scholarly journals Research on Load Characteristics of Axle-Box Bearing Raceway under Wheel-Rail Excitation

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xiaokang Liao ◽  
Cai Yi ◽  
Fengyu Ou ◽  
Yi Zhang ◽  
Zili Chen ◽  
...  
Keyword(s):  
Working Conditions ◽  
High Speed ◽  
Dynamic Performance ◽  
Field Tests ◽  
Contact Load ◽  
Dynamic Interactions ◽  
Load Characteristics ◽  
Track Irregularity ◽  
The Impact ◽  
Excitation Conditions

With the increasing speed of high-speed trains, the service conditions of axle-box bearing system worsen, and meanwhile, the dynamic performance of the axle-box bearing directly affects the operational safety. However, the dynamic interactions of the axle-box bearing in the traditional vehicle-track system are often ignored. In this paper, a vehicle-track coupling dynamic model considering axle-box bearing has been built, and the effectiveness of the model is proved by field tests. Dynamic performance of the axle-box bearing has been analyzed and discussed through numerical simulations under different working conditions. Comparing the roller-raceway contact load characteristics under different working conditions, results show that the peak values of roller-outer raceway contact load with wheel-polygonal excitation are basically the same with those without wheel-rail excitation. However, most of the peak values of roller-outer raceway contact force under track irregularity and comprehensive excitation conditions are far greater than those under wheel-polygonal excitation and no wheel-rail excitation conditions, which indicates that the impact of track irregularity on the contact load is dominant.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

scholarly journals Impact of fractional order methods on optimized tilt control for rail vehicles

2017 ◽  
Vol 20 (3) ◽  
Author(s):  
Fazilah Hassan ◽  
Argyrios Zolotas
Keyword(s):  
Fractional Order ◽  
High Speed ◽  
Control Design ◽  
Ride Quality ◽  
Dynamic Interactions ◽  
High Speed Rail ◽  
Control Applications ◽  
Railway Systems ◽  
Methods Analytical ◽  
The Impact

AbstractAdvances in the use of fractional order calculus in control theory increasingly make their way into control applications such as in the process industry, electrical machines, mechatronics/robotics, albeit at a slower rate into control applications in automotive and railway systems. We present work on advances in high-speed rail vehicle tilt control design enabled by use of fractional order methods. Analytical problems in rail tilt control still exist especially on simplified tilt using non-precedent sensor information (rather than use of the more complex precedence (or preview) schemes). Challenges arise due to suspension dynamic interactions (due to strong coupling between roll and lateral dynamic modes) and the sensor measurement. We explore optimized PID-based non-precedent tilt control via both direct fractional-order PID design and via fractional-order based loop shaping that reduces effect of lags in the design model. The impact of fractional order design methods on tilt performance (track curve following vs ride quality) trade off is particularly emphasized. Simulation results illustrate superior benefit by utilizing fractional order-based tilt control design.

Reduction of ground-borne vibrations from rail lines on viaducts by means of elastic anti-vibration mats

2018 ◽  
Vol 233 (5) ◽  
pp. 550-565
Author(s):  
Caiyou Zhao ◽  
Wang Ping ◽  
Mengting Xing ◽  
Qiang Yi ◽  
Liuchong Wang
Keyword(s):  
High Speed ◽  
Reaction Force ◽  
Field Tests ◽  
Ground Vibration ◽  
Coupling System ◽  
Step Procedure ◽  
Measurement Results ◽  
Track Bridge ◽  
Bridge Bearing ◽  
The Impact

In this paper, the effectiveness of elastic anti-vibration mats in reducing ground-borne vibrations from rail viaducts is investigated by means of theoretical analysis and is validated by the results of field tests. A two-step procedure is adopted for analyzing the vehicle-track-bridge-soil coupling system. In the first step, the train-track-bridge-pier subsystem is considered, and the bridge-bearing reaction force is solved. In the second step, the pier-pile-soil subsystem is considered, and the ground vibration solution is obtained by applying the negative bridge-bearing reaction force to the pier top on a pier-pile-soil model. The accuracy of the presented model is then verified in comparison with in-situ measurement results. On the basis of this comparison, a parametric study on the impact of anti-vibration mats on ground-borne vibrations was investigated theoretically, and the effectiveness of elastic anti-vibration mats with the suggested optimal parameters was further validated by field tests. The results show that when the stiffness of the elastic anti-vibration mats is 1.5 MPa/m, ground vibration decreases significantly and the vertical rail displacement agrees with high-speed railway regulations.

Dynamics modeling and analysis of a four-wheel independent motor-drive virtual-track train

2020 ◽  
pp. 146441932096401
Author(s):  
Zhonghui Yin ◽  
Jiye Zhang ◽  
Haiying Lu ◽  
Weihua Zhang
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Spatial Dynamics ◽  
Dynamic Responses ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Coupling Effects ◽  
Dynamic Interactions ◽  
Modeling And Analysis

Due to urbanisation and the economic challenges of traffic, it is urgently necessary to develop an environmentally friendly virtual-track train with suitable speed, high load capacity and low construction cost in China. To guide the design and evaluate this train’s dynamic behaviour, a spatial-dynamics model has been developed based on the dynamics theory and tyre-road interaction. The proposed dynamics model comprises mechanical vehicle systems, traction and braking characteristics and tyre-road dynamic interactions. The coupling effects amongst those systems of virtual track train are derived theoretically for the first time. The nonlinear characteristics of the tyre are modelled by the transit tyre-magic formula with consideration of road irregularities. Based on a designed PID controller and the comprehensive dynamics model, the dynamic performance of the system can be revealed considering motion coupling effects and complicated excitations, especially under traction and braking conditions. The dynamic responses of whole virtual track train can be obtained by numerical integration under different conditions. The vibration characteristics of such train are assessed under running at a constant speed and during the traction/braking process. The results show that the vibrations of the vehicle system are significantly influenced by road irregularities, especially at high speed ranges. The motions and vibrations of different components are intensive coupled, which should not to be neglected in the dynamics assessment of the virtual track train. Besides, the dynamics model can also be applied to dynamics-related assessment (fatigue, strength and some damage conditions, et al.) and parameter optimisation of the virtual-track train.

Full scale field testing of temporary rockfall protection measures

2020 ◽  
Author(s):  
Axel Volkwein ◽  
Florian Hofstetter ◽  
Marc Hauser
Keyword(s):  
High Speed ◽  
Minimum Weight ◽  
Field Tests ◽  
Front Surface ◽  
Frame Rate ◽  
Slope Surface ◽  
Retention Capacity ◽  
Protection Measures ◽  
The Impact ◽  
Rockfall Protection

<p>Temporary rockfall protection measures are often implemented by using so-called steel palisades. Such elements can described as a steel surface that is supported perpendicular to the slope surface. In the present case, several sheet piling sections are welded onto a steel frame to form an area 1.5m high and 3m long. At the lateral edges of the surface, steel sections, welded together to form a triangle, create the support of the front surface, so that one side of the triangle is parallel to the impact surface and another side is parallel to the slope surface. At the corners close to the ground, massive steel spikes allow penetration into the ground. The weight of a palisade is about 900kg. An example of such a palisade can be found in [1].</p><p>The above barriers are in usage since many years. However, their rockfall energy retention capacity has never been evaluated yet. For that reasons, the Swiss Federal Railways launched a project for a deeper understanding of the performance of the palisades; for an adequate selection of the protection measures and a reliable risk analyses with respect to the variety of rockfall events that can be expected at a specific construction site and might cause failure of a structure.</p><p>Failure limits of the palisades are expected regarding the following failure scenarios:</p><ul><li>tilting of the barrier over the valley side steel spikes</li> <li>displacement of the barrier due to insufficient action of the steel spikes</li> <li>failure of the front surface</li> </ul><p>In this contribution, the above mechanisms are evaluated by means of 1:1 field tests.  A detailed analysis of performance and failure states will be provided. Furthermore, potential solutions for simple but effective reinforcement of the barriers are discussed.</p><p>The field tests were carried out on a slope inclined at an angle of about 30 degrees. Test blocks with a minimum weight of 240kg are thrown onto the palisades with the help of a forestry cableway reaching impact speeds of up to 25m/s. The impact energies vary from 12 to 100 kJ. Impact location and impact speed are determined by means of laterally taken high-speed video records with a frame rate of up to 1000fps and a resolution of 800x600pxs. Furthermore, the accelerations in the test body were measured at 1000Hz and – for some of the tests - the acting anchorage forces at 5000Hz.</p><p> </p>

Dynamic-Performance Research of Placement Machine

2010 ◽  
Vol 44-47 ◽  
pp. 641-645 ◽  
Author(s):  
Yong Shan Xiao ◽  
Fu Min Song ◽  
Qiang Fang
Keyword(s):  
Working Conditions ◽  
Dynamic Performance ◽  
Simulation Method ◽  
Structure Form ◽  
Dynamic Accuracy ◽  
Controlling System ◽  
Placement Machine ◽  
Stiffness And Damping ◽  
The Impact ◽  
Performance Research

The placement machine was simulated by multidisciplinary co-simulation method in various working conditions, and its dynamic accuracy was studied by simulation. According to the structure form of the placement machine, the virtual prototype for co-simulation was built. The impact of all sorts of parameters on the system dynamic accuracy was simulated including the stiffness and damping of the slider and the shaft coupling, the friction coefficient and the mass distribution etc. The result shows this method is able to predict the dynamic performance and the control margin of the whole machine, instruct the design optimization and the selection, and provide the good design thought and direction for the matching design of the machinery and controlling system.

An Area-Based Faulting Measurement Method Using Three-Dimensional Pavement Data

2018 ◽  
Vol 2672 (40) ◽  
pp. 41-49 ◽  
Author(s):  
Georgene M. Geary ◽  
Yichang (James) Tsai ◽  
Yiching Wu
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Field Tests ◽  
Automatic Testing ◽  
Specific Method ◽  
Concrete Pavements ◽  
Federal Highway ◽  
Manual Testing ◽  
The Impact ◽  
Departments Of Transportation

Faulting is one of the three performance measures recognized by the Code of Federal Regulations (CFR) for jointed concrete pavements. U.S. Federal Highway Administration rules developed for the CFR require the state Departments of Transportation to use the AASHTO Standard R 36, Standard Method for Evaluating Faulting of Concrete Pavements, for measurement of faulting. R 36 allows both manual testing using a faultmeter and automatic testing using a high-speed inertial profiler (HSIP). There is a concern in the literature that the HSIP methods are not accurate enough for network level testing of faulting. Recent studies have also shown that three-dimensional (3-D) laser technology is showing promise for providing more accurate faulting measurements. Still, there currently is not a specific method in R 36 that utilizes 3-D data for gathering faulting measurements. This paper proposes a new method that takes full advantage of the full-coverage capabilities of 3-D to measure faulting more accurately and consistently. This method uses the comparison of smoothed areas on both sides of a joint instead of a single longitudinal profile to measure elevation differences. Field tests were performed to compare the 3-D method with manual readings taken with a Georgia faultmeter on two sections of interstate in Georgia. In addition, the impact of various footprints and measuring locations of faulting measurements using this 3-D technology were quantitatively evaluated using the proposed method. Based on this case study the new proposed 3-D method appears to be appropriate to be considered to be added as a 3-D automatic method in AASHTO R 36.

scholarly journals ANALYSIS OF THE IMPACT OF SPECIAL CONSTRUCTIONS OF GAP SEALS ON THE DYNAMICS OF CENTRIFUGAL MACHINES

ScienceRise ◽  
2020 ◽  
pp. 3-13
Author(s):  
Serhii Shevchenko
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Operating Conditions ◽  
Centrifugal Pumps ◽  
Labyrinth Seals ◽  
Research Results ◽  
The Impact ◽  
Technological Product

The object of research: the influence of the design features of special gap seals on the dynamic characteristics of centrifugal machines. Investigated problem: harmonization of the consumption and dynamic characteristics of the seals of the rotors of high-speed machines by applying special design methods. Main scientific results: The mechanism and operating conditions of seals with floating rings are described. It is determined that the most effective from the point of view of dynamic characteristics is the variant of the semi-movable ring. Expressions for determining the conditions of angular and radial immobility of a floating ring are obtained. The design options for deformable gap seals, including deformable floating rings, deformable interwheel seals and seals with an axially movable deformable sleeve, have been investigated. The scope of their application for unique machines with high requirements for tightness and vibration reliability has been determined. Variants of the design of labyrinth seals have been investigated. The analysis shows that the dynamic properties of labyrinth seals significantly depend on the relative position of the ridges. Overlapping ridged seals have the worst dynamic performance of the labyrinth seal designs. The honeycomb seal has more favorable dynamic properties, and the well seal has the best combination of consumption and dynamic characteristics. The dynamic characteristics are especially important for the seals of high-speed rotors of centrifugal machines. The area of practical use of the research results: Enterprises that manufacture centrifugal machines: pumps and compressors. Innovative technological product: a methodology for the selection, design and calculation of special designs of gap seals with optimization of dynamic and flow characteristics. Scope of application of the innovative technological product: The obtained research results will be useful in the design and manufacture of centrifugal pumps and compressors for any parameters.

scholarly journals The Impact of Time Delays for Power Hardware-in-the-Loop Investigations

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3154
Author(s):  
Jana Ihrens ◽  
Stefan Möws ◽  
Lennard Wilkening ◽  
Thorsten A. Kern ◽  
Christian Becker
Keyword(s):  
Time Delays ◽  
Field Tests ◽  
General Concept ◽  
Hardware In The Loop ◽  
Dynamic Interactions ◽  
Case Examples ◽  
System A ◽  
Grid Interface ◽  
The Impact ◽  
Critical Process

Power hardware-in-the-loop (PHiL) simulations provide a powerful environment in the critical process of testing new components and controllers. In this work, we aim to explain the impact of time delays in a PHiL setup and recommend how to consider them in different investigations. The general concept of PHiL, with its necessary components, is explained and the benefits compared to pure simulation and implemented field tests are presented. An example for a flexible PHiL environment is shown in form of the Power Hardware-in-the-Loop Simulation Laboratory (PHiLsLab) at TU Hamburg. In the PHiLsLab, different hardware components are used as the simulator to provide a grid interface via an amplifier system, a real-time simulator by OPAL-RT, a programmable logic controller by Bachmann, and an M-DUINO microcontroller. Benefits and limitations of the different simulators are shown using case examples of conducted investigations. Essentially, all platforms prove to be appropriate and sufficiently powerful simulators, if the time constants and complexity of the investigated case fit the simulator performance. The communication interfaces used between simulator and amplifier system differ in communication speed and delay; therefore, they have to be considered to determine the level of dynamic interactions between the simulated rest of system and the hardware under test.

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