radial displacement (cylindrical coordinate system)

DelanoDelano
i wan to appy a radial displacement of shell cylinder to crimp or expand stent in mecway. For this I need a cylindrical coordinate system. One knows how I can do something like that.
The following picture represents what I need. many thanks for your help

Comments

  • SergioSergio
    Hi, have made some stents in the past. You can use the CCX card *TRANSFORM to relate the inner nodes of the stent to a cilindrical coordinate system:


    *TRANSFORM,NSET=NSET_INNER,TYPE=C
    0.,0.,0.,0.,0.,1.

    Also, your model is simetric, so you can use just a quarter of your geometry or even a sector and use the *CYCLIC SYMETRY card that will also allow you save the results for the whole model.

    I have tried to solve using a ballon with contacts to expand the stent, but the results wher e not good as I wanted.

    Best regards
  • DelanoDelano
    Thank you Sergio for your quickly answer. can you send me a mecway data with this Transform. i dont succeed to do that. many Thanks
  • SergioSergio
    I don't have Mecway on this PC installed, but you need to define first the node set and after use the custom CCX feature on the model tree to enter the card exactly as I write (if the orientation of the model agree with the picture).
  • DelanoDelano
    Okay Sergio! i will try to make what you say. thank you very much
  • VictorVictor
    Writing *TRANSFORM directly, you have to be careful about other constraints on the same nodes that it might conflict with.

    A safer way and simpler way is to specify the displacements as formulas. Radial displacement would have the direction vector of (x,y,0). Mecway will substitute x and y with the coordinates of each node. That automatically generates the appropriate *TRANSFORM cards for CCX.

    Here's an example of circumferential displacement done that way.
  • DelDel
    edited August 2018
    Thank you Victor for your reply. the circumferencial displacement you sent to me is not exactly what i want.i attached a link of video of that i want to do.




    thank you very much
  • VictorVictor
    I used an old example that doesn't quite match your case, sorry. Just change the (-y,x,0) to (x,y,0) in the first displacement constraint in the example to change it to radial. To contract it instead of expanding it, use negative coordinates or a negative displacement amount.
  • DelDel
    Thank you very much Victor.
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