10 MN水压机液压系统故障树分析

故障树分析法是系统可靠性、安全性分析的重要方法之一,本文以主缸动作无力这一事故为顶事件,建立水压机系统的故障树图,并分析提出提高整个液压系统运行可靠性的改进措施。     

10MN水压机控制系统更新及可靠性研究

针对旧水压机存在的严重缺陷与故障,对旧水压机进行FTA和FMECA分析,确立提高系统可靠性的措施,采用先进的逻辑插装阀和电液比例阀及PLC控制系统取代原有操作系统,并增加了压边机构和压边力控制系统,对新压机控制系统建立了可靠性模型,进行了可靠性分配和可靠性预计,根据应力-强度干涉模型,利用大型有限元软件对主工作缸等主要液压元件的应力进行了可靠性分析,为控制系统的设计提供了参考依据。利用现场调试作为可靠性增长试验,验收试验作为连续型定时截尾可靠性验证试验,使更新后的压力机控制系统实现了压力速度的快速调节,提高了液压系统运行可靠性。     

故障树在控制系统可靠性评估中的应用分析

针对典型的控制系统,采用故障树分析的方法对控制功能进行故障分析、故障树建模和计算。基于建立的故障树模型,对控制功能的可靠性进行评估和分析计算,获取控制系统各个组成部分的可靠性数值。利用计算得到的可靠性数据,提出对控制系统进行提高可靠性和降低可靠性优化改进的思路和方法,使优化后的控制系统具有适当的可靠性和良好的性价比。     

300MN模锻水压机同步平衡控制系统可靠性分析

对300MN模锻水压机同步平衡液压控制系统的可靠性进行了分析,根据系统的原理和功能,建立了系统的可靠性模型框图,进行了可靠性计算和系统的可靠性分析,为进一步提高同步平衡控制系统的可靠性提供了依据.     

基于WinCC的一万吨多向模锻水压机控制系统

利用SIMATIC S7-300PLC与IPC-610工业控制机相结合,组成两级计算机系统,用于一万吨多向模锻水压机控制系统,提高系统控制精度和工作可靠性。文中根据模锻水压机的生产工艺特点和控制要求,以WinCC V6为软件平台,设计开发上位机监控系统。重点阐述了分配器位置控制子系统的工作原理,给出了利用ANSI-C脚本实现一些功能的相关源代码。实际应用表明：该系统分配器位置控制精度高,系统功能齐全,人机界面友好,工作稳定可靠,各项控制功能均达到了设计要求。     

大型模锻水压机控制系统设计与实现

针对目前一些大型模锻水压机自动控制系统落后的现状,设计并开发了基于PLC S7-300的一万吨多向模锻水压机控制系统。详细介绍了控制系统的硬件配置和组成结构,分析了系统的工作原理,重点说明了分配器转角Fuzzy-PID复合控制子系统、自动生产子系统块和通信故障诊断子系统等软件模块的工作原理和流程框图。根据实际的调试和生产情况对系统进行了分析,分配器转角控制精度达到±1.5°,系统现场运行稳定,满足生产中对各种工艺参数的要求。     

GJB768.1——89附录A压力罐故障树的定量分析计算方法

本介绍了ＧＪＢ７６８．１－８９附录Ａ压力罐故障树的定量分析的一种方法，利用容斥定理或不交化法可以在诸底事件不可靠度已知的条件下，由结构函数来对压力罐控制系统进行可靠性定量分析。本同时也给出了由系统可靠性框图对系统可靠度的定量计算和分析方法。     

液压控制系统故障树分析

根据液压控制系统特点，建立系统故障树，提出了利用故障树的最小割集矩阵和计算结果重要度进行故障树定性分析的新方法。经工程实例验证表明，算法简单，通用可靠。     

300MN模锻水压机操纵系统改造方案研究

300MN模锻水压机原有操纵系统操作不便,控制精度低,响应速度慢,可靠性低。针对其机械本体特征及运行要求,改操作系统控制方式“水控水”为“油控水”方式,改操纵系统为数字电液伺服控制系统。新增加一油压系统,由操作手柄、按钮发出控制信号,通过PLC控制油压系统驱动执行油缸,实现分配器阀的正确动作;检测凸轮驱动机构的实际位置,反馈给控制系统,实现闭环控制,以实现对水压机的工作过程快速、精确、可靠控制。     

加工中心故障树分析

应用故障树分析法对加工中心故障的内在逻辑关系进行了分析,画出了整机故障树图,为采取可靠性增长提供了有效的信息。     

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...     

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。     

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。     

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.     

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.     

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。     

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...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

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.