Power Axle V6

5/13/2018 Power Axle V6 - slidepdf.com

http://slidepdf.com/reader/full/power-axle-v6 1/48

A Presentation on

Design Validation of Power Axle of a Rail Car by Finite Element Analysis

Department of Mechanical Engineering

DAYANANDA SAGAR COLLEGE OF ENGINEERINGShavige Malleshwara Hills, Kumaraswamy Layout, Bangalore ² 560 078

2011

In partial fulfillment of the requirements for the award of Degree of

Master of Technology in Design EngineeringBy

Gangadhar

USN: 1DS07MDE05

Under the guidance of

Mr. Mahesh G. S. Mr. Kiran M.Assistant Professor Design Engineer

Department of Mechanical Engg., DSCE IMAC Designs Bangalore.



Contents

Introduction

Literature Review

Methods and Methodology Problem Definition and Scope of the work

Results and Discussions

Conclusions and Future work References



Introduction

Rail Vehicles

Types of Rail Vehicles ± Railways

± Subways

± Tramways

Train under test track



Parts of Rail Coach

Standard names used in Rail Coach Bogie Parts



Introduction to Axle

It connects two wheels and givessame rotational speed.

The axle has two bearings at the axle boxes

Wheel axle set is dynamically loadedduring run It is a rotating component of bogie

subjected to heavy loads and fatigueloads

Types of wheel and axle sets ± Power wheel set ± Trailer wheel set ± Trailer wheel with out side brake disc ± Wheel set with three discs mounted

axle

Trailer wheel set



Introduction to Axle (contd.)

Axle Manufacturing ± Axles are manufactured by forging technique through hydraulically operated

arms

± Oxy-acetylene cutter is used to get the required length of rod

± Normalizing, Quenching, Tempering and Ultrasonic testing

Wheel Manufacturing ± Wheels are prepared by sophisticated casting process

± The scrap steel is melted in Ultra high frequency Electric Arc Furnace ± Pouring the molten metal through controlled air pressure system

± Normalizing, Quenching, Tempering and Ultrasonic testing



Accident data base

Sweden maintained a data base of railwayaccidents i.e Derailment

It started from year 1980 to till April 2009 theyfound 35 cases.

Which have been grouped in five categoriesaccording to their primary cause:1. broken rails or other track defects - 16 events

2. axle failure on inside of the wheel - 5 events

3. axle failure on outside of the wheel - 4 events

4. wheel defects - 4 events

5. other causes (impact with objects on track,unidentified causes etc.) - 6 events



Importance of Power Axle Study

Railway axles are subjected to variable amplitude loads

The weight of railway vehicle is introduced through the

bearings During service additional loads like track interaction,

curving, asymmetric loading of axle

Other parameters like torsional axle strains, wheel flats,wheel out of roundness, passenger load spectrum,whether and breaking conditions.



Importance of Power Axle Study (Contd.)

Distribution of Fracture Places in theRailway Traction Shafts and Axles

Typical Fractures of Traction Shafts-Axles in (a) Section1 (b) Section 2 (c) Section 3 (d) Section 4 (e) Section 5



Importance of Power Axle Study (Contd.)

a bc

Different Cracks on (a) Axle in UK (b) Under break seat (c) Close to wheel Seat

a b

Cracks in Axle Centre (a) Radial Cracks (b) Volume Defect



Literature Review

Tests to detect cracks at carriage axles and to evaluate the quality of axles surfaced

The periodicity for testing using probabilistic fracture mechanics

Traction of shafts and axle of railway vehicles under accidental andunpredictable conditions

Fatigue study of railway axles

The effects of corrosion on fatigue properties

Rotary bending and press fitting on stress intensity factor and crack

growth Crack propagation under rolling contact between wheel and track

Thermal and stress analysis of brake discs in railway vehicles



Methods and Methodology

Introduction to FEM

Features of FEM

Basic steps involved in FEM

± Geometrical modeling ± Discretization

± Formulation of elemental equations

± Derivation of elemental properties

± Assembly of equations

± Boundary conditions

± Computation of strain

± Computation of stress



Introduction to ANSYS

Evolution of ANSYS

Features of ANSYS

ANSYS modeling

Importing solid models from CAD systems

Mesh generation

Solving the problem

Reviewing the Results



Problem Definition

Introduction

The objective of the problem

Methodology

Power axle CAD model Power axle with mounted members



Material Properties

Property For Axle structure For Wheel structure

Material A4T Cast Steel

Young's modulus 200 GPa 200 GPa

Poisson's ratio 0.3 0.3

Density 7850 kg/m3 7833 kg/m3

Specific Heat 427 J/kg 0 C 465 J/kg 0 C

Thermal Conductivity 42W/m 0 C 42W/m 0 C

Allowable Stress 145 MPa --Thermal expansion coefficient -- 10.5e-6/ 0 C

Convection film coefficient -- 22.7 W/m2 0 C



Stress and Moment Calculations

Section of axle considered for calculations



Representation of Forces and Formulae's

For all axles defined in thescope of this standard

P1 = (0.625 + 0.0875 h1 / b) m1 g

P2 = (0.625 - 0.0875 h1 / b) m1 g

Y1 = 0.35 m1 g

Y2 = 0.175 m1 g

H = Y1 ± Y2 = 0.175 m1 g

Q1 = [ P1 (b + s) ± P2 (b ±s) + (Y1 ±Y2) R ± Fi (2s ± yi )]

Q2 = [ P2 (b + s) ± P1 (b ±s) - (Y1 ±Y2) R ± Fi yi ]

Formulae¶s Used for Theoretical Calculations as Per EN 13104



Moment Calculations and Design inputs

Sl No Symbol Quantity Sl No Symbol Quantity

1 M1 7500 kg 9 Y0 250 mm

2 M1+M2 8500 kg 10 rb 210 mm

3 F1 4.41 kN 11 s 750 mm

4 H1 1040 mm 12 P=P¶ 41.69 kN

5 B 1000 mm 13 Brake Disc mass 200 Kg

6 g 9.81m/sec2 14 F1 4410 N

7 R 410 mm 15 Y1 1295 mm

8 R b 210 mm 16 Fi 55000 N

Design Input Values



Sectional Moment and Stress calculations

At section 1

± y=0

± Moment Mx = P1 y=52700*0=0

At Section 2

± y=250 mm ± Mx= 23.7 kN

± M¶x = 1.232 kN-m

± M¶y= 5.128 kN-m

± M¶z=1.232 kN-m

±

MR =sqrt ((23.7 + 3.609)2

+ 5.1282

+ 1.2322

) = 27.8 kN-m ± Stress =1*32*27800/ (*.1583) = 72 MPa

± =1*32*23700/ (*.1583) = 61.3 MPa (without braking)



Sectional Moment and Stress calculations (contd.)

At Section 3

± y=615 mm

± d=130 mm

± D=210 mm

± r=75 mm ± K=1.02

± Mx= 21.8 kN

± M¶x = 6.7 kN-m

± M¶y= 5.128 kN-m

±

M¶z=1.232 kN-m ± MR = 29 kN-m

± Stress = 137 MPa

± =105 MPa (without braking)



Sectional Moment and Stress calculations (contd.)

At Section 4

± y=1000 mm

± K = 1

± d = 130 mm (0.13 m)

± Mx= 19.87 kN ± M¶x = 4.81 kN-m

± M¶y= 5.128 kN-m

± M¶z=1.232 kN-m

± MR = 25.24 kN-m

±

Stress = 117.3 MPa ± =93.7 MPa (without braking)



FEM Representation

Geometry Model with Built Up Geometry

Element Representation of the Shaft with Axle



FEM Representation (Contd.)

Bending Moment Diagr am for the Given Loading

Figure shows bending moment for the given load of power axle. The maximum bendingmoment value is around 23.8 kN-m which is exactly matching with theoreticallycalculated value of 23.7 kN-m




Bending Stress Diagram for the Loads

The bending stress diagram represents only half of the axle. The bendingStress at section 1 is zero which is matching with the theoretical calculations




Bending Stress at Section 2

The stress value is around 61.523 MPa which is very near to theoretically calculatedvalue of 62.3 MPa





The value is around 103.622 MPa which is calculated without considering the stressconcentration factor. If stress concentration factor is used for calculation, the stress valueequal to 1.02*103.622=105.69 MPa which is very close to the theoretical value of 105 MPa.





The maximum stress value equals to 94.815 MPa which is near to the theoretical value of 93.7 Mpa

So FEM values are matching with theoretically obtained values.




Maximum Stress in the Structure

Stress developed is only 42.461 MPa which is less than the allowable value of 145MPa for the given material

Starting Conditions



FEM Representation (Contd.)Braking Conditions

Stress with One Brake Disc

Figure shows failure of shaft as the stress 156.479 MPa exceeds the allowable stresslimit 145 MPa of the problem



FEM Representation (Contd.)Braking Conditions

Stress on Axle with two break disc

Figure shows the safety of the axle with two symmetric brake discs as the stressdeveloped is within the allowable range of the material which is 126.71 MPa



Results and Discussion

Initially the axle is checked for self weight condition

And next axisymmetry approach of problem is checked for rotation, interference and thermal conditions

3DMesh of the Solid Axle



Results for self weight condition

Deflection Due to Self Weight

Maximum deflection due to self weight is around 0.00268mm taking place at thecenter

The three dimensional has built and simply supported condition is given at wheel position



Results for self weight condition

von Mises Stress Plot

Maximum von Mises stress is around 0.659035 MPa due to self weight of the problem

Maximum stress are taking place in the middle wheel position and brake pad position



Axisymmetric Analysis

Section Extracted from the Axle Model

(Half Model)

Axisymmetric Map Mesh of Axle

The problem is analysed for 600 rpm rotational load considering 100KMPH maximumspeed

Area is extracted along the axis and map meshed using 4 noded plane42 elements

The geometry is divided to ease the map mesh of the problem

More divisions are considered across sharp geometrical variation regions



Rotational loads

Deformation Under Rotational Load Radial Stress Distribution Under Rotational Load

Almost negligible deformation of around 0.00571mm is taking place in thestructure

Maximum 7.68 MPa stress is taking place due to rotational load of 600 rpm of theaxle



Rotational loads (Contd)

Hoop Stress Plot of Wheel von Mises Stress Plot of the Wheel

Maximum Hoop stress is around 4.62 MPa stress taking place in the structure

Maximum von Mises stress is around 5.72 MPa is taking place in the structure



Rotational loads (Contd)

Radial, Hoop and von Mises Stress Variationvon Mises Stress in the Axle

Maximum von Mises stress is around 1.7MPa at the middle of the axle

Wheel mounting position the stress variation for radial, hoop and von Misesstresses are represented. Here stresses are observed maximum at the web

position and negligible at the axle position



Interference Analysis

Radial Stress Distribution of Wheel Hoop Stress Distribution of Wheel

Maximum compressive stress is around 34.227 MPa and maximum tensile stressof around 0.250181 MPa is taking place on the combined structure

Maximum hoop stress is around 53.185 MPa on the wheel structure and 35.255MPa of compressive stress on inner axle structure



Interference Analysis (Contd.)

von Mises Stress Distribution in the Wheel von Mises Stress in the Shaft Due to

Contact Pressure

von Mises stress of around 67.689 MPa on the interface region of wheel and axle. Inthe problem an interference of 25microns is applied to increase load carrying capacity

Maximum von Mises stress is around 33.808 MPa taking place at the axis due tocontact pressure



Thermal Analysis

Temperature Plot During Braking on the Wheel

Maximum temperature developed is around 174.8 0 C. This temperature is mainly onthe wheel face and almost room temperature can be observed across the wheel axle



Thermal Analysis (Contd.)

von Mises Stress Due to the Thermal Loading von Mises Stress on the Axle Due to

Temperature Load

Maximum stress is around 47.4 MPa due to temperature load can be observed

von Mises stress in the structure. Maximum von Mises stress is around 27.5 MPaon the center of axle



Modal Analysis

Set No Frequency(Hz)

1 487.56

2 487.72

3 1167.5

4 1168.1

5 1365.9

Modal Frequencies

Mode Shape for the I st Modal Frequency

Modal nature of the shaft. Maximum displacement in the member is around0.14788m taking place at the centre showing lateral vibration

Since this frequency is higher than the operational frequency of 10Hzcorresponding to 600 rpm



Summary of LoadsDescription von Mises Stress (MPa)

Maximum stress at the centre under normal

running conditions

103.622

Static Torque conditions 42.461

Braking condition with single brake disc 156.429Braking condition with two brake disc

arranged symmetrically

126.171

Self weight 0.659

Rotation 1.7

Interference 33.08

Thermal loads 27.5



Conclusions

Initially a free body diagram is represented for the power axle based on loadscoming on the structure during operation

Theoretical calculations are calculated for the loads

Totally 4 sections are considered for theoretical moment and stress calculations

Further Finite Element verification is carried out to check the stress condition

The axial model is built using CATIA software for the specified dimensions

Further analyses carried out with rotational load corresponding to 100KMPh

Interference effect is studied on the problem. The interference load of 25 microns isapplied

Transient thermal analysis is carried out to check the thermal effects on the axle

during braking The modal analysis results for axle shows, first natural frequency of 486Hz which

is very high compared to the operational frequency of 10Hz

All the results shows, a combination of these loads are by law of superposition alsoare within the allowable working stress of the material



Further Scope

The analysis can be extended for harmonic loads which will come across junction of rails.

The structure can be optimized with reference to weight and for stressconcentration at the flange region.

The shape of the wheel can be further optimized to reduce thermal effects The structure can be tested composites for better strength to weight ratio

and possible reduction of heat effects

Any possible residual stress effects can be explored.

Seismic effects on wheel and rail also can be explored.

Rail curvature effects can be considered. Rail surface irregularities effect also can be considered

Wear out wheel surface imperfections also can be studied for functionalsafety of the axle.



References1. A.S. Watson, K. Timmis , ³A Method Of Estimating Railway Axle Stress Spectra´ Engineering Fracture Mechanics, 2010.

2. M. Ognjanovic, A. Simonovic, M. Ristivojevic, T. Lazovic, ³Research of Rail Traction Shafts and Axles Fractures TowardsImpact of Service Conditions and Fatigue Damage Accumulation´, Engineering Failure Analysis 17 (2010) 1560±1571

3. Viktor Jemec, Joe Jurman & Janez Grum, ³Evaluation of Defects and Cracks In Carriage Axles Using Non-DestructiveTesting´, Ndt For Safety November 07±09, 2007, Prague, Czech Republic

4. J Rudlin, A Muhammed and C Schneider, ³Inspection Reliability and Periodicity For Rail Axle Inspection , Rail AxleInspection

5. S. Beretta , A. Ghidini, F. Lombardo, ³Fracture Mechanics and Scale Effects In The Fatigue of Railway Axles´, EngineeringFracture Mechanics 72 (2005) 195±208

6. S. Beretta, M. Carboni, G. Fiore, A. Lo Conte, ³Corrosion±Fatigue of A1n Railway Axle Steel Exposed to Rainwater´,

International Journal of Fatigue 32 (2010) 952±961

7. M. Madia a, S. Beretta, U. Zerbst, ³An Investigation On The Influence of Rotary Bending and Press Fitting On StressIntensity Factors and Fatigue Crack Growth In Railway Axles´, Engineering Fracture Mechanics 75 (2008) 1906±1920

8. M. Luke, I. Varfolomeev a, K. Lütkepohl, A. Esderts, ³Fatigue Crack Growth In Railway Axles: Assessment Concept AndValidation Tests´, Engineering Fracture Mechanics (2010)



References (Contd.)9. Yongming Liu, Liming Liu, Sankaran Mahadevan, ³Analysis Of Subsurface Crack Propagation Under Rolling Contact

Loading In Railroad Wheels Using FEM´, Engineering Fracture Mechanics 74 (2007) 2659±2674

10. Reibenschuh, M.; Lerher, T.; raml, M.; amec, B.; Potrè, I, ³Thermal and Stress Analysis of Brake Discs In RailwayVehicles´, Advanced Engineering 3(2009)1, Issn 1846-5900

11. Aar Manual Of Standards and Recommended Practices Wheels and Axles,S-600, 1981railway Applications ± Wheelsets And

Bogies, Powered Axles ± Design Method, English Version Of Din En 13104,Feb, 2002

12. University Of Cambridge, Department Of Engineering, ³Dynamics And Vibrations´, Annual Report-1996\1997.

13. Norton, Robert L., Machine Design ± An Integrated Approach, Prentice-Hall: New Jersey, 1998, 2 nd printing

14. Kelley,´ Fundamentals Of Mechanical Vibration´, Tata- McGraw Hill Publishing Company Limited, 2000.

15. Groover,´ Mechanical Vibration´, New Chand & Bros, 2000.

16. Klaus-Jurgen Bathe ³Finite Element Procedures , Prentice Hall of India Pvt. Ltd.- Sixth Edition 2002

17. Introuduction to the Finite Element Method, Desai/Abel ± CBS publishers 200218. Rober D. Cook, David S ³Concepts and Application of Finite Element Analysis´ Joh Wiely & Sons Pte. Ltd. Fourth

Edition 2003

19. Tirupathi R. Chandrupatla, Ashok D. Belegundu, ³Finite Elements in Engineering Prentice- Hall of India Pvt. Ltd, 2003

20. User Guide, ANSYS 10.0, Reference Mannual, 2010



THANK YOU

Documents

Power Axle V6