Dynamic Contact Analysis of Wheel and Rail Mechanism for Obtaining Maximum Contact Pressure

Dynamic Contact Analysis of Wheel and Rail Mechanism for Obtaining Maximum Contact Pressure

M. V. Sowndarya PG Student

Mechanical Department

Vnr Vignana Jyothi Institute of Engineering and Technology ,

Hyderabad, India

V. Ratna Kiran Assistant Professor

Mechanical Department

Vnr Vignana Jyothi Institute of Engineering and Technology

Hyderabad, India

Abstract: Railway transportation system, as one of the notable means of commuting systems serves for the human societies. The wheelrail contact is a crucial component in the successful operation of railways. The stress distribution is an important factor at the Rail- Wheel contact interfaces, that is, two materials contacting at rolling interfaces which are extremely influenced by geometry of the contacting surfaces, material attributes and loading and boundary conditions. The rolling contact of a wheel on a rail is the basis of many Rail-Wheel related problems which include wear, plastic deformation, fatigue etc. Using CATIA, wheel and rail are modelled individually and assembled. The finite element analysis i.e ANSYS is used to perform the contact analysis by considering the loading and boundary conditions of the rail and wheel contact for a stress analysis. A 3-D finite element model of wheel and rail rolling contact is developed on the most critical section of rail track to analyse the maximum contact pressure using the phenomena of surface contact analysis module. The model generated should be accurately calculating the 3D stress response at the contact region of wheel – rail.

Keywords :: Wheel Rail Contact, CATIA, ANSYS

1. INTRODUCTION

   Railway transportation system, as one of the notable means of commuting systems, has served for human societies and has pursued its improvements as other promoted aspects of life. The track or Permanent Way is the rail-road on which trains run. The track or Permanent Way is the rail-road on which trains run. It basically consists of parallel rails having a specified distance in between and fastened to sleepers, which are embedded in a layer of ballast of specified thickness spread over the formation. The rolling contact of a wheel on a rail is the basis of many Rail-Wheel related problems including the rail corrugation, wear, plastic deformation, rotating interaction fatigue, thermo-elastic- plastic behaviour in contact, fracture, creep, and vehicle dynamics Vibration. Therefore, it has attracted a lot of researchers to various railway networks. The stress distribution is an important factor at the Rail- Wheel contact interfaces, that is, two materials contacting at rolling interfaces which are extremely influenced by geometry of

   the contacting surfaces material attributes, and loading and boundary conditions.

   The contribution of this project is to establish a FEM model of rail and wheel interaction in order to evaluate the stresses, strains and the contact forces by considering the real condition of wheel and rail including boundary and loading conditions.

   Fig 1 : Assembly of wheel and rail.

2. CREATION OF THE MODEL

   In CATIA V5, the components wheel and rail are modelled individually and assembled in order to obtain the complete model. The required data for the rail are obtained from [1].The slope of the rail in international railways can be either 1 : 20 or 1 : 40. The standard UIC 60 profile is considered for the interaction of contact forces and 1800mm is considered as the length of the rail. The standard wheel profile of 920mm diameter is considered for the modelling of the wheel[2].

   Fig 2: CATIA model of wheel and rail assembly

   A. MATERIAL PROPERTIES Youngs modulus 210Gpa Material density 7820kg/m3 Yield strength 500Mpa

   Ultimate tensile strength 880Mpa Tensile yield strength 540Mpa Compressive yield strength 540Mpa

3. ANALYSIS

   Fem is the process of breaking a complex structure into smaller parts to gain a better understanding of it. The model is divided into finite number of elements and analysed in order to view the displacement, stress, and thermal distribution plot etc. A 3-D finite element model for element model for wheel/rail rolling contact is developed on the most critical section of the railway track.

   A 3D CAD model is imported in IGES format in ANSYS [4]. .The contact region is established to the imported model by selecting the interacting regions of wheel and rail. A Bonded contact is established between the two regions by selecting the interacting surfaces of wheel and rail. The meshing is performed by to the model with 49614 nodes and the 21263 elements.

   Fig 3: contact region of the wheel and rail

   Fig 4: Bonded contact of the wheel and rail

   Fig 5: Meshing

   Now considering the boundary conditions of wheel and rail a static structural analysis is performed to the model.

   The two ends of the rail is fixed las they are joined by the rivets and the centre of the wheel where the axle is placed fixed as the rotation of the wheel is not considered for static structural analysis. And the quasi static load of 200KN[3] is applied on the wheel in order to calculate the stress and strain. After applying all the boundary conditions on the model the solution is solved and the results are evaluated.

   Fig 6: Fixed supports

   Fig7 : Force of 200KN

   TRANSIENT STRUCTURAL ANALYSIS

   The transient structural analysis is performed at varying time loads by applying the boundary conditions of static structural analysis. In this analysis the stresses at time interval t = 0, t = 0.25, t = 0.5, t = 0.75, t = 1 are evaluated and the contact status and pressure are analysed.

4. RESULTS

   Fig 8: Von mises stress

   Fig 9 : contact status of wheel and rail

   Fig 10: Contact Pressure

   Transient structural analysis :

   Fig 11: Deformation at t = 0.25s

   Fig 12: Von mises stress at t = 0.25s

   Fig 13 : Contact status at t = 0.25s

   Fig 14: Contact pressure at t = 0.25s

   Fig 15: Total deformation at t = 0.5s

   Fig 16: Von mises stress at t = 0.5s

   Fig 17: Contact pressure at t = 0.5s

   Fig 18: Total deformation at t = 0.75s

   Fig 19: Von mises stress at t = 0.75s

   Fig 20; Contact pressure at t = 0.75s

   Fig 21: Total deformation at t = 1 s

   Fig 22: Von mises stress at t = 1 s

   Time

   Fig 23: Contact pressure at t = 1s

   Chart Title

   1.2

   1

   1

   0.8

   0.75

   0.6

   0.5

   Time

   0.4 0.25 Column1

   0.2 Column2

   0

   23.936 25.062 26.185 27.312

   stress

   Fig 24 : Time vs Stress

5. CONCLUSION

The analysis of stresses in rail and wheel are evaluated. The quasi static load condition is considered for the loading conditions on rail and wheel. Two analysis are performed and the results include :

1. Static Structural analysis :

   • the maximum von mises stress is at value of 34.571 MPa.

   • Contact pressure is maximum at 34.817MPa.

2. Transient structural analysis:

• At t = 0.25s, the von mises stress is maximum at 23.936 MPa, contact pressure at 10.315 MPa.

• At t = 0.5s, the von mises stress is maximum at 25.062 MPa, contact pressure at 10.795MPa.

REFERENCES

1. UIC Leaflet 861-3: Standard 60 Kg/M

2. Rail Profiles-Types UIC 60 and 60E, The International Union of Railways, 3rd edition,2002.

3. UIC Leaflet 510-2: Conditions Concerning the Use of Wheels of Various Diaeters, The International Union of Railways, 4th edition, 2004.

4. A. Sladkowski andM. Sitarz, Analysis of wheel-rail interaction using FE software, Wear, vol. 258, no. 7-8, pp. 12171223, 2005.

5. ANSYS, http://www.ansys.com.