Applicability of Design Rules for Openings in Shells, ASME B&PV Code, Section VIII, Division 2 - A Case Study

2021 ◽  
Author(s):  
Gurumurthy Kagita ◽  
Krishnakant V. Pudipeddi ◽  
Subramanyam V. R. Sripada
Keyword(s):  
Stress Analysis ◽  
Failure Modes ◽  
Element Analysis ◽  
Design Rules ◽  
Area Method ◽  
Replacement Method ◽  
Local Stresses ◽  
Pressure Area ◽  
Section Viii ◽  
Division 2

Abstract The Pressure-Area method is recently introduced in the ASME Boiler and Pressure Vessel (B&PV) Code, Section VIII, Division 2 to reduce the excessive conservatism of the traditional area-replacement method. The Pressure-Area method is based on ensuring that the resistive internal force provided by the material is greater than or equal to the reactive load from the applied internal pressure. A comparative study is undertaken to study the applicability of design rules for certain nozzles in shells using finite element analysis (FEA). From the results of linear elastic FEA, it is found that in some cases the local stresses at the nozzle to shell junctions exceed the allowable stress limits even though the code requirements of Pressure-Area method are met. It is also found that there is reduction in local stresses when the requirement of nozzle to shell thickness ratio is maintained as per EN 13445 Part 3. The study also suggests that the reinforcement of nozzles satisfy the requirements of elastic-plastic stress analysis procedures even though it fails to satisfy the requirements of elastic stress analysis procedures. However, the reinforcement should be chosen judiciously to reduce the local stresses at the nozzle to shell junction and to satisfy other governing failure modes such as fatigue.

Development of Design Rules for Nozzles in Pressure Vessels for the ASME B&PV Code, Section VIII, Division 2

2011 ◽  
Author(s):  
Zhenning Cao ◽  
Les Bildy ◽  
David A. Osage ◽  
J. C. Sowinski
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessels ◽  
Experimental Results ◽  
Working Pressure ◽  
Element Analysis ◽  
Design Rules ◽  
Pressure Area ◽  
Section Viii ◽  
Division 2

The theory behind the pressure-area method that is incorporated in the ASME B&PV Code, Section VIII-2 is presented in this paper. Background and insight to the nozzle rules of ASME B&PV Code, Section VIII, Division 2, Part 4, paragraph 4.5 are also provided. Recommendations for modifying the current nozzles rules, those published in ASME B&PV Code, Section VIII, Division 2, 2010 Edition, is given based on continuing research and development efforts. A comparison between experimental results, results derived from detailed finite element analysis (FEA), the rules prior to the VIII-2 Rewrite (2004 Edition), and the rules in VIII-2 are provided in terms of a design margin and permissible maximum allowable working pressure (MAWP) computed with the design rules. A complete description of the theory including a commentary and comparison to experimental results is provided in WRC529 [1].

A Comparative Study of Pressure Area Method of Nozzle Compensation in ASME Section VIII Division 2 and PD 5500 for Restrictions in Nozzle Dimensions

2018 ◽  
Author(s):  
Shyam Gopalakrishnan ◽  
Ameya Mathkar
Keyword(s):  
Comparative Study ◽  
Shell Height ◽  
Applied Pressure ◽  
Design Procedure ◽  
Area Method ◽  
Code Of Practice ◽  
Pressure Area ◽  
European Code ◽  
Section Viii ◽  
Division 2

Clause 4.5 of ASME Section VIII Division 2[1] provides rules for compensation of openings in cylindrical shells having fitted nozzles. The rules provided in Clause 4.5.5 of ASME Section VIII Division 2[1] are based on pressure-area method which is based on ensuring that the reactive force provided by the vessel material is greater than or equal to the load from the pressure. Clause 3.5.4 of PD 5500[5] provides rules for compensation of opening and nozzle connections. Clause 3.5.4.3 provides requirements for the design of isolated openings and nozzle connections in the form of design procedure. Clause 3.5.4.4 provides requirements for groups of openings and the procedure allows the checking of chosen geometry. Clause 3.5.4.9 of PD 5500[5] provides rules for compensation of openings by pressure-area method to those geometries which confirms to the geometric limitations specified therein. This method has extensive satisfactory use in European Code of practice and has been adopted in BS EN 13445-3 also. The key element in applying the pressure area method is to determine the dimensions of the reinforcing zone, i.e., the length of the shell, height of the nozzle and reinforcing pad dimensions (if reinforcing pad is provided), that resist the applied pressure. In comparison to certain restrictions in PD 5500[5] there appears to be no restriction on the physical dimensions of the nozzle or shell in ASME Section VIII Division 2[1], as long as the required area AT is obtained and the stresses are within allowable limits. It is therefore possible that all of the required area AT is obtained either from the nozzle or from the shell. While both these alternatives would be acceptable in ASME Section VIII Division 2[1] design, the actual stresses at the shell/nozzle junction may vary considerably. The work reported in this paper — a comparative study of pressure area method of nozzle compensation in ASME Section VIII Division 2[1] and PD 5500[5] for restrictions in nozzle dimensions was undertaken to compare the results obtained from both the Codes and is an extension of work carried out and published as PVP2015-45564.

A Comparison of Design by Analysis Techniques for Evaluating Nozzle-to-Shell Junctions per ASME Section VIII Division 2

2015 ◽  
Author(s):  
Phillip E. Prueter ◽  
Robert G. Brown
Keyword(s):  
Stress Analysis ◽  
Failure Modes ◽  
Elastic Stress ◽  
Limit Load ◽  
Plastic Collapse ◽  
Elastic Plastic ◽  
Plastic Analysis ◽  
Non Linear ◽  
Section Viii ◽  
Division 2

Part 5 of ASME Section VIII Division 2 offers several design by analysis (DBA) techniques for evaluating pressure retaining equipment for Code compliance using detailed computational stress analysis results. These procedures can be used to check components for protection against multiple failure modes, including plastic collapse, local failure, buckling, and cyclic loading. Furthermore, these procedures provide guidance for establishing consistent loading conditions, selecting material properties, developing post-processing techniques, and comparing analysis results to the appropriate acceptance criteria for a given failure mode. In particular, this study investigates the use of these methods for evaluating nozzle-to-shell junctions subjected to internal pressure and nozzle end loads. Specifically, elastic stress analysis, limit load analysis, and elastic-plastic stress analysis are utilized to check for protection against plastic collapse, and computational results for a given load case are compared. Additionally, the twice elastic slope method for evaluating protection against plastic collapse is utilized as an alternate failure criterion to supplement elastic-plastic analysis results. The goal of these comparisons is to highlight the difference between elastic stress checks and the non-linear analysis methodologies outlined in ASME Section VIII Division 2; particularly, the conservatism associated with employing the elastic stress criterion for nozzle end loads compared to limit load and elastic-plastic analysis methodologies is discussed. Finally, commentary on the applicability of performing the Code-mandated check for protection against ratcheting for vessels that do not operate in cyclic service is provided. The intent of this paper is to provide a broad comparison of the available DBA techniques for evaluating the acceptability of nozzle-to-shell junctions subjected to different types of loading for protection against plastic collapse. Predicted deformations and stresses are quantified for each technique using linear and non-linear, three-dimensional finite element analysis (FEA) methodologies.

User’s Design Specification Preparation for 2¼Cr-1Mo-¼V Reactors in Accordance With ASME Section VIII, Division 2 Code and Code Case 2605

2013 ◽  
Author(s):  
Radoslav Stefanovic ◽  
Alicia Avery ◽  
Kanhaiya Bardia ◽  
Reza Kabganian ◽  
Vasile Oprea ◽  
...  
Keyword(s):  
Operating Temperature ◽  
Design Specification ◽  
Element Analysis ◽  
Analysis And Evaluation ◽  
Reheat Cracking ◽  
Inelastic Analysis ◽  
Allowable Stresses ◽  
Section Viii ◽  
Fatigue Evaluation ◽  
Division 2

Today’s hydroprocessing reactor manufacturers use 2¼Cr–1Mo–¼V steel to build lighter reactors than conventional Cr-Mo reactors. Manufacturing even lighter hydroprocessing reactors has been enabled with the introduction of the new ASME Section VIII Division 2 Code, initially released in 2007. The higher allowable stresses in the new Division 2 for these Vanadium-modified steels permits even lighter reactors to be built while maintaining suitable design margins. The new Division 2 Code requires additional engineering to ensure safe design. One of the challenges the engineer is faced with, is preparation of the User’s Design Specification (UDS) including new and more stringent requirements for fatigue evaluation. As the operating temperature of the rector is higher than 371°C, engineers have to evaluate the fatigue life of the reactor in accordance with Code Case 2605 (CC2605). CC2605 requires inelastic analysis and evaluation effects of creep. Vanadium-modified reactors require additional care during fabrication to prevent higher hardness around weld areas, reheat cracking, and reduced toughness at lower temperatures in the “as welded” condition. This paper provide guidance for the preparation of an ASME Section VIII Division 2 User’s Design Specification including process descriptions of all the cycles expected for the life of the rector and analysis requested by CC2605. An example of such an analysis, including finite element analysis results, is provided in this paper. Requirements to provide the material specification is also discussed with an emphasis on prevention of reheat cracking, hardenability, and temper and hydrogen embitterment.

A New Method of Stress Linearization for Design by Analysis in Pressure Vessel Design

2014 ◽  
Vol 598 ◽  
pp. 194-197
Author(s):  
Hong Jun Li ◽  
Qiang Ding ◽  
Xun Huang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
New Method ◽  
Stress Distributions ◽  
Bending Stress ◽  
Element Analysis ◽  
Stress Tensors ◽  
Section Viii ◽  
Division 2

Stress linearization is used to define constant and linear through-thickness FEA (Finite Element Analysis) stress distributions that are used in place of membrane and membrane plus bending stress distributions in pressure vessel Design by Analysis. In this paper, stress linearization procedures are reviewed with reference to the ASME Boiler & Pressure Vessel Code Section VIII Division 2 and EN13445. The basis of the linearization procedure is stated and a new method of stress linearization considering selected stress tensors for linearization is proposed.

Stress Classification Using the R-Node Method

2006 ◽  
Author(s):  
Ihab F. Z. Fanous ◽  
R. Seshadri
Keyword(s):  
Experimental Data ◽  
Complex Geometries ◽  
Element Analysis ◽  
Shell Elements ◽  
Linear Elastic ◽  
Stress Classification ◽  
Wide Range ◽  
Asme Code ◽  
Section Viii ◽  
Division 2

The ASME Code Section III and Section VIII (Division 2) provide stress classification guidelines to interpret the results of a linear elastic finite element analysis. These guidelines enable the splitting of the generated stresses into primary, secondary and peak. The code gives some examples to explain the suggested procedures. Although these examples may reflect a wide range of applications in the field of pressure vessel and piping, the guidelines are difficult to use with complex geometries. In this paper, the r-node method is used to investigate the primary stresses and their locations in both simple and complex geometries. The method is verified using the plane beam and axisymmetric torispherical head. Also, the method is applied to analyze 3D straight and oblique nozzle modeled using both solid and shell elements. The results of the analysis of the oblique nozzle are compared with recently published experimental data.

Improved Construction of Multilayer Vessels to Apply the ASME Code Section VIII, Division 2

1975 ◽  
Vol 97 (1) ◽  
pp. 14-21
Author(s):  
T. Yamauchi
Keyword(s):  
Thermal Conductivity ◽  
Stress Analysis ◽  
Test Piece ◽  
Solid Wall ◽  
Nondestructive Inspection ◽  
Construction Method ◽  
Asme Code ◽  
Welding Part ◽  
Section Viii ◽  
Division 2

It has been made possible to design the multilayered vessel by employing stress analysis according to ASME Section VIII, Division 2, using the construction method of reinforcing the flexual rigidity at the discontinuous part, and assuring the shell thermal conductivity to some fraction of the solid wall shell. Nondestructive inspection for the welding part has been tested to improve the construction method by the test piece.

Effect of Nozzle Dimensions on the Stresses in Compensated Openings in Cylindrical Shells

2015 ◽  
Author(s):  
Dipak K. Chandiramani ◽  
Shyam Gopalakrishnan ◽  
Ameya Mathkar
Keyword(s):  
Cylindrical Shells ◽  
Shell Height ◽  
Applied Pressure ◽  
Reactive Force ◽  
Area Method ◽  
Pressure Area ◽  
Section Viii ◽  
Vessel Material ◽  
Definition Of ◽  
Physical Dimensions

Clause 4.5 of ASME Section VIII Div. 2 [1] provides rules for compensation of openings in cylindrical shells having fitted nozzles. There appears to be no definition of “nozzle” in either ASME Section VIII Div. 2 or ASME Section VIII Div. 1 [2]. The rules provided in Clause 4.5.5 of ASME Section VIII Div. 2 are based on pressure area method which ensures that the reactive force provided by the vessel material is greater than or equal to the load from the pressure. The key element in applying this method is to determine the dimensions of the reinforcing zone, i.e, the length of the shell, height of the nozzle and reinforcing pad dimensions (if reinforcing pad is provided), that resist the applied pressure. There appears to be no restriction on the physical dimensions of the nozzle or shell, so long as the required area AT is obtained and the stresses are within allowable limits. It is therefore possible that all of the required area AT is obtained from the nozzle or from the shell. While both these alternatives would be acceptable, the actual stresses at the shell/nozzle junction may vary considerably. The work reported in this paper was undertaken with a view to determining if there needs to be any restriction on the proportion of area contributed by shell or nozzle to ensure that actual stresses were within allowable limits.

Comparison of Applicable Codes and Standards for Design of End Bulkheads of Pipe-in-Pipe Systems

2013 ◽  
Author(s):  
Soheil Manouchehri ◽  
Jason Potter
Keyword(s):  
Hydrate Formation ◽  
Protective Layer ◽  
Primary Objective ◽  
Third Party ◽  
Wax Deposition ◽  
Element Analysis ◽  
Section Viii ◽  
Code Changes ◽  
Division 2 ◽  
Double Wall

Pipe-In-Pipe (PIP) systems are increasingly used where the primary objective is to prevent wax deposition and/or hydrate formation and to achieve a low Overall Heat Transfer Coefficient (OHTC) value. PIP systems are also increasingly considered as an additional protective layer against loss of containment (e.g. in Arctic pipelines) or to withstand the interaction of a third party (e.g. trawl gear impact) in lieu of costly pipeline burial. At the end of each PIP section, either at a midline connection or end point tie-in, bulkheads are used as a way of transition from a double wall (PIP) system to a single wall (hub in the subsea structure) system. End bulkheads are designed using detailed Finite Element Analysis (FEA) in accordance with more stringent Pressure Vessel Codes (PVC) and manufactured by forging followed by heat treatment and detailed machining to the required dimensions. As the design of end bulkheads does not fall under the Pipeline Codes, a distinction (so called “code break”) may be required on where the governing code changes from the PVC to a Pipeline Code. This paper firstly discusses the application and validity of internationally known PVCs (ASME BPVC Section VIII Division 2 [1], BS EN 13445 [2], PD 5500 [3]) that can be used in the design of end bulkheads. This is then shown in practice by using an example of a typical end bulkhead, designed to various PVCs. Finally, results are compared and conclusions and recommendations are made.

Comparison of Design by Analysis Methods

2006 ◽  
Author(s):  
Sebastian Schindler
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Advantages And Disadvantages ◽  
Direct Route ◽  
Analysis Methods ◽  
Air Cooler ◽  
Section Viii ◽  
Division 2

The paper discusses the advantages and disadvantages of the two well known Design by Analysis methods for unfired pressure vessels: the stress categorisation method (as given e.g. in the 2004 ASME B&BV Code Section VIII Division 2 [1], and EN 13445-3 Annex C [2]) and the new Direct Route (using elastic-plastic finite-element analysis) as given in EN 13445-3 Annex B [2]. A comparison of results is given for examples of various degree of difficulty to show the principal ideas and the applicability of the two approaches: a dished end with a nozzle in the knuckle region, a cylindrical shell to flat end connection and a rather complex header of an air cooler with rectangular cross section. As shown by the considered examples, the Direct Route method gives unique solutions (which is not always the case for stress categorisation) and can be advantageous in some cases, but requires a more time consuming analysis. The questionable design limits given by the 3f-criterion of the stress categorisation method can be avoided by usage of the progressive plastic deformation design check of the Direct Route if the required number of action cycles is low.

Sign in / Sign up

Export Citation Format

Share Document