Dynamic Responses of a Four-Span Continuous Plate Structure Subjected to Moving Cars With Time-Varying Speeds

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Jing Yang ◽  
Huajiang Ouyang ◽  
Dan Stancioiu ◽  
Shancheng Cao ◽  
Xuhui He
Keyword(s):  
Theoretical Model ◽  
Dynamic Response ◽  
Laser Doppler Vibrometer ◽  
Dynamic Responses ◽  
Fe Model ◽  
Structural Dynamic ◽  
Plate Structure ◽  
In Series ◽  
Displacement Transducers ◽  
Continuous Plate

This paper presents an experimental and theoretical study of vibration of a four-span continuous plate with two rails on top and four extra supports excited by one or two moving model cars, which is meant to represent vehicle–track–bridge dynamic interaction. Measured natural frequencies of the plate structure are used to update the finite element (FE) model of the structure. Four laser displacement transducers are placed on the ground to measure the displacements of the plate. A laser-Doppler vibrometer is used to measure the real-time speed of the moving cars, which reveals that the speeds decrease with time at a small and almost constant deceleration which can affect the structural dynamic response. A fascinating experiment is the use of two cars connected in series, which is very rare and has never been done on a multispan structure. Vibration of the plate structure excited by two moving cars separated at a distance is also measured and exhibits interesting dynamic behavior too. A theoretical model of the whole structure is constructed and an iterative method is developed to determine the dynamic response. The numerical and the experimental results are found to agree very well, in particular when deceleration is considered in the theoretical model.

scholarly journals Dynamic response of a cable-stayed footbridge to high-energy mining tremors

2019 ◽  
Vol 106 ◽  
pp. 01022
Author(s):  
Izabela Drygała ◽  
Joanna M. Dulinska ◽  
Maria Anna Polak ◽  
Marek Wazowski
Keyword(s):  
Dynamic Response ◽  
High Energy ◽  
Mining Activity ◽  
Dynamic Responses ◽  
Fe Model ◽  
Coal Basin ◽  
Kinematic Excitation ◽  
Upper Silesian Coal Basin ◽  
Mining Tremors ◽  
Standard Software

In this work an analysis of the dynamic response of a cable-stayed footbridge to mining tremors typical for two main regions of mining activity in Poland, i.e. the Legnica-Glogow Copper District (LGCD) and the Upper Silesian Coal Basin (USCB) is presented. For analysis, a 3-D finite element (FE) model of the structure was created in the ABAQUS/Standard software program. As a final result, the dynamic responses of the footbridge to the typical mining tremors were delivered. For this stage, the numerical simulations were conducted with the non-uniform kinematic excitation as well as with the uniform kinematic excitation. Finally, the evaluation of two calculation approaches was also made for the studied structure.

Dynamic response of soil–pile–structure system subjected to lateral spreading: shaking table test and parallel finite element simulation

2020 ◽  
Vol 57 (4) ◽  
pp. 497-517 ◽  
Author(s):  
Lei Su ◽  
Hua-Ping Wan ◽  
Shaghayegh Abtahi ◽  
Yong Li ◽  
Xian-Zhang Ling
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Shaking Table Test ◽  
Lateral Spreading ◽  
Shaking Table ◽  
Dynamic Responses ◽  
Fe Model ◽  
System Parameters ◽  
Quay Wall ◽  
Parallel Finite Element

This paper investigates the dynamic response of soil–pile–structure interaction (SPSI) system behind a quay wall in liquefiable soil and laterally spreading ground through both large-scale shaking table test and parallel finite element (FE) simulation. A three-dimensional (3D) nonlinear FE model is developed to simulate the target SPSI system using the parallel modeling technique with high computational efficiency. This FE model of the SPSI system is validated by the shaking table test results. The validated FE model is firstly used to further explore the dynamic behavior of the SPSI system with details on the global responses of the SPSI system and the local responses. Secondly, the validated FE model is used for global sensitivity analysis (GSA) to fully assess the effects of uncertain parameters on the interested dynamic responses of the SPSI system. The experimental and numerical investigations show that liquefaction-induced lateral spreading significantly affects the movement of the clay crust at the landside and the internal forces in piles behind the quay wall. GSA results show that the relative importance of system parameters depends on the dynamic responses of interest, while the interaction effects among system parameters on dynamic responses are not evident.

Interval dynamic response analysis of structures with interval parameters

2008 ◽  
Vol 222 (3) ◽  
pp. 377-385 ◽  
Author(s):  
W Gao ◽  
N Zhang ◽  
J Ma ◽  
X B Wang
Keyword(s):  
Dynamic Response ◽  
Structural Parameters ◽  
Dynamic Responses ◽  
Truss Structures ◽  
Response Analysis ◽  
Superposition Method ◽  
Structural Dynamic ◽  
Dynamic Response Analysis ◽  
Interval Parameters ◽  
Mode Superposition Method

Dynamic response analysis of truss structures with interval parameters under interval loads are investigated using a new method called the interval factor method (IFM). Using the IFM, the structural physical parameters, geometric dimensions, and loads can be considered as interval variables. The structural stiffness and mass matrices can then, respectively, be described by the product of two parts corresponding to the deterministic matrix and the interval factors of structural parameters. The computational expressions for the midpoint value, lower and upper bounds of the structural dynamic responses are derived by means of the mode superposition method and interval operations. The influences of the uncertainty of the structural parameters and loads on the structural dynamic responses are demonstrated by using truss structures.

scholarly journals Dynamic response signatures of a scaled model platform for floating wind turbines in an ocean wave basin

2015 ◽  
Vol 373 (2035) ◽  
pp. 20140078 ◽  
Author(s):  
V. Jaksic ◽  
R. O'Shea ◽  
P. Cahill ◽  
J. Murphy ◽  
D. P. Mandic ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Control Strategies ◽  
Laser Doppler Vibrometer ◽  
Wind Farms ◽  
Recognition System ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Scaled Model ◽  
Wave Basin ◽  
Output Only

Understanding of dynamic behaviour of offshore wind floating substructures is extremely important in relation to design, operation, maintenance and management of floating wind farms. This paper presents assessment of nonlinear signatures of dynamic responses of a scaled tension-leg platform (TLP) in a wave tank exposed to different regular wave conditions and sea states characterized by the Bretschneider, the Pierson–Moskowitz and the JONSWAP spectra. Dynamic responses of the TLP were monitored at different locations using load cells, a camera-based motion recognition system and a laser Doppler vibrometer. The analysis of variability of the TLP responses and statistical quantification of their linearity or nonlinearity, as non-destructive means of structural monitoring from the output-only condition, remains a challenging problem. In this study, the delay vector variance (DVV) method is used to statistically study the degree of nonlinearity of measured response signals from a TLP. DVV is observed to create a marker estimating the degree to which a change in signal nonlinearity reflects real-time behaviour of the structure and also to establish the sensitivity of the instruments employed to these changes. The findings can be helpful in establishing monitoring strategies and control strategies for undesirable levels or types of dynamic response and can help to better estimate changes in system characteristics over the life cycle of the structure.

scholarly journals Effects of the Earthquake Nonstationary Characteristics on the Structural Dynamic Response: Base on the BP Neural Networks Modified by the Genetic Algorithm

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 69
Author(s):  
Yunlong Zhang ◽  
Dongsheng Du ◽  
Sheng Shi ◽  
Weiwei Li ◽  
Shuguang Wang
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Neural Networks ◽  
Dynamic Response ◽  
Earthquake Engineering ◽  
Bp Neural Network ◽  
Dynamic Responses ◽  
Training Data ◽  
Structural Dynamic ◽  
New Perspective

The intensity non-stationarity is one of the basic characteristics of ground motions, the influences of which on the dynamic responses of structures is a pressing issue in the field of earthquake engineering. The BP neural network modified by the genetic algorithm was adopted in this research to investigate the influence of intensity nonstationary inputs on the structural dynamic responses from a new perspective. Firstly, many training data were generated from the prediction formula of dynamic response. The BP neural network was then pre-trained by sparsely selected data to optimize the initial weights and biases. Finally, the BP neural network was trained by all data, and the mean square error of predicted responses compared with the target response were less than 10−5. The calculation formula of sensitivity was also derived here to quantify the influence of the input change on the output. The presented method combines the advantages of neural networks in nonlinear multi-variable fitting and provides a new perspective for the study of earthquake nonstationary characteristics and their influence on the structural dynamic responses.

Probabilistic analyses of structural dynamic response with modified Kriging-based moving extremum framework

2021 ◽  
Vol 125 ◽  
pp. 105398
Author(s):  
Cheng Lu ◽  
Cheng-Wei Fei ◽  
Yun-Wen Feng ◽  
Yong-Jun Zhao ◽  
Xiao-Wei Dong ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Structural Dynamic

Wind tunnel tests and dynamic analysis of wind-induced response of a transmission tower on a hill

2021 ◽  
pp. 136943322110339
Author(s):  
Jian Guo ◽  
Changliang Xiao ◽  
Jiantao Li
Keyword(s):  
Wind Tunnel ◽  
Wind Field ◽  
Dynamic Responses ◽  
Interactive Effects ◽  
Induced Response ◽  
Transmission Tower ◽  
Structural Dynamic ◽  
Wind Tunnel Tests ◽  
Hill Slope ◽  
The Hill

A hill with a lattice transmission tower presents complex wind field characteristics. The commonly used computational fluid dynamics (CFD) simulations are difficult to analyze the wind resistance and dynamic responses of the transmission tower due to structural complexity. In this study, wind tunnel tests and numerical simulations are conducted to analyze the wind field of the hill and the dynamic responses of the transmission tower built on it. The hill models with different slopes are investigated by wind tunnel tests to measure the wind field characteristics, such as mean speed and turbulence intensity. The study shows that the existence of a transmission tower reduces the wind speed on the leeward slope significantly but has little effect on the windward slope. To study the dynamic behavior of the transmission tower, a hybrid analysis procedure is used by introducing the measured experimental wind information to the finite element tower model established using ANSYS. The effects of hill slope on the maximum displacement response of the tower are studied. The results show that the maximum value of the response is the largest when the hill slope is 25° compared to those when hill slope is 15° and 35°. The results extend the knowledge concerning wind tunnel tests on hills of different terrain and provide a comprehensive understanding of the interactive effects between the hill and existing transmission tower regarding to the wind field characteristics and structural dynamic responses.

Model Test and Numerical Analysis of an Offshore Bottom Fixed Pentapod Wind Turbine Under Seismic Loads

2016 ◽  
Author(s):  
Wenhua Wang ◽  
Zhen Gao ◽  
Xin Li ◽  
Torgeir Moan ◽  
Bin Wang
Keyword(s):  
Wind Turbine ◽  
Wind Wave ◽  
Seismic Analysis ◽  
Wind Farms ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Test Model ◽  
Structural Dynamic ◽  
Load Conditions

In the last decade the wind energy industry has developed rapidly in China, especially offshore. For a water depth less than 20m, monopile and multi-pile substructures (tripod, pentapod) are applied widely in offshore wind farms. Some wind farms in China are located in high seismicity regions, thus, the earthquake load may become the dominant load for offshore wind turbines. This paper deals with the seismic behavior of an offshore wind turbine (OWT) consisting of the NREL 5MW baseline wind turbine, a pentapod substructure and a pile foundation of a real offshore wind turbine in China. A test model of the OWT is designed based on the hydro-elastic similarity. Test cases of different load combinations are performed with the environmental conditions generated by the Joint Earthquake, Wave and Current Simulation System and the Simple Wind Field Generation System at Dalian University of Technology, China, in order to investigate the structural dynamic responses under different load conditions. In the tests, a circular disk is used to model the rotor-nacelle system, and a force gauge is fixed at the center of the disk to measure the wind forces during the tests. A series of accelerometers are arranged along the model tower and the pentapod piles, and strain gauges glued on the substructure members are intended to measure the structural dynamic responses. A finite element model of the complete wind turbine is also established in order to compare the theoretical results with the test data. The hydro-elastic similarity is validated based on the comparison of the measured dynamic characteristics and the results of the prototype modal analysis. The numerical results agree well with the experimental data. Based on the comparisons of the results, the effect of the wind and sea loads on the structural responses subjected to seismic is demonstrated, especially the influence on the global response of the structure. It is seen that the effect of the combined seismic, wind, wave and current load conditions can not be simply superimposed. Hence the interaction effect in the seismic analysis should be considered when the wind, wave and current loads have a non-negligible effect.

Sign in / Sign up

Export Citation Format

Share Document