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.

Stress Categorization Using the Reference Two-Bar Structure

2007 ◽  
Author(s):  
M. M. Hossain ◽  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Three Dimensional ◽  
Complex Loading ◽  
Finite Element Analyses ◽  
Number Of Components ◽  
Elastic Stresses ◽  
Linear Elastic ◽  
Geometric Configurations ◽  
Wide Range

The ASME Boiler and Pressure Vessel Codes and Standards used for designing pressure vessel and piping provide guidelines to classify the linear elastic stresses into primary, secondary and peak categories. Although these guidelines cover a wide range of pressure components, they are sometimes difficult to apply to the three-dimensional components with complex loading and geometries. The concept of “reference two-bar structure” is used in this paper to categorize the stresses in pressure components and structures, using linear elastic finite element analyses. The method is applied to a number of components and structures from simple to relatively complex geometric configurations. The results compare well with those obtained from commercial finite element codes.

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.

Use of Limit Load Analysis for Design of Pressure Vessel Cover

2012 ◽  
Author(s):  
Rahul Jain
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Limit Load ◽  
Plastic Limit ◽  
Element Analysis ◽  
Linear Elastic ◽  
Reference Volume ◽  
Plastic Limit Load ◽  
Load Analysis

This paper explores the use of limit load analysis methods for the design of a pressure vessel manway cover as per the ASME boiler and pressure vessel code guidelines. The results of elastic and limit load finite element analysis are discussed for the design. The concept of reference volume consideration along with linear elastic finite element analysis to determine the lower bound limit load has been explored and the results are compared with the non-linear elastic-plastic limit load analysis.

Simplified Limit Load Determination Using the mα-Tangent Method

2008 ◽  
Author(s):  
R. Seshadri ◽  
M. M. Hossain
Keyword(s):  
Finite Element ◽  
Rapid Determination ◽  
Limit Load ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Limit Loads ◽  
Linear Elastic ◽  
Tangent Method ◽  
Mechanical Components

Limit load determination of mechanical components and structures by the mα-tangent method is proposed herein. The proposed technique is a simplified method that enables rapid determination of limit loads for a general class of mechanical components and structures. The method makes use of statically admissible stress field based on a linear elastic finite element analysis to estimate the limit loads. The method is applied to a number of mechanical component configurations and the results compare well with those obtained by the corresponding elastic-plastic finite element analyses results.

Reference Volume Consideration in the mα-Tangent Method Based Linear Elastic Analysis

2011 ◽  
Author(s):  
R. Adibi-Asl ◽  
M. M. Hossain ◽  
S. L. Mahmood ◽  
P. S. R. Gudimetla ◽  
R. Seshadri
Keyword(s):  
Finite Element ◽  
Rapid Determination ◽  
Limit Load ◽  
Elastic Analysis ◽  
Element Analysis ◽  
Limit Loads ◽  
Linear Elastic ◽  
Reference Volume ◽  
Tangent Method

Limit loads for pressure components are determined on the basis of a single linear elastic finite element analysis by invoking the concept of kinematically active (reference) volume in the context of the “mα-tangent” method. The resulting technique enables rapid determination of lower bound limit load for pressure components by eliminating the kinematically inactive volume. This method is applied to a number of practical components with different percentages of inactive volume. The results are compared with the corresponding inelastic finite element results, or available analytical solutions.

Three-Dimensional Stress Criteria—Summary of the PVRC Project

1999 ◽  
Vol 122 (1) ◽  
pp. 105-109 ◽  
Author(s):  
Greg Hollinger ◽  
John Hechmer
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Research Council ◽  
Failure Modes ◽  
Three Dimensional ◽  
Analytical Techniques ◽  
Element Analysis ◽  
Elastic Stresses ◽  
Work Done ◽  
Stress Criteria

This paper summarizes work done by the Pressure Vessel Research Council (PVRC) on three-dimensional stress criteria, using primarily elastic two and three-dimensional analytical techniques, finite element analysis. The focus of the work was to recommend guidelines on evaluation of elastic stresses relative to the ASME Boiler and Pressure Vessel Code (Code) defined failure modes as they relate to stress limits. The guidelines are developed such that they may be used to update and expand the procedures for evaluating the required stress limits in Code Section VIII, Division 2 and Code Section III, Subsection NB. This paper summarizes the recommendation using ten guidelines. The project addresses eleven example problems, nine of which include finite element analyses. These example problems validate the recommendations. The detailed information is published in the Welding Research Council Bulletin 429, “3-D Stress Criteria Guidelines for Applications.” [S0094-9930(00)01601-2]

Simplified Limit Load Determination Using the mα-Tangent Method

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
R. Seshadri ◽  
M. M. Hossain
Keyword(s):  
Finite Element ◽  
Rapid Determination ◽  
Limit Load ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Limit Loads ◽  
Linear Elastic ◽  
Tangent Method ◽  
Mechanical Components

Limit load determination of mechanical components and structures by the mα-tangent method is proposed herein. The proposed technique is a simplified method that enables rapid determination of limit loads for a general class of mechanical components and structures. The method makes use of statically admissible stress field based on a linear elastic finite element analysis to estimate the limit loads. The method is applied to a number of mechanical component configurations and the results compare well with those obtained by the corresponding elastic-plastic finite element analyses results.

Limit Load Analysis of Cracked Components Using the Reference Volume Method

2006 ◽  
Vol 129 (3) ◽  
pp. 391-399 ◽  
Author(s):  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Elastic Modulus ◽  
Three Dimensional ◽  
Local Limit ◽  
Limit Load ◽  
Multiple Cracks ◽  
Element Analysis ◽  
Limit Loads ◽  
Integrity Assessment ◽  
Reference Volume ◽  
Volume Method

Cracks and flaws occur in mechanical components and structures, and can lead to catastrophic failures. Therefore, integrity assessment of components with defects is carried out. This paper describes the Elastic Modulus Adjustment Procedures (EMAP) employed herein to determine the limit load of components with cracks or crack-like flaw. On the basis of linear elastic Finite Element Analysis (FEA), by specifying spatial variations in the elastic modulus, numerous sets of statically admissible and kinematically admissible distributions can be generated, to obtain lower and upper bounds limit loads. Due to the expected local plastic collapse, the reference volume concept is applied to identify the kinematically active and dead zones in the component. The Reference Volume Method is shown to yield a more accurate prediction of local limit loads. The limit load values are then compared with results obtained from inelastic FEA. The procedures are applied to a practical component with crack in order to verify their effectiveness in analyzing crack geometries. The analysis is then directed to geometries containing multiple cracks and three-dimensional defect in pressurized components.

Analytical and Numerical Studies of a Thick Anisotropic Multilayered Fiber-Reinforced Composite Pressure Vessel

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Isaiah Ramos ◽  
Young Ho Park ◽  
Jordan Ulibarri-Sanchez
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Structural Damage ◽  
Three Dimensional ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Analytical Results ◽  
Composite Pressure Vessel

In this paper, we developed an exact analytical 3D elasticity solution to investigate mechanical behavior of a thick multilayered anisotropic fiber-reinforced pressure vessel subjected to multiple mechanical loadings. This closed-form solution was implemented in a computer program, and analytical results were compared to finite element analysis (FEA) calculations. In order to predict through-thickness stresses accurately, three-dimensional finite element meshes were used in the FEA since shell meshes can only be used to predict in-plane strength. Three-dimensional FEA results are in excellent agreement with the analytical results. Finally, using the proposed analytical approach, we evaluated structural damage and failure conditions of the composite pressure vessel using the Tsai–Wu failure criteria and predicted a maximum burst pressure.

Analytical and 3D Finite Element Study of the Deflection of an Elastic Cantilever Bilayer Plate

2010 ◽  
Vol 78 (1) ◽  
Author(s):  
M. Chekchaki ◽  
V. Lazarus ◽  
J. Frelat
Keyword(s):  
Thin Films ◽  
Finite Element ◽  
Three Dimensional ◽  
Analytical Formula ◽  
Mechanical Stresses ◽  
Linear Elastic ◽  
Wide Range ◽  
Finite Element Calculations ◽  
Analytical Formulas ◽  
Three Dimensional Elasticity

The mechanical system considered is a bilayer cantilever plate. The substrate and the film are linear elastic. The film is subjected to isotropic uniform prestresses due for instance to volume variation associated with cooling, heating, or drying. This loading yields deflection of the plate. We recall Stoney’s analytical formula linking the total mechanical stresses to this deflection. We also derive a relationship between the prestresses and the deflection. We relax Stoney’s assumption of very thin films. The analytical formulas are derived by assuming that the stress and curvature states are uniform and biaxial. To quantify the validity of these assumptions, finite element calculations of the three-dimensional elasticity problem are performed for a wide range of plate geometries, Young’s and Poisson’s moduli. One purpose is to help any user of the formulas to estimate their accuracy. In particular, we show that for very thin films, both formulas written either on the total mechanical stresses or on the prestresses, are equivalent and accurate. The error associated with the misfit between our theorical study and numerical results are also presented. For thicker films, the observed deflection is satisfactorily reproduced by the expression involving the prestresses and not the total mechanical stresses.

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