Bifurcation of Elastic-Plastic Circular Cylindrical Shells Under Internal Pressure

1979 ◽  
Vol 46 (4) ◽  
pp. 889-894 ◽  
Author(s):  
C.-C. Chu
Keyword(s):  
Internal Pressure ◽  
Critical Pressure ◽  
Separation Of Variables ◽  
Cylindrical Shells ◽  
Maximum Pressure ◽  
Thin Shells ◽  
The Finite Element Method ◽  
Elastic Plastic ◽  
Analytical Results ◽  
Good Agreement

The bifurcation of long elastic-plastic cylindrical shells subject to internal pressure is investigated. It is assumed that the end conditions are such that plane strain conditions prevail. For thin shells, simple approximate bifurcation criteria are obtained analytically. The finite-element method is then employed, in conjunction with separation of variables, to obtain the bifurcation conditions for cylindrical shells with arbitrary thickness to radius ratios. For sufficiently thin shells, the numerical and the analytical results are in good agreement for the critical pressure at bifurcation. The numerical and analytical results both indicate that, for sufficiently thin shells, a variety of bifurcation modes are available virtually simultaneously at this critical pressure. However, for thicker shells, the numerical results reveal that there is a single preferred bifurcation mode. The mode number associated with this preferred bifurcation mode depends on the thickness to radius ratio. The possibility of bifurcation occurring before the attainment of the maximum pressure is also explored. For the specific cases investigated here, bifurcation always occurs after the maximum pressure point.

Stress Analysis of Stainless Steel Elbow and Tee Fittings Subjected to Internal Pressure and External Loads

1999 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Tetsuya Furuya ◽  
Tadahiro Murakami ◽  
Yasuyuki Kagaya
Keyword(s):  
Internal Pressure ◽  
Wall Thickness ◽  
Bending Moment ◽  
Maximum Pressure ◽  
Screw Thread ◽  
The Finite Element Method ◽  
Internal Working ◽  
Stress States ◽  
Screw Threads ◽  
External Loads

Abstract In this paper, mechanical behaviors of the Elbow and Tee fittings connected to pipes by screw threads under internal pressure, external tensile loads and bending moment are analyzed using the Finite Element Method (FEM). FEM code employed is MARC. The maximum Mises stress of the Elbow and Tee fittings are obtained when the wall thickness is changed while the internal working maximum pressure is held constant at 20bar. The elasto-plastic stress states of screw threads the fittings and the pipes are obtained under internal pressure and external loads. Under the assumptions that nodal points are released when the strain of the elements reaches the rupture strain of the fitting’s material, the load when the rupture occurs at the screw thread is analyzed. The safety factor for the wall thickness of the Elbow and Tee fittings used in the experiment is found to be about 5. The results indicate deduced that the dimensions of Elbow and Tee fittings can be reduced. The strength of the fittings under internal pressure and external loads is obtained. It is found that the stress concentrates at the first root of male thread and expected that a fracture initiates at the first root. The strain of the Elbow and Tee fittings subjected to internal pressure were measured by using strain gauges. The numerical results are in a fairly good agreement with the experimental results.

Numerical Stress Analysis of Intersecting Cylindrical Shells

1993 ◽  
Vol 115 (3) ◽  
pp. 275-282 ◽  
Author(s):  
V. N. Skopinsky
Keyword(s):  
Internal Pressure ◽  
Stress Analysis ◽  
Elastic Stress ◽  
Cylindrical Shells ◽  
Numerical Approach ◽  
The Finite Element Method ◽  
Pressure Loading ◽  
Purpose Computer ◽  
Special Purpose Computer

This paper presents the numerical approach for the stress analysis of the intersecting shells. For a systematic study of this problem, the classification of the model joints is introduced. Stress analysis has been made with the application of the finite element method based on the modified mixed formulation. The developed special-purpose computer program SAIS is used for elastic stress analysis of the model joints of the intersecting shells. Comparison of the calculated and experimental results for ORNL-1 model are presented for internal pressure and moment loadings. The parametric study of the model joints of the intersecting cylindrical shells under internal pressure loading was performed. The presented results show the effects of changing various geometric and angular parameters on the maximum effective stresses in the shells.

scholarly journals Rotation, inversion and perversion in anisotropic elastic cylindrical tubes and membranes

2013 ◽  
Vol 469 (2153) ◽  
pp. 20130011 ◽  
Author(s):  
Alain Goriely ◽  
Michael Tabor
Keyword(s):  
Internal Pressure ◽  
Large Deformations ◽  
Axial Strain ◽  
Cylindrical Shells ◽  
Thin Shells ◽  
Structural Elements ◽  
Response Behaviour ◽  
Wide Range ◽  
Cylindrical Tubes ◽  
Anisotropic Elastic

Cylindrical tubes and membranes are universal structural elements found in biology and engineering over a wide range of scales. Working in the framework of nonlinear elasticity, we consider the possible deformations of elastic cylindrical shells reinforced by one or two families of fibres. We consider both small and large deformations and the reduction from thick cylindrical shells (tubes) to thin shells (cylindrical membranes). In particular, a number of universal parameter regimes can be identified where the response behaviour of the cylinder is qualitatively different. This include the possibility of inversion of twist or axial strain when the cylinder is subject to internal pressure.

Elastic-Plastic Buckling of Aluminum Cylindrical Shells Subjected to Axisymmetric Impulse Loads

1974 ◽  
Vol 41 (4) ◽  
pp. 985-988 ◽  
Author(s):  
D. L. Wesenberg
Keyword(s):  
Pulse Shaping ◽  
Pressure Pulse ◽  
Capacitor Bank ◽  
Cylindrical Shells ◽  
Computer Code ◽  
Plastic Buckling ◽  
Elastic Plastic ◽  
Fast Discharge ◽  
Circular Cylindrical Shells ◽  
Good Agreement

The elastic-plastic buckling of 6061-T4 aluminum, circular cylindrical shells is examined experimentally and analytically. Groups of shells with radius-to-thickness ratios of 100, 200, and 300 were loaded with short-duration axisymmetric pressure pulses. A fast-discharge capacitor bank and current pulse shaping technique are utilized to provide a sine-squared pressure pulse with duration of about 5 μsec, a duration sufficiently short that loading can be considered impulsive. Average peak-to-peak permanent buckling deformations and wave numbers are compared with predictions from a Lagrangian, finite-difference computer code, and good agreement is obtained between measurements and predictions.

FEM Stress Analysis and Sealing Performance in Bolted Flange Connections With Cover of Pressure Vessel Subjected to Internal Pressure

2004 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Rie Higuchi
Keyword(s):  
Internal Pressure ◽  
Pressure Vessel ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Pressure Application ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Bolted Flange ◽  
Good Agreement ◽  
Spiral Wound

The stresses of a bolted flange connection with a cover of pressure vessel (CPV) in which a spiral wound gasket is inserted, under internal pressure are analyzed taking account a hysteresis of the gasket using the finite element method (FEM). The leakage tests were also conducted for an actual bolted flange connection with a CPV and a spiral wound gasket. Using the calculated contact gasket stress distribution of the bolted flange connection with the CPV under internal pressure and the tightness parameter, the values of the new gasket constants were obtained by taking into account the changes in the contact gasket stress. A difference in the new gasket constants between the estimated values obtained from the actual bolted flange connection with the CPV and the values obtained by the PVRC procedure was small. In addition, a method to determine the bolt preload for a given tightness parameter was demonstrated. The obtained results of the bolt preload for the bolted flange connection with the CPV were in a fairly good agreement with those obtained by the PVRC procedure under a lower pressure application. However, a difference in the bolt preload was about 7% when the internal pressure was increased.

Thermal Behavior of Rectangular Flux Channels With Discretely Specified Contact Flux and Temperature

2015 ◽  
Author(s):  
Masood Razavi ◽  
Yuri S. Muzychka ◽  
Serpil Kocabiyik
Keyword(s):  
Boundary Conditions ◽  
Thermal Behavior ◽  
Least Squares Method ◽  
Separation Of Variables ◽  
Heat Fluxes ◽  
Fourier Series Expansion ◽  
The Finite Element Method ◽  
Commercial Software Package ◽  
Good Agreement

In this paper, an analytical solution for the thermal behavior of rectangular flux channels with discretely specified boundary conditions is presented. The boundary conditions along the source plane can be a combination of contact temperatures, heat fluxes, and/or adiabatic. Convective cooling is applied along the sink plane, and the edges of the channel are assumed adiabatic. The governing equation of the system is the Laplace equation which is solved using the method of separation of variables and the least squares method. The solution is presented in the form of Fourier series expansion. As a case study, a symmetrical flux channel with a combination of five discretely specified boundary conditions, including temperature, heat flux and adiabatic conditions is considered. Temperature profile along the channel is calculated and compared with the Finite Element Method (FEM) using COMSOL commercial software package [1]. A good agreement is observed between the analytical and FEM results.

An Improved Numerical Calculation Technique for Large Elastic-Plastic Transient Deformations of Thin Shells: Part 2—Evaluation and Applications

1971 ◽  
Vol 38 (2) ◽  
pp. 429-436 ◽  
Author(s):  
L. Morino ◽  
J. W. Leech ◽  
E. A. Witmer
Keyword(s):  
Numerical Calculation ◽  
Computational Efficiency ◽  
Large Deformations ◽  
Thin Shells ◽  
Theoretical Formulation ◽  
Elastic Plastic ◽  
Calculation Technique ◽  
Good Agreement

Based upon the theoretical formulation presented in Part 1 of this paper, improvements in accuracy and computational efficiency are realized. Comparisons of predictions with experimental transient large deformations and strains show good agreement.

Prediction of natural frequencies for thin circular cylindrical shells

2000 ◽  
Vol 214 (10) ◽  
pp. 1313-1328 ◽  
Author(s):  
M N Naeem ◽  
C B Sharma
Keyword(s):  
Variational Approach ◽  
Analytical Procedure ◽  
Natural Frequencies ◽  
Cylindrical Shells ◽  
Polynomial Functions ◽  
Simply Supported ◽  
Analytical Results ◽  
General Eigenvalue Problem ◽  
Circular Cylindrical Shells ◽  
Good Agreement

In this paper an analytical procedure is given to study the free-vibration characteristics of thin circular cylindrical shells. Ritz polynomial functions are assumed to model the axial modal dependence and the Rayleigh-Ritz variational approach is employed to formulate the general eigenvalue problem. Influence of some commonly used boundary conditions, viz. simply supported-simply supported, clamped-clamped and clamped-free, and also the effects of variations of shell parameters on the vibration frequencies are examined. Natural frequencies for a number of particular cases are evaluated and compared with some available experimental and other analytical results in the literature on this topic. These results are given in the form of tables and figures. A very good agreement between the results of the present analysis and the corresponding experimental and analytical results available in the literature is obtained to confirm the validity and accuracy as well as the efficiency of the method.

Stress Analysis and Determination of Bolt Preload in Pipe Flange Connections With Gaskets Under Internal Pressure

2002 ◽  
Vol 124 (4) ◽  
pp. 385-396 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Naofumi Ogata ◽  
Takahito Nishida
Keyword(s):  
Internal Pressure ◽  
Contact Stress ◽  
Theory Of Elasticity ◽  
The Finite Element Method ◽  
Flange Connection ◽  
Bolt Preload ◽  
Contact Stress Distribution ◽  
Good Agreement ◽  
Spiral Wound

The stresses of a pipe flange connection with a spiral-wound gasket under internal pressure are analyzed taking account a nonlinearity and a hysteresis of the gasket by using an axisymmetric theory of elasticity and the finite element method (FEM). The leakage tests were also conducted using an actual pipe flange connection with a spiral-wound gasket. Using the contact stress distribution of the pipe flange connection with 3-in. nominal diameter under internal pressure and the tightness parameter, the values of the new gasket constants are obtained by taking into account the changes in the contact stress. A difference in the new gasket constants between the estimated values obtained from the actual pipe flange connection and the values obtained by the PVRC procedure is small. In addition, a method to determine the bolt preload for a given tightness parameter is demonstrated. The obtained results of the bolt preload for the pipe flange connection are in a fairly good agreement with those obtained by the PVRC procedure under a lower pressure application. However, a difference in the bolt preload is about 10% when an internal pressure is increased.

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