General Mechanical

General Mechanical

Contact with balloon

    • F. Semih Y
      Subscriber

      I want to blow up a silicon balloon (red) in a frame (grey). The purple object is fixed from above and initially NOT in contact with any bodies. The silicon balloon will touch the purple object if pressure is applied from underneath. 




      The results are from partially solved values. Solver errors occurred:


      Physics 1: Contact status has experienced an abrupt change for Contact 3 (Balloon with object). Check results carefully for possible contact separation and review the Contact Best Practices documentation for more information on avoiding such an abrupt change.


      Physics 1: Initial contact status for Contact 3 (Balloon with object) in the model is near open. Consider adjusting initial interface gaps or increasing the pinball size in its contact behavior.


      Do contacts have to be initially in contact for me to compute the reaction forces? Do I have to switch to transient analysis? I am only interested in the final steady state reaction forces/stresses

    • Sandeep Medikonda
      Ansys Employee

      Hi Semih,


      Can you please try the suggestions given in the following resources:


      Discussion 1


      Discussion 2


      Article 1 by a Channel Partner.


      Regards,
      Sandeep


       

    • F. Semih Y
      Subscriber

      The article was really helpful to understand what was going on. From my understanding there are 4 possible solutions:


      1. Decrease mesh size.


      2. Apply integration between mesh grid.


      3. Surface projection contact detection.


      4. Increase pin point size. 


      My simulation becomes rather slow even if I apply the mesh refinement locally at contact region. So solution 1 is not preferred. I looked in the Mesh settings but i couldn't find solutions 2, 3 or 4. Reminder: I use Ansys AIM 19.0 for this operation.


      Also:


      The target object (purple) is rigid and fixed from above. I don't know how to set a body as rigid in AIM. I only need reaction forces on te contact surface of the object and the balloon.

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