含体积型缺陷油气输送管道剩余强度评价软件开发及应用

介绍一种依据SY/T 6477—2014标准开发的含体积型缺陷油气输送管道剩余强度评价软件,并以某均匀腐蚀管线钢管为例,运用该软件对其含缺陷剩余强度进行评价。该软件的核心计算模块由均匀腐蚀缺陷评价模块和局部腐蚀缺陷评价模块组成;可逻辑判断缺陷类型及量化方法,计算均厚长度、管道最大允许工作压力、许用剩余强度因子以及管道降压后最大允许工作压力。该软件具有计算结果准确、易操作、响应速度快的优点。     

弹塑性范围内含体积缺陷连续油管安全评价

含体积缺陷的连续油管在作业过程中可能发生卡断或拉断等事故,文章基于连续油管常见的缺陷形式,建立了含体积缺陷的连续油管模型,结合有限元基本理论,分析了塑性范围内的连续油管的剩余强度,以及不同载荷与缺陷尺寸特征对连续油管应力分布和极限承载能力的影响。分析结果表明:在塑性极限状态下连续油管的剩余强度要高于全弹性状态的剩余强度,连续油管的承载能力对缺陷深度和内压载荷表现的尤为敏感,随着缺陷深度的增加,承载能力变弱,并且在缺陷评价中应以压力载荷为标准。     

含平底型腐蚀缺陷钢管剩余强度的有限元求解和实验验证

以X65管线钢为研究对象,采用有限元方法（FEM）分析了不同深度和不同直径的平底型腐蚀缺陷对管线钢局部应力应变分布和剩余强度的影响规律,并通过实验方法进行了验证。结果表明,腐蚀缺陷深度愈大,剩余强度愈低;腐蚀缺陷直径愈大,剩余强度愈低,并且缺陷深度比缺陷直径对剩余强度的影响更为显著。采用拉伸实验方法,对直径为6 mm,深度分别为1/2壁厚和1/4壁厚的平底型腐蚀缺陷模拟试样进行实验验证,结果与FEM求解结果较为一致,尤其是含有大深度缺陷试样的实验结果同有限元计算结果的一致性更好。     

含多腐蚀缺陷油气管道的相互作用准则及剩余强度

利用ABAQUS软件,采用控制变量法和无量纲分析法,求解只含轴向或环向多腐蚀缺陷管道的等效应力,并提出了管道多腐蚀缺陷间的相互作用准则、判定流程和影响因素;在考虑腐蚀缺陷间相互作用效应的情况下,结合控制变量法,对处于复杂腐蚀状态下含多腐蚀缺陷的管道的剩余强度进行了数值模拟,并提出了剩余强度变化系数;采用正交试验设计法,分析了影响腐蚀管道剩余强度的主、次要因素。结果表明：当只有轴向或环向腐蚀缺陷时,轴向间距系数是影响管道应力状态的主要因素;当腐蚀轴向间距大于■时,腐蚀缺陷间无相互作用;当轴向、环向均有腐蚀缺陷时,腐蚀长度系数和腐蚀宽度系数是影响管道剩余强度的主要因素,腐蚀深度系数和轴向间距系数次之。     

喇嘛甸油田外输油管道完整性评价

本文针对大庆油田第六采油厂喇嘛甸油田外输油管道的缺陷检测和管体材料理化实验的结果，利用基于API579评价方法的管道缺陷剩余强度评价软件，进行管体剩余强度评价；建立了基于径向深度腐蚀速率的一维腐蚀寿命预测模型和基于轴向长度、环向宽度和径向深度腐蚀速率的三维腐蚀寿命预测模型，并对所检测的腐蚀剩余寿命进行了预测。     

含腐蚀缺陷管道安全评价准则选择探讨

外腐蚀是威胁管道安全的重要因素,极易导致管道泄漏或失效断裂事故。我国长输管道全面实施完整性管理,应根据管道历史失效事件,开展管道剩余强度评价与剩余寿命预测,确定不同类型缺陷的可接受准则。阐述了国际通用的管道缺陷安全评价标准,分别是ASME B31G、修正的ASMEB31G、BS7910、DNV-RP-F101和PCORRC准则。收集不同钢级(X42-X100)含腐蚀缺陷的管道规格、缺陷特征和失效压力数据,比选上述5项评价准则的准确性。管道管理者应根据管道运行状况和缺陷特征,考虑评价准则的优缺点和适用范围,选择合理、适用的评价准则。     

基于API579准则的含点腐蚀管道剩余强度分析

为了更加比较准确地评价含点腐蚀管道的剩余强度,从而科学合理地维护管道并提高管道的利用率,比较了几种评价点腐蚀管道的剩余强度的方法,得出API579的评价方法更适合用于点腐蚀缺陷管道评价的结论。以API准则为理论依据,对含有点腐蚀缺陷管道的剩余强度进行了3个等级的评价,并且通过计算得到了在给定的点腐蚀缺陷下管道最大安全运行压力值,该压力值反映了含点腐蚀缺陷管道的承压能力,证明了API579标准评价含点腐蚀缺陷管道的剩余强度的合理性。     

管道漏磁检测缺陷信号的仿真分析与量化模型

为实现漏磁检测缺陷几何尺寸的量化,运用有限元Ansys软件仿真了管道缺陷的二维缺陷漏磁场,给出了漏磁场缺陷信号的基本特征,并对图形做出对应的解释;其次对内外缺陷漏磁场信号进行了对比,提出了合适的两个特征值;最后根据漏磁场不同特征值与缺陷长度的变化规律对缺陷长度进行了量化,通过对比不同量化模型,给出缺陷信号特征值与缺陷长度的一般关系模型,为管道强度以及剩余寿命评价等提供相关的参数,从而对管道进行维护。     

腐蚀缺陷参数对油气管道剩余强度的影响

为了探索腐蚀缺陷对油气管道剩余强度的影响规律,将响应曲面法与ANSYS有限元法相结合,以在不同腐蚀参数缺陷下得到的油气管道剩余强度作为响应值,建立了腐蚀缺陷长度、宽度和深度与油气管道剩余强度响应输出之间的数学模型,讨论不同影响因素的显著性及其交互作用的影响规律。结果表明,单影响因素腐蚀缺陷深度对油气管道剩余强度影响最大,腐蚀缺陷长度与深度的交互作用比较显著。     

含缺陷管道极限压力的工程计算模型

含缺陷管道极限压力分析是管道结构完整性评定的重要内容之一,合理选择与发展含缺陷管道极限压力的计算方法对于评估管道剩余强度具有重要意义.综合介绍了几种类型含缺陷管道的极限压力的工程计算模型.     

Research Progress on Failure Analysis and Life Assessment of Key Components in Hydraulic SupportsEI北大核心CSCD

煤矿综采液压支架是控制采煤工作面矿山压力的大型核心装备,是现代采煤作业安全防护、作业空间扩大和采煤效率提高的关键,主要由液压件(立柱、千斤顶)、承载结构件(顶梁、掩护梁和底座等)、推移装置、控制系统和其他辅助装置组成,往往在极其恶劣复杂的矿井环境中服役,局部容易发生变形损伤、疲劳和腐蚀。对其关键部件进行失效分析及剩余寿命评估,是推动整机再制造和促进绿色循环经济发展的基本前提条件。对顶梁、底座、连杆、立柱等关键部件的失效形式及原因进行综述与分析,指出结构件的失效原因分析需要受到更多关注。总结支架寿命评估的研究现状,指出目前的研究集中在设计阶段的强度校核和寿命预估上,而关于服役了一段时间的支架的剩余寿命研究仍是空白。最后提出基于断裂力学利用有限元模拟进行剩余寿命评估的发展趋势。     

A computer system for tooth root optimization of case-hardened gearwheels

Today, shape optimization methods allow the minimization of the maximum stress occurring in the tooth root under load. For homogeneous material characteristics, as they are found in quenched and tempered steel, this is expected to result in similar increases in load carrying capacity. Highly loaded gearwheels are frequently case-hardened to achieve depth-dependent strength gradients, increasing from the core to the surface. Furthermore, load-reducing compressive residual stresses are induced within the surface layer. For case-hardened components, the reduction in maximum stress does not necessarily lead to an equivalent increase in load carrying capacity. In order to directly maximize the load carrying capacity of a gearwheel instead of minimizing the load stresses a computer system is developed which considers local strength as well as residual stresses.     

Evaluation of defects in aluminum piston castings by using ultrasonics and computer tomography

Pistons used in automobile engines are made of aluminum alloy; and endurance of high pressure and high temperature is required. Recently, high strength pistons are needed to cope with the increase of pressure and temperature in the engine cylinder. A high strength piston is possible when the piston casting has little or no casting defects, such as micro-pores and cracks. Generally the defects can be evaluated by non-destructive testing (NDT), and the most efficient ways for evaluation are using ultrasonics and computer tomography. In the present study, two NDT methods were compared and evaluated to investigate the defects in the aluminum piston castings. Artificial defects were machined by using very small drill bits with diameters 1, 0.5, 0.3, 0.2 and 0.1 mm. The defects were investigated by using an ultrasonic tester and a computer tomography system. Defects smaller than 0.3 mm may not be found by using the ultrasonic test, but the defects may be found by using the computer tomography system. The investigation conditions for detecting small defects and the scanning time for in-line defect analysis are discussed in the present study.     

Processing strategies for enhanced resistance to impact fracture of thin small-outline packages

The cracking potential of TSOPs (thin small-outline packages) was estimated under impact loading, similar to the process that triggers TSOP fracture during the mold ejection process of plastic-encapsulated microelectronic packaging. It was found that the susceptibility of TSOPs to impact-induced damage is more influenced by the existence of residual stresses than surface defects of the die, which result from the wafer back-lapping process. The experimental results showed that diamond particle-induced crater marks, which contribute to introducing residual stresses to particular sites of the die back surface, can be more critical for determining impact strength of TSOPs than grinding-induced scratch marks. The present work also showed that chemical tempering of the back surface of the die is very effective for suppressing such impact-induced damage of TSOPs under very low impact loads.     

内压对钢质套环液力胀接强度影响的研究

用弹塑性理论对液力胀接过程进行分析,得到不同变形阶段所需要的内压力及残余接触压力的计算公式。通过低碳钢管和中碳钢套环的液力胀接实验,对内压力对连接强度的影响进行研究。研究结果表明,套环完全屈服前,随着内压力和套环外壁残余应变的增大,连接强度也增大;对于存在屈服平台的套环材料,套环完全屈服后,连接强度保持不变;胀接后残余接触压力和扭矩计算公式可以为设计提供理论指导。     

Study on the effect of corrosion on the tensile behavior of an AZ91 alloy

The effect of corrosion on the tensile behavior of an as‐cast AZ91 alloy was investigated via systematical experiments. The corrosion residual strength of the AZ91 magnesium alloy is approximately negative linear dependent on the extreme depth of corrosion pit, which was quantitatively obtained by the corrosion morphology analysis and the statistic analysis. Experimental results reveal that the corrosion residual strength of the AZ91 magnesium alloy dropped quickly in the first 40 h due to the initiation and development of the corrosion pit and subsequently decreased slowly as a result of the development of the corrosion pit encountered the β phase. The β phase at the grain boundary of the primary α phase acts as an effective barrier to prevent the development of the corrosion pit into the alloy matrix and thus remarkably prevents the drop of the corrosion residual strength. In general, the variation of the corrosion residual strength exhibits an exponential decay regulation within the testing time. Consequently, the empirical prediction of the corrosion residual strength was given with regard to the variation of the corrosion residual strength varied with the immersion time.     

SEW高抗挤套管抗外压挤毁性能研究

研究了80~125钢级SEW高抗挤套管的材料性能、尺寸精度、残余应力和抗外压挤毁性能。研究结果表明:屈服强度是影响SEW高抗挤套管抗挤强度的决定性因素,径壁比、外径不圆度、壁厚不均度和残余应力是影响SEW高抗挤套管抗挤强度的主要因素;提高套管的屈服强度和尺寸精度,减小径壁比,降低残余应力均可提高套管的抗外压挤毁性能。     

含腐蚀缺陷X70钢剩余强度分析

采用ABAQUS有限元数值计算方法,分析了含腐蚀缺陷X70管道的剩余强度.根据相关标准的失效准则,研究了腐蚀的发展规律,并考虑到双腐蚀缺陷对管道剩余强度的影响.结果表明,对于双腐蚀缺陷,管道剩余强度随着两腐蚀轴向间距的增大而增大,最后趋于稳定;管道剩余强度随着两腐蚀缺陷径向夹角的增大而增大,最后趋于稳定.研究结果对于管...