Lower Bound Buckling Load of a Floating Roof Pontoon

2010 ◽  
Author(s):  
Shoichi Yoshida
Keyword(s):  
Finite Element ◽  
Lower Bound ◽  
Large Diameter ◽  
Buckling Load ◽  
Bottom Plate ◽  
Element Analysis ◽  
Oil Storage ◽  
Bending Load ◽  
Stiffness Method ◽  
Shell Finite Element

The 2003 Tokachi-Oki earthquake caused severe damage to oil storage tanks due to liquid sloshing. Seven single-deck floating roofs had experienced sinking failures in large diameter tanks at a refinery in Tomakomai, Japan. The pontoons of the floating roofs might be buckled due to bending load during the sloshing. The content in the tank was spilled on the floating roof from small failures which were caused in the welding joints of pontoon bottom plate by the buckling. Then the floating roof began to lose buoyancy and sank into the content slowly. The elastic buckling of the pontoon is important from the viewpoint of the single-deck floating roof sinking. The authors had reported the buckling strength of the pontoons subjected to bending and compressive loads in the published literatures. The axisymmetric shell finite element method for linear elastic bifurcation buckling was used in the analysis. The buckling characteristics of the pontoon both with and without ring stiffeners were investigated. The initial geometrical imperfection may diminish the buckling load. This paper presents the lower bound buckling load according to the reduced stiffness method proposed by Croll and Yamada. The lower bound buckling loads of the pontoon subjected to circumferential bending load are evaluated from the axisymmetric finite element analysis which includes the reduced stiffness method.

Buckling of Single-Deck Floating Roofs in Aboveground Oil Storage Tanks Due to Circumferential Bending Load

2006 ◽  
Author(s):  
Shoichi Yoshida ◽  
Kazuhiro Kitamura
Keyword(s):  
Large Diameter ◽  
Bending Moment ◽  
Bottom Plate ◽  
Storage Tanks ◽  
Element Analysis ◽  
Buckling Strength ◽  
Structural Problems ◽  
Oil Storage ◽  
Bending Load ◽  
Shell Finite Element

The 2003 Tokachi-Oki earthquake caused severe damage to oil storage tanks due to liquid sloshing. Six single-deck floating roofs had experienced structural problems as evidenced by sinking failure in large diameter tanks at the refinery at Tomakomai, Japan. The pontoon of floating roof might be buckled due to circumferential bending moment during the sloshing. The content in the tank was spilled on the floating roof from small failures which were caused in the rap welding joints of pontoon bottom plate by the buckling. Then the floating roof began to lose buoyancy and submerged into the content slowly. The failure of the roof expanded gradually in the sinking process. It is presumed that the initial small failures were caused by the elastic buckling of the pontoon due to circumferential bending moment. This paper presents the buckling strength of the pontoon using axisymmetric shell finite element analysis. Linear elastic bifurcation buckling analysis is carried out and the buckling characteristics of the pontoon are investigated. The result shows that the thickness of both pontoon roof and bottom plates have significantly affect the buckling strength.

Buckling Characteristics of Floating Roof Pontoons in Aboveground Storage Tanks Subjected to Bending Load in Two Directions

2008 ◽  
Author(s):  
Shoichi Yoshida ◽  
Kazuhiro Kitamura
Keyword(s):  
Large Diameter ◽  
Bending Moment ◽  
Bottom Plate ◽  
Storage Tanks ◽  
Buckling Strength ◽  
Linear Elastic ◽  
Structural Problems ◽  
Oil Storage ◽  
Bending Load ◽  
Shell Finite Element

The 2003 Tokachi-Oki earthquake caused severe damage to aboveground oil storage tanks due to liquid sloshing. Seven single-deck floating roofs had experienced structural problems as evidenced by sinking failure in large diameter tanks at the refinery in Tomakomai, Japan. The pontoons of the floating roofs might be buckled due to circumferential bending moment during the sloshing. The content in the tank was spilled on the floating roof from small failures which were caused at the welding joints of pontoon bottom plate by the buckling. Then the floating roof began to lose buoyancy and submerged into the content slowly. The authors had reported the buckling strength of the pontoons with and without ring stiffeners subjected to circumferential bending load in the previous papers. This paper presents the buckling strength of the pontoons subjected to both circumferential and radial bending load. The axisymmetric shell finite element method is used in the analysis. Linear elastic bifurcation buckling analysis is carried out and the buckling characteristics of the pontoon with and without ring stiffeners are investigated.

Buckling of Ring Stiffened Pontoons of Floating Roofs in Aboveground Oil Storage Tanks

2007 ◽  
Author(s):  
Shoichi Yoshida ◽  
Kazuhiro Kitamura
Keyword(s):  
Large Diameter ◽  
Bending Moment ◽  
Bottom Plate ◽  
Storage Tanks ◽  
Element Analysis ◽  
Linear Elastic ◽  
Structural Problems ◽  
Oil Storage ◽  
Bifurcation Buckling ◽  
Shell Finite Element

The 2003 Tokachi-Oki earthquake caused severe damage to oil storage tanks due to liquid sloshing. Six single-deck floating roofs had experienced structural problems as evidenced by sinking failure in large diameter tanks at the refinery in Tomakomai, Japan. The pontoon of floating roof might be buckled due to circumferential bending moment during the sloshing. The content in the tank was spilled on the floating roof from small failures which might be caused in the lap-welded joints or in the stress concentrated parts of the pontoon bottom plate by the buckling. Then the floating roof began to lose buoyancy and submerged into the content slowly. The failure of the roof expanded gradually in the sinking process. It is presumed that the initial small failures were caused by the elastic buckling of the pontoon due to circumferential bending moment. In this paper, the buckling strength of the pontoon is presented using axisymmetric shell finite element analysis. Linear elastic bifurcation buckling analyses are carried out and the buckling characteristics of ring stiffened pontoons are investigated.

Buckling Characteristics of Floating Roof Pontoons in Aboveground Storage Tanks Subjected to Both Compressive and Bending Load

2009 ◽  
Author(s):  
Shoichi Yoshida
Keyword(s):  
Large Diameter ◽  
Compressive Load ◽  
Bending Moment ◽  
Bottom Plate ◽  
Storage Tanks ◽  
Buckling Strength ◽  
Structural Problems ◽  
Oil Storage ◽  
Bending Load ◽  
Shell Finite Element

The 2003 Tokachi-Oki earthquake caused severe damage to oil storage tanks due to liquid sloshing. Seven single-deck floating roofs had experienced structural problems as evidenced by sinking failure in large diameter tanks at a refinery in Tomakomai, Japan. The pontoons of the floating roofs might be buckled due to circumferential bending moment during the sloshing. The content in the tank was spilled on the floating roof from small failures which were caused in the welding joints of pontoon bottom plate by the buckling. Then the floating roof began to lose buoyancy and sank into the content slowly. The authors had reported the buckling strength of the pontoons subjected to circumferential bending load first and that of the pontoons subjected to both circumferential and radial bending load next in the previous papers. This paper presents the buckling strength of the pontoons subjected to both circumferential bending load and circumferential compressive load. The axisymmetric shell finite element method is used in the analysis. Linear elastic bifurcation buckling analysis is carried out and the buckling characteristics of the pontoon both with and without ring stiffeners are investigated.

Seismic Response Analysis for Sloshing of a Single-Deck Floating Roof With Center Pontoon in Oil Storage Tank

2010 ◽  
Author(s):  
Shoichi Yoshida ◽  
Kazuyoshi Sekine ◽  
Tomohiko Tsuchida ◽  
Katsuki Iwata
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Seismic Response ◽  
Dynamic Pressure ◽  
Large Diameter ◽  
Response Analysis ◽  
Seismic Response Analysis ◽  
Element Analysis ◽  
Oil Storage ◽  
Hydrodynamic Coupling

Floating roofs are widely used to prevent evaporation of contents of large cylindrical oil storage tanks. The 2003 Tokachi-Oki earthquake caused severe damage to floating roofs due to liquid sloshing. Seven single-deck floating roofs deformed to leak oil on them, and they lost buoyancy to sink. Two of them were the single-deck type with center pontoon in large diameter tanks. The present paper deals with an axisymmetric finite element analysis for the sloshing response of a floating roof with center pontoon. The hydrodynamic coupling of the fluid and the floating roof under seismic excitation is taken into consideration in the analysis. The fluid is assumed to be incompressible and inviscid, and the roof is assumed to be linear elastic. In addition, the sidewall and the bottom are assumed to be rigid. In the finite element analysis, the behavior of the fluid is formulated in terms of dynamic pressure using the Eulerian approach. The basic vibration characteristics of the single-deck floating roof with center pontoon, such as the natural periods and vibration modes, can be obtained from this analysis. These characteristics are shown comparing with those of the single-deck floating roof without center pontoon. The seismic response analysis for the input of an earthquake wave is also performed.

Development and Application of Large Three-Way Hot Tapping Fittings

2004 ◽  
Author(s):  
William Alfons Jarvis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Large Diameter ◽  
Branch Ratio ◽  
Design Codes ◽  
Element Analysis ◽  
Piping Systems ◽  
Current Design ◽  
Shell Finite Element

Background on the development and application of high pressure “large branch ratio” three way tee style hot tapping and plugging fittings on large diameter (16”–54”) pipelines and pressure piping systems in Canada. Examines the limitations and problems in current design codes, for large ratio branch connections, and the good engineering practiced applied based on simple shell finite element analysis.

Buckling characteristics of cut-out borne composite stiffened hyperbolic paraboloid shell panel

2021 ◽  
pp. 146442072110058
Author(s):  
Sarmila Sahoo
Keyword(s):  
Finite Element ◽  
Orientation Angle ◽  
Buckling Load ◽  
Benchmark Problems ◽  
Hyperbolic Paraboloid ◽  
Element Analysis ◽  
Load Effect ◽  
Global Buckling ◽  
Fiber Orientation Angle ◽  
Shell Panel

The present study investigates buckling characteristics of cut-out borne stiffened hyperbolic paraboloid shell panel made of laminated composites using finite element analysis to evaluate the governing differential equations of global buckling of the structure. The finite element code is validated by solving benchmark problems from literature. Different parametric variations are studied to find the optimum panel buckling load. Laminations, boundary conditions, depth of stiffener and arrangement of stiffeners are found to influence the panel buckling load. Effect of different parameters like cut-out size, shell width to thickness ratio, degree of orthotropy and fiber orientation angle of the composite layers on buckling load are also studied. Parametric and comparative studies are conducted to analyze the buckling strength of composite hyperbolic paraboloid shell panel with cut-out.

Some new results and current challenges in the finite element analysis of shells

Acta Numerica ◽  
2001 ◽  
Vol 10 ◽  
pp. 215-250 ◽  
Author(s):  
Dominique Chapelle
Keyword(s):  
Finite Element ◽  
Shell Theory ◽  
Shell Structures ◽  
Engineering Practice ◽  
Element Analysis ◽  
Shell Elements ◽  
Shell Models ◽  
The Finite Element Analysis ◽  
Shell Finite Element ◽  
Mathematical Analyses

This article, a companion to the article by Philippe G. Ciarlet on the mathematical modelling of shells also in this issue of Acta Numerica, focuses on numerical issues raised by the analysis of shells.Finite element procedures are widely used in engineering practice to analyse the behaviour of shell structures. However, the concept of ‘shell finite element’ is still somewhat fuzzy, as it may correspond to very different ideas and techniques in various actual implementations. In particular, a significant distinction can be made between shell elements that are obtained via the discretization of shell models, and shell elements – such as the general shell elements – derived from 3D formulations using some kinematic assumptions, without the use of any shell theory. Our first objective in this paper is to give a unified perspective of these two families of shell elements. This is expected to be very useful as it paves the way for further thorough mathematical analyses of shell elements. A particularly important motivation for this is the understanding and treatment of the deficiencies associated with the analysis of thin shells (among which is the locking phenomenon). We then survey these deficiencies, in the framework of the asymptotic behaviour of shell models. We conclude the article by giving some detailed guidelines to numerically assess the performance of shell finite elements when faced with these pathological phenomena, which is essential for the design of improved procedures.

3-D Elasto-Plastic Contact Finite Element Analysis for Bearings Design

1990 ◽  
Author(s):  
Wang Shigang ◽  
Yu Jun ◽  
Zhou Ji ◽  
Li Mingzhang
Keyword(s):  
Finite Element ◽  
Contact Problem ◽  
Geometrical Nonlinearity ◽  
Contact Problems ◽  
Plastic State ◽  
Element Analysis ◽  
Surface Pressure Distribution ◽  
Tangential Stiffness ◽  
Stiffness Method ◽  
Error Method

Abstract In this paper, A 3-D elasto-plastic contact problem in bearings is studied by Finite Element Method (FEM). A computer program has been developed for this purpose. A trial-error method is employed to cope with the geometrical nonlinearity and a tangential stiffness method is employed to tackle the material nonlinearity appeared in elasto-plastic contact problems. A frictionless contact problem of roller bearings is analysed, the result reveals that in 3-D elasto-plastic state the trend of the contact surface pressure distribution is similar to Hertz problem’s but flater.

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