General Mechanical

General Mechanical

Warning :The rotational angle for Cyclic/Periodic……Please confirm the geometry is symmetric.

    • Rashi
      Subscriber

      Dear All,


       


      I'm currently doing a stress analysis of an impeller. To reduce computational load I'm using cyclic symmetry, and I get this warning.


      "The rotational angle for Cyclic/Periodic adjacent faces are shared by a common edge, but the angles do not match. Please confirm the geometry is symmetric."


       


      Do I have to worry about this  warning? I have correctly selected "Low section" and "High section".


       


      Thank you.

    • Sandeep Medikonda
      Ansys Employee

      Hi Rashi,


      Please post an image to explain? 

    • Rashi
      Subscriber

      Hi Sandeep, 


      Please find the attached image. As you can see I have included image of the whole Impeller, and 1/10th part used for cyclic symmetry.


      Please let me know if any further data is required.


      Thank you.


    • Sandeep Medikonda
      Ansys Employee

      Rashi,


      So that error would make sense right? you don't have flat cuts on either side. There is an angular mismatch. Please see this section from the help and the following resources on setting up something like this:


      Resource 1


      Resource 2


      Regards,
      Sandeep
      Guidelines on the Student Community

    • Rashi
      Subscriber

      Dear Sandeep,


      Thank you very much for your reply. I understand what you are saying. But I found some help file on ANSYS APDL which says this can be done for such geometry. 


      https://www.sharcnet.ca/Software/Ansys/16.2.3/en-us/help/ans_thry/thy_tool14.html


      https://www.sharcnet.ca/Software/Ansys/16.2.3/en-us/help/ans_tec/teclinearpertmodel.html


      My issue is if this is possible in APDL why is not possible in Mechanical Workbench?


      BR,


      Rashiga


       

    • Sandeep Medikonda
      Ansys Employee

      Rashi,


        Please remove those non-approved references from sharcnet. I request you to use ANSYS help which is updated and officially maintained.


        Coming to your question, You can use your sector and what you have is just a warning. Your results are still valid as the angle α (in degrees) spanned by the sector satisfy this relation Nα = 360, where N is an integer. 


        The reason I believe you are seeing that warning is you have a sharp change in the angle of those 2 geometric faces. You see when it is straight or curved it is still one edge/face. Try cutting your model, as shown in this document on slide 22 (Which has the exact same geometry as yours).


      Regards,
      Sandeep

    • Rashi
      Subscriber

      Dear Sandeep,


       


      Thank you very much for your explanation. 


       


      Best Regards,


      Rashiga

    • j.drozdowski
      Subscriber

      Hello I've got different problem with symmetry cyclic region. My case is quite simple. I've modeled one quarter of silo and set up cyclic symmetry region as shown on picture below. Using tips from this topic:

      https://forum.ansys.com/forums/topic/ansys-workbench-symmetry-region/?order=all#comment-92a78035-91b1-4d64-b993-a9c8011c5210

      I've managed to display whole silo after meshing. I tried both methods "half" and "full" with different angels.

      The problem is that I cannot display whole silo in results. It is just disappearing. What I'm doing wrong ?

    • EmilioPuglia
      Subscriber

      Im facing the same issue, did you find out how to display it in the results?


       


    • Rashi
      Subscriber

      As I remember to see the results of the full geometry you should turn on "Beta options" in workbench. Afterward, you add a "symmetry" function and set the type to polar then it will work.


       


       

    • EmilioPuglia
      Subscriber

      Yes, further than than that, under the solution tab/cyclic solution display, you should type the number of segments you want to display. (Ansys 2020 R1)




       


       

    • j.drozdowski
      Subscriber

      Yes. That is the solution that I was looking for. Thank you

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