Elastic buckling of cylindrical pipe linings with small imperfections subject to external pressure

1997 ◽  
Vol 12 ◽  
pp. 3-15 ◽  
Author(s):  
J.C. Boot
Keyword(s):  
External Pressure ◽  
Elastic Buckling ◽  
Cylindrical Pipe

Elastic buckling of thin-walled polyhedral pipe liners encased in a circular pipe under uniform external pressure

2018 ◽  
Vol 123 ◽  
pp. 214-221 ◽  
Author(s):  
Zhaochao Li ◽  
Yan Tang ◽  
Fujian Tang ◽  
Yizheng Chen ◽  
Genda Chen
Keyword(s):  
External Pressure ◽  
Circular Pipe ◽  
Elastic Buckling ◽  
Uniform External Pressure ◽  
Thin Walled

Buckling of Fibre-Reinforced Plastic-Steel Torispherical Shells Under External Pressure

1988 ◽  
Vol 202 (6) ◽  
pp. 409-420 ◽  
Author(s):  
G D Galletly ◽  
A Muc
Keyword(s):  
External Pressure ◽  
Experimental Results ◽  
Steel Shell ◽  
Elastic Buckling ◽  
Geometrical Parameters ◽  
Initial Shape ◽  
Buckling Modes ◽  
Reinforced Plastic ◽  
Composite Layers ◽  
Spherical Caps

The paper deals with the buckling of torispherical shells consisting of a steel external layer plus different numbers of composite layers. It is assumed that the total thickness of the fibre-reinforced plastic (FRP)-steel shell is constant but that the thickness of the steel and of the composite may be varied. In the paper it is shown (a) how the orientation of the fibres and the composite lamina thicknesses affect the elastic buckling modes and (b) how substantial increases in elastic buckling pressures may be achieved by reinforcing the steel torispheres with layers of composite. The analysis is carried out for various values of the geometrical parameters describing torispheres, including spherical caps. The influence of the yielding of the steel layer on the buckling pressures of FRP-steel torispheres is also discussed. As might be expected, it is necessary to take plasticity into account when predicting the buckling pressures of these shells. Some experimental results are given which confirm this expectation. The effect of initial shape imperfections in the shells is also considered briefly. However, the dearth of experimental results on FRP-steel shells prevents a proper evaluation of the way in which imperfections decrease their buckling strength.

Dent Imperfections in Shell Buckling: The Role of Geometry, Residual Stress, and Plasticity

2020 ◽  
Vol 88 (3) ◽  
Author(s):  
S. Gerasimidis ◽  
J. W. Hutchinson
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Middle Surface ◽  
External Pressure ◽  
Second Step ◽  
Elastic Buckling ◽  
Spherical Shells ◽  
Shell Buckling ◽  
Cylindrical Metal

Abstract Departures of the geometry of the middle surface of a thin shell from the perfect shape have long been regarded as the most deleterious imperfections responsible for reducing a shell’s buckling capacity. Here, systematic simulations are conducted for both spherical and cylindrical metal shells whereby, in the first step, dimple-shaped dents are created by indenting a perfect shell into the plastic range. Then, in the second step, buckling of the dented shell is analyzed, under external pressure for the spherical shells and in axial compression for the cylindrical shells. Three distinct buckling analyses are carried out: (1) elastic buckling accounting only for the geometry of the dent, (2) elastic buckling accounting for both dent geometry and residual stresses, and (3) a full elastic–plastic buckling analysis accounting for both the dent geometry and residual stresses. The analyses reveal the relative importance of the geometry and the residual stress associated with the dent, and they also provide a clear indicator of whether plasticity is important in establishing the buckling load of the dented shells.

Elastic Buckling of Thin-Walled Liners Encased in Partially Grouted Pipelines under External Pressure

2020 ◽  
Vol 146 (4) ◽  
pp. 04020042 ◽  
Author(s):  
Zhaochao Li ◽  
Fujian Tang ◽  
Yizheng Chen ◽  
Yan Tang ◽  
Genda Chen
Keyword(s):  
External Pressure ◽  
Elastic Buckling ◽  
Thin Walled

Plastic General Instability of Ring—Reinforced Conical Shells Under Uniform External Pressure

2007 ◽  
Vol 44 (04) ◽  
pp. 268-277
Author(s):  
Carl T.F. Ross ◽  
Andrew P. F. Little ◽  
Robert Allsop ◽  
Charles Smith ◽  
Marcus Engelhardt
Keyword(s):  
Experimental Tests ◽  
External Pressure ◽  
Elastic Buckling ◽  
Conical Shells ◽  
Uniform External Pressure ◽  
Design Chart ◽  
Circular Conical Shells ◽  
High Degree ◽  
Very High ◽  
Ring Shell

The paper describes experimental tests carried out on three ring-reinforced circular conical shells that suffered plastic general instability under uniform external pressure. In this mode, the entire ring-shell combination buckles bodily in its flank. The cones were carefully machined from EN1A mild steel to a very high degree of precision. The paper also provides a design chart using the results obtained from these three vessels, together with the results of nine other vessels obtained from other tests. All 12 vessels failed by general instability. The design chart allows the possibility of obtaining a plastic knockdown factor, so that the theoretical elastic buckling pressures for perfect vessels can be divided by the plastic knockdown factor, to give the predicted buckling pressure. This method can also be used for the design of full-scale vessels.

ELASTIC BUCKLING OF EXTERNALLY-PRESSURIZED IMPERFECT TOROIDAL SHELLS

2001 ◽  
Vol 01 (01) ◽  
pp. 31-45 ◽  
Author(s):  
GERARD D. GALLETLY
Keyword(s):  
Initial Imperfection ◽  
External Pressure ◽  
Elastic Buckling ◽  
Geometric Imperfections ◽  
Buckling Modes ◽  
Initial Imperfections ◽  
Numerical Studies ◽  
Initial Geometric Imperfections ◽  
Sinusoidal Buckling ◽  
Toroidal Shells

This paper summarizes the results of numerical studies into the effects of initial geometric imperfections on the elastic buckling behaviour of steel circular and elliptic toroidal shells subjected to follower-type external pressure. The types of initial imperfection studied are (a) axisymmetric localized ones and (b) sinusoidal buckling modes. The principal localized imperfections studied are (i) circular increased-radius "flat spots" and (ii) smooth dimples. The buckling pressures pcr of circular toroidal shells were not very sensitive to initial imperfections. With elliptic toroids, whether the shell was sensitive to initial imperfections or not depended on the ratio k(≡ a/b) of major to minor radii of the section. The shells on the ascending part of the pcr versus k curve behaved like circular toroidal shells, i.e. they were not sensitive to initial imperfections. However, the behaviour of elliptic toroids on the descending part of the versus k curve was very different. The numerical results quoted in the paper are for limited ranges of the geometric parameters. It would be useful to extend these ranges, to explore the effects of plasticity and to conduct model tests on imperfect steel models to verify the conclusions of the numerical studies.

Buckling Behavior of Clamped Laminated Composite Cylindrical Shells under External Pressure Using Finite Element Method

2011 ◽  
Vol 121-126 ◽  
pp. 43-47
Author(s):  
Behzad Abdi ◽  
Hamid Mozafari ◽  
Ayob Amran ◽  
Roya Kohandel
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cylindrical Shells ◽  
Laminated Composite ◽  
External Pressure ◽  
Elastic Buckling ◽  
Fiber Angle ◽  
Buckling Behavior ◽  
Critical Buckling Pressure ◽  
Composite Cylindrical Shells

In this study, the elastic buckling behavior of clamped laminated composite cylindrical shells under external pressure was studied. The Finite Element Method (FEM) was used to predict the critical elastic buckling pressure behavior when composite cylindrical shells were subjected to external pressure. The edges of the cylindrical shell ends were completely constrained to simulate clamped end conditions. The influences of parameters such as wall thickness, fiber angle, number of layers and L/R ratio of laminated composite cylindrical shells on critical buckling pressure were studied. It has been found that the under external pressure, the thickness and the fiber angle of the layers have the most significant effect on the critical buckling pressure.

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