Nonlinear Finite Element Analysis of Unanchored Steel Liquid Storage Tanks Subjected to Seismic Loadings

2017 ◽  
Author(s):  
Hoang Nam Phan ◽  
Fabrizio Paolacci ◽  
Philippe Mongabure
Keyword(s):  
Finite Element ◽  
Free Surface ◽  
Power Plants ◽  
Nonlinear Dynamic Analysis ◽  
Analysis Procedure ◽  
Nonlinear Finite Element ◽  
Shaking Table ◽  
Storage Tanks ◽  
Liquid Storage ◽  
Seismic Loadings

Steel liquid storage tanks are widely used in industries and nuclear power plants. Damage in tanks may cause a loss of containment, which could result in serious economic and environmental consequences. For the purpose of the earthquake-resistant design of tanks, it is important to use a rational and reliable nonlinear dynamic analysis procedure. The analysis procedure should be capable of evaluating not only the comprehensive seismic responses but also the damage states of tank components under artificial or real earthquakes. The present paper deals with the nonlinear finite element modeling of steel liquid storage tanks subjected to seismic loadings. A reduce-scale unanchored steel liquid storage tank with the broad configuration from a shaking stable test (i.e., the INDUSE-2-safety project) is selected for this study. The fluid-structure interaction problem of the tank-liquid system is analyzed using the Abaqus software with an explicit time integration approach. In particular, the steel tank is modeled based on a Lagrangian formulation, while an Arbitrary Lagrangian-Eulerian adaptive mesh is used in the liquid domain to permit large deformations of the free surface sloshing. The finite element results in terms of the sloshing of the liquid free surface and the uplift response of the base plate are evaluated and compared with the experimental data that is obtained from the shaking table test for the tank under the INDUSE-2-safety project.

Investigation on Buckling Behavior of Cylindrical Liquid Storage Tanks Under Seismic Excitation: 2nd Report — Investigation on the Nonlinear Ovaling Vibration at the Upper Wall

2003 ◽  
Author(s):  
Hideyuki Morita ◽  
Tomohiro Ito ◽  
Koji Hamada ◽  
Akihisa Sugiyama ◽  
Yoji Kawamoto ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Pressure Effects ◽  
Storage Tanks ◽  
Response Level ◽  
Vertical Excitation ◽  
Liquid Storage ◽  
Buckling Behavior ◽  
Thin Walled ◽  
Scaled Models

When a thin walled cylindrical liquid storage tank suffers a large seismic base excitation, buckling phenomena such as elephant foot bulge at the bottom portion and nonlinear ovaling vibration at the upper portion shows nonlinearity between the input and response level and suddenly occurs for the excessive input level, thus will be called as “nonlinear ovaling vibration” hereafter in this paper, may be caused. In the 1st report, the elephant foot bulge phenomena and the liquid pressure effects were investigated. In this 2nd report of the series of studies, the effect of nonlinear ovaling vibration phenomena were investigated based on the dynamic buckling tests using scaled models of thin walled cylindrical liquid storage tanks for nuclear power plants. The mechanism and the effect of vertical excitation and liquid sloshing were also studied and discussed.

Verification Test for Hybrid Seismic Experimental Method Using Nonlinear Finite Element Method

2005 ◽  
Author(s):  
Yoshihiro Dozono ◽  
Mayumi Fukuyama ◽  
Toshihiko Horiuchi ◽  
Takao Konno ◽  
Michiya Sakai ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Experimental Method ◽  
Large Scale ◽  
Branch Pipe ◽  
Nonlinear Finite Element ◽  
Shaking Table ◽  
Piping System ◽  
Analysis Tool ◽  
Seismic Testing

An improved substructure hybrid seismic experimental method has been developed. This method consists of numerical computations using a general-purpose nonlinear finite element analysis tool and a pseudo-dynamic vibration test. Therefore, it enables seismic testing of large-scale structures that cannot be loaded onto a shaking table. The method also visualizes both data measured by sensors placed on the specimen and the results of the numerical analysis, and it helps us to understand the behavior of an entire structure consisting of a specimen and a numerical model. We performed verification tests for a piping system, in which we used a numerical model including supports, valves, and a branch pipe, and a specimen including two elbows. As results of tests, we conclude that the developed system has enough accuracy to be used as a seismic testing method.

Investigation on Buckling Behavior of Cylindrical Liquid Storage Tanks Under Seismic Excitation: 1st Report — Investigation on Elephant Foot Bulge

2003 ◽  
Author(s):  
Tomohiro Ito ◽  
Hideyuki Morita ◽  
Koji Hamada ◽  
Akihisa Sugiyama ◽  
Yoji Kawamoto ◽  
...  
Keyword(s):  
Storage Tank ◽  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Storage Tanks ◽  
Scaled Model ◽  
Liquid Storage ◽  
Shear Buckling ◽  
Thin Walled ◽  
Liquid Storage Tank

When a thin walled cylindrical liquid storage tank suffers a large seismic base excitation, buckling phenomena may be caused such as bending buckling at the bottom portion and shear buckling at the middle portion of the tank. However, the dynamic behaviors of the tanks is not fully clarified, especially those from the occurrence of buckling to some failures. In this study, bending buckling phenomena were focused which will be categorized as diamond buckling and elephant foot bulge. As ones of a series of studies, dynamic buckling tests were performed using large scale liquid storage tank models simulating thin walled cylindrical liquid storage tanks in nuclear power plants. The input seismic acceleration was increased until the elephant foot bulge occurred, and the vibrational behavior before and after buckling was investigated. In addition to the large scaled model tests, fundamental tests using small scaled tank models were also performed in order to clarify the effects of dynamic liquid pressure on the buckling threshold and deformation patterns.

scholarly journals Generalized SDOF system for dynamic analysis of concrete rectangular liquid storage tanks

2021 ◽  
Author(s):  
Jun Zheng Chen
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Seismic Analysis ◽  
Design Procedure ◽  
Hydrodynamic Pressure ◽  
Added Mass ◽  
Tank Wall ◽  
Storage Tanks ◽  
Sdof System ◽  
Liquid Storage

Liquid storage tanks are essential facilities in lifeline and industrial systems. To ensure liquid tightness, serviceability is the prime design concern for these structures. While there have been major studies on the behavior of steel tanks, little attention has been paid to the behavior of rectangular concrete tanks. In this study, the dynamic response of concrete rectangular liquid storage tanks is investigated. In the current design practice, the response of liquid and tank structure is determined based on rigid tank wall and the lumped mass approach. However, the results of analysis show that the flexibility of tank wall increases the hydrodynamic pressures as compared to the rigid wall assumption. Also, recent studies show that the lumped added mass method leads to overly conservative results in terms of base shear and base moment. In addition, in spite of advanced analysis techniques available for dynamic analysis of liquid storage tanks such as finite element method and sequential coupling analysis procedure, there is a need to develop a simplified analysis method for practical applications. In this thesis, a simplified method using the generalized single degree of freedom (SDOF) system is proposed for seismic analysis of concrete rectangular liquid containing structures (LCS). Only the impulsive hydrodynamic pressure is considered. In the proposed method, the consistent mass approach and the effect of flexibility of tank wall on hydrodynamic pressures are considered. Different analytical methods are used to verify the proposed model in this study. The comparison of results based on the current design practice, the analytical-finite element models and full finite element model using ANSYS® shows that the proposed method is fairly accurate which can be used in the structural design of liquid containing structures. Parametric studies on seismic analysis of concrete rectangular LCS using the generalized SDOF system are carried out. Five prescribed vibration shape functions representing the first mode shape of fluid structure interaction system are used to study the effect of flexibility of tank wall and boundary conditions. The effect of flexibility of tank wall, the amplitude of hydrodynamic pressure, the added mass of liquid due to hydrodynamic pressure, the effective heights for liquid containing system and the effect of higher modes on dynamic response of LCS are investigated. In addition, the effect of variable size of tanks and liquid depth are studied. The contribution of higher modes to the dynamic response of LCS is included in the proposed model. A design procedure based on the structural model using the generalized SDOF system is proposed in this study. Design charts and tables for the added mass of liquid due to impulsive hydrodynamic pressure and the corresponding effective heights are presented. The proposed design procedure can be used for engineering design applications.

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