Some Comments on the Stress Concentration and Shakedown Factors for Spherical Pressure Vessels with Flush Radial Cylindrical Nozzles

1979 ◽  
Vol 21 (3) ◽  
pp. 153-157 ◽  
Author(s):  
M. Robinson
Keyword(s):  
Stress Concentration ◽  
Experimental Work ◽  
Stress Concentration Factor ◽  
Thin Shell ◽  
Shell Theory ◽  
Pressure Vessels ◽  
Simple Design ◽  
Design Proposal ◽  
Thin Shell Theory ◽  
Spherical Pressure

Some previous theoretical shakedown pressures for a cylinder—sphere vessel under internal pressure are, for a certain range of parameters, shown to be too high. The error can be traced to an underestimate of the stress concentration factor owing to the use of the centreline thin-shell theory and the neglect of cylinder stresses. It is shown that much more theoretical and experimental work needs to be done to establish reliable shakedown pressures for a comprehensive range of parameters. A simple design proposal is suggested which should meanwhile prove adequate.

Some Observations on the Design of Spherical Pressure Vessels with Flush Cylindrical Nozzles

1965 ◽  
Vol 180 (1) ◽  
pp. 497-512 ◽  
Author(s):  
F. A. Leckie ◽  
D. J. Payne
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Pressure Vessel ◽  
Concentration Factor ◽  
Pressure Vessels ◽  
Compact Form ◽  
Cylindrical Nozzle ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Spherical Pressure

In this paper the design of a spherical pressure vessel pierced by a radial cylindrical nozzle is discussed. The nozzles considered end flush with the inside of the vessel. Previous work on stress concentration factors, shakedown factors and limit pressure factors has been drawn together and presented in a compact form convenient for the use of designers. These results have been used to discuss the implications of designing to a certain stress concentration factor and to show that this procedure is very reasonable when a concentration factor of 2.25 is used.

Shell Solution for Reinforced Cylinder to Sphere Intersection

1988 ◽  
Vol 110 (1) ◽  
pp. 64-69 ◽  
Author(s):  
G. N. Brooks
Keyword(s):  
Exact Solution ◽  
Thin Shell ◽  
Thermal Loading ◽  
Shell Theory ◽  
Computer Code ◽  
Cylindrical Vessel ◽  
Closed Form Solutions ◽  
Thin Shell Theory ◽  
Insert Plate ◽  
Spherical Pressure

To reduce the stress level at nozzle to spherical pressure vessel intersections, reinforcement is generally added to the sphere, the nozzle or both. This paper describes the development of a computer code using closed-form solutions to analyze this problem. Up to seven components can be considered in the model: inner and outer nozzles each connected to pipes; an insert plate; spherical shell; and cylindrical vessel connected to the sphere. All three forces and moments on each nozzle as well as internal pressure and simple thermal loading are considered. Thin shell theory is used for each component. Due to the complexity of the exact solution for the sphere, asymptotic solutions valid for both the shallow and steep regions are used. This solution allows parameter studies to be performed efficiently for various reinforcement geometries.

Turbulence-Induced Vibration Analysis of an Open Curved Thin Shell

2010 ◽  
Author(s):  
Mitra Esmailzadeh ◽  
Aouni A. Lakis
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Root Mean Square ◽  
Thin Shell ◽  
Shell Theory ◽  
Pressure Field ◽  
Mean Square Displacement ◽  
Mean Square ◽  
Cross Spectral Density ◽  
Thin Shell Theory

A method is presented to predict the root mean square displacement response of an open curved thin shell structure subjected to a turbulent boundary-layer-induced random pressure field. The basic formulation of the dynamic problem is an efficient approach combining classic thin shell theory and the finite element method. The displacement functions are derived from Sanders’ thin shell theory. A numerical approach is proposed to obtain the total root mean square displacements of the structure in terms of the cross-spectral density of random pressure fields. The cross-spectral density of pressure fluctuations in the turbulent pressure field is described using the Corcos formulation. Exact integrations over surface and frequency lead to an expression for the total root mean square displacement response in terms of the characteristics of the structure and flow. An in-house program based on the presented method was developed. The total root mean square displacements of a curved thin blade subjected to turbulent boundary layers were calculated and illustrated as a function of free stream velocity and damping ratio. A numerical implementation for the vibration of a cylinder excited by fully developed turbulent boundary layer flow was presented. The results compared favorably with those obtained using software developed by Lakis et al.

Design-Focused Stress Analysis of Cylindrical Pressure Vessels Intersected by Small-Diameter Nozzles

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Faisal M. Mukhtar ◽  
Husain J. Al-Gahtani
Keyword(s):  
Shell Theory ◽  
Large Diameter ◽  
Small Diameter ◽  
Vessel Diameter ◽  
Theory Of Elasticity ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Overall Design ◽  
Design Charts ◽  
Thin Shell Theory

In a related work previously carried out by the authors, finite element analysis of cylindrical vessel–cylindrical nozzle juncture based on the use of thin shell theory, due to the fact that the intersecting nozzle sizes are moderate to large, have been presented. Such analysis becomes invalid in cases when the nozzles are small in sizes which may result in nozzles whose configuration violates the validity of shell assumption. As a result, use of solid elements (based on theory of elasticity) in modeling the cylindrical vessels with small-diameter nozzles is presented in the present paper. Discussions of the numerical experiments and the results achieved are, first, given. The results are then compared with the prediction by other models reported in the literature. In order to arrive at the overall design charts that cover all the possible ranges of nozzle-to-vessel diameter ratio, the charts for the vessels with moderate-to-large-diameter nozzles are augmented with those of cylindrical vessels intersected by small-diameter nozzles developed in this work.

Effect of Blend Radius on Stress Concentration Factor of Crossbored Holes in Thick Walled Pressure Vessels

2003 ◽  
Author(s):  
Daniel T. Peters
Keyword(s):  
Stress Concentration ◽  
Detailed Analysis ◽  
Computer Technology ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Pressure Vessels ◽  
Stress Concentrations ◽  
The Past ◽  
Recent Developments ◽  
Fea Analysis

Many studies have been performed on the effect of stress concentration factor in thick walled cylinders caused by holes drilled to the wall perpendicular to the vessel ID, commonly called crossbores. Recent developments in FEA analysis and computer technology have allowed detailed analysis in their effect on the stresses in pressure vessels. This allows the reevaluation of many theories developed in the past. The following is a study of how applying a blend radius to the inside intersection of a vessel bore and a crossbore affects the stresses in vicinity of the hole and the stress concentrations developed near the hole.

A NEW KIND OF SINGULAR STIFF PROBLEMS AND APPLICATION TO THIN ELASTIC SHELLS

1995 ◽  
Vol 05 (01) ◽  
pp. 47-66 ◽  
Author(s):  
D. CAILLERIE ◽  
E. SANCHEZ-PALENCIA
Keyword(s):  
Asymptotic Behavior ◽  
Local Structure ◽  
Thin Shell ◽  
Spectral Properties ◽  
Shell Theory ◽  
Stiff Problems ◽  
Medium Frequency ◽  
Limit Solution ◽  
General Configuration ◽  
Thin Shell Theory

We consider the asymptotic behavior of the solution of a class of problems involving a small parameter ε and ε2. This generalizes the “singular stiff” problems arising in classical thin shell theory. The new problems appear in theory of composite shells, when the local structure implies coupling between membrane stresses and flexions. According to specific hypotheses, this kind of problems contains singular perturbations and penalty problems where the limit solution belongs to a subspace G1 of the general configuration space V. In addition to the coercive problem, spectral properties are considered in the small and medium frequency ranges, including spectral families in the case without compactness.

Free vibration of bi-material cylindrical shells

2016 ◽  
Vol 230 (15) ◽  
pp. 2637-2649 ◽  
Author(s):  
Saeed Sarkheil ◽  
Mahmud S Foumani ◽  
Hossein M Navazi
Keyword(s):  
Exact Solution ◽  
Cylindrical Shell ◽  
Free Vibration ◽  
Boundary Conditions ◽  
State Space ◽  
Thin Shell ◽  
Shell Theory ◽  
Circular Cylindrical Shell ◽  
Space Technique ◽  
Thin Shell Theory

Based on the Sanders thin shell theory, this paper presents an exact solution for the vibration of circular cylindrical shell made of two different materials. The shell is sub-divided into two segments and the state-space technique is employed to derive the homogenous differential equations. Then continuity conditions are applied where the material of the cylindrical shell changes. Shells with various combinations of end boundary conditions are analyzed by the proposed method. Finally, solving different examples, the effect of geometric parameters as well as BCs on the vibration of the bi-material shell is studied.

Vibration of Shallow Shells: A Review With Bibliography

1997 ◽  
Vol 50 (8) ◽  
pp. 431-444 ◽  
Author(s):  
K. M. Liew ◽  
C. W. Lim ◽  
S. Kitipornchai
Keyword(s):  
Thin Shell ◽  
Shell Theory ◽  
Free Vibration Analysis ◽  
Review Article ◽  
Shallow Shells ◽  
First Order ◽  
Recent Developments ◽  
Thick Shells ◽  
Thin Shell Theory ◽  
Introductory Review

This review article documents recent developments in the free vibration analysis of thin, moderately thick, and thick shallow shells. An introductory review of the studies in Kirchhoff-Love classical thin shell theory is given. The development of studies in moderately thick shells incorporating the effects of transverse shear deformation and rotary inertia is detailed. This review article mainly focuses on research advances in vibration studies since the 1970s using the classical Kirchhoff-Love, first-order, and higher-order theories. The validity and range of applicability of these theories are examined. There are 163 references listed at the end of the article.

scholarly journals Calculation method of locking torque based on elastic thin shell theory for hydraulic locking sleeve

2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769269
Author(s):  
Ming Yan ◽  
Hai-Chao Liu
Keyword(s):  
Thin Shell ◽  
Shell Theory ◽  
Calculation Model ◽  
Thin Cylindrical Shell ◽  
Deformation Equation ◽  
Test Platform ◽  
Large Elastic Deformation ◽  
Five Axis ◽  
Thin Shell Theory ◽  
Rotational Freedom

The hydraulic locking sleeve is a key component of precision instruments such as five-axis machine tools, giant astronomical telescope, and satellite antenna. This is subjected to the action of pressure load causing large elastic deformation and locking the rotational freedom of feed shaft at any angle. The maximum locking torque is an important parameter for designing the hydraulic locking sleeve. First, the hydraulic locking sleeve is simplified as elastic thin cylindrical shell structure. Neglecting the bending and twisting effects, the calculation equations describing the deformation and stress state between the hydraulic locking sleeve and rotary shaft are derived by applying the theory of elastic thin shell. Then, taking into account that one end of the hydraulic lock sleeve is fixed to the shaft sleeve seat by the end face flange; the calculating formula of the maximum locking torque of the hydraulic locking sleeve is obtained by modifying the deformation equation based on moment model. Finally, a test platform of hydraulic locking sleeve is designed, which can measure the maximum locking torque of the hydraulic locking sleeve. The error between the calculation result of locking torque theoretical calculation model and the experimental measured value is <15%. As a result, the causes of the error are analyzed, and the effects of the shaft sleeve length, wall thickness, and radius on the maximum locking torque are calculated.

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