Stability Analysis of Floating-Roof Tanks under Differential Settlement

2010 ◽  
Vol 163-167 ◽  
pp. 55-60
Author(s):  
Yang Zhao ◽  
Xiang Lei ◽  
Xing Zhang
Keyword(s):  
Local Buckling ◽  
Structural Response ◽  
Nonlinear Behavior ◽  
Differential Settlement ◽  
Tank Wall ◽  
Buckling Behavior ◽  
Steel Tanks ◽  
Post Buckling ◽  
Cylindrical Steel Tanks ◽  
Cylindrical Steel

Vertical cylindrical steel tanks are sensitive to differential settlement beneath the tank wall. Most previous studies were based on idealized harmonic settlement, however, for thin shell structures of high nonlinear behavior, it is obviously inappropriate to obtain the results under real settlement by simple summation of harmonic solutions. Real settlement of steel tanks can be grouped into two types - global differential settlement and local differential settlement. This paper examines the nonlinear response and stability behavior of floating-roof steel tanks under both types of settlement. It is shown that, for tanks under global differential settlement, local buckling occurs at the eave ring, followed by a stable post-buckling behavior, and final failure is by overall buckling of the tank shell; while for tanks under local differential settlement, the structural response is related to the degree of localization. At highly localized settlement, local snap-through buckling occurs at the tank wall, but it does not lead to a serious consequence, and the post-buckling behavior can also be utilized in design.

scholarly journals The modal analysis of cylindrical steel tank with selfsupported roof filled with different level of liquid

2013 ◽  
Vol 12 (2) ◽  
pp. 205-212
Author(s):  
Daniel Burkacki ◽  
Michał Wójcik ◽  
Robert Jankowski
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Environmental Disaster ◽  
Natural Modes ◽  
Liquid Products ◽  
Safety And Reliability ◽  
Steel Tank ◽  
Steel Tanks ◽  
Cylindrical Steel Tanks ◽  
Cylindrical Steel

In technical branches, such as chemical or petroleum industries, cylindrical steel tanks are essential structures used for storage of liquid products. Therefore, their safety and reliability is essential, because any failure might have dangerous consequences, in extreme cases may even lead to an environmental disaster. The aim of the presented paper is to show the results of the modal analysis concerning the cylindrical steel tank with self-supported roof which has been constructed in northern Poland. The investigation was carried out with the use of the FEM commercial computer program Abaqus. The values of natural frequencies, as well as the natural modes, for different levels of liquid filling (empty tank, partly filled and tank fully filled) were determined in the study. The results of the study clearly indicate that the increase in the liquid level leads to the substantial decrease in the natural frequencies of the structure.

Post-Buckling of Piezoelectric Thin Plates

2015 ◽  
Vol 15 (07) ◽  
pp. 1540020 ◽  
Author(s):  
Michael Krommer ◽  
Hans Irschik
Keyword(s):  
Nonlinear Partial Differential Equation ◽  
Nonlinear Behavior ◽  
Dirichlet Boundary Conditions ◽  
Thin Plates ◽  
Governing Equations ◽  
Simply Supported ◽  
Buckling Behavior ◽  
Single Term ◽  
Post Buckling ◽  
Special Case

In the present paper, the geometrically nonlinear behavior of piezoelastic thin plates is studied. First, the governing equations for the electromechanically coupled problem are derived based on the von Karman–Tsien kinematic assumption. Here, the Berger approximation is extended to the coupled piezoelastic problem. The general equations are then reduced to a single nonlinear partial differential equation for the special case of simply supported polygonal edges. The nonlinear equations are approximated by using a problem-oriented Ritz Ansatz in combination with a Galerkin procedure. Based on the resulting equations the buckling and post-buckling behavior of a polygonal simply supported plate is studied in a nondimensional form, where the special geometry of the polygonal plate enters via the eigenvalues of a Helmholtz problem with Dirichlet boundary conditions. Single term as well as multi-term solutions are discussed including the effects of piezoelectric actuation and transverse force loadings upon the solution. Novel results concerning the buckling, snap through and snap buckling behavior are presented.

The Initial Post-buckling Behavior of Face-Sheet Delaminations in Sandwich Composites

2003 ◽  
Vol 70 (2) ◽  
pp. 191-199 ◽  
Author(s):  
G. A. Kardomateas ◽  
H. Huang
Keyword(s):  
Interface Crack ◽  
Transverse Shear ◽  
Compressive Strain ◽  
Sandwich Beam ◽  
Local Buckling ◽  
Face Sheet ◽  
Material System ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Composite Face

Should an interface crack between the layers of the composite face-sheet or between the core and the composite face-sheet of a sandwich beam/plate exists, local buckling and possible subsequent growth of this interface crack (delamination) may occur under compression. In this study, the buckling, and initial post-buckling behavior is studied through a perturbation procedure that is based on the nonlinear beam equations with transverse shear included. Closed-form solutions for the load and midpoint delamination deflection versus applied compressive strain during the initial postbuckling phase are derived. Illustrative results are presented for several sandwich construction configurations, in particular with regard to the effect of material system and transverse shear.

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