输油管道补板焊接修复结构有限元分析

补板修复是一种常用的输油管道焊接修复技术,焊接过程中不可避免的会产生残余应力,在应力水平较大处,管道易发生失效。基于有限元法,采用顺序耦合的方法和随温度变化的材料参数,运用有限元分析软件MSC.Marc,以管道穿孔后补板修复为例,分析了补板焊接修复过程应力、温度场的分布情况和随时间的变化规律。结果表明:冷却后补板和补板周围的残余应力最大,残余应力主要由焊接热循环引起,管道内压对残余应力的影响很小。     

带压容器或管道泄漏的消除

化工生产中,带压容器或管道发生泄漏后,通常有两种焊补方法。一是停用容器或管道,放掉积液(或气)进行焊补,这种方法要求泄漏的容器或管道具有良好性能的前后进出口阀门,以使脱离生产系统,进行焊补,这些条件在实际生产中有时是很难办到的;另一种方法是带压焊补,这种方法无论是常压还是低压,只要焊补处有流体喷出,焊接就比较困难,非一般焊工都能胜任,更不用说压力再高一些了。为此,我们提供了一个简易有效的方法。首先,清除泄漏处表面的保温层或锈垢,露出金属光泽面,配上稍大的接管,接管的一头焊上一只法兰,並配有盲板(其工作压力应与泄漏容器或管道中的生产压力相一致),再将不带法兰的管端焊在泄漏区四周。要求接管与水平成一定的角度和有适当的长度。譬如,当泄漏出来的流体为液体或比重大于周围空气     

城镇燃气管道带压封堵局部应力分析

城镇燃气管道的安全运行是城镇居民安全用气的保障,针对城镇燃气管道泄漏带压封堵产生的局部应力问题,以补板修复方法为例,利用有限元分析软件ANSYS,分析内压、补板厚度和泄漏孔孔径等因素对孔结构受力的影响规律.结果表明:随着内压的增大,管道的边缘随之发生屈服,管道整体随内压呈正线性相关变化.当补口处的补板长度一定时,该位置处的补板厚度与局部应力成负相关,而与承载极限成正相关.对于开孔边缘,孔径的大小对其应力值影响最大,随着孔径的增大,其应力不断增大,直至屈服;同时孔径的大小对于孔板的交界处以及补板的内侧相对来说影响较小.     

不饱和聚酯树脂固化修复管道结构有限元分析及应用展望

基于北京地区某D1000钢筋混凝土污水管不饱和聚酯树脂紫外固化修复,采用SAP2000软件建立了不同树脂内衬管壁厚的分析模型,通过对组合结构内力对比及闭水试验结果,发现采用不饱和聚酯树脂固化修复破损混凝土管道,可有效提高管道整体结构强度,随着内衬管壁厚的逐步增加,被加固混凝土管道的内力水平逐步降低。其作为固化修复材料防渗效果功能性检验满足现行规范闭水试验的防渗要求。不饱和聚酯树脂可广泛应用于市政城市管道修复领域。     

低温压力容器接管口的焊接修复

对低温压力容器接管口修复中焊接存在的问题进行分析,分析了焊接缺陷产生的原因,通过对焊接工艺和热处理方法两个方面进行严格控制以避免焊接缺陷的产生,确保修复一次成功.     

输油管道漏油带压焊接技术探讨

随着油田工业化进程的不断加快,油品管道运输发展迅速,表现出明显的优越性,但石油管线腐蚀或打孔盗油等使管线损坏的事故越来越多,对损坏管道的修复已成为管道运输企业面临的重大课题。本文将对我国输油管道中的漏油在线带压焊接进行分析,并在此基础上提出一些建设性建议,以期为我国油田企业的发展提供一些参考。     

钨极氩弧焊在不锈钢薄皮管焊接中的应用

不锈钢薄皮管主要运用在食品、医药行业中。对于一般介质的管道焊接采用手工电弧焊焊接,使用之前进行压力试验,保证焊缝不漏即达到要求。对于不锈钢薄皮管的焊接则是采用手工钨极氩弧焊的方法进行,对这种特殊介质且管壁薄、直径小的管道,焊接要求是焊缝内部没有任何缺陷,施工难度也很大。本文分析了不锈钢薄皮管在现场组焊过程中的技术特点和质量控制要点,提出了相应的对策及检测方法。     

异种钢圆柱壳开孔接管的应力强度评定研究

重点考虑了开孔率和材料强度匹配对异种钢焊接结构的影响。按照GB 150-2011常规设计等面积补强方法确定接管壁厚,在此基础上,采用以JB 4732-1995弹性应力分析和理想弹塑性极限载荷方法为依据的有限元方法分别对其进行安全评定。结果表明,开孔率和材料强度匹配显著影响评定结果。对于有较低强度匹配和较大开孔率的圆柱壳径向接管结构,采用常规设计方法没有足够的安全裕量,采用分析设计方法可以保证结构的安全可靠。     

腐蚀管道非开挖修复中相关项管道强度评估和计算方法探讨

对腐蚀严重的污水管道进行非开挖修复具有诸多优势,在工程中得到了广泛的应用。腐蚀管道采用非开挖修复技术实施修复,涉及腐蚀管道剩余强度评估方法和计算方法、CIPP内衬管结构强度设计计算方法、复合管道强度计算方法。这几项管道强度的科学评估和计算,可为非开挖管道修复工程设计提供理论依据。     

油气管道雷达预警系统在中洛输油管道保护中的应用

为了最大限度降低油气管道因打孔盗油泄漏带来的严重后果,把雷达技术应用到埋地金属管道上,利用雷达技术实现油气管道在线监测,使油气管道在遭到破坏的初期及时发出预警,准确定位,从而降低因打孔盗油和油气管道发生泄漏造成的严重损失。重点介绍管道雷达预警系统的工作原理、特点,和目前使用的其他管道泄漏监测系统对比,以及油气管道雷达预警系统系统在中洛输油管道上的应用实例。     

复合材料增强修复油气管道的研究进展

回顾了近10年来利用复合材料增强或修复油气管道的最新研究进展,从增强未受损管道、修复含裂纹缺陷和体积缺陷管道方面对增强效果进行定性和定量的综述,探讨复合材料增强或修复油气管道中存在的问题和未来的研究方向.     

Mechanical behaviour of adhesively repaired pipes subject to internal pressure

Pipes can crack over time, particularly in areas with pipefittings and joints subject to high pressure and unsteady temperatures. Repair of these cracks requires labour, time, and expense and the cracked pipes are currently repaired with two methods. The first method is cutting out the damaged section of the pipe and adding an additional joint, which requires much time and labour. The second method is replacing the damaged pipe, which requires expensive materials. The aim of this study is to propose an alternative method that reduces or eliminates the use of labour, time, and materials, in order to quickly re-activate pipelines. For this purpose, the cracked steel pipes were repaired by using an adhesive, and the mechanical behaviours of the repaired pipes were investigated experimentally and numerically. In the first step of the study, artificial cracks were created on the pipes and the cracked pipes were repaired using adhesive and galvanized steel patches with different overlap lengths, overlap angles and thicknesses. Then, the repaired pipes were subjected to internal pressure in order to evaluate the effects of patch thickness, overlap angle and overlap length on the joint strength. Finally, the numerical analyses and experimental results show that the variation of the patch thickness, overlap length and overlap angle will change the stress distributions and strength of the adhesively repaired pipes.     

埋地硫酸管道的设计

介绍了架空管线、管沟敷设管线、管中套管敷设管线和直埋敷设管线等硫酸输送管线设计方案的优缺点。分析直接埋地硫酸管线设计的可行性,提出较详细的直接埋地硫酸管线设计方案及施工注意事项。对直接埋地硫酸管线出现的问题进行分析并提出整改意见。     

玻璃钢蜂窝夹层结构制品常见缺陷修补技术

主要研究低压成型玻璃钢及其蜂窝夹层结构制品中常见缺陷(板-芯脱胶,蒙皮分层)的修补技术。制备了SC-13基体/玻璃布低压成型玻璃钢蜂窝夹层结构制品中常见的板-芯脱胶与蒙皮分层2种缺陷试样,分别用树脂注射法和贴补法对缺陷进行修补,对3种试样(含缺陷试样、无缺陷试样和缺陷修补试样)进行了检测,测试了试样的弯曲强度,分析了修补方法和所用材料的合理性、修补技术的可行性。研究结果证实,采用铁锚204与无碱布-60制备的胶膜贴补修补板-芯脱胶、采用J-153低粘度环氧胶黏剂注射修补蒙皮分层均有效,且修补工艺方法简单,修补后剪切强度恢复率与弯曲强度恢复率均较高,达80%以上。     

Nonlinear stress analysis of v-notched aluminum plates repaired with the wet patch technique

In this study, V-notched aluminum plates were repaired using the wet patch technique. Two different repair operations, single-side and double-side composite patches, were applied to the notched plates. Four layers of woven carbon fiber textile and with the same reinforcement angle were used as a composite patch. Previously, the epoxy was saturated onto the prepared carbon fiber textiles and glued to the plates, and then those plates were placed in a vacuum medium. The repaired plates were experimentally tested under tension load. A nonlinear stress analysis was carried out using the finite element methodology in addition to the experimental results. As major foci of the study, the effects of repair type and notch size on failure behavior and plastic stress distribution were examined. As a result, it was found that the notch depth affects the repair performance far more than the notch width. Debonding failure load between the patch and the plate in plates repaired with a single-side patch was found to be two times higher than the yield load. For the double-side patch, the yield load was close to the debonding load and this repair method increases the debonding load more than a single-side patch.     

Design,testing and field deployment of a composite clamp for pipeline repairs

A novel method of repairing leaking or otherwise damaged metallic pipelines using composites is presented. The method uses a uniquely designed resin-infused composite clamp. This is a significant improvement over commercially available metal clamps, providing lightweight and corrosion-resistant benefits. The design, analyses and testing presented here show that these benefits are in addition to providing uncompromising strength and reliability to the repaired structure. The design includes a combination of calculations and design of experiment optimisation with Finite Element models. The developed design methodology is shown to be robust for designing different clamp sizes. Testing involved short- and long-term survival tests of the clamps as per industrial standards, as well as hot-wet conditioning followed by mechanical testing of the composite material. Finally, a case study field deployment of the clamp on a 4-in propane pipeline with internal corrosion is presented.     

玻璃纤维-铝合金层合板补强拉伸性能及破坏机理研究

对含预置孔缺陷的玻璃纤维-铝合金层合板修补前后进行了拉伸试验,讨论了拉伸过程中载荷随拉伸位移的变化趋势,并分析了补强片对于材料拉伸强度的影响及断裂破坏形式。结果表明,修补前后的玻璃纤维-铝合金层合板在拉伸过程中均经历了屈服阶段,修补后的层合板表现出了更明显的屈服现象,且载荷在破坏前出现了较大波动,孔直径为6 mm、10 mm、12 mm的缺陷试样在补强后的极限强度修复率分别为17.7%、13.2%、20.6%,补强片使层合板在拉伸破坏后在断裂位置呈现双扇形损伤,补强片的破坏为胶膜的剪切破坏,破坏界面位于铝合金表面。     

埋地输油管道检测、维修与评估的探讨

为了保证某公司所属12条埋地管道的安全运行,基于国内外通用的管道完整性管理理念,对12条埋地管线进行了有针对性的检测、维护与改造。首先进行管道腐蚀环境调查、阴极保护效果测试,基本掌握管道防腐层破损严重、阴极保护效果较差的管段,同时,对腐蚀防护系统保护效果较差的管段,开展有针对性的全面检验检测。在此基础上,对存在严重安全隐患的管段,采取防腐层修复与阴极保护改造措施以确保管道运行安全。实践证明,对在用的输油管道,采取必要的全面检验与针对性维护措施是确保管道安全运行的有效手段。     

带腐蚀缺陷采油管线剩余强度和剩余寿命的评价

为了评价某采油厂采油管道实际工况,基于ANSYS有限元法对管道腐蚀缺陷进行模拟,研究了不同缺陷类型下,缺陷长度、宽度、深度因素对管道失效的影响,分析了不同腐蚀类型缺陷对管道最大工作压力的影响。利用检测数据,对管道最大腐蚀速率进行了计算,并对管道剩余寿命进行了预测。结果表明:缺陷长度和深度是管道失效的直接影响因素,等效应力和工作压力成正比关系,管线的剩余寿命为10.2 a。此结果对管道的安全运行及维护具有重要的参考价值。