Analysis of Half-Pipe Heating Channels on Pressure Vessel Shells

1986 ◽  
Vol 108 (4) ◽  
pp. 526-529
Author(s):  
A. E. Blach

Half-pipe heating channels are used on the outside of pressure vessels such as agitators, mixers, reactors, etc., to avoid the high external pressure associated with heating jackets. No applicable method of analysis is contained in the ASME Code and proof tests are normally required for registration with governing authorities. An analytical method is presented which permits the evaluation of stresses in shell and half pipe; numerical examples are included.

Author(s):  
Kanhaiya L. Bardia ◽  
Kim Nguyen ◽  
Manfred Lengsfeld ◽  
Donald G. LaBounty ◽  
Bernie Au

Code Case 2286-1 [1] of the ASME Boiler and Pressure Vessel Code [2][3] provides alternate rules for determining the allowable external pressure and compressive stresses for cylinders, cones, spheres, and formed heads in lieu of the rules of Section VIII, Divisions 1 and 2. The authors in this paper present a comparison of the longitudinal and circumferential compressive stresses in pressure vessels based on the methods outlined in Paragraph UG-28 of Division 1, Section VIII of the ASME Code and Code Case 2286-1. The Do/t ratio in this paper is limited to 600 which covers the majority of pressure vessel designs found in the petrochemical industry. A sample vessel shell design is presented applying both the ASME Code, Section VIII, Div. 1 method and that of Code Case 2286-1.


Author(s):  
K. K. Yoon ◽  
J. B. Hall

The ASME Boiler and Pressure Vessel Code provides fracture toughness curves of ferritic pressure vessel steels that are indexed by a reference temperature for nil ductility transition (RTNDT). The ASME Code also prescribes how to determine RTNDT. The B&W Owners Group has reactor pressure vessels that were fabricated by Babcock & Wilcox using Linde 80 flux. These vessels have welds called Linde 80 welds. The RTNDT values of the Linde 80 welds are of great interest to the B&W Owners Group. These RTNDT values are used in compliance of the NRC regulations regarding the PTS screening criteria and plant pressure-temperature limits for operation of nuclear power plants. A generic RTNDT value for the Linde 80 welds as a group was established by the NRC, using an average of more than 70 RTNDT values. Emergence of the Master Curve method enabled the industry to revisit the validity issue surrounding RTNDT determination methods. T0 indicates that the dropweight test based TNDT is a better index than Charpy transition temperature based index, at least for the RTNDT of unirradiated Linde 80 welds. An alternative generic RTNDT is presented in this paper using the T0 data obtained by fracture toughness tests in the brittle-to-ductile transition temperature range, in accordance with the ASTM E1921 standard.


Author(s):  
S. R. Gosselin ◽  
F. A. Simonen

Probabilistic fracture mechanics studies have addressed reactor pressure vessels that have high levels of material embrittlement. These calculations have used flaw size and density distributions determined from precise and optimized laboratory measurements made and validated with destructive methods as well as from physical models and expert elicitation. The experimental data were obtained from reactor vessel material samples removed from cancelled plants (Shoreham and the Pressure Vessel Research Users Facility (PVRUF)). Consequently, utilities may need to compare the numbers and sizes of reactor pressure vessel flaws identified by the plant’s inservice inspection program to the numbers and sizes of flaws assumed in prior failure probability calculations. This paper describes a method to determine whether the flaws in a particular reactor pressure vessel are consistent with the assumptions regarding the number and sizes of flaws used in other analyses. The approach recognizes that ASME Code Section XI examinations suffer from limitations in terms of sizing errors for very small flaws. Direct comparisons of a vessel specific flaw distribution with other documented flaw distributions would lead to pessimistic conclusions. This paper provides a method for a valid comparison that accounts for flaw sizing errors present in ASME Code Section XI examinations.


Author(s):  
Yoichi Ishizaki ◽  
Futoshi Yonekawa ◽  
Takeaki Yumoto ◽  
Teppei Suzuki ◽  
Shuji Hijikawa

As widely recognized in the industry, it is important to evaluate the creep damage of an elevated temperature vessel so that the mechanical integrity of the vessel can be achieved through the adequate repair and replacement planning. This is quite straight forward procedure for internal pressure vessels. For an external pressure vessel, it is not easy to assess the creep damage due to the complexity of the creep buckling analysis. Eventually, creep cavity evaluation technique without identifying the correct stress distribution has been used so often. However, due to the uncertainty of the technique itself plus conservative mindset of the inspectors, it tends to leads to an excessive maintenance most of the cases. In order to conduct a reasonable remaining life assessment, it is desirable to use the creep cavity inspection in conjunction with another assessment technique such as FEM creep analysis as stated in API 579-1/ASME FFS-1 10.5.7. In this paper, comprehensive approach with FEM and field inspection such as creep cavity evaluation to reinforce the uncertainty of each method will be demonstrated.


2021 ◽  
Vol 28 (1) ◽  
pp. 540-554
Author(s):  
Guo Zhang ◽  
Haiyang Zhu ◽  
Qi Wang ◽  
Xiaowen Zhang ◽  
Mingfa Ren ◽  
...  

Abstract The cylindrical filament wound composite overwrapped pressure vessels (COPV) with metal liner has been widely used in spaceflight due to their high strength and low weight. After the autofrettage process, the plastic deformation of the metal liner is constrained by composite winding layers, which introduce depressions to the metal liner that causes local buckling. To predict the local buckling of the inner liner with depressions of the pressure vessel after the autofrettage process, a local buckling analysis method for the metal liner of COPV was developed in this article. The finite element method is used to calculate the overall stress distribution in the pressure vessel before and after the autofrettage process, and the influence of local depressions on the buckling is evaluated. The axial buckling of the pressure vessel under external pressure is analyzed. The control equation of the metal liner with depressions is developed, considering the changes in the pressure and the bending moment of the liner depressions and its vicinity during the loading and unloading process. Taking the cylindrical COPV (38 L) with aluminum alloy liner as an example, the effects of liner thickness, liner radius, the thickness-to-diameter ratio, autofrettage pressure, and the length of straight section on the autofrettage process are discussed. The results show that the thickness of the inner liner has the most significant influence on the buckling of the liner, followed by the length of the straight section and the radius of the inner liner, while the autofrettage pressure has the least influence.


1974 ◽  
Vol 96 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Andre´ Biron ◽  
Jean Veillon

Results are presented for the limit analysis of pressure vessel heads of torispherical and ellipsoidal shapes in order to evaluate the influence of different head thicknesses for a given cylinder thickness. Comparison is made with presently used configurations as recommended by the ASME Code. It is found in particular that increasing the knuckle thickness of a torispherical head would provide a significant increase in yield pressure without excessive additional material.


Author(s):  
Martin Muscat ◽  
Duncan Camilleri ◽  
Brian Ellul

The increase in stiffness to weight ratio and relative ease of manufacturing fibre reinforced composite pressure vessels, have put such vessels at the forefront of technology. However only limited research and specific codes pertaining exclusively to composite pressure vessel design can be found in literature. The ASME Boiler and Pressure Vessel (BPVC) Section X Code and the European design codes EN 13121-3:2016 (GRP tanks and vessels for use above ground) together with EN 13923:2005 (Filament wound FRP pressure vessels — materials, design, manufacturing and testing) are some of the few known design codes applicable to composite pressure vessels. These codes utilise both design by rule (DBR) and design by analysis (DBA) methods. The authors believe that more studies along the DBA route would benefit the composite pressure vessel design community and make it more accessible to designers and engineers. A similar scenario has already been seen in the last 10 to 15 years for steel pressure vessel design codes when DBA based on inelastic analysis was introduced. In line with these thoughts, this study compares the different design methods to prevent buckling and applies finite element analysis (FEA) to analyse a hemispherical GFRP pressure vessel head subjected to external pressure. The effect of material damage and geometrical imperfections on the final collapse failure is examined and discussed.


Author(s):  
Maan Jawad ◽  
Xiaolin Chen ◽  
Donald Griffin

Abstract External Pressure charts are used for the design of most components in pressure vessels and boilers. The External Pressure Charts developed by the ASME Boiler and Pressure Vessel Code in the past for various materials were constructed manually at a fairly long lead time. ASME recently undertook a project to computerize the procedure for constructing External Pressure Charts for new materials at a fraction of the previous construction time. The methodology, assumptions, advantages, and limitations of this procedure are described in this paper.


Author(s):  
Milan Brumovsky

Reactor pressure vessels (RPV) are components with the highest importance for the reactor safety and operation as they contain practically whole inventory of fission material but they are damaged/aged during their operation by an intensive reactor radiation. Surveillance specimen programs are the best method for monitoring changes in mechanical properties of reactor pressure vessel materials if they are designed and operated in such a way that they are located in conditions close to those of the vessels. Reactor Codes and standards usually included requirements and conditions for such programs to assure proper vessel monitoring. WWER (Water-Water-Energetic Reactors) reactor pressure vessels are designed according to former Russian Codes and rules with somewhat different requirements using different materials comparing e.g. with ASME Code. Two principal types of WWER reactors were designed, manufactured and are operated in several European countries (and also in China, Iran): WWER-440 and WWER-1000. Their surveillance programs were designed in quite different way, with some modifications due to the time, country of manufacturing and experience gained from their operation. The paper gives a critical comparison of these programs in both types of reactors with requirements of both Russian and ASME/ASTM Codes and Standards. Finally, information about creation of the Integral Surveillance Program for WWER-1000 type reactor pressure vessels covering vessels from several countries is described.


Author(s):  
Li Wan ◽  
Wei-ming Tao ◽  
Xin-xin Wu ◽  
Shu-yan He

Pressure vessels are widely used in nuclear engineering and buckling is a common mechanical phenomenon in structure. The buckling problem of pressure vessels under external pressure has been researched for many years. This paper focuses on the influence of initial geometric imperfection on the localized elastic-plastic buckling of pressure vessel under internal pressure. The localized plastic buckling occurred in the transition region in the torispherical end closure of a pressure vessel is analyzed by FEM. By introducing two types of initial geometrical imperfections, the arc-length method of modified Riks/Ramm procedure is performed to simulate the buckling process during loading. The first type of imperfection is displacement, into the region where it is circumferentially compressed. The second type of imperfection is the irregular thickness of the vessel, also into the region where it is circumferentially compressed. The initial critical point is captured within the buckled region, and the corresponding initial buckling load is calculated. The results show that both artificial geometric imperfections can seduce the buckling. Furthermore, after the first buckling initiated, the succeeding loading will lead to more wrinkles within the compressive transition region. And then the case that with two distributed imperfections is also analyzed. It can be seen that the interaction between the imperfections is very weak before or even after the first buckling occurred, which means the buckling is fairly localized.


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