Finite elements in the analysis of pressure vessels and piping,an addendum: A bibliography (2001–2004)

The paper gives a bibliographical review of finite element methods(FEMs) applied for the analysis of pressure vessel structures/components and piping from the theoretical as well as practical points of view. This bibliography is a new addendum to the Finite elements in the analysis of pressure vessels and piping—a bibliography [1], [2], [3]. The listings at the end of the paper contain 856 references to papers and conference proceedings on the subject that were published in 2001–2004. These are classified in the following categories: linear and nonlinear, static and dynamic, stress and deflection analyses; stability problems; thermal problems; fracture mechanics problems; contact problems; fluid–structure interaction problems; manufacturing of pipes and tubes; welded pipes and pressure vessel components; development of special finite elements for pressure vessels and pipes; finite element software; and other topics.     

Finite elements in the analysis of pressure vessels and piping,an addendum: a bibliography (1998–2001)

The paper gives a bibliographical review of finite element methods (FEMs) applied for the analysis of pressure vessel structures/components and piping from the theoretical as well as practical points of view. This bibliography is an addendum to the Finite elements in the analysis of pressure vessels and piping—a bibliography (1976–1996) published [Int J Press Vess Piping 69 (1996) 279] and Finite elements in the analysis of pressure vessels and piping, an addendum (1996–1998) published [Int J Press Vess Piping 76 (1999) 461]. The new bibliography at the end of the paper contains approximately 670 references to papers and conference proceedings on the subject that were published in 1998–2001. These are classified in the following categories: linear and nonlinear, static and dynamic, stress and deflection analyses; stability problems; thermal problems; fracture mechanics problems; contact problems; fluid–structure interaction problems; manufacturing of pipes and tubes; welded pipes and pressure vessel components; development of special finite elements for pressure vessels and pipes; finite element software; and other topics.     

Finite elements in the analysis of pressure vessels and piping,an addendum (1996–1998)

The article gives a bibliographical review of the finite element methods (FEMs) applied for the analysis of pressure vessel structures/components and piping from the theoretical as well as practical points of view. This bibliography is an addendum to the Finite elements in the analysis of pressure vessels and piping-a bibliography (1976–1996) published in the Int. J. Press. Ves. Piping 1996;69:279–339. The added bibliography at the end of the article contains approx. 630 references to papers and conference proceedings on the subject that were published in 1996–1998. These are classified in the following categories: linear and non-linear, static and dynamic, stress and deflection analyses; stability problems; thermal problems; fracture mechanics problems; contact problems; fluid–structure interaction problems; manufacturing of pipes and tubes; welded pipes and pressure vessel components; development of special finite elements for pressure vessels and pipes; finite element software; and other topics.     

Moment resistance of steel pipes subjected to combined loads

The first part of this paper provides a review of recent investigations on steel pipes subjected to combined loads. Attention is given to studies involving both numerical and experimental components aimed at quantifying the modified moment resistance of pipes subjected to internal pressure and axial force. The comparison of experimental and finite element results indicate that the nonlinear shell finite element analysis is a reliable tool for predicting moment capacities of pipes. The second part of the paper reports two additional full-scale tests recently conducted at the University of Ottawa aimed at expanding the existing experimental database to pipes subjected to more complex load combinations involving twisting moment and shear (in addition to axial force, internal pressure, and bending). The finite element analysis for both tests is shown to provide excellent predictions of pipe moment capacity. The third part of the paper is a systematic parametric study based on the FEA model verified in previous and present investigations, aimed to assess the ability of pipe sections to attain their modified elastic and/or plastic moment resistance as predicted by analytically derived interaction equations. The parameters investigated are the applied torsion, internal pressure, axial force, and the diameter-to-thickness ratio of the pipe.     

Local and global flexibility of nozzle-to-vessel-intersections under local loads as boundary conditions for piping system design

In practical applications, process equipment in plants is exposed to local loads from a piping system. In most cases the reaction of the intersection of socket and vessel is unknown. This problem makes the analysis of a piping system difficult, because the flexibility of reactors changes the boundary conditions; this paper presents a study to overcome such problems. Knowledge about the boundary conditions is of considerable importance for the design of processing equipment and piping in plants. Elastic finite element analyses in combination with experimental investigations are performed for the purpose of solving such a problem.     

薄壁疲劳容器大开孔有限元分析

由于薄壁大开孔压力容器在开孔接管部位有很大的应力集中,必须进行补强,针对薄壁疲劳容器大开孔问题,采用有限元法得到了大开孔设备在危险工况载荷下的应力和变形,提出了可行的开孔区域加强措施,并提出两种解决方案,用有限元分析的方法进行对比分析。     

Load capacity of a thick-walled cylinder with a radial hole

The paper deals with elastic–plastic analysis of the stress–strain state in the vicinity of a hole in a thick-walled cylindrical pressure vessel. The investigations have been inspired by the phenomenon of ductile fracture observed in a high-pressure reactor. Using finite element calculations, different failure criteria are proposed to aid design and control of high-pressure vessels with piping attachments. They are compared with suggestions of American (ASME) and European (EN) standards. A simple shakedown analysis of the structure is also presented.     

Simplified fitness-for-service assessment of pressure vessels and piping systems containing thermal hot spots and corrosion damage

Fitness-for-service (FFS) assessment is a quantitative engineering evaluation of operational components. In the context of pressure vessels and piping systems FFS assessment is performed periodically to ensure the operational safety and structural integrity. In this paper, a simplified method is developed for Level 2 FFS assessment (as described in API 579) of pressure vessels and piping systems containing thermal hot spots or corrosion damage. The method is based upon variational principles in plasticity, the m_α-tangent method (an extension of the m_α method), the concept of decay length and reference volume. The use of the m_α-tangent method extends the range of applicability to components and structures experiencing significant stress gradients in and around the damaged spot. The method is shown to provide a reasonably accurate estimate of the remaining strength of ageing pressure components. The method is demonstrated through an example, and the results are compared with Level 3 inelastic finite element analyses.     

Ultrasonic testing technique for small-calibre piping containing defects

An effective method of ultrasonic testing was developed for inspecting the quality of weld seams for small-calibre, thin-walled pipes. The basic technical problems encountered in measuring the height of defects in the piping by an ultrasonic testing method were analyzed and studied experimentally. To overcome these problems, two small probes with special cylindrical contact surfaces, and five types of piping contrast specimens were machined, and a corresponding quantitative scaling method was developed. Some preliminary data obtained by the proposed method and a practical measurement method were presented. These results show that the proposed method is also effective in determining the shape of defects in welded steel pipes, and has been directly used in the structural integrity assessment of pressure vessels and piping containing weld defects in a petrochemicals plant.     

高压立式储罐的设计

本文主要介绍在设计温度(50℃)、高压(32MPa)、操作介质是混合气体条件下高压储罐的设计方法。并采用有限元对局部结构进行分析验证。本文对同类设备设计具有一定的参考价值。     

The interaction of pressure, in-plane moment and torque loadings on piping elbows

This study concerns the load interaction behaviour of 90° smooth piping elbows with circular cross-section and long straight tangent pipes. The finite element method is used for stress analysis of elbows having a wide range of bend and pipe factors. The main aim of the study is to establish the first yield interaction behaviour when an elbow is subjected to a combination loading of in-plane bending, torsion and internal pressure. The study shows that load interaction is influenced by pipe factor, bend radius and load coupling effect, with thinner elbows being affected to a larger degree.     

核电站高中能管道断管影响探讨

在设计核电站时,须对安全壳内外的高能与中能管道进行发生假想性断管事件及其后续效应的设计分析。这些管道一旦发生破裂,泄漏的高能量流体将对管道施加很大的横向力,使管道产生高速运动,即管道甩动。这种高速运动的管道可能会对周围结构造成严重破坏,因而引起世界上各主要发展核电国家的重视,并开展了大量的研究工作。详细叙述常规岛侧高中能管道断管位置的判定准则、假想破口的类型、断管的后续影响及其防护等。还进一步介绍有关管道断裂甩动问题的各种计算方法,如力矩平衡法、能量平衡法、有限元法等。     

Plastic limit pressures for cracked pipes using finite element limit analyses

Based on detailed finite element (FE) limit analyses, the present paper provides approximations for plastic limit pressure solutions for plane strain pipes with extended inner axial cracks; axi-symmetric (inner) circumferential cracks; axial through-wall cracks; axial (inner) surface cracks; circumferential through-wall cracks; and circumferential (inner) surface cracks. In particular, for surface crack problems, the effect of the crack shape, semi-elliptical or rectangular, on the limit pressure is quantified. Comparisons with existing analytical and empirical solutions show a large discrepancy for short circumferential through-wall cracks and for surface cracks (both axial and circumferential). Being based on detailed 3D FE limit analysis, the present solutions are believed to be accurate, and thus to be valuable information not only for plastic collapse analysis of pressurised piping but also for estimating non-linear fracture mechanics parameters based on the reference stress approach.     

A comparative study of usefulness for pad reinforcement in cylindrical vessels under external load on nozzle

The main purpose of this paper is to perform a comparative study of strength behavior for cylindrical shell intersections with and without pad reinforcement under out-of-plane moment loading on nozzle. Three pairs of full-scale test vessels with different d/D ratios were designed and fabricated for testing and analysis. A three-dimensional nonlinear finite element numerical analysis was also performed. The maximum elastic stress for each vessel under per unit moment on nozzle is provided. The plastic limit moment on nozzle is obtained by load–displacement and load–strain curves for each test vessel. The results indicate that the effect of pad reinforcement on decreasing maximum elastic stress and increasing plastic limit load is obviously effective. The study results will serve as the available data for understanding the usefulness of pad reinforcements and as the basis for developing an advanced design method by limit analysis for pad-reinforced cylindrical vessels under external loads on nozzle.     

Stress corrosion cracking of nuclear reactor pressure vessel and piping steels

This paper presents an extensive investigation of stress corrosion cracking of nuclear reactor pressure vessel and piping steels exposed to hot water. Experimental fracture mechanics results are compared with data from the literature and other laboratories. Thus a comprehensive overview of the present knowledge concerning stress corrosion crack growth rates is provided. Several sets of data confirm that ‘fast’ stress corrosion cracks with growth rates between 10⁻⁸ and 10⁻⁷ m/s and threshold stress intensities around 20 MN m^−3/2 can occur under certain conditions. However, it appears possible that specific environmental, mechanical and metallurgical conditions which may prevail in reactors can result in significantly lower stress corrosion crack growth rates. The presently known stress corrosion crack growth rate versus stress intensity curves are discussed with emphasis on their usefulness in establishing safety margins against stress corrosion cracking of components in service. Further substantial research efforts would be helpful to provide a data base which permits well founded predictions as to how stress corrosion cracking in pressure vessels and piping can be reliably excluded or tolerated. It is emphasized, however, that the nucleation of stress corrosion cracks (as opposed to their growth) is difficult and may contribute substantially to the stress corrosion free service behavior of the overwhelming majority of pressure vessels and pipes.     

Creep damage prediction of the steam pipelines with high temperature and high pressure

Creep is the significant factor that caused failure of steam pipelines with high temperature and high pressure in the period of long-term service. In this paper, the creep tests were performed at serviced temperature of 520 °C for 1.25Cr–0.5Mo pipe material, and the creep and fracture constants were obtained by fitting the creep test data. Based on the modified Karchanov–Rabotnov constitutive equation, compiled the user subroutine computing the damage of the pipe element or 3D solid element, the creep damage prediction was carried out by finite element methods using ABAQUS codes for the steam pipelines with high temperature and high pressure, which serviced in a petro-chemical plant, the damage distribution and maximum damage location of the pipelines were obtained, which is testified by metallographic examination result. Furthermore, the local creep damage analysis of a tapered pipe serviced for 100,000 h was also carried out because tapered pipes used in the main steam pipeline is one of weakness in the piping system. Damage distribution and evolution in the analyzed tapered pipe were obtained. The location with the maximum damage value was determined, which is coincident with cracking position of the actual tapered pipe.     

堤基管涌侵蚀破坏过程的无单元法模拟

针对堤基管涌侵蚀破坏过程的复杂渗流场模拟问题,采用无单元Galerkin法数值模拟研究管涌动态发展过程及机理,介绍了管涌区域破坏的判别方法、管涌尖端附近节点加密方法等,并结合砂槽模型试验和有限元模拟结果对无单元法的计算结果进行了验证与分析。结果表明,采用无单元法计算得到的管涌渗流场和有限元计算结果基本吻合,且管涌发展过程和模型试验结论较为一致;获得了管涌侵蚀破坏过程中管涌通道尖端水平渗透比降的变化规律,弥补了砂槽模型试验的不足。     

Modeling and simulation of a composite high-pressure vessel made of sustainable and renewable alternative fibers

To substitute the standard carbon fiber reinforced epoxy composite, sustainable and renewable alternative fibers are investigated for the use of high-pressure vessel through a finite element model. The standard T700S carbon fiber pressure vessel exhibits a minimum burst pressure of 1483 bar on the first layer oriented at 90°. The burst occurs in the central part showing a safe burst and the radial deformation reaches 1.12 mm. Several alternative fibers (basalt, E-glass, flax and recycled T700S carbon) are compared to the T700S carbon fiber. It results of lower burst pressures and none of the alternative composites caters for the minimum pressure threshold of 1400 bar. According to the storage pressure and in respect of the mechanical requirements, hybrid vessels integrating alternative and T700S carbon fibers are proposed to improve physical, environmental and economic performances. From an economic point of view, the optimal vessels are the E-glass/T700S carbon hybrid vessel and E-glass vessel for 700 and 350 bar, respectively. Regarding the environmental impact, the most suitable fibers are basalt/T700S carbon for a 700-bar storage and E-glass for 350 bar. Concerning the vessel mass, T700S carbon composite stays obviously the best candidate for a 700-bar storage but at 350 bar T700S carbon/flax fibers composite appears to be more efficient.     

基于自主有限元软件的反应堆压力容器密封分析

  [目的]  反应堆压力容器的密封性是保证核电站安全运行的关键因素之一,因此对其密封进行系统深入地研究具有重要的工程意义。自主开发的结构有限元软件ATLAS根据结构有限元分析的应用特点,在创新的预排序文件缓存技术和三维渲染技术等方面做了大量的优化工作,能让CAE工程师在高度交互及可视化的环境下进行仿真分析工作。  [方法]  利用ATLAS软件建立压力容器模型,对压力容器螺栓预紧力、密封法兰的接触过程进行了数值模拟,得到了其受力特性和应力分布规律。  [结果]  研究表明:ATLAS可以准确的导入模型,划分网格,施加各种工况,快速完成求解计算,很好的完成密封问题的有限元分析。计算结果的准确性能够得到保证,可以使用该方法进行压力容器的密封分析和应力校核。  [结论]  ATLAS是一个适用于核电工程的大规模结构快速有限元分析系统,可以用来进行压力容器的接触分析和结构强度的校核,具有较好的应用前景。     

大溪水库溢洪闸静动力三维有限元分析

主要介绍了应用大型通用有限元软件对大溪水库溢洪闸进行三维有限元静、动力分析的方法,采用更为合理的接触分析模型模拟侧向土压力作用下闸室底板与基岩的张开效应,研究探讨了闸室结构在各种工况下的变形及应力分布规律,进而了解闸室结构在设计条件下的工作形态,评价结构的安全性能,并根据三维有限元静动力分析成果优化了闸室的结构设计,使结构布置更为合理,在实际工程中取得了良好的效果。