数控机床参数故障维修

数控机床参数分为CNC参数、PMC参数和伺服参数，参数的合理设置才能保证机床的稳定和精度。如果参数丢失或被改变，可能引起机床的功能缺少。误动作，或损坏工件、机床本身或人员伤害。笔者多次分析和排除参数引起的故障，现举几例供同行参考。     

潜艇耐压壳体埋弧焊过程参数计算机监测分析系统的研究

基于Windows2000，设计了潜艇耐压壳体埋弧焊过程参数计算机检测、记录和分析的软硬件系统。试验结果表明，该系统能较好地完成焊接电流和电孤电压信号的实时监测和记录，能及时捕捉到焊接参数的异常变化，能满足焊接生产长时间、不间断地实时监测和记录焊接工艺参数的需求，并能对焊接工艺参数进行分析，从而可对工艺参数的合理性进行评定。     

参数化CAD/CAE集成与应用

本文在参数化建模和基于结构参数化有限元分析思想的基础上，比航空发动机典型零件鼠笼式弹性支承为例，讨论了参数化建模、参数化有限元分析在商业软件二次开发语言UG/OPEN GRIP和APDL（ANSYS Parametric Design Language）中的实现方法，并且利用VC程度对参数进行控制，实现参数化建模、参数化有限元分析的集成，使得设计分析成为一个整体。结果表明，该法实现了CAD/CAE的结合，缩短了机械产品的设计分析周期，减少了设计分析人员的工作量。     

参数编程的一种应用

参数编程是数控机床加工编程的有益补充。参数程序可以作为一个独立的程序存在，也可以与普通的加工程序混合编制，形式自由，功能非常强大。SINUMERIK810M／T提供的这种编程手段，可帮助用户解决许多棘手问题。参数在程序中表示一个地址的数值。一个参数由地址R和最多3位数表示。在基本的结构中，控制器有300个有效的参数，它们被细分成传递参数、计算参数、依赖通道定义的参数或不依赖于通道定义的参数、中心参数。＠指令功能丰富，可以分成7个主组：＠0，用于程序结构的基本指令;＠1，程序分支;＠2，一般数据传送;＠3，从系统存储器…     

用计算机模拟渐开线齿轮范成

论述以不同参数的齿条和齿轮两种形式刀具，用AmoCAD有关绘图命令、编辑命令和操作命令模拟渐开线齿轮范成，绘制不同参数内、外齿轮范成图的方法，并提供几幅不同参数内外齿轮范成图。     

基于正交试验的半潜式风力机基础参数敏感性分析

针对OO-Star型式的半潜式风力机基础，采用正交试验设计方法来分析吃水、浮筒高度、浮筒宽度、立柱间距和立柱直径5个设计参数的敏感性。基于频域短期预报方法，选用我国南海某海域50年一遇极端条件，从稳性和运动响应两方面评估5个参数的敏感程度。分析结果表明，浮筒宽度是对排水量、垂荡运动和横摇运动最敏感的参数；立柱直径是对初稳性高、面积比和机舱加速度最敏感的参数，对垂荡运动和横摇运动较敏感；立柱间距对横摇运动和机舱加速度最敏感的另一个参数，对初稳性高和面积比较敏感；吃水对所有性能都较敏感。总体来看，基础参数对稳性和运动响应的影响是相对的，参数取值需要综合判断。     

面向微波组件信号传输的柔性绕线互联构形表征与优化设计

随着微波电路朝着高集成化、高频率、高可靠性方向发展，微波组件间的互联结构形态成为了显著影响微波电子系统性能的重要因素。针对微波模块互联结构表征不清，结构参数与传输性能关联机理不明，性能最优结构形态难以确定的问题，提出了一种面向微波组件电性能的柔性绕线互联最优构形参数确定方法，对柔性绕线互联构形进行参数化表征建模，基于影响度确定柔性绕线互联构形关键参数，试验设计确定柔性绕线互联局部最优构形参数，以试验局部最优构形参数为初值，基于粒子群算法确定面向信号传输性能的互联全局最优构形参数。算例结果表明，与初始构形参数下的回波损耗与插入损耗相比，全局最优构形参数下的回波损耗和插入损耗对应电性能分别提升了558.6%和97.8%，验证了该方法的准确性。研究结果对微波组件柔性绕线互联结构的优化设计与性能提高具有一定的指导意义和参考价值。     

浅谈自动扶梯制动参数测量方法及其研究进展

制停距离、制动减速度等参数是评估自动扶梯制动性能的重要依据，现总结了电梯检验规程和国家标准对制动参数的检验要求，分析了通过梯级标记法、扶手带标记法、旋转编码测量法、加速度积分法、数字图像检测法等测量制动参数的实现方式，从测量原理、准确度、便捷性、成本等方面综合比较了各测量方法技术特点，进一步对扶梯有载制动参数的轻载或无载测量方法进行了综述，为制动参数测量方法选择和研究提供了参考。     

PSO优化PCNN模型在图像分割中的性能分析

脉冲耦合神经网络模型参数众多，在应用时通常根据经验或实验设置。针对模型参数影响应用等问题，采用群体智能优化算法PSO优化简单脉冲耦合神经网络模型的关键参数，如耦合系数、时间衰减因子和脉冲输出的乘积系数。通过仿真实验，评价智能优化算法学习模型参数的有效性，比较分析了不同参数PCNN模型在图像分割中获得的轮廓、细节和纹理等存在差异性。     

制造工艺参数的智能优化设计方法进展

工艺参数是影响零件成形质量、性能、效率和成本的关键因素。对工艺参数进行智能优化设计是当前智能制造中的基础内容。综合对近年工艺参数智能优化的研究热点、发文量等分析，将近年来工艺参数智能优化设计的方法路径分为基于神经网络的智能优化设计、基于数学模型+智能算法的优化设计和基于专家系统(知识)的智能设计三种，分析了三种方法的国内外研究进展和特点，归纳和分析了优劣势，并提出了今后工艺参数智能优化设计的发展趋势。为工艺参数智能优化的研究提供参考基础和方向指引。     

弹性流体动力润滑的热效应

简述热弹性流体动力润滑的概念、理论的发展及其科学基础。在给出一组典型的点接触热弹流数值解之后,通过实例集中描述5种热效应,即摩擦因数与滑滚比之间的关系、入口温升导致油膜减薄、尺度效应、热黏度楔效应和固体温度效应。澄清了润滑工程界对热弹流润滑的几个模糊理解,指出热弹流研究面临的主要困难,并展望其发展前景。     

Effect of lubricant selection on EHL performance of involute spur gears

As the gear oils usually undergo shear-thinning even in the inlet zone, an accurate EHL analysis requires realistic rheological models. This is necessary for gear oil selection so as to prevent scuffing failure. This paper demonstrates the effect of rheology on the EHL characteristics of spur gears using full transient thermal EHL simulations with Carreau shear-thinning model and Doolittle's free volume based pressure-viscosity relationship. The PDMS oil considered here is found to exhibit severe film thinning with 74% thinner EHL film as compared to a moderately shear-thinning PAO oil which, on the other hand, undergoes a larger thermal reduction.     

圆锥滚子弹流润滑的热效应分析

通过数值求解研究两圆锥滚子间的热弹流润滑问题,分析弹流润滑区内压力、膜厚和温度的分布曲线,讨论热效应和滑滚比对接触区弹流润滑性能的影响。结果表明:在圆锥滚子弹流润滑中,热效应降低了滚子副的润滑性能。由于圆锥滚子几何形状的特点,沿着y轴的截面,压力、膜厚和温度的分布曲面出现斜度。滚子副的端泄使得两端润滑性能较中间恶劣,但是对滚子进行的端部修形,又使得端部和中部的差异不十分剧烈。随着滑滚比的增大,滚子副的润滑性能降低,热效应的影响增大;在纯滚动的情况下,热效应可以忽略不计。     

Thermal Elastohydrodynamic Lubrication of Ceramic Materials

ABSTRACT

The effect of thermal conductivity on point elastohydrodynamic lubrication (EHL) contacts was discussed with representative engineering ceramics and steel by a non-Newtonian thermal EHL analysis. Through this investigation, fundamentals of EHL characteristics of contact surfaces composed of different thermal conductivities were generally revealed and a combination of optimum ceramic materials has been proposed. Furthermore, when the contacting materials are the same, it has been pointed out that the equivalent elastic modulus should be rather small and the thermal conductivity of the contact material should be high to obtain a thick overall film thickness and low film pressure.     

Effects of thermally induced inhomogeneous shear and surface thermal boundary conditions on the shear stress in sliding elastohydrodynamic contacts

Numerous research work has shown that significant thermally induced cross‐film inhomogeneous shear or thermal shear localisation may be developed in sliding elastohydrodynamic lubrication (EHL) contacts with pronounced consequences. This paper uses the theoretical framework established in previous research to further analyse the effects of the shear localisation on the lubricant shear stress and thus the EHL traction. Results obtained suggest that the shear localisation significantly accelerates the thermally induced reduction of the shear stress in sliding EHL contacts. The study also shows dramatic reduction of the shear stress in EHL contacts with one‐insolated surface, which is significantly attributed to the more intensified thermal shear localisation near the insolated surface. The practical significance of the dramatic shear stress reduction is discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

Thermal transient rough EHL line contact simulations by aid of computational fluid dynamics

Reynolds equation is the pre-dominantly used PDE for modelling the fluid flow or more accurately the fluid pressure in an elastohydrodynamic lubrication (EHL) contact. The equation is derived by combining the two conservation equations of momentum and continuity into a single equation for the fluid pressure. The numerical approach for theoretical investigations performed on EHL contacts in this work is somewhat different. The modelling of the fluid flow is based on a computational fluid dynamic (CFD) technique. The fluid flow is simulated by aid of the equations of momentum and continuity in a more complete form and when the thermodynamics is incorporated, the equation of energy. The aim of the investigation was to examine whether the CFD technique could be used to handle thermal transient rough EHL line contacts. It is shown that commercial CFD software can be modified to meet such requirements. The influence of thermal effects on the flow under sliding motion was investigated. The non-Newtonian model used in this work is the Ree-Eyring model. It is shown that the choice of the Eyring stress in the model influences flow in the contacts. If the thermal properties of the surrounding solids differ, it has been shown experimentally and theoretically that a dimple or increased central film thickness may appear in the EHL contacts. This work shows that the governing mechanisms that result in the dimple are also present in thermal transient rough EHL line contacts.     

一种简化的点接触热弹流模型及其完全数值解

本文提出了一个简化的点接触热弹流计算模型并进行了完全数值求解。与现有的完全数值模型相比，采用本模型进行求解具有计算量小，精度适中的特点，更适合工程计算的要求。文中对多种工况下点接触热弹流的摩擦牵引性能和表面闪温特性进行了数值分析。     

指数率流体热弹流润滑分析

应用多重网格技术,求得了指数率非牛顿流体线接触热弹流润滑的数值解,分析了油膜压力、厚度和温度等随流变指数、速度参数、滑滚比及载荷参数的变化关系,并与相同工况下的等温解进行了比较。结果表明,随着流变指数的增加,油膜厚度和温度、入口处的当量粘度、最小膜厚、中心膜厚和最大温升均增大,而油膜压力和摩擦因数的变化较小。指数率流体弹流润滑问题的热效应不可忽略;与压缩功项相比,油膜能量方程中的热耗散项对温度的影响最大。同时,无量纲速度参数、滑滚比和载荷参数等均影响热弹流润滑特性。     

极限剪切状态下的线接触Reynolds方程

本文导出了考虑极限剪切状态的线接触流变热弹流Reynolds方程,该方程以Evans—Johnson流变模型为基础,可用于求解线接触流变热弹流润滑问题的油膜厚度、压力分布、剪应力分布和牵曳系数曲线。计算实例表明,润滑油的流变特性对弹流润滑的油膜形状和压力分布影响不大,但对Hertz接触区的剪应力分布有显著影响。     

A Review of Elasto-Hydrodynamic Lubrication Theory

The development and understanding of elastohydrodynamic lubrication (EHL) can be traced back to the beginning of the previous century. However, it was not until 1949 that the first real solution of the problem was published. Since then, the technology has evolved enormously. In the current article a summary of these developments is given. Smooth surface EHL has become well established. Numerical methods, analytical solutions, and experimental techniques have become mature. Focus areas of research today are thermal EHL, starved EHL, friction (non-Newtonian lubricants), roughness, and grease. The scope of EHL is so wide that the authors needed select the topics of focus in this article. Therefore, in addition to the general overview of the areas of friction, analytical methods, starved EHL, and grease EHL are highlighted in this article.