Validating FEA Simulations of Structural Collapse of a Complex Vessel Geometry

2016 ◽  
Author(s):  
J. Adin Mann ◽  
Brandon Yost ◽  
Gregory Westwater ◽  
Christopher R. Johnson ◽  
Brett Pollock ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Complex Geometry ◽  
Control Valve ◽  
Structural Collapse ◽  
Working Pressure ◽  
Element Analysis ◽  
Testing Procedures ◽  
Linear Elastic ◽  
Section Viii ◽  
The Difference

Part 5 in Section VIII Division 2 of the ASME Boiler & Pressure Vessel Code provides methods for evaluating stresses in pressure vessel components using Finite Element Analysis (FEA). Both linear elastic and inelastic methods are provided. Validating the FEA simulations can be challenging because of testing procedures as well as variation between the test parts. Control valve bodies, which have a complex geometry, were tested to pressures far beyond the maximum allowable working pressure to evaluate behavior at structural collapse. The test bodies were scanned so that the true geometry was used in the FEA simulations. FEA simulations were used to perform a linear elastic evaluation and inelastic evaluations. The inelastic evaluation included various material models. The difference between a point by point comparison and outcome based validation are discussed.

Simplified Stress Categorization Using a Single Linear Elastic Analysis

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
M. M. Hossain ◽  
W. D. Reinhardt ◽  
R. Seshadri
Keyword(s):  
Pressure Vessel ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Limit Load ◽  
Element Analysis ◽  
Elastic Stresses ◽  
Linear Elastic ◽  
Wide Range ◽  
Tangent Method ◽  
Classification Tool

The ASME Boiler and Pressure Vessel Code (code) provides guidelines for the classification of linear elastic stresses into primary, secondary, and peak stresses. Although these guidelines cover a wide range of pressure containing components, the guidelines are sometimes difficult to employ for three-dimensional components with complex geometry. This paper uses the mα-tangent method, an assessment of constraint in the component, based on limit load multiplier estimates as a stress classification tool. The method is applied to several practical pressure vessel components from simple to relatively complex geometric configurations. The results compare well with those obtained by conventional techniques, e.g., inelastic finite element analysis.

A Procedure for Non-Linear Structural Collapse Analysis

2014 ◽  
Author(s):  
Shengming Zhang ◽  
Lei Jiang
Keyword(s):  
Structural Engineering ◽  
Standard Procedure ◽  
Analysis Procedure ◽  
Structural Collapse ◽  
Element Analysis ◽  
Collapse Analysis ◽  
Non Linear ◽  
Mesh Density ◽  
The Difference ◽  
Offshore Industry

It is a normal practice nowadays in structural engineering, including ships and offshore industry, to perform non-linear finite element analysis to assess the structure’s capacity for design or evaluation purposes. However, experience has shown that the quality and accuracy of the non-linear FE analysis results are highly dependent on the skill of the person performing the analysis and the analysis procedure used. The difference between results obtained by different people can be significant. In some cases, the results can be misleading. It is considered that a unified procedure is necessary. This paper is moving a step further and trying to develop a standard procedure which can provide a guideline for structural collapse analysis of stiffened panels under any load combinations. The paper provides the technical background on the analysis procedure and the key steps such as model extent, mesh density, initial imperfections, and boundary conditions. Analysis examples are provided in the paper for reference and discussions.

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.

Design of Ellipsoidal Heads Using Elastic-Plastic Finite Element Analysis

2002 ◽  
Author(s):  
Donald J. Florizone
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Large Strain ◽  
Large Diameter ◽  
Spherical Shape ◽  
Element Analysis ◽  
Perfectly Plastic ◽  
Section Viii ◽  
Design Calculations

Traditional design techniques result in excess material being required for ellipsoidal heads. The 2001 ASME Boiler and Pressure Vessel Code Section VIII Division 1, UG-32D and Section VIII Division 2, AD-204 limit the minimum design thickness of the heads. ASME Boiler and Pressure Vessel Code Case 2261 provides alternate equations that enable thinner head design thickness. VIII-2 Appendix 3 and 4 methods potentially could be used to further optimize the head thickness. All the equations in the code use one thickness for the entire head. On large diameter thin heads the center or spherical area is often thicker than the knuckle area due to the method of manufacture. Including this extra material in the design calculations results in an increase of the MAWP of large diameter thin heads. VIII-2, AD-200 of the code permits localized thinning in a circumferential band in a cylindrical shell. Applying these same rules to elliptical heads would permit thinning in the knuckle region as well. Engineers have powerful finite element analysis tools that can be used to accurately determine levels of plastic strain and plastic deformed shapes. It is proposed that VIII-2 Appendix 4 and 5 methods be permitted for the design of elliptical heads. Doing so would permit significant decreases in thickness requirements. Different methods of Plastic Finite Element Analysis (PFEA) are investigated. An analysis of a PVRC sponsored burst test is done to develop and verify the PFEA methods. Two designs based on measurements of actual vessels are analyzed to determine the maximum allowable working pressures (MAWP) for thick and thin heads with and without local thin regions. MAWP is determined by limit analysis, per VIII-2 4-136.3 and by two other proposed methods. Using Burst FEA, the calculated burst pressure is multiplied by a safety factor to obtain MAWP. Large deflection large strain elastic perfectly plastic limit analyses (LDLS EPP LL) method includes the beneficial effect of deformations when determining the maximum limit pressure. Elliptical heads become more spherical during deformation. The spherical shape has higher pressure restraining capabilities. An alternate design equation for elliptical heads based on the LDLS EPP LL calculations is also proposed.

Qualification of a Jacketed Vessel Using Finite Element Analysis

2003 ◽  
Author(s):  
Yogeshwar Hari ◽  
Ram Munjal ◽  
Chawki Obeid
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
External Pressure ◽  
Element Analysis ◽  
Ring Location ◽  
Section Viii ◽  
Specific Configuration ◽  
Inner Vessel ◽  
Vessel Bottom

The main objective of this paper is to improve a jacketed vessel. The jacketed vessel is usually chosen to heat the contents of the vessel. The chamber or annulus contains fluid under pressure to heat the inner vessel contents. The initial over-all dimensions of the vessel are based on the capacity of the stored liquid. The design was in accordance with the ASME Boiler & Pressure Vessel Code, Section VIII, Div 1. The jacketed vessel bottom head and jacket bottom head are being improved to withstand internal and external design pressures. Bottom head of the jacket can be reinforced in one of the three ways, namely: (1) rings which are radial (these rings also create flow for the fluid); (2) attachment of the rings to the bottom jacket head with stays, since rings cannot be physically welded to the bottom jacket; or (3) there is a possibility, the new bottom head and jacketed head combination can be cast, but that would not be economically feasible. This leads to the following six configurations considered in this paper and they are: (1) internal pressure of 50 psi, (2) external pressure + vacuum pressure of 65 psi, (3) reinforcement with 5 rings with external pressure of 65 psi, (4) rings welded with the bottom jacket head with external pressure of 65 psi, (5) welded with stays on ring location (stay diameter of 1 inch) with external pressure of 65 psi, and (6) welded with stays on ring location (stay diameter of 1.5 inch) with external pressure of 65 psi. The pattern of stays chosen for this analysis is one of uniform distribution on ring locations, which are radially situated. The design dimensions based on Code sizing are used to recalculate the stresses for the jacket vessel. The dimensional jacketed vessel is modeled using STAAD III Finite Element Analysis (FEA) software. The design is found to be safe for the specific configuration considered herein with stays.

Overview of Revisions to the ASME Boiler and Pressure Vessel Code Section VIII Division 3 for the 2015 Edition and Near Future

2015 ◽  
Author(s):  
Daniel Peters ◽  
Adam P. Maslowski
Keyword(s):  
High Pressure ◽  
Stress Analysis ◽  
Pressure Vessel ◽  
Elastic Stress ◽  
Pressure Vessels ◽  
Chemical Safety ◽  
Linear Elastic ◽  
Section Viii ◽  
American Society ◽  
Near Future

This paper is to give an overview of the major revisions pending in the upcoming 2015 edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) Section VIII Division 3, Alternative Rules for Construction of High Pressure Vessels, and potential changes being considered by the Subgroup on High Pressure Vessels (SG-HPV) for future editions. This will include an overview of significant actions which will be included in the upcoming edition. This includes action relative to test locations in large and complex forgings, in response to a report from the U.S. Chemical Safety and Hazard Investigation Board (CSB) report of a failed vessel in Illinois. This will also include discussion of a long term issue recently completed on certification of rupture disk devices. Also included will be a discussion of a slight shift in philosophy which has resulted in the linear-elastic stress analysis section being moved to a Non-Mandatory Appendix and discussion of potential future of linear-elastic stress analysis in high pressure vessel design.

Analysis of Stress Intensity Factor and Crack Propagation for Alloy X-750 Pressure Vessel with a Blunting Crack

2010 ◽  
Vol 303-304 ◽  
pp. 63-83
Author(s):  
Ehsan Mahdavi ◽  
Mahmoud Mosavi Mashhadi ◽  
M. Amidpour
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Crack Growth ◽  
Pressure Vessel ◽  
Element Analysis ◽  
Linear Elastic ◽  
The Stability

It is well known that the crack growth rate fatigue and stress corrosion cracking can be approximated by a power function of the stress intensity factor. In this study, stress intensity factor for elliptical crack under the uniform tension in linear elastic fracture mechanics (LEFM) is investigated therefore for this purpose, a pressure vessel modeled by finite element. A crack modeled on the pressure vessel and then the stress intensity factor for crack propagation in different methods is evaluated. Finite element analysis calculates stress intensity factor in the values of the J-integral are based on the stress intensity factors, JK, and by evaluating the contour integral directly, JA. The stability of crack growth is considered so the ductile crack extension is determined by pursuing the equilibrium between loading and crack resistance. Using especial method of meshing caused to have accurate results. This method causes to decrease run time and considerable accuracy. Then stress intensity factor is calculated for different position of the crack such as crack front and then compared to each other.

Calculation of Working Pressure for Cylindrical Vessel Under External Pressure

2010 ◽  
Author(s):  
Gurinder Singh Brar ◽  
Yogeshwar Hari ◽  
Dennis K. Williams
Keyword(s):  
Monte Carlo ◽  
Cylindrical Shell ◽  
Pressure Vessel ◽  
External Pressure ◽  
Working Pressure ◽  
Geometric Imperfections ◽  
The Monte Carlo Method ◽  
Cylindrical Pressure Vessel ◽  
Section Viii ◽  
Initial Geometric Imperfections

Initial geometric imperfections have a significant effect on the load carrying capacity of asymmetrical cylindrical pressure vessels. This research paper presents a comparison of a reliability technique that employs a Fourier series representation of random asymmetric imperfections in a defined cylindrical pressure vessel subjected to external pressure. Evaluations as prescribed by the ASME Boiler and Pressure Vessel Code, Section VIII, Division 2 rules are also presented and discussed in light of the proposed reliability technique presented herein. The ultimate goal of the reliability type technique is to statistically predict the buckling load associated with the cylindrical pressure vessel within a defined confidence interval. The example cylindrical shell considered in this study is a fractionating tower for which calculations have been performed in accordance with the ASME B&PV Code. The maximum allowable external working pressure of this tower for the shell thickness of 0.3125 in. is calculated to be 15.1 psi when utilizing the prescribed ASME B&PV Code, Section VIII, Division 1 methods contained within example L-3.1. The Monte Carlo method as developed by the current authors and published in the literature is then used to calculate the maximum allowable external working pressure. Fifty simulated shells of geometry similar to the example tower are generated by the Monte Carlo method to calculate the nondeterministic buckling load. The representation of initial geometric imperfections in the cylindrical pressure vessel requires the determination of appropriate Fourier coefficients. The initial functional description of the imperfections consists of an axisymmetric portion and a deviant portion that appears in the form of a double Fourier series. Multi-mode analyses are expanded to evaluate a large number of potential buckling modes for both predefined geometries and the associated asymmetric imperfections as a function of position within a given cylindrical shell. The method and results described herein are in stark contrast to the dated “knockdown factor” approach currently utilized in ASME B&PV Code.

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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