Thermal Sleeve Design For Pressure Vessels

1973 ◽  
Vol 2 (4) ◽  
pp. 229-234
Author(s):  
S. Venkatasubbu ◽  
P. Desrochers ◽  
C. N. Baronet
Keyword(s):  
Thin Shell ◽  
Welded Joint ◽  
Pressure Vessels ◽  
Transient Temperature ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Thermal Boundary Conditions ◽  
Pipe Radius ◽  
Maximum Stresses ◽  
Unit Pressure

The maximum stresses induced at the welded joint between a tube carrying a hot fluid and a vessel wall can be reduced by welding a thermal sleeve between them. The design stresses far various combinations of the sleeve and the tube of different mean pipe radius/thickness (R/t) ratios are presented independently for unit pressure and unit temperature of the fluid. The thermo-elastic methods used involved thick and thin shell analyses depending on the R/t ratio of the sleeve. The finite element method was used for the solution of the transient temperature and stress distributions. An experimental investigation was carried out to verify thermal boundary conditions and stress distribution.

A Simple Estimating Method for Reduction of Welding Residual Stresses in Thick Welded Joint From Stress-Relief Annealing—Part I: Development of the Analytical Method for Relaxation Tests and Its Applicability

1996 ◽  
Vol 118 (3) ◽  
pp. 343-350 ◽  
Author(s):  
K. Nakacho ◽  
Y. Ueda
Keyword(s):  
Stress State ◽  
Residual Stresses ◽  
Welded Joint ◽  
Uniaxial Stress ◽  
Stress Relief ◽  
Pressure Vessels ◽  
The Finite Element Method ◽  
Hand Calculation ◽  
Analytical Result ◽  
Good Coincidence

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of very thick welded joint by SR treatment. In this first report, an estimating method is developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon is very similar to that observed in the SR treatment of a joint. Using the various relations between stress and strains in the relaxation tests, estimating equations are formulated in order to simply calculate the change of the stress. The results obtained by applying the equations are compared with the highly accurate analytical result based on the finite element method. Both results show such a good coincidence that the appropriateness of the adopted method is confirmed. In the next report, this method is extended to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex.

Contact Between Vessel Shell and Welded Pad in Nozzle Reinforcement

1993 ◽  
Vol 115 (4) ◽  
pp. 364-372 ◽  
Author(s):  
H. Chen ◽  
Y.-J. Chao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Contact Force ◽  
Thin Shell ◽  
Pressure Vessels ◽  
The Finite Element Method ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Shell Analysis

In the thin shell analysis of welded pad reinforced nozzles in pressure vessels, no contact between pad and vessel is often assumed. The significance of this contact force to the stress distribution in the structure is little known. In this paper, stress results from the finite element analysis, which includes the contact force between the pad and the vessel, are reported. A comparison of the finite element results with those from thin shell analysis and experiments shows that the finite element method with contact assumption yields improved theoretical prediction for the stress distribution. The effect of both the gap and friction between the pad and the vessel are also investigated.

Thermal Stress Analysis for Air Inlet Part of Ramjet

2005 ◽  
Vol 297-300 ◽  
pp. 2253-2260 ◽  
Author(s):  
Song Heo Koo ◽  
Young Shin Lee ◽  
Jae Hoon Kim ◽  
S.J. Kim ◽  
Young Jin Choi
Keyword(s):  
Thermal Stress ◽  
Structural Design ◽  
Transient Temperature ◽  
Preliminary Design ◽  
Thermal Coefficient ◽  
The Finite Element Method ◽  
Thermal Boundary Conditions ◽  
Thermal Expansion Coefficients ◽  
Air Inlet ◽  
Expansion Coefficients

The purpose of this study is to estimate structural characteristic for air inlet part of ramjet in condition of flight at 12-15km height. Because air inlet part of ramjet is heated up to 700oK, high temperature properties such as Young’s modulus, thermal expansion coefficients and thermal conductivity coefficients are applied to the analysis. The analysis of transient temperature and thermal stress was performed by the finite element method with nonlinear code ABAQUS. The analysis was performed using several thermal coefficient and material properties to select preliminary design model for flight condition. Thermal boundary conditions were applied at ramjet inlet part until 0.01sec. The results of the analysis recommend tendency of thermal stress and temperature distribution. These are useful to select the structural material and to determine shape of air inlet part which satisfy the structural design safety.

A Simple Estimating Method for Reduction of Welding Residual Stresses in Thick Welded Joint From Stress-Relief Annealing—Part II: The Characteristics of Reduction of Welding Residual Stresses in Very Thick Joints During SR Treatment

1999 ◽  
Vol 121 (1) ◽  
pp. 11-16 ◽  
Author(s):  
K. Nakacho ◽  
Y. Ueda
Keyword(s):  
Stress State ◽  
Residual Stresses ◽  
Welded Joint ◽  
Uniaxial Stress ◽  
Stress Relief ◽  
Pressure Vessels ◽  
The Finite Element Method ◽  
Creep Theory ◽  
Multiaxial Stress State ◽  
Further Development

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of very thick welded joint by SR treatment. In the first report, an estimating method was developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon is considerably similar to that observed in the SR treatment of a joint. In this report, the stresses relaxed by SR treatment in a very thick welded joint are analyzed accurately by the finite element method based on thermal elastic-plastic-creep theory. The characteristics of the changes of the welding residual stresses in multiaxial stress state are studied in detail for further development of the estimating method to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex.

An Analysis of Thermal Cracking of Carbide Tools in Intermittent Cutting

1979 ◽  
Vol 101 (2) ◽  
pp. 159-164 ◽  
Author(s):  
H. Wu ◽  
J. E. Mayer
Keyword(s):  
Thermal Stress ◽  
Material Properties ◽  
Thermal Loading ◽  
Tool Material ◽  
Thermal Cracking ◽  
Transient Temperature ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Wave Type ◽  
Intermittent Cutting

This paper re-examines the problem of thermal cracking of carbide tools during intermittent cutting. In the paper a two-dimensional tool model is presented. A square-wave type of heat flux is assumed in the model to simulate the thermal loading of the tool during the cutting and non-cutting cycle. The transient temperature and thermal stress distributions of the tools are obtained by the finite element method. Two examples are considered in the paper to illustrate the procedures. It is found that tensile stress near the cutting edge and strong compressive thermal stress may exist in the tool respectively at different cutting cycles. Their magnitudes depend upon the tool material properties and the cutting conditions.

Thermal Stresses in a Submerged-Arc Welded Joint Considering Phase Transformations

1978 ◽  
Vol 100 (4) ◽  
pp. 356-362 ◽  
Author(s):  
B. A. B. Andersson
Keyword(s):  
Arc Welding ◽  
Thermal Stresses ◽  
Welded Joint ◽  
Stress Pattern ◽  
Transient Temperature ◽  
Fe Model ◽  
Two Dimensional ◽  
Stress Distributions ◽  
Transient Stress ◽  
Submerged Arc

Transient temperature and stress distributions are analytically and experimentally investigated for a butt welded plate of HT36-steel. A two-dimensional thermal FE-model is shown to represent the temperature distribution sufficiently well in a considered case of submerged-arc welding where a high welding speed is used. A two-dimensional mechanical FE-model is used to find the transient stress pattern. The theoretically and experimentally obtained residual stress distributions show some discrepancies which are believed to be due to Bauschinger effects not considered here.

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.

Design Formulas of Blind End Closures for High Pressure Vessels

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
R. D. Dixon ◽  
E. H. Perez
Keyword(s):  
High Pressure ◽  
Fatigue Life ◽  
Maximum Stress ◽  
Accurate Determination ◽  
Pressure Vessels ◽  
Stress Distributions ◽  
Fatigue And Fracture ◽  
Asme Code ◽  
Section Viii

The available design formulas for flat heads and blind end closures in the ASME Code, Section VIII, Divisions 1 and 2 are based on bending theory and do not apply to the design of thick flat heads used in the design of high pressure vessels. This paper presents new design formulas for thickness requirements and determination of peak stresses and stress distributions for fatigue and fracture mechanics analyses in thick blind ends. The use of these proposed design formulas provide a more accurate determination of the required thickness and fatigue life of blind ends. The proposed design formulas are given in terms of the yield strength of the material and address the fatigue strength at the location of the maximum stress concentration factor. Introduction of these new formulas in a nonmandatory appendix of Section VIII, Division 3 is recommended after committee approval.

scholarly journals Study of the influence of the foundation and the reservoir on the dynamic response in a concrete gravity dam profile

2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Iarly Vanderlei da Silveira ◽  
Lineu José Pedroso ◽  
Giuliano Santa Marotta
Keyword(s):  
Natural Frequencies ◽  
Free Vibration Analysis ◽  
Coupled System ◽  
Seismic Excitation ◽  
The Finite Element Method ◽  
Concrete Gravity Dam ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Ansys Apdl ◽  
Maximum Stresses

abstract: This work aims to verify the influence of the foundation and the reservoir on the dynamic behavior of concrete gravity dams in terms of the natural frequencies, vibration modes for a free vibration analysis; and in terms of maximum displacements and maximum stresses at singular points of the structure for a seismic excitation. The dam-reservoir-foundation interaction was investigated through modal and transient analysis by the finite element method via ANSYS APDL software. For this study, we used a typical Brazilian dam profile and compatible data from a Brazilian earthquake for the seismic excitation. The results showed the influence of the reservoir and the foundation on the natural frequencies in the coupled system, as well as its repercussions on the response of the dam under seismic excitation.

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