大直径大导程多头梯形内螺纹的数控加工

介绍了用数控化改造后的CQ5250立车设备,加工大直径零件上的大导程多头梯形左旋内螺纹的加工方法.阐述了螺纹车刀的选用、螺纹分度法的确定、螺纹加工工艺的确定、螺纹的数控加工程序,以及叶轮硬化后使用轴头螺纹规修螺纹的方法.     

大导程梯形螺纹的数控车加工技术研究

为了解决大导程梯形螺纹车削加工难点,提高大导程梯形螺纹加工质量的稳定性,提高加工产品的经济性,从完善加工工序(选择加工方法、加工设备、装夹方案、刃磨刀具)、编制宏程序及选择切削要素入手,确定了大导程梯形螺纹的最优加工方案。这将对螺纹车削的加工工艺优化及高可靠性轴类零部件的制造具有理论指导意义。     

运用宏程序车削大导程非标准梯形螺纹的方法

大导程非标准梯形螺纹的加工是数控车削的一个难点.由于导程大走刀速度快,切削深度较深,切削抗力较大,而且精度要求较高,如果用简单的指令很难车削大导程的非标准梯形螺纹.介绍一种实用、高效的运用宏程序在数控车床加工非标准梯形螺纹的车削方法.     

大直径大导程多头梯形内螺纹的数控加工

介绍了采用数控化改造的CQ5250立车设备,加工大直径零件上的大导程多头梯形左旋内螺纹的加工方法。阐述了螺纹车刀的选用、螺纹分度法的确定、螺纹加工工艺的确定、螺纹的数控加工程序，以及叶轮硬化后使用轴头螺纹规修螺纹的方法。利用该数控加工方法加工叶轮上的螺纹，既能够保证螺纹的加工精度，又可以减少刀具重磨和重定位次数，缩短辅助时间，提高生产效率。     

大螺旋升角多头梯形螺纹加工方法探讨

为解决某产品的大螺旋升角多头梯形螺纹加工的技术难题,就几种加工方法进行了分析比较,通过优选加工方法,并使用为此设计的专用辅助工具,完成了大螺旋升角多头梯形螺纹的加工,对使用相同方法加工的内、外螺纹进行配合及功能试验,验证了加工的多头螺纹可以达到设计要求。     

数控车削梯形螺纹的两种编程方法

在数控车床上用简单的指令如G32、G82、G76很难一次性车削较大导程的梯形螺纹，加工梯形螺纹时，由于螺距过大进给切削力太大编程困难，所以，文中从编程方法方面讨论了两种车削梯形螺纹的方法。     

车多头螺纹自动分头拨盘

车削多头螺纹或多头蜗杆,是车床加工中经常性的工作。选择合理的分头方法,是减少螺距(周节)误差,提高加工精度和工作效率的关键环节。为此,我们自己设计制作了车多头螺纹自动分头拨盘装置,实现了车削大导程多头螺纹或多头蜗杆的分头自动化。经过几年来的生产实践,证明效果良好。现在简介如下:车制多头螺纹自动分头拨盘装置分为自动分头拨盘和换向辅助器两个部     

经济型数控车床加工螺纹的改造方法

采用西安微电机研究所生产的JWK—2—3C总线机数控系统,和陕西省机械研究所提供的机械改造配件,对CA6140类车床进行改造。使用效果非常好,但改造后的车床,螺纹功能的最大导程,一般为12～20mm。改造前的CA6140类车床螺纹加工最大导程可达192mm。改造后的车床加工螺纹的导程从20～192mm段成为空白。使经济型数控机床的使用范围受到限制,无法完成大导程螺纹、多头蜗杆、拉     

多头大导程ACME螺纹副的数控车参数化编程

介绍了多头大导程美制一般用途ACME螺纹副的数控车削加工工艺,并运用变量控制对其进行参数化编程。此程序适用于该类螺纹所有代号的外、内及右、左旋向螺纹的数控车削,具有标准化、高效程、准确性等特点。     

螺纹数控车削编程方法的研究

介绍了应用数控车削加工等螺距、变导程、多头等螺纹的方法与特点,分析和总结了针对各种不同螺纹加工的数控指令、编程方法及加工技巧。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...