Parametric Analysis of the Ride Comfort of Indian Railway Vehicle

2021 ◽  
Vol 13 (4) ◽  
Author(s):  
Rakesh Chandmal Sharma ◽  
Sono Bhardawaj ◽  
Mohd Avesh ◽  
Neeraj Sharma
Keyword(s):  
Mathematical Model ◽  
Parametric Analysis ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Rear Wheel ◽  
Railway Vehicle ◽  
Mass System ◽  
Rail Vehicle ◽  
Indian Railway ◽  
The Mathematical Model

This paper focuses to the parametric analysis of Indian Railway Rajdhani (LHB) coach. A suitable mathematical model of 40 degrees of freedom (DOF) is formulated by Lagrangian method. The mathematical model of rail-vehicle is modelled by considering eleven mass system containing of backseat support (without cushion), a seat, a car body, two (front and Rear) bolsters, two (front and Rear) bogie frame and four wheelaxles (front bogie front and rear wheel axles and rear bogie front and rear wheel axles. The vehicle is simulated to travel at speed of 100 km/hr on a tangent track. The results from the simulation are validated by comparing the same with the results from experimental data which is acquired from research designs and standards organization (RDSO), Lucknow (India). The parametric analysis is performed to estimate the effect of different parameters of rail-vehicle on the ride behaviour.

Analysis of generalized force and its influence on ride and stability of railway vehicle

2020 ◽  
Vol 51 (6) ◽  
pp. 95-109
Author(s):  
Rakesh Chandmal Sharma ◽  
Sakshi Sharma ◽  
Sunil Kumar Sharma ◽  
Neeraj Sharma
Keyword(s):  
Potential Energy ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Contact Point ◽  
Railway Vehicle ◽  
Energy Potential ◽  
Dissipation Energy ◽  
Rail Vehicle ◽  
Random Track Irregularities ◽  
Lagrange’S Method

Formulation of a rail vehicle model using Lagrange’s method requires the system’s kinetic energy, potential energy, spring potential energy, Rayleigh’s dissipation energy and generalized forces to be determined. This article presents a detailed analysis of generalized forces developed at wheel–rail contact point for 27 degrees of freedom–coupled vertical–lateral model of a rail vehicle formulated using Lagrange’s method and subjected to random track irregularities. The vertical–lateral ride comfort of the vehicle and the ride index of the vehicle are evaluated based on ISO 2631-1 comfort specifications and stability is determined using eigenvalue analysis. The parameters that constitute the generalized forces and critically influence ride and stability have been identified and their influences on the same have been analysed in this work.

scholarly journals A numerical and scaled experimental study on ride comfort enhancement of a high-speed rail vehicle through optimizing traction rod stiffness

2020 ◽  
pp. 107754632096192
Author(s):  
Vahid Bokaeian ◽  
Mohammad Ali Rezvani ◽  
Robert Arcos
Keyword(s):  
Rigid Body ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Ride Quality ◽  
Railway Vehicle ◽  
Equivalent Linearization ◽  
Scaled Model ◽  
Rail Vehicle ◽  
Optimal Stiffness

In this research, the effect of rail vehicle carbody’s flexural modes on the ride comfort of an example high-speed railway vehicle is investigated. The vehicle is modeled as a rigid multi-body system, where the rigid body vertical, longitudinal, pitch, and roll degrees of freedom of the carbody and bogie frames and the rigid body vertical and roll degrees of freedom of the wheelsets are considered. An Euler–Bernoulli beam theory is used to account for the flexural motion of the carbody. The longitudinal interaction between carbody and bogie through the traction rod is modeled as a nonlinear spring element. The corresponding equations of motion of the system in the frequency domain are obtained by using the equivalent linearization method. The effect of the traction rod is explored by using this model. Also, the optimal stiffness of the traction rod element that minimizes the flexural vibrations of the carbody is obtained through a genetic algorithm. With the optimal stiffness for the traction rod, the ride quality index at the center of the carbody floor is improved by 41% at a speed of 300 km/h. For the validation of numerical results, a scaled model of the vehicle with a scale factor of 24.5 was constructed, and its associated results are presented. The model was excited by random input signals, which were generated based on the power spectral density of the track irregularity function. The agreement between the simulation results and the scaled experimental outcome when compared with the measured data from other sources is found to be satisfactory. In the framework of the physical scaled model, the filtering effect due to the vehicle bogie base is also examined.

scholarly journals Effect of Rail Vehicle–Track Coupled Dynamics on Fatigue Failure of Coil Spring in a Suspension System

2021 ◽  
Vol 11 (6) ◽  
pp. 2650
Author(s):  
Sunil Kumar Sharma ◽  
Rakesh Chandmal Sharma ◽  
Jaesun Lee
Keyword(s):  
Mathematical Model ◽  
Fatigue Fracture ◽  
Suspension System ◽  
Railway Vehicle ◽  
Coil Spring ◽  
Internal Resonances ◽  
Rail Vehicle ◽  
Rail Vehicles ◽  
Stress Result ◽  
Wheel Track

In a rail vehicle, fatigue fracture causes a significant number of failures in the coil spring of the suspension system. In this work, the origin of these failures is examined by studying the rail wheel–track interaction, the modal analysis of the coil springs and the stresses induced during operation. The spring is tested experimentally, and a mathematical model is developed to show its force vs. displacement characteristics. A vertical 10-degree-of-freedom (DOF) mathematical model of a full-scale railway vehicle is developed, showing the motions of the car body, bogies and wheelsets, which are then combined with a track. The springs show internal resonances at nearly 50–60 Hz, where significant stresses are induced in them. From the stress result, the weakest position in the innerspring is identified and a few guidelines are proposed for the reduction of vibration and stress in rail vehicles.

Development of a reduced dynamic model for comfort evaluation of rail vehicle systems

2016 ◽  
Vol 230 (4) ◽  
pp. 489-504 ◽  
Author(s):  
Mortadha Graa ◽  
Mohamed Nejlaoui ◽  
Ajmi Houidi ◽  
Zouhaier Affi ◽  
Lotfi Romdhane
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Railway Vehicle ◽  
Passenger Comfort ◽  
Rail Vehicle ◽  
Vehicle System ◽  
Comfort Evaluation ◽  
Complex Models ◽  
Reduced Dynamic

In this paper, an analytical reduced dynamic model of a rail vehicle system is developed. This model considers only 38 degrees of freedom of the rail vehicle system. This reduced model can predict the dynamic behaviour of the rail vehicle while being simpler than existing dynamic models. The developed model is validated using experimental results found in the bibliography and its results are compared with existing more complex models from the literature. The developed model is used for the passenger comfort evaluation, which is based on the value of the weighted root mean square acceleration according to the ISO 2631 standard. Several parameters of the system, i.e., passenger position, loading of the railway vehicle and its speed, and their effect on the passenger comfort are investigated. It was shown that the level of comfort is mostly affected by the speed of the railway vehicle and the position of the seat. The load, however, did not have a significant effect on the level of comfort of the passenger.

The Vibration Analysis of Five Degrees of Freedom Man-Vehicle-Road Coupled Model

2013 ◽  
Vol 765-767 ◽  
pp. 361-365
Author(s):  
Pei Cheng Shi ◽  
Wen Chen Xie
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Coupled Model ◽  
Reference Value ◽  
Response Characteristics ◽  
Vibration Model ◽  
Study Results ◽  
Road Surface Roughness ◽  
The Mathematical Model ◽  
The Relationship

The 5-DOF man-vehicle-road coupled vibration model is established by the relationship among three interactions of man-vehicle-road and the vibration differential equation of the 5-DOF man-vehicle-road model is obtained by Newtons method. The mathematical model is conversed into the derived simulation model based on MATLAB/SIMULINK software. The vibration characteristics of the 5-DOF couple model are analyzed by the excitations of ride speed and random road surface roughness time series since the corresponding parameters have been set. The paper demonstrates the acceleration curves and their response characteristics of the bodywork and man-chair system. The study results have a guiding significance and reference value to analyze the vehicle ride comfort.

Engineering Constraint Management Based on an Occurrence Matrix Approach

1993 ◽  
Vol 115 (1) ◽  
pp. 103-109 ◽  
Author(s):  
R. Agrawal ◽  
G. L. Kinzel ◽  
R. Srinivasan ◽  
K. Ishii
Keyword(s):  
Mathematical Model ◽  
Degrees Of Freedom ◽  
Inequality Constraints ◽  
Design Parameters ◽  
Constraint Management ◽  
Management Concepts ◽  
Occurrence Matrix ◽  
Torsion Bar ◽  
The Mathematical Model ◽  
Management Algorithms

In many mechanical systems, the mathematical model can be characterized by m nonlinear equations in n unknowns. The m equations could be either equality constraints or active inequality constraints in a constrained optimization framework. In either case, the mathematical model consists of (n-m) degrees of freedom, and (n-m) unknowns must be specified before the system can be analyzed. In the past, designers have often fixed the set of (n-m) specification variables and computed the remaining n variables using the n equations. This paper presents constraint management algorithms that give the designer complete freedom in the choice of design specifications. An occurrence matrix is used to store relationships among design parameters and constraints, to identify dependencies among the variables, and to help prevent redundant specification. The interactive design of a torsion bar spring is used to illustrate constraint management concepts.

scholarly journals Mathematical Model of Forest Fire Soil-thrower Movement

2020 ◽  
Author(s):  
Olga Dornyak ◽  
Ivan Bartenev ◽  
Mikhail Drapalyuk ◽  
Dmitry Stupnikov ◽  
Sergey Malyukov ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Forest Fire ◽  
Forest Fires ◽  
Degrees Of Freedom ◽  
Translational Motion ◽  
Steady Motion ◽  
Technological Parameters ◽  
Lagrange Equations ◽  
Milling Tool ◽  
The Mathematical Model

The design of a forest fire soil-thrower made to prevent and eliminate ground forest fires is presented. A mathematical model of machine movement has been developed, which enables to study the laws of the interaction process of the design with the soil. It is accepted that the machine has two degrees of freedom. The mathematical model has been obtained using the Lagrange equations of the second kind. The design and technological parameters of the forest fire soil-throwing machine, affecting the efficiency of its work, including mass and width of the grip of the ripper casing, mass, radius and frequency of rotation of the milling tool, the number and geometric parameters of the blades are taken into account. Mathematical model enables to determine the effect of these parameters on the characteristics of the movement of ripper casing and milling working body. A mathematical model is needed to synchronize the translational motion of the unit and the rotational motion of the rotor. Formulas have been obtained for the steady motion of the forest fire soil-thrower, that determine the hauling power of tractor and torque that ensures the operation of milling tools.

scholarly journals A General Modeling Approach for Shock Absorbers: 2 DoF MR Damper Case Study

2021 ◽  
Vol 7 ◽  
Author(s):  
Jorge de-J. Lozoya-Santos ◽  
Juan C. Tudon-Martinez ◽  
Ruben Morales-Menendez ◽  
Olivier Sename ◽  
Andrea Spaggiari ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Degrees Of Freedom ◽  
Linear Models ◽  
Mr Damper ◽  
Shock Absorbers ◽  
Magneto Rheological ◽  
The Mathematical Model ◽  
Force Displacement ◽  
Standard Tests

A methodology is proposed for designing a mathematical model for shock absorbers; the proposal is guided by characteristic diagrams of the shock absorbers. These characteristic diagrams (Force-Displacement, Velocity-Acceleration) are easily constructed from experimental data generated by standard tests. By analyzing the diagrams at different frequencies of interest, they can be classified into one of seven patterns, to guide the design of a model. Finally, the identification of the mathematical model can be obtained using conventional algorithms. This methodology has generated highly non-linear models for 2 degrees of freedom magneto-rheological dampers with high precision (2–10% errors).

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.

Evaluation of Passenger Ride Comfort of Indian Rail and Road Vehicles with ISO 2631-1 Standards Part 2 - Simulation

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
R.C. Sharma
Keyword(s):  
Ride Comfort ◽  
Road Vehicles ◽  
Rail Vehicle ◽  
Normal Duration ◽  
Indian Railway ◽  
Iso 2631 ◽  
Comfortable Ride

In this paper ride comfort of Indian road and rail vehicle is evaluated using ISO 2631-1 comfort specifications. A three wheel vehicle, light four wheel vehicle and general sleeper ICF coach of Indian railway have been evaluated on the basis of 1 hr, 2.5 hrs, 4 hrs and 8 hrs ISO 2631 comfort specifications in seated position as these are the normal duration for passengers. An insight to comfortable ride duration for these vehicles is presented in this paper.

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