Limit Loads of Bolted Flange Connections

2021 ◽  
Author(s):  
Finn Kirkemo ◽  
Przemyslaw Lutkiewicz

Abstract High-pressure applications such as process piping, pressure vessels, risers, pipelines, and subsea production systems use bolted flange connections. Design of flanged joints may be done by design by rules and design by analysis. This paper presents a design by rules method applicable for flanges designed for face-to-face make-up. Limit loads are used to calculate the structural capacity (resistance) of the flanges, bolts, and metallic seal rings. Designers can use the calculation method to size bolted flange connections and calculate the structural capacity of existing bolted flange connections. Finite element analyses have been performed to verify the analytically based calculation method. The intention is to prepare for an ASME code case based on the calculation method presented in this paper.

1997 ◽  
Vol 119 (2) ◽  
pp. 161-166
Author(s):  
J. S. Porowski ◽  
W. J. O’Donnell ◽  
R. H. Reid

Within the last two decades, the use of elastic finite element analyses to demonstrate design compliance with the rules of the ASME Code has become a generally accepted engineering practice. Linearized stresses from these analyses are commonly used to evaluate primary stresses. For redundant structures or complex structural details, the use of such analyses, instead of simple equilibrium models, often results in significant overconservatism. Direct use of finite element results is often preferred because equilibrium solutions are not unique and effective equilibrium models are not easily constructed for complex three-dimensional structures. However, finite element analyses include secondary stresses, even for pressure, mechanical, and shock loading. For primary stress evaluation, the ASME Code allows the use of inelastic methods based on lower-bound solutions and plastic analysis. For primary stresses, the Code requires equilibrium to be satisfied without violating the yield strength of the material. The use of finite element inelastic analysis to partition mechanically induced stresses into the primary and secondary categories was introduced by Porowski et al. (1993). The latter provides a detailed discussion of the technical approach and the results for the axisymmetric junction between the plate and shell in a pressure vessel. This example was selected by the Session Organizer as a benchmark case to compare the efficiency of various analytical approaches presented at the Session. The authors have since used this approach to design more efficient structures. The practical application of this method to reduce the weight of complex redundant structures designed to meet primary stress limits is described herein for a more complex three-dimensional case. Plastic design utilizes the ability of actual materials to find the most efficient load distribution. A heat exchanger subjected to pressure, accelerations, and nozzle external loads is evaluated as a practical example. The results of elastic analyses are compared with those obtained by inelastic analyses. It is shown that inelastic analyses can be used effectively to reduce the weight of structures using only modern PCs for the engineering computations, as illustrated in this paper.


Author(s):  
Abdel-Hakim Bouzid ◽  
Ali K. Vafadar ◽  
Anh-Dung Ngo

Abstract Fiber Reinforced Plastic composite flanges have recently experienced a spectacular development in the area of pressure vessels and piping. The current procedures used for the design of these flanges are a major concern because of their inappropriateness to address the anisotropic behavior of composite materials. The current ASME code section X related to the design procedure of composite flanges uses the same analytical method as the one of section VIII division 2 which treat the flanges as isotropic materials such as metallic flanges. This study deals with FRP bolted flange joints integrity and bolt tightness. A new developed analytical FRP model that treats anisotropic flanges with and without a hub is presented. The model is based on the anisotropy and a flexibility analysis of all joint elements including the gasket, bolts and flanges. It is supported experimentally with tests conducted on a real NPS 3 class 150 WN FRP bolted flange. Furthermore, three different numerical models based on 3D anisotropic layered shell and solid element models were conducted to further compare and verify the results obtained from the new developed analytical approach. The results show that the new model has potential to be used as an alternative tool to FEM if an accurate method to analyses the stresses and deformation of problematic FRP bolted joint applications.


Author(s):  
M. Schaaf ◽  
J. Bartonicek

In Europe, in 2001 the new standard EN 1591 for strength and tightness proofs of bolted flange connections (BFC) of floating type flanges was released. In addition, the German nuclear code was revised regarding the calculation of BFC. With this standard not only the floating type but also the metal-to-metal contact type of flanges (MMC) can be treated. Additionally, the ASME code is the basis for the flange calculation in the European standard EN 13445, which is the standard for unfired pressure vessels. In compliance with the goal of the calculation, the different calculation codes can be used. There must be a differentiation between the design of the components, the determination of the prestress values for assembly, the stress analysis and the tightness proof of the BFC. First, all parameters which influence the function of the bolted flange connection are considered. In a second step, the range of use of the different standards and the calculation algorithm are discussed.


Author(s):  
Finn Kirkemo

Flanged joints are used in high pressure applications such as process piping, pressure vessels, risers, pipelines and subsea production systems. These flanges are subjected to external loads in addition to pressure. A brief description of high pressure flanges standards is given. Design of high pressure flanged joints are covered in many design codes. A review of allowable stresses, load factors for bolting, flanges and bolt preload requirements has been made for the following codes: ASME VIII-2, ASME VIII-3, ASME B31.3 Chapter IX, API 6A, API 6X, API 17D, API 17TR7, API 17TR8, API 17G, EN 1591-1 and NORSOK U-001. This paper also presents analytically based structural load-capacity (ultimate strength) design equations for flanged joints. The design equations are used to calculate rated working pressure and flange-face separation load-capacity of API 6A type 6BX flanges. Future code recommendations for flange design are provided.


Author(s):  
Ali Khazraiyan Vafadar ◽  
Abdel-Hakim Bouzid ◽  
Anh Dung Ngô

Abstract Fiber Reinforce Plastic composite flanges have recently experienced a spectacular development in the area of pressure vessels and piping. The current procedures used for the design of these flanges are a major concern because of their inappropriateness to address the anisotropic behavior of composite materials. The current ASME code design procedure of composite flanges of section X uses the same analytical method as the one of section VIII division 2 which treat the flanges as isotropic materials such as metallic flanges. This study deals with FRP bolted flange joints integrity and bolt tightness. A new developed analytical FRP model that treats anisotropic flanges with and without a hub is presented. The model is based on the anisotropy and a flexibility analysis of all joint elements including the gasket, bolts and flanges. It is supported experimentally with tests conducted on a real NPS 3 class 150 FRP bolted flange. Furthermore, three different numerical models based on 3D anisotropic layered shell and solid element models were conducted to further compare and verify the results obtained from the new developed analytical approach. The results show that the new model has potential to be used as an alternative tool to FEM if an accurate method to analyses the stresses and deformation of problematic FRP bolted joint applications.


2009 ◽  
Vol 131 (3) ◽  
Author(s):  
R. D. Dixon ◽  
E. H. Perez

The available design formulas for flat heads and blind end closures in the ASME Code, Section VIII, Divisions 1 and 2 are based on bending theory and do not apply to the design of thick flat heads used in the design of high pressure vessels. This paper presents new design formulas for thickness requirements and determination of peak stresses and stress distributions for fatigue and fracture mechanics analyses in thick blind ends. The use of these proposed design formulas provide a more accurate determination of the required thickness and fatigue life of blind ends. The proposed design formulas are given in terms of the yield strength of the material and address the fatigue strength at the location of the maximum stress concentration factor. Introduction of these new formulas in a nonmandatory appendix of Section VIII, Division 3 is recommended after committee approval.


2021 ◽  
Vol 43 ◽  
pp. e55825
Author(s):  
Roberto Outa ◽  
Fábio Roberto Chavarette ◽  
Aparecido Carlos Gonçalves ◽  
Sidney Leal da Silva ◽  
Vishnu Narayan Mishra ◽  
...  

The motivation for the development of this work arose from the observation of maintenance in pressure vessels, which are categorized as highly hazardous security risk products. The costs of detecting failures in the production systems allow the result of the process to be safe and of good quality, using standardized tests internally within the company. The main objective of this work demonstrates the efficiency and robustness of the artificial immune system (AIS) of negative selection in the detection of failures by recognizing the vibration signals and categorizing them in the degree of probability and level of severity of failures. The intrinsic objectives are the application of the elimination of signal noise by the Wiener filter, and the processing of data-Wiener data using experimental statistics. The result of this work successfully demonstrates the precision between the experimental statistical and AIS techniques of negative selection; the robustness of the algorithm in precision and signal recognition; and the classification of the degree of severity and probability of failure


2021 ◽  
pp. 565-637
Author(s):  
Luis A. Ganhao ◽  
Jorge J. Perdomo ◽  
James McVay ◽  
Antonio Seijas

Abstract This article discusses pressure vessels, piping, and associated pressure-boundary items of the types used in nuclear and conventional power plants, refineries, and chemical-processing plants. It begins by explaining the necessity of conducting a failure analysis, followed by the objectives of a failure analysis. Then, the article discusses the processes involved in failure analysis, including codes and standards. Next, fabrication flaws that can develop into failures of in-service pressure vessels and piping are covered. This is followed by sections discussing in-service mechanical and metallurgical failures, environment-assisted cracking failures, and other damage mechanisms that induce cracking failures. Finally, the article provides information on inspection practices.


2020 ◽  
Vol 32 (4) ◽  
pp. 573-591
Author(s):  
Micael Queiroga dos Santos ◽  
Xosé A. Rodríguez ◽  
Ana Marta-Costa

Purpose The purpose of this paper is to estimate and analyse the technical efficiency (TE) component of productivity for a sample of winegrowers from the Douro Demarcated Region in Portugal. Design/methodology/approach The data were collected through face-to-face surveys and includes a sample of 110 farmers’ vineyards with specific input-output information and other data about production systems during the year of 2017. The authors use a two-stage data envelopment analysis using bootstrap techniques to obtain TE scores in the farmers’ vineyards and to examine the determinants of its efficiency. Findings The results show that some farmers’ vineyards have a low efficiency level and that there are essential determinants of the production system, which can influence its efficiency. This suggests considerable opportunities for improvement of wine grape productivity through better use of available resources considering the state of technology. Originality/value This work has overcome the lack of data in the farmers’ vineyards, the lack of efficiency studies in the region and also allowed to evaluate the production systems and to assess their impact on efficiency.


2011 ◽  
Vol 308-310 ◽  
pp. 1571-1576 ◽  
Author(s):  
Xiu Feng ◽  
Feng Lu ◽  
Guo Liang Shen

Metallic gasket seals are widely used in pressure vessels and piping. The failure of sealing systems is mostly caused not by the strength of flanges or bolts but by the leakage of the connections. The contact area of sealing surface has a major influence on the leakage of the bolted flange connections. The contact model of sealing surfaces of the flange and the metallic gasket was established on the basis of the modified M-B model, and the relationship between the contact area and the compressive stress is obtained. It’s found that the bigger the compressive stress, the bigger the contact area. When the compressive stresses are identical, the bigger fractal dimension and the less scale coefficient, the bigger the contact area. These can be used in the evaluation of sealing behavior of metallic gaskets.


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