基于SolidWorks的不规则空间连接弯管设计

不规则空间连接弯管的应用非常广泛,但在工程的具体施工上存在着很大的难度及挑战。针对锅炉设备中复杂空间弯管不易设计的问题,提出了基于SOLIDWORKS的空间弯管设计方法,利用solidworks simulation结构有限元分析以及优化分析的应用方法对不规则空间连接弯管进行分析设计。实例证明,基于solidworks的不规则空间连接管道设计方法可靠,能广泛应用于弯管设计,有助于提高工程图的精度及设计效率。     

水下球形机器人推进器管道的设计和优化

根据水下球形机器人的设计需要,运用CFD(computational fluid dynamics)技术,对不同流态下不同截面尺寸和曲率半径的矩形截面弯管内的黏性流动进行了数值模拟.研究了离心力作用下二次流强度和壁面黏滞阻力随弯管参数变化的情况,得出了截面宽高比为0.75的弯管的水力损失最小的结论,并对该截面形状的弯管的流动结构进行了分析.最后,在标准试验平台上运用涡量探头对出口截面的涡流强度进行了测量,从而证明了数值模拟的正确性,并通过对比分析,完成了水下球形机器人的管道设计和优化.     

机械自适应管道机器人的机构原理与仿真分析

针对轮式管道机器人在遇到弯管或不规则管时会发生运动干涉的问题,提出将三轴差动轮系引入管道机器人驱动系统中,使轮式管道机器人具有对管道环境的自动适应性能,并对机械自适应管道机器人的机械结构进行了设计与研究．同时,对管道机器人进行了三维建模及运动仿真分析,验证了应用三轴差动轮系的管道机器人具有较强的弯管适应能力及管内运动的稳定性．该机器人具有适应能力强、结构紧凑、驱动效率高、工作可靠及成本低的特点．     

管道机器人三轴差动式驱动单元的设计研究

设计了由三轴差速机构、管径适应机构组成的管道机器人三轴差动式驱动单元,对驱动单元在直管、弯管的差速特性与力学特性进行了理论分析．三轴差动式驱动单元在直管中运动时差速机构不起作用;在弯管运动时,根据管道拓扑环境实现自主差速,且行走轮运动状态为纯滚动,无寄生功率产生．所设计的管道机器人三轴差动式驱动单元为机械自适应型差动式管道机器人的理论研究奠定了基础．     

耐腐蚀性油气储运管道内部应力流场模型仿真

油气储运管道的内部应力流场模型构建分析是刻画管道耐腐蚀性的重要指标。提出一种基于管道内流数值离散处理和黏性通量控制的耐腐蚀性油气储运管道内部应力流场模型构建方法,并进行数值仿真。根据低雷诺数湍流模型设计流湍流度多块结构化网格,求得载荷变化引起管道的内部流场规定的最小屈服强度,通过黏性通量控制,进行湍流动能生成曲率修正,实现油气管道内部应力流场模型构建。仿真结果表明,该模型能准确分析温度、压力对不同管径管道的变化规律,准确描述温度和压力变化对油气储运管道平均应力比率变化关系,实现对油气管道内部应力流场的定量分析,对提高管道设计的耐腐蚀性和耐高温高压性具有指导意义。     

数控弯管加工过程运动仿真系统的研究与开发

弯管是以管料作为毛坯,通过塑性加工手段,制造管料零件的加工技术.弯管具有产品轻量化、强韧化和低耗、高效等优点,是航空、航天以及民用工业中管道系统的重要组成部分.数控弯管是基于矢量弯管原理而发明的,数控弯管的应用大大提高了管件的加工效率和质量.数控弯管机、弯管模具按其加工管径的不同范围而成系列,对于不同规格的管件的加工须采用相应的弯管机及模具.     

三轴差速式管道机器人过弯管时的差速特性及拖动力分析

为解决轮式管道机器人通过弯管时的运动干涉和拖动力下降问题,减小由管道环境约束而引起的传动 件磨损,对一种具有机械自适应能力的轮式管道机器人驱动——三轴差速驱动——进行了深入分析和研究．通过对 三轴差速机构的受力分析,阐述三轴差速机构实现差速的受力原理;对三轴差速式管道机器人的差速特性及拖动力 进行研究,验证采用三轴差速机构的管道机器人具有良好的弯管通过性．     

管道弯制CAD/CAM系统的设计与实现

对管道弯制涉及的问题进行了分析,描述了管道弯制CAD/CAM系统整体框架,提出系统模块划分方案;给出了由管道XYZ坐标到YBC坐标的转换算法,结合管道回弹和延伸特性,建立了回弹延伸补偿算法,对弯管数据进行了修正补偿,并生成精确下料尺寸;根据工艺条件和碰撞因素,分别从可弯制性初步分析和仿真分析两个层次对管道的可弯制性进行了分析;利用Visual C 编程工具和OpenGL图形库对系统进行了实现.目前系统已成功投入运行.     

复合材料弯管曲面的整体造型设计

利用隐式几何造型方法的优点,建立了弯管过渡曲面的方程,改进了弯管现有的过渡方法,且保持其几何造型的特征,由于控制参数的调节作用,增加了过渡曲面造型的自由度.通过对弯管的应力分析得出:在圆环面与小圆柱面接合处、小圆柱面与过渡曲面的接合处、过渡曲面与大圆柱面的接合处这三处的应力突变都很小,表明该弯管的弯曲效应好,验证所建立...     

AutoCAD下蛇形弯管三维建模及展开

本文作者通过在AutoCAD中建立管道的三维模型,得到结构的相贯线,然后利用标注、查询等功能获取管道展开所需要的素线实长,进而进行管道展开图的绘制,利用该方法可以大大降低复杂管道(蛇形弯管)的加工维修难度.     

长输油气管线缺陷识别软件系统设计与实现

为了充分发挥金属磁记忆技术在管道缺陷检测中的优势,解决磁记忆信号本身不能判断缺陷类型的问题,建立了一种管道缺陷识别分类方法,设计并开发了一套基于C#和MATLAB混合编程的长输油气管线缺陷识别软件系统。该软件利用MATLAB对长输管线金属磁记忆数据进行数据处理、特征量计算及方法建模等工作,利用C#搭建面向用户的操作界面,使用户能够快速准确地对长输油气管道中的腐蚀缺陷、焊缝应力集中区域、弯管应力集中区域进行识别定位并加以区分。     

Effect of thickness variation on stress analysis of piping elbows under internal pressure

Finite elements and computer codes are being used extensively for the calculation of deflections, terminal reactions and stresses in piping and pressure vessels. In these practices, pipelines are usually idealised by straight or curved beams. In contrast to this, the theory for pipe bend is based on differential equations of shell theory and by using the flexibility factor concept, it is possible to introduce the effect of bends into a pipe system. It can be said that inaccuracies in bend flexibility factors and stress intensification factors can lead to erroneous results when the straight lengths to which they are attached to are short. Thin walled piping elbow's wall thickness are likely to vary as a result of manufacturing processes. With the increasing use of thin-wall pipe at high stresses the effect of the internal pressure becomes significant. In the present paper stresses in a piping elbow due to internal pressure are studied in the presence of thickness variation.A finite element scheme with a doubly curved shell element which can account for variation in thickness has been utilized in the present paper. The effect of wall thickness variation in a 90° bend taking into account the end constraint due to tangent pipe to which they are attached to on the stress distribution has been studied for varying pipe factors.In order to study how the stress intensification factor will differ with different arc lengths, bends of various included angles having non-uniform wall thickness have been analyzed.The material of the piping system is assumed to behave elastically.Numerical results show that the non-uniform thickness of the bend wall does not affect maximum stress factor even in the case of bends with pipe factors of the order 0.05. For 90° bends as pipe factor increases from 0.05 the maximum stress factor increases and then decreases as pipe factor approaches 0.15. For other included angle bends the stress factor varies linearly with a maximum value at low pipe factor. The maximum stress factor is found to vary linearly with bend angle for all pipe factors and thinning factor of the pipe wall.     

Finite element stress analysis of unilaterally supported submarine pipelines

A linear-elastic finite element model is applied to the solution of stress analysis problems involving submarine pipelines freely resting upon irregular seabed profiles. The structural matrix system is derived on an equal length element assembly basis, thus enabling the formulation of a particularly compact 3 d.f. nodal equation algorithm. The unknown contact points and the pipeline deformations are simultaneously identified with the aid of a successive over-relaxation solution algorithm. Tensions generated due to mean internal and external fluid pressure differences are taken into account. Surcharge imposition proves beneficial for the control of critical pipeline over-stressing and upward lift during pressurization. Case study details of the installation design for a subsea dual pipeline crossing are included. A FORTRAN subroutine is provided for illustration purposes of the proposed numerical technique.     

某车型发动机悬置后支架优化设计和疲劳分析

针对某车型发动机在振动强化试验中悬置后支架出现开裂的问题,建立悬置后支架有限元模型并进行应力分析,发现应力分析结果与试验结果一致,且原支架结构应力集中现象非常明显,主要分布在侧筋根部;用OptiStruct对悬置后支架进行拓扑优化设计,结果表明拓扑优化材料应主要布置在底部和侧筋.在此基础上,通过4种优化方案的对比得到质...     

An integrated planning tool for design of recycled water distribution networks

Pipeline design of urban recycled water networks involves thousands of decisions to ensure delivery of water to multiple use locations with pipelines and pump stations correctly located, optimally sized, and compatible with existing infrastructure. Here, we introduce PRODOT, Pipeline ROuting and Design Optimization Tool, software that identifies near-minimum-cost pipeline routes; accounts for existing configurations, legal, environmental or safety concerns, and trade-offs in pipeline length, pipe installation methods, traffic congestion during construction; optimizes pump station locations, pumping energy, pipe diameters and pressure classes; and includes theoretical additional capacity of each pipe, facilitating future expansion. We illustrate the utility of PRODOT with a case study for a local utility comparing PRODOT-generated configurations to a configuration proposed by an experienced consulting firm. The comparison shows that PRODOT produces pipeline configurations similar to the consulting firm's proposal with improvements by effectively and more broadly incorporating options the consultant may not have considered.     

Node-ranking schemes for the star networks

In this paper, three new node-ranking schemes for the star graph are presented and evaluated. These node-ranking schemes efficiently “embed” grids, pipelines, and reconfigurable multiple ring networks (cases of torus networks). These schemes improve similar known results on the star graph. They also allow efficient mapping of a wide class of algorithms into the star graph and hence facilitating further testing for the viability of the star graph as a potential interconnection network for large-scale multiprocessor systems. The proposed node-ranking schemes outperform their hypercube counterparts in terms of communication cost. Finally, two algorithms for solving systems of linear equations are given. These algorithms are based on the proposed grid and pipeline schemes to carry out matrix triangulation and backward substitution, respectively.     

基于CATIA/CAA的飞机燃油系统仿真软件研究

为提高飞机燃油系统管路设计效率,基于CAA二次开发技术以及CATIA管路模型几何与拓扑信息,开发具有3层架构的飞机燃油系统管路设计仿真软件. 该软件通过中间模型关联CAD和CAE软件,解决它们之间反复的数据传递和重复建模等问题;利用CATIA V5 Tubing Design工作台开发管流分析功能模块,实现飞机燃油系统管路建模时的在线流动分析.实例表明,该软件可提高燃油系统管路设计效率,具有实际应用价值.     

通用EPIC微处理器中指令控制流水线的研究与实现

指令控制流水线是在通用EPIC处理器内部专门为指令控制系统设计的一条与执行流水线相互锁步的流水线，用于携带共用信息和全局控制信息．提出了一种在通用EPIC微处理器设计中采用的指令控制流水线技术，介绍了指令控制流水线的具体设计与实现方法．实际应用表明，指令控制流水线技术能够有效降低EPIC微处理器的设计复杂度．     

大庆-铁岭输油管道SCADA系统

通过大庆-铁岭输油管道SCADA系统改造,介绍了该系统的设计原则,控制方案及特点。改造后的SCADA系统在可靠性、安全性及通讯传输等方面有较大的提高,为今后适应管线生产运行的变化和要求提供了可靠的软件和硬件的保障,为东北管网的综合管理提供了可靠的基础。     

基于数据共享的多级地下管线地理信息系统

针对当前管线系统存在重复建设、数据维护困难的问题,分析了基于数据共享的多级地下管线信息系统建设的必要性,提出了从专业管线信息系统中概括出综合管线的相关信息的思路,探讨了基于数据共享的多级地下管线信息系统的数据模型及其技术难点问题,设计并开发了基于ArcSDE的分布式管线系统,从而实现了两种管线系统的数据共享,有效避免了管线系统的重复建设。