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.

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 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.

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.

504 On the Occurrence Conditions of Stick-Slip Phenomena in a Hydraulic Driving System

2000 ◽  
Vol 2000.37 (0) ◽  
pp. 167-168
Author(s):  
Ryo KUMAKURA ◽  
Eisuke TAKANO ◽  
Masato SAEKI
Keyword(s):  
Stick Slip ◽  
Driving System

scholarly journals Rolling at Small Scales

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Kim L. Nielsen ◽  
Christian F. Niordson ◽  
John W. Hutchinson
Keyword(s):  
Strain Gradient ◽  
Scale Effects ◽  
Large Strain ◽  
Power Input ◽  
Rolling Process ◽  
Parameter Study ◽  
Stick Slip ◽  
Roll Torque ◽  
Small Scales ◽  
Gradient Effects

The rolling process is widely used in the metal forming industry and has been so for many years. However, the process has attracted renewed interest as it recently has been adapted to very small scales where conventional plasticity theory cannot accurately predict the material response. It is well-established that gradient effects play a role at the micron scale, and the objective of this study is to demonstrate how strain gradient hardening affects the rolling process. Specifically, the paper addresses how the applied roll torque, roll forces, and the contact conditions are modified by strain gradient plasticity. Metals are known to be stronger when large strain gradients appear over a few microns; hence, the forces involved in the rolling process are expected to increase relatively at these smaller scales. In the present numerical analysis, a steady-state modeling technique that enables convergence without dealing with the transient response period is employed. This allows for a comprehensive parameter study. Coulomb friction, including a stick–slip condition, is used as a first approximation. It is found that length scale effects increase both the forces applied to the roll, the roll torque, and thus the power input to the process. The contact traction is also affected, particularly for sheet thicknesses on the order of 10 μm and below. The influences of the length parameter and the friction coefficient are emphasized, and the results are presented for multiple sheet reductions and roll sizes.

scholarly journals Influence of the Dry Friction Suspension System Characteristics on the Stick-Slip of Vertical Vibration of a Three-Piece Bogie

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Dali Lyu ◽  
Qichang Zhang ◽  
Kewei Lyu ◽  
Jiaxing Liu ◽  
Yulong Li
Keyword(s):  
Numerical Method ◽  
Dry Friction ◽  
Wedge Angle ◽  
Vertical Vibration ◽  
Vibration Damping ◽  
Suspension System ◽  
Railway Vehicle ◽  
Stick Slip ◽  
System Frequency ◽  
Dry Friction Damping

The dry friction structure is a commonly used vibration-damping method for railway vehicles. Insufficient vibration damping performance will cause excessive vibration of the vehicle, which is not conducive to the safety of the vehicle. However, the mechanism of vibration damping and the cause of clamping stagnation have not been well resolved. This paper uses the analytical method, numerical method, and finite element method to analyze the vertical dynamic characteristics of the simple suspension system with dry friction and demonstrates that the numerical method is an effective method to study the dry model. The conditions for the system to produce sticking events were analyzed by the numerical method. The analysis shows that the system's excitation is too small, which causes clamping stagnation to the system. The reduction of the wedge angle and the friction coefficient are conducive to eliminating sticking. A negative side frame angle is conducive to reducing the high-frequency energy of the excitation. Decreasing spring stiffness or increasing system mass to reduce system frequency can reduce sticking events. The mutual verification of different methods confirms the correctness of the analysis method and analyzes the cause of sticking or clamping stagnation from the mechanism, which provides a new idea for the design and improvement of the dry friction damping system of railway vehicle bogies.

About Longitudinal Dynamics of Classical Passenger Trains during Braking Actions

2013 ◽  
Vol 378 ◽  
pp. 74-81 ◽  
Author(s):  
Cătălin Cruceanu ◽  
Camil Ion Crăciun
Keyword(s):  
Traffic Safety ◽  
Numerical Examples ◽  
Longitudinal Dynamics ◽  
Braking System ◽  
Dynamic Forces ◽  
Passenger Trains

There are presented and analyzed specific aspects regarding the main mechanic and pneumatic issues determining the in-train dynamic forces developed during braking actions. Particularities in case of passenger trains are highlighted, with the aim of proving that even in the case of short trains, fitted with UIC type P braking system, longitudinal dynamics can cause significant reactions whose effect cannot be neglected, both in terms of traffic safety and comfort. Numerical examples presented stand for this.

Increasing Hot Rolling Mass of Steel Sheet Products

2016 ◽  
Vol 871 ◽  
pp. 3-8 ◽  
Author(s):  
Viktor Artiukh ◽  
Vladlen Mazur ◽  
Raghu V. Prakash
Keyword(s):  
Hot Rolling ◽  
Steel Sheet ◽  
Rolling Process ◽  
Dynamic Loads ◽  
Dynamic Forces ◽  
Sheet Products ◽  
Technical Solutions ◽  
Metal Delivery

The article exposes contemporary materials and structures for metallurgy. Feasible increase of dynamic forces on the rolling machinery during rolling of billets with masses up to 20 t (Stand No.1 of CWM 1700 HR, «U.S. Steel Košice», Košice, Slovakia, and PJSC «Illich MMPP», Mariupol, Ukraine) is discussed. It is proved that weight of billet, velocities of metal delivery to working rolls and rolling significantly influence the dynamic loads during metal biting. The technical solutions are suggested which would allow the steady rolling process of billets with masses up to 20 t and prevent accidental failures of frame parts, chocks and main lines.

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