scholarly journals The vehicle impact on the corrugated steel shell in soil-steel structures

2017 ◽  
Vol 2017 (9) ◽  
pp. 18-29
Author(s):  
Czesław Machelski
Keyword(s):  
High Speed ◽  
Steel Structures ◽  
Travel Speed ◽  
Dynamic Loads ◽  
Rolling Stock ◽  
Steel Shell ◽  
Vehicle Speed ◽  
Rail Vehicles ◽  
Vehicle Impact ◽  
The Impact

The paper presents the results of soil-steel structures tests under road and rail vehicles loads, which change their position alongthe track. Quasi static loads are considered in both stepping and continuous measurement method (with minimum travel speed). The impact of dynamic loads from vehicles as a function of vehicle speed was analyzed. Heavy, low-speed driving rides and as a separate group the passage of passenger trains in high speed journeys were con-si-dered. In this cases numerical simulations are performed using com-plex models of soil-steel structures. The specificity (difference) of dynamic effects from dynamic loads of rolling stock on soil-steel structures in relation to classic steel bridges is specified in the paper. The present-ed results from tests shows the favorable interaction of the railway tracks and substructures with the corrugated steel shell in the backfi lling as in the railway embankments.

Analysis on Impact Loading at Rail Welds at High Speed

2008 ◽  
Author(s):  
Guangwen Xiao ◽  
Xinbiao Xiao ◽  
Zefeng Wen ◽  
Xuesong Jin
Keyword(s):  
Impact Loading ◽  
High Speed ◽  
Hertzian Contact ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Explicit Integration ◽  
Normal Forces ◽  
Rail Irregularity ◽  
Multi Body ◽  
The Impact

When a railway vehicle passes through a track with different weld irregularities at high speed, the impact loading of the vehicle coupled with the track is investigated in detail using a coupled vehicle/track model. In this model, a half vehicle is considered and modeled as a multi-body system. In the track model, a Timoshenko beam resting on discrete sleepers is applied to model each rail. Each sleeper is modeled as a rigid body accounting for its vertical, lateral, roll motions. A moving sleeper support model is used to simulate the interaction of the vehicle and the track. The ballast bed is replaced with equivalent masses. The equivalent dampers and springs are used to replace the connections between the parts of the vehicle and track. In calculating the coupled vehicle and track dynamics, Hertzian contact theory and the creep force theory by Shen et al. are, respectively, used to calculate the normal forces and the creep forces between the wheels and the rails. The motion equations of the vehicle-track are solved by means of an explicit integration method. The weld rail irregularity is modeled by setting a local track vertical deviation at a rail weld joint, which is described with a simplified cosine function. In the numerical analysis the effect of the different wavelength, depth, the position of the welded joint in a sleeper span, and vehicle speed is taken into account. The numerical results obtained are greatly useful in the tolerance design of welded rail profile irregularity caused by damage and hand-grinding after rail welding.

scholarly journals The Impact of Rolling Stock Heterogeneity on Tram Stop Dwell Time

2021 ◽  
Vol 12 (1) ◽  
pp. 84
Author(s):  
Igor Majstorović ◽  
Maja Ahac ◽  
Saša Ahac ◽  
Silvio Bašić
Keyword(s):  
Dwell Time ◽  
Travel Speed ◽  
Influential Factors ◽  
Rolling Stock ◽  
Closing Time ◽  
Door Opening ◽  
Design Characteristics ◽  
Definition Of ◽  
The Impact ◽  
The City

The prediction of stop dwell time is a major issue in travel speed modeling, i.e., in the definition of travel time for high-frequency and high-ridership rail public transport. This is due to the numerous influential factors associated with stop dwell time, variable both in space and time, such as passenger flow, vehicle and stop design characteristics, and traffic organization. To investigate the impact of the heterogeneity of tram vehicles on stop dwell time, a survey was conducted regarding the tram network of the City of Zagreb. The dwell time at three consecutive island stops served by three different tram vehicle types was analyzed. The stops are located near the city center, in a separate tram corridor, at the far side of signalized intersections. Dwell time was determined and evaluated through the statistical analysis of observed, measured, and video-recorded data. The results show that at stops with up to 200 passengers per hour, the dwell time is around 15 s. For volumes of 20 passengers or less per tram, the dwell time is mostly affected by the tram door opening mechanism and opening/closing time. As the passenger volumes become higher, the number of doors per vehicle becomes more significant.

scholarly journals Flexible-Rigid Wheelset Introduced Dynamic Effects due to Wheel Tread Flat

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Awel Momhur ◽  
Y. X. Zhao ◽  
Liwen Quan ◽  
Sun Yazhou ◽  
Xialong Zou
Keyword(s):  
High Speed ◽  
Statistical Approach ◽  
Impact Load ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Dynamic Impact ◽  
Element Analysis ◽  
Wheel Flat ◽  
Wheel Radius ◽  
The Impact

The widespread faults that occur in railway wheels and can cause a massive dynamic impact are the wheel tread flat. The current work considered changes in vehicle speed or wheel radius deviation and studied the dynamic impact load. The modal technique for the impact evaluation induced by the wheel flat was proposed via the finite element analysis (FEA) software package ANSYS, integrated into a multibody dynamics model of the high-speed train CRH2A (EMU) through SIMPACK. The irregularity track line has developed and depends on the selected simulation data points. Additionally, a statistical approach is designed to analyze the dynamic impact load response and effect and consider different wheel flat lengths and vehicle speeds. The train speed influence on the flat size of the vertical wheel-rail impact response and the statistical approach are discussed based on flexible, rigid wheelsets. The results show that the rigid wheel flat has the highest vertical wheel impact load and is more significant than the flexible wheel flat force. The consequences suggest that the wheelset flexibility can significantly improve vertical acceleration comparably to the rigid wheel flats. In addition, the rendering of the statistical approach shows that the hazard rate, PDF, and CDF influence increase when the flat wheel length increases.

Impact on the track from EMU commuter train

2018 ◽  
Vol 77 (4) ◽  
pp. 191-199
Author(s):  
A. M. Brzhezovskiy
Keyword(s):  
Statistical Processing ◽  
Travel Speed ◽  
Outer Edge ◽  
Rolling Stock ◽  
Design Stage ◽  
Customs Union ◽  
Technical Parameters ◽  
Test Loop ◽  
Impact Indicators ◽  
The Impact

The largest part of operating fleet of EMU trains, operated on the railways of the JSC “Russian Railways”, belongs to the category “ЭП” - electric commuter trains for transporting passengers in suburban areas with a length of the turnover section not exceeding 200 km with a speed of up to 120 km/h. The category of “ЭП” electric trains is fully formed by the domestic rolling stock produced since 1993. After putting Safety Norms NB ZhT 03-98 into force in 1998 and subsequently entering Technical Regulations of the Customs Union - TR TS 001/2011 virtually all new or upgraded series of EMU trains of the category «ЭП» within the acceptance and certification tests were experimentally investigated by the Test Loop of the JSC “VNIIZhT” (ITs ZhT) for compliance with safety requirements from the conditions for ensuring normative level of indicators of interaction between rolling stock and the track. Main technical parameters were shown as well as design features of carriage part of EMU trains of the category “ЭП”. The following features were considered: comparative quantitative values and dependencies on the travel speed and the level of unbalanced accelerations of the experimental indicators of influence on the track of EMU train cars of the category “ЭП”, determined from the results of statistical processing of realizations of dynamic stresses in the throttle of rail sole and lateral forces; vertical and lateral (horizontal) forces transmitted from the wheels to the rail head; stability coefficients of assembled rails and sleepers from the transverse shift along the ballast, as well as the coefficients f of the transition from the axial stresses in the base of the rail to the stresses in the outer edge of the rail sole. The quantitative values of the impact indicators on the track of EMU train cars of the category “ЭП” with a design speed of 120 km/h, obtained from the results of complex certification and acceptance tests, are in the range of values regulated by the current regulatory documents. It is recommended to use the values of the impact indicators on the track to evaluate the design of the carriage part of EMU train cars at the design stage.

scholarly journals Investigation of the psychophysiological response of passengers of fast trains with the different comfort level

2021 ◽  
Vol 100 (4) ◽  
pp. 318-326
Author(s):  
Evgeniy Yu. Bersenev ◽  
Vladimir I. Dubinin ◽  
Vyacheslav M. Ermakov ◽  
Anna I. Kirpicheva
Keyword(s):  
High Speed ◽  
The Body ◽  
Comfort Level ◽  
Movement Speed ◽  
Rolling Stock ◽  
Technical Data ◽  
Normative Documents ◽  
Staff Members ◽  
High Speed Trains ◽  
The Impact

Introduction. To create a regulatory framework, including harmonized with European normative documents in terms of assessing passengers’ comfort, the standard of the enterprise STO RZD “Services in railway transport was developed. Rules for assessing the level of comfort of passengers on trains.” The objective of the study is to compare the indices of the comfort level of passengers, determined by the values of the accelerations acting on them, with the psychological sensations and physiological changes in the body arising in this case, depending on the rolling stock and the state of the track. Material and methods. The experiment using ECG monitoring devices was carried out in four groups of eleven people, six men and five women aged 30-55 years. Additionally, in each group, a psychological survey of 11 more passengers was carried out. All of them were staff members of the Russian Railways divisions. Results. When traveling on high-speed trains “Lastochka” and “Sapsan,” the respondents more often note drowsiness and an exhausted state’s progression. At the end of the trip, they often emphasize stiffness, discomfort, numbness, and numbness of the leg muscles, probably associated with an extended stay in a forced position in the absence of specific freedom movements. In the “lying” position, a person experiences less fatigue, which, according to the sensations, hardly differs from the conditions of a trip in a “sitting” position during short journeys. Regulatory changes in the cardiovascular system are manifested with the combined influence of uncanceled accelerations (the impact of centrifugal forces) and movement speed changes. Conclusion. Carrying out a questionnaire survey and physiological measurements of the dynamics of heart rate fluctuations on the investigated sections of the routes in combination with the obtained technical data on the nature of mobile rail vehicles’ movement confirm the absence of critical discomfort for passengers when traveling on passenger and high-speed trains. The calculated values of the average and constant comfort levels are consistent and do not require correction of the corresponding scales’ values.

scholarly journals Investigation of the some problems of running safety of rolling stock on the Ukrainian railways

2016 ◽  
Vol 40 (4) ◽  
pp. 15-27 ◽  
Author(s):  
Rostyslav Domin ◽  
Iurii Domin ◽  
Ganna Cherniak ◽  
Anatolii Mostovych ◽  
Valeria Konstantidi ◽  
...  
Keyword(s):  
High Speed ◽  
Simulation Analysis ◽  
Technical Condition ◽  
Rolling Stock ◽  
Railway Vehicles ◽  
Running Safety ◽  
Time Period ◽  
Software And Hardware ◽  
The Impact ◽  
Non Destructive

The results of the evaluation of the running safety conditions of railway vehicles are presented by means of computer simulation. Analysis of the possible reasons for derailment by means of performance evaluation of rolling stock and track interaction are presented. The impact of the technical condition of the dampers on the running safety of passenger wagons is considered. The localization of possible damages of bearing structures of high-speed train is determined with the help of calculation of the strength characteristics and the method of non-destructive metallography. There is the information about the development of software and hardware complexes providing an instrumental assessment of the technical condition of railway vehicles. Portable device is proposed for measuring the static load of the wheels of the rolling stock units on the track. The work on creation of stationary devices for automatic wheels fault detection in order to reduce the time period from the appearance of the defect was conducted. The brainchild of the mobile system of controlling running tests and dynamic diagnostics of rolling stock was considered.

scholarly journals Numerical analysis of beam rail bridges - impact factors in the vertical deflection

2017 ◽  
Vol 2017 (9) ◽  
pp. 11-17 ◽  
Author(s):  
Monika Podwórna
Keyword(s):  
High Speed ◽  
Equations Of Motion ◽  
Impact Factors ◽  
Vertical Deflection ◽  
Lagrange Equations ◽  
High Speeds ◽  
Rail Vehicles ◽  
Non Linear ◽  
Random Track Irregularities ◽  
The Impact

The impact factors in the vertical deflection obtained in dynamic analysis of BTT systems - bridged / track structure / high speed train (BTT) - are discussed. The BTT system is one of 5 bridges spanning from 15 m to 27 m, modelled as simply supported beams loaded by ICE-3 trains traveling at high speeds. The two-dimensional, physically non-linear BTT model includes: viscoelastic suspension of rail vehicles on two independent axle bogies and non-linear one-sided wheel-rail contact springs according to Hertz theory, access zones for composite construction. The BTT system was divided into subsystems loaded with vertical interactions transmitted by elastic or viscoelastic and physically linear or nonlinear constraints. Using Lagrange equations and internal aggregation of subsystems, discretised according to the finite element method, matrix equations of motion of the subsystems were obtained, with explicit linear left sides and nonlinear implicit right sides, which were integrated numerically using the Newmark method with parameters βN=1/4, γN=1/2. The analysis focus on the effect of random track irregularities on the dynamic response of BTT systems.

scholarly journals ДОСЛІДЖЕННЯ ВПЛИВУ ЗМІЩЕННЯ ПАКУВАННЯ ВЗДОВЖ ОСІ БОБІНОТРИМАЧА НА КРИТИЧНІ ШВИДКОСТІ

2020 ◽  
Vol 144 (2) ◽  
pp. 13-23
Author(s):  
Б. С. Завертанний ◽  
О. П. Манойленко ◽  
О. О. Акимов
Keyword(s):  
High Speed ◽  
Center Of Mass ◽  
Axial Direction ◽  
Dynamic Loads ◽  
Practical Significance ◽  
Stable Operation ◽  
Direct Drive ◽  
Critical Speeds ◽  
The Impact

Creation of a mathematical model of the mechanism of winding of rewinding machines, research of influence of size of shift of packing on critical speeds and development of recommendations for the decision of the set task. Method. When working out the thread for packaging, high-speed winding mechanisms are subject to high requirements, both for the quality of the resulting packaging and for the speed of the bobbin holder. When installing the spool on the spool holder, it is possible to shift it in the axial direction from the design position, which leads to a change in the position of the center of mass of the package with the spool, and in accordance with changes in dynamic loads on the spool holder. Therefore, there is a need to determine the magnitude of the impact of the displacement of the package along the axis of the bobbin holder on the operating speeds of the equipment and the quality of the resulting packages. In the winding process, the placement of the package on the bobbin holder of the winding mechanism of the rewinding machine plays an important role. The displacement of the center of mass of the package affects both the operating speed of the equipment and the quality of the package. In rewinding machines, a mechanism for controlling the thickness of the package is installed, which controls the speed processes during winding. When the coil is shifted towards the top of the cone, incomplete packing (less weight) is developed. When shifted to the side opposite the top of the packing cone, on the contrary, the weight of the packing increases. In addition, the magnitude of the displacement of the package affects the dynamic loads of the winding mechanism. Results. The influence of the magnitude of the packing displacement along the axis of the bobbin holder on the critical speeds of the winding mechanism and the quality of packing is determined. Scientific novelty. The study and analysis of the influence of the magnitude of the displacement of the bobbin with packaging on the critical speeds of the winding mechanism are conducted. The magnitude of the influence of the position of the masses of the center of the coil with packing relative to the bobbin holder on the value of the critical speeds of the winding mechanism is determined. The obtained results allow to control the range of working speeds of the winding mechanism depending on the parameters of the position of the spool on the spool holder, which can be used to adjust the speed of the winding process when packing the spool and make changes when designing the rewinding equipment. The method of determining the maximum possible speeds in the process of rewinding textile material on rewinding machines with direct drive of the bobbin, taking into account the position of the bobbin on the bobbin holder, which can be used in the design of new mechanisms or modernization of existing ones. Practical significance. A dynamic model of the winding mechanism has been developed. The magnitude of the influence of packing displacement on critical speeds is shown. Methods and designs for improving the quality of packaging and stable operation of equipment are proposed.

scholarly journals Study on the Urban Rail Transit Sleeper Spacing Considering Vehicle System

2019 ◽  
Vol 296 ◽  
pp. 01008
Author(s):  
Yu Zou ◽  
Yongpeng Wen ◽  
Qian Sun
Keyword(s):  
High Speed ◽  
Coupling Model ◽  
Vertical Vibration ◽  
Vibration Response ◽  
Urban Rail Transit ◽  
Vehicle Speed ◽  
Vertical Coupling ◽  
Vehicle System ◽  
Spectrum Density ◽  
The Impact

To design the optimal sleeper spacing of the track and reduce the vertical vibration of the rail, the influence of the sleeper spacing on the rail vibration is analysed in the vehicle-track vertical coupling model. By comparing the effects of vehicle speed and load on the vibration response of rails under different sleeper spacings, the importance of vehicle system is pointed out. According to the power spectrum density of the vertical rail displacement, the optimal sleeper spacing under the specific line is proposed, and verified via the vibration decay rate. The results show that the sleeper spacing directly affects the first-order Pinned-pinned vibration of the rail, and the effects of the speed and the load on the vibration response are different. In the low-speed section, the impact of the sleeper spacing on the vibration response is smaller, and the larger spacing can be appropriately selected to reduce the number of sleeper to save costs. However, in the high-speed section, the impact is larger, and the speed and the load should be comprehensively considered to select the optimal sleeper spacing.

scholarly journals Wheel-rail impact interaction on the high-speed railroad bridges

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Vladimir Poliakov ◽  
Dang Ngoc Thanh
Keyword(s):  
Computer Simulation ◽  
Contact Force ◽  
High Speed ◽  
Rolling Stock ◽  
Adequate Model ◽  
Impact Interaction ◽  
Bridge Superstructure ◽  
Railroad Bridge ◽  
The Impact ◽  
High Speed Railroad

The paper describes interaction of high-speed rolling stock and railroad bridge deck and proves the importance of adequate model of wheel (mechanism) and rail (structure) interaction. The model must consist of a rail and slabs of the ballastless deck. The paper characterizes the results of computer simulation of perspective rolling stock passing through high speed railroad bridge, that contains the uniform bridge superstructure for Moscow – Kazan line. The paper shows that in case of resonant bridge superstructure vibration the risk of derailment is high because of the decline of the wheel-rail contact force down to zero, which means wheel uplift. Moreover, the impact of the wheel is the result of uplift and the impact value is similar to the impact from impossible damages of wheels or rail on high speed railroad in consequence of which rail breaking occur. This rail breaking is the most frequent reason of derailment. The impact forces are equivalent to the impact of the fresh flat of the wheel and may be more than 300 kN while static force is equal to 85 kN. The vertical contact force is rising from zero to maximum value for 0.002 to 0.004 s after uplift. The computer simulation results show that it is the bridge superstructure resonance, which leads to impact interaction. The rail fasteners rigidity decline causes vertical interaction force decrease during the impact but the derailment risk still exists during vibration of “bridge – track – train” system.

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