Dynamic Response Characteristics of Underground Powerhouse Caverns for Sandaowan Hydropower Station

2011 ◽  
Vol 382 ◽  
pp. 80-83 ◽  
Author(s):  
Zhen Zhong Shen ◽  
Hua Chun Ren
Keyword(s):  
Seismic Waves ◽  
Low Frequency ◽  
Time History ◽  
Element Model ◽  
Frequency Characteristics ◽  
Dynamic Responses ◽  
Principal Stresses ◽  
Underground Powerhouse ◽  
Response Characteristics ◽  
Set Up

According to the practical situation, the 3-D finite element model of Sandaowan underground powerhouse caverns on Taolai River is set up for analyzing the behaviors under earthquake action. Based on static stress field of the surrounding rock mass, and with the selection of appropriate seismic waves for dynamic time-history analysis method, the dynamic responses of underground powerhouse caverns are analyzed. It is shown that the time-history waveform of dynamic displacement of given points has a very similar variation regularity with that of acceleration, and the wave phases of both are almost synchronous. The dynamic displacements and principal stresses of the given points on rock walls are with the vibration of low-frequency characteristics, the acceleration response is with the vibration of high-frequency characteristics.

Time History Analysis of Seismic Response of Novel Core-Tube Vibration-Reduction Suspended Structures

2011 ◽  
Vol 243-249 ◽  
pp. 67-71
Author(s):  
Wei Zhang ◽  
Ji Wen Zhang ◽  
Yong Ming Tu
Keyword(s):  
Seismic Waves ◽  
Vibration Reduction ◽  
Time History ◽  
Bottom Layer ◽  
Element Model ◽  
Relative Displacement ◽  
Calculation Model ◽  
Dynamic Responses ◽  
Core Tube ◽  
Structure System

A novel building structure system, namely core-tube vibration-reduction suspended structure (CVRSS), is put forward in this paper. The basic composition and calculation model for the structure system are described. The El Centro and Taft seismic waves are used to calculate the dynamic characteristics of the structure in the time domain, of which dynamic responses are proved satisfactory. Taking the top floor displacement of the primary structure and the relative displacement between bottom layer of suspended segments and top floor of core-tube as objective function, the finite element model is established, and comparative analysis with common core-tube suspended structures (CCSS) is performed. The results show that the top floor displacement of CVRSS is about 70% of that of CCSS, and the vibration-reduction performance of CVRSS is excellent.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

Influence of Wave Passage Effect on Seismic Response of Truss String Structure Co-Working with its Base Frame

2014 ◽  
Vol 533 ◽  
pp. 154-158
Author(s):  
He Peng Wang ◽  
Zhong Gen Xu ◽  
Chang Gen Deng
Keyword(s):  
Seismic Waves ◽  
Time History ◽  
Element Model ◽  
Seismic Responses ◽  
Passage Effect ◽  
History Analysis ◽  
Insertion Method ◽  
String Structure ◽  
Wave Passage ◽  
Wave Passage Effect

By inputting two groups of seismic waves with phase differences of 0.16s, 0.34s, 0.5 and 0.34s, 0.66s, 1.0s to column elements divided into four parts of lower story of finite element model with insertion method, this paper analyzed the influence of wave passage effect on seismic responses of truss string structure of Guangzhou Convention and Exhibition Centre co-working with its base frame by time history analysis method. The results show that: because of natural vibration characteristics of structure, wave traveling has some effect on seismic responses of truss string structure of Guangzhou Convention and Exhibition Centre.

scholarly journals Vibration Response Characteristics of the Cross Tunnel Structure

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jinxing Lai ◽  
Kaiyun Wang ◽  
Junling Qiu ◽  
Fangyuan Niu ◽  
Junbao Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Time History ◽  
Element Model ◽  
Vibration Response ◽  
Shield Tunnel ◽  
Tunnel Structure ◽  
Response Characteristics ◽  
Vehicle Load ◽  
Metro Tunnel

It is well known that the tunnel structure will lose its function under the long-term repeated function of the vibration effect. A prime example is the Xi’an cross tunnel structure (CTS) of Metro Line 2 and the Yongningmen tunnel, where the vibration response of the tunnel vehicle load and metro train load to the structure of shield tunnel was analyzed by applying the three-dimensional (3D) dynamic finite element model. The effect of the train running was simulated by applying the time-history curves of vibration force of the track induced by wheel axles, using the fitted formulas for vehicle and train vibration load. The characteristics and the spreading rules of vibration response of metro tunnel structure were researched from the perspectives of acceleration, velocity, displacement, and stress. It was found that vehicle load only affects the metro tunnel within 14 m from the centre, and the influence decreases gradually from vault to spandrel, haunch, and springing. The high-speed driving effect of the train can be divided into the close period, the rising period, the stable period, the declining period, and the leaving period. The stress at haunch should be carefully considered. The research results presented for this case study provide theoretical support for the safety of vibration response of Metro Line 2 structure.

The Finite Element Model Determination in the Loess Regions under Subway Vibration Loads

2011 ◽  
Vol 368-373 ◽  
pp. 2586-2590
Author(s):  
Zhao Bo Meng ◽  
Shi Cai Cui ◽  
Teng Fei Zhao ◽  
Liu Qin Jin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Low Frequency ◽  
Time History ◽  
Ground Vibration ◽  
Element Model ◽  
Vibration Velocity

According to measured shear wave velocity of Xi’an Bell Tower area (Loess Area), the dynamic parameters of site soil are determined by using the relationship between shear wave velocity and compression wave velocity. Using Matlab program, the finite element size for low frequency subway vibration is obtained by analyzing soil dispersion phenomenon. On this basis, two-dimensional model with viscous - elastic boundaries is established by using the ANSYS program. The load-time history of the train is applied to the right tunnel, and the effects of the depth and breadth of the different models on the ground vibration velocity are discussed. Finally, the dimensions and element sizes of finite element model are obtained for the Xi'an No. 2 Metro Line with 15m depth in the loess regions.

Optimum Design of Structures for Earthquake Induced Loading by Wavelet Neural Network

2007 ◽  
pp. 80-100
Author(s):  
Eysa Salajegheh ◽  
Ali Heidari
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Dynamic Analysis ◽  
Optimum Design ◽  
Low Frequency ◽  
Time History ◽  
Wavelet Neural Network ◽  
Dynamic Responses ◽  
Frequency Content ◽  
Fast Wavelet

Optimum design of structures for earthquake induced loading is achieved by a modified genetic algorithm (MGA). Some features of the simulated annealing (SA) are used to control various parameters of the genetic algorithm (GA). To reduce the computational work, a fast wavelet transform is used. The record is decomposed into two parts. One part contains the low frequency of the record, and the other contains the high frequency of the record. The low-frequency content is used for dynamic analysis. Then using a wavelet neural network, the dynamic responses of the structures are approximated. By such approximation, the dynamic analysis of the structure becomes unnecessary in the process of optimisation. The wavelet neural networks have been employed as a general approximation tool for the time history dynamic analysis. A number of structures are designed for optimal weight and the results are compared to those corresponding to the exact dynamic analysis.

Dynamic Response Analysis of Tailings Dam under Seismic Action

2015 ◽  
Vol 799-800 ◽  
pp. 746-750
Author(s):  
Ai Min Gong ◽  
Hai Yan Huang ◽  
Hui Ying Zhang
Keyword(s):  
Dynamic Stability ◽  
Time History ◽  
Reference Value ◽  
Element Model ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Seismic Load ◽  
Seismic Action ◽  
Tailings Dam ◽  
Dynamic Time

A finite element model of tailiings dam was used to analyze the dynamic responses of the stress field, displacement and acceleration of the dam with the dynamic time-history response analysis method in this paper. The time-history curves of different responses were obtained. And an evaluation for dynamic stability of the tailings dam was also discussed. The analysis result shows that this case can provide a certain reference value for the dynamic calculation and the dynamic stability analysis of tailings dam under seismic load.

scholarly journals Passive Control of a Pentapod Offshore Wind Turbine Under Earthquakes by Using Tuned Mass Damper

2017 ◽  
Author(s):  
Wenhua Wang ◽  
Zhen Gao ◽  
Xin Li ◽  
Torgeir Moan ◽  
Bin Wang
Keyword(s):  
Wind Turbine ◽  
Seismic Waves ◽  
Passive Control ◽  
Element Model ◽  
Tuned Mass Damper ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Mass Damper ◽  
And Control

The finite element model (FEM) of a pentapod offshore wind turbine (OWT) is established in the newly compiled FAST. The dynamic responses of the OWT are analyzed in detail. Further, a tuned mass damper as a passive control strategy is applied in order to reduce the OWT responses under seismic loads. The influence of the tuned mass damper (TMD) locations, mass and control frequencies on the reduction of OWT responses are investigated. A general configuration of TMD can effectively reduce the local and global responses to some degree, but due to the complexity of characteristics of the OWT structure and seismic waves, the single TMD can not obtain consistent controlling effects.

Seismic Response Reduction of Cable-Stayed Bridge with Viscous Dampers

2011 ◽  
Vol 137 ◽  
pp. 154-158
Author(s):  
Wen Liang Qiu ◽  
Meng Jiang ◽  
Xing Bo Zhang
Keyword(s):  
Seismic Waves ◽  
Time History ◽  
Longitudinal Direction ◽  
Element Model ◽  
Design Parameters ◽  
Longitudinal Displacement ◽  
Cable Stayed Bridge ◽  
History Analysis ◽  
Floating System ◽  
The Cost

For floating system cable-stayed bridge, the longitudinal displacement of girder and moments of towers are very large when strong earthquake happens. The dampers installed between girder and towers in longitudinal direction can reduce efficiently displacement of the girder and moments of the towers induced by longitudinal seismic waves. Using spatial finite element model and time history analysis method, the influences of design parameters of viscous damper on seismic responses of cable-stayed bridge are studied in detail. The results of study show that, with the damping constant increasing, the longitudinal displacement of girder and moment of tower decrease, and the forces of damper increase. With velocity exponent increasing, the longitudinal displacement of girder and moment of tower increase, and the force of damper decrease. So, when determining the design parameters of damper, the cost of dampers, difficulty of construction and seismic reduction effects should be considered together.

Research on the Earthquake Dynamic Responses of Tunnel under Changing Tunnel Lining Rigidity

2011 ◽  
Vol 250-253 ◽  
pp. 1978-1982
Author(s):  
Xiao Ping Cao
Keyword(s):  
Finite Element ◽  
Dynamic Load ◽  
Element Model ◽  
Tunnel Lining ◽  
Dynamic Responses ◽  
Seismic Responses ◽  
Set Up ◽  
Deeply Buried Tunnel ◽  
Element Theory ◽  
The Finite Element Model

With the increasing of the quantity of the tunnel, more and more attentions have been paid to the tunnel destruction induced by earthquake. Based on the software of finite element, the finite element model for deeply buried tunnel have been set up; and the responses about different rigidity of tunnel lining under seismic dynamic load has been analyzed by using elastic finite element theory. The conclusions have been drawn that the change of seismic responses by increasing rigidity of tunnel lining is unobvious, and the method using increasing rigidity of tunnel lining to reduce the seismic responses of tunnel is uneconomical.

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