The Method of Design by Analysis for Cylindrical Pressure Vessels with Spherically Dished Head

2019 ◽  
Vol 795 ◽  
pp. 262-267
Author(s):  
Zhen Yu Wang ◽  
Jian Wu ◽  
Ming De Xue ◽  
Shi Yu Li
Keyword(s):  
Internal Pressure ◽  
Shell Theory ◽  
Pressure Vessels ◽  
Design Criteria ◽  
Analysis Method ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Nonlinear Elastic ◽  
Theoretical Stress ◽  
Thin Shell Theory

Standards GB 150.3-2011 and JB4732-1995 (Confirmed in 2005) provide design methods for the cylindrical pressure vessels with spherically dished head under internal pressure. It is available for the ratio of the internal pressure p to the allowable stress Sm, p/Sm≥0.002. Engineers desire the design curves for p/Sm<0.002. This paper presents a stress analysis method based on elastic thin shell theory for a spherically dished head jointed to the end or the middle of the cylindrical shell. The design criteria in the current standards are modified. Based on the theoretical stress solution and design criteria, the suitable range of the design curves is extended to p/Sm≥0.001. Nonlinear elastic perfectly-plastic finite element method ensures the reliability of the design curves.

Design-Focused Stress Analysis of Cylindrical Pressure Vessels Intersected by Small-Diameter Nozzles

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Faisal M. Mukhtar ◽  
Husain J. Al-Gahtani
Keyword(s):  
Shell Theory ◽  
Large Diameter ◽  
Small Diameter ◽  
Vessel Diameter ◽  
Theory Of Elasticity ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Overall Design ◽  
Design Charts ◽  
Thin Shell Theory

In a related work previously carried out by the authors, finite element analysis of cylindrical vessel–cylindrical nozzle juncture based on the use of thin shell theory, due to the fact that the intersecting nozzle sizes are moderate to large, have been presented. Such analysis becomes invalid in cases when the nozzles are small in sizes which may result in nozzles whose configuration violates the validity of shell assumption. As a result, use of solid elements (based on theory of elasticity) in modeling the cylindrical vessels with small-diameter nozzles is presented in the present paper. Discussions of the numerical experiments and the results achieved are, first, given. The results are then compared with the prediction by other models reported in the literature. In order to arrive at the overall design charts that cover all the possible ranges of nozzle-to-vessel diameter ratio, the charts for the vessels with moderate-to-large-diameter nozzles are augmented with those of cylindrical vessels intersected by small-diameter nozzles developed in this work.

The Collapse or Ballooning Pressure of Thick-Walled Pressure Vessels

1983 ◽  
Vol 22 ◽  
Author(s):  
B. Crossland
Keyword(s):  
Mild Steel ◽  
Strain Hardening ◽  
Pressure Vessel ◽  
Factor Of Safety ◽  
Plastic Material ◽  
Pressure Vessels ◽  
Bursting Pressure ◽  
Collapse Pressure ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

ABSTRACTDiscussion of the proposed extension of the ASME pressure vessel code to cover operating pressures up to 1.4 GPa (200000 lbf/in2 ) has generated the proposal that two criteria should be used, of which one would be the collapse or ballooning pressure not the bursting pressure. The present paper examines this proposal in relation to extensive data on the collapse and bursting of thick-walled vessels available to the author.It is concluded that the collapse pressure is only readily calculable for materials which approach the behaviour of an elastic/perfectly plastic material. It also appears for materials with significant strain hardening characteristics, such as mild steel, that the collapse pressure considerably underestimates the bursting pressure, whereas for a material which behaves as an elastic/perfectly plastic material the collapse pressure is nearly coincident with the bursting pressure. Consequently if the collapse pressure was adopted and if the factor of safety against collapse was adequate for one material it might be more or less than adequate for another material, which would appear to be unacceptable.

scholarly journals Mechanical Behavior of Interface between Composite Geomembrane and Permeable Cushion Material

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Haimin Wu ◽  
Yiming Shu ◽  
Linjun Dai ◽  
Zhaoming Teng
Keyword(s):  
Three Dimensions ◽  
Deformation Analysis ◽  
Surface Barrier ◽  
Elastic Model ◽  
Lagrangian Analysis ◽  
Direct Shear Tests ◽  
Perfectly Plastic ◽  
Calculation Results ◽  
Elastic Perfectly Plastic ◽  
Nonlinear Elastic

An accurate description of composite geomembrane-cushion interface behavior is of great importance for stress-deformation analysis and stability assessment of geomembrane surface barrier of rock-fill dam. A series of direct shear tests were conducted to investigate the friction behaviors of interfaces between composite geomembrane and two different permeable cushion materials (crushed stones and polyurethane mixed crushed stones). The shear stress-displacement relationships of the two interfaces show different characteristics and were described by the nonlinear-elastic model and nonlinear-elastic perfectly plastic model, respectively. Then the two models were implemented into the Fast Lagrangian Analysis of Continua in Three Dimensions (FLAC3D) procedure correctly. By verification of a numerical example, numerical calculation results showed a good agreement with the theoretical solutions and test results.

Evaluating Plastic Loads in Torispherical Heads Using a New Criterion of Collapse

2006 ◽  
Author(s):  
Duncan Camilleri ◽  
Donald Mackenzie ◽  
Robert Hamilton
Keyword(s):  
Pressure Vessels ◽  
Plastic Collapse ◽  
Total Work ◽  
Medium Thickness ◽  
Material Models ◽  
Hardening Material ◽  
Perfectly Plastic ◽  
Inelastic Analysis ◽  
Elastic Perfectly Plastic ◽  
New Criterion

In ASME Design by Analysis, the plastic load of pressure vessels is established using the Twice Elastic Slope criterion of plastic collapse. This is based on a characteristic load-deformation plot obtained by inelastic analysis. This study investigates an alternative plastic criteria based on plastic work dissipation where the ratio of plastic to total work is monitored. Two sample analyses of medium thickness torispherical pressure vessels are presented. Elastic-perfectly plastic and strain hardening material models are considered in both small and large deformation analyses. The calculated plastic loads are assessed in comparison with experimental results from the literature.

Study on Plastic Collapse Load of Steel Elliptical Heads Under Internal Pressure

2013 ◽  
Author(s):  
Liang Sun ◽  
Guide Deng ◽  
Jiufeng Zhao
Keyword(s):  
Internal Pressure ◽  
Major Axis ◽  
Pressure Vessels ◽  
Outer Diameter ◽  
Maximum Relative Error ◽  
Plastic Collapse ◽  
Collapse Load ◽  
Element Analysis ◽  
Integrity Assessment ◽  
Perfectly Plastic

A general formula for plastic collapse load of elliptical heads under internal pressure is useful in plastic collapse design and integrity assessment of pressure vessels. Plastic collapse load of steel elliptical heads with different shapes and thickness was computed by finite element analysis using elastic-perfectly plastic constitutive model, and a formula with maximum relative error less than 6% was derived from the numerical results. The formula is a function of the yield strength of materials, the ratio of major axis Di to minor axis 2hi and that of outer diameter Do to inner diameter Di, and is applicable to steel elliptical heads with Di/2hi within 1–2.6 and Do/Di within 1.001–1.300.

Some Comments on the Stress Concentration and Shakedown Factors for Spherical Pressure Vessels with Flush Radial Cylindrical Nozzles

1979 ◽  
Vol 21 (3) ◽  
pp. 153-157 ◽  
Author(s):  
M. Robinson
Keyword(s):  
Stress Concentration ◽  
Experimental Work ◽  
Stress Concentration Factor ◽  
Thin Shell ◽  
Shell Theory ◽  
Pressure Vessels ◽  
Simple Design ◽  
Design Proposal ◽  
Thin Shell Theory ◽  
Spherical Pressure

Some previous theoretical shakedown pressures for a cylinder—sphere vessel under internal pressure are, for a certain range of parameters, shown to be too high. The error can be traced to an underestimate of the stress concentration factor owing to the use of the centreline thin-shell theory and the neglect of cylinder stresses. It is shown that much more theoretical and experimental work needs to be done to establish reliable shakedown pressures for a comprehensive range of parameters. A simple design proposal is suggested which should meanwhile prove adequate.

Assessment of Compact Heat Exchanger Design Following Elastic Perfectly Plastic Methodology

2020 ◽  
Author(s):  
Avinash Shaw ◽  
Heramb P. Mahajan ◽  
Tasnim Hassan
Keyword(s):  
Global Analysis ◽  
Local Level ◽  
Primary Objective ◽  
Analysis Method ◽  
Perfectly Plastic ◽  
Heat Exchanger Design ◽  
Creep Fatigue ◽  
Asme Code ◽  
Computationally Intensive ◽  
Elastic Perfectly Plastic

Abstract Compact Heat Exchangers (CHXs) have a large number of miniature channels inside their core, which makes them highly thermal efficient and thus, prime utile for Next Generation Nuclear Plant (NGNP) applications. The fabrication of a CHX involves diffusion, brazed or welded bonding of plates to form CHX block with a channeled core. The elevated temperature and transient conditions of NGNP operation may induce excessive strain and creep-fatigue failure in channel ligaments. The primary objective of this study is to evaluate the design of CHX for application to NGNPs, following the ASME Code Elastic Perfectly Plastic (EPP) Analysis criteria in a draft ASME Code Section III, Division 5 and using the currently available Division 5 Code Cases (N-861 and N-862). As global analysis considering channels in the core is computationally intensive, a new analysis method is evaluated. In this method, the global analysis is performed by representing the channeled core by an elastic orthotropic material core. Subsequently, at the local level, EPP analysis is performed using models that include the channels, with thermal and pressure loading conditions. An ASME Draft Code Case is under development for the construction of CHXs. The analysis results are used to assess proposed stress limits and classification for load controlled stresses. For strain limits, the analysis results are evaluated using Code Cases N-861 and N-862 against the strain limit and creep-fatigue damage using the channel level submodel analysis. The applicability of the new analysis method, and use of the analysis results for evaluation against ASME proposed limits for various regions of the CHX are presented and discussed.

A New Method for Preventing Plastic Collapse of Ellipsoidal Head Under Internal Pressure

2020 ◽  
Author(s):  
Keming Li ◽  
Jinyang Zheng ◽  
Zekun Zhang ◽  
Chaohua Gu ◽  
Ping Xu
Keyword(s):  
Internal Pressure ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Design Methods ◽  
New Method ◽  
Plastic Collapse ◽  
Element Analysis ◽  
Linear Elastic ◽  
Perfectly Plastic ◽  
Margin Of Safety

Abstract Ellipsoidal head is a common end closure of pressure vessel. Plastic collapse is a crucial failure mode considered in the design of ellipsoidal head subjected to internal pressure. Internally pressurized ellipsoidal head tends to be hemisphere (geometric strengthening) due to the effect of material hardening before plastic collapse occurs, which enhances load carrying capacity of ellipsoidal head. However, in the current pressure vessel codes such as ASME BPVC.VIII.1 and BPVC.VIII.2, EN 13445-3, and Chinese codes GB/T 150.3 and JB 4732, design methods based on linear elastic or perfectly-plastic theory are used to prevent plastic collapse of ellipsoidal head, leading to conservative design. Therefore, we developed a new method for preventing plastic collapse of ellipsoidal head under internal pressure, considering the effects of material hardening and geometric strengthening. The new method was developed on basis of our previous extensive work on finite element analysis and experiments for plastic collapse of internally pressurized ellipsoidal heads. The new method provides sufficient margin of safety by checking against the experimental bursting results of full-scale ellipsoidal heads with various geometries, various material types and various manufacturing methods. Compared with the design methods in the current pressure vessel codes, the new method shows an advantage of economy. This new method had been approved by China Standardization Committee on Boilers and Pressure Vessels, and at present it has been introduced into the Chinese pressure vessel code.

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