scholarly journals Allowable Compressive Stress Rules in the ASME Boiler and Pressure Vessel Code, Section VIII, in the Creep Regime

2018 ◽  
Author(s):  
Maan Jawad
Keyword(s):  
Compressive Stress ◽  
Pressure Vessel ◽  
Time Dependent ◽  
Asme Code ◽  
Section Viii ◽  
Allowable Compressive Stress ◽  
Creep Regime

This paper outlines several procedures for developing allowable compressive stress rules in the creep regime (time dependent regime). The rules are intended for the ASME Boiler and Pressure Vessel codes (Sections I and VIII). The proposed rules extend the methodology presently outlined in Sections I, II-D, and VIII of the ASME code for temperatures below the creep regime into temperatures where creep is a consideration.

Elastic Allowable Stress Basis for Elevated Temperature Design in the Creep Regime

2016 ◽  
Author(s):  
Chithranjan Nadarajah ◽  
Benjamin F. Hantz ◽  
Sujay Krishnamurthy
Keyword(s):  
Finite Element ◽  
Elevated Temperature ◽  
Pressure Vessel ◽  
Reasonable Agreement ◽  
Allowable Stress ◽  
Elastic Stresses ◽  
Finite Element Stress Analysis ◽  
Section Viii ◽  
Elevated Temperature Design ◽  
Creep Regime

ASME Section VIII, Division II, Boiler and Pressure Vessel Code does not have any design by analysis procedures for designing pressure vessel components in the creep regime. This publication presents a methodology for evaluating and categorizing elastic stresses calculated from finite element stress analysis when designing in the creep regime. The proposed methodology is compared with multi axial creep results for various pressure vessel components and found to be in reasonable agreement.

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.

Applications of Code Case 2605 for Fatigue Evaluation of Vessels Made in 2.25Cr-1Mo-0.25V Steels Slightly Into Creep Range

2010 ◽  
Author(s):  
Susumu Terada
Keyword(s):  
Fatigue Curve ◽  
Time Dependent ◽  
Inelastic Analysis ◽  
Asme Code ◽  
Section Viii ◽  
Preliminary Study ◽  
Number Of Cycles ◽  
Fatigue Evaluation ◽  
Division 2 ◽  
Made In

The current Section VIII Division 2 of ASME code does not permit method A of paragraph 5.5.2.3 to be used for the exemption from fatigue analysis when the design allowable stress is taken in the time dependent temperature range. Method B of paragraph 5.5.2.4 also cannot be used because it requires the use of the fatigue curve which is limited to 371 ° C and below the needed temperature. Code Case 2605 is a rule for fatigue evaluation of 2.25Cr-1Mo-0.25V steels at temperatures greater than 371 ° C and less than 454 ° C. An inelastic analysis including the effect of creep shall be performed for all pressure parts according to Code Case 2605. Especially, a full inelastic analysis shall be performed using the actual time-dependent thermal and mechanical loading histograms for the lateral nozzle based on preliminary study. It takes much time to perform this inelastic analysis for all full histograms and obtain the fatigue evaluation results when large number of cycles of full pressure is specified in user’s design specification. This paper provides sample analysis results for nozzles and clarifies issue of implementation of Code Case 2605. Then, the proposal of simplification and modification of Code Case 2605 from these results are proposed.

Heat Treatment of Fabricated Components and the Effect on Properties of Materials

2019 ◽  
Author(s):  
Shyam Gopalakrishnan ◽  
Ameya Mathkar
Keyword(s):  
Heat Treatment ◽  
Pressure Vessel ◽  
Test Specimen ◽  
Stress Relieving ◽  
Division 1 ◽  
Asme Code ◽  
Alloy Steels ◽  
Section Viii ◽  
Properties Of Materials ◽  
Division 2

Abstract Most of the heavy thickness boiler and pressure vessel components require heat treatment — in the form of post weld heat treatment (PWHT) and sometimes coupled with local PWHT. It is also a common practice to apply post heating/ intermediate stress relieving/ dehydrogenation heat treatment in case of alloy steels. The heat treatment applied during the various manufacturing stages of boiler and pressure vessel have varying effects on the type of material that is used in fabrication. It is essential to understand the effect of time and temperature on the properties (like tensile and yield strength/ impact/ hardness, etc.) of the materials that are used for fabrication. Considering the temperature gradients involved during the welding operation a thorough understanding of the time-temperature effect is essential. Heat treatments are generally done at varying time and temperatures depending on the governing thickness and the type of materials. The structural effects on the materials or the properties of the materials tends to vary based on the heat treatment. All boiler and pressure vessel Code require that the properties of the material should be intact and meet the minimum Code specification requirements after all the heat treatment operations are completed. ASME Code(s) like Sec I, Section VIII Division 1 and Division 2 and API recommended practices like API 934 calls for simulation heat treatment of test specimen of the material used in fabrication to ascertain whether the intended material used in construction meets the required properties after all heat treatment operations are completed. The work reported in this paper — “Heat treatment of fabricated components and the effect on properties of materials” is an attempt to review the heat treatment and the effect on the properties of materials that are commonly used in construction of boiler and pressure vessel. For this study, simulation heat treatment for PWHT of test specimen for CS/ LAS plate and forging material was carried out as specified in ASME Section VIII Div 1, Div 2 and API 934-C. The results of heat treatment on material properties are plotted and compared. In conclusion recommendations are made which purchaser/ manufacturer may consider for simulation heat treatment of test specimen.

Reliability Factors and Tightness of Tube-to-Tubesheet Joints

1996 ◽  
Vol 118 (2) ◽  
pp. 137-141 ◽  
Author(s):  
Z. F. Sang ◽  
Y. Z. Zhu ◽  
G. E. O. Widera
Keyword(s):  
Pressure Vessel ◽  
Division 1 ◽  
Asme Code ◽  
Section Viii ◽  
Preliminary Study

The main purpose of this paper is to provide an applicable method to establish reliability factors for expanded tube-to-tubesheet joints. The paper also reports on the results of a preliminary study to validate experimentally the reliability efficiencies listed in Table A-2 of Appendix A of Section VIII, Division 1, of the Boiler and Pressure Vessel Code (ASME, 1986), and tightness of expanded tube-tubesheet joints. A comparison between the actual reliability factors fr determined from testing the damage strength of the joint and calculated according to Appendix A-4 of the ASME Code and those of Table A-2 is carried out. The results are discussed in light of the restrictions inherent in Table A-2. It is confirmed that some existing values of fr are conservative, while others are less so.

Closed-Form Solutions for Code Case 2286 Allowable Compressive Stresses Analogous to Vacuum Chart Method

2012 ◽  
Author(s):  
Harsh Kumar Baid ◽  
Donald LaBounty ◽  
Amiya Chatterjee
Keyword(s):  
Closed Form ◽  
Compressive Stress ◽  
Pressure Vessels ◽  
Closed Form Solutions ◽  
Compressive Stresses ◽  
Division 1 ◽  
Section Viii ◽  
Allowable Compressive Stress ◽  
User Friendly

The allowable compressive stresses in pressure vessels can be calculated either from ASME Section VIII Division 1, Paragraph UG-28 vacuum chart method [2] or Code Case 2286 [1]. Code Case 2286 has been incorporated into ASME Section VIII Division 2, Part 5. For Division 1 vessels, the vacuum chart method is a user-friendly tool for determining allowable compressive stress. In this paper, the authors present the development of allowable compressive stress data based on closed-form solutions of Code Case 2286. These closed-form solutions yield exact allowable compressive stress values which are not influenced by any kind of sensitivity. The development presented in the paper is also user-friendly, similar to the vacuum chart, for the determination of allowable compressive stresses. These designs, based on Code Case 2286, are economical without any compromise in the safety of the pressure vessel. Examples are included to demonstrate the results.

Increased Allowable Stresses for Earthquake and Wind Loads in Section VIII, Division 1

1986 ◽  
Vol 108 (4) ◽  
pp. 518-520
Author(s):  
A. Selz
Keyword(s):  
Pressure Vessel ◽  
Wind Loads ◽  
Membrane Stress ◽  
Allowable Stresses ◽  
Division 1 ◽  
Section Viii ◽  
The Subject ◽  
Short Time ◽  
Creep Regime ◽  
Division 2

There has been a need for some time to provide rules for allowable stresses for short-time and infrequent loading such as earthquake and wind loads in Section VIII, Division 1 of the Boiler and Pressure Vessel Code. Such rules exist in Section VIII, Division 2, in Section III, and in many other Codes. Division 1 has been silent on the subject. This has caused some manufacturers to make their own rules, and some to overdesign their hardware. Neither situation is without problems. Therefore, in 1979 the Boiler and Pressure Vessel Committee undertook to develop rules for Section VIII, Division 1. This work resulted in the addition of paragraph UG-23(d) to the Code, in the Summer, 1983 Addenda. The paragraph permits an increase in general primary membrane stress of 20 percent for earthquake and wind loads for temperatures below the creep regime.

Buckling Criteria for Torispherical Heads Under Internal Pressure

2000 ◽  
Vol 123 (3) ◽  
pp. 318-323 ◽  
Author(s):  
Clarence D. Miller
Keyword(s):  
Internal Pressure ◽  
Compressive Stress ◽  
Compressive Strain ◽  
Model Tests ◽  
Accurate Prediction ◽  
The Other ◽  
Upper Limit ◽  
Asme Code ◽  
Section Viii

The results of 190 model tests and failures of five torispherical heads in service are analyzed in this paper. Seventy-two of the heads failed by buckling of the knuckle and 17 of the heads were pressurized until the heads failed by bursting or by rupture of the crown. The test pressures were compared with the design pressures obtained from ASME Section VIII, Divs. 1 and 2 rules which are limited to heads with L/t⩽500, ASME Code Cases 2260 and 2261 rules which are limited to heads with L/t⩽500, the French Code CODAP rules which apply to heads with D/t ratios up to 1000, and the ECCS rules which apply to heads with D/t ratios up to 1250. The margins of safety were found to vary widely for all of the rules. A new set of rules has been developed for design of torispherical heads under internal pressure. The rules are applicable to heads with L/t or D/t ratios up to 2500 and apply to all ASME Code materials. The rules are based on three criteria: failure of the knuckle by buckling, limiting the maximum compressive strain in the knuckle to prevent gross distortions, and failure of the crown by bursting. The proposed rules provide a more accurate prediction of the buckling pressure and a more consistent upper limit on the compressive stress in the knuckle than any of the other rules considered in this paper.

Extension of Fatigue Exemption Rules in Section VIII, Division 2 Slightly Into the Creep Regime

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Charles Becht ◽  
Charles Becht
Keyword(s):  
Pressure Vessel ◽  
Creep Properties ◽  
Simplified Approach ◽  
Fatigue Design ◽  
Allowable Stresses ◽  
Section Viii ◽  
Cyclic Service ◽  
American Society ◽  
Creep Regime ◽  
Division 2

A number of alloys have applications slightly into the creep range that are in cyclic service, such as process reactors. The 2007 edition of Section VIII, Division 2 (2007, ASME Boiler and Pressure Vessel Code, Section VIII, Division 2, The American Society of Mechanical Engineers) provides allowable stresses for these materials, which may be controlled by creep properties. However, the fatigue design rules and fatigue exemption rules are not applicable, precluding the construction of vessels using these materials at temperatures above 370∘C (700∘F). This paper provides a simplified approach for the exemption of low chrome alloys that are slightly into the creep range from fatigue analysis. Part 1 of this paper (Becht, C., 2009, “Elevated Temperature Shakedown Concepts,” ASME J. Pressure Vessel Technol. 133, p. 051203) describes shakedown concepts, which are the basis for the criteria evaluated in this paper.

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.

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