scholarly journals Experimental Study of Railway Trackbed Pressure Distribution Under Dynamic Loading

2019 ◽  
Vol 14 (4) ◽  
pp. 504-520
Author(s):  
Mykola Sysyn ◽  
Vitalii Kovalchuk ◽  
Olga Nabochenko ◽  
Yuri Kovalchuk ◽  
Oleg Voznyak
Keyword(s):  
Experimental Study ◽  
Pressure Distribution ◽  
Dynamic Loading ◽  
Railway Track ◽  
Rolling Stock ◽  
Video Observation ◽  
Pressure Measurements ◽  
Optimal Conditions ◽  
Load Cells ◽  
The Impact

Reliable and durable operation of the railway track under the dynamic load of the rolling stock depends considerably on the ability of the ballast layer to get the load from the sleepers and distribute it to the subgrade. In this paper, the experimental study of the distribution properties of the ballast layer under the impact of dynamic loading depending on the density of the ballast layer is carried out. The ballast behaviour during load cycles is estimated by pressure measurements at the ballast prism base along the axis of a sleeper with simultaneous video observation of the ballast particles movement through transparent sidewalls of the box with crushed stone. Measurements of pressure distribution are carried out with the developed microcontroller system of measurements and developed load cells. The system allows performing multi-point measurements of stress in combination with measurements of acceleration and photogrammetry. The results of measurements showed a significant effect of the ballast layer consolidation on the distribution of stresses under the sleeper. The performed research opens up opportunities for practical improvement of the existing types of track structures and the technology of the ballast layer tamping in terms to provide the optimal conditions for the ballast layer operation.

scholarly journals Railway Track Stress–Strain Analysis Using High-Precision Accelerometers

2021 ◽  
Vol 11 (24) ◽  
pp. 11908
Author(s):  
Alexandr Avsievich ◽  
Vladimir Avsievich ◽  
Nikita Avsievich ◽  
Dmitry Ovchinnikov ◽  
Anton Ivaschenko
Keyword(s):  
High Precision ◽  
Strain Analysis ◽  
Railway Track ◽  
Rolling Stock ◽  
Mathematical Methods ◽  
Stress Strain ◽  
Technical Parameters ◽  
The Impact ◽  
The Internet Of Things ◽  
Track Line

We propose a new approach for railway path diagnostics on the basis of track line stress–strain analysis using the data provided by high-precision accelerometers. This type of sensor provides sufficient accuracy with lower costs, and enables the development of a railway digital twin, according to the concept of the Internet of Things. The installation of sensors on a railway track along its entire length allows real-time monitoring of the states of the technical parameters of the railway track, and using mathematical methods to evaluate its wear on the basis of constantly received data. This paper presents an original 3D model of a railway track line and the results of its analysis using a finite element method. To test the model, we performed an analysis of the normal stresses and deformations in the elements of a railway track by simulating the impact of rolling stock on a section of a railway track with intermediate rail fastenings, ZhBR-65SH. The research results were probated and tested at the testing ground of the Kuibyshev branch of Russian Railways, the Samara track. The proposed approach makes it possible to determine the load of the track, and knowing the movement of the rail, to calculate the structural stress in the elements of the railway track, to constantly monitor the parameters of the slope and rail subsidence.

scholarly journals Life Cycle Cost Evaluation of Noise Control Methods at Urban Railway Turnouts

2016 ◽  
Author(s):  
Rodrigo Tavares De Freitas ◽  
Sakdirat Kaewunruen
Keyword(s):  
Life Cycle ◽  
Life Cycle Analysis ◽  
Cost Evaluation ◽  
Railway Track ◽  
Rolling Stock ◽  
Noise And Vibration ◽  
Impact Noise ◽  
Wide Range ◽  
Mitigation Methods ◽  
The Impact

The railway industry focus in the past years was to research, find and develop methods to mitigate noise and vibration resulted from wheel/rail contact along track infrastructure. This resulted in a wide range of abatement measures that are available for the professionals of the industry today. However, although there are many options in the market, their practical implementations depend upon general constraints that affect most technological application in the engineering world. The progression of these technologies have facilitated the selection of more adequate methods for each best case scenario, but further studies are ought to be made to proper assess if each one is fit for their purpose. Every method implementation must be analyzed through budget and timeframe limitations, which includes building, maintenance and inspection costs and time allocation, while also aiming to meet different benefits, such as environmental impact control and wear of the whole infrastructure. There are several situations and facilities in a railway project design that need noise and vibration mitigation methods and each design allocates different priorities for each one of them. Traditionally the disturbance caused by railways to the community are generated by wheel/rail contact sound radiation that expresses in different ways, depending on the movement of the rolling stock and track alignment, such as rolling noise, impact noise and curve noise. More specifically, in special trackworks such as turnouts, the main area of this study, there are two noises types that must be evaluated: impact noise and screeching noise. With respect to the second, it is similar to curve squeals and, being such, its mitigation methods are to be assigned as if it was to abate curve squeal in turnouts and crossings. The impact noise on the other hand, emerges from the sound made by the rolling stock moving through joints and discontinuities (i.e. gaps) that composes these special components of a railway track. A life cycle analysis is therefore substantial for this reality and in this case will be applied to Squeal and Impact Noise on Special Trackwork. The evaluation is based on a valid literature review and the total costs were assumed by industry reports to maintain coherency. The period for a life cycle analysis is usually of 50 years, hence it was the value assumed. As for the general parameters, an area with high density of people was considered to estimate the values for a community with very strict limits for noise and vibration.

scholarly journals Permissible Values of the Dynamic Impact of the Rolling Stock on the Railway Track in the Case of Axle Load Increase

2021 ◽  
pp. 15-23
Author(s):  
О. M Patlasov ◽  
Y. M Fedorenko
Keyword(s):  
Dynamic Effect ◽  
Field Measurements ◽  
Experimental Tests ◽  
Railway Track ◽  
Rolling Stock ◽  
Actual State ◽  
Dynamic Force ◽  
Dynamic Impact ◽  
Railway Line ◽  
The Impact

Purpose. The study is aimed at determining experimentally the values of the parameters characterizing the dynamic effect of rolling stock on the railway track, substantiating the maximum permissible (limiting) values. Methodology. To investigate the interaction between the track and the rolling stock, the devices to record various physical processes were installed on the experimental sections. The devices were installed in 8 sections along the outer railway line. To establish the actual state of the track, field measurements were carried out in accordance with the Program and research methodology. Findings. According to the results of experimental tests of the impact on the track, it was revealed that the average vertical loads, and, accordingly, the average vertical deformations, under the cars with an axle load of up to 25 tf/axle are higher than that under the cars with an axle load of up to 23.5 tf/axle by 8 percent. The maximum vertical loads under the cars with an axle load of 25 tf/axle exceeded the average loads by 10.0 tf, and under the cars with an axle load of up to 23.5 tf/axle exceeded the average values by 12.8 tf. During the tests, no cars were found in which the vertical dynamic force exceeds 20 tf, and the horizontal force exceeds 10 tf. Therefore, the norms of permissible dynamic impact can be taken in accordance with the Regulations on Preventive Maintenance and Repair Track Work on the Railways of Ukraine. Originality. The authors conducted a study to assess the dynamic characteristics of the interaction of track and rolling stock, in particular the stresses in the edges of the rail base, vertical and horizontal forces from the wheels of rolling stock. Practical value. On the basis of the results obtained, it is possible to estimate the permissible values of the dynamic effect of the rolling stock on the railway track to substantiate the need to change the standards for the material consumption of the track superstructure and labor. In turn, this will make it possible to plan the repair and track periods more economically and according to the actual indicators of the state of the track superstructure.

scholarly journals Elastic characteristics of the underrail base of a ballastless railway track

2021 ◽  
Vol 2021 (4) ◽  
pp. 469-479
Author(s):  
Alexey F. KOLOS ◽  
◽  
Ksenia I. IVANOVA ◽  
Keyword(s):  
Practical Importance ◽  
Operating Conditions ◽  
Railway Track ◽  
Rolling Stock ◽  
Relative Stiffness ◽  
Ballastless Track ◽  
Full Scale Tests ◽  
The Impact ◽  
Track Modulus ◽  
Elastic Characteristics

Objective: Experimental determination track modulus and the coeffi cient of relative stiffness of underrail base and the rail, which are the main elastic characteristics that determine the stresses in the structural elements of track superstructure under the impact force from the train. The values of these parameters for a track with a ballast layer are well studied, in contrast to a ballastless track. Comparison of the elastic characteristics of a ballastless railway track with analogs of a track on ballast, as well as an assessment of their effect on the stress-strain state of the superstructure elements of a ballastless track. Methods: When carrying out full-scale tests, strain-gauge methods for measuring stresses in the elements of the track superstructure were used. The obtained values were processed by the methods of mathematical statistics. One statistical series included the values of stresses corresponding to one type of rolling stock, fi xed axle load and train speed, changing by no more than 10 km/h. The probability level in processing the results was taken in all cases equal to 0,994. Results: The values of track modulus and the coeffi cient of the relative stiffness of the underrail base and the rail were obtained for a ballastless structure of the RHEDA 2000 type. Practical importance: The results allow us to consider the rail as a beam lying on a solid elastic foundation in relation to the ballastless track and use the existing calculation methods for the design of ballastless track structures depending on the operating conditions.

Experimental Study on Extraction of Scandium from Complex Silicate Ore

2013 ◽  
Vol 734-737 ◽  
pp. 1037-1040
Author(s):  
Qing Rong Yang ◽  
Gui Fang Zhang ◽  
Peng Yan
Keyword(s):  
Experimental Study ◽  
Organic Phase ◽  
Mixing Time ◽  
Extraction Rate ◽  
Impact Factors ◽  
Optimal Conditions ◽  
Extractant Concentration ◽  
Leaching Experiments ◽  
The Impact ◽  
Extraction Agent

Based on leaching experiments of complex silicate ore contenting scandium, the research has adopted extraction to concentrate scandium and separate impurity. The emphasis of this reaserch is the impact factors, so the experiments including extractant concentration, organic aqueous ratio, mixing time, organic phase washing, organic phase reextraction, have been conducted. The optimal conditions are that the concentration of extraction is 25%, the O/A is 1:10, the mixing time is 3min, the washing time is 3, the O/A of reextraction is 1:2.3, and the extraction rate of exceeding 98% and reextracion rate of 99.01% were obtained when adopting P501 as the extraction agent.

Develop a New Approach Measuring the Wheel/Rail Interaction Loads

2021 ◽  
Author(s):  
Yuriy Boronenko ◽  
Rustam Rahimov ◽  
Waail Mahmod Lafta
Keyword(s):  
Heavy Traffic ◽  
Lateral Force ◽  
Railway Track ◽  
Rolling Stock ◽  
Strain Gauges ◽  
Lateral Impact ◽  
Railway Engineering ◽  
The Right ◽  
And Control ◽  
The Impact

Abstract Determine and control the impact of rolling stock on the railway track, one of the significant subjects of railway engineering, especially with heavy traffic and innovative freight cars with increased axle loads. Different methods utilized to measure the lateral impact of rolling stock on a railway based on the use of strain gauges installed on the rail differ in the location of strain gauges and the specifics of processing the received signals. The shortage of these methods that the lateral force arising from the wheel/rail interaction determined when the wheel position over the strain gauges sections. Therefore, continuous registration of details in the wheel/rail contact is impossible. Multiple passes of the test rolling stock along the measuring section are required to receive the right results. In this article, a new method developed to continue recording the lateral forces of the wheel/rail interaction by measuring stresses in two sections of the rail on a significant part of the sleeper space. The railway track experiments approved this method’s ability to restore the lateral force of not more than 4% standard deviation along the measuring zone’s length and increased the volume of reliable statistical data obtained, improved the measurement accuracy, and reduced the time and cost.

Experimental study of thermohydraulic characteristics and irreversibility analysis of novel axial corrugated tube with spring tape inserts

2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Thermal Performance ◽  
Working Fluid ◽  
The Novel ◽  
Heat Exchanger Tube ◽  
Heat Transfer Augmentation ◽  
Corrugated Tube ◽  
The Impact ◽  
Exchanger Tube

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.

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