Dynamic Buckling Simulation of Cylindrical Liquid Storage Tanks Subjected to Seismic Motions

2010 ◽  
Author(s):  
Akira Maekawa ◽  
Katsuhisa Fujita
Keyword(s):  
Numerical Simulation ◽  
Seismic Response ◽  
Large Deformation ◽  
Three Dimensional ◽  
Mesh Size ◽  
Buckling Analysis ◽  
Dynamic Buckling ◽  
Storage Tanks ◽  
Analysis Method ◽  
Liquid Storage

A three-dimensional and elastic-plastic dynamic buckling analysis method that takes into consideration fluid-structure coupling and large deformation is proposed in order to accurately simulate the seismic response of cylindrical liquid storage tanks. The results of a dynamic buckling experiment of a tank using seismic motions closely match those of numerical simulation by the proposed method. The mesh size of the analytical model greatly influences the buckling analysis results. Optimization of the size is also discussed.

Dynamic Buckling Analysis of Cylindrical Water Storage Tanks: A New Simulation Method Considering Coupled Vibration Between Fluid and Structure

2009 ◽  
Author(s):  
Akira Maekawa ◽  
Katsuhisa Fujita
Keyword(s):  
Shell Structure ◽  
Water Storage ◽  
Safety Margin ◽  
Time History ◽  
Buckling Analysis ◽  
Dynamic Buckling ◽  
Coupled Analysis ◽  
Storage Tanks ◽  
Analysis Method ◽  
Coupled Vibrations

This paper proposes a dynamic buckling analysis method which can accurately simulate the buckling behavior of cylindrical water storage tanks during an earthquake. The proposed method takes into account the behavior of oval-type vibration as well as beam-type vibration, which are coupled vibrations between the shell structure of the tank and the water stored in the tank. In the proposed method, both the tank and the stored water are three-dimensionally modeled by finite elements and time history analysis is conducted. Moreover, coupled analysis between the fluid and structure and large deformation analysis to the shell structure of the tank are also considered. The analytical results by the proposed method agreed well with those of experiments regarding occurrence of oval-type vibration, mode of buckling and buckling load. The method can accurately simulate the seismic response including the coupled vibrations and the process of damage such as buckling of the cylindrical water storage tank during an earthquake. In conclusion, the proposed dynamic buckling analysis method can quantitatively evaluate the seismic performance of water storage tanks such as seismic safety margin.

scholarly journals Response of Base-Isolated Liquid Storage Tanks

2004 ◽  
Vol 11 (1) ◽  
pp. 33-45 ◽  
Author(s):  
M.B. Jadhav ◽  
R.S. Jangid
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Equations Of Motion ◽  
Approximate Model ◽  
Storage Tanks ◽  
Step Method ◽  
Earthquake Excitation ◽  
System Parameters ◽  
Liquid Storage ◽  
Isolation Systems

Seismic response of liquid storage tanks isolated by elastomeric bearings and sliding system is investigated under real earthquake ground motions. The continuous liquid mass of the tank is modeled as lumped masses known as sloshing mass, impulsive mass and rigid mass. The coupled differential equations of motion of the system are derived and solved in the incremental form using Newmark's step-by-step method with iterations. The seismic response of isolated tank is studied to investigate the comparative effectiveness of various isolation systems. A parametric study is also carried out to study the effect of important system parameters on the effectiveness of seismic isolation for liquid storage tanks. The various important parameters considered are: (i) aspect ratio of the tank and (ii) the time period of the isolation systems. It was observed that both elastomeric and sliding systems are found to be effective in reducing the earthquake forces of the liquid storage tanks. However, the elastomeric bearing with lead core is found to perform better in comparison to other systems. Further, an approximate model is proposed for evaluation of seismic response of base-isolated liquid storage tanks. A comparison of the seismic response evaluated by the proposed approximate method and an exact approach is made under different isolation systems and system parameters. It was observed that the proposed approximate analysis provides satisfactory response estimates of the base-isolated liquid storage tanks under earthquake excitation.

The Research of Gantry Crane Girder Damage Problem by Modal Analysis Method

2014 ◽  
Vol 578-579 ◽  
pp. 872-876
Author(s):  
Xiao Peng Nie ◽  
Xin Gang Li ◽  
Hong Wei Fan ◽  
Ke Qin Ding ◽  
Li Bin Xu
Keyword(s):  
Numerical Simulation ◽  
Wavelet Analysis ◽  
Static Analysis ◽  
Damage Identification ◽  
Three Dimensional ◽  
Gantry Crane ◽  
Analysis Method ◽  
Ansys Software ◽  
Vibration Equation ◽  
Damage Location

most crane damage identification of the work has focused on the static analysis, that can't explain whether the crane has a damage or not by this way. So the paper explained the modal signal to analysis this problem , Used 300 tons gantry crane’s beam for background and ANSYS software as a tool was used for numerical simulation. The purpose is to find difference between the damage beam of the crane and health one,because if there was a damage on the beam , the formations and frequency will be changed. This theory of analysis is based on the vibration equation. In order to illustrate it better, the wavelet analysis method as a tool has been used ,in this case the signal was filtered, we can judge the damage location from the three dimensional curve. The basic aim of this paper is to arrive at a better way to judge the damage.Through the above analysis, the results proved the author's idea, identify structural’s damage basically, but it still need further research.

Effects of Base Uplifting on the Seismic Response of Unanchored Liquid Storage Tanks

2012 ◽  
Author(s):  
Maria Vathi ◽  
Spyros A. Karamanos
Keyword(s):  
Seismic Response ◽  
Pushover Analysis ◽  
Hydrodynamic Pressure ◽  
Base Plate ◽  
Seismic Loading ◽  
Storage Tanks ◽  
Liquid Storage ◽  
Detailed Simulation ◽  
Steel Tank ◽  
Static Pushover Analysis

Unanchored liquid storage tanks under strong earthquake loading tend to uplift. In the present study, the effects of base uplifting on the seismic response of unanchored tanks are presented with emphasis on elephant’s foot buckling, base plate strength and shell-to-base connection capacity. Towards this purpose, base uplifting mechanics is analyzed through a detailed simulation of the tank using non-linear finite elements, and a static pushover analysis is conducted that considers the hydrodynamic pressure distribution due to seismic loading on the tank wall and the base plate. The uplifting provisions from EN 1998-4 and API 650 Appendix E standards are briefly described. Numerical results for a typical 27.8-meter-diameter steel tank are compared with the above design provisions.

scholarly journals Calibration of Numerical Simulation Methods for Underwater Explosion with Centrifugal Tests

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Qiusheng Wang ◽  
Shicong Liu ◽  
Haoran Lou
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Peak Pressure ◽  
Bubble Radius ◽  
Three Dimensional ◽  
Underwater Explosion ◽  
Mesh Size ◽  
State Equation ◽  
Pulsation Period ◽  
Bubble Pulsation

The centrifugal underwater explosion tests and corresponding numerical simulations were carried out to study the laws of shock wave and bubble pulsation. A semiempirical method to determine JWL state equation parameters was given. The influence on numerical results caused by factors such as state equation of water, boundary condition, and mesh size was analyzed by comparing with the centrifugal underwater explosion test results. The results show that the similarity criterion is also suitable in numerical simulation; the shock wave peak pressure calculated by polynomial state equation is smaller than that of shock state equation. However, the maximum bubble radius and the pulsation period calculated by the two equations are almost the same. The maximum bubble radius is mainly affected by the boundary simulating the test model box, and the pulsation period is mainly affected by the artificial cutoff boundary. With the increase of standoff distance of measuring point, the mesh size required for the numerical calculation decreases; the size of the two-dimensional model is recommended to take 1/30 ∼ 1/10 explosion radius. In three-dimensional models, when mesh size is 2 times larger than explosion radius, the bubble motion change in the second pulsation period is not obvious. When mesh size is smaller than 1 time explosive radius, the full period of bubble pulsation can be well simulated, but calculation errors increase slowly and computation time greatly increases, so the three-dimensional mesh size is suggested to take the charge radius. Shock wave peak pressure is basically unaffected by gravity. As the gravity increases, the bubble maximum radius and the first pulsation period both decrease.

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