Design of Conical Shells Under External Loads

1980 ◽  
Vol 102 (2) ◽  
pp. 230-238 ◽  
Author(s):  
M. H. Jawad
Keyword(s):  
Experimental Data ◽  
Design Procedure ◽  
External Pressure ◽  
Moment Of Inertia ◽  
Design Criteria ◽  
Conical Shells ◽  
Division 1 ◽  
Simplified Method ◽  
Section Viii ◽  
External Loads

The background is presented for the rules for conical shells and reducers under external pressure which were recently added to Section VIII, Division 1. A simplified method for the design of conical shells under external pressure is developed from theoretical and experimental data. The design procedure is similar to that published by ASME for cylindrical shells. Design criteria for the conical-to-cylindrical junction is also established in terms of the minimum required area and moment of inertia at the junction.

A Study of the Conservatism in ASME BPVC Section VIII Division 2 Opening Design for External Pressure

2019 ◽  
Author(s):  
Barry Millet ◽  
Kaveh Ebrahimi ◽  
James Lu ◽  
Kenneth Kirkpatrick ◽  
Bryan Mosher
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
External Pressure ◽  
The Other ◽  
Finite Element Analyses ◽  
Division 1 ◽  
Section Viii ◽  
Allowable Compressive Stress ◽  
Division 2

Abstract In the ASME Boiler and Pressure Vessel Code, nozzle reinforcement rules for nozzles attached to shells under external pressure differ from the rules for internal pressure. ASME BPVC Section I, Section VIII Division 1 and Section VIII Division 2 (Pre-2007 Edition) reinforcement rules for external pressure are less stringent than those for internal pressure. The reinforcement rules for external pressure published since the 2007 Edition of ASME BPVC Section VIII Division 2 are more stringent than those for internal pressure. The previous rule only required reinforcement for external pressure to be one-half of the reinforcement required for internal pressure. In the current BPVC Code the required reinforcement is inversely proportional to the allowable compressive stress for the shell under external pressure. Therefore as the allowable drops, the required reinforcement increases. Understandably, the rules for external pressure differ in these two Divisions, but the amount of required reinforcement can be significantly larger. This paper will examine the possible conservatism in the current Division 2 rules as compared to the other Divisions of the BPVC Code and the EN 13445-3. The paper will review the background of each method and provide finite element analyses of several selected nozzles and geometries.

Effect of Reinforcement on the Strength of Junctions Between Cylindrical and Conical Shells

1995 ◽  
Vol 117 (2) ◽  
pp. 135-141 ◽  
Author(s):  
A. Kalnins ◽  
D. P. Updike
Keyword(s):  
Failure Criterion ◽  
Failure Modes ◽  
Low Cycle Fatigue ◽  
Safety Margin ◽  
External Pressure ◽  
Cycle Fatigue ◽  
Conical Shells ◽  
Section Viii ◽  
Cyclic Service ◽  
Reinforcement Distribution

Two failure modes are addressed for cylinder-cone junctions under internal or external pressure: axisymmetric yielding and low-cycle fatigue. If the junction fails to meet the failure criterion of any one of the two modes, then it must be strengthened by reinforcement. It is shown in the paper that the degree to which a junction is strengthened depends on the distribution of the reinforcement. A placement of reinforcement on the cylinder alone, leaving the actual connection between the cylinder and cone unreinforced, adds strength with regard to axisymmetric yielding, but may not strengthen the junction sufficiently with regard to low-cycle fatigue. This means that the junction may appear reinforced, but is not strengthened. It is pointed out that the design rules of Section VIII, Div. 1 of the ASME B & PV Code (1992) set the need for reinforcement according to the failure criterion of low-cycle fatigue, while the distribution of the reinforcement is guided by the criterion of axisymmetric yielding. There is no assurance that the reinforced junction will meet the failure criterion of low-cycle fatigue. This means that the safety margin on the number of allowed cycles is less than that which is expected and that the junction may be unfit for cyclic service. It is also shown in the paper that a reinforcement distribution that requires minimum thicknesses for sections of both the cylinder and cone near the junction can satisfy criteria for both failure modes. This approach is already used in Code Case 2150 of Section VIII, Div. 1, for half-apex cone angles from 30 to 60 deg, and required in Div. 2 for cone angles from 0 to 30 deg. Its extension to angles from 0 to 60 deg for both internal and external pressure is recommended.

A Creep Buckling Design Method of Elliptical Heads Based on the External Pressure Chart

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Fang Liu ◽  
Jian-Guo Gong ◽  
Fu-Hai Gao ◽  
Fu-Zhen Xuan
Keyword(s):  
Design Method ◽  
External Pressure ◽  
Design Approach ◽  
Design Criteria ◽  
Design Factor ◽  
Simplified Method ◽  
Creep Buckling ◽  
Conservative Result

The buckling design criteria of elliptical heads in ASME VIII-1, ASME NH, and RCC-MRx are reviewed and compared. Accordingly, an external pressure chart (EPC) based buckling design approach is developed for elliptical heads in the creep range. Results indicate that for instantaneous buckling design, RCC-MRx predicts higher allowable pressure compared with ASME NH, which is ascribed to the smaller design factor. The proposed method produces a similar result with that given by ASME VIII-1. By contrast, the proposed method leads to a reasonably conservative result with the factor n of 0.03 for the creep buckling design. While the simplified method in RCC-MRx provides an over-conservative solution.

Alternate Design Charts for Fixed Tubesheet Design Procedure Included in ASME Boiler and Pressure Vessel Code, Section VIII, Division 1

1995 ◽  
Vol 117 (2) ◽  
pp. 189-194 ◽  
Author(s):  
T. Kuppan
Keyword(s):  
Pressure Vessel ◽  
Heat Exchangers ◽  
Design Parameter ◽  
Design Procedure ◽  
Tabular Form ◽  
Design Charts ◽  
Division 1 ◽  
Section Viii ◽  
Shell And Tube ◽  
Design Calculations

Design formulas and calculation procedure for the design of fixed tubesheets of shell and tube heat exchangers are included in Appendix AA—Nonmandatory of ASME Boiler and Pressure Vessel Code, Section VIII, Division 1. To minimize the number of calculations, charts are provided as part of the design procedure. This article provides alternate charts for certain parameters and the original version of the charts are extended for larger values of tubesheet design parameter. Numerical values are given in tabular form for certain functions used in plotting the design charts. This will help to do design calculations without referring to the charts.

Stability Design Criterion for Vessels Subjected to Concurrent External Pressure and Longitudinal Compressive Loads

1979 ◽  
Vol 101 (2) ◽  
pp. 178-181
Author(s):  
N. Gilbert ◽  
J. R. Polani
Keyword(s):  
Compressive Stress ◽  
Design Procedure ◽  
Elastic Stability ◽  
External Pressure ◽  
Design Criterion ◽  
Buckling Loads ◽  
Compressive Loads ◽  
Section Viii ◽  
Stability Data ◽  
Allowable Compressive Stress

This paper presents a design procedure for determining the maximum allowable compressive stress and the maximum allowable external pressure for cylindrical vessels subjected to loadings which produce both longitudinal and circumferential stresses simultaneously. Although the ASME Pressure Vessel Code Section VIII [1] mentions the combinations of loadings as a factor in determining the thickness of vessels, the Code procedures (UG-23) for longitudinal compressive stress and (UG-28) for external pressure do not consider the interaction of these two buckling loads when acting concurrently. Calculations of typical vessels subjected to these conditions reveal that adherence to the Code rules without inclusion of these effects may yield results which fall below the safe design limits established by the Code. The design procedure developed herein extends the existing Code formulations as applicable; and incorporates established elastic stability data as necessary.

Code Case 2286 Applied to the Design of Pressure Vessels

2003 ◽  
Author(s):  
Kanhaiya L. Bardia ◽  
Kim Nguyen ◽  
Manfred Lengsfeld ◽  
Donald G. LaBounty ◽  
Bernie Au
Keyword(s):  
Pressure Vessel ◽  
Petrochemical Industry ◽  
External Pressure ◽  
Pressure Vessels ◽  
Compressive Stresses ◽  
Division 1 ◽  
Shell Design ◽  
Asme Code ◽  
Section Viii ◽  
Sample Vessel

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.

The Background of ASME Code Case 1828: A Simplified Method of Analyzing Part B Flanges

1978 ◽  
Vol 100 (2) ◽  
pp. 215-219 ◽  
Author(s):  
R. W. Schneider ◽  
E. O. Waters
Keyword(s):  
Pressure Vessel ◽  
Metal Contact ◽  
Analysis And Design ◽  
Division 1 ◽  
Simplified Method ◽  
Asme Code ◽  
Section Viii ◽  
Consistent Basis

The 1974 Edition of ASME Boiler and Pressure Vessel Code Section VIII, Division 1, provides rules for the analysis and design of identical pairs of Part B flanges (flat face flanges in metal-to-metal contact). The theory has been extended on a consistent basis to cover the analysis of a pair of nonidentical Part B flanges but since the resulting procedure is laborious, action to include the rules has been delayed pending further consideration by the cognizant ASME Code Committees. In the interim a simplified method suitable for analyzing both identical and nonidentical pairs of Part B flanges has been developed and is available as ASME Code Case 1828: “A SIMPLIFIED METHOD FOR ANALYZING PART B FLAT FACE FLANGES WITH METAL-TO-METAL CONTACT OUTSIDE THE BOLT CIRCLE.” The purpose of this paper is to describe the simplified method and to derive some of the more important equations which are contained in the Code Case.

Use of Laser Measurement Systems for Out-of-Roundness Check of ASME BVP Section VIII Div.1 Pressure Vessels

2014 ◽  
Author(s):  
Barry Millet ◽  
Patrizio Di Lillo ◽  
Richard Whipple ◽  
Kenneth Kirkpatrick ◽  
George Miller
Keyword(s):  
Cost Effective ◽  
External Pressure ◽  
Pressure Vessels ◽  
Laser Measurement ◽  
Measuring Systems ◽  
Measurement Systems ◽  
Cost Effective Method ◽  
Division 1 ◽  
Asme Code ◽  
Section Viii

Since the 1956 Edition of the ASME Boiler and Pressure Vessel Code Section VIII (ASME B&PV Code) [1], the Out-of-Roundness of circular sections of pressure vessels subject to external pressure have been inspected using a segmental template per paragraph UG-80(b)(2). Newly approved ASME Code Case 2789 “Laser Measurement for Out-of-Roundness Section VIII, Division 1” to the ASME B&PV Code expands the out of roundness checking to allow the use of laser measurement systems. Today with large vessels approaching 60 feet (18.2 m) in diameter, laser measuring systems allow an expeditious and cost effective method of inspection for out-of-roundness. The Code Case allows the fabricator to use measurements obtained from laser measuring to either verify the vessel in the arc segments or the entire vessel circumference is held to a circularity tolerance. The second option is similar to the requirements of European Standard EN 13445 (EN 13445) [2] which uses circularity. This paper will explore the origin and objective of the template and presents how laser measuring systems make use of the latest technology available to check for out-of-roundness. The paper will address laser measuring systems, procedures for taking measurements, and processing of the data into a format that can be verified by Authorized Inspectors.

Analysis of Shells of Noncircular Cross Section

2004 ◽  
Author(s):  
Jack E. Helms ◽  
Michael W. Guillot
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Thin Wall ◽  
Element Analysis ◽  
Noncircular Cross Section ◽  
Division 1 ◽  
Asme Code ◽  
Minimum Requirements ◽  
Section Viii ◽  
Tank Design

Minimum requirements for the design of shells of noncircular cross section are given in Appendix 13 of Section VIII, Division 1 of the ASME Code. The ASME Section XII Committee is re-examining the design of noncircular shells as part of their activities on cargo tank design. In this study finite element analysis is used to model a thin-wall noncircular shell. The results of the analysis are compared to experimental data provided by RTL, Inc.

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