法模拟碰撞检测和碰撞响应,获得薄壳结构碰撞接触的全过程;采用塑性失效应变准则和质点... 在向量式有限元三角形薄壳单元的基本理论中,引入薄壳结构碰撞、断裂和穿透等复杂不连续行为的模拟机制。采用"点-三角形"检测和罚接触力法模拟碰撞检测和碰撞响应,获得薄壳结构碰撞接触的全过程;采用塑性失效应变准则和质点分裂方式,获得薄壳结构断裂和破碎的全过程;进而结合碰撞检测、碰撞响应、失效应变准则以及质点分裂处理方式,获得刚体穿透薄壳结构的全过程。基于此,编制了向量式有限元考虑薄壳结构的碰撞、断裂和穿透行为的分析程序,并通过算例分析验证了理论推导和所编制程序的有效性和可靠性,体现了向量式有限元方法在薄壳结构复杂不连续行为分析领域的优势。 展开更多
关键词 薄壳结构 向量有限元分析 碰撞接触 断裂 穿透
原文传递
TWIN SUPPORT TENSOR MACHINES FOR MCS DETECTION 被引量:8
3
作者 Zhang Xinsheng Gao Xinbo Wang Ying 《Journal of Electronics(China)》 2009年第3期318-325,共8页
Tensor representation is useful to reduce the overfitting problem in vector-based learning algorithm in pattern recognition.This is mainly because the structure information of objects in pattern analysis is a reasonab... Tensor representation is useful to reduce the overfitting problem in vector-based learning algorithm in pattern recognition.This is mainly because the structure information of objects in pattern analysis is a reasonable constraint to reduce the number of unknown parameters used to model a classifier.In this paper, we generalize the vector-based learning algorithm TWin Support Vector Machine(TWSVM) to the tensor-based method TWin Support Tensor Machines(TWSTM), which accepts general tensors as input.To examine the effectiveness of TWSTM, we implement the TWSTM method for Microcalcification Clusters(MCs) detection.In the tensor subspace domain, the MCs detection procedure is formulated as a supervised learning and classification problem, and TWSTM is used as a classifier to make decision for the presence of MCs or not.A large number of experiments were carried out to evaluate and compare the performance of the proposed MCs detection algorithm.By comparison with TWSVM, the tensor version reduces the overfitting problem. 展开更多
关键词 Microcalcification Clusters (MCs) detection TWin Support Tensor Machine (TWSTM) TWin Support Vector Machine (TWSVM) Receiver Operating Characteristic (ROC) curve
下载PDF
Characteristics of a Terrain-Following Sigma Coordinate 被引量:1
4
作者 LI Yi-Yuan WANG Bin WANG Dong-Hai 《Atmospheric and Oceanic Science Letters》 2011年第3期157-161,共5页
This study quantifies the main characteristics of a terrain-following, G-coordinate through mathematical analyses of its covariant and contravariant basis vectors as well as the vertical coordinate of σ. A 3-D schema... This study quantifies the main characteristics of a terrain-following, G-coordinate through mathematical analyses of its covariant and contravariant basis vectors as well as the vertical coordinate of σ. A 3-D schematic of the σ-coordinate in a curvilinear coordinate system is provided in this study. The characteristics of the basis vectors were broken down into their "local vector charac- teristics" and "spatial distribution characteristics", and the exact expressions of the covariant; in addition, the con- travariant basis vectors of the G-coordinate used to eluci- date their detailed characteristics were properly solved. Through rewriting the expression of the vertical coordi- nate of G, a mathematical expression of all the cr-coor- dinate surfaces was found, thereby quantifying the so- called terrain-following characteristics and lack of flexi- bility to adjust the slope variation of G-coordinate sur- faces for the classic definition of G. Finally, an analysis on the range value of the vertical coordinate demonstrated that the general value range of G could be obtained by eliminating the G-coordinate surfaces below the Earth's surface. All these quantitative descriptions of the charac- teristics of G-coordinate were the foundation for improv- ing the G-coordinate or creating a new one. 展开更多
关键词 quantitative description sigma coordinate 3-D schematic basis vectors non-orthogonal
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部