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1 问题的提出 我厂装载机后车架镗加工是在卧式镗床T612上完成的,在加工过程中存在如下问题:① 需要刮削的四个端面间距尺寸(609)过大(图1),刀杆伸出量过长;② 刮削端面尺寸(Φ 145)较大,由于刀头切削部分伸出较长且受刀杆刚度影响,刮削端面时切削力较大,产生切削颤动,刮出的表面粗糙,且两平行表面加工后产生内凹现象(见图2),使装配后的连接盘无法压紧孔内的关节轴承,造成装载机在工作过程中关节轴承上下窜动,铰接销磨损严重,关节轴承碎裂现象时有发生,更甚者导致后车架铰接孔磨大,造成车架的报废。因此,保证… 相似文献
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在使用AutoCAD绘图软件绘制各类图形的工作中。最后一个阶段是将图形文件最终在打印机、绘图机上输出为图纸。其中图形线条的粗细划分是一项必须认真对待的工作。由于一般图纸上的图形不能像在彩色显示器上可用颜色及深浅区分图索、结构,而只能以改变线条的粗细的方法来达到这个目的。因此,划分好图形中线条的粗细既有利于区分图形要素,又有利于准确表达设计意图及方便识图。尤其是工程图纸,应按照国家制图标准,将图中的各图素划分出明显的粗细来。这样图纸方能满足标准化的要求。实际上线条的粗细从粗到细有多种变化,在计算机图形… 相似文献
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本文简述了当前信息网络安全内涵已发生根本变化,网络安全问题从一般性的防卫变成了一种非常普通的防范,并结合一销公司网络现状,阐述了本公司网络的防护措施。 相似文献
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近年来,随着机床结构的不断改进,机床及工件夹具刚性的提高,刀具材料的进步,特别是涂层技术的发展,使得刮齿的加工质量及稳定性日益提高,逐渐成为小模数淬硬齿轮精加工中成熟的工艺,国外许多企业已逐渐采用刮齿替代磨齿作为精加工方法.介绍刮齿工艺的工作原理和工艺特点,结合典型硬齿面齿轮零件,论述刮齿工艺在工程机械变速器硬齿面齿轮加工中的应用. 相似文献
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S. D. Rajan S.-W. Chin L. Gani 《Computer-Aided Civil and Infrastructure Engineering》1996,11(4):259-274
Abstract: Design optimization methodologies for sizing and shape optimal design have undergone an evolutionary process over the last two decades. The motivation behind the changes is to develop a methodology with no practical limitations on the nature and size of the problem that can be solved. In this research, a personal computer-based shape optimal design system is developed with particular attention to robustness, generality, efficiency, and pre- and postprocessing. To achieve these objectives, the hybrid natural shape optimization approach is developed and used with adequate control over the velocity field matrix generation. User control over model creation and mesh generation makes it possible to minimize mesh distortion and the need for remeshing. Design sensitivity expressions using the implicit differentiation method are derived. It is shown that the analytical derivatives can be computed efficiently for a variety of functions. Numerical examples are solved to illustrate the developed methodology using a software system developed under the MS-DOS operating system. 相似文献
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利用有限元分析软件ANSYS ,对硬齿面刮削铣刀头进行了结构参数的优化分析 ,通过铣刀头在各种改变参数条件下的应力分布图和变形图 ,预知刀盘切削时的应力应变状态 ,了解刀具几何参数对刀具强度、刚度等的影响规律 ,从刀具力学的角度找出刮削刀头易崩刃破损的结构因素 相似文献
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在液压阀结合平面上经常有O形密封圈,安装O形密封圈的沉孔直径和深度尺寸精度要求都比较高(如图1所示),普通锪钻不易精确控制。使用车床、镗床等通用设备进行加工,效率低下,加工精度不易保证。为了解决这一问题,笔者设计了一种专用工装,其结构如图2所示。该工装由限位套2、刀头3、轴承外壳4、推力轴承5、深沟球轴承6、轴承压盖7、垫圈8、主轴9和螺钉10组成。硬质合金刀片焊接在刀头上。刀头的切削角度:前角γ=0°,后角α=5°,副后角α1=0°(见图3)。加工钢件时,为了减小刀具与工件之间的摩擦,副后角α1=2°~5°,并倒棱。制作时应保证刀头… 相似文献
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Shekhar Govind Siamak A. Ardekani & Ali Kazmi 《Computer-Aided Civil and Infrastructure Engineering》1999,14(4):299-307
A quick-response PC tool has been developed to address a number of crucial transportation needs following major road incidents or urban disasters. Known as TEMPO (Transportation Emergency Management of Post-Incident Operations), the tool is capable of instantaneously identifying near-optimal traffic-diversion strategies around disruptions in an urban traffic network. TEMPO utilizes heuristic approaches to estimating the origin-destination (O-D) of the traffic on the closed links and reassigning the estimated O-D to the remainder of the network.
This article describes the following features of TEMPO: (1) the GIS-based data structure that allows graphic user interaction and network editing, including closed street links, changes in number of lanes, cordoned off areas, changes in street directionality, speed limits, and parking regulations, and (2) the algorithm for traffic diversion around the incident based on cordoning the affected region around the closure, estimation of the O-D matrix for the traffic on the closed links, and reassignment of the O-D to the network. Finally, a simulation-based calibration procedure is conducted to compare the TEMPO results with those generated by a popular planning software, TRANPLAN. Thirty-three incident scenarios in a generic test network are simulated by both TEMPO and TRANPLAN, and the results are compared statistically. 相似文献
This article describes the following features of TEMPO: (1) the GIS-based data structure that allows graphic user interaction and network editing, including closed street links, changes in number of lanes, cordoned off areas, changes in street directionality, speed limits, and parking regulations, and (2) the algorithm for traffic diversion around the incident based on cordoning the affected region around the closure, estimation of the O-D matrix for the traffic on the closed links, and reassignment of the O-D to the network. Finally, a simulation-based calibration procedure is conducted to compare the TEMPO results with those generated by a popular planning software, TRANPLAN. Thirty-three incident scenarios in a generic test network are simulated by both TEMPO and TRANPLAN, and the results are compared statistically. 相似文献
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R. Bruce Ricks 《Journal of the American Planning Association. American Planning Association》2013,79(2):117-120
HOUSING SUBSIDIES IN THE UNITED STATES AND ENGLAND: by Daniel R. Mandelker: Bobbs-Merrill Company, Inc., Indianapolis, Indiana, 1973. 246 pp. $9.50 HOUSING THE URBAN POOR: A CRITICAL EVALUATION OF FEDERAL HOUSING POLICY: by Arthur Solomon MIT Press, Cambridge, Massachusetts, 1974. 227 pp. $12.00 (Cloth) ECONOMIC ASPECTS OF TELEVISION REGULATION: by Roger G. Noll, Merton J. Peck and John J. McGowan: The Brookings Institution, Washington, D.C., 1973. 342 pp. $8.95 (Cloth) AERIAL PHOTOGRAPHY AND CITY PLANNING: by Jean-Pierre Muret (editor), et. al: International Federation for Housing and Planning (IFHP); Centre de Reicherche d'Urbanisme (CRU), 1972, 226 pp. TWO BRAZILIAN CAPITALS: ARCHITECTURE AND URBANISM IN RIO DE JANEIRO AND BRASILIA: by Norma Evenson: Yale University Press, New Haven, Connecticut, 1973. 225 pp. (Cloth) KOMMUNALE ENTWICKLUNGANALYSE UND STADTEBAULICHE KALKULATION (Analysis of Municipal Development and Financial Evaluation of Urban Growth: A Study Related to Small Town Planning: By Herbert Grabe: Karl Kramer, Verlag, Stuttgart, 1970. 152 pp. 67 illustrations, 69 tables. DM 38.-(PB) OPENING UP THE SUBURBS: ON URBAN STRATEGY FOR AMERICA: by Anthony Downs Yale University Press, New Haven, Connecticut, 1973. 229 pp. $7.95 (Cloth) 相似文献
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《Planning》2013,(3):57-60
提出一种利用核磁T2谱结合数字岩心技术计算岩石粒度分布的方法。岩石粒度分布近似符合Weibull分布,改变分布参数可得到不同粒度分布。给出初始Weibull分布后采用过程法构建数字岩心,并用随机行走法对构建的数字岩心进行核磁数值模拟,遍历分布参数区间使模拟得到T2谱与试验T2谱逼近,误差最小时获得的Weibull分布即为岩石粒度分布。最后根据实际核磁测井资料对井下岩石粒度进行连续计算,粒度计算结果与实验室粒度分析结果对比良好,验证了方法准确性。 相似文献
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本文在Paloheimo和Hannus研究的基础上,提出了一个可供设计应用的结构可靠度的实用分析方法,用来求解含有非正态变量的极限状态方程的安全指标β以及在已知目标安全指标β_K时直接求解抗力平均值μ_R或特征值R_K。计算表明,与国际结构安全度联合委员会(JCSS)采用的需要反复迭代求解的Rackwitz-Fiessler方法相比,可使计算得到简化。 相似文献
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《Soils and Foundations》2002,42(3):107-113
The simplest convex conical surface in the principal stress space is proposed in this article, relaxing the requirement that the frictional angles in the triaxial compression and extension states coincide with each other. It could be adopted as the equation of the critical state surface which is incorporated into the yield/loading surface in elastoplastic constitutive equations of soils. Also, it could roughly describe the failure surface of soils although the failure surface is not a material property, depending on loading conditions, i.e. the drained (volume change) or the undrained (constant volume), the constant lateral stress or the constant mean stress, etc. 相似文献