Sloshing Characteristics of Single Deck Floating Roofs in Aboveground Storage Tanks: Natural Periods and Vibration Modes

2009 ◽  
Author(s):  
Shoichi Yoshida ◽  
Kazuyoshi Sekine ◽  
Katsuki Iwata
Keyword(s):  
Structural Integrity ◽  
Oil Refining ◽  
Vibration Modes ◽  
Storage Tanks ◽  
Severe Damage ◽  
Element Analysis ◽  
Linear Elastic ◽  
Oil Storage ◽  
Hydrodynamic Coupling ◽  
Roof Design

The floating roofs are widely used to prevent evaporation of content in large oil storage tanks. The 2003 Tokachi-Oki earthquake caused severe damage to the floating roofs due to liquid sloshing. The structural integrity of the floating roofs for the sloshing is urgent issue to establish in the petrochemical and oil refining industries. This paper presents the sloshing characteristics of the single deck floating roofs in cylindrical storage tanks. The hydrodynamic coupling of fluid and floating roof is taken into consideration in the axisymmetric finite element analysis. It is assumed that the fluid is incompressible and inviscid, and the floating roof is linear elastic while the sidewall and the bottom are rigid. The basic vibration characteristics, natural periods and vibration modes, of the floating roof due to the sloshing are investigated. These will give engineers important information on the floating roof design.

Eulerian Finite Element Formulation for Sloshing Response of Floating Roofs in Aboveground Storage Tanks

2008 ◽  
Author(s):  
Shoichi Yoshida ◽  
Kazuyoshi Sekine ◽  
Tsukasa Mitsuta
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Integrity ◽  
Dynamic Pressure ◽  
Oil Refining ◽  
Element Formulation ◽  
Storage Tanks ◽  
Element Analysis ◽  
Oil Storage ◽  
Hydrodynamic Coupling

The floating roofs are widely used to prevent evaporation of content in large aboveground oil storage tanks. The 2003 Tokachi-Oki earthquake caused severe damage to the floating roofs due to liquid sloshing. The structural integrity of the floating roofs for the sloshing is urgent issue to establish in petrochemical and oil refining industries. This paper presents the axisymmetric finite element analysis for the sloshing response of floating roofs in cylindrical storage tanks. The hydrodynamic coupling of fluid and floating roof under seismic excitation is taken into consideration in the analysis. It is assumed that the fluid is incompressible and inviscid, and the roof is linear elastic while the sidewall and the bottom are rigid. The theory for the finite element analysis in which the behavior of the fluid is formulated in terms of dynamic pressure as the Eulerian approach is developed. The basic vibration characteristics of the floating roof, such as natural periods and vibration modes, can be obtained from this analysis. These will give engineers important information on the floating roof design.

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.

Simplified Development Method of FEA Code for Sloshing of Floating Roof Tanks (Lagrangian Formulation for Axisymmetric Linear Problem)

2014 ◽  
Author(s):  
Shoichi Yoshida
Keyword(s):  
Linear Problem ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Computational Time ◽  
Storage Tanks ◽  
Coupling Vibration ◽  
Development Method ◽  
Oil Storage ◽  
Fluid Behavior ◽  
Computer Codes

Floating roofs are widely used to prevent evaporation of content in large cylindrical aboveground oil storage tanks. The 2003 Hokkaido Earthquake caused severe damages to the floating roofs due to sloshing. These accidents became a cause to establish structural integrity of the floating roof tanks in sloshing. However, many designers do not have a solution for the sloshing of floating roof tanks except for three-dimensional FEA computer codes. The three-dimensional FEA requires a long computational time and expenses. The sloshing of floating roof tanks is a coupling vibration problem with fluid and structure. The simplified and convenient method has been desired for this solution. This paper presents a simplified development method of a FEA code in the axisymmetric linear problem. It is performed to modify an existing structural analysis code. The fluid behavior is formulated in terms of displacement as the Lagrangian approach.

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.

Behavior of Localized Bottom Bulge in Aboveground Oil Storage Tanks Under Liquid Pressure

2001 ◽  
Vol 124 (1) ◽  
pp. 59-65
Author(s):  
Shoichi Yoshida
Keyword(s):  
Plastic Strain ◽  
Plate Thickness ◽  
Deformation Analysis ◽  
Bottom Plate ◽  
Storage Tanks ◽  
Liquid Pressure ◽  
Element Analysis ◽  
Oil Storage ◽  
Relationship Of ◽  
The Relationship

The bottom plate of aboveground oil storage tanks can bulge, separating from the foundation due to welding deformation. When such a bulge is subjected to liquid pressure, it deforms continuously to make contact with the foundation from the edge, and the remaining area of the bulge decreases with increasing liquid pressure. As a result, the deformation is extremely localized and plastic strain occurs at the bulge. This paper presents a plane strain finite element analysis for the evaluation of localized bottom bulges in aboveground oil storage tanks. Load-incremental, elastic-plastic large deformation analysis is carried out considering the bottom plate contact with the foundation. The relationship of the plastic strain at the bulged bottom plate to the liquid pressure is discussed together with the deformation of the bulge. As a result, the bottom plate thickness has a significant effect on the deformation, but the bulged height does not. After the bulged center makes contact with the foundation, the stress and strain do not increase with increasing liquid pressure. In addition, the permissible bulged profile specified by API Standard 653 elastically deforms to make contact with the foundation under low liquid pressure.

Fitness-for-Service Assessment of Hydrocarbon Storage Tanks

2010 ◽  
Author(s):  
Forhad Ahmad ◽  
M. M. Hossain ◽  
R. Seshadri
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Integrity ◽  
Corrosion Damage ◽  
Storage Tanks ◽  
Element Analysis ◽  
Strength Factor ◽  
Operational Safety ◽  
Industrial Storage ◽  
Hydrocarbon Storage

Storage tanks are widely used in the industry to store hydrocarbon products. Corrosion damage is considered to be a serious threat to the structural integrity of the industrial storage tanks if it occurs on the primary pressure containment boundary. Therefore, fitness-for-service (FFS) assessment of these structures is performed periodically in order to ensure the operational safety and structural integrity. In this paper, evaluation methods are proposed for FFS assessment of storage tanks undergoing corrosion damage. The proposed methods are shown to give reasonably accurate and conservative assessment of the remaining strength factor. The methods are demonstrated through an example and the results verified by inelastic finite element analysis.

Fitness-for-Service Assessment of Hydrocarbon Storage Tanks

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
F. Ahmad ◽  
M. M. Hossain ◽  
R. Seshadri
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Integrity ◽  
Corrosion Damage ◽  
Storage Tanks ◽  
Element Analysis ◽  
Strength Factor ◽  
Operational Safety ◽  
Industrial Storage ◽  
Hydrocarbon Storage

Storage tanks are widely used in the industry to store hydrocarbon products. Corrosion damage is considered to be a serious threat to the structural integrity of the industrial storage tanks if it occurs on the primary pressure containment boundary. Therefore, fitness-for-service (FFS) assessment of these structures is performed periodically in order to ensure the operational safety and structural integrity. In this paper, evaluation methods are proposed for FFS assessment of storage tanks undergoing corrosion damage. The proposed methods are shown to give reasonably accurate and conservative assessment of the remaining strength factor. The methods are demonstrated through an example and the results are verified by inelastic finite element analysis.

Behavior of Localized Bottom Depression in Aboveground Oil Storage Tanks Under Liquid Pressure

2004 ◽  
Author(s):  
Shoichi Yoshida
Keyword(s):  
Finite Element Analysis ◽  
Deformation Analysis ◽  
Bottom Plate ◽  
Storage Tanks ◽  
Liquid Pressure ◽  
Element Analysis ◽  
Large Deformation Analysis ◽  
Oil Storage ◽  
Relationship Of ◽  
The Relationship

When constructing the bottom of aboveground oil storage tanks, the bottom plates are first laid out on the flat foundation, and they then are joined by welding the joints in sequence. As the foundation is difficult to be made completely homogeneous over the bottom area, the settlement of the bottom plates is not uniform under liquid pressure. The depressions of the bottom plates are sometimes found at the first internal inspection which is usually made about 10 years after the oil storage. This paper presents plane strain finite element analysis for the localized bottom depression in aboveground oil storage tanks. Load-incremental, elastic-plastic large deformation analysis is carried out considering contact with the foundation. The relationship of the stress at the depressed bottom plate to the liquid pressure is discussed together with the deformation of the depression.

Structural integrity of a welded attachment junction: Analysis and collapse tests

2000 ◽  
Vol 35 (6) ◽  
pp. 567-580 ◽  
Author(s):  
T G F Gray ◽  
D Mackenzie ◽  
A Heaton ◽  
A Lubis
Keyword(s):  
Structural Integrity ◽  
Limit State ◽  
Strength Properties ◽  
Limit States ◽  
Element Analysis ◽  
Design Assessment ◽  
Linear Elastic ◽  
Codes Of Practice ◽  
Load Carrying ◽  
Failure Conditions

The aim of the research described was to establish a sound structural analysis procedure for load-carrying fillet-welded attachments with particular reference to cases where the welds are well separated by crack-like discontinuities. Finite element analysis (FEA) was used to determine linear elastic fracture mechanics stress intensities and limit states for a range of typical attachment geometries, on the assumption that these two failure conditions represent practical extremes of behaviour. The influence of differences between the yield strengths of the parent materials and the welds was explored in the theoretical study. The results of the FEA were analysed to obtain the development of appropriate design/assessment formulae, based on simple structural mechanics models. These formulae provide an approach that improves on current codes of practice, which treat the loads on welds as statically determinate and ignore crack-related failure potential. Collapse tests were carried out on two-dimensional models of the cases studied. These included specimens where the strength properties were uniform throughout and others where higher-yield-strength welds were incorporated. The results confirmed the FEA results and associated formula with respect to the limit state and provided some insight into the effects of heterogeneous strength properties in the junction.

scholarly journals Wind-resistant optimization design of large storage tanks in island-type petrochemical parks

2021 ◽  
Vol 261 ◽  
pp. 01017
Author(s):  
Haoran Hu ◽  
Jian Guo ◽  
Bingyuan Hong ◽  
Yan Yan ◽  
Xu Yang ◽  
...  
Keyword(s):  
Crude Oil ◽  
Storage Tank ◽  
Optimization Design ◽  
Ring Structure ◽  
Strong Wind ◽  
Storage Tanks ◽  
Static Structure ◽  
Element Analysis ◽  
Oil Storage ◽  
The Finite Element Analysis

Due to the thin-walled wind-sensitive structures of large crude oil storage tanks, it is necessary to consider the wind load failure of oil storage tanks in coastal areas under strong wind conditions during the design process. Based on the finite element analysis software ANSYS\Workbench, the static structure analysis and buckling analysis of the 100, 000 cubic crude oil storage tanks are carried out. In order to solve the buckling failure phenomenon, a wind-resistant ring structure was optimal designed for the crude oil storage tank according to standards, so that the storage tank can withstand hurricanes and typhoons above level 12 with a wind speed of 137 km/h.

Sign in / Sign up

Export Citation Format

Share Document