Reference Stress Values for Toroidal Vessels Subjected to Uniform Internal Pressure

2004 ◽  
Author(s):  
Khosrow Zarrabi ◽  
Abheek Basu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Explicit Expression ◽  
The Finite Element Method ◽  
Creep Life ◽  
Reference Stress ◽  
Uniaxial Creep ◽  
Rupture Data ◽  
Internal Pressures

Using the finite element method, the paper presents an explicit expression for the reference stress of tube/pipe bends with various degrees of ovality that are subjected to uniform internal pressures. No such task has been accomplished before. The presented reference stress may be used in conjunction with the uniaxial creep rupture data to obtain the creep life of the bend.

The Accepting of Pipe Bends With Ovality and Thinning Using Finite Element Method

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
AR. Veerappan ◽  
S. Shanmugam ◽  
S. Soundrapandian
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Cross Sections ◽  
Pressure Ratio ◽  
Empirical Relationship ◽  
The Finite Element Method ◽  
Element Method

Thinning and ovality are commonly observed irregularities in pipe bends, which induce higher stress than perfectly circular cross sections. In this work, the stresses introduced in pipe bends with different ovalities and thinning for a particular internal pressure are calculated using the finite element method. The constant allowable pressure ratio for different ovalities and thinning is presented at different bend radii. The allowable pressure ratio increases, attains a maximum, and then decreases as the values of ovality and thinning are increased. An empirical relationship to determine the allowable pressure in terms of bend ratio, pipe ratio, percent thinning, and percent ovality is presented. The pipe ratio has a strong effect on the allowable pressure.

Investigation of API 8 Round Casing Connection Performance—Part I: Introduction and Method of Analysis

1984 ◽  
Vol 106 (1) ◽  
pp. 130-136 ◽  
Author(s):  
W. T. Asbill ◽  
P. D. Pattillo ◽  
W. M. Rogers
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Mechanical Behavior ◽  
Experimental Analysis ◽  
Strain Gages ◽  
The Finite Element Method ◽  
Strength Of Materials ◽  
Methods Of Analysis ◽  
Element Method

The purpose of this investigation was to gain a better understanding into the mechanical behavior of the API 8 Round casing connection, when subjected to service loads of assembly interference, tension and internal pressure. The connection must provide both structural and sealing functions and these functions were evaluated by several methods. Part I discusses the methods of analysis, which include hand calculations using strength of materials, finite element method via unthreaded and threaded models, and experimental analysis using strain gages. Comparisons of all three methods are made for stresses and show that the finite element method accurately models connection behavior.

Reliability Analysis of Wear Casing Internal Pressure Strength

2013 ◽  
Vol 652-654 ◽  
pp. 1362-1366 ◽  
Author(s):  
Xian Yong Zhang ◽  
Jin Feng
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Monte Carlo ◽  
Internal Pressure ◽  
Reliability Analysis ◽  
Safety Evaluation ◽  
Steel Grade ◽  
Wear Depth ◽  
P110 Steel ◽  
Internal Pressures

Reliability of eccentric wear casing was studied by Monte-Carlo and finite element method. In different internal pressures, calculated reliability of P110 steel grade 9 5/8 inches casing with wear depth less than 0.5 times wall thickness. The influence of different cement ring circumferential missing amount and stratum pressures on wear casing reliability were presented. The results provide basis for casing safety evaluation and reasonable replacement.

Design of Hyper Compressor Packing Cup Rings for Optimum Fatigue Life

2006 ◽  
Author(s):  
E. H. Perez ◽  
S. Diab ◽  
R. D. Dixon
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Life ◽  
The Finite Element Method ◽  
Interference Fit ◽  
Analysis Methodology ◽  
Asme Code ◽  
Section Viii ◽  
Internal Pressures ◽  
Compressor Packing

Fatigue analyses of the inner and outer rings of hyper compressor retainers were performed to determine the optimum interference fit and interference fit diameter to maximize the fatigue life of both the inner and outer rings when subjected to cyclic operating internal pressures. The relationships between the optimum interference fit diameter, the amount of interference and cyclic pressures are derived using the fatigue analysis methodology of the ASME Code, Section VIII, Division 3. The effect of axial preload is evaluated, and the results are checked using the finite element method.

Axisymmetrical FEM Analysis and Estimation of the Sealing Performance in Pipe Flange Connections Combining Metallic Gasket With Adhesive Subjected to Internal Pressure and Temperature Change

2002 ◽  
Author(s):  
Masahide Katsuo ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Temperature ◽  
Internal Pressure ◽  
Temperature Change ◽  
Fem Analysis ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Sealing Performance ◽  
Moderately High Temperature

This study deals with the stress analysis and the estimation of the sealing performance of the pipe flange connections combining a metallic gasket with an adhesive subjected to an internal pressure and a temperature change. Stress distributions at the interface between the adherends and the adhesive in the connections are analyzed by using the finite element method (FEM). From the numerical calculations, the following results are obtained: (1) the stress distributes uniformly at the interface except near the edges, (2) the stress increases as Young’s modulus of an adhesive decreases, (3) the stress becomes singular at the edges of the interfaces. In the experiments, the pipe flange connections consisting of dissimilar circular gaskets with an adhesive were manufactured, and the leakage tests of the connections were carried out by applying an internal pressure and a temperature change to the connections. From the experimental results, the following results were obtained: (1) the sealing performance increased as the width of a gasket decreased and the initial clamping stress increased, and (2) the sealing performance of the pipe flange connections subjected to a temperature change increased under a moderately high temperature.

FEM Stress Analysis and an Evaluation of the Sealing Performance in Non-Circular Flange Connections With Gaskets Subjected to Internal Pressure

2006 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Ryo Kurosawa ◽  
Wataru Maezaki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Bolt Preload ◽  
Sealing Performance ◽  
The Difference

The contact gasket stress distributions of a non-circular flange connection with a compressed sheet gasket subjected to internal pressure were analyzed taking into account of the hysteresis behavior of the gasket by using the finite element method (FEM). Leakage tests were also conducted using an actual non-circular flange connection with a compressed sheet gasket under internal pressure. Using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. The difference in the new gasket constants between the values obtained from the present study and those by the PVRC procedure was substantial. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated.

Calculation of Residual Stresses in Plastic Deformation Processes

1973 ◽  
Vol 95 (1) ◽  
pp. 283-291 ◽  
Author(s):  
C. H. Lee ◽  
H. Iwasaki ◽  
S. Kobayashi
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Internal Pressure ◽  
Solid Cylinder ◽  
The Finite Element Method ◽  
Concentric Cylinders ◽  
Deformation Processes ◽  
Element Method

Three problems, namely, autofrettage process, plastic upsetting of a solid cylinder, and plane-strain and axisymmetric extrusion, are treated for residual stress calculation. A thick-walled cylinder consisting of two loosely fitted concentric cylinders of different materials is subjected to various levels of internal pressure. The residual stresses were calculated with an emphasis on the case where the inner surface of the cylinder yields again upon removal of the internal pressure. Comparison between the calculations and the measurements is given. The residual stresses in plastic upsetting of a solid cylinder were calculated by the finite-element method. An attempt was also made to simulate the real situation in extrusion by the finite-element method. An estimation of the residual stress distribution is then discussed for axisymmetric extrusion problems.

Finite Element Stress Analysis and Estimation of the Sealing Performance in Pipe Fittings With PTFE Tape for Threaded Connections Under Internal Pressure

2004 ◽  
Author(s):  
Mitsutoshi Ishimura ◽  
Masahide Katsuo ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Finite Element Stress Analysis ◽  
Leakage Test ◽  
Threaded Connections ◽  
Sealing Performance ◽  
Pipe Fittings

The interface stress distributions between the unsintered PTFE (Polytetrafluoroethlene) tape and threads of the fittings under an internal pressure are analyzed by using the finite element method (FEM). From the numerical calculations, the following results were obtained: (1) the stress distributes uniformly at the interface except near the edges, (2) the stress becomes singular at the edges of the interfaces and (3) the stress increases as the Young’s modulus of the PTFE tape thickness increases. The experiment of the leakage test of the connections consist of the socket and the plug manufactured of cast iron or stainless steel, which was also carried out by applying an internal oil pressure to the threaded connections. From the experiments, the following results are obtained: (1) the sealing performance in pipe fittings with PTFE tape increased as the number of turns in the PTFE tape increased, and it was not proportional to the numbers of turns, and (2) also as the number of turns in the screw plug increased, and it became a quadratic form, (3) the flow rate of leakage oil from the fittings under the internal pressure decreased as the number of turns in the screw plug increased, and (4) it could be estimated by using the Darcy-Weisbach and the Hagen-Poiseuille equations in the laminar-flow.

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