International Journal of Vehicle Structures and Systems

Rakesh Chandmal Sharma ¹

Affiliations
1 Maharishi Markendeshwar University, Mullana, Ambala, IN

Abstract

This paper details a coupled vertical-lateral 37 degrees of freedom mathematical model of an Indian Railway general sleeper ICF coach is formulated using Lagrangian dynamics. In this analysis, the vertical and lateral irregularities of railway track are incorporated as a random function of time. The simulated results are compared with the experimental data obtained through actual rail vehicle testing. The ride comfort is evaluated incorporating ISO 2631-1 standard.

Keywords

Ride Analysis, Rail Vehicle, Lagrangian Dynamics, Passenger Comfort, Power Spectral Density.

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Rakesh Chandmal Sharma ¹

Affiliations
1 Maharishi Markandeshwar University, Mullana (Ambala), IN

Abstract

In this paper, the state of the art of railway vehicle dynamics is presented. Much of the attention is paid to the performance characteristics such as lateral stability, curving, multibody simulation, wheel to track interaction, ride quality and comfort. The scope and limitations of linear and nonlinear analyses for vehicle dynamics are reviewed. Two and three dimensional theories for wheel-to-track interaction are discussed. Detailed analysis of ride quality and comfort evaluation methods is presented. Some concluding remarks are discussed along with further directions of research in the railway vehicle dynamics.

Keywords

Railway Vehicle Dynamics, Performance Indices, Lateral Stability, Ride Comfort, Creep Forces.

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Rakesh Chandmal Sharma ¹

Affiliations
1 Maharishi Markandeshwar University, Mullana, Ambala, IN

Abstract

In this paper, the ride analysis of Rajdhani coach is undertaken using 37 degrees of freedom vertical-lateral coupled vehicle-track model that is formulated using Lagrangian dynamics. The vehicle is considered to be moving along a straight track at a constant speed of 130 kmph. The simulated results of ride behaviour are compared with the experimental data. A sensitivity analysis is carried out in order to investigate the influence of mass and moment of inertia of car body, suspension stiffness, damping coefficient and wheel base on the ride behaviour.

Keywords

Ride Behaviour, Sensitivity Analysis, Rail Vehicle, Lagrangian Dynamics, Vertical Ride, Lateral Ride.

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Rakesh Chandmal Sharma ¹

Affiliations
1 Maharishi Markandeshwar University, Mullana, Ambala, IN

Abstract

This research paper determines the eigenvalues of main rigid bodies i.e. car body, bolsters, bogie frames and wheel axles of a 37 DoF coupled vertical-lateral model of a General Sleeper ICF coach of Indian Railway formulated using Lagrangian dynamics. The primary and secondary hunting speeds of the railway vehicle are determined to investigate the dynamic stability. Critical parameters which influence the railway vehicle dynamic stability are analysed.

Keywords

Railway Vehicle, Eigenvalue, Dynamic Stability, Hunting Speed, Lagrangian Dynamics.

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Sunil Kumar Sharma ¹, Rakesh Chandmal Sharma ², Anil Kumar ³, Srihari Palli ⁴

Affiliations
1 Centre for Transportation Systems, Indian Institute of Technology, Roorkee, IN
2 Mech. Engg. Dept., Maharishi Markandeshwar University, Mullana, IN
3 Mech. Engg. Dept., Indian Institute of Technology, Roorkee, IN
4 Mech. Engg. Dept., Aditya Institute of Technology and Management, Tekkali, IN

Abstract

Rail vehicle-track modeling and simulations, in past many years is developed a long way from its origins as a research tool. This paper presents an overview of the current features and applications for components of rail vehicle-track dynamic modeling and few challenges which these applications find while doing the simulations. This paper discusses appropriate modeling choices for different applications and analyse the best practice for the optimum performance of suspension components, wheel-rail contact conditions and modeling inputs such as track geometry.

Keywords

Vehicle Dynamics, Modeling and Simulation, Rail Vehicle, Suspension Components, Track Models.

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Srihari Palli ¹, Ramji Koona ², Rakesh Chandmal Sharma ³, Venkatesh Muddada ¹

Affiliations
1 Mech. Engg. Dept., Aditya Institute of Technology and Management, Tekkali, IN
2 Mech. Engg. Dept., Andhra University, College of Engineering, Visakhapatnam, IN
3 Mech. Engg. Dept., Maharishi Markandeshwar University, Mullana, IN

Abstract

Dynamic response of railway coach is a key aspect in the design of coach. Indian railway sleeper and 3 tier AC coaches consist of two railway bogies, where the central distance of the center of gravity between the bogies is 14.9 m. Analysis of railway bogie forms a basis for investigating the behaviour of the coach as a whole. The current work carried out is, vehicle dynamic response in terms of Eigen frequency modal analysis and harmonic analysis of a Indian railway 6 Ton Integral Coach Factory (ICF) bogie using finite element (FE) method. The entire bogie model is discretized using solid92 tetrahedral elements. The primary and secondary suspension systems are modelled as COMBIN14 elements in the FE model of the bogie. Modal analysis of the bogie model using Block Lanczos method in ANSYS is carried out to extract first few natural modes of vibration of the bogie. The roll mode frequency attained in Modal analysis is in good agreement with the fundamental frequency calculated analytically. Sinusoidal excitation is fed as input to bottom wheel points to analyse the harmonic response of the bogie in terms of displacement at different salient locations. Harmonic response results reveal that the bogie left and right locations are more vulnerable than the locations near the centre of gravity of the bogie.

Keywords

Dynamic Response, Modal Analysis, Harmonic Analysis, Finite Element Model, ANSYS.

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Rakesh Chandmal Sharma ¹

Affiliations
1 Mech. Engg. Dept., Maharishi Markandeshwar University, Mullana, IN

Abstract

Ride quality and ride comfort are the most important performance indices of road or rail vehicles and is affected by various factors, such as vibrations, acoustics, smell, temperature, visual stimuli, humidity and seat design. Among these vibration is a dominant factor that influences the performance indices the most. In this work the coupled vertical-lateral mathematical models of Indian rail and road vehicles have been formulated using Lagrangian. The roadway vehicles considered for this analysis are three wheel and light four wheel Indian passenger vehicle. The rail vehicles considered for this analysis are General sleeper ICF coach of Indian railway.

Keywords

Ride Comfort, ISO 2631; Lagrangian Method, Vehicle Model, Frequency Weightings.

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Rakesh Chandmal Sharma ¹

Affiliations
1 Mech. Engg. Dept., Maharishi Markandeshwar University, Mullana, IN

Abstract

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.

Keywords

Ride Comfort, ISO 2631, Weighted RMS Acceleration, Vehicle Model, Frequency Weightings.

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Rakesh Chandmal Sharma ¹, Srihari Palli ², Ramji Koona ³

Affiliations
1 Mech. Engg. Dept., Maharishi Markandeshwar (Deemed to be University) Mullana, IN
2 Mech. Engg. Dept., AITAM, Tekkali, Andhra Pradesh, IN
3 Mech. Engg. Dept., Andhra University College of Engg., Visakhapatnam, Andhra Pradesh, IN

Abstract

In the present work, static and dynamic finite element analyses are carried out on an Indian railway 6 ton RCF sleeper bogie. The geometrical CAD model of railway vehicle has been developed in UG-NX7.5 and has been exported to ANSYS12.1 package where finite element modelling and the required static and dynamic analyses have been performed. For dynamic response, modal, harmonic and transient dynamic analyses are carried out. First few natural modes of vibration of the bogie are extracted in Eigen frequency analysis and it is observed that the roll mode attained at a frequency which is well matched with the fundamental natural frequency calculated analytically. The harmonic peaks obtained are matching well with the natural frequencies obtained in modal analysis. Response to the ground excitation when the bogie passes over a bump is simulated in transient analysis.

Keywords

Railway Bogie, Static Analysis, Transient Analysis, Finite Element Modelling, Laden Sleeper, Unladen Sleeper.

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Rakesh Chandmal Sharma ¹, Srihari Palli ², Sunil Kumar Sharma ³, Mritunjoy Roy ¹

Affiliations
1 Mech. Engg. Dept., Maharishi Markandeshwar (Deemed to be University) Mullana, IN
2 Mech. Engg. Dept., AITAM, Tekkali, Andhra Pradesh, IN
3 Dept. of Mech. Engg, Amity School of Engineering and Technology, Amity University, Uttar Pradesh, Noida, IN

Abstract

Railway sleeper is an important component of railway network. Its clamping is also a critical issue in order to avoid any slippage and to maintain the alignment or cross level. Earlier, railway network used wooden sleepers worldwide. Further steel sleepers in parallel with wooden sleepers have been employed. Both are replaced with concrete sleepers with the advancements. With the modernization, the idea of railway sleepers with fibre composite materials has been introduced which is accepted worldwide due to its unique features over any other type of sleeper. This paper discuss about different composite material sleepers and review the important features associated with them i.e. composition, properties, advantages and limitations.

Keywords

Railway Sleeper, Wooden Sleeper, Steel Sleeper, Concrete Sleeper, Composite Sleeper, FFU Synthetic Sleeper.

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Sunil Kumar Sharma ¹, Rakesh Chandmal Sharma ²

Affiliations
1 Dept. of Mech. Engg, Amity School of Engg. and Tech., Amity University, Uttar Pradesh, Noida, IN
2 Dept. of Mech. Engg.,Maharishi Markandeshwar (Deemed to be University), Mullana, Haryana, IN

Abstract

A semi-active suspension system using Magnetorheological (MR) damper overcomes all the inherent limits of passive and active suspension systems and combines the advantages of both. This paper gives a concise introduction to the suspension system of a passenger vehicle which is presented along with the analysis of semi-active suspension system using MR fluid dampers based on Bingham model. MR dampers are filled with MR fluids whose properties can be controlled by applying voltage signal. To further prove the statement, a quarter car model with two degrees of freedom has been used for modeling the suspension system the sprung mass acceleration of passive suspension system has been compared with the semi-active suspension system using the Bingham model for MRF damper. Simulink/MATLAB is used to carry out the simulation. The results drawn show that the semi-active suspension system performed better than the passive suspension system in terms of vehicle stability.

Keywords

Magnetorheological Damper, Active Suspension, Ride Quality, Bingham Model, Simulink Model.

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Rakesh Chandmal Sharma ¹, Sunil Kumar Sharma ², Srihari Palli ³

Affiliations
1 Mech. Engg. Dept., Maharishi Markandeshwar (Deemed to be University), Mullana, Haryana, IN
2 Dept. of Mech. Engg, Amity School of Engg. and Tech., Amity University, Uttar Pradesh, Noida, IN
3 Mech. Engg. Dept., AITAM, Tekkali, Andra Pradesh, IN

Abstract

Formulation of vehicle dynamics problem is dealt either with Newton’s method or Lagrange’s method. This paper provides a broad understanding of Lagrange’s method applied to railway vehicle system. The Lagrange’s method of analytical dynamics provides a complete set of equations through differentiations of a function called Lagrangian function which includes kinetic and potential energy with respect to independent generalised coordinates assigned to the system. This paper also discusses rigid body rotational dynamics along with the concept of generalised coordinates (constrained and un-constrained) and generalised forces in detail.

Keywords

Lagrangian Function, Euler’s Angle, Newton’s Method, Generalized Forces, Generalized Coordinates, Body Fixed Axes.

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Srihari Palli ¹, Ramji Koona ², Sunil Kumar Sharma ³, Rakesh Chandmal Sharma ⁴

Affiliations
1 Mechanical Engineering Dept., AITAM, Tekkali, Andhra Pradesh, IN
2 Mechanical Engineering Department, Andhra University College of Engineering, Andhra Pradesh, IN
3 Dept. of Mech. Engg, Amity School of Engg. and Tech., Amity University, Uttar Pradesh, Noida, IN
4 Mechanical Engineering Department, Maharishi Markandeshwar (Deemed to be University), Mullana, IN

Abstract

Railway vehicle is one of the rigorously developing passenger and goods carrier in the past few centuries. Dynamic behaviour of the railway coach is a vital aspect in its design and also in terms of passenger safety and ride comfort. Dynamic response includes both deterministic and probabilistic analyses. Modal, harmonic and transient dynamic analysis is part of deterministic analyses, whereas random response using spectrum methods and power spectral density (PSD) is a probabilistic approach. This paper is an attempt to cover various modelling and simulation methods of the railway bogie and coach adopted by various researchers to understand the dynamic behaviour of the railway coach. Further, the research findings of various dynamic parameters obtained theoretically and practically against different inputs like sinusoidal and random inputs to the car body have been discussed. This forms a basis in understanding the development of railway coach design when one is interested in carrying out free and forced vibration analysis on the coach, as well as assists to optimize various design parameters of components like bogie, car body and suspension elements in terms of vehicle dynamics.

Keywords

Railway Coach, Review, Dynamic Analysis, Modelling, Simulation, Wheel-Rail System.

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