NEW INSIGHTS INTO PRINCIPLES FOR DESIGNING ARCHITECTURE OF ENVIRONMENT SYSTEM FOR TOOL INTEGRATION ─IN THE CASE OF PRODUCTION MACHINES DESIGN

ＮＥＷＩＮＳＩＧＨＴＳＩＮＴＯＰＲＩＮＣＩＰＬＥＳＦＯＲＤＥＳＩＧＮＩＮＧＡＲＣＨＩＴＥＣＴＵＲＥＯＦＥＮＶＩＲＯＮＭＥＮＴＳＹＳＴＥＭＦＯＲＴＯＯＬＩＮＴＥＧＲＡＴＩＯＮ─ＩＮＴＨＥＣＡＳＥＯＦＰＲＯＤＵＣＴＩＯＮＭＡＣＨＩＮＥＳＤＥＳＩＧＮＺｈａ...     

THE CADD AND SIMULATION SYSTEM OFTHE NEW-TYPE GEAR

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CURVE AND SURFACE INTERPOLATIONBY SUBDIVISION ALGORITHMS

ＣＵＲＶＥＡＮＤＳＵＲＦＡＣＥＩＮＴＥＲＰＯＬＡＴＩＯＮＢＹＳＵＢＤＩＶＩＳＩＯＮＡＬＧＯＲＩＴＨＭＳＲｕｉｂｉｎＱｕＣＵＲＶＥＡＮＤＳＵＲＦＡＣＥＩＮＴＥＲＰＯＬＡＴＩＯＮＢＹＳＵＢＤＩＶＩＳＩＯＮＡＬＧＯＲＩＴＨＭＳ￥ＲｕｉｂｉｎＱｕＡｂｓｔｒａ...     

乘同余伪随机数序列的二维结构分析

乘同余伪随机数序列的二维结构分析罗平（武汉交通科技大学）ＯＮＴＨＥＴＷＯ－ＤＩＭＥＮＳＩＯＮＡＬＳＴＲＵＣＴＵＲＥＯＦＴＨＥＳＥＱＵＥＮＣＥＯＦＲＡＮＤＯＭＮＵＭＢＥＲＳＧＥＮＥＲＡＴＥＤＢＹＭＵＬＴＩＰＬＩＣＡＴＩＶＥＣＯＮＧＲＵＥＮＴＩＡＬＧＥＮ...     

CAD系统二次开发语言的设计与实现

ＣＡＤ系统二次开发语言的设计与实现王建民，孙家广（清华大学计算机科学与技术系北京１０００８４）ＤＥＳＩＧＮＡＮＤＩＭＰＬＥＭＥＮＴＡＴＩＯＮＯＦＴＨＥＦＵＲＴＨＥＲＤＥＶＥＬＯＰＭＥＮＴＬＡＮＧＵＡＧＥＯＦＣＡＤＳＹＳＴＥＭＳ￥ＷａｎｇＪｉａｎｍｉｎ...     

基于方块脉冲函数逼近的线性连续回归模型的参数估计及其应用

基于方块脉冲函数逼近的线性连续回归模型的参数估计及其应用赵明旺（武汉钢铁学院）ＰＡＲＡＭＥＴＥＲＥＳＴＩＭＡＴＩＯＮＦＯＲＬＩＮＥＡＲＣＯＮＴＩＮＵＯＵＳＲＥＧＲＥＳＳＩＶＥＳＹＳＴＥＭＳＶＩＡＢＬＯＣＫＰＵＬＳＥＦＵＮＣＴＩＯＮＳＡＮＤＩＴＳＡＰＰ...     

FRAMEWORK OF A DISTRIBUTED ENGINEERING DBMS

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A FEATURE－BASED PRODUCT MODELLING SYSTEM ON PC （CASE STUDY OF PARTS DESIGN FOR PRESS MACHINE）

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A CAD SYSTEM FOR CARPET DESIGN

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CASE STUDY OF CAD/CAPP INTEGRATION FOR ROTATIONAL PARTS

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Structural topology optimization with constraints on multi-fastener joint loads

This paper addresses an important problem of design constraints on fastener joint loads that are well recognized in the design of assembled aircraft structures. To avoid the failure of fastener joints, standard topology optimization is extended not only to minimize the structural compliance but also to control shear loads intensities over fasteners. It is shown that the underlying design scheme is to ameliorate the stiffness distribution over the structure in accordance with the control of load distributions over fastener joints. Typical examples are studied by means of topology optimization with joint load constraints and the standard compliance design. The effects of joint load constraints are highlighted by comparing numerical optimization results obtained by both methods. Meanwhile, resin models of optimized designs are fabricated by rapid prototyping process for loading test experiments to make sure the effectiveness of the proposed method.     

有砟轨道扣件缺失识别算法的研究

针对有砟轨道扣件缺失问题,提出了基于fast PCA 和bag of words的两级分类扣件图像缺失识别算法。考虑到算法的可移植性和拍摄角度的不同,图像中钢轨和轨枕的方向并不一定是垂直的,单扣件定位识别具有局限性,提出采用双扣件图像作为样本。通过第一级分类器判断扣件是否缺失,进而得到扣件的具体位置。通过第二级分类器判断缺失扣件的类型,进一步得到扣件缺失的数目。该识别算法可达到较好的识别效果,有效地解决了拍摄角度不同的情况下有砟轨道缺失扣件的检测问题。     

基于局部特征和语义信息的扣件图像检测*

针对现有底层特征识别扣件状态的算法存在描述能力差、错误率高等问题,提出一种基于扣件局部特征和语义信息的扣件检测模型。首先,在图像的非线性空间中计算扣件底层局部特征来表达扣件轮廓信息。然后,将图像分为4个子图,有效克服了由于扣件左右对称、上下相似造成的单词多义性问题。再根据扣件子图构造视觉单词,由底层特征整合得到语义信息向量。最后,以该向量训练分类器,判断待检扣件状态。对均衡的扣件样本进行测试,漏检率仅为0.67%。实验表明所提算法较现有方法,漏检率和误报率明显降低,检测能力增强。     

Pattern optimization of eccentrically loaded multi-fastener joints

For structural joints subject to dynamic loading, the fatigue strength is controlled by local stresses. For steel plate structures joined with fasteners, fatigue is governed by local friction and slip near the fasteners. As a working hypothesis for this study, a “weakest link” approach has been adopted. An optimum fastener pattern is attained by reducing the shear load in the most severely loaded fastener in the group. In this study, a typical eccentric multi-fastener bracket-to-beam joint was studied using constrained geometric optimization. Alternate assumptions concerning the distribution of the direct shear force between fasteners in a group were assessed. An analytical expression for non-uniform direct shear force resulted in an optimized fastener pattern with approximately 20% lower von Mises equivalent strain. The comparative finite element method based topology optimization analysis resulted in a contour, which was in close agreement with the fastener pattern attained analytically by exploiting geometry optimization.     

Computer analysis of fastener load distribution in a multi-row joint

The fastener load distribution in a multi-row joint was investigated and general equations were obtained. The effects of essential parameters considered in the joint design on the fastener load distribution were analyzed and computer solutions were obtained. The results indicated that the fastener load at the end rows can be adequately reduced when the effects of the parameters were jointly analyzed. The method of equal partition of load among rows of fasteners, including the effect of friction, was developed.     

Multirow joint fastener load investigation

A multirow joint subjected to the mechanical and thermal loadings was investigated to determine the loads taken by the fasteners in each row. The hole clearance was considered and its effect on the thermal expansion was defined. The friction in the interface between two plates in contact was analyzed and its effect on the distribution of fastener loads was determined. The primary joint design parameters, such as the material and size of the plates and of the fasteners and the patterns of fastener arrangement were considered. The principle of complementary virtual work was employed to derive the general equations involving these parameters, and the analytical solutions were obtained by solving the matrix equations. A computer program was developed to obtain the numerical solutions through the use of FORTRAN IV System 370/165 computer techniques. The application of the computer program to the practical joint design problems is discussed.     

基于边缘特征的无砟轨道扣件定位方法

轨道扣件的精确定位是实现扣件缺陷检测的前提,而常规的基于机器视觉的轨道扣件定位检测方法存在适应性差,且易受光照强度及遮挡的干扰。为了实现轨道扣件的快速精确定位,提出一种基于边缘特征的轨道扣件定位方法。通过在参考图像中选取标准扣件区域以生成匹配模板,利用Canny边缘滤波算子获得边缘点的位置坐标及梯度方向;在此基础上构建搜索模型并采用图像金字塔匹配搜索策略,获得匹配分值的潜在匹配点;并利用匹配阈值设定法,逐层逐次跟踪潜在匹配点,直至图像金字塔最底层,以提高定位速度;基于最小二乘法调整位姿参数,使其达到亚像素级精度。实验表明,该方法具有鲁棒性强、定位速度快且不受光照变化及遮挡的影响,定位精度达到1/15像素,定位成功率大于95%,满足无砟轨道扣件定位需求。     

紧固件稳健性设计对动力总成悬置强度影响

在动力总成悬置的开发过程中,悬置支架分析计算满足设计要求,但台架和路试中却出现断裂的情况时有发生,紧固件是影响其计算精度的重要因素之一.通过有限元法研究紧固件安装顺序对发动机悬置仿真精度的影响;通过六西格玛方法研究紧固件的稳健性设计对发动机悬置仿真精度的影响;基于所得出的结论对悬置支架进行方案优化,并对优化后的结果进行仿真和试验验证,结果表明在发动机悬置的设计中夹紧力对仿真精度有重要影响.对采用六西格玛设计的最小紧固件加紧力进行仿真计算是一种最稳健的设计.     

基于信息熵加权词包模型的扣件图像检测

针对传统“视觉词包模型”在进行铁路扣件检测时忽略图像结构而导致的区分能力不强的问题,提出一种基于信息熵加权词包模型的扣件检测模型EW_BOW。在传统“视觉词包模型”的基础上,引入信息熵对扣件图像局部区域的词包模型的词频进行加权处理,加强词包模型对不同类别扣件的区分性,并利用潜在狄利克雷分布学习扣件图像的主题分布。最后,采用支持向量机对扣件进行分类识别。对四类扣件图像的分类实验证明该模型能够有效提高扣件分类精确度。     

基于图形软件EGS的用户界面的设计

EGS是运行于多种工作站环境的图形软件,它同时包括用于用户界面设计的基本的窗口工具。本文在介绍EGS的设计背景和功能特点的基础上,根据用户界面的基本模型和设计原则,结合集成化电子CAD系统(EDCADS)和工程数据库管理系统(EDBMS/2)等系统的用户界面的设计和实现,提出了满足实用性和可移植性的图形软件和用户界面的设计方法。