Buckle propagation in pipelines with non-uniform thickness   总被引：1，自引：0，他引：1  

Jianghong  Michelle S.   《Ocean Engineering》2001,28(10)

Finite element solutions for the steady-state buckle propagation pressure in a pipeline with non-uniform thickness are given. The results are useful in finding buckle propagation pressures in corroded pipelines. It has been found that when corrosion is equal to or less than 10% of the original pipeline thickness, the pipeline collapses in an overall shell buckling mode; otherwise, the pipeline experiences local buckling. The propagation pressure decreases with both the thickness and angular extent of the reduced section, but the rate of decrease with thickness reduction is almost independent of the angular extent of corrosion when it is greater than 90°.  相似文献   

低合金钢在海水中腐蚀电化学行为的研究     

熊信勇  许川壁 《海洋科学》1991,15(3):53-56

本文采用微区电位扫描法,恒电流阶跃法、恒电位阶跃法等多种电化学方法,研究了两种在海水中抗腐蚀性能明显不同的低合金钢其腐蚀电化学行为的差异。结果表明,这种差异同低合金钢的抗腐蚀性能存在着一定的对应关系。  相似文献   

阴极保护时碳钢的交流阻抗特性和最佳防蚀电位   总被引：2，自引：0，他引：2       下载免费PDF全文

侯保荣  西方笃  水流徹  春山志郎 《海洋与湖沼》1993,24(3):272-278

测定了在3.5％食盐水中碳钢的法拉第交流阻抗,其结果与理论解析结果一致。阴极保护的实际效率(保护效率p和保护电流利用率q的乘积即r=p×q)在腐蚀电位E′_(cor)附近表现出最大值,这个电位可以认为是阴极保护的最佳保护电位。由于法拉第交流阻抗值容易被测得,为此提出了一种对阴极保护系统进行监测管理的一种新方法。  相似文献   

The Jiloca karst polje-tectonic graben (Iberian Range, NE Spain)     

F. J. Gracia  F. Gutirrez  M. Gutirrez 《Geomorphology》2003,52(3-4):215-231

The Jiloca depression, one of the largest morpho-structural units of the Iberian Range and traditionally considered as a neotectonic graben, is interpreted as a karst polje developed within an active halfgraben. This polje, 705 km² in area, constitutes one of the largest documented poljes. Several evidences—(1) a sequence of eight-stepped levels of corrosion surfaces, (2) the reduced thickness of the basin fill, (3) fault-controlled mountain fronts with topographic scarps much higher than the structural throws—demonstrate that great part of the topographic relief of the depression has been generated by corrosional lowering rather than by tectonic subsidence. The height difference between the highest corrosion surface and the polje bottom indicate that the depression has been deepened around 300 m by corrosion processes. The initiation of the karst polje was determined by the creation of the Jiloca halfgraben by normal faults, which deformed a Pliocene regional erosion surface. The development of the polje has been controlled largely by the asymmetric structure and the slight neotectonic activity of the graben. Changes in the position of the polje bottom inferred from the slopes of the different corrosion surfaces (polje paleotopography) may have been controlled by neotectonic movements.  相似文献   

The selection of corrosion prior distributions for risk based integrity modeling   总被引：1，自引：1，他引：0  

Premkumar Thodi  Faisal Khan  Mahmoud Haddara 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(6):793-809

The deterioration of the condition of process plants assets has a major negative impact on the safety of its operation. Risk based integrity modeling provides a methodology to quantify the risks posed by an aging asset. This provides a means for the protection of human life, financial investment and the environmental damage from the consequences of its failures. This methodology is based on modeling the uncertainty in material degradations using probability distributions, known as priors. Using Bayes theorem, one may improve the prior distribution to obtain a posterior distribution using actual inspection data. Although the choice of priors is often subjective, a rational consensus can be achieved by judgmental studies and analyzing the generic data from the same or similar installations. The first part of this paper presents a framework for a risk based integrity modeling. This includes a methodology to select the prior distributions for the various types of corrosion degradation mechanisms, namely, the uniform, localized and erosion corrosion. Several statistical tests were conducted based on the data extracted from the literature to check which of the prior distributions follows data the best. Once the underlying distribution has been confirmed, one can estimate the parameters of the distributions. In the second part, the selected priors are tested and validated using actual plant inspection data obtained from existing assets in operation. It is found that uniform corrosion can be best described using 3P-Weibull and 3P-Lognormal distributions. Localized corrosion can be best described using Type1 extreme value and 3P-Weibull, while erosion corrosion can best be described using the 3P-Weibull, Type1 extreme value, or 3P-Lognormal distributions.  相似文献   

高铝锌基合金（ZA）     

张兰英 《广东海洋大学学报》1995,(2)

高铝锌基合金是７０年代发展起来的一类新型合金。运用材料科学理论综合分析了国内外专家和研究人员在高铝锌基合金的组织、凝固特点与铸造性能、机械性能、耐蚀性能、热强性方面的研究现状．指出了存在的问题，提出了几点建议。  相似文献   

Les placers à silice ultrapure français : étude gîtologique comparative     

Laurent Désindes  Laurent Bailly  Jacques Leroy  Marc Lespinasse 《Comptes Rendus Geoscience》2005,337(9):832-840

The comparative study of two French high-purity silica placers of European class suitable for the electrometallurgy of silicon and ferrosilicon, located at Boudeau and Thédirac, in the Dordogne and Lot departments respectively, indicates strong similarities as regards the sources and the transportation of quartz, as well as a same process of undercover karstification as a determining factor in the formation of the deposits. The main difference lies in the number of the stages necessary to the formation of the trap. This comparative study allows the constitution of dynamic models for the genesis of these economic quartz concentrations. To cite this article: L. Désindes et al., C. R. Geoscience 337 (2005).  相似文献   

国外常用的检查井修复方法介绍     

周维  马保松 《岩土钻凿工程》2014,(2):104-108

在市政管道建设中,检查井主要作用是方便地下管线清淤、疏通以及修复等维护工作。检查井不仅承担路面车辆活荷载,还承担外部周围土体的土压力以及地下静水压力,井壁内部环境也十分复杂,长期受到废液和废气的腐蚀,十分容易出现破坏。针对这一情况,有必要对检查井及时地进行修复,防止其进一步恶化。保证检查井的密封性以及结构完整性。检查井的修复方法包括预制检查井更换,原位浇筑混凝土内衬,原位固化衬里,砂浆喷涂,黄麻纤维加聚氨酯树脂预聚物以及速凝水泥修复技术,各方法的设计施工特点以及适用范围有所不同。  相似文献   

反复荷载作用下锈蚀钢筋混凝土柱力学性能研究     

苏佶智  邢国华  马煜东  刘伯权 《震灾防御技术》2018,13(3):512-523

采用有限元软件ABAQUS,以锈蚀率（0%、5%、10%、15%和20%）为变量,对5根钢筋混凝土柱的力学性能进行了数值模拟,研究各试件的滞回性能、骨架曲线、延性及耗能能力,分析钢筋锈蚀率对承载力、延性、耗能和塑性铰转动能力的影响。研究结果表明:模拟分析得到的锈蚀钢筋混凝土柱的强度和变形与试验结果吻合较好,建立的有限元模型可用于锈蚀钢筋混凝土柱的力学性能分析;混凝土开裂前,锈蚀构件的力学性能基本与未锈蚀构件相同,混凝土开裂后,构件的承载力、屈服荷载、极限位移、延性等均随钢筋锈蚀率的增大而降低;轻度锈蚀构件的滞回性能和破坏形式与未锈蚀构件类似,随着钢筋锈蚀率逐渐增大,滞回环的饱满程度降低,“捏拢”现象严重,滞回曲线由“弓形”逐渐发展成“反S形”,耗能能力降低,破坏形式趋于脆性破坏,位移延性系数、平均耗能系数等指标逐渐下降。  相似文献