Stress Analysis of Bogie Frame Structure

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Master's Degree Thesis ISRN: BTH-AMT-EX--2017/D15--SE

Supervisors: U. Sridhar, BHEL, India Ansel Berghuvud, BTH

Department of Mechanical Engineering Blekinge Institute of Technology

Karlskrona, Sweden 2017

Chodeshwar Korsa Veera Bhadraiah Dora Bharadwaj

Stress Analysis of Bogie Frame

Structure

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Stress Analysis of Bogie Frame Structure

Chodeshwar Korsa Veera Bhadraiah Dora Bharadwaj

Department of Mechanical Engineering Blekinge Institute of Technology

Karlskrona, Sweden 2017

Thesis submitted for completion of Master of Science in Mechanical Engineering with emphasis on Structural Mechanics at the Department of Mechanical Engineering Blekinge Institute of Technology, Karlskrona, Sweden.

Abstract:

The Bogie frame is an important and integral member of bogie. In Indian Railways, LHB (Linke Hofmann Busch) coaches are used as passenger coaches. They are equipped with FIAT bogie frames. Inorder to overcome the limitations of the existing FIAT bogie frame structure, a new bogie frame structure namely New CASNUB Bogie Frame is designed to equip with LHB coach. The New CASNUB Bogie Frame design is validated by conducting Stress analysis using ANSYS Mechanical APDL software. The stresses induced in both the frame structures are compared. Stresses induced in the New CASNUB Bogie frame are lesser than in the FIAT Bogie frame and are within the allowable stress limits of material used. New CASNUB Bogie Frame can be used as an alternative for LHB coaches in Indian Railways.

Keywords:

LHB Coaches, FIAT Bogie Frame, New CASNUB Bogie Frame, ANSYS Mechanical APDL, Von Mises Stress.

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Acknowledgement

The thesis work is a part of a research project in collaboration between Department of Mechanical Engineering, Blekinge Institute of Technology (BTH), Karlskrona, Sweden and Bharat Heavy Electricals Limited (BHEL), Hyderabad, India.

I would like to thank Dr. Ansel Berghuvud, program director of Mechanical Engineering Department in the master degree program, for his support, suggestion and comments during the thesis work.

I would like to express my gratitude to Mr. U. Sridhar, Addl. General Manager (EMPM), BHEL Corporate R&D, Hyderabad, India for providing information and support during the thesis work. I would like to express gratitude to Dr. P. Prasanna, Assistant Professor, Mechanical Engineering, JNTUHCEH, Hyderabad for the support in my thesis work.

I express my deep sense of gratitude to Mr. J.L.N Rao, AGM, HRM, BHEL, Corporate R&D, Hyderabad for providing permission to work in the reputed organization and necessary help during my thesis.

I am grateful to Mr. S K Padhee, AGM, HRD and Mrs. Vijaya Rani, Raj Bhasha Officer, HRD & ATE, BHEL Corporate R&D for rendering their valuable support.

I would like to express thanks to Mr. Manish Gupta, Mr. V. Subash Reddy, DNM, BHEL Corporate R&D, Hyderabad, India for help in the thesis.

I would also like to thank my friends in India and Sweden for their encouragement and support for the thesis.

I would like to prompt thanks to K.V.S. Alekhya for necessary decision and support during the thesis.

I would like to dedicate my work to my beloved parents K. Jejerambabu &

K. Bhavani, sister Geetha and cousins Venugopal and Lokeshwar for their unconditional love and support.

Karlskrona, October 2017

Chodeshwar Korsa Veera Bhadraiah Dora Bharadwaj

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List of Figures

Figure 2.1 FIAT Bogie 18

Figure 2.2 FIAT Bogie Frame 20

Figure 4.1 CASNUB Bogie 30

Figure 6.1 Keypoints plotted for FIAT frame 35 Figure 6.2 FIAT frame structure after joining volumes 36 Figure 6.3 FIAT frame elements of meshed structure 37 Figure 6.4 Keypoints plotted for new CASNUB frame 38 Figure 6.5 New CASNUB frame structure after joining volumes 39 Figure 6.6 New CASNUB frame elements of meshed structure 40

Figure 7.1 FIAT bogie frame structure 43

Figure 7.2 Plot of Vertical loads applied on Bogie frame 44 Figure 7.3 Plot of Von Mises stress distribution with deformed and

undeformed edge in vertical load case 45

Figure 7.4 Plot of Vertical and transversal loads applied on Bogie

frame 46

Figure 7.5 Plot of Von Mises stress distribution with deformed and undeformed edge in vertical and transversal load case 47 Figure 7.6 Plot of Vertical, transversal and longitudinal loads

applied on Bogie frame 49

Figure 7.7 Plot of Von Mises stress distribution with deformed and undeformed edge in vertical, transversal and longitudinal load case

50

Figure 7.8 Plot of loads applied in potential collision with normal

service load case 51

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8 | P a g e Figure 7.9 Plot of Von Mises stress distribution with deformed and undeformed edge in potential collision with normal service load case

52

Figure 7.10 New CASNUB Bogie frame structure 53 Figure 7.11 Plot of vertical loads applied on Bogie frame 54 Figure 7.12 Plot of Von Mises stress distribution with deformed

and undeformed edge in vertical load case. 55 Figure 7.13 Plot of vertical and transversal loads applied on Bogie

frame 56

Figure 7.14 Plot of Von Mises stress distribution with deformed

and undeformed edge in vertical and transversal load case 57 Figure 7.15 Plot of vertical transversal and longitudinal loads

applied on Bogie frame 58

Figure 7.16 Plot of Von Mises stress distribution with deformed and undeformed edge in vertical transversal and longitudinal load case

60

Figure 7.17 Plot of applied loads in potential collision with normal

service load case 61

Figure 7.18 Plot of Von Mises stress distribution with deformed and undeformed edge in potential collision with normal service load case

62

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List of Tables

Table 2.1 Technical data of FIAT bogie frame 19 Table 4.1 Technical data of CASNUB bogie frame 30 Table 4.2 Forces on FIAT and CASNUB bogie frames 32

Table 7.1 List of Vertical loads 44

Table 7.2 List of Vertical and transversal loads 47 Table 7.3 List of Vertical, transversal and longitudinal loads 48 Table 7.4 List of loads for Collision load case 51

Table 7.5 List of Vertical loads 54

Table 7.6 List of Vertical and transversal loads 56 Table 7.7 List of Vertical, transversal and longitudinal loads 59

Table 7.8 List of loads for Collision load case 61 Table 8.1 Comparison of Maximum Von Mises stresses induced

in FIAT and New CASNUB bogie frame structures 63

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1. Notations

ܥ_ଵ Mass of the driver

ܨ_௑ Longitudinal force on bogie ܨ_௒ Vertical force on bogie ܨ_௓ Transverse force on bogie

݃ Acceleration due to gravity

Kg Kilogram

ܯ_௩ Mass of locomotive in running order

݉݉ Millimetre

݉ ݏΤ ^ଶ Meter per second square

݉^ା Mass of bogie

ܰ Newton

ܰ ݉݉Τ ^ଶ Newton per millimeter square

݊_௔ Number of axles

݊_௕ Number of bogies Ψ Percentage

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Abbreviations

ANSYS Analysis of Systems

APDL ANSYS Parametric Design Language

CASNUB Cast Steel Bogie equipped with Snubber Spring

CS Coordinate System

DOF Degrees of Freedom

EX Young’s Modulus

FE Finite Element

FIAT Fabrica Italina de Automobil Torino FX Force in X direction

FY Force in Y direction FZ Force in Z direction GUI Graphical User Interface ICF Integral Coach Factory

KP Key Point

LHB Linke Hofmann Busch LS Linear Solution

max. Maximum

PRXY Poisson’s Ratio

UIC Union Internationale des Chemins WSP Wheel Slide Protection

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2. Introduction

2.1 Background

Till recently, Indian Railways have been transporting passenger traffic mainly through coaches of ICF design. These types of coaches are having limitations in terms of

x Speed potential.

x Heavy corrosion.

x Poor riding comfort.

x Wearing of parts in the under gear.

To overcome these limitations, Indian Railways started using Linke Hofmann Busch (LHB) coaches as the passenger compartments. These are developed by Linke-Hofmann-Busch of Germany and produced by Rail Coach Factory in Kapurthala, India [1].

Advantages of LHB coaches are x Lighter in weight.

x Run in high speed.

x High passenger capacity.

x Safer due to Centre buffer coupler instead of screw coupling in old design.

x Low corrosion, more life.

x Less maintenance.

x Less noise.

x Energy efficient because of end on generation and improved raiding index.

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2.2 Bogie Description

A railway vehicle is a complex dynamic system with many degrees of freedom. The motion of a railway vehicle is affected by the geometry and resilience of the track, the interaction between wheels and rails, the suspension, and the inertias of component parts.

2.2.1 Bogie Functions

A bogie of a railway vehicle performs a complex set of functions [2]. It must control the wheelsets in the correct alignment to meet the conflicting requirements of stable running on straight track and good curving performance with low track wear. At same time, it must also provide acceptable ride levels in the vehicle to which it is fitted, under a wide range of track conditions

2.2.2 Bogie Components

Bogies are very important in safe railway operations and in performing some functions. The bogies are the undercarriage of the railway vehicle which supports the car body and other necessary parts. In mechanical terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle, thus serving as a modular subassembly of wheels and axles. The bogie has following components [3],

a) Bogie frame b) Bogie transom c) Brake cylinder

d) Primary suspension coil e) Motor suspension tube f) Gearbox

g) Lifting Lug

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14 | P a g e h) Motor

i) Neutral section switch Detector j) Secondary suspension air bag

k) Wheel slide protection system lead to Axlebox l) Loose leads for connection to carbody

m) Shock absorber n) Axlebox cover a) Bogie Frame

The bogie is known as the wagon’s movement system. The bogie frame is either casted or fabricated. The bogie frames are manufactured based on its working conditions. It is the main component which takes the stresses.

b) Bogie Transom

Bogie transom is the transverse structural member of bogie frame (usually two off). It also supports the carbody guidance parts and the traction motors.

c) Brake Cylinder

An air brake cylinder is provided for each wheel. A cylinder can operate tread or disc brakes. Some designs incorporate parking brakes as well. Some bogies have two brake cylinders per wheel for heavy duty braking requirements. Each wheel is provided with a brake disc on each side and a brake pad actuated by the brake cylinder. A pair of pads is hung from the bogie frame and activated by links attached to the piston in the brake cylinder. When air is admitted into the brake cylinder, the internal piston moves these links and causes the brake pads to press against the discs. A brake hanger support bracket carries the brake hangers, from which the pads are hung.

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15 | P a g e d) Primary Suspension Coil

The primary springs connect the Axlebox to the bogie frame. The aim of the bogie springs is to reduce the forces and vibrations, to avoid derailment and to uncouple vibration and noise between the wheelsets and the vehicle body. The primary suspension position is often termed as

“axlebox suspension”. Steel coil springs, two of which are fitted to each axlebox in this design. They carry the weight of the bogie frame and anything attached to it.

e) Motor Suspension Tube

Many motors are suspended between the transverse member of the bogie frame called the transom and the axle. This motor is called "nose suspended" because it is hung between the suspension tube and a single mounting on the bogie transom called the nose.

f) Gearbox

This contains the pinion and gearwheel which connects the drive from the armature to the axle.

g) Lifting Lug

Lifting Lug allows the bogie to be lifted by a crane without the need to tie chains or ropes around the frame.

h) Motor

Normally, each axle has its own motor. It drives the axle through the gearbox. Some designs, particularly on tramcars, use a motor to drive two axles

i) Neutral Section Switch Detector

In the UK, the overhead line is divided into sections with short neutral sections separating them. It is necessary to switch off the current on the train while the neutral section is crossed. A magnetic device mounted on the track marks the start and finish of the neutral section. The device is

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16 | P a g e detected by a box mounted on the leading bogie of the train to inform the equipment when to switch off and on.

j) Secondary Suspension Air Bag

The secondary spring is situated between the bogie frame and the vehicle body. Secondary spring systems of enhanced bogie designs are a combination of air spring bellows and the rubber-metal bearer spring, which supports the system, especially when there is torsional strain and large horizontal excursions. The secondary suspension position may be termed as “central suspension”. Rubber air suspension bags are provided as the secondary suspension system for most modern trains. The air is supplied from the train's compressed air system.

k) Wheel Slide Protection System Lead to Axlebox

Where a Wheel Slide Protection (WSP) system is fitted, axleboxes are fitted with speed sensors. These are connected by means of a cable attached to the WSP box cover on the axle end.

l) Loose Leads for Connection to Car body

The motor circuits are connected to the traction equipment in the car or locomotive by flexible leads shown here.

m) Shock Absorber

The shock absorbers are used to reduce the effects of vibration occurring as a result of the wheel/rail interface.

n) Axlebox Cover

The axlebox is the device that allows the wheelset to rotate by providing the bearing house and also the mountings for the primary suspension to attach the wheelset to the bogie or vehicle frame. The axlebox transmits longitudinal, lateral and vertical forces from the wheelset on to the other bogie elements. From a vehicle dynamic behavior point of view, axleboxes with plain bearings had certain positive features.

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17 | P a g e 2.2.3 Functions of Bogie Frame

Bogie has solid welded bogie frame made up of two longitudinal components connected by two cross beams. The bogie frame is casted or fabricated [4].

x Support railcar body firmly.

x Run stably on both straight and curved track.

x Ensure good ride comfort by absorbing vibration generated by track irregularities and minimizing impact of centrifugal forces when train runs on curves at high speed.

x Minimize generation of tract irregularities and rail abrasion.

x Bogie frame have sections for holding bolster, brake arrangement, axle box guide and many other parts which are welded to the frame.

x The main purpose of the bogie frame is to withstand and/or transfer vertical loads of the superstructure with payload, lateral forces caused due to negotiating the curves and interaction between rail and wheel and longitudinal force due to drafting of the coach by the engine.

x To have flexibility in the wheelbase, two bogies are provided per coach, which are pivoted at two points by members called Centre pivot.

2.3 FIAT Bogie

The FIAT (Fabrica Italina de Automobil Torino) bogie is an adoption of EUROFIMA design. The FIAT bogie belongs to the two-axle type, with a primary and a secondary suspension. Axle guidance is provided by an articulated control arm through a resilient bush. This is a two-stage suspension bogie. The car body directly rests on the secondary stage helical springs, which rests on Y shaped side beam. The bogie frame rests on primary stage

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18 | P a g e helical spring which is resting above the axle box crown. The tracking and braking force from axle to bogie frame is transferred through articulated control arm system of primary suspension.

Hydraulic shock absorbers are used conforming to UIC stipulation.

Figure 2.1 FIAT Bogie 2.3.1 Technical Description of FIAT Bogie

The FIAT Bogie is two-axle type, with a primary and a secondary suspension. The bogie assembly is shown in Figure 2.1. Main Technical features of FIAT Bogie are:

• Solid welded Bogie Frame: The bogie frame is a solid welded frame made by steel sheets and forged or cast parts. The frame is made up of two longitudinal components connected by two cross-beams which also support the brake units. The various supports which connect the different bogie components are welded to the frame as shown in Figure 2.2. The Technical data of FIAT bogie frame are listed in Table 2.1 [5]. The bogie frame rests on the primary suspension spring

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19 | P a g e units and supports the vehicle body by means of a bolster beam. The bolster beam is connected to the bogie frame by the secondary suspension

Table 2.1 Technical Data of FIAT bogie frame

Axle distance 2560 mm

Diameter of new wheels 915 mm

Diameter of max. worn wheel 845 ݉݉

Distance between the wheels 1600 ݉݉

Brake disc diameter 640 ݉݉

Bogie width 3030 ݉݉

Bogie length 3534 ݉݉

Bogie weight 6300 ܭ݃

x Primary suspension: It consist of two steel coil springs (internal/external) laid out on the Control Arm upper part.

x Secondary suspension: It consists of two spring packs which sustain the bolster beam over the bogie frame. Each spring pack is made up by an internal and external spring. An Anti-roll bar fitted on the bogie frame realizes a constant, reduced inclination coefficient during running. The bogie frame is linked to the bolster beam through two vertical dampers, a lateral damper, four safety cables and the traction rods. The bogie frame is linked to the coach body through two yaw dampers.

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20 | P a g e Figure 2.2 FIAT Bogie Frame

x Traction Centre: The traction Centre transmits traction and braking forces between bogie frame and body by a traction lever on the bolster beam pin and two rods.

x Disk Brakes: The FIAT bogie is fitted with pneumatic disk brakes.

The pneumatically operated brake cylinders are fitted with automatic device for taking up the clearances.

x Taper Roller Cartridge Bearing: Fiat Bogie is fitted with 130 mm Cartridge type roller bearings.

2.4 Problem Description

The LHB bogies have FIAT (Fabrica Italina de Automobil Torino) model bogie frame. Though they have several advantages, there is a need for better bogie frame model which suits with LHB coaches.

Concern is to be given to improve the following aspects in the existing FIAT bogie frames,

x The frame should resist high impact forces which may occur during potential collision for the safety of passengers.

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21 | P a g e x The frame should withstand the derailment problems to prevent

the accidents due to track irregularities.

x Reducing the bogie frame weight helps in increased energy efficiency.

2.4 Problem Statement

To Design a new bogie frame structure for LHB coach to overcome limitations of the existing FIAT bogie frame structure. To Validate the design by doing Stress analysis using ANSYS Mechanical APDL software such that the stresses induced in the new designed frame are within the allowable stress limits of material used. Less weighted bogie frame design for increase in energy efficiency.

2.5 Outline of Thesis

Chapter 2 deals with the background of the thesis and description of general Bogie components. The FIAT bogie is described. The thesis is focused on bogie frame, one of the bogie component. In addition, the problem description and problem statement are discussed.

Chapter 3 defines the previous research work related to this thesis. The learnings from each previous research work paper are written as a short description.

Chapter 4 is focused on the force calculations. In this chapter types of forces are explained. The CASNUB bogie frame is described. Forces are calculated for FIAT and New CASNUB Bogie frame.

Chapter 5 shows the methodology used for solving the problem statement.

Chapter 6 deals with the procedure involved during modeling of the FIAT and New CASNUB bogie frames in ANSYS mechanical APDL.

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22 | P a g e Chapter 7 deals with the load cases selected for stress analysis of both the bogie frames. Load applications, stresses induced and analysis of FIAT and New CASNUB bogie frames, plots of von mises stress distributions in each load case are discussed in this chapter.

Chapter 8 deals with the results obtained from the stress analysis of the FIAT and New CASNUB bogie frame structures during different load cases. It includes Discussion about both the bogie frames.

Chapter 9 deals with the conclusions that can be drawn from the analysis and comparison of stresses induced in both the bogie frames.

Chapter 10 gives the future scope for betterment of the New CASNUB bogie frame.

Chapter 11 illustrates the references.

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3. Related Work

Isao Okamoto [2] deals with the different type of bogie configurations and the comparison between them. The bogie elements and their functioning are discussed. The author also explains about the behavior of the bogie under different working conditions.

A.K.S. Ansari [4] deals with comparison between Conventional, Fiat and the Optimized frame. Modelling and analysis is done by using Pro-E and ANSYS. The value of maximum induced stress obtained through analytical method in three cases are little lesser than the value obtained from ANSYS software analysis. The load acting on one side frame is also impacting the other side frame, since there is transfer of load through the cross member.

Yahia Zakaria [7] has focused the work on behavior of the bogie frame by considering two methods, i.e., by using experimental method and by using ANSYS simulations. The author has done a comparative study on the deformation of the bogie frame by obtaining the values from the experimental and simulation method. The extended study about bogie frame strength and its fatigue resistance will be presented. The ANSYS software is used for the simulation of bogie frame.

Nam Po Kim et al. [8] has performed the fatigue strength evaluation for the bogie frame of Korean tilting train. The loading conditions imposed on the bogie frame are calculated. The finite element analysis is used to obtain the stress distribution. The stress concentration occurs at the bended areas crossing the side frame and the cross beams by the finite element analysis.

Syed Yaseen et al. [9] discuss about the load distribution of the casted and fabricated bogie frames. Different load cases are considered for both types of bogie frame and the values are tabulated. The analysis results are shown and compared. The author concludes that the cast design can be replaced with the fabricated bogie design frame, thus reducing the weight and to overcome the manufacturing difficulties.

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24 | P a g e Baciu Florin et al. [10] presents a comparative study regarding the distribution of stresses and strains in a bogie frame. A new opening is designed, Opening III. The experiment is conducted and the values of stress and strain under two conditions, i.e., without and with connections are tabulated. The finite element analysis is done on the frame and the results are studied. The simulation results and the test results are in good agreement, the error being less than 6%. The comparison of the experimental and numerical results showed similar trends and provided reliable information about the behavior of the bogie frame under loading conditions.

Jung-Won Seo et al. [11] discusses to estimate the structural integrity of the bogie frame of an electric car. Strength analysis has been performed by finite element analysis. The static load test, fatigue test and tract test were conducted to evaluate the fatigue strength of bogie frames. The bogie frame has adequate strength against fatigue loads.

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4. Force Calculations

4.1 Forces

During bogie lifetime several external forces, both exceptional and normal service loads, act on the bogie frame, coming from the wheel-rail contact points and from the interfaces with the car body.

These forces are generated from [6]:

x Double sprung masses, including payload.

x Track irregularities.

x Lateral accelerations caused by curve riding.

x Longitudinal accelerations caused by traction and braking.

As well as other typically exceptional events, for instance:

x Exceptional pay-loads.

x Buffer impacts.

x Minor derailments.

Taking into account all the above listed sources the norm defines formulas and coefficients to evaluate the values of the single forces to apply in the calculation process. Groups of these forces, combined in load cases, allow simulating the majority of static and fatigue stress condition on the bogie frame when it is operated on the reference vehicle [7].

4.1.1 Vertical Forces

Vertical forces come from sprung masses. For the typical passenger and locomotive applications, the loads produced by a vertical acceleration of 1.4g on the sprung masses, including the exceptional payload shall be directly applied on the interfaces between bogie frame and secondary suspension. For freight applications different values and application

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26 | P a g e points have to be considered as a consequence of different geometries of frame [8].

ܨ_௒ ൌ ^{ଵǤସ௚ሺெ}^ೡ^ିଶ௠^శ^ሻ

ଶ (4.1) ܨ_௒ - Vertical force on single bogie

ܯ_௩ - mass of locomotive in running order

݉^ା- mass of bogie

݃ - acceleration due to gravity 4.1.2 Transversal Forces

Transversal forces come from each axle. These forces are generated by wheel-rail contact forces in curve riding. The formula takes into consideration the Proud’Homme limit for the sum of the transversal forces and it is the same for all the categories of railway bogies. In the numerical calculations the constraints are normally applied on the axles and the loads on the bogie-car body interface, putting attention to replicate the load scheme of this connection [9].

ܨ_௓ ൌ ʹ ൈ ሺͳͲ^ସ ൅^ሺெ^ೡ^ା஼^భ^ሻ௚

ଷ௡ೌ௡್ ሻ (4.2) ܨ_௓ - Transverse force on bogie

ܯ_௩ - mass of locomotive in running order

݃ - acceleration due to gravity ܥ_ଵ - is the mass of the driver

݊_௔ - is the number of axles

݊_௕ - is the number of bogies

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27 | P a g e 4.1.3 Longitudinal Forces

Longitudinal exceptional forces are caused from Traction and Braking in curve riding [9].

ܨ_௑ ൌ ͲǤͳ ൈ^ெ^ೡ^௚

௡ೌ (4.3) ܨ_௑ - longitudinal force on bogie

ܯ_௩ - mass of locomotive in running order g - acceleration due to gravity

݊_௔ - is the number of axles

4.1.4 Forces of a Potential Collision

The impact forces generate most severe stress state on the longitudinal connection between bogies and car body. This load is caused due to the impact of the car body which induced a longitudinal acceleration of 3g and 5g for locomotives applicable at the center of the gravity of the bogie [9].

ܫ݉݌ܽܿݐ݂݋ݎܿ݁ ൌ ͷ݃ ൈ ܯ_௩ (4.4)

4.2 Force Calculations for FIAT Bogie Frame

The calculations are done according to the information and conditions given as follows,

Mass of locomotive in running order ሺܯ_௩ሻ = 52,500 Kg Mass of bogie ሺ݉^ାሻ = 6300 Kg

Mass of the driver ܥ_ଵ ൌ ͺͷܭ݃

Number of axles ݊_௔ ൌ ʹ

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28 | P a g e Number of bogies ݊_௕ ൌ ʹ

Acceleration due to gravity g = ͻǤͺͳ ݉ ݏΤ ^ଶ Vertical forces calculation

ܨ_௒ ൌͳǤͶ݃ሺܯ_௩െ ʹ݉^ାሻ ʹ

ܨ_௒ ൌͳǤͶሺͻǤͺͳሻሺͷʹͷͲͲ െ ʹሺ͸͵ͲͲሻሻ ʹ

ܨ_௒ ൌ ʹ͹͵ͻͻ͵Ǥ͵ܰ

Transversal forces calculation:

ܨ_௓ ൌ ʹ ൈ ሺͳͲ^ସ൅ሺܯ_௩൅ ܥ_ଵሻ݃

͵݊_௔݊_௕ ሻ

ܨ_௓ ൌ ʹ ൈ ቆͳͲ^ସ൅ሺͷʹͷͲͲ ൅ ͺͷሻ

͵ሺʹሻሺʹሻ ൈ ͻǤͺͳቇ ܨ_௓ ൌ ͳͲͷͻ͹͸ǤͶ͹ͷܰ

Longitudinal forces calculation:

Longitudinal exceptional forces are caused from Traction and Braking in curve riding.

ܨ_௑ ൌ ͲǤͳ ൈܯ_௩݃

݊_௔

ܨ_௑ ൌ ͲǤͳ ൈሺͷʹͷͲͲܺͻǤͺͳሻ ʹ

ܨ_௑ ൌ ʹͷ͹ͷͳǤʹͷܰ

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29 | P a g e Impact force calculation:

This load is caused due to the impact of the car body which induced a acceleration of 5g for locomotives applicable at the center of the gravity of the bogie.

ܫ݉݌ܽܿݐ݂݋ݎܿ݁ ൌ ͷ݃ ൈ ܯ_௩ ܫ݉݌ܽܿݐ݂݋ݎܿ݁ ൌ ʹͷ͹ͷͲͲܰ

4.3 CASNUB Bogie

The CASNUB bogie comprises of two cast steel frames and a floating bolster as shown in Figure 4.1. The bolster is supported on the side frame through two nests of springs. This also provides a friction damping proportional to load. A fabricated mild steel spring plank connects the side frames. The technical data of CASNUB Bogie Frame are listed in Table 4.1[10]. The CASNUB bogie assembly consists of the following components:

x Wheel set with Cartridge Bearing

x Adapter, retainer bolt & side frame key assembly x Side frames with friction plates

x Bolster with wear liners x Spring plank, fit bolts & rivets

x Load bearing springs and snubber springs x Friction shoe wedges

x Centre pivot arrangement comprising of Centre pivot top x Side Bearers

x Bottom, Centre pivot pin, Centre pivot retainer & locking arrangement

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30 | P a g e x Elastomeric Pad

x Bogie Brake Gear x Brake Beam

Figure 4.1 CASNUB Bogie

Table 4.1 Technical Data of CASNUB bogie frame Distance between

journal centres 2260 ݉݉

Diameter of new wheels 1000 ݉݉

Diameter of max. worn wheel 955 ݉݉

Distance between the wheels 2000݉݉

Distance between

side bearers 1474 ݉݉

Bogie weight 5500 ܭ݃

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31 | P a g e

4.4 Force Calculations for CASNUB Bogie Frame

The calculations are done according to the information and conditions given as follows,

Mass of locomotive in running order ሺܯ_௩ሻ = 52,500 Kg Mass of bogie ሺ݉^ାሻ = 6300 Kg

Mass of the driver ܥ_ଵ ൌ ͺͷܭ݃

Number of axles ݊_௔ ൌ ʹ Number of bogies ݊_௕ ൌ ʹ

Acceleration due to gravity g = ͻǤͺͳ ݉ ݏΤ ^ଶ Vertical forces calculation:

ܨ_௒ ൌ ͳǤͶ݃ሺܯ_௩ െ ʹ݉^ାሻ ʹ

ܨ_௒ ൌ ͳǤͶሺͻǤͺͳሻሺͷʹͷͲͲ െ ʹሺͷͷͲͲሻሻ ʹ

ܨ_௒ൌ ʹͺͶͻͺͲǤͷܰ

Transversal forces calculation:

ܨ_௓ൌ ʹ ൈ ሺͳͲ^ସ൅ሺܯ_௩ ൅ ܥ_ଵሻ݃

͵݊_௔݊_௕ ሻ ܨ_௓ ൌ ʹ ൈ ቆͳͲ^ସ ൅ሺͷʹͷͲͲ ൅ ͺͷሻ

͵ሺʹሻሺʹሻ ൈ ͻǤͺͳቇ ܨ_௓ൌ ͳͲͷͻ͹͸ǤͶ͹ͷܰ

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32 | P a g e Longitudinal forces calculation:

ܨ_௑ ൌ ͲǤͳ ൈܯ_௩݃

݊_௔ ܨ_௑ ൌ ͲǤͳ ൈሺͷʹͷͲͲܺͻǤͺͳሻ

ʹ ܨ_௑ ൌ ʹͷ͹ͷͳǤʹͷܰ

Impact force calculation:

This load is caused due to the impact of the car body which induced a acceleration of 5g for locomotives applicable at the center of the gravity of the bogie.

ܫ݉݌ܽܿݐ݂݋ݎܿ݁ ൌ ͷ݃ ൈ ܯ_௩ ܫ݉݌ܽܿݐ݂݋ݎܿ݁ ൌ ʹͷ͹ͷͲͲܰ

The forces on both bogie frames are listed in Table 4.2.

Table 4.2 Forces on FIAT and CASNUB bogie frames

Force Type

Force Magnitude(KN)

FIAT Bogie Frame CASNUB Bogie Frame

Vertical Force 27.4 28.4

Transversal Force 10.6 10.6

Longitudinal force 2.6 2.6

Impact Force 257.5 257.5

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33 | P a g e

5. Methodology

NO

YES

FIAT frame design and modelling in ANSYS Mechanical APDL

Application of loads according to different load cases and stress analysis on FIAT Bogie Frame using ANSYS

New CASNUB frame design and modelling in ANSYS Mechanical APDL

Application of loads according to different load cases and stress analysis on New CASNUB Bogie frame using ANSYS

If Stresses are less than stresses in fiat frame. (and within the Yeild limit)

Optimized New CASNUB Bogie frame is designed for application in Indian Railways

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34 | P a g e

6. Procedure

Two frames namely, FIAT bogie frame and New CASNUB bogie frame are modeled using ANSYS Mechanical APDL software. Same material is selected for both the frames. Loads are applied and stress analysis is done.

6.1 FIAT Bogie Frame

The procedure for modeling and structural analysis of the FIAT bogie frame is as follows [12]:

x Main menu ՜ Preference ՜ Individual discipline(s) to show in the GUI՜ Select Structural՜Discipline options՜h-method ՜ Click

“ok”.

Structural stress analysis is to be done on the Frame structure, hence structural is selected in the GUI [Graphical User Interface].

The h-method improves results by using a finer mesh of the same type of element. This method refers to decreasing the characteristic length (h) of elements, dividing each existing element into two or more elements without changing the type of elements used.

x Main Menu ՜ Preprocessor՜Element type ՜ Add/Edit/Delete ՜ Add ՜ Solid ՜ Brick 8 node 185 ՜Click “ok” ՜ close.

The element is selected as solid and the element type is selected as Brick 8 node 185. The element type has plasticity, hyper elasticity, stress stiffening, creep, large deflection, and large strain capabilities. The element is suitable for modelling general 3-D solid structures, and it also allows better meshing in irregular regions.

x Main Menu ՜ Preprocessor ՜ Material Properties ՜ Material models ՜ Structural ՜ Linear ՜ Elastic ՜ Isotropic ՜ Input young’s Modulus (EX=2E+011) ՜ Input Poison’s Ratio (PRXY=0.29) ՜ Click “ok”.

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35 | P a g e The material properties like elastic, Isotropic, Young’s modulus and Poison’s ratio data are given. The material is steel of grade St 52. Its Young’s Modulus is 2 X 10¹¹

Nmm

^-2

. Poisons ratio is given as 0.29.

x Main Menu ՜ Preprocessor ՜ Modeling ՜ Keypoints ՜ InActive CS ՜ Enter Keypoint number ՜ X, Y, Z location in active CS ՜ Click “Apply” ՜ Enter next Keypoint number ՜ Enter next X, Y, Z location in active CS ՜ Click “Apply” ՜ Click “ok”.

The modelling is done using Keypoints. Enter all the key points required to model the FIAT bogie frame. The Keypoints are entered in the X, Y, Z location in active CS menu. Give numbering to the key points using menu options, then structure appear as shown in Figure 6.1.

Figure 6.1 Key points plotted for FIAT frame

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36 | P a g e Figure 6.2 FIAT frame structure after joining volumes

x Main menu → Preprocessor → Modeling → Create → Volumes → Arbitrary → Through KP’s.

The modelling is done by creating volumes. Volumes are created by joining points according to the design of the structure.

Then the volumes are added into a single unit using Boolean options.

After joining volumes, the structure is as shown in Figure 6.2.

x Main menu ՜ Preprocessor ՜ Meshing ՜ Mesh Tool ՜ “Mesh” ՜ click “Pick All”. [After meshing, it is as shown in Figure 6.6]

The meshing is carried out using the meshing tool. The mesh is done by picking all the volume units to be meshed. Mesh size and type of mesh are selected in the mesh tool for meshing the frame structure After meshing, the frame structure is as shown in Figure 6.3. The nodes appear on the frame structure.

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37 | P a g e Figure 6.3 FIAT frame elements of meshed structure

x Main Menu ՜ Solution ՜ Define Loads ՜ Apply ՜ Structural ՜ Displacement ՜ On nodes ՜ Pick the nodes by mouse click՜ Click

“ok” ՜ Choose “All DOF” and put “0” as the value ՜ Click “ok”.

The structure is to be constrained for analysis. Degrees of freedom are given at nodes and the frame structure is constrained according to the requirements.

x Main Menu ՜ Solution ՜ Define Loads ՜ Apply ՜ Structural ՜ Force/Moment ՜ On nodes ՜ Pick node points ՜ Click “ok”.

The loads are defined on nodes. Nodes are selected and forces are applied in magnitude and direction on each selected node.

x Main Menu ՜ Solution ՜ Solve ՜Current LS ՜ Click “ok” ՜ Click

“yes”.

The solution is solved by using solve menu.

x The results are plotted by using the nodal solution under general post processing menu.

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38 | P a g e

6.2 New CASNUB Bogie Frame

The procedure for modeling and structural analysis of the CASNUB bogie frame is as follows

x Main menu ՜ Preference ՜ Individual discipline(s) to show in the GUI՜ Select Structural՜Discipline options՜h-method ՜ Click

“ok”.

x Main Menu ՜ Preprocessor՜Element type ՜ Add/Edit/Delete ՜ Add ՜ Solid ՜ Brick 8 node 185 ՜Click “ok” ՜ close.

x Main Menu ՜ Preprocessor ՜ Material Props ՜ Material models ՜ Structural ՜ Linear ՜ Elastic ՜ Isotropic ՜ Input young’s Modulus(EX=2E+011) ՜ Input Poison’s Ratio(PRXY=0.29) ՜ Click “ok”.

Figure 6.4 Key points plotted for new CASNUB frame

x Main Menu ՜ Preprocessor ՜ Modeling ՜ Keypoints ՜ InActive CS ՜ Enter Keypoint number ՜ X, Y, Z location in active CS ՜

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39 | P a g e Click “Apply” ՜ Enter next Keypoint number ՜ Enter next X, Y, Z location in active CS ՜ Click “Apply” ՜ Click “ok”. [Enter all the key points required to model the New CASNUB frame. Give numbering to the key points, they appear as shown in Figure 6.4]

x Main menu → Preprocessor → Modeling → Create → Volumes → Arbitrary → Through KP’s [ After joining volumes the structure is as shown in Figure 6.5]

Figure 6.5 New CASNUB frame structure after joining volumes x Main menu ՜ Preprocessor ՜ Meshing ՜ Mesh Tool ՜ “Mesh” ՜

click “Pick All”. [After meshing, it is as shown in Figure 6.6]

x Main Menu ՜ Solution ՜ Define Loads ՜ Apply ՜ Structural ՜ Displacement ՜ On nodes ՜ Pick the nodes by mouse click՜ Click

“ok” ՜ Choose “All DOF” and put “0” as the value ՜ Click “ok”.

x Main Menu ՜ Solution ՜ Define Loads ՜ Apply ՜ Structural ՜ Force/Moment ՜ On nodes ՜ Pick node points ՜ Click “ok”.

x Main Menu ՜ Solution ՜ Solve ՜Current LS ՜ Click “ok” ՜ Click

“yes”.

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40 | P a g e x Main menu ՜ General Post processor ՜ Plot Results ՜ Deformed

shape.

x Main Menu ՜ General Post Processor ՜ Plot Results ՜ Contour Plot

՜ Nodal Solution.

Figure 6.6 New CASNUB frame elements of meshed structure

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41 | P a g e

7. Stress analysis

7.1 Load Cases for Static Stress Analysis

Static stress analysis of a structure is done to make sure that the structure is within the safety limits and to analyze the highly stressed zones in the structure to reduce the chances of failure during its operation [11]. Structure is said to be in safety limits when the ratio between the yield stress of the material and the Maximum stress induced at any point in the whole structure is higher than 1. Higher the value, more is the factor of safety for the structure considered. Four load cases are selected for stress analysis.

x Vertical Load Case

x Vertical and Transversal Loads Case

x Vertical transversal and Longitudinal Loads case x Potential Collision with Normal Service Loads Case 7.1.1 Vertical Load Case

In Vertical load case, Loads acting on the Bogie frame when a Railway vehicle moving in straight path are considered. In this case the passengers load and the on-drive loads are considered. Sometimes exceptional pay loads may act on the bogie frame structure, which are also included in the total vertical load acting on the bogie frame for improved factor of safety to the Bogie frame structure. Points of load application are different for different bogie frame structures. Stress analysis in this load case gives us the normal stresses induced in bogie frame structure during the movement of the vehicle.

7.1.2 Vertical and Transversal Loads Case

In Vertical and Transversal loads case, Loads acting on the Bogie frame when a Railway vehicle moving in curved path are considered. Curve riding causes transversal accelerations, which results in transversal forces causing instability in the railway vehicle. In this case the Bogie frame structure

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42 | P a g e should be able to withstand both the vertical and transversal loads. In this case wheel-rail contact forces, forces due to track irregularities are also considered [12]. Points of load application are different for different bogie frame structures. Stress analysis in this load case gives us the maximum stresses induced in bogie frame structure during the movement of the vehicle in curved path.

7.1.3 Vertical, Transversal and Longitudinal Loads Case

In Vertical, Transversal and Longitudinal loads case, Loads acting on the Bogie frame when a railway vehicle moving in curved path undergoes traction and braking, are considered. Traction and Braking both cause longitudinal acceleration, which results in longitudinal forces acting on the bogie frame structure. Vertical loads, Transversal loads and longitudinal loads are all taken into consideration. Points of load application are different for different bogie frame structures. Stress analysis in this load case gives us the maximum stresses induced in bogie frame structure during the movement of the vehicle in curved path during braking and traction.

7.1.4 Potential Collision with Normal Service Loads Case

In potential Collision with Normal service loads case, Loads acting on the Bogie frame structure when a railway vehicle undergoes potential collision are considered. The severe deformation of the bogie frame structure and the stresses induced can be known in this load case. Failure zones can be predicted.

Actual stresses induced in the bogie frame will be more than the values obtained from analysis of the designed frame structures because:

x The Actual frame consists of slots for fixing the other bogie components.

x Welding of cross beams is done to the side frames, causing stress concentrated zones.

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43 | P a g e

7.2 Stress Analysis of FIAT Bogie Frame

Figure 7.1 FIAT Bogie frame structure in ANSYS

The structure of the FIAT bogie frame modeled in ANSYS Mechanical APDL is as shown in the Figure 7.1. Different set of forces are applied on the frame and static stress analysis is done in all load cases.

7.2.1 Vertical Load Case

In Vertical load case, total vertical load acting on the bogie frame structure is ܨ_௒ ൌ ʹ͹͵ͻͻ͵Ǥ͵ͲͲͲܰ. Total Vertical load acting on frame will be equally distributed onto two side frames. On each side-frame Vertical load of ͳ͵͸ͻͻ͸Ǥ͸ͷͲͲܰ is applied. Load on each side-frame is again equally distributed among two node points, with 68498.3250 N at each node point as

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44 | P a g e shown in Figure 7.2. The Frame is constrained. The vertical loads applied on all four node points are listed in Table 7.1.

Figure 7.2 Plot of Vertical loads applied on Bogie frame Table 7.1 List of Vertical loads

Load location Direction of loading Load Magnitude [N]

Side frame

FY in Negative 68498.3250 FY in Negative 68498.3250

Side frame (other)

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45 | P a g e Figure 7.3 Plot of Von Mises stress distribution with deformed and

undeformed edge in vertical load case

Static stress analysis is done on the frame when vertical loads are applied.

The stresses induced in the frame, the deformation of the frame and von mises stress distribution are shown in the Figure 7.3. Maximum von mises stress induced in the frame is 16.1955 ܰ ݉݉Τ ^ଶ. The allowable stress for the frame is 355 ܰ ݉݉Τ ^ଶ. There is high factor of safety in the structure. Actual stresses are more than the stresses induced in the ANSYS model of the FIAT bogie frame.

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46 | P a g e 7.2.2 Vertical and Transversal Loads Case

In Vertical and Transversal loads case, Total vertical load on the bogie frame is ܨ_௒ ൌ ʹ͹͵ͻͻ͵Ǥ͵ͲͲͲܰ and Total Transversal load on the bogie frame is ܨ_௓ ൌ ͳͲͷͻ͹͸ǤͶ͹ͷͲܰ. Total Vertical load acting on frame will be equally distributed onto two side frames. On each side-frame Vertical load of ͳ͵͸ͻͻ͸Ǥ͸ͷͲͲܰ is applied. Load on each side-frame is again equally distributed among two node points, with 68498.3250 N at each node point.

Total Transversal load of ܨ_௓ ൌ ͳͲͷͻ͹͸ǤͶ͹ͷͲܰ is divided equally on both side-frames. On each Side-frame vertical load of 68498.3250 N acts at two node points and transversal load of 26494.0000 N acts at two other node points as shown in Figure 7.4. The Vertical and Transversal loads applied on all eight node points are listed in Table 7.2.

Figure 7.4 Plot of vertical and transversal loads applied on Bogie frame

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47 | P a g e Table 7.2 List of Vertical and transversal loads

Side frame

FY in Negative 68498.3250 FY in Negative 68498.3250 FZ in Positive 26494.0000 FZ in Positive 26494.0000

Side frame (other)

Figure 7.5 Plot of Von Mises stress distribution with deformed and undeformed edge in vertical and transversal load case

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48 | P a g e Static stress analysis is done on the frame when vertical forces and transversal forces are applied. The stresses induced in the frame, the deformation of the frame and von mises stress distribution are shown in the Figure 7.5. Maximum von mises stress induced in the frame is 43.3781

ܰ ݉݉Τ ^ଶ. The allowable stress for the frame is 355 ܰ ݉݉Τ ^ଶ. There is high factor of safety in the structure. Actual stresses are more than the stresses induced in the ANSYS model of the FIAT bogie frame.

7.2.3 Vertical Transversal and Longitudinal Loads Case

In Vertical, Transversal and Longitudinal loads case, Loads acting on the Bogie frame structure are, Total vertical load of ܨ_௒ ൌ ʹ͹͵ͻͻ͵Ǥ͵ͲͲͲܰ, Total Transversal load of ܨ_௓ൌ ͳͲͷͻ͹͸ǤͶ͹ͷͲܰ and Total Longitudinal load of ܨ_௑ ൌ ʹͷ͹ͷͳǤʹͷͲͲܰ. Vertical load of ͳ͵͸ͻͻ͸Ǥ͸ͷͲͲܰ is applied on each side-frame of the bogie frame structure. Total Transversal load of ܨ_௓ ൌ ͳͲͷͻ͹͸ǤͶ͹ͷͲܰ is divided equally on both side-frames. Total Longitudinal load of ܨ_௑ ൌ ʹͷ͹ͷͳǤʹͷͲͲܰ is divided equally on both side- frames. On each Side-frame vertical load of 68498.3250 N acts at two node points; transversal load of 26494.0000 N acts at two other node points and longitudinal force of 25751.2500 N acts on two other node points as shown in Figure 7.6. The Vertical, Transversal and Longitudinal loads applied on 12 nodes are listed in Table 7.3.

Table 7.3 List of Vertical, transversal and longitudinal loads Load location Direction of loading Load Magnitude [N]

Side frame

FX in Positive 25751.2500 FX in Positive 25751.2500 FY in Negative 68498.3250 FY in Negative 68498.3250 FZ in Positive 26494.0000

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49 | P a g e FZ in Positive 26494.0000

Side frame (other)

FX in Negative 25751.2500 FX in Negative 25751.2500 FY in Negative 68498.3250 FY in Negative 68498.3250 FZ in Positive 26494.0000 FZ in Positive 26494.0000

Figure 7.6 Plot of vertical transversal and longitudinal loads applied on Bogie frame

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50 | P a g e Static stress analysis is done on the frame when vertical forces, transversal forces and longitudinal forces are applied. The stresses induced in the frame, the deformation of the frame and von mises stress distribution are shown in the Figure 7.7. Maximum von mises stress induced in the frame is 43.5118

ܰ ݉݉Τ ^ଶ. The allowable stress for the frame is 355 ܰ ݉݉Τ ^ଶ. There is high factor of safety in the structure. Actual stresses are more than the stresses induced in the ANSYS model of the FIAT bogie frame.

Figure 7.7 Plot of Von Mises stress distribution with deformed and undeformed edge in vertical transversal and longitudinal load case

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51 | P a g e 7.2.4 Potential Collision with Normal Service Load Case

In this load case, Total vertical load on the bogie frame is ܨ_௒ ൌ ʹ͹͵ͻͻ͵Ǥ͵ͲͲͲܰ. Vertical load of ͳ͵͸ͻͻ͸Ǥ͸ͷͲͲܰ is applied on each side- frame of the bogie frame structure. Potential collision load of 2575125.0000 N is applied on the frame. It is divided equally among the two cross beams as shown in Figure 7.8. The applied loads on the Bogie frame structure are listed in Table 7.4.

Figure 7.8 Plot of loads applied in potential collision with normal service load case

Table 7.4 List of loads for Collision load case

Side frame FY in Negative 68498.3250 FY in Negative 68498.3250

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52 | P a g e Side frame (other) FY in Negative 68498.3250

FY in Negative 68498.3250 Cross beam FX in Negative 1287562.00 Cross beam (other) FX in Negative 1287562.00

Figure 7.9 Plot of Von Mises stress distribution with deformed and undeformed edge in potential collision with normal service load case.

Static stress analysis is done on the frame when potential collision force applied along with normal service load. The stresses induced in the frame, the deformation of the frame and von mises stress distribution are shown in the Figure 7.9. Maximum von mises stress induced in the frame is 876.376

ܰ ݉݉Τ ^ଶ. The allowable stress for the frame is 355 ܰ ݉݉Τ ^ଶ. It means the structure fails when potential collision force is applied along with normal service load. There is need for better bogie frame structure to withstand even these forces.

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53 | P a g e

7.3 Stress Analysis of New CASNUB Bogie Frame

Figure 7.10 New CASNUB Bogie frame structure

The structure of the New CASNUB bogie frame modelled in ANSYS Mechanical APDL is as shown in the Figure 7.10. Different set of forces are applied on the frame and static stress analysis is done in all load cases. The maximum stresses induced in the frame are compared with the maximum stresses induced in the FIAT bogie frame.

7.3.1 Vertical Load Case

In Vertical load case, Total vertical load on the bogie frame is ܨ_௒ൌ ʹͺͶͻͺͲǤͷܰ. Vertical load of 284980.5 N is divided equally among two node points with ͳͶʹͶͻͲǤʹͷܰ each and applied on bolster of the Bogie frame

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54 | P a g e structure as shown in Figure 7.11. The Vertical loads applied on two nodes are listed in Table 7.5.

Figure 7.11 Plot of vertical loads applied on Bogie frame Table 7.5 List of Vertical loads

Bolster

Static stress analysis is done on the frame when vertical forces are applied.

The stresses induced in the frame, the deformation of the frame and von mises stress distribution are shown in the Figure 7.12. Maximum von mises stress induced in the frame is 10.9198 ܰ ݉݉Τ ^ଶ. The allowable stress for the

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55 | P a g e frame is 355 ܰ ݉݉Τ ^ଶ. There is high factor of safety in the structure. In Vertical load case, Stresses induced in the New CASNUB bogie frame are lesser than those stresses induced in the FIAT bogie frame and are within the allowable limit of stress.

Figure 7.12 Plot of Von Mises stress distribution with deformed and undeformed edge in vertical load case

7.3.2 Vertical and Transversal Loads Case

In Vertical and Transversal loads case, Total vertical load on the bogie frame is ܨ_௒ൌ ʹͺͶͻͺͲǤͷͲͲͲܰ and Total Transversal load on bogie frame is ܨ_௓ൌ ͳͲͷͻ͹͸ǤͶ͹ͷͲܰ. Vertical load of 284980.5000 N is divided equally among two node points with ͳͶʹͶͻͲǤʹͷͲͲܰ each and applied on bolster of the Bogie frame structure. Similarly, Transversal load of ͳͲͷͻ͹͸ǤͶ͹ͷͲܰ is divided equally among the same node points with 52988.2375 N each as

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56 | P a g e shown in Figure 7.11. The Vertical and Transversal loads applied on two nodes are listed in Table 7.6.

Figure 7.13 Plot of vertical and transversal loads applied on Bogie frame Table 7.6 List of Vertical and transversal loads

Bolster

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undeformed edge in vertical and transversal load case

Static stress analysis is done on the frame when vertical forces and transversal forces are applied. The stresses induced in the frame, the deformation of the frame and von mises stress distribution are shown in the Figure 7.14. Maximum von mises stress induced in the frame is 18.8412

ܰ ݉݉Τ ^ଶ. The allowable stress for the frame is 355 ܰ ݉݉Τ ^ଶ. There is high factor of safety in the structure. Stresses induced in the New CASNUB bogie frame are lesser than those stresses induced in the FIAT bogie frame and are within the allowable limit of stress.

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58 | P a g e 7.3.3 Vertical Transversal and Longitudinal Loads Case

In Vertical, Transversal and Longitudinal loads case, Total vertical load on the bogie frame is ܨ_௒ ൌ ʹͺͶͻͺͲǤͷͲͲͲܰ. Total Transversal load on bogie frame is ܨ_௓ ൌ ͳͲͷͻ͹͸ǤͶ͹ͷͲܰ. Vertical load of 284980.5000 N is divided equally among two node points with ͳͶʹͶͻͲǤʹͷͲͲܰ each and applied on bolster of the Bogie frame structure. Similarly, Transversal load is divided equally among the two node points and applied on the bolster. The Longitudinal load of ʹͷ͹ͷͳǤʹͷͲͲܰ is also applied on the both side-frames on four node points, with two in positive direction and other two in negative direction as shown in Figure 7.15. The Vertical, Transversal and Longitudinal loads applied on six nodes are listed in Table 7.7.

Figure 7.15 Plot of vertical transversal and longitudinal loads applied on Bogie frame

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59 | P a g e Table 7.7 List of Vertical, transversal and longitudinal loads Load location Direction of loading Load Magnitude [N]

Bolster

Side frame

FX in Positive 25751.2500 FX in Positive 25751.2500

Side frame (other)

FX in Negative 25751.2500 FX in Negative 25751.2500

Static stress analysis is done on the frame when vertical forces transversal forces and longitudinal forces are applied. The stresses induced in the frame, the deformation of the frame and von mises stress distribution are shown in the Figure 7.16. Maximum von mises stress induced in the frame is 18.8167

ܰ ݉݉Τ ^ଶ. The allowable stress for the frame is ͵ͷͷܰ ݉݉Τ ^ଶ. There is high factor of safety in the structure. Stresses induced in the New CASNUB bogie frame are lesser than those stresses induced in the FIAT bogie frame and are within the allowable limit of stress.

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undeformed edge in vertical transversal and longitudinal load case

7.3.4 Potential Collision with Normal Service Load Case

In this load case, Total vertical load on the bogie frame is ܨ_௒ ൌ ʹͺͶͻͺͲǤͷͲͲͲܰ. Total Transversal load on bogie frame is ܨ_௓ ൌ ͳͲͷͻ͹͸ǤͶ͹ͷͲܰ. Vertical load of 284980.5000 N is divided equally among two node points with ͳͶʹͶͻͲǤʹͷͲͲܰ each and applied on bolster of the Bogie frame structure. Potential collision load of 2575125.0000 N is applied on the bolster of the frame as shown in Figure 7.17. The applied loads on the Bogie frame structure are listed in Table 7.8.

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61 | P a g e Table 7.8 List of loads for Collision load case

Bolster

FY in Negative 142490.2500 FY in Negative 142490.2500 FX in Negative 2575125.0000

Figure 7.17 Plot of applied loads in potential collision with normal service load case

Static stress analysis is done on the frame when potential collision force applied along with normal service load. The stresses induced in the frame, the deformation of the frame and von mises stress distribution are shown in

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62 | P a g e the Figure 7.18. Maximum von mises stress induced in the frame is 85.6569

ܰ ݉݉Τ ^ଶ. The allowable stress for the frame is 355 ܰ ݉݉Τ ^ଶ. There is high factor of safety in the structure. In this load case, Stresses induced in the New CASNUB bogie frame are lesser than those stresses induced in the FIAT bogie frame and are within the allowable limit of stress. It means the structure is safe when potential collision force is applied along with normal service load.

Figure 7.18 Plot of Von Mises stress distribution with deformed and undeformed edge in potential collision with normal service load case

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63 | P a g e

8. Results and Discussion

Static Stress analysis of two bogie frames namely, FIAT bogie frame and New CASNUB bogie frame is done and maximum Von Mises stress induced in both the structures are listed in Table 8.1.

Table 8.1 Comparison of Maximum Von Mises stresses induced in FIAT and New CASNUB bogie frame structures

Load case (loads applied on the

frame)

Maximum Von Mises Stress Valuesሺࡺ ࢓࢓Τ ^૛ሻ

Percentage of decrease in stresses

induced (%) FIAT bogie

frame

New CASNUB bogie frame

Vertical load case 16.1955 10.9198 32.58 Vertical and

transversal load case 43.3781 18.8412 56.57 Vertical transversal

and longitudinal load case

43.5118 18.8167 56.75

Potential collision with

normal service load 876.376 85.6569 90.23

The results obtained from Stress analysis of both the bogie frames are compared. It is observed that

x In all the Four load cases, maximum Von mises stress induced in the New CASNUB bogie frame structure is less than the maximum Von mises stress induced in FIAT bogie frame structure.

x In Potential collision with normal service load case, Stresses induced in FIAT Bogie frame are very high resulting in the failure FIAT Bogie frame.

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64 | P a g e x New CASNUB bogie frame can withstand high impact forces.

x In Potential collision with normal service load case, there is 90.23 percentage decrease in the stresses induced in New CASNUB bogie frame when compared with the FIAT bogie frame.

New CASNUB bogie frame weights 5500Kg and the FIAT bogie frame weighs 6300 Kg. Decrease in the bogie frame weight helps in reduction of force required to the run the railway vehicle, which indirectly helps in reduction of energy consumption during operation. Thus, New CASNUB bogie frame helps in increased energy efficiency.

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65 | P a g e

9. Conclusion

A New CASNUB Bogie frame structure is designed for LHB coaches to overcome the limitations of the FIAT bogie frame structure. To Validate the design of New CASNUB bogie frame, Static Stress analysis of both the bogie frames is done and maximum Von Mises stresses induced in both the structures are compared. It can be concluded that the New CASNUB bogie frame can be used as a replacement of FIAT bogie frame. The New CASNUB bogie frame suits better for LHB coaches as:

¾ It can resist the high impact forces like collision forces.

¾ The Maximum Stresses induced are lesser than those induced in FIAT bogie frame.

¾ It can resist minor derailment of the wheels.

¾ It can resist stresses induced due to Traction and Braking even in curve riding.

¾ It is lesser in weight than FIAT bogie frame, thus increased energy efficiency.

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10. Future Scope

¾ The CASNUB bogie frame structure can be further improved in Design to suit the requirements of other bogie components.

¾ Improving the wheel and axle design to withstand ware due to high speeds of the railway vehicle.

¾ Improvement of the other bogie components both in efficiency and design to equip with the newly designed CASNUB bogie frame.

Stress Analysis of Bogie Frame Structure

Chodeshwar Korsa Veera Bhadraiah Dora Bharadwaj

Stress Analysis of Bogie Frame

Structure

Stress Analysis of Bogie Frame Structure

Chodeshwar Korsa Veera Bhadraiah Dora Bharadwaj

Department of Mechanical Engineering Blekinge Institute of Technology

Karlskrona, Sweden 2017

Acknowledgement

Contents

List of Figures

List of Tables

1. Notations

Abbreviations

2. Introduction

2.1 Background

2.2 Bogie Description

2.3 FIAT Bogie

2.4 Problem Description

2.4 Problem Statement

2.5 Outline of Thesis

3. Related Work

4. Force Calculations

4.1 Forces

4.2 Force Calculations for FIAT Bogie Frame

4.3 CASNUB Bogie

4.4 Force Calculations for CASNUB Bogie Frame

5. Methodology

6. Procedure

6.1 FIAT Bogie Frame

Nmm

. Poisons ratio is given as 0.29.

6.2 New CASNUB Bogie Frame

7. Stress analysis

7.1 Load Cases for Static Stress Analysis

7.2 Stress Analysis of FIAT Bogie Frame

7.3 Stress Analysis of New CASNUB Bogie Frame

8. Results and Discussion

9. Conclusion

10. Future Scope