scholarly journals Vertical vibrations of composite bridge/track structure/high-speed train systems. Part 3: Deterministic and random vibrations of exemplary system

2014 ◽  
Vol 62 (2) ◽  
pp. 305-320 ◽  
Author(s):  
M. Podworna ◽  
M. Klasztorny
Keyword(s):  
High Speed ◽  
Extreme Values ◽  
Track Structure ◽  
Vertical Acceleration ◽  
Computer Algorithms ◽  
High Speed Train ◽  
Random Factor ◽  
Static And Dynamic Analysis ◽  
Time Histories ◽  
Vertical Vibrations

Abstract Based on the one-dimensional quasi-exact physical and mathematical modelling of a composite (steel-concrete) bridge/track structure/high-speed train system (BTT), developed in Part 2, advanced computer algorithms for the BTT numerical modelling and simulation as well as a computer programme to simulate vertical vibrations of BTT systems are developed. The exemplary bridge under numerical quasi-static and dynamic analysis, designed according to Polish standards, has a 15.00 m span length and belongs to the SCB series-of-types developed in Part 1. The bridge is loaded by a German ICE-3 high-speed train moving at the resonant and maximum operating speeds. A continuously welded ballasted track structure adapted to high operating velocities is applied. The output quantities include: time-histories of the vertical deflection of the main beams at the midspan, time-histories of the longitudinal normal stress in the bottom fibres of the main beams at the midspan, time-histories of the vertical acceleration of the bridge deck at the midspan, time-histories of the vertical accelerations of the suspension pivots in car-bodies, time-histories of the dynamic pressures of the wheel sets of moving rail-vehicles. The design quantities, understood as the extreme values of the output quantities, are used to verify the design conditions. The basic random factor, i.e. vertical track irregularities of the track, is taken into consideration. Basic statistics of the design quantities treated as random variables are calculated and taken into account in the design conditions.

Vertical vibrations of composite bridge/track structure/high-speed train systems. Part 1: Series-of-types of steel-concrete bridges

2014 ◽  
Vol 62 (1) ◽  
pp. 165-179 ◽  
Author(s):  
M. Podworna ◽  
M. Klasztorny
Keyword(s):  
High Speed ◽  
Concrete Bridges ◽  
Track Structure ◽  
High Speed Train ◽  
Limit States ◽  
Material Optimization ◽  
Ballasted Track ◽  
Composite Bridge ◽  
Vertical Vibrations ◽  
Structural Solutions

Abstract A new series-of-types of single-span simply-supported railway composite (steel-concrete) bridges, with a symmetric platform, has been designed according to the Polish bridge standards. The designed bridges/viaducts are located on the main railways of the classification coefficient k = +2. A ballasted track structure adapted to high operating speeds has also been designed. The ultimate limit states and the limit states corresponding to the bridges undertaken are collected and discussed. The bridges have been designed in accordance with contemporary art engineering, with geometric and material optimization, avoiding overdesign. A new methodology of numerical modelling and simulation of dynamic processes in composite bridge/ballasted track structure/high speed train systems, developed in Part 2 and Part 3, has been applied and implemented in a problem-oriented computer programme. A new approach to predicting forced resonances in those systems is formulated and tested numerically. It has been proved that in the case of typical structural solutions of bridges and ballasted track structures, it is necessary to introduce certain limitations for operating speeds of trains

scholarly journals Effect of random track irregularities on selected composite bridge / track structure / high-speed train system vibrations

2013 ◽  
Vol 12 (1) ◽  
pp. 259-266
Author(s):  
Monika Podworna ◽  
Marian Klasztorny
Keyword(s):  
High Speed ◽  
Contact Stiffness ◽  
Track Structure ◽  
Computer Algorithms ◽  
High Speed Train ◽  
Approach Slabs ◽  
Composite Bridge ◽  
Random Track Irregularities ◽  
Train System ◽  
Track Irregularities

A theory of the quasi-exact physical and mathematical modelling of the composite (steel–concrete) bridge / ballasted track structure / high-speed train system (BTT) was developed, including viscoelastic suspensions of rail-vehicles on two-axle bogies, the non-linear Hertz contact stiffness and one-sided contact between the wheel sets and the rails, the viscoelastic and inertia features of the bridge, the viscoelastic track structure on and beyond the bridge, the approach slabs, and random track irregularities. Based on this theory, advanced computer algorithms for the BTT numerical modelling were written and a computer program to simulate the vertical vibrations of the BTT systems was developed. The bridge subject to the preliminary dynamic analysis and designed according to Polish standards has a 15.00 m span length. The bridge was loaded by the German ICE-3 high-speed train moving at the critical (180 and 270 km/h) and the maximum (300 km/h) operating speeds.

scholarly journals The coupled effects of bending and torsional flexural modes of a high-speed train car body on its vertical ride quality

2019 ◽  
Vol 233 (4) ◽  
pp. 979-993 ◽  
Author(s):  
Vahid Bokaeian ◽  
Mohammad A Rezvani ◽  
Robert Arcos
Keyword(s):  
Analytical Model ◽  
Quality Index ◽  
High Speed ◽  
Ride Quality ◽  
Vertical Acceleration ◽  
Beam Model ◽  
High Speed Train ◽  
Flexural Mode ◽  
Car Body ◽  
Rail Irregularities

This study is focused on the effects of bending and torsional flexural modes of the car body on the ride quality index of a high-speed train vehicle. The Euler–Bernoulli beam model is used to extract an analytical model for a high-speed train vehicle car body in order to investigate its bending and torsional flexural vibrations. The rigid model includes a car body, two bogie frames, and four wheelsets such that, each mass has three degrees of freedom including vertical displacement, pitch motion, and roll motion. The results obtained with the proposed analytical model are compared with experimental measurements of the car body response of a Shinkansen high-speed train. Moreover, it is determined that the bending and torsional flexural modes have significant effects on the vertical acceleration of the car body, particularly in the 9–15 Hz frequency range. Furthermore, the ride quality index is calculated according to the EN 12299 standard and it is shown that the faster the train the more affected is the ride quality by the flexural modes. In addition, the effect of coherence between two rail irregularities (the right and the left rails) on the results of the simulation is investigated. The results conclude that if the irregularities are completely correlated the torsional flexural mode of the car body does not appear in the response. Also, the first bending flexural mode in such cases is more excited compared with the partially correlated or uncorrelated rail irregularities. Therefore, the ride quality index in completely correlated cases is higher than other cases.

Passenger Train Slipstream Characterization Using a Rotating Rail Rig

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
N. Gil ◽  
C. J. Baker ◽  
C. Roberts ◽  
A. Quinn
Keyword(s):  
Boundary Layer ◽  
Turbulence Intensity ◽  
High Speed ◽  
Scale Model ◽  
High Speed Train ◽  
Measuring Time ◽  
Displacement Thickness ◽  
Time Histories ◽  
Attached Flow ◽  
Good Agreement

This paper presents the results of a new experimental technique to determine the structure of train slipstreams. The highly turbulent, nonstationary nature of the slipstreams make their measurement difficult and time consuming as in order to identify the trends of behavior several passings of the train have to be made. This new technique has been developed in order to minimize considerably the measuring time. It consists of a rotating rail rig to which a 1/50 scale model of a four car high speed train is attached. Flow velocities were measured using two multihole Cobra probes, positioned close to the model sides and top. Tests were carried out at different model speeds, although if the results were suitably normalized, the effect of model speed was not significant. Velocity time histories for each configuration were obtained from ensemble averages of the results of a large number of runs (of the order of 80). From these it was possible to define velocity and turbulence intensity contours along the train, as well as the displacement thickness of the boundary layer, allowing a more detailed analysis of the flow. Also, wavelet analysis was carried out on different runs to reveal details of the unsteady flow structure around the vehicle. It is concluded that, although this methodology introduces some problems, the results obtained with this technique are in good agreement with previous model and full scale measurements.

Vibration Analysis of Vehicle-Rail System under the Condition of Track Stiffness Irregularity

2013 ◽  
Vol 368-370 ◽  
pp. 1431-1437 ◽  
Author(s):  
Tian Yu Lu ◽  
Zu Jun Yu ◽  
Hong Mei Shi
Keyword(s):  
Frequency Spectrum ◽  
Vibration Frequency ◽  
Vibration Analysis ◽  
High Speed ◽  
Track Structure ◽  
High Speed Train ◽  
Track Maintenance ◽  
Rail System ◽  
Coupling System ◽  
Track Stiffness

The interaction of track structure and high-speed train has greater impact on safe and steady running of the trains. This paper obtained acceleration and frequency spectrum of the train's running vibration in the case of sleeper’s spacing and continuous failure， and continuous and spacing loose tie by establishing the vertical model of vehicle-track coupling system, and analyzed the sleeper failure and loose tie which has a greater impact on the 40-80 Hz vibration frequency of the train, which provided a basis for track maintenance.

Effect of Long-Term Bridge Deformations on Safe Operation of High-Speed Railway and Vibration of Vehicle–Bridge Coupled System

2019 ◽  
Vol 19 (09) ◽  
pp. 1950111 ◽  
Author(s):  
Hongye Gou ◽  
Longcheng Yang ◽  
Zhixiang Mo ◽  
Wei Guo ◽  
Xiaoyu Shi ◽  
...  
Keyword(s):  
High Speed ◽  
Measurement Data ◽  
Coupled System ◽  
Bridge Pier ◽  
Railway Track ◽  
Vertical Acceleration ◽  
High Speed Train ◽  
High Speed Trains ◽  
Track Deformation

Operation safety of high-speed trains is dependent on their vibration characteristics, which vary with bridge deformation. This paper studies the influence of bridge pier settlement and girder creep camber, which are two typical types of long-term bridge deformation, on the vibration of high-speed trains. To this end, an analytical approach is presented to link the bridge deformation with railway track deformation; the track deformation is used to analyze the vibration of the CRH2 high-speed train in China. The vibration analysis results are validated using the in-situ measurement data. The present study shows that bridge pier settlement greatly affects the vertical acceleration, derailment coefficient and wheel unloading rate of the high-speed train; incorporating bridge girder camber aggravates the vibration of the train–bridge system. The threshold of bridge pier settlement is suggested to be 11.1[Formula: see text]mm for trains moving at 350[Formula: see text]km/h with regard to the code-specified vibration limit. This study has significant implications for the design and operation of high-speed railways.

Influence of a flexible wheelset on the dynamic responses of a high-speed railway car due to a wheel flat

2017 ◽  
Vol 232 (4) ◽  
pp. 1033-1048 ◽  
Author(s):  
Xingwen Wu ◽  
Subhash Rakheja ◽  
AKW Ahmed ◽  
Maoru Chi
Keyword(s):  
Dynamic Response ◽  
Dynamic Model ◽  
High Speed ◽  
Dynamic Responses ◽  
Vertical Acceleration ◽  
High Speed Train ◽  
Multibody Dynamic ◽  
Flexible Track ◽  
Wheel Flat ◽  
Track Slab

Large magnitude impact loads caused by wheel flats may excite various vibration modes of wheelsets employed in high-speed trains and thereby contribute considerably to the dynamic response of vehicles. In this study, the wheelset is modeled as a flexible body using the modal approach, which is integrated to a multibody dynamic model of the high-speed train coupled with a flexible track slab model. The multibody dynamic model is formulated for a typical high-speed train consisting of a car body, two bogie frames, and four wheelsets. The track is modeled considering the rail as a Timoshenko beam discretely supported on a flexible track slab. The effects of the wheelset flexibility on the dynamic response are illustrated through comparisons with those obtained with a rigid wheelset considering different vehicle speeds and sizes of the wheel flat. Subsequently, the effects of wheel flats on the vehicle–track system are evaluated in terms of the wheel–rail impact forces, axle-box vertical acceleration, and dynamic stress developed in the wheelset due to a haversine wheel flat. The results suggest that the wheelset flexibility can lead to significantly higher axle-box vibration and wheelset axle stress compared to a rigid wheelset in the presence of a wheel flat.

Research into the Parameter Influence on Coupled Vibration Analysis of High Speed Train and Bridge

2011 ◽  
Vol 90-93 ◽  
pp. 884-889
Author(s):  
Chang Jian Tan ◽  
Wen Hong Ji
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Railway Track ◽  
Vertical Acceleration ◽  
High Speed Train ◽  
Coupled Vibration ◽  
Train Speed ◽  
Response Increase ◽  
Track Irregularity ◽  
Parameter Influence

To investigate the characteristic of coupled vibration of high speed train and bridge, the effect of the railway track irregularity, different train speeds were investigated based on analyzing the coupled vibration of the JR300 high speed train-bridge system The results show that the vertical acceleration of train will be influenced much when the railway track irregularity is considered. The study suggests that the dynamic response of the train and bridge decreases with an increase in the train speed, when the train speed is at a certain zone, and the dynamic response increase rapidly with the increased train speed when the train speed is out of this zone.

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