A Hybrid Control Method to Reduce the Seismic Response of a Liquid Storage Tank

2016 ◽  
Author(s):  
Hao Luo ◽  
Ruifu Zhang ◽  
Dagen Weng
Keyword(s):  
Seismic Response ◽  
Wave Height ◽  
Storage Tank ◽  
Control Method ◽  
Hybrid Control ◽  
Inertial Mass ◽  
Base Shear ◽  
Liquid Storage ◽  
Liquid Storage Tank ◽  
Base Displacement

In this study, a hybrid control method is proposed, in which both isolation bearings and an inertial mass damper (IMD) are used, to reduce the seismic response of a liquid storage tank. First, simplified models of the tank and IMD are illustrated. Next, to evaluate the effectiveness of the proposed method, three tanks, including a fixed tank, an isolated tank and an isolated tank with an IMD, are analyzed and compared. Last, parametric studies are conducted to investigate the effects of equivalent inertial mass and viscous damping of the IMD. It is observed that, compared with the fixed tank, the base shear of the isolated one is largely reduced, whereas the wave height is consequently amplified; for the isolated tank with an IMD, not only is the base shear more obviously reduced, but also the wave height is effectively controlled. What’s more, the base displacement of the isolated tank with an IMD is much lower than that of the isolated one. Therefore, the proposed method can be considered as an effective method to control the seismic response of the liquid storage tanks.

Seismic Response Analysis of Large Liquid Storage Tanks

2012 ◽  
Vol 166-169 ◽  
pp. 2490-2493
Author(s):  
Yuan Zhang ◽  
You Hai Guan
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Storage Tank ◽  
Response Analysis ◽  
Storage Tanks ◽  
Performance Study ◽  
Seismic Response Analysis ◽  
Seismic Safety ◽  
Liquid Storage ◽  
Liquid Storage Tank

Due to frequent earthquakes in recent years, the seismic safety of large storage tank is very important. In this paper, seismic response of large liquid storage tanks is analyzed. A model for liquid storage tank is established firstly. By modality analysis, dynamic behavior of large storage tank is obtained. After the model is excitated by seismic, seismic responses are obtained. The conclusions show that, without considering liquid-solid coupling, "elephant foot" buckling phenomenon doesn’t appear. This study provides reference for seismic design and seismic performance study of large storage tank.

scholarly journals Seismic Analysis of Steel Cylindrical Liquid Storage Tank Using Coupled Acoustic-Structural Finite Element Method For Fluid-Structure Interaction

2020 ◽  
Vol 25 (1) ◽  
pp. 27-40
Author(s):  
Aruna Rawat ◽  
Vasant Matsagar ◽  
A. K. Nagpal
Keyword(s):  
Finite Element ◽  
Storage Tank ◽  
Seismic Analysis ◽  
Ground Motions ◽  
Fe Model ◽  
Base Shear ◽  
Lumped Mass ◽  
Structure Interaction ◽  
Liquid Storage ◽  
Liquid Storage Tank

A seismic analysis of ground-supported, three-dimensional (3-D) rigid-base steel cylindrical liquid storage tank is investigated, using a coupled acoustic-structural finite element (FE) method for fluid-structure interaction (FSI). In this method, the contained liquid in the tank is modelled using acoustic elements and the cylindrical tank is modelled using shell elements. The impulsive and convective terms are estimated separately by using the appropriate boundary conditions on the free surface of the liquid. The convergence and validation studies of the proposed FE model are conducted by comparing the results reported in the literature. The parametric studies are performed for rigid and flexible tanks for the varying slenderness of the open roof tanks. The sloshing displacement and base shear time history responses are evaluated for the 3-D tanks subjected to harmonic unidirectional ground motions. Further, the results are compared with the commonly used two and three lumped-mass models of the tank. Moreover, the seismic response quantities of the tank subjected simultaneously to the bi-directional horizontal components of earthquake ground motion are also investigated using the 3-D FE model, and the response quantities are compared with the lumped-mass models. The results obtained from the 3-D FE model and lumped-mass model are in close agreement. The average percentage difference in the 3-D FE and lumped-mass models for maximum sloshing displacement prediction is 15 percent to 20 percent and that for the base shear is about 4 to 10 percent, in the case of the uni-directional harmonic ground motions. It is concluded that the sloshing displacement is not affected by the tank flexibility, but the impulsive hydrodynamic pressure and the impulsive component of the base shear increases with the tank flexibility.

Study on a Combined Isolation Method for Large LNG Storage Tanks in Soft Site

2013 ◽  
Author(s):  
Dagen Weng ◽  
Shuai Liu
Keyword(s):  
Seismic Response ◽  
Storage Tank ◽  
Design Method ◽  
Horizontal Displacement ◽  
Control Technique ◽  
Seismic Action ◽  
Isolation Layer ◽  
Liquid Storage ◽  
Liquid Storage Tank ◽  
Strong Ground

The fundamental natural frequency that can determine the seismic response of large LNG storage tank is usually within 2Hz∼10Hz, it is in the range of predominant frequency of strong ground motion. It has been proved that the isolation control technique can be adopted to mitigate the seismic action on the liquid storage tank in the hard site, but in the soft site, if the conventional isolation design methods are still be used for seismic mitigation of the large LNG storage tank, the problems that the isolation period is too long, and the horizontal displacement of the isolation layer is too large under strong earthquake will be produced. For these problems, a combined isolation design method that is suitable for soft site is proposed in this paper. Based on the Malhotra’s simplified elastic-wall model of liquid storage tank, the simplified multi-mass mechanical model of combined isolated large LNG storage tank is established, and the seismic response of the LNG storage tank under the case of SSE (safety shutdown earthquake) is analyzed. The results show that the seismic-reduced effectiveness of the combined isolated LNG storage tank is obvious, and the horizontal displacement of isolation layer can be controlled in an acceptable range.

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