scholarly journals The effects of filling characteristics on the longitudinal forces developed in the braking train

2019 ◽  
Vol 290 ◽  
pp. 08005
Author(s):  
Camil Ion Crăciun ◽  
Cătălin Cruceanu
Keyword(s):  
Compressed Air ◽  
Railway Vehicle ◽  
Inertial Forces ◽  
Longitudinal Dynamic ◽  
Dynamic Forces ◽  
Filling Characteristics ◽  
Brake Cylinder ◽  
Global Research

Determination of longitudinal dynamic forces, size assessment as well as their distribution in the train body is, and will be a subject of global research. As observed from the beginning of the evolution of the railway vehicle and the train itself, the main reason for the occurrence of longitudinal dynamic forces is represented by the differences in inertial forces between the consecutive train vehicles. These inertial forces are influenced by the braking forces developed on each vehicle. The brake with which a railway vehicle is equipped is the pneumatic brake with compressed air. It evacuates the air from the train’s general pipeline, increasing the pressure in the brake cylinders of each vehicle. The brake command and cylinder filling is more delayed on long trains compared to short ones. Thus, the brake can operate in two ways, the fast-action brake and the slow-action brake. In this paper, we aim to highlight the influence of the brake type by the brake cylinder filling characteristic of the dynamic longitudinal reactions. It will be analysed on a simplified train model the magnitude and distribution of longitudinal dynamic forces obtained using both braking systems.

scholarly journals Determination of the loads on the rollers of the tubular belt conveyor

2019 ◽  
Vol 109 ◽  
pp. 00096
Author(s):  
Andrii Smirnov ◽  
Tamara Mishchenko
Keyword(s):  
Service Life ◽  
Ritz Method ◽  
Radius Of Curvature ◽  
Inertial Forces ◽  
Belt Conveyor ◽  
Dynamic Forces ◽  
Plates And Shells ◽  
Bulk Load ◽  
Roller Support

The article presents methods for determining loads on rollers of a six-roll support of a tubular belt conveyor, based on the equilibrium laws of elastic cylindrical plates and shells filled with a freight. In this case, the forces acting on the rollers of the tubular conveyor are the sum of the forces caused by the weight and expansion of the bulk load, the weight and bend of the belt, as well as the inertial forces associated with the curvature and the deflection of the belt under the weight of the bulk load. The dynamic forces acting on the rollers as the belt moves are determined from the equation of the oscillations of a heavy flexible string using the Ritz method. As a result of the research, analytical dependences of the forces acting on the rollers of the six-roller support of the tubular conveyor on the parameters of the conveyor, the belt, the properties of the bulk load and the radius of curvature of the conveyor are obtained, and an assessment of the component these forces is given. The results can be used to determine the parameters of the tubular conveyors rollers and increase the service life of the rollers.

Researches on the Behavior of the Supporting Structure of Railway Traction Vehicles under the Effect of Shock Dynamic Forces

2014 ◽  
Vol 659 ◽  
pp. 237-242
Author(s):  
Ioan Sebesan ◽  
Gabriel Popa ◽  
Marius Adrian Spiroiu
Keyword(s):  
Traffic Safety ◽  
Rolling Process ◽  
Railway Vehicle ◽  
Frontal Impact ◽  
Stick Slip ◽  
Driving System ◽  
Supporting Structure ◽  
Longitudinal Dynamic ◽  
Dynamic Forces ◽  
Railway Traction

During circulation the railway vehicle is subjected to the action of dynamic forces under the effect of shocks that appear in the driving system caused by stick slip phenomenon, dynamic forces arising from the rolling process when the wheelset is passing over accidental vertical unevenness of the track and also longitudinal dynamic forces occurring in the case of buffering, respectively those caused by frontal impact (the crash forces). The present paper presents the mechanical and mathematical models which are underlying the evaluation of the magnitude of these forces as well as their effects on the resistance of supporting structure of the vehicle and on traffic safety.

Experimental Determination of Wheel and Guiding Forces on the Tracks

2015 ◽  
Vol 732 ◽  
pp. 203-206
Author(s):  
Lubos Pazdera ◽  
Jaroslav Smutny ◽  
Libor Topolář
Keyword(s):  
Experimental Determination ◽  
Vertical Direction ◽  
Railway Track ◽  
Experimental Basis ◽  
Force Interaction ◽  
Dynamic Forces ◽  
Passing Train ◽  
Strain Measures

Force interaction between a railway track and a vehicle affects the safety, comfort, and last but not least, economical maintenance. Train of wagons incidence on track in both transversal and vertical direction is simplified by qualifying of force wheel (FQ), guiding (FY) and perpendicular and transverse acceleration. An experimental basis for dynamic determination of vertical, FQ, and lateral, FY, forces at the wheel using strain measures in the foot of the rail is given. Measurements of the dynamic forces during passing train are normally very costly and uneasy. These method consists of measuring strains at selected points of the rail profile is very simple and therefore interesting.

scholarly journals Structural vehicle impact loading

2013 ◽  
Vol 11 (3) ◽  
pp. 285-292
Author(s):  
Dragoslav Stojic ◽  
Stefan Conic
Keyword(s):  
Impact Analysis ◽  
Impact Loads ◽  
Structural Elements ◽  
Structural Element ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Vehicle Impact ◽  
Dynamic Forces ◽  
Force Intensity

In contemporary design, vehicle impact into the structures is paid great attention since they can be dominant, depending on the type of structure. The key issue in the vehicle impact analysis is the proper determination of intensity and way of action of dynamic forces on the structural element and its behavior after the imparted load. The Eurocodes, in the annexes provide recommendations for determination of force intensity depending on mass and velocity of the colliding vehicle. Equivalent static loads causing approximate effects on the structural elements are used as quite approximate and efficient methods. The paper comprises the analysis of deformation of columns having the same characteristics, exposed to impact loads via the equivalent static loads, depending on the stress state in columns, and a comparative analysis has been done.

Application of Slender-Body Theory

1957 ◽  
Vol 1 (04) ◽  
pp. 40-49
Author(s):  
Paul Kaplan
Keyword(s):  
Slender Body ◽  
Vertical Force ◽  
Regular Waves ◽  
Slender Body Theory ◽  
Surface Theory ◽  
Surface Ship ◽  
Submerged Body ◽  
Dynamic Forces ◽  
Body Theory

The vertical force and pitching moment acting on a slender submerged body and on a surface ship moving normal to the crests of regular waves are found by application of slender-body theory, which utilizes two-dimensional crossflow concepts. Application of the same techniques also results in the evaluation of the dynamic forces and moments resulting from the heaving and pitching motions of the ship, which corrected previous errors in other works, and agreed with the results of specialized calculations of Havelock and Has-kind. An outline of a rational theory, which unites slender-body theory and linearized free-surface theory, for the determination of the forces, moments and motions of surface ships, is also included.

scholarly journals Methodology for studying impulse disturbance from rail joints to the railway vehicle and assessment of the efficiency of the new spring suspension

2018 ◽  
Vol 239 ◽  
pp. 01032
Author(s):  
Viktor Nekhaev ◽  
Viktor Nikolaev ◽  
Evgenii Cheltygmashev
Keyword(s):  
Energy Dissipation ◽  
Comparative Assessment ◽  
Railway Track ◽  
Railway Vehicle ◽  
Vertical Acceleration ◽  
External Disturbances ◽  
Spring Suspension ◽  
Dynamic Forces ◽  
Typical Scheme ◽  
Freight Car

The methodology for studying the impulse disturbance of the railway track joints on the indicators of the dynamic qualities of the railway vehicle has been developed. The dependence of the impulse repetition factor on the energy dissipation level in the system and the speed of the vehicle is obtained. A comparative assessment of the dynamic qualities of a freight car with a typical scheme of spring suspension and a car with suspension based on the principle of compensation of external disturbances is performed. It has been established that the spring suspension of a freight car based on the principle of compensation of external disturbances delivers to it significantly better indicators of dynamic qualities in comparison with car equipped with a new three-piece truck with a typical scheme of springs. Vertical acceleration of the car’s body with a new scheme of vibration protection and dynamic forces in spring suspension is several times less than for a car with a typical three-piece truck structure.

Effects of Slow-Acting Brakes Application Time Regulated Limits on Freight In-Train Forces

2015 ◽  
Vol 809-810 ◽  
pp. 1133-1138
Author(s):  
Cătălin Cruceanu ◽  
Camil Ion Crăciun
Keyword(s):  
Numerical Simulations ◽  
Air Pressure ◽  
Application Time ◽  
Pressure Data ◽  
Longitudinal Dynamics ◽  
Filling Time ◽  
Tensile Forces ◽  
Filling Characteristics ◽  
Brake Cylinder

The paper originally investigates the influence of the admitted ranges of slow-acting filling time of brake cylinder on longitudinal dynamics of freight trains, using experimental air pressure data obtained in tests on filling characteristics. Mechanical and pneumatic models are summarized and numerical simulations were performed for a train composed of six wagon train, in different filling characteristics configurations. The results reflect significant effects on in-train forces values, while evolution and disposition of compression and tensile forces between neighbored vehicles in the long of the train are also affected.

Submerged Towing Performed by a Monohull Vessel

2011 ◽  
Author(s):  
Tore Jacobsen ◽  
Bernt Leira
Keyword(s):  
Time Integration ◽  
Hydrodynamic Properties ◽  
Limit States ◽  
Drag Forces ◽  
Analysis Methodology ◽  
Marine Structure ◽  
Dynamic Forces ◽  
Analytical Formulas ◽  
Measured Response

During a submerged towing operation of a subsea module, the vessel motions combined with the hydrodynamic properties of the considered module will induce drag forces and dynamic loads on the towing configuration. These loads are important when evaluating different submerged towing concepts and will have implications for structural design with respect to the relevant limit states. However, since it is difficult to quantify the hydrodynamic properties of the towed module, model tests are useful for verifying coefficients which are further used in dynamic analyses of the towing configuration. The objective of this paper is to present an analysis methodology for determination of dynamic forces and hydrodynamic properties of a marine structure during a submerged towing operation. Emphasis is made on a simple analytical model of the dynamic forces based on DNV-RP-H103, and a detailed multibody time integration by means of the MARINTEK computer program SIMO (Simulation of complex marine operations). In order to model the submerged towing operation in SIMO, hydrodynamic properties of the considered towed structure are determined based on analytical formulas presented in DNV-RP-H103. The results from the SIMO model are in addition compared with measured response obtained from an experimental investigation. In general it is found that there is good agreement between experimental and calculated values when the hydrodynamic properties of the components have been identified.

A comparative study of the vibration characteristics of railway vehicle axlebox bearings with inner/outer race faults

2020 ◽  
pp. 095440972097908
Author(s):  
Jinhai Wang ◽  
Jianwei Yang ◽  
Yongliang Bai ◽  
Yue Zhao ◽  
Yuping He ◽  
...  
Keyword(s):  
Longitudinal Vibration ◽  
Research Work ◽  
Vertical Vibration ◽  
Fault Identification ◽  
Railway Vehicle ◽  
Outer Race ◽  
Longitudinal Dynamic ◽  
Healthy State ◽  
Inner Race ◽  
Peak Value

Increasing service time makes the axlebox bearing of railway vehicle vulnerable to develop a fault in inner or outer races, which can cause some serious adverse effects on a railway vehicle’s safe operation. To tackle this problem, we established a railway vehicle vertical-longitudinal dynamic model with inner/outer races faults of axlebox bearing and validated it by experimental data. We utilized the time-synchronous average (TSA) technology to filter the raw signals and studied their vibration features. The results show that the longitudinal vibration features are more sensitive for inner race fault identification, while the vertical vibration features are more suitable for outer race fault identification. For inner race fault identification, the indicator peak-to-peak value (PPV) that increases 1056% relative to the healthy state at the most severe fault performs the best sensitivity. For outer race fault identification, the indicator skewness value (SV) that increases 518% relative to the healthy state at the most severe fault exhibits the best performance. The research work can provide meaningful guidance for accurate diagnosis of axlebox bearing faults of railway vehicles.

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