Evaluation of Stability in Railway Vehicles on Basis of Bogie Lateral Acceleration

2015 ◽  
Vol 809-810 ◽  
pp. 1031-1036
Author(s):  
Mădălina Dumitriu ◽  
Camil Crăciun
Keyword(s):  
Dynamic Behavior ◽  
Degrees Of Freedom ◽  
Evaluation Method ◽  
Complex Model ◽  
Lateral Acceleration ◽  
Railway Vehicle ◽  
Lateral Direction ◽  
Railway Vehicles ◽  
Secondary Suspension ◽  
The Stability

The paper focuses on evaluating the stability of the railway vehicle during running on a track horizontal irregularities and investigating the possibilities to improve the dynamic behavior on a lateral direction. The evaluation method for the stability relies on the homologation specifications of the railway vehicles from the perspective of the dynamic behavior included in the UIC 518 Leaflet, where the lateral accelerations of the bogies represent evaluation units for the stability. The lateral accelerations are derived from numerical simulations, developed on a non-linear complex model of the vehicle/track system, where the vehicle is described by a mechanical system with 21 degrees of freedom. The results thus presented outline the possibilities of improving the vehicle stability by adopting the best values of the lateral damping of the secondary suspension or of the lateral stiffness of the primary suspension that will lead to the minimizing of the lateral acceleration in a bogie.

scholarly journals Modelling of the Biped Robot with 10 DoF

2017 ◽  
Author(s):  
Ahmet Shala ◽  
Rame Likaj ◽  
Xhevahir Bajrami
Keyword(s):  
Dynamic Behavior ◽  
Degrees Of Freedom ◽  
Biped Robot ◽  
Humanoid Robots ◽  
The Stability

First, a brief overview is provided on humanoid robots, and also models for the dynamic behavior are discussed. As base for these models these two methods Denavit-Hartenberg and Newton-Euler are used. Main aim of this work is to investigate the stability of a biped robot developed from IHRT. There is currently the low base of robot - consisting of feet, legs, hips and upper part of robots body. This structure currently has ten degrees of freedom.

Ride comfort of a higher speed rail vehicle using a magnetorheological suspension system

2017 ◽  
Vol 232 (1) ◽  
pp. 32-48 ◽  
Author(s):  
Sunil Kumar Sharma ◽  
Anil Kumar
Keyword(s):  
Ride Comfort ◽  
Suspension System ◽  
Magnetorheological Damper ◽  
Ride Quality ◽  
Railway Vehicle ◽  
Passive Suspension ◽  
Railway Vehicles ◽  
Rail Vehicle ◽  
Passive Suspension System ◽  
Secondary Suspension

In a railway vehicle, vibrations are generated due to the interaction between wheel and track. To evaluate the effect of vibrations on the ride quality and comfort of a passenger vehicle, the Sperling's ride index method is frequently adopted. This paper focuses on the feasibility of improving the ride quality and comfort of railway vehicles using semiactive secondary suspension based on magnetorheological fluid dampers. Equations of vertical, pitch and roll motions of car body and bogies are developed for an existing rail vehicle. Moreover, nonlinear stiffness and damping functions of passive suspension system are extracted from experimental data. In view of improvement in the ride quality and comfort of the rail vehicle, a magnetorheological damper is integrated in the secondary vertical suspension system. Parameters of the magnetorheological damper depend on current, amplitude and frequency of excitations. Three semi-active suspension strategies with magnetorheological damper are analysed at different running speeds and for periodic track irregularity. The performance indices calculated at different semi-active strategies are juxtaposed with the nonlinear passive suspension system. Simulation results establish that magnetorheological damper strategies in the secondary suspension system of railway vehicles reduce the vertical vibrations to a great extent compared to the existing passive system. Moreover, they lead to improved ride quality and passenger comfort.

Magnetorheological Semi-Active Suspension to Improve High Speed Railway Vehicles Performance

2012 ◽  
Author(s):  
Dan Baiasu ◽  
Gheorghe Ghita ◽  
Ioan Sebesan
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Active Suspension ◽  
Railway Vehicle ◽  
Lateral Dynamics ◽  
Multibody Model ◽  
Logic Control ◽  
Secondary Suspension ◽  
Magneto Rheological ◽  
The Mathematical Model

The paper presents the opportunity of using a magneto-rheological damper to control the lateral oscillations of a passenger railway vehicle to increase its comfort and speed features. The lateral dynamics of the vehicle is simulated using a multibody model with 17 degrees of freedom considering the lateral, yawing and rolling oscillations. The equations describing the model are integrated by the authors using original software. The mathematical model considers the geometrical nonlinearities of the wheel-track contact. The nonlinear stability of the vehicle running on tangent tracks with irregularities is assessed and it is shown the influence of the construction parameters of the suspensions on the vehicle’s performance. A magneto-rheological device with sequential damping based on balance logic control strategy is introduced in the secondary suspension of the vehicle to reduce the lateral accelerations generated by the track’s irregularities. The system’s response in terms of accelerations is compared for both passive and semi-active cases. It is shown that the magneto-rheological semi-active suspension improves the safety and the comfort of the railway vehicle.

Modeling of Railway Vehicles for Virtual Homologation from Dynamic Behavior Perspective

2013 ◽  
Vol 371 ◽  
pp. 647-651 ◽  
Author(s):  
Mădălina Dumitriu
Keyword(s):  
Dynamic Behavior ◽  
Equations Of Motion ◽  
Continuous Model ◽  
Point Of View ◽  
Rolling Stock ◽  
Railway Vehicle ◽  
Analysis Method ◽  
Passenger Car ◽  
Railway Vehicles ◽  
Comfort Index

Modeling and simulation in railway vehicle dynamics is a useful tool in the design of rolling stock when choosing the best solutions for vehicle and infrastructure components in assessing possible risks and, more recently, in the certification of railway vehicles from the point of view of dynamic behavior based on virtual approval. This paper presents the discrete-continuous model of two-level suspension passenger car running along a tangent track with random vertical irregularity as the theoretical tool to asses the parameters of the approval criteria: the running behavior and comfort. The equations of motion are solved in frequency-domain using the modal analysis method and then the carbody acceleration and the comfort index are calculated. The results derived from a numerical simulation performed for the virtual homologation of a particular passenger car are presented, and so is the possibility to improve the design of the vehicle suspension, in compliance with the approval criteria.

On-Line Running Tests for Validating the Numerical Simulations of the Vertical Dynamic Behavior in Railway Vehicles

2014 ◽  
Vol 657 ◽  
pp. 609-613
Author(s):  
Mădălina Dumitriu
Keyword(s):  
Numerical Simulations ◽  
Dynamic Behavior ◽  
Vertical Direction ◽  
The Other ◽  
Railway Vehicle ◽  
Validation Process ◽  
Frequency Spectra ◽  
Railway Vehicles ◽  
Track System ◽  
On Line

The paper focuses on the validation of the numerical simulations regarding the behavior of a railway vehicle while running on a track with irregularities. These simulations are developed from a complex vehicle track system that allows the evaluation of the dynamic behavior on a vertical direction of the railway vehicles in terms of running quality, vibration comfort and the fatigue stress on the track. The validation process consists in the comparison of the acceleration spectra derived from numerical simulations and those from the data recorded during the vehicle circulation on the running line. In this context, the frequency spectra of the measured acceleration are shown that they can be classified into two categories one is of the spectra similar in shape with the ones considered in the numerical simulations, used as a basis for the validation process and the other one includes the acceleration spectra that are sensibly different than the ones derived from the numerical simulations.

Derailment and Dynamic Analysis of Tilting Railway Vehicles Moving Over Irregular Tracks Under Environment Forces

2017 ◽  
Vol 17 (09) ◽  
pp. 1750098 ◽  
Author(s):  
Yung-Chang Cheng ◽  
Chern-Hwa Chen ◽  
Chin-Te Hsu
Keyword(s):  
Degrees Of Freedom ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Railway Vehicles ◽  
Running Safety ◽  
Car Model ◽  
Vertical Roll ◽  
Rail Irregularities ◽  
Creep Models

Utilizing a nonlinear creep model, the dynamic behavior of tilting railway vehicles moving over curved tracks with rail irregularities and under earthquakes and wind loads is studied. The car model adopted consists of 28 degrees of freedom, capable of simulating the lateral, vertical, roll and yaw motions for the wheelsets, truck frames and car body. The derailment quotient is investigated to analyze the running safety of a tilting railway vehicle using the linear and nonlinear creep models, while considering the rail irregularities and environmental forces for various tilting angles. Generally, the derailment risk of the tilting railway vehicle is higher than that of non-tilting railway vehicle with or without rail irregularities and environmental forces. The derailment quotients calculated by the linear creep model are underestimated for a tilting railway vehicle. In addition, the derailment quotients evaluated for rough rails and under environmental forces are higher than those obtained for smooth rails with no environmental forces. It is confirmed that rail irregularities and each type of environmental forces have decisive effects on derailment quotients. They are compared and ranked according to their significance.

Semi-Active Suspension Systems for Railway Vehicles Based on Magnetorheological Fluid Dampers

2007 ◽  
Author(s):  
D. H. Wang ◽  
W. H. Liao
Keyword(s):  
Suspension System ◽  
Full Scale ◽  
Vehicle Suspension ◽  
Railway Vehicle ◽  
Mr Fluid ◽  
Railway Vehicles ◽  
Suspension Systems ◽  
Secondary Suspension ◽  
Fluid Dampers ◽  
Track Irregularities

In this paper, a seventeen degree-of-freedom (DOF) model for a full scale railway vehicle integrated with the semi-active controlled magnetorheological (MR) fluid dampers in its secondary suspension system is proposed to cope with the lateral, yaw, and roll motions of the car body, trucks, and wheelsets. The governing equation considering the dynamics of the railway vehicle integrated with MR fluid dampers in the secondary suspension system and the dynamics of the rail track irregularities are developed. The Linear Quadratic Gaussion (LQG) control law using the acceleration feedback is adopted, in which the state variables are estimated from the measurable accelerations with a Kalman estimator. In order to evaluate how the performances of the railway vehicle system integrated with the semi-active controlled MR fluid dampers can be improved, the lateral, yaw, and roll accelerations of the car body, trucks, and wheelsets of a full scale railway vehicle integrated with MR fluid dampers, which are controlled (the semi-active) and uncontrolled (the passive on and passive off) respectively, are analyzed under the random track irregularities based on the established governing equations and the modelled track irregularities. The simulation results not only show the control effectiveness of the railway vehicle with the semi-active suspension system based on MR fluid dampers for railway vehicles, but also illustrate that the semi-active railway vehicle suspension system based on MR fluid dampers combines the merits of the passive on and passive off railway vehicle suspension systems.

scholarly journals Railway Vehicle Pneumatic Rubber Suspension Modelling and Analysis

2018 ◽  
Vol 55 (1) ◽  
pp. 24-27 ◽  
Author(s):  
Marius Adrian Spiroiu
Keyword(s):  
Dynamic Response ◽  
Railway Vehicle ◽  
Railway Vehicles ◽  
Pneumatic Suspension ◽  
Suspension Stiffness ◽  
Secondary Suspension ◽  
Elastic Elements

The pneumatic elastic elements are widely used in the secondary suspension of modern railway vehicles due to their important advantages compared to the conventional ones. In the present paper, the modelling and analysis of the pneumatic suspension is approached, taking into account the main elements, pneumatic enclosures and rubber elements. The analysis performed investigates the influence of relevant parameters on suspension stiffness and on its dynamic response.

scholarly journals Simulation of Energy Absorption Performance of the Couplers in Urban Railway Vehicles during a Heavy Collision

Machines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 91
Author(s):  
Sunghyun Lim ◽  
Yong-hyeon Ji ◽  
Yeong-il Park
Keyword(s):  
Reaction Force ◽  
Crash Test ◽  
Railway Vehicle ◽  
Buffer System ◽  
Railway Vehicles ◽  
Hydraulic Shock Absorber ◽  
Coupling Buffer ◽  
Absorption Performance ◽  
Different Characteristics ◽  
The Impact

Railway vehicles are generally operated by connecting several vehicles in a row. Mechanisms connecting railway vehicles must also absorb front and rear shock loads that occur during a train’s operation. To minimize damage, rail car couplers are equipped with a buffer system that absorbs the impact of energy. It is difficult to perform a crash test and evaluate performance by applying a buffer to an actual railway vehicle. In this study, a simulation technique using a mathematical buffer model was introduced to overcome these difficulties. For this, a model of each element of the buffer was built based on the experimental data for each element of the coupling buffer system and a collision simulation program was developed. The buffering characteristics of a 10-car train colliding at 25 km/h were analyzed using a developed simulator. The results of the heavy collision simulation showed that the rubber buffer was directly connected to the hydraulic shock absorber in a solid contact state, and displacement of the hydraulic buffer hardly occurred despite the increase in reaction force due to the high impact speed. Since the impact force is concentrated on the vehicle to which the collision is applied, it may be appropriate to apply a deformation tube with different characteristics depending on the vehicle location.

scholarly journals Reliability Estimation of Reinforced Slopes to Prioritize Maintenance Actions

2021 ◽  
Vol 18 (2) ◽  
pp. 373
Author(s):  
Farshad BahooToroody ◽  
Saeed Khalaj ◽  
Leonardo Leoni ◽  
Filippo De Carlo ◽  
Gianpaolo Di Bona ◽  
...  
Keyword(s):  
Urban Areas ◽  
Evaluation Method ◽  
Likelihood Function ◽  
Reliability Estimation ◽  
Analytical Models ◽  
Geotechnical Structures ◽  
Reinforced Slopes ◽  
The Stability ◽  
Methods Analytical ◽  
Asset Managers

Geosynthetics are extensively utilized to improve the stability of geotechnical structures and slopes in urban areas. Among all existing geosynthetics, geotextiles are widely used to reinforce unstable slopes due to their capabilities in facilitating reinforcement and drainage. To reduce settlement and increase the bearing capacity and slope stability, the classical use of geotextiles in embankments has been suggested. However, several catastrophic events have been reported, including failures in slopes in the absence of geotextiles. Many researchers have studied the stability of geotextile-reinforced slopes (GRSs) by employing different methods (analytical models, numerical simulation, etc.). The presence of source-to-source uncertainty in the gathered data increases the complexity of evaluating the failure risk in GRSs since the uncertainty varies among them. Consequently, developing a sound methodology is necessary to alleviate the risk complexity. Our study sought to develop an advanced risk-based maintenance (RBM) methodology for prioritizing maintenance operations by addressing fluctuations that accompany event data. For this purpose, a hierarchical Bayesian approach (HBA) was applied to estimate the failure probabilities of GRSs. Using Markov chain Monte Carlo simulations of likelihood function and prior distribution, the HBA can incorporate the aforementioned uncertainties. The proposed method can be exploited by urban designers, asset managers, and policymakers to predict the mean time to failures, thus directly avoiding unnecessary maintenance and safety consequences. To demonstrate the application of the proposed methodology, the performance of nine reinforced slopes was considered. The results indicate that the average failure probability of the system in an hour is 2.8×10−5 during its lifespan, which shows that the proposed evaluation method is more realistic than the traditional methods.

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