A Quasi-Vehicle/Bridge Interaction Model for High Speed Railways

2015 ◽  
Vol 31 (2) ◽  
pp. 217-225 ◽  
Author(s):  
J.-D. Yau ◽  
L. Frýba
Keyword(s):  
High Speed ◽  
Equations Of Motion ◽  
Interaction Model ◽  
Time History ◽  
Time Step ◽  
Moving Vehicle ◽  
Coupled Equations ◽  
History Analysis ◽  
High Speed Trains ◽  
Parametric Studies

ABSTRACTVehicle response is served as a reference to evaluate riding comfort of passengers and running safety of moving carriages for high speed trains. In analyzing the vehicle-bridge interaction (VBI) problems, two sets of coupled equations of motion for running vehicles and bridge need to be solved and the VBI system matrices must be updated and factorized at each time step in a time-history analysis. This paper proposed a quasi-VBI model to abridge the complicated computational process, in which the bridge is subjected to only moving static forces of the train loadings, and the moving vehicle over it is excited by the corresponding feedback bridge response. To examine the interacting degree of the vehicle with the bridge, a coupling evaluation index (CEI) is defined as a quantitative assessment of the VBI system. The numerical parametric studies reveal that (1) the mass ratio of vehicle to bridge is the most sensitive parameter affecting the bridge response; (2) increasing bridge damping can reduce the coupling degree of the VBI system at high speeds; (3) the present quasi-VBI model is an efficient and simple tool to predict the vehicle's response with enough accuracy based on engineering approximation.

Supplemental dampers in base-isolated buildings to mitigate large isolator displacement under earthquake excitations

2015 ◽  
Vol 48 (2) ◽  
pp. 100-117 ◽  
Author(s):  
Daniel H. Zelleke ◽  
Said Elias ◽  
Vasant A. Matsagar ◽  
Arvind K. Jain
Keyword(s):  
Equations Of Motion ◽  
Time History ◽  
Coupled Equations ◽  
History Analysis ◽  
Base Isolator ◽  
Fixed Base ◽  
Passive Dampers ◽  
Supplemental Dampers ◽  
Isolation Systems ◽  
Storey Building

The effect of viscous, viscoelastic, and friction supplemental dampers on the seismic response of base-isolated building supported by various isolation systems is investigated. Although base-isolated buildings have an advantage in reducing damage to the superstructure, the displacement at the isolation level is large, especially under near-fault ground motions. The influence of supplemental dampers in controlling the isolator displacement and other responses of base-isolated building is investigated using a multi-storey building frame. The coupled equations of motion are derived, solved and time history analysis is carried out on a building modeled with fifteen combinations of five isolation systems and three passive dampers. The seismic responses are compared with that of the fixed-base and base-isolated buildings. Based on the results, it is concluded that supplemental dampers are beneficial to control the large deformation at the isolator level. Parametric study is conducted and optimum ranges of damper parameters to achieve reduced isolator displacement without adverse effect on the other responses are determined. Further, it is concluded that the combination of the resilient-friction base isolator (R-FBI) and viscous damper is the most effective in reducing the bearing displacement without significant increase in superstructure forces.

Melnikov-based analysis for chaotic dynamics of spin-orbit motion of a gyrostat satellite

2019 ◽  
Vol 233 (4) ◽  
pp. 931-941
Author(s):  
Seyed Mahdi Abtahi
Keyword(s):  
Equations Of Motion ◽  
Time History ◽  
Melnikov Method ◽  
Spin Orbit ◽  
Attitude Dynamics ◽  
Inertia Moment ◽  
Coupled Equations ◽  
Highly Nonlinear ◽  
Complex Spin ◽  
The Mathematical Model

Interactions of the orbital motion on attitude dynamics of the gyrostat satellite are considered in this paper. The mathematical model is derived using the Hamiltonian method for the spin-orbit motion of the spacecraft followed by the reduction of the coupled equations of motion using the extended Deprit canonical transformation. The analytical Melnikov method is used innovatively to study chaos on the complex Spin-Orbit dynamics of the gyrostat satellite. Also, the numerical methods such as Lyapunov exponent criterion, Poincaré section, trajectories of phase portrait, and the time–history responses can be proved the heteroclinic bifurcation and chaotic vibrations in the highly nonlinear system. Using the results based on the Melnikov integral, the parameters of the spacecraft including the mass and inertia moment of satellite with respect to the altitude of orbit can be designed in order to control the bifurcation with a view to prevention of chaos in the system in the absence of an active control system.

Basic Study on the Seismic Response of the High-Speed-Moving Vehicle Considering Passengers' Dynamics

2012 ◽  
Vol 452-453 ◽  
pp. 1200-1204
Author(s):  
Atsuhiko Shintani ◽  
Tomohiro Ito ◽  
Yudai Iwasaki
Keyword(s):  
High Speed ◽  
Equations Of Motion ◽  
Seismic Excitations ◽  
Lagrangian Equation ◽  
Basic Study ◽  
Moving Vehicle ◽  
Seismic Input ◽  
The Stability ◽  
Risk Rate ◽  
Two Degree Of Freedom

The stability of the high-speed running vehicle subjected to seismic excitations considering passengers' dynamics are considered. A vehicle consists of one body, two trucks and four wheel sets. A passenger is modeled by simple two degree of freedom vibration system. The equations of motion of the vehicle and passengers are calculated by Lagrangian equation of motion. Combining two models, the behavior of the vehicle subjected to actual seismic input considering passengers' dynamics are calculated by numerical simulation. The stability of the vehicle is evaluated by using the risk rate of rollover. We investigate the possibility of the rollover of the vehicle. We focus on the effect of the dynamic characteristics of the human and the number of the passengers when the vehicle is subjected to the seismic excitation.

Analysis of Seismic Dynamic Response of Tunnel in Karst Areas

2011 ◽  
Vol 90-93 ◽  
pp. 2108-2111
Author(s):  
Lin Jie Chen ◽  
Bo Liang ◽  
Zhi Yong Wang
Keyword(s):  
Dynamic Response ◽  
Soil Structure ◽  
Interaction Model ◽  
Time History ◽  
Side Wall ◽  
Internal Force ◽  
Dynamic Responses ◽  
Karst Caves ◽  
History Analysis ◽  
Karst Areas

Based on soil-structure interaction model, the seismic dynamic response of tunnel in karst areas were performed by using viscous-spring artificial boundary and time history analysis method. In combination with the Menglian tunnel engineering on the Bao-Teng Highway in Yunnan, in different sizes and sites karst caves conditions, the dynamic responses of displacement and internal force on control points of the tunnel structure were obtained. The results show that comparatively large interal forces, under the high-intensity earthquake conditions, will appear on the side wall of the tunnel which through karst areas, less ones on arch crown and inverted arch parts, and the differential displacements of arch crown reach to the maximum. When the karst caves are located in the side of the tunnel, it make the seismic dynamic response get more large, which make the surrounding rock must be strengthened treatment. The results provide useful reference for the aseismatic design of tunnel.

Periodic Motions of a Two-Body System Subjected to Repetitive Impact

1969 ◽  
Vol 91 (4) ◽  
pp. 931-938 ◽  
Author(s):  
David L. Sikarskie ◽  
Burton Paul
Keyword(s):  
Steady State ◽  
High Speed ◽  
Equations Of Motion ◽  
Point Of View ◽  
State Behavior ◽  
State Response ◽  
Stability Of Solution ◽  
Straightforward Method ◽  
Parametric Studies ◽  
Repetitive Impact

The dynamics of a widely used class of hammer impact machines are investigated on the basis of a two-degree-of-freedom idealization. The difficulty in the problem is due to the repetitive impact which introduces a nonlinearity in the system. It is the purpose of the analysis to develop a solution for the steady-state behavior of the system. There are several ways this can be done. One of the most efficient ways, from the point of view of ease of parametric studies of the system, is to convert the problem to a “boundary” value problem. With this technique, the system is governed by the equations of motion between impacts, and further satisfies additional conditions at the beginning and end of each impact cycle. Since the solution is obtained in only one cycle, it thus represents a straightforward method of studying the effect of various system parameters. A fundamental assumption in the analysis is that the steady-state response of the system has a period equal to the forcing period. This is verified for one set of parameters through the use of high-speed movies of an actual machine. There are several other interesting features in the analysis, including multivaluedness of the solution, allowable solution domain, and stability of solution, which have not been completely resolved to date.

scholarly journals Sensor data-based probabilistic monitoring of time-history deflections of railway bridges induced by high-speed trains

2022 ◽  
pp. 147592172110634
Author(s):  
Jaebeom Lee ◽  
Seunghoo Jeong ◽  
Junhwa Lee ◽  
Sung-Han Sim ◽  
Kyoung-Chan Lee ◽  
...  
Keyword(s):  
High Speed ◽  
Time History ◽  
Training Data ◽  
Sensor Data ◽  
Data Synchronization ◽  
Speed Estimation ◽  
Railway Bridges ◽  
Monitoring Model ◽  
High Speed Trains ◽  
Probabilistic Monitoring

Structural condition monitoring of railway bridges has been emphasized for guaranteeing the passenger comfort and safety. Various attempts have been made to monitor structural conditions, but many of them have focused on monitoring dynamic characteristics in frequency domain representation which requires additional data transformation. Occurrence of abnormal structural responses, however, can be intuitively detected by directly monitoring the time-history responses, and it may give information including the time to occur the abnormal responses and the magnitude of the dynamic amplification. Therefore, this study suggests a new Bayesian method for directly monitoring the time-history deflections induced by high-speed trains. To train the monitoring model, the data preprocessing of speed estimation and data synchronization are conducted first for the given training data of the raw time-history deflection; the Bayesian inference is then introduced for the derivation of the probability-based dynamic thresholds for each train type. After constructing the model, the detection of the abnormal deflection data is proceeded. The speed estimation and data synchronization are conducted again for the test data, and the anomaly score and ratio are estimated based on the probabilistic monitoring model. A warning is generated if the anomaly ratio is at an unacceptable level; otherwise, the deflection is considered as a normal condition. A high-speed railway bridge in operation is chosen for the verification of the proposed method, in which a probabilistic monitoring model is constructed from displacement time-histories during train passage. It is shown that the model can specify an anomaly of a train-track-bridge system.

scholarly journals Structural Damping Effects on Dynamic Instability of Subtangentially Loaded and Shear Deformable Beck’s Columns

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Dong-Ju Min ◽  
Jaegyun Park ◽  
Sang-Ho Yeon ◽  
Moon-Young Kim
Keyword(s):  
Dynamic Instability ◽  
Time History ◽  
Linear Instability ◽  
Frequency Equation ◽  
Structural Damping ◽  
Damping Coefficients ◽  
Instability Theory ◽  
History Analysis ◽  
Stability Maps ◽  
Parametric Studies

A frequency equation of externally and internally damped and shear-flexible cantilever columns subjected to a subtangentially follower force is analytically derived in a dimensionless form with relation to the linear instability theory of Beck’s columns. Some parametric studies are then performed with variation of two damping coefficients under the assumption of Rayleigh damping. Based on the analysis results, it is demonstrated that three damping cases in association with flutter loads of Beck’s columns can be selected including one case representative of structural damping. Finally, stability maps of shear-flexible and damped Beck’s columns are constructed for the three damping cases and discussed in the practical range of damping coefficients and shear parameters. In addition, flutter loads and time history analysis results are presented using dimensionless FE analysis and compared with exact solutions.

High-Speed Vehicle Models Based on a New Concept of Vehicle/Structure Interaction Component: Part I—Formulation

1993 ◽  
Vol 115 (1) ◽  
pp. 140-147 ◽  
Author(s):  
L. Vu-Quoc ◽  
M. Olsson
Keyword(s):  
Nonlinear Equations ◽  
Building Block ◽  
High Speed ◽  
Equations Of Motion ◽  
Interaction Model ◽  
Component Part ◽  
Structure Interaction ◽  
Vehicle Structure ◽  
Interaction Component ◽  
High Speed Vehicle

High-speed vehicle/structure models constructed based on a new formulation of dynamic interaction between high-speed vehicles and flexible guideways are presented. A basic vehicle/structure interaction model forms a basic building block of complex vehicle/structure models in which lumped-parameter sub-components of the vehicle component (e.g., suspended masses with springs and dashpots) are assembled onto the basic vehicle/structure interaction component. A vertical and an inclined vehicle models are formulated. These vehicle models can serve as yet more advanced building-block models in the hierarchical construction of complex vehicle/structure models. The inclined vehicle model can be used to study the effects of braking of high-speed vehicles of flexible guideways. Fully nonlinear equations of motion of both models are given. Upon introducing approximations to the nonlinear kinematics, mildly nonlinear equations with an unusual mathematical structure are consistently derived. These equations are appropriate for use under realistic working conditions of the system, and are particularly amenable for numerical treatment using a recently proposed class of predictor/corrector algorithms.

Analytical Exploration of the Time History Analysis of Shock Response

2002 ◽  
Author(s):  
Shuenn-Yih Chang
Keyword(s):  
External Force ◽  
Time History ◽  
Small Time ◽  
Relative Amplitude ◽  
Time Step ◽  
Numerical Accuracy ◽  
Amplitude Error ◽  
History Analysis ◽  
Shock Response ◽  
Relative Period

It was experienced that a very small time step may be needed in the solution of the shock response from an impulse. In fact, this time step might be much smaller than the time step to have accurate representation of the impulse and negligible period distortion. It is theoretically verified that this difficulty is arising from the discontinuity in external force at the end of an impulse. In addition, a technique to estimate the relative amplitude error caused by this discontinuity is also developed. In fact, the accuracy of the shock response from a linear impulse is thoroughly explored both in amplitude and in period. Analytical results show that the accuracy is almost entirely dominated by the relative amplitude error tbr the impulse with significant discontinuity in external force at the end of the loading duration. Meanwhile, for the impulse without any discontinuity numerical accuracy is controlled by the relative period error in the solution of the shock response. Finally, guidelines to have accurate shock response from an impulse are proposed.

Dynamic Interactions of a High-Speed Vehicle and a Distributed Discretely Supported Guideway

2010 ◽  
Vol 26 (1) ◽  
pp. N9-N16
Author(s):  
C.-Y. Hu ◽  
K.-C. Chen ◽  
J.-S. Chen
Keyword(s):  
High Speed ◽  
Integration Method ◽  
Equations Of Motion ◽  
Dynamic Interactions ◽  
Coupled Equations ◽  
Steady State Responses ◽  
Loading Modes ◽  
Rigid Supports ◽  
State Responses ◽  
High Speed Vehicle

AbstractThis study investigates the dynamic interactions between a vehicle and guideway of a high-speed ground transportation system based on maglev vehicles. The guideway is assumed to be made up of identical simply supported beams with single spans and rigid supports. The vehicle is considered to a two-dimensional vehicle model with primary and secondary suspensions. Three kinds of loading modes acting at each beam of guideway are first developed according to the locations of suspensions of vehicle. Coupled equations of motion of both vehicle and guideway in various loading modes are derived and solved by using numerical integration method. The simulations have been performed to investigate the parameters of vehicle/guideway system which may affect the steady-state responses of the vehicle and guideway.

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