Dynamic responses of multilayered poroelastic ground under moving train loads considering effects of track irregularity

2021 ◽  
pp. 100660
Author(s):  
Ziheng Gan ◽  
Jiangu Qian ◽  
Zhi Lyu
Keyword(s):  
Dynamic Responses ◽  
Track Irregularity ◽  
Moving Train

Comparison on General Track Spectrum for Chinese Main Railway Lines and Track Spectrum of American Railway Lines

2011 ◽  
Vol 250-253 ◽  
pp. 3822-3826 ◽  
Author(s):  
Xian Mai Chen ◽  
Xia Xin Tao ◽  
Gao Hang Cui ◽  
Fu Tong Wang
Keyword(s):  
Dynamic Performance ◽  
Dynamic Responses ◽  
Wave Band ◽  
Wheel Load ◽  
Railway Line ◽  
Acceleration Rate ◽  
Time Histories ◽  
Railway System ◽  
Dynamic Performances ◽  
Track Irregularity

The general track spectrum of Chinese main railway lines (ChinaRLS) and the track spectrum of American railway lines (AmericaRLS) are compared in terms of character of frequency domain, statistical property of time domain samples and dynamic performance. That the wavelength range of the ChinaRLS, which is characterized by the three levels according to the class of railway line, is less than AmericaRLS at common wave band of 1~50m is calculated. Simultaneously, the mean square values of two kinds of track spectra are provided at the detrimental wave bands of 5~10m, 10~20m, and so on. The time-histories of ChinaRLS and AmericaRLS are simulated according to the trigonometric method, and the digital statistical nature of simulated time samples is analyzed. With inputting the two kinds of time-histories into the vehicle-railway system, the comparative analysis of the two kinds of dynamic performances for ChinaRLS and AmericaRLS is done in terms of car body acceleration, rate of wheel load reduction, wheel/rail force, and the dynamic responses of track structure. The result shows that ChinaRLS can characterize the feature of the Chinese track irregularity better than AmericaRLS, the track irregularity with the ChinaRLS of 200km/h is superior to the AmericaRLS, and the track irregularity with the ChinaRLS of 160km/h corresponds to with the sixth of AmericaRLS.

Estimation of Track Irregularity Based on Genetic Algorithm and Unscented Kalman Filtering

2012 ◽  
Author(s):  
Hongmei Shi ◽  
Zujun Yu
Keyword(s):  
Genetic Algorithm ◽  
Kalman Filtering ◽  
High Speed ◽  
Measurement Data ◽  
Estimation Method ◽  
Coupling Model ◽  
Dynamic Responses ◽  
The Real ◽  
True Value ◽  
Track Irregularity

Track irregularity is the main excitation source of wheel-track interaction. Due to the difference of speed, axle load and suspension parameters between track inspection train and the operating trains, the data acquired from the inspection car cannot completely reflect the real status of track irregularity when the operating trains go through the rail. In this paper, an estimation method of track irregularity is proposed using genetic algorithm and Unscented Kalman Filtering. Firstly, a vehicle-track vertical coupling model is established, in which the high-speed vehicle is assumed as a rigid body with two layers of spring and damping system and the track is viewed as an elastic system with three layers. Then, the static track irregularity is estimated by genetic algorithm using the vibration data of vehicle and dynamic track irregularity which are acquired from the inspection car. And the dynamic responses of vehicle and track can be solved if the static track irregularity is known. So combining with vehicle track coupling model of different operating train, the potential dynamic track irregularity is solved by simulation, which the operating train could goes through. To get a better estimation result, Unscented Kalman Filtering (UKF) algorithm is employed to optimize the dynamic responses of rail using measurement data of vehicle vibration. The simulation results show that the estimated static track irregularity and the vibration responses of vehicle track system can go well with the true value. It can be realized to estimate the real rail status when different trains go through the rail by this method.

Fatigue Damage Analysis of Monolithic Joint of Steel Truss Bridge Considering Welding Residual Stresses

2011 ◽  
Vol 71-78 ◽  
pp. 3123-3126 ◽  
Author(s):  
Wen Li Wang ◽  
Jie He ◽  
Mang Mang Zhang
Keyword(s):  
Residual Stresses ◽  
Hot Spots ◽  
Low Cycle Fatigue ◽  
Welding Residual Stress ◽  
Dynamic Responses ◽  
Steel Truss Bridge ◽  
Fatigue Damage Analysis ◽  
History Of ◽  
Truss Bridge ◽  
Moving Train

This investigation firstly performs a thermal elasto-plastic analysis using finite element techniques to evaluate residual stresses in monolithic joint weldments, then develops an effective procedure by combining the welding residual stress and dynamic responses by moving train loads , finally calculates the stress history of hot spots in local weldments .The results showed that the stresses of some hot spots in weldments had exceeded the yield stress of steel , so the fatigue of these spots should be categorized into low cycle fatigue; the load application on the welded bridge produces a reassessment of the stress field in the weldments and, in particular, a relaxation of the maximum stress.

Influences of Subgrade Structure Form on Dynamic Responses of Railway Subgrade under Cyclic Loading

2016 ◽  
Vol 851 ◽  
pp. 757-762
Author(s):  
Jun Hua Xiao
Keyword(s):  
Plastic Deformation ◽  
Cyclic Loading ◽  
Maximum Stress ◽  
Dynamic Stress ◽  
Dynamic Stiffness ◽  
Field Tests ◽  
Dynamic Responses ◽  
Structure Form ◽  
The One ◽  
Moving Train

This paper presents conducted field tests of cyclic loading for railway subgrade. These tests studied the influences of subgrade structure forms of embankment and cutting on the dynamic responses of railway subgrade. The considered dynamic responses included the distribution of dynamic stress in railway subgrade, and the elastic deformation, dynamic stiffness, and cumulative plastic deformation on subgrade surface. The number of cyclic loading in testing was separately about two millions for an embankment and a cutting. The dynamic deviator stress applied on subgrade surface was 92kPa to simulate the maximum stress induced by moving train for the designed railway. Gathered data showed that the dynamic stiffness on subgrade surface for a cutting was approximately a half of the one for an embankment. However, the cumulative plastic deformation was essentially the same for the two forms of subgrade (i.e. the embankment and the cutting). These results provide references for the design of railway subgrade.

An advanced vehicle–slab track interaction model considering rail random irregularities

2017 ◽  
Vol 24 (19) ◽  
pp. 4592-4603 ◽  
Author(s):  
Lei Xu ◽  
Zhaowei Chen ◽  
Wanming Zhai
Keyword(s):  
Dynamic Model ◽  
Calculation Method ◽  
Three Dimensional ◽  
Interaction Model ◽  
Dynamic Responses ◽  
Computational Time ◽  
Infinite Length ◽  
Slab Track ◽  
Rail Irregularity ◽  
Track Irregularity

This paper investigates a more advanced vertical vehicle–slab track interaction model (VTIM) by considering the discontinuity of track slabs, besides, it can be degenerated to the traditional two-dimensional model conveniently. Moreover, a cyclic calculation method (CCM) is further developed to solve infinite length calculations. On this basis, the proposed dynamic model and CCM are validated by comparing with the more comprehensive three-dimensional train–track model and fixed-point excitation method. Then, from aspects of probability statistics and frequency analysis, an illustrative example is particularly conducted to comprehensively characterize the dynamic responses of vehicle–slab track systems, in which the representative and realistic rail irregularity sets simulated by the track irregularity probabilistic model are used as the loading inputs. Results show that, with a low consumption of computational time and computer memory, the dynamic results derived from VTIM and CCM have a high accuracy, which indicates that the proposed dynamic model and calculation method can be efficiently and accurately used to analyze train–slab track interactions.

Effect of Track Geometric Irregularity on Dynamic Characteristics of Gear Transmission in a Locomotive

2017 ◽  
Author(s):  
Tao Zhang ◽  
Zaigang Chen ◽  
Jie Zhang ◽  
Shunqi Sui ◽  
Cheng Pan
Keyword(s):  
Dynamic Characteristics ◽  
Life Prediction ◽  
Dynamic Performance ◽  
Gear Transmission ◽  
Fatigue Life Prediction ◽  
Dynamic Responses ◽  
Mean Square ◽  
Track Irregularity ◽  
Working Performance ◽  
Statistical Indicators

Gear transmission is a key component in locomotive where it delivers the traction or braking forces between the motor and the wheelset. Its working performance has a direct effect on the operating reliability and safety. Therefore, investigation on the dynamic characteristics of the gear transmission in locomotives is very meaningful. In this study, a gear transmission-locomotive-track spatial coupled dynamic model is established based on the classical locomotive-track coupled dynamics and the gear dynamics theory. Based on this model, the dynamic responses of the gear transmission can be analysed under excitations from different track geometrical irregularity, and the dynamic performance of the gear transmission can be obtained. This paper also studies the effect law of the track irregularity on the vibration of the gear transmission by using statistical indicators RMS (Root Mean Square) and PtP (Peak-to-Peak). The results indicate that the track geometrical irregularity has an obvious impact to the dynamic performance of gear transmission. The dynamic response of the gear transmission will increase violently when the locomotive runs on the track in a worse condition. The results are expected to be capable of providing some references for fatigue life prediction and reliability analysis of the gear transmissions in locomotive.

A Versatile 3D Vehicle-Track-Bridge Element for Dynamic Analysis of the Railway Bridges under Moving Train Loads

2019 ◽  
Vol 19 (04) ◽  
pp. 1950050 ◽  
Author(s):  
Xiang Xiao ◽  
Wei-Xin Ren
Keyword(s):  
Virtual Work ◽  
Interaction Analysis ◽  
Equations Of Motion ◽  
Time Integration ◽  
Contact Forces ◽  
Dynamic Responses ◽  
Railway Bridges ◽  
Beam Elements ◽  
Track Bridge ◽  
Moving Train

There has been a growing interest to carry out the vehicle–track–bridge (VTB) dynamic interaction analysis using 2D or 3D finite elements based on simplified wheel–rail relationships. The simplified or elastic wheel–rail contact relationships, however, cannot consider the lateral contact forces and geometric shapes of the wheel and rails, and even the occasional jump of wheels from the rails. This does not guarantee a reliable analysis for the safety running of trains over bridges. To consider the wheel–rail constraint and contact forces, this paper proposes a versatile 3D VTB element, consisting of a vehicle, eight rail beam elements, four bridge beam elements, and continuous springs as well as the dampers between the rail and bridge girder. With the 3D VTB element matrices formulated, a procedure for assembling the interaction matrices of the 3D VTB element is presented based on the virtual work principle. The global equations of motion of the VTB interaction system are established accordingly, which can be solved by time integration methods to obtain the dynamic responses of the vehicle, track and bridge, as well as the stability and safety indices of the moving train. Finally, an illustrative example is used to verify the proposed the versatile 3D VTB element for the dynamic interactive analysis of railway bridges under moving train loads.

scholarly journals Dynamic Responses of Interspersed Railway Tracks to Moving Train Loads

2018 ◽  
Vol 18 (01) ◽  
pp. 1850011 ◽  
Author(s):  
Sakdirat Kaewunruen ◽  
Tomasz Lewandrowski ◽  
Kritditorn Chamniprasart
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Dynamic Responses ◽  
Railway Tracks ◽  
Finite Element Package ◽  
Negative Effect ◽  
Dynamic Amplification ◽  
Term Performance ◽  
Moving Train ◽  
Dynamic Phenomena

This paper investigates novel dynamic phenomena of interspersed railway tracks. The interspersed method is commonly carried out by spot-replacing old timber sleepers with new concrete sleepers. Although this interspersed approach provides a short-term solution, such method has a negative effect on the long-term performance of railway tracks. It is evident that the performance of interspersed tracks can quickly deteriorate after some years. As a result, this paper is the first to evaluate dynamic responses of the interspersed track caused by a moving train load in order to understand the root cause of swift track deterioration. Interspersed track models in three-dimensional space have been developed using a finite element package, STRAND7. The model was validated earlier with experimental results. Parametric studies have been conducted to evaluate dynamic responses of the interspersed railway tracks, including dynamic displacement, frontal uplift, rear uplift and accelerations of rail over sleeper, rail at midspan, sleeper at rail seat, and sleeper at midspan. Dynamic amplification phenomena are highlighted as they convey a new insight into dynamic phenomena identifying the real source of track deterioration.

Sign in / Sign up

Export Citation Format

Share Document