Stress Field Around a Large Opening in a Pressure Vessel During a Major Repair

2009 ◽  
Author(s):  
Erik Garrido ◽  
Euro Casanova
Keyword(s):  
Pressure Vessel ◽  
New Technologies ◽  
Mechanical Design ◽  
General Purpose ◽  
Pressure Vessels ◽  
Mechanical Equipment ◽  
Stress Distributions ◽  
Large Opening ◽  
Von Mises ◽  
Case Basis

It is a regular practice in the oil industry to modify mechanical equipment to incorporate new technologies and to optimize production. In the case of pressure vessels, it is occasionally required to cut large openings in their walls in order to have access to the interior part of the equipment for executing modifications. This cutting process produces temporary loads, which were obviously not considered in the original mechanical design. Up to now, there is not a general purpose specification for approaching the assessments of stress levels once a large opening in a vertical pressure vessel has been made. Therefore stress distributions around large openings are analyzed on a case-by-case basis without a reference scheme. This work studies the distribution of the von Mises equivalent stresses around a large opening in FCC Regenerators during internal cyclone replacement, which is a frequently required practice for this kind of equipment. A finite element parametric model was developed in ANSYS, and both numerical results and illustrating figures are presented.

Elastic Analysis of Journal Bearings

Volume 1 ◽  
2004 ◽  
Author(s):  
M. M. Villar ◽  
M. M. Pe´rez
Keyword(s):  
Stress Distribution ◽  
General Purpose ◽  
Von Mises Stress ◽  
Elastic Analysis ◽  
Stress Distributions ◽  
Finite Element Program ◽  
Relative Significance ◽  
Element Program ◽  
Von Mises ◽  
Hoop Stresses

In this paper a numerical model is used to investigate the effect of the elasticity of the bearing in the pressure distribution in the lubricant and the stress distribution in the bearing. The lubricant film, as well as a bearing, including the lining and the backing of the insert, and the housing, are modeled using the general-purpose ANSYS®5.7 commercial Finite Element program. Results have been obtained for the pressure, radial displacement, hoop and von Mises stress distributions at the surface of the bearing, as well as for the shear stress distribution at the interface between the lining and the backing. A number of conclusions have been drawn regarding the relative significance of the steep pressure gradient at the end of the lubricated region on the hoop stresses that cause localized bending distortions at the surface of the lining. These localized bending distortions, in turn, are likely to cause fatigue failure of the lining.

Dimensioning of thick-walled spherical and cylindrical pressure vessels

2017 ◽  
Vol 25 (7) ◽  
pp. 1405-1415 ◽  
Author(s):  
Patrick Schneider ◽  
Reinhold Kienzler
Keyword(s):  
Hoop Stress ◽  
Classical Problem ◽  
Pressure Vessels ◽  
Combined Loading ◽  
Von Mises Stress ◽  
Absolute Maximum ◽  
Stress Distributions ◽  
Extensive Discussion ◽  
Maximum Hoop Stress ◽  
Von Mises

In this contribution, we revisit the rather classical problem of Lamé and provide a novel and easy way to plot the stress distributions and the overall absolute maximum von Mises stress for arbitrary parameters in only two diagrams. We also provide a maximum hoop stress formula for combined loading and an extensive discussion covering the accuracy of dimensioning via the maximum hoop stress instead of the maximum von Mises stress, as well as the accuracy of the classical approximative hoop stress formulas.

Estimation of the Stresses in Rotational Autofrettage of Thick-Walled Pressure Vessels Using von Mises Yield Criterion

2021 ◽  
Author(s):  
S. M. Kamal ◽  
Faruque Aziz
Keyword(s):  
Plane Strain ◽  
Yield Criterion ◽  
Pressure Vessels ◽  
Flow Rule ◽  
Stress Distributions ◽  
Von Mises Yield Criterion ◽  
Potential Methods ◽  
Von Mises ◽  
Associated Flow Rule ◽  
Theoretical Analyses

Abstract Rotational autofrettage is one of the recently proposed potential methods for eliminating the in-service yielding of thick-walled cylindrical pressure vessels. A few researchers have studied the feasibility of the process theoretically, and asserted certain advantages over the practicing hydraulic and swage autofrettage processes. In the literature, all theoretical analyses on the rotational autofrettage are based on the Tresca yield criterion and its associated flow rule, along with the assumption of different plane end conditions (plane strain and generalized plane strain). In this paper, an analysis of the rotational autofrettage of cylindrical vessel is attempted incorporating von Mises yield criterion. The plane strain condition is used for the analysis. A numerical shooting method is used to solve the governing differential equations providing the elastic-plastic stress distributions in the cylinder during loading. The present procedure is numerically experimented for a typical AH36 pressure vessel. It is found that the achievable level of the maximum stress pressure of the rotationally autofrettaged vessel is 74.46% higher than that of its non-autofrettaged counterpart for an overstrain level of 46.7%.

Design Research on Pressure Vessel of Automobiles Assembly Shop

2014 ◽  
Vol 508 ◽  
pp. 204-207
Author(s):  
Yan Dong Song
Keyword(s):  
Research And Development ◽  
Early Warning ◽  
Pressure Vessel ◽  
Design Research ◽  
Pressure Vessels ◽  
Design System ◽  
Mechanical Equipment ◽  
Correct Evaluation ◽  
Modern Design ◽  
Assembly Shop

In the same conditions, the accidents of pressure vessel are much higher than other mechanical equipment. Therefore, the study on the pressure vessels in anomaly conditions and the dynamic response and tolerance capabilities of the structure not only helps to the research and development of warning surveillance and prevention technology about pressure vessels in anomaly conditions, but also contribute to the correct evaluation of the feasibility and reliability on the device of early warning monitoring system and the prevent technology. As pressure vessel is widely used and efficiency is enhanced, traditional failure analysis is restricted to test, analyze accidents, find out failure reasons and table proposals. It is realistic to make a modern design system for pressure vessels, judge failure reasons rapidly and table proposals. Keywords: pressure vessel; modern design; working characteristics

Study on the Structural Safety Evaluation for Pressure Vessel of the CNG Vehicle Using F.E.M.

2012 ◽  
Vol 569 ◽  
pp. 598-602 ◽  
Author(s):  
Eui Soo Kim ◽  
Jong Hyuk Kim ◽  
Byung Sun Moon ◽  
Jae Mo Goh
Keyword(s):  
Pressure Vessel ◽  
Storage Tank ◽  
Safety Management ◽  
Yield Criterion ◽  
Safety Evaluation ◽  
Pressure Vessels ◽  
Structural Safety ◽  
Test Procedures ◽  
Design Variables ◽  
Von Mises

CNG vehicles have to be equipped with a safe and reliable storage tank, such as composite pressure vessels, since the failure of the CNG storage tank induces fatal damages to passengers. In this research, the cause of vessel facture is investigated through formal inspection and engineering test procedures. Specifically, the composite pressure vessel design will be validated using the finite element method. In order to validate values of the optimal design variables in accordance with standard of the high pressure gas safety management, we used safety probability such as Von-Mises yield criterion, Tsai-Hill theory and stress ratio.

scholarly journals Thermo-Mechanical Autofrettage Process of Spherical Vessel

2020 ◽  
Vol 9 (3) ◽  
pp. 1109-1114
Keyword(s):  
Stress Distribution ◽  
Pressure Vessel ◽  
Mechanical Load ◽  
Pressure Vessels ◽  
Stress Distributions ◽  
Spherical Vessel ◽  
Yield Criteria ◽  
Elastic Plastic ◽  
Spherical Pressure ◽  
Plastic Stress

In this analysis results of Elastic-plastic stress distributions in a spherical pressure vessel with ThermoMechanical loads are discussed. Results of study are obtained with Finite element (FE) analysis. A quarter of pressure vessel is considered and modeled with all realistic details. In addition to presenting the stress distribution of the pressure vessel, in this work the effects thermo-Mechanical autofrettage on different limit strength for spherical pressure vessels are investigated. The effect of changing the load and various geometric parameters is investigated. Consequently, it can be observed that to be the significant differences between the present thermo-Mechanical autofrettage and earlier (Mechanical autofrettage and Thermal autofrettage) method of autofrettage for the predictions of Elastic-plastic stress distributions of spherical pressure vessels. Some realistic examples are considered and results are obtained for the whole vessel by applying thermal load and mechanical load. The actual material curve is used for loading, unloading and residual stress behavior of spherical pressure vessel. Kinematic hardening material is considered and effect of Bauschinger effect factors are studied with thermo-mechanical load. Equivalent Von -Mises yield criteria is used for yield criteria. Behavior of elastic-perfectly plastic is also studied and compared. Influence of Thermo-Mechanical autofrettage over stress distribution and load bearing capacity of spherical vessel is examined. The question of whether Thermo-mechanical autofrettage gives more favorable residual compressive stress distribution and therefore extension of pressure vessel life is investigated in this analysis.

Influence Coefficients and Pressure Vessel Analysis

1960 ◽  
Vol 82 (3) ◽  
pp. 259-267 ◽  
Author(s):  
G. D. Galletly
Keyword(s):  
Pressure Vessel ◽  
Shell Theory ◽  
Pressure Vessels ◽  
Toroidal Shell ◽  
Stress Distributions ◽  
Specialized Knowledge ◽  
Influence Coefficients ◽  
Final Stress ◽  
Bending Stresses ◽  
Accurate Stress

A description is given of the utility of influence coefficients for analyzing pressure vessels. To illustrate their advantages two relatively complex problems were selected and their final stress distributions calculated. The problems were (i) a cylinder closed by a torispherical head and (ii) a cylinder joined to a smaller cylinder by an ellipsoidal-toroidal shell. Two vessels were analyzed using influence coefficients which have recently become available. It is shown that accurate stress distributions can be obtained quickly and that a specialized knowledge of shell theory is not required. The method also shows the distribution of bending stresses throughout the shells. These latter, which can be important, are usually ignored by the various codes.

SAE 1025

Alloy Digest ◽  
1987 ◽  
Vol 36 (9) ◽  
Keyword(s):  
Fracture Toughness ◽  
Carbon Steel ◽  
Heat Treating ◽  
Plain Carbon Steel ◽  
General Purpose ◽  
Pressure Vessels ◽  
Permanent Mold ◽  
Steel Mills ◽  
Cold Worked ◽  
Permanent Mold Castings

Abstract SAE 1025 is a plain carbon steel for general-purpose construction and engineering. It is used in the hot-worked, cold-worked, normalized or water-quenched-and-tempered condition. It also is carburized and used for case-hardened parts. Its many uses include bolts, forgings, axles, machinery components, cold-extruded parts, pressure vessels, case-hardened parts, chain and sprocket assemblies, spinning tools and permanent-mold castings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-114. Producer or source: Carbon steel mills.

Effect of Carbide Content on Temper Embrittlement of 2.25Cr1Mo Steel

2016 ◽  
Author(s):  
Yian Wang ◽  
Guoshan Xie ◽  
Zheng Zhang ◽  
Xiaolong Qian ◽  
Yufeng Zhou ◽  
...  
Keyword(s):  
High Temperature ◽  
Pressure Vessel ◽  
High Stress ◽  
Temper Embrittlement ◽  
Damage Mechanism ◽  
Pressure Vessels ◽  
Nondestructive Method ◽  
Operating Conditions ◽  
Low Alloy Steels ◽  
Carbide Content

Temper embrittlement is a common damage mechanism of pressure vessels in the chemical and petrochemical industry serviced in high temperature, which results in the reduction of roughness due to metallurgical change in some low alloy steels. Pressure vessels that are temper embrittled may be susceptible to brittle fracture under certain operating conditions which cause high stress by thermal gradients, e.g., during start-up and shutdown. 2.25Cr1-Mo steel is widely used to make hydrogenation reactor due to its superior combination of high mechanical strength, good weldability, excellent high temperature hydrogen attack (HTHA) and oxidation-resistance. However, 2.25Cr-1Mo steel is particularly susceptible to temper embrittlement. In this paper, the effect of carbide on temper embrittlement of 2.25Cr-1Mo steel was investigated. Mechanical properties and the ductile-brittle transition temperature (DBTT) of 2.25Cr-1Mo steel were measured by tensile test and impact test. The tests were performed at two positions (base metal and weld metal) and three states (original, step cooling treated and in-service for a hundred thousand hours). The content and distribution of carbides were analyzed by scanning electron microscope (SEM). The content of Cr and Mo elements in carbide was measured by energy dispersive X-ray analysis (EDS). The results showed that the embrittlement could increase the strength and reduce the plasticity. Higher carbide contents appear to be responsible for the higher DBTT. The in-service 2.25Cr-1Mo steel showed the highest DBTT and carbide content, followed by step cooling treated 2.25Cr-1Mo steel, while the as-received 2.25Cr-1Mo steel has the minimum DBTT and carbide content. At the same time, the Cr and Mo contents in carbide increased with the increasing of DBTT. It is well known that the specimen analyzed by SEM is very small in size, sampling SEM specimen is convenient and nondestructive to pressure vessel. Therefore, the relationship between DBTT and the content of carbide offers a feasible nondestructive method for quantitative measuring the temper embrittlement of 2.25Cr-1Mo steel pressure vessel.

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