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基于两面投影为全等几何图形的组合体构型设计 被引量:4
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作者 孟祥宝 王彦鹍 董正荣 《图学学报》 CSCD 北大核心 2018年第3期599-604,共6页
组合体投影分析与构型设计是工程图学课程的基本内容之一,是工程师阅读工程图样和设计零件几何结构细节的基础。为此,通过一系列示例,提出一种基于等腰三角形、等腰直角三角形、正方形、圆形及方圆组合组成的全等几何图形作为两面投影,... 组合体投影分析与构型设计是工程图学课程的基本内容之一,是工程师阅读工程图样和设计零件几何结构细节的基础。为此,通过一系列示例,提出一种基于等腰三角形、等腰直角三角形、正方形、圆形及方圆组合组成的全等几何图形作为两面投影,以棱柱、棱锥、圆柱、圆锥、圆球和圆环等基本单元通过线面/形体分析法进行空间发散构思进而派生多种组合体及其第三面投影,并用CATIA软件建立对应的三维几何模型。该方法为拓展空间思维能力和几何构型设计提供了基本素材,增强了投影分析过程的逻辑性和趣味性。 展开更多
关键词 组合体 投影分析 构型设计 空间思维能力 CATIA
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Bayesian zero-failure reliability modeling and assessment method for multiple numerical control(NC) machine tools 被引量:2
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作者 阚英男 杨兆军 +3 位作者 李国发 何佳龙 王彦鹍 李洪洲 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第11期2858-2866,共9页
A new problem that classical statistical methods are incapable of solving is reliability modeling and assessment when multiple numerical control machine tools(NCMTs) reveal zero failures after a reliability test. Thus... A new problem that classical statistical methods are incapable of solving is reliability modeling and assessment when multiple numerical control machine tools(NCMTs) reveal zero failures after a reliability test. Thus, the zero-failure data form and corresponding Bayesian model are developed to solve the zero-failure problem of NCMTs, for which no previous suitable statistical model has been developed. An expert-judgment process that incorporates prior information is presented to solve the difficulty in obtaining reliable prior distributions of Weibull parameters. The equations for the posterior distribution of the parameter vector and the Markov chain Monte Carlo(MCMC) algorithm are derived to solve the difficulty of calculating high-dimensional integration and to obtain parameter estimators. The proposed method is applied to a real case; a corresponding programming code and trick are developed to implement an MCMC simulation in Win BUGS, and a mean time between failures(MTBF) of 1057.9 h is obtained. Given its ability to combine expert judgment, prior information, and data, the proposed reliability modeling and assessment method under the zero failure of NCMTs is validated. 展开更多
关键词 Weibull distribution reliability modeling BAYES zero failure numerical control(NC) machine tools Markov chain Monte Carlo(MCMC) algorithm
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