scholarly journals Running Safety of Trains under Vessel-Bridge Collision

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Yongle Li ◽  
Jiangtao Deng ◽  
Bin Wang ◽  
Chuanjin Yu
Keyword(s):  
Element Model ◽  
Dynamic Responses ◽  
Lateral Acceleration ◽  
Vertical Acceleration ◽  
Running Safety ◽  
Derailment Coefficient ◽  
Parametric Studies ◽  
Train Speed ◽  
Unloading Rate ◽  
Bridge System

To optimize the sensor placement of the health monitoring system, the dynamic behavior of the train-bridge system subjected to vessel-collision should be studied in detail firstly. This study thus focuses on the characteristics of a train-bridge system under vessel-bridge collision. The process of the vessel-bridge collision is simulated numerically with a reliable finite element model (FEM). The dynamic responses of a single car and a train crossing a cable-stayed bridge are calculated. It is shown that the collision causes significant increase of the train’s lateral acceleration, lateral wheelset force, wheel unloading rate, and derailment coefficient. The effect of the collision on the train’s vertical acceleration is much smaller. In addition, parametric studies with various train’s positions, ship tonnage, and train speed are performed. If the train is closer to the vessel-bridge collision position or the ship tonnage is larger, the train will be more dangerous. There is a relatively high probability of running danger at a low speed, resulting from longer stay of the train on the bridge. The train’s position, the ship tonnage, and the train speed must be considered when determining the most adverse conditions for the trains running on bridges under vessel-bridge collision.

Dynamic analysis of coupled train–track–bridge system subjected to debris flow impact

2018 ◽  
Vol 22 (4) ◽  
pp. 919-934 ◽  
Author(s):  
Xun Zhang ◽  
Zhipeng Wen ◽  
Wensu Chen ◽  
Xiyang Wang ◽  
Yan Zhu
Keyword(s):  
Debris Flow ◽  
Dynamic Analysis ◽  
High Speed ◽  
Impact Load ◽  
Dynamic Responses ◽  
Train Track ◽  
Running Safety ◽  
Track Bridge ◽  
Safety Indices ◽  
Bridge System

With the increasing popularity of high-speed railway, more and more bridges are being constructed in Western China where debris flows are very common. A debris flow with moderate intensity may endanger a high-speed train traveling on a bridge, since its direct impact leads to adverse dynamic responses of the bridge and the track structure. In order to address this issue, a dynamic analysis model is established for studying vibrations of coupled train–track–bridge system subjected to debris flow impact, in which a model of debris flow impact load in time domain is proposed and applied on bridge piers as external excitation. In addition, a six-span simply supported box girder bridge is considered as a case study. The dynamic responses of the bridge and the running safety indices such as derailment factor, offload factor, and lateral wheel–rail force of the train are investigated. Some influencing factors are then discussed based on parametric studies. The results show that both bridge responses and running safety indices are greatly amplified due to debris flow impact loads as compared with that without debris flow impact. With respect to the debris flow impact load, the boulder collision has a more negative impact on the dynamic responses of the bridge and train than the dynamic slurry pressure. Both the debris flow impact intensity and train speed determine the running safety indices, and the debris flow occurrence time should be also carefully considered to investigate the worst scenario.

scholarly journals Vertical Dynamic Analysis of Ballastless Tracks on Train-Track- Bridge System

2020 ◽  
Vol 306 ◽  
pp. 02003
Author(s):  
Haoran Xie ◽  
Bin Yan ◽  
Jie Huang
Keyword(s):  
Track Structure ◽  
Vertical Acceleration ◽  
Train Track ◽  
Steel Spring ◽  
Slab Track ◽  
Ballastless Track ◽  
Track System ◽  
Train Speed ◽  
Track Bridge ◽  
Bridge System

In order to investigate the vertical dynamic response characteristics of train-track-bridge system on CWR (Continunously Welded Rail) under dynamic load of train on HSR (High-Speed Railway) bridge. Based on the principle of vehicle train-track-bridge coupling dynamics, taking the 32m simply supported bridge of a section of Zhengzhou-Xuzhou Passenger Dedicated Line as an example, the finite element software ANSYS and the dynamic analysis software SIMPACK are used for co-simulation, and bridge model of the steel spring floating slab track and the CRTSIII ballastless track (China Railway Track System) considering the shock absorbing steel spring, the limit barricade and the contact characteristics of track structure layers are established. On this basis, in order to study the dynamic response laws of the design of ballastless track structure parameters to the system when the train crosses the bridge and provide the basis for the design and construction, by studying the influence of the speed of train on the bridge, the damage of fasteners and the parameters of track structure on the train-track-bridge system, the displacement of rail, vertical vibration acceleration and wheel-rail force response performance are analyzed. Studies have shown that: At the train speed of 40 km/h, the displacement and acceleration of the rail and track slab in the CRTSIII ballastless track are smaller than the floating slab track structure, but the floating slab track structure has better vibration reduction performance for bridges. The acceleration of rail, track slab and bridge increases obviously with the increase of train speed, the rail structure has the largest increasement. Reducing the stiffness of fasteners could decrease the vertical acceleration response of the steel spring floating slab track system, the ability to absorb shock can be enhanceed by reducing the stiffness of the fastener appropriately. Increasing the density of the floating slab can increase the vertical acceleration of the floating slab and the bridge, thereby decreasing the vibration amplitude of the system.

Study of Train Derailments Caused by Damage to Suspension Systems

2015 ◽  
Vol 11 (3) ◽  
Author(s):  
S. H. Ju
Keyword(s):  
Finite Element ◽  
Nonlinear Finite Element Method ◽  
Train Derailment ◽  
Interval Time ◽  
Suspension Systems ◽  
Derailment Coefficient ◽  
Parametric Studies ◽  
Train Speed ◽  
Rail Irregularities ◽  
Secondary Suspension

A nonlinear finite element method was used to investigate the derailments of trains moving on multispan simply supported bridges due to damage to suspension systems. At the simulation beginning, the initial vertical trainloads to simulate the train gravity weight are gradually added into the mass center of each rigid body in the train model with large system damping, so the initial fake vibration is well reduced. A suspension is then set to damage within the damage interval time, while the spring and/or damper changes from no damage to a given percentage of damage. Finite element parametric studies indicate the following: (1) the derailment coefficients of the wheel axis nearby the damage location are significantly increased. (2) Damage to the spring is more critical than that to the damper for the train derailment effect. (3) The derailment coefficient induced by damage to the primary suspension is more serious than that to the secondary suspension. (4) If rail irregularities are neglected, the train speed has little influence on the derailment coefficients generated from damage to suspensions. (5) The train derailment coefficients rise with a decrease in the damage interval time, so sudden damages to suspension systems should be avoided.

Experimental and numerical investigations of the dynamic responses of an asymmetrical arch railway bridge

2018 ◽  
Vol 232 (9) ◽  
pp. 2309-2323 ◽  
Author(s):  
Hongye Gou ◽  
Yannian He ◽  
Wen Zhou ◽  
Yi Bao ◽  
Genda Chen
Keyword(s):  
Ride Comfort ◽  
Three Dimensional ◽  
Element Model ◽  
Dynamic Responses ◽  
Dynamic Strain ◽  
Railway Bridge ◽  
Coupling System ◽  
Dimensional Finite Element ◽  
Train Speed ◽  
Three Dimensional Finite Element

The dynamic responses of an asymmetrical arch railway bridge subjected to moving trains are experimentally and numerically investigated in this study. The strains, displacements and accelerations at critical sections of the bridge were measured at different speeds of trains. A three-dimensional finite element model of the bridge–vehicle coupling system was established to understand the measured dynamic responses and was validated against the experimental results. The numerical model was used to analyze the influence of asymmetry on the dynamic responses of the bridge and the safety and ride comfort of trains. The results indicate that the dynamic responses of the bridge increase with the train speed. Braking of the train has the largest impact on the vertical dynamic displacement of the bridge. The maximum dynamic strain is in the arch rib. The longer half arch demonstrated much larger counterforce and dynamic responses than those of the shorter half arch, while the symmetrical structures tend to exhibit good symmetry. The asymmetrical arrangement of the bridge reduces the structural stiffness.

Seismic Design Research of Simply Supported Rail-Bridge Based on Running Safety

2014 ◽  
Vol 1065-1069 ◽  
pp. 962-968
Author(s):  
Yan Han ◽  
Xiao Dong Wang
Keyword(s):  
Seismic Design ◽  
Traffic Safety ◽  
Interpolation Method ◽  
Spectral Characteristics ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Analysis Model ◽  
Running Safety ◽  
Simply Supported ◽  
Bridge System

To explore the practical rail-bridge seismic design methods, dynamic response analysis model of the train-rail-bridge system under seismic loads was established, and the widely used simply supported track-bridge in rail transport was taken for the study. By inputting different intensity and frequency artificial seismic waves to the train-rail-bridge system, the whole history of the vehicles running through the bridge is simulated and the dynamic responses of the bridge and the vehicles are calculated. The influence of train type, seismic intensity and spectral characteristics of the earthquake were analyzed. Taking Japanese traffic safety evaluation indexes including derailment coefficient, wheel offload rate and lateral wheel-rail force as evaluation criteria, the allowed lateral bridge displacement limits and acceleration limits that ensuring train running safety under earthquake were obtained, and the bridge vibration limit curve was drawn. Using Lagrange interpolation method, the mathematical expression of the curve was worked out, which can provide a reference to rail-bridge aseismic design.

scholarly journals Numerical Analysis of a Train-Bridge System Subjected to Earthquake and Running Safety Evaluation of Moving Train

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Xun Yang ◽  
Huanhuan Wang ◽  
Xianlong Jin
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Three Dimensional ◽  
Safety Evaluation ◽  
Element Model ◽  
Earthquake Intensity ◽  
Running Safety ◽  
Simulation Problem ◽  
Moving Train ◽  
Bridge System

This paper investigates the dynamic response of a train-bridge system subjected to earthquakes, and the running safety indices of the train on the bridge under earthquake are studied. Taking a long span cable-stayed bridge across the Huangpu River as an example, a full three-dimensional finite element model of the train-bridge system was established, in which the soil-bridge and rail-train interactions were considered. Parallel computing based on contact balance was utilized to deal with this large-scale numerical simulation problem. The dynamic nonlinear analysis was performed on a Hummingbird supercomputer using the finite element code LS-DYNA 971. The results show that the acceleration responses of the train subjected to an earthquake are much greater than the ones without earthquake input, and the running safety of a moving train is affected by both the earthquake intensity and the running speed of the train. The running safety of the moving train can be evaluated by the threshold curve between earthquake intensity and train speed. The proposed modeling strategies and the simulated results can give a reference prediction of the dynamic behaviour of the train-bridge subjected to an earthquake.

Analysis of structural stresses of tracks and vehicle dynamic responses in train–track–bridge system with pier settlement

2016 ◽  
Vol 232 (2) ◽  
pp. 421-434 ◽  
Author(s):  
Zhaowei Chen ◽  
Wanming Zhai ◽  
Qiang Yin
Keyword(s):  
High Speed ◽  
Dynamic Responses ◽  
Vertical Acceleration ◽  
Vehicle Dynamic ◽  
Train Track ◽  
Slab Track ◽  
Structural Stresses ◽  
Track Bridge ◽  
Bridge System ◽  
Dynamic Indicators

Pier settlement causes deformation of bridge structures, and further distorts the track structures placed on bridge decks, which may greatly affect the service life of the tracks and safe operation of trains. This study analyzes track stresses and vehicle dynamic responses in train–track–bridge system with pier settlement and determines the pier settlement safe value for high-speed railways with China Railway Track System (CRTS) II slab tracks. First, a detailed train–track–bridge dynamic model is established based on the train–track–bridge dynamic interaction theory. Verified with field experimental results, the model is utilized to calculate the dynamic responses of the vehicle–track–bridge system with different pier settlement values. Finally, the safe value of the pier settlement in the CRTS II slab track railway line is determined according to the limit of the vehicle dynamic indicators and the structural stresses of tracks. The results show that the vertical acceleration of the car body is more sensitive to pier settlement among all the vehicle dynamic indicators. Structural stresses of tracks caused by pier settlement appear at the positions of the pier with settlement and its two adjacent piers. The effect of train loads on the track stresses is much smaller than that of the pier settlement. It is important to adopt the structural stresses of tracks as the evaluation criteria of the pier settlement safe value than the vehicle dynamic indicators. Taking the effects of the bridge pier settlement, the vehicle load, the prestress effect, and the self-weight into consideration, the pier settlement safe value for the high-speed railway lines with the CRTS II slab track is 11.5 mm.

Behaviour of Metro Coach on Newly Built Track in Kolkata

2020 ◽  
Author(s):  
Hrishikesh Gajanan Danawe ◽  
Sudhir Kumar Singh ◽  
Vikranth Racherla ◽  
Sanjay R. Singh ◽  
Arun Prasad
Keyword(s):  
Multibody Dynamics ◽  
Static Load ◽  
Field Trials ◽  
Lateral Acceleration ◽  
Vertical Acceleration ◽  
Dynamics Model ◽  
Vehicle Performance ◽  
Derailment Coefficient ◽  
Multibody Dynamics Model

Abstract This paper presents the behaviour of a new metro coach on a newly built track in Kolkata, India. Oscillation trials were conducted using LVDT sensors at different locations to monitor primary and secondary springs compression. Multibody dynamics model is built with actual parameters of coach and track in SIMPACK. The behaviour of the vehicle for given track with elevation and curvature changes has been studied. Vehicle performance has been evaluated based on safety, running behaviour and track fatigue mentioned in UIC 518. Results of primary and secondary spring compressions obtained from field trials and multibody dynamics model have been compared. Coach lateral and vertical acceleration, bogie lateral acceleration, static load at rail wheel contact and derailment coefficient obtained from the multibody dynamics model are discussed. Obtained results were within permission values. Scope of this paper lies in studying the vehicle performance in connection to safety and running behaviour of newly introduced metro in Kolkata.

Dynamic responses of a high-speed train passing a deformed bridge using a vehicle-track-bridge coupled model

2020 ◽  
pp. 095440972094433 ◽  
Author(s):  
Hongye Gou ◽  
Chang Liu ◽  
Wen Zhou ◽  
Yi Bao ◽  
Qianhui Pu
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Coupled Model ◽  
Element Model ◽  
Vertical Vibration ◽  
Dynamic Responses ◽  
High Speed Train ◽  
Railway Network ◽  
Track Bridge ◽  
Bridge System

With the development of the railway network in a harsh environment, the additional bridge deformations accumulated over time may endanger high-speed trains passing through a bridge, since the bridge deformation directly affect the geometry of the track on the bridge, thus affecting the dynamic responses of the train. This paper investigates the effects of different types of bridge deformation on the dynamic responses of the high-speed train passing through a deformed bridge. First, a finite element model is established for a high-speed railway bridge to study the dynamic responses of vehicle-track-bridge system under bridge deformations. Then, the rail deformation caused by bridge deformation is calculated using a bridge-track deformation mapping model, and used as the excitation to the vehicle-track-bridge system to study the influence of bridge deformations on the dynamic responses of the train. Results show that the vertical bridge deformations mainly affect the vertical vehicle dynamic indices, and have negligible effect on the lateral dynamic indices. The additional bridge deformation generates an additional low-frequency excitation to the train. The bridge deformations mainly affect the dynamic responses at specific characteristic frequencies, which are independent on the magnitude of the deformation. The frequencies for bridge deformations are magnified at about 1 Hz, indicating that the additional bridge deformation may aggravate the vertical vibration of the train.

Development of a Finite Element Model for Simulation of Rollover Crashes

2007 ◽  
Author(s):  
Jingwen Hu ◽  
Chunsheng Ma ◽  
King H. Yang ◽  
Clifford C. Chou ◽  
Albert I. King ◽  
...  
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Development Stage ◽  
Rigid Body Dynamics ◽  
Lateral Acceleration ◽  
Computational Time ◽  
Fe Model ◽  
Vertical Acceleration ◽  
Fe Method ◽  
Vehicle Crashworthiness

Rollover crashes are complex by their very nature, and have stimulated many researches aimed at improved occupant safety. In order to investigate the vehicle crashworthiness during rollovers, several test modes are generally used to replicate different real world rollover scenarios. However, such tests are very expensive, especially during the development stage of a new car line. Computer modeling is a cost-effective way to study rollover crashes. However, a survey of literature showed that only rigid-body dynamics based models have been used for rollover simulations. It is well known that this class of models cannot be used to simulate component deformation and structural collapses. Finite element (FE) method, which has been widely used to simulate frontal and side crashes, was rarely used for simulating rollover crashes, due mainly to the relative long duration of a rollover crash. The objective of this study was to develop an FE model for investigating vehicle crashworthiness during three commonly used rollover tests. An FE model of an SUV was developed in this study. Several sub-models, namely the vehicle structure sub-model, the tire sub-model, the suspension system sub-model, the restraint system sub-model, and the dummy model were generated and integrated together. The structure model was first used to simulate the roof crush test as prescribed in FMVSS 216. The resulting load versus roof crush curve matched well against test results. The integrated model was then used to simulate three laboratory-based rollover test modes, namely the SAE J2114 dolly test, curb-trip test, and corkscrew test. For each test mode, up to 1.5 seconds of simulation time (about 1 full vehicle roll) were computed. The vehicle kinematics, including the angular velocity, lateral acceleration, and vertical acceleration during these three test modes were computed and compared with experimental data. The simulated dummy head accelerations, timing and location of the most severe impact to the dummy’s head were also compared with the experimental results. Results showed very good agreement between the tests and simulations. In order to reduce the computational time, multiple CPUs were used. Approximately ten hours were required to run a 1.5 second rollover simulation on eight CPUs. Thus, simulating rollovers using FE method is quickly becoming a reality.

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