scholarly journals ASPECTS OF BRAKING EFFICIENCY CRITERIA FOR FREIGHT WAGONS UNDER THE LATEST RULES OF HOST 34434-18

2021 ◽  
pp. 22-30
Author(s):  
Oleksandr Safronov ◽  
◽  
Yurii Vodiannikov ◽  
Keyword(s):  
Axial Load ◽  
Axial Loads ◽  
Pressure Force ◽  
Significant Discrepancy ◽  
Freight Train ◽  
Pressing Force ◽  
Technical Requirements ◽  
Actual Force ◽  
Braking Distance ◽  
Freight Wagons

The paper deals with the analysis of the braking efficiency criteria for freight trains formed with wagons that have increased axle load up to 294.3 kN (30 ts) when moving at speeds up to 120 km/h inclusive. Increasing the efficiency of freight trains by increasing the technical and economic performance of cars by increasing the axial load to 294.3 kN (30 ts) and train speeds up to 160 km/h led to the development of technical requirements and rules for braking systems set out in HOST 34434-18. According to the new rules and requirements, the following are accepted as criteria for the braking efficiency of freight wagons, that is, up to the maximum values of the braking distances of the freight train on the site in the specified intervals of speeds of axial loads; calculated coefficients of force of pressing of composite blocks on wheels at braking; the pressing force of the composite pads on the axis in terms of cast iron pads. The calculation of the maximum allowable value of the braking distance of the freight train is performed based on the actual pressing forces and the actual friction coefficients. The paper shows that the specific braking forces obtained using the actual pressing forces exceed the calculated specific braking forces using the calculated coefficients. Based on the above-mentioned, it is concluded that the braking efficiency criteria with reference to the maximum allowable values of the braking distances and the calculated coefficients of the pressing force have a significant discrepancy between each other. It is proposed to use the actual pressure force coefficients instead of the calculated coefficients to assess the braking efficiency of the freight train. The paper presents the permissible values of the actual force values of pressing the pads on the wheels for wagons with axial load (230.5 - 294.3) kN at speeds up to 120 km/h inclusive, for which the braking distance criterion of the freight train is observed. Key words: criterion, braking efficiency, freight train, axial load, braking distance, specific braking force, calculated coefficients, actual coefficient.

scholarly journals SOFTWARE APPLICATION FOR DETERMINATION OF BRAKE EFFICIENCY OF FREIGHT TRAINS ACCORDING TO THE RULES OF GOST 34434-2018

2020 ◽  
pp. 107-119
Author(s):  
O.M. Safronov ◽  
◽  
Y.Y. Vodiannikov ◽  
O.G. Makeieva
Keyword(s):  
Cast Iron ◽  
Axial Load ◽  
Disc Brake ◽  
Calculation Algorithm ◽  
Freight Train ◽  
Software Application ◽  
Technical Requirements ◽  
Complete Automation ◽  
Computational Research

Calculation algorithm for braking distances of a freight train and recalculation on cast iron brake shoes in accordance with new rules of GOST 34434-2018 "BRAKE SYSTEMS OF FREIGHT CARS. Technical requirements and calculation rules " is given. According to the above mentioned algorithms, a program was drawn up in the Excel environment, intended to complete automation of the process of computational research to determine the braking efficiency of a freight train. The program is universal, as it allows studying brake systems of different design: with one and two brake cylinders; with one-sided and two-sided application of brake shoes on wheels; with disc brake. Examples of calculation studies of the braking efficiency of the open-top car with an axial load of 25 tons are shown.

scholarly journals DETERMINATION OF FREIGHT WAGON PARAMETERS ACCORDING TO THE SPECIFIED CRITERIA OF THE TRAIN BRAKING EFFICIENCY (four-axle gondola cars, covered cars, platforms, dump cars)

2021 ◽  
pp. 101-110
Author(s):  
Oleksandr Safronov ◽  
◽  
Yurii Vodiannikov ◽  
Olena Makeieva
Keyword(s):  
Axial Load ◽  
Gear Ratio ◽  
Normative Values ◽  
Power Relationship ◽  
Freight Train ◽  
Braking Performance ◽  
Brake Pads ◽  
Braking System ◽  
Braking Distance

The lack of normative values of the actual coefficients in the new rules of HOST 34434-2018 do not allow to implement and determine the optimal characte-ristics of the brake according to pre-accepted conditions of braking efficiency (braking distance), which causes uncertainty in solving this problem. The uncertainty is that the choice of characteristics of the braking system of the freight wagon has to be done by searching a large number of options. In this regard, the paper provides tools for determining the actual pressing force of the brake pads on the wheels, which complies with the specified braking performance of the freight train. As a tool, universal formulas are used in the form of a power relationship between the actual force of the brake pads and the braking distance of the freight train. The coefficients of universal formulas are obtained on the basis of computer modeling. Numerous examples show that the error in the use of universal formulas in calculation studies does not exceed 1% compared with the calculation method according to HOST 34434-2018. The values of the actual coefficients depending on the axial load of the wagon and the speed at which the braking distances of the freight train satisfy the normative minimum allowable values are given. It is shown that calculation studies performed according to the universal formulas in the EXCEL environment allows to fully automating the computational process. A method for determining the gear ratio of the brake lever of a freight wagon, according to which the specified braking efficiency is performed, is proposed. The proposed procedure allows you to perform a variety of studies to select the optimal parameters of the braking system of freight wagons that meet the specified requirements of braking efficiency, and greatly facilitates the calculation studies. Key words: аctual coefficient, braking distance, speed, axial load, power dependence, coefficients, gear ratio.

scholarly journals Improved design criterion for frictionally engaged contacts in overrunning clutches

2021 ◽  
Author(s):  
Nadine Nagler ◽  
Armin Lohrengel
Keyword(s):  
Design Process ◽  
Contact Area ◽  
Axial Load ◽  
State Of The Art ◽  
Tangential Force ◽  
Design Criterion ◽  
Hertzian Contact ◽  
Loss Of Function ◽  
Axial Loads ◽  
Improved Design

AbstractOverrunning clutches, also known as freewheel clutches, are frictionally engaged, directional clutches; they transmit torque depending on the Freewheel clutch rings’ rotation directions. The torque causes a tangential force in the Hertzian contact area. The hitherto “state-of-the-art design criterion” bases on this load situation. In practice, axial loads additionally act on the frictionally engaged Hertzian contact area. This additional axial load can cause the loss of the friction connection and so the freewheel clutch slips. This publication presents an improved design criterion for frictionally engaged contacts in freewheel clutches. It allows to consider tangential as well as axial loads during the design process. Additionally, it offers the possibility to estimate the probability of frictional engagement loss and gross slip based on the freewheel clutch’s application scenario. This publication points out how to use the improved design criterion to design freewheel clutches that are more robust against a loss of function.

scholarly journals Comparisons Between Braking Experiments and Longitudinal Train Dynamics Using Friction Coefficient and Braking Pressure Modeling in a Freight Train

2020 ◽  
Vol 14 (1) ◽  
pp. 154-163
Author(s):  
Don Bum Choi ◽  
Rag-Gyo Jeong ◽  
Yongkook Kim ◽  
Jangbom Chai
Keyword(s):  
Friction Coefficient ◽  
Time Integration ◽  
Expansion Method ◽  
Dynamics Simulation ◽  
Dynamic Simulations ◽  
Freight Train ◽  
Emergency Braking ◽  
Braking Distance ◽  
Train Dynamics ◽  
Simulation Results

Background: This paper describes the predictions and validation of the pneumatic emergency braking performance of a freight train consisting of a locomotive and 20 wagons, generally operated in Korea. It suggests the possibility of replacing the expensive and time-consuming train running tests with longitudinal train dynamic simulations. Methods: The simulation of longitudinal train dynamics of a freight train uses the time integration method of EN 14531. For reasonable simulation results, the characteristics of the train and brake equipment must be considered. For the train characteristics, specifications provided by the vehicle manufacturer are used. The braking characteristics are analyzed by friction coefficient tests and a braking pressure model. The friction coefficients of a locomotive and wagons are tested with a dynamo test bench and statistically expanded to account for variability. Freight trains should take into account the braking delay time. To reflect this in the simulation, the brake cylinder pressure pattern model uses pressures and exponential empirical equations measured at selective positions in a train of 50 vehicles. The simulation results are validated in comparison with those of the braking tests of a freight train consisting of 1 locomotive and 20 wagons. Results: The results of the longitudinal dynamics simulation show very similar results to the running test results based on the speed profile and braking distance. Conclusion: In particular, the statistical expansion method of the friction coefficient enables robust prediction of the distribution of the braking distance. The simulation can reduce or make up for costly and time-consuming repeated braking tests and reduce the risks that may arise during testing.

scholarly journals Results of theoretical and experimental studies on determining the coefficient of subgrade reaction of sleepers for the conditions of main railways with axial loads of 30-35 tons per axle

2018 ◽  
Vol 230 ◽  
pp. 01003
Author(s):  
Oleksandr Darenskiy ◽  
Eduard Bielikov ◽  
Olexii Dudin ◽  
Alina Zvierieva ◽  
Anatolii Oleshchenko
Keyword(s):  
Sustainable Development ◽  
Reinforced Concrete ◽  
Axial Load ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Railway Track ◽  
Rolling Stock ◽  
Subgrade Reaction ◽  
Axial Loads ◽  
Interaction Dynamics

The article considers obtaining numerical values of the coefficient of subgrade reaction of wooden and reinforced concrete sleepers with axial loads up to 30-35 tons per axle. It has been concluded that using the rolling stock with axial loads of up to 35 tons per axle is necessary in order to ensure sustainable development of the railway complex. The performance of the railway track thus should be investigated in order to predict its operation in such conditions. Generally, such studies are performed using numerical methods. One of the parameters that are required for such calculations is the parameter which is commonly called the coefficient of subgrade reaction. Empirical dependencies of the coefficient of subgrade reaction of wooden and reinforced concrete sleepers on the axial load and on the operating conditions of the track have been obtained. The obtained results can be used in studies of the interaction dynamics of the track of main railways with rolling stock with axial loads of 30-35 tons per axle, which will give an opportunity to provide well-grounded recommendations on the rules for the arrangement and maintenance of the track in such conditions.

scholarly journals Transverse Deformation of Pressurised Pipes With Different Axial Loads

2017 ◽  
Author(s):  
Martin Kristoffersen ◽  
Tore Børvik ◽  
Magnus Langseth ◽  
Håvar Ilstad ◽  
Erik Levold
Keyword(s):  
Internal Pressure ◽  
Axial Load ◽  
Tensile Load ◽  
Displacement Curve ◽  
Design Codes ◽  
Axial Loads ◽  
Axial Tensile ◽  
Local Dent ◽  
Force Displacement ◽  
Good Agreement

Pipelines residing on the seabed are exposed to various hazards, one of them being denting, hooking and release of the pipeline by e.g. anchors or trawl gear. As a pipeline is displaced transversely in a hooking event, an axial tensile load resisting the displacement builds up in the pipeline. This study examines the effect of applying three different axial loads (zero, constant, and linearly increasing) to a pipe while simultaneously deforming it transversely. A fairly sharp indenter conforming to the prevailing design codes was used to deform the pipes. These three tests were repeated with an internal pressure of about 100 bar for comparison. Adding an axial load appeared to increase the pipe’s stiffness in terms of the force-displacement curve arising from deforming the pipe transversely. The internal pressure also increased the stiffness, and produced a more local dent in the pipe compared with the unpressurised pipes. All tests were recreated numerically in finite element simulations. Generally, the results of the simulations were in good agreement with the experiments.

scholarly journals Calculation of the dependence of friction coefficient of locomotive composite ridge brake shoes on pressing force and braking speed

2021 ◽  
Vol 79 (6) ◽  
pp. 337-342
Author(s):  
A. E. Gabidullin ◽  
D. V. Gorskiy ◽  
I. V. Nazarov ◽  
V. A. Nikitin
Keyword(s):  
Cast Iron ◽  
Friction Coefficient ◽  
High Wear Resistance ◽  
Electric Locomotive ◽  
Brake Shoe ◽  
Pressing Force ◽  
Frictional Properties ◽  
High Speeds ◽  
Braking Distance ◽  
Service Departments

JSC “FRITEX” has developed non-asbestos ridge composite brake shoes UR 01-01 with a reduced coefficient of friction, which, in contrast to the cast iron ridge brake shoes currently used on locomotives, have high wear resistance and more stable frictional properties at high speeds. They are much lighter than traditional cast iron shoes, resulting in lower logistics costs and easier replacement by service departments. However, the new materials used for the production of the shoe, as well as its innovative design, which combines the two types of materials, require a detailed study of its frictional properties. For this, the braking modes of a locomotive equipped with UR 01-01 shoes were simulated in a full-scale unit of a brake mechanism on an inertial stand at fixed pressures and speeds. Based on the results of the experiments, the values of the friction coefficients of the brake shoes were determined and the dependence of the friction coefficient of the shoes on the pressing force and braking speed was established. The data obtained were used in braking calculations for an electric locomotive of the VL80 series, including the determination of the braking distance, holding a single locomotive by the parking brake on a slope, and ensuring the antiskid braking due to higher values of the friction coefficient of the UR 01-01 shoe at high speeds. The composite ridge brake shoe ensures compliance with the standard values of the braking distance, antiskid braking and slope parking for the VL80 series electric locomotive. In this case, the use of these composite shoes is possible without changes in the device of the lever transmission of the electric locomotive. It is necessary to conduct running brake tests to make approbation of obtained empirical dependence of the friction coefficient of new shoes on the pressing force and the braking speed of the locomotive and its widespread use in the calculation of brake systems.

scholarly journals BRAKING EFFICIENCY OF QUARRY TRAINS WITH SIX-BOGIES DUMP CARS OF THE INCREASED AXIAL LOAD UP TO 27.7 TF

2021 ◽  
pp. 111-126
Author(s):  
Oleksandr Safronov ◽  
◽  
Yurii Vodiannikov ◽  
Pavlo Khozia ◽  
Anton Mozheiko
Keyword(s):  
Axial Load ◽  
Railway Track ◽  
Opencast Mining ◽  
Railway Transport ◽  
Maximum Slope ◽  
Industrial Enterprises ◽  
Study Results ◽  
Dump Trucks ◽  
Braking Distance ◽  
Traction Unit

Improving the technical level of railway transport of industrial enterprises is expressed in the introduction of advanced types of traction (locomotives and electric locomotives), four and six-axle specialized cars, including self-unloading, automation and telemechanics. To increase the productivity of quarry trains at PJSC "Kryukiv Railway Car Building Plant" a six-axle dump car model 33-7141 for quarry railway transport was designed. The car is designed for transportation from quarries of open cut hard rocks, ore and other bulk and lump cargo with density (1.75-4.0) t/m3, as well as mechanized unloading on dumping sites or crushing units of opencast mining. A distinctive feature of innovative dump cars from typical ones is the increase of cargo weight by 10 t and axial load to 271.6 (27.7) kN (ts). In this regard, the issues of assessing the braking efficiency of a quarry train with innovative dump cars that meet the requirements for railway industrial transport are becoming relevant. The article presents the study results of the braking efficiency of a quarry train composition of 10 and 14 cars. Locomotive TEM7 and unit OPE1AM with one and two motor cars were considered as traction units. The maximum permissible speeds were determined in a given range of slopes of the railway track, and the maximum possible descent was set provided that the braking distance does not exceed or will be equal to 300. As a result of research, it was found that the maximum allowable deviations ranged from 34 ‰ to 38 ‰ depending on the number of cars and traction units. The speed of trains with innovative dump trucks on the site is 42 km/h. Key words: dump car, tipping wagon, maximum slope, permissible speed, braking distance, traction unit.

scholarly journals Preliminary assessment of economic effect of transportation in the innovation cars with axial load of 27 tons at the area of the Eastern ground

2020 ◽  
Vol 78 (6) ◽  
pp. 351-357
Author(s):  
O. F. Miroshnichenko ◽  
A. E. Oginskaya
Keyword(s):  
Carrying Capacity ◽  
Axial Load ◽  
Economic Effect ◽  
Economic Assessment ◽  
Preliminary Assessment ◽  
Technical Requirements ◽  
Technical Properties ◽  
Train Length ◽  
The One ◽  
Maintenance Process

The article presents preliminary results of the comprehensive assessment of the economic effect for the infrastructure owner from transportation by trains composed with the innovation freight cars with axial load of 27 tons at the specific areas (grounds). Comprehensive economic assessment for the infrastructure owner consists in taking into account changes of expenses for improvement of technical properties of the new car, as well as the expenses for changes of the operation properties of the car handling areas, in particular: • one-time expenses for putting infrastructure of the areas of cars handling with the axial load from 25 to 27 tons in compliance with the new technical requirements; • financial results due to increase of carrying-capacity by means of increase of the weight at the permanent train length; • change of the current and one-time expenses for train traction composed of the innovation cars of increased carrying-capacity when changing the locomotive series and the number of section-kilometers per the unit of transportation operations.Calculations performed for the routes Chegdomyn – Vanino and Chelutay – Nakhodka indicated that effect of transportation in the innovation cars can be both positive and negative for the infrastructure owner depending on the operation and economic properties of the handling area (volume of transported freight in the examined cars, maintenance process of the locomotive runs, etc.).Taking into account the one-time costs for putting the superstructure in compliance with the technical requirements, the financial results of JSC “RZD” is getting worse at the examined routes.Obtained results have preliminary nature as more detailed accounting of expenses is required for putting infrastructure of the train handling areas composed from the cars of axial load 27 tons in compliance with the technical requirements.

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