General Mechanical

General Mechanical

Analysis of untightening a bolt stuck due to corrosion

    • BharanKumarA
      Subscriber

      Hello,

      I want to simulate the untightening of a corroded bolt stuck in the joint.

      A common method to remove a stuck bolt is to rotate the bolt slightly in untightening direction then rotate the bolt in the opposite direction and again rotate in the untightening direction to completely remove the bolt. Doing this gradually breaks the bond between the stuck surfaces. I want to analyse this behaviour in the simulation to find out how the breaking of the bond happens between the stuck surfaces concentrating mainly on the thread region.

      How can this type of simulation be carried out? What results have to be checked?

    • 1shan
      Ansys Employee
      I am not aware of any direct model in ANSYS for simulating interaction between corroded surfaces. This may need some Programming effort on your side, utilizing User Programable Features (UPF's) which allow users to model such a complex interaction. Have a look at this interesting article https://www.ansys.com/blog/how-do-adhesives-work . You can also define your own friction model with the user programmable friction subroutine, USERFRIC. Check - Writing Your Own Friction Law part of the Contact Technology Guide
      Regards Ishan.
    • BharanKumarA
      Subscriber
      Thank you for the reply.
      Also, I have done a simulation for a normal untightening scenario. I have applied a rotation and extracting the torque from the result.
      My question here is about the waves that are visible.
      Is it because of the solver that it is visible or has it got anything to do with the physical phenomenon? What is significance of those increase and drop in the torque value? Why is it observed and how can it be eliminated?
      /Bharan
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