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friction spot welding modelling

    • tamer elsayed
      Subscriber

      i am simulating a friction stir spot welding process which includes a large deformation and modification of the contact and mesh shape 
      i am applying a rotational speed on the cylindrical tool, after trying all ways, the tool didn't rotate, which lead to incorrect simulation, and accordingly,  reduce the frictional heating and reduce of the volume loss due to wear

      i feel that there is some conflict between the element or contact type that i used with the rotation command, but after my extensive study, i know that the element type and contact type used are mandatory to perform the process
      also, i tried using cylindrical joint instead of rotational velocity, or remote displacement with y rotation, but also not working 

      any help to let the tool rotate

    • Bill Bulat
      Ansys Employee

      If you are not already doing so, my first thought would be to set this up in a Transient Coupled Fields analysis system. The frictional contact this system would create between a spinning rod at the material it touches as it spins should use both structural and thermal degrees of freedom (set keyopt(1)=1): and

      By default, the heat created by friction should be even shared between the contact and target sides of the interface:

      If you locate the Help article below, you will see that the default value for real constant FHTG = 1 (all frictional energy is converted to heat) and default value for real constant FWGT = 0.5 (the heat that is generated by friction is evenly applied to the contact and target side on the contact interface).

    • tamer elsayed
      Subscriber

      Iam really  thankful to your reply 

    • tamer elsayed
      Subscriber

      Dear Bill

      The below link is a screen shots for the steps which i follow. I beieve that i considered all your recommendation but i am still facing a problem 

       

      Binder1.pdf

       

    • Bill Bulat
      Ansys Employee

      You may need to turn to rod as I did in a test case (a very brief transient, with relatively small rotation) that I worked up. I found that a remote point works pretty well for this:

       

      I do see some heat up (thermal response due to contact friction):

      In your model it appears you used a Rotational Velocity object. I tried that initially myself. It inserts a CMOMEGA command into the ds.dat file. It appears this doesn't actually move (spin) the elements. Rather, it appears to only calculate the body forces associated with the specified rotation (stresses due to centripital acceleration). So the mesh doesn't actually spin, and the contact surfaces do not move with repect to each other and so no frictional heat is created. In contrast, my remote displacement does rotate the rod mesh and cause sliding in the contact, so frictional heat is developed.

      I strongly reccomend ramping up rotational speed and axial plunge gradually (stepping suddenly to full values might cause convergence problems). It might take a large number of time steps to perform this simulation.

      I do NOT think the CMROTATE command (to specify rotation and internal contact sliding without actually moving the mesh in static and modal analysis used to perform brake squeal analyses) will work in a friction weld simulation such as yours. I tried this too and saw neither rod rotation nor a thermal response. I believe you have to "manually" turn the rod mesh as I did with a remote point to get frictional heating response from the coupled field contact elements.

    • tamer elsayed
      Subscriber

      First i am really  appreciate your cooperation.

      Second I tried to apply a remote deplanement on a remote point and still not working 
      Then, i tried the following options:
      1- the remote displacement including rotation only, 
      2- the remote displacement including rotation and displacement 
      3- the remote point options is coupled 
      4- the remote point options is deformable 

      and all options didn't lead to rotation

      please find below the link for my ANSYS file

      16.wbpz

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