Analytical Model to Predict Dynamic Responses of Railway Subgrade due to High-Speed Trains Considering Wheel–Track Interaction

2016 ◽  
Vol 16 (2) ◽  
pp. 04015061 ◽  
Author(s):  
Hailin Yao ◽  
Zhi Hu ◽  
Zheng Lu ◽  
Hua Wang
2019 ◽  
Vol 23 (3) ◽  
pp. 454-467
Author(s):  
Zhibin Jin ◽  
Ligang Yuan ◽  
Shiling Pei

The running safety of high-speed trains over bridges is a great concern in bridge design. Typically, the running safety of vehicles is evaluated by vehicle–track simulations that are computationally expensive and unfamiliar to bridge designers. This study investigates simplified vehicle–track models for assessing the running safety of vehicles on deformed bridges. Four types of simplified vehicle models along with four types of simplified wheel–track models are investigated. The predicted wheel–rail forces are compared with those simulated by the detailed vehicle–track program. In these simulations, typical bridge deformations are taken as excitations to the dynamic system. It is found that omitting the rail vibration leads to large wheel–rail response errors. The wheel–rail constraint model gives similar wheel–rail responses to those obtained by the Hertz contact model. A vehicle–track model with five degrees-of-freedom is adequate for assessing wheel–rail forces. Furthermore, an analytical solution to the wheel–rail forces running over an angular rotation was obtained. These simplified vehicle–track models provide an efficient way to assess the running safety of vehicles on deformed bridges when using probabilistic or optimal analyses that require a large number of simulations.


2020 ◽  
pp. 107754632093689
Author(s):  
Hongye Gou ◽  
Chang Liu ◽  
Hui Hua ◽  
Yi Bao ◽  
Qianhui Pu

Deformations of high-speed railways accumulate over time and affect the geometry of the track, thus affecting the running safety of trains. This article proposes a new method to map the relationship between dynamic responses of high-speed trains and additional bridge deformations. A train–track–bridge coupled model is established to determine relationship between the dynamic responses (e.g. accelerations and wheel–rail forces) of the high-speed trains and the track deformations caused by bridge pier settlement, girder end rotation, and girder camber. The dynamic responses are correlated with the track deformation. The mapping relationship between bridge deformations and running safety of trains is determined. To satisfy the requirements of safety and riding comfort, the suggested upper thresholds of pier settlement, girder end rotation, and girder camber are 22.6 mm, 0.92‰ rad, and 17.2 mm, respectively. This study provides a method that is convenient for engineers in evaluation and maintenance of high-speed railway bridges.


2013 ◽  
Vol 574 ◽  
pp. 135-150
Author(s):  
Jia Feng Liu ◽  
Yan Li

With the development of long-span flexible bridges and the increase of highway transportation, both the dynamic responses of highway bridges under high-speed and heavy vehicles and the safety control of vehicles have deserved general concerns. First, this paper briefly discussed some researches on coupling vibration of vehicle and highway-bridges, then roundly summarized main research achievements accounting on the vehicle analytical model, bridge analytical model, surface roughness of road, numerical method of vehicle-bridge coupling vibration and some other aspects. Meanwhile, some research trends and challenge on vehicle and bridge dynamic interaction in engineering application were pointed out.


Author(s):  
Zhiwei Wang ◽  
Paul Allen ◽  
Guiming Mei ◽  
Zhonghui Yin ◽  
Yao Cheng ◽  
...  

To analyse and simulate the dynamic responses of the gearbox in a vehicle–track system, a three-dimensional vehicle–track coupled dynamics model for high-speed trains has been developed in this study with a comprehensive consideration of the transmission system. Using this dynamics model, the coupling effects between the gearbox housing and its connected components were analysed. Based on the dynamic results, the dynamic stress field of the gearbox housing can be obtained using the finite element methods. The model outputs were successfully validated through comparisons with field test data. Following model validation, the dynamic stress and its distribution throughout the gearbox housing were further investigated under different excitations, including track irregularities, wheel polygonal wear and flatness. The results demonstrate a significant increase in the stress levels of the oil level window aperture and the bottom face of the housing, which coincides with the location of cracks that are formed in the gearbox housing during frequent vehicle operation. While a specific case has been studied here, the proposed dynamics model can be applied to related dynamic assessments, such as vibration or suspension parameter analyses, as well as to stress analyses of any rail vehicle transmission system to guide the maintenance and design.


2021 ◽  
Vol 263 (6) ◽  
pp. 434-441
Author(s):  
S.K. Lai ◽  
C. Wang ◽  
L.H. Zhang ◽  
Y.Q. Ni

The development of the worldwide high-speed rail network is expanding at a rapid pace, imposing great challenges on the operation safety. Recent advances in wireless communications and information technology can integrate the Internet of Things and cloud computing to form a real-time monitoring platform of high-speed trains. To realize this system, a sustainable power source is indispensable. In this case, an ideal solution is to deploy a vibration-based energy harvester instead of batteries for the electrical supply of wireless sensors/devices, as vibrations induced by rail/wheel contact forces and vehicle dynamics are an abundant energy source. To address this challenge, a multi-stable, broadband and tri-hybrid energy harvesting technique was recently proposed, which can work well under low-frequency, low-amplitude, and time-varying ambient sources. In this work, we will introduce our idea, following the recently proposed energy harvester and the dynamic responses of a train vehicle, to design a self-sustained sensing system on trains. Supported by this self-powered system, accelerometers and microphones deployed on an in-service train (in axle boxes/bogie frames) can measure vibration and noise data directly. The correlation of the vibration and noise data can then be analyzed simultaneously to identify the dynamic behavior (e.g., wheel defects) of a moving train.


Author(s):  
Wei Guo ◽  
Yang Wang ◽  
Hanyun Liu ◽  
Yan Long ◽  
Lizhong Jiang ◽  
...  

The main goal of this paper is to perform the safety assessment of high-speed trains (HSTs) on the simply supported bridges (SSBs) under low-level earthquakes, which are frequently encountered by HSTs, utilizing spectral intensity (SI) index. First, the HST’s limit displacements, which are calculated by using the multi-body train model with detailed wheel–rail relationship, varying with train speed, frequency and amplitude of a sinusoidal base excitation are obtained. Then, based on the obtained HST’s limit displacements, the spectral intensity limits (SIL) graded by the train’s running speed are calculated, and the relationship between the bridge seismic dynamic responses and the train’s running safety was established. Next, the method that utilizes the SI and the SIL indexes to evaluate the HST’s running safety was proposed and verified by comparing with the evaluation result of the train–track–bridge interaction model. Based on the proposed SI index, the HST’s running safety on the SSBs was evaluated under earthquakes, considering different pier heights and site types. The results showed that the low-frequency components of the ground motions are unfavorable to the HST’s running safety, and the height of bridge piers has a significant impact on running safety.


2013 ◽  
Vol 13 (03) ◽  
pp. 1250064 ◽  
Author(s):  
CHAOYI XIA ◽  
HE XIA ◽  
NAN ZHANG ◽  
WEIWEI GUO

A dynamic analysis model is established for a coupled high-speed train and bridge system subjected to collision loads. A 5 × 32 m continuous high-speed railway bridge with PC box girders is considered in the illustrative case study. Entire histories of a CRH2 high-speed EMU train running on the bridge are simulated when the truck collision load acts on the bridge pier, from which the dynamic responses such as displacements and accelerations of the bridge, and the running safety indices such as derailment factors, offload factors and lateral wheel/rail forces of the train are computed. For the case study, the running safety indices of the train at different speeds on the bridge when its pier is subjected to a truck collision with different intensities are compared with the corresponding allowances of the Chinese Codes. The results show that the dynamic response of the bridge subjected to truck collision loads is much greater than the one without collision, which can drastically influence the running safety of high-speed trains.


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