Shreedhar Sahoo

About Me

I am a PhD scholar (Prime Minister Research Fellow) in the department of Mechanical Engineering at IIT Kharagpur, India, under the supervision of Prof. Vikranth Racherla. My research area is Contact Mechanics.

Please find the my curriculum vitae here.

I am currently working from Centre for Railway Research at IIT Kharagpur.

Research Area

• Contact Mechanics is the study of deformation of two bodies when they are touching each other. It used in the study of tribology, contact stiffness, electrical contact resistance and indentation hardness. Heinrich Hertz is pioneer in this field who solved the contact problem and also developed it into a software CONTACT, which provides solution a varigated set of contact problems.
  
• Hertzian Contact Theory first ever proposed theory by Hertz. It is a classical theory of contact mechanics. Even though the derivation of the theory is relatively difficult, the final solution is a set of simple analytical equations relating the properties of the system to the developed stress at the contact.
• Creep forces modelling , the tangential frictional forces generated at the contact are termed as creep forces. When systems become more and more complex, evaluation of these forces become more complicated and time consuming, much research has been done to establish fast algorithms for their computation.
• Wear Modelling , wheel and rail wear is fundamental problems, they affect stability and comfort of passengers and can also lead to derailment. Many experimental procedures have been laid for the purpose to model its different parameter evolution.

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Education

• Indian Institute of Technology Kharagpur (IITKGP) [ From 2019 ]
  PhD Scholar (Prime Minister Research Fellow), Department of Mechanical Engineering
  

• Indian Institute of Technology Kharagpur (IITKGP) [ 2014-19 ]
  Under Graduate Student, Department of Mechanical Engineering
  CGPA 9.24,

• Higher Secondary Board [ 2011 ]
  FIITJEE, Visakhapatnam
  Score 96.3%,

• Secondary Board [ 2009 ]
  Central Board of Secondary Education
  CGPA 10
  

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Research project

Investigating contact mechanics experimentally through inverse formulation using temperature monitoring

Rail wheel monitoring is an active research field all over the world. Several commercial products exist in this research field. With increasing speed of the trains, safety and ride quality are major concern. Therefore, much attention is needed towards developing advanced continuous monitoring systems, which have a prognostic methodology in contrast to the traditional diagnostic approach. In the diagnostic methods, the action is taken only after certain damage is done. Our attempt here is to develop a prognostic methodology for maintenance and reduction of wear and tear of the rail wheels in the scenario of disc braking, thereby increasing the wheel life. Disc braking employed in high speed trains leads to undesirable phenomena like wheel flats, wheel sliding, wheel locking and wheel spalling, which when unchecked for can lead to wheel failure and also catastrophe with heavy toll on life. Due to high braking torque, wheels get locked faster (within 1- 3 secs) which results in higher cooling rate, thus increasing the chances of brittle martensitic phase transformation. Our aim is to predict the friction coefficient based on inputs from temperature sensors and then use this information to set the braking limits. Such information can be used to find the braking distance as well. It is also important to assess the overall performance of the rail wheels, which will help the further development of railways. The development of the prediction model are as follows:

Forward problem
• Solving the rail vehicle dynamics problem
• Solving the contact mechanics problem
• Solving the heat transfer problem

Inverse problem
An inverse algorithm will be applied to the previous framed forward problem by using the state of the art technique like variational auto encoder. The model will predict the running conditions like friction coefficient at the rail wheel contact interface taking temperature as its input.

Experimental validation
The model is then calibrated on rail wheel contact simulator. Rail wheel contact simulator is a experimental setup with two discs mounted on shafts placed in contact with each other. The two discs are profiled like wheel and rail profiles respectively.

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Courseworks during Ph.D

Finite Element and Boundary Element Methods (Graded: Ex), Railway vehicle dynamics (Graded: Ex), High performance Scientific Computing (Graded: A), English for Technical Writing (currently enrolled)

Contact

Email: shreedhars@iitkgp.ac.in
Ph: +91 9734522163