Investigation on the Influence of Stiffener Size on the Buckling Pressures of Circular Cylindrical Shells Under Hydrostatic Pressure

1962 ◽  
Vol 6 (03) ◽  
pp. 24-32
Author(s):  
James A. Nott
Keyword(s):  
Cylindrical Shells ◽  
High Strength ◽  
Plastic Buckling ◽  
Theoretical Derivation ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Simple Support ◽  
Circular Cylindrical Shells ◽  
Support Conditions ◽  
Elastic Perfectly Plastic

A theoretical derivation is given for elastic and plastic buckling of stiffened, circular cylindrical shells under uniform external hydrostatic pressures. The theory accounts for variable shell stresses, as influenced by the circular stiffeners, and critical buckling pressures are obtained for simple support conditions at the shell-frame junctures. Collapse pressures for both elastic and plastic buckling are determined by iteration and numerical minimization. The theory is applicable to shells made either of strain-hardening or elastic-perfectly plastic materials. Using the developed analysis, it is shown that a variation in stiffener size can change the buckling pressures. Test data from high-strength steel and aluminum cylinders show agreement between the theoretical and experimental collapse pressures to within approximately six percent.

Buckling of Axially Compressed Circular Cylindrical Shells at Stresses Smaller Than the Classical Critical Value

1965 ◽  
Vol 32 (3) ◽  
pp. 542-546 ◽  
Author(s):  
N. J. Hoff ◽  
L. W. Rehfield
Keyword(s):  
Critical Stress ◽  
Cylindrical Shells ◽  
Bending Moment ◽  
Critical Value ◽  
Closed Form Solutions ◽  
Stress Resultant ◽  
Simple Support ◽  
Circumferential Displacement ◽  
Circular Cylindrical Shells ◽  
Support Conditions

Closed-form solutions are given of the linear Donnell equations defining the buckling of thin-walled circular cylindrical shells subjected to uniform axial compression. In addition to the classical simple support conditions requiring the vanishing of the radial displacement, the axial bending-moment resultant, the axial additional normal-stress resultant, and the circumferential displacement, three other, equally justifiable, simple support conditions are defined and studied in the case of the semi-infinite shell. Two of them yield buckling stresses amounting to about one half the classical critical stress.

Plastic Limit Loads for Piping Branch Junctions

2007 ◽  
Vol 345-346 ◽  
pp. 1377-1380 ◽  
Author(s):  
Yun Jae Kim ◽  
Kuk Hee Lee ◽  
Chi Yong Park
Keyword(s):  
Three Dimensional ◽  
Limit Load ◽  
Plastic Limit ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Wide Range ◽  
Pipe Radius ◽  
Plastic Limit Load ◽  
The Mean ◽  
Elastic Perfectly Plastic

The present work presents plastic limit load solutions for branch junctions under internal pressure and in-plane bending, based on detailed three-dimensional (3-D) FE limit analyses using elastic-perfectly plastic materials. The proposed solutions are valid for a wide range of branch junction geometries; ratios of the branch-to-run pipe radius and thickness from 0.0 to 1.0, and the mean radius-to-thickness ratio of the run pipe from 5.0 to 20.0.

scholarly journals Principal Stress Ratio Effect at Residual Stress Determination Utilizing the Variation of Indentation Hardness

Lubricants ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 50
Author(s):  
Per-Lennart Larsson
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Ratio ◽  
Experimental Situation ◽  
Indentation Hardness ◽  
Stress Determination ◽  
Residual Stress Determination ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Elastic Perfectly Plastic

The determination of residual stresses is an important issue when it comes to material failure analysis. The variation of global indentation properties, due to the presence of residual stresses, can serve as a guideline for the size and direction of such stresses. One of these global indentation properties, the material hardness, is unfortunately invariant of residual stresses when metals and alloys are at issue. In this situation, one has to rely on the size of the indentation contact area for residual stress determination. For other materials such as ceramics and polymers, where elastic deformations are of greater importance at indentation, such invariance is no longer present. Here, this variation is investigated based on finite element simulations. The aim is then to determine how the indentation hardness is influenced by the principal residual stress ratio and also discuss if such an influence is sufficient in order to determine the size and direction of such stresses in an experimental situation. It should be emphasized that this work does not suggest a new approach to residual stress determination (by indentation testing) but investigates the applicability of previously derived methods to a situation where the surface stress field is not simplified as equi-biaxial or uniaxial. For simplicity, but not out of necessity, only cone indentation of elastic-perfectly plastic materials is considered.

Effects of Torsion on Equivalent Bending Moment for Limit Load and EPFM Circumferential Pipe Flaw Evaluations

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Phuong H. Hoang ◽  
Kunio Hasegawa ◽  
Bostjan Bezensek ◽  
Yinsheng Li
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Large Strain ◽  
Bending Moment ◽  
Limit Load ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Weighted Factor ◽  
Elastic Perfectly Plastic

The circumferential flaw evaluation procedures in ASME Boiler and Pressure Vessel Code Section XI nonmandatory Appendix C are currently limited to straight pipes under pressure and bending loads without consideration of torsion loading. The Working Group on Pipe Flaw Evaluation of the ASME Boiler and Pressure Vessel Code is developing guidance for considering the effects of torsion by a mean of an equivalent bending moment, which is a square root of sum square combination of bending moment and torsion load with a weighted factor for torsion moment. A torsion weighted factor, Ce, is established in this paper using large strain finite element limit load analysis with elastic perfectly plastic materials. Planar flaws and nonplanar flaws in a 10.75 in. (273 mm) OD pipe are investigated. Additionally, a finite element J-integral calculation is performed for a planar through wall circumferential flaw with elastic plastic materials subjected to bending and torsion load combinations. The proposed Ce factor for planar flaws is intended for use with the ASME B&PV Code Section XI, Appendix C for limit load and Elastic Plastic Fracture Mechanics (EPFM) circumferential planar flaw evaluations.

Buckle Propagation Analysis of Deep-Water Petroleum Transmission Pipelines with Axial Tension

2014 ◽  
Vol 1008-1009 ◽  
pp. 1134-1143 ◽  
Author(s):  
Sun Ting Yan ◽  
Yin Fa Zhu ◽  
Zhi Jiang Jin ◽  
Hao Ye
Keyword(s):  
Plastic Hinge ◽  
External Pressure ◽  
Isotropic Hardening ◽  
Rigid Plastic ◽  
Perfectly Plastic ◽  
Fitting Procedure ◽  
Plastic Materials ◽  
Buckle Propagation ◽  
Elastic Perfectly Plastic ◽  
Hinge Model

Quasi-static finite element simulation is carried out on buckle propagation phenomenon of offshore pipelines under external pressure. Arc-length method and volume-controlled static analysis by employing hydrostatic fluid element F3D4 are employed to calculate the steady buckle propagation pressure. After verifying the validity of numerical model, emphasis is on the influence of tension on propagation pressure considering isotropic hardening elastoplastic and elastic-perfectly plastic materials. Parametric study is conducted to include the effect of diameter-thickness ratio, after which two empirical equations are derived by curve fitting procedure. Finally, some comments on the results obtained through rigid-plastic hinge model are presented and a modified plastic hinge model including effect of material anisotropy is derived. The results can serve as a reference for more reasonable design of buckle arrestors.

The Influence of Large Deflections on the Behavior of Rigid-Plastic Cylindrical Shells Loaded Impulsively

1970 ◽  
Vol 37 (2) ◽  
pp. 416-425 ◽  
Author(s):  
Norman Jones
Keyword(s):  
Cylindrical Shells ◽  
Dynamic Loads ◽  
Large Deflections ◽  
Finite Deflections ◽  
Shell Material ◽  
Governing Equations ◽  
Rigid Plastic ◽  
Perfectly Plastic ◽  
Dynamic Analyses ◽  
Circular Cylindrical Shells

A theoretical investigation is herein undertaken in order to examine the response of circular cylindrical shells subjected to dynamic loads of an intensity sufficient to cause large permanent deformations. The shell material is assumed to be rigid, perfectly plastic and the influence of finite deflections is retained in the governing equations. It emerges clearly from the study that geometry changes influence markedly the shell behavior even for quite small deflections and, therefore, they should be retained in any dynamic analyses of cylindrical shells with axial restraints.

Free-Edge Plastic Buckling of Axially Compressed Cylindrical Shells

1968 ◽  
Vol 35 (1) ◽  
pp. 73-79 ◽  
Author(s):  
S. C. Batterman
Keyword(s):  
Boundary Conditions ◽  
Finite Length ◽  
Cylindrical Shells ◽  
Free Edge ◽  
Numerical Results ◽  
Negligible Effect ◽  
Tangent Modulus ◽  
Plastic Buckling ◽  
Simple Support ◽  
Axisymmetric Plastic

Axisymmetric plastic buckling of axially compressed cylindrical shells is studied for semi-infinite shells and shells of finite length subject to free-edge boundary conditions. It is shown that the length of the cylinder has a negligible effect on the buckling load. Reductions in buckling stresses from the classical simple-support value are significant, with the amount of reduction dependent on the details of the variation of tangent modulus with stress. Numerical results are presented for cylinders composed of 2024-T4 aluminum and 3003-0 aluminum.

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