一种CAD系统组件模型的组合技术及其实现

当前CAD系统中采用的组件模型主要有两类：标准组件模型和自定义组件模型。尽管这两种情况都有成功的例子，但是不能完全照搬成功经验。在分析了当前CAD开发中面临的挑战后，讨论了组件模型的选择策略，并给出了一个较好的解决方案——在标准组件模型的基础上增加一些新的特征和技术。最后，提出和实现了一个在COM组件模型基础上组件复用和扩展的新技术。     

基于Inventor的三维CAD软件的二维表达问题

基于Inventor讨论了三维CAD软件在创建二维工程图时所出现的各种问题,并给出了相应的解决办法。论述了二维表达的重要性,并指出,三维软件在创建二维工程图时还存在不少的缺陷。因此,由三维模型转换为符合国家标准的二维工程图不是轻而易举的事情,会遇到许多问题,需要具备扎实的二维图形的表达能力。     

逆向工程中的鞋楦模型重建与楦面展开

在分析我国制鞋工业现状和发展的基础上,运用逆向工程方法,通过获取鞋楦表面的点云数据和进行点云数据的预处理,建立了鞋楦表面的数字化模型。然后进行楦面展开,从网格划分方式和展开基点位置两方面进行了精度分析,获得了满意的展开样板。运用Imageware逆向工程软件实现了鞋楦模型重建,通过对UG软件的二次开发完成了楦面展开。     

TLU训练在矿山CAD计划编制系统中的应用

人工神经网络的应用日趋广泛,如何能够更好地应用于矿山生产实践中也成为当前业界的一个课题。通常矿山的计划系统不能够将相关的计划量数据动态地显现给用户。通过对矿山CAD系统的分析,利用人工神经网络中TLU训练原理应用VC 开发出了相应的CAD模块,将露天矿山生产计划指标动态显示。应用该模块编制计划提高了生产计划编制水平和编制效率。文中所提出的方法已经成功用于金堆城和洛钼集团矿山中,实践证明TLU训练原理很好地解决了矿山计划中的交互难题。     

基于Web Services的协同工作模块的设计和实现

本文分析了使用Web Services建立协同工作模块的可行性和优缺点,提出了基于Web Services的协同工作模块模型,并且通过应用实例验证了模型的有效性.该模型在扩展性、重用性、可靠性方面表现出色,而且支持异构平台.     

Three‐dimensional Coons macroelements: application to eigenvalue and scalar wave propagation problems

This paper discusses the matter of using higher order approximations in three‐dimensional problems through Coons macroelements. Recently, we have proposed a global functional set based on ‘Coons interpolation formula’ for the construction of large two‐dimensional macroelements with degrees of freedom appearing at the boundaries only of the domain. After successive application in many engineering problems, this paper extends the methodology to large three‐dimensional hexahedral macroelements with the degrees of freedom appearing at the 12 edges of the entire domain in case of smooth box‐like structures. Closed‐form expressions of the global shape functions are presented for the first time. It is shown that these global shape functions can be automatically constructed in a systematic way by arbitrarily choosing univariate approximations such as piecewise‐linear, cubic B‐splines, Lagrange polynomials, etc., along the control lines. Moreover, the mechanism of adding facial and internal nodes is presented. Relationships with higher order p‐methods are discussed. Following to excellent results previously derived for the solution of the Laplace equation as well as static and eigenvalue extraction analysis of structures, the paper investigates the performance of Coons macroelements in 3‐D eigenvalue and scalar wave propagation problems by implementing standard time‐integration schemes. Copyright © 2005 John Wiley & Sons, Ltd.     

浅析计算机辅助隧道施工图设计及其信息管理系统的开发

本文按用户至上的原则,采用结构化、模块化的设计方法,自顶向下对系统进行了全面分析,论述了计算机辅助隧道施工图设计及其信息管理系统的开发环境、主导思想、数据结构、信息流程、结构功能模块及程序实现过程等。     

CAD多媒体教学网络设计

首先在CAD计算机辅助设计教学过程的基础上,提出利用计算机多媒体教学网与CAD的网络功能,加强并提高CAD的教学手段,组建一套CAD多媒体教学网,从而达到提高教学质量的目的,最后提供了一套完整的多媒体教学网络的设计和调试方案。     

Genetic algorithms in computer aided design

Design is a complex engineering activity, in which computers are more and more involved. The design task can often be seen as an optimization problem in which the parameters or the structure describing the best quality design are sought.Genetic algorithms constitute a class of search algorithms especially suited to solving complex optimization problems. In addition to parameter optimization, genetic algorithms are also suggested for solving problems in creative design, such as combining components in a novel, creative way.Genetic algorithms transpose the notions of evolution in Nature to computers and imitate natural evolution. Basically, they find solution(s) to a problem by maintaining a population of possible solutions according to the ‘survival of the fittest’ principle. We present here the main features of genetic algorithms and several ways in which they can solve difficult design problems. We briefly introduce the basic notions of genetic algorithms, namely, representation, genetic operators, fitness evaluation, and selection. We discuss several advanced genetic algorithms that have proved to be efficient in solving difficult design problems. We then give an overview of applications of genetic algorithms to different domains of engineering design.     

C2连续近似弧长参数化曲线

§1.引言 一条参数曲线r:r=r(t),t∈[a,b]化为它自身的弧长为参数的过程称为弧长参数化,弧长参数化在参数曲线理论、CAD等中都有重要的应用价值。 理论上,参数曲线Γ:r=r(t)的弧长参数化由其弧长公式