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    • Rahul Ponginan

      Please click here for a short but important announcement   03/26/17

      Dear Users Our Commercial and Academic users around the world can use these same forums here as before i.e. the Altair Support Forum , Commercial users from India with solver queries can go to the Solver Forum for India Commercial Users , Academic Users from India and AOC India Participants are requested to go to the Forum for India Academic Users and AOC India Participants , We will be tending to all queries in all the forums promptly as before, thank you for your understanding. 
    • Rahul Ponginan

      ユーザーフォーラムについて   10/22/17

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User123

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  1. h3d for FEMFAT

    @George P Johnson I changed the output format of the different Loadsteps to "Output2". This is working good. I think Nastran could work as well. Keep that in mind if the question comes up again.
  2. Do you mean statsub(PRETENS) or something else? Where to find this`? I am already using statsub(PRETENS)...
  3. @Prakash Pagadala any update on this`?
  4. h3d for FEMFAT

    I updated it already and it is still not working. It is not finding the results for the stresses.
  5. h3d for FEMFAT

    Hello, i need to know if it possible to use h3d result files of the latest Hypermesh/ Optistruct Version in FEMFAT? When i try to import the results it is working for the geometry only, but femfat can not find the results in the h3d file. Do i need the latest FEMFAT version or what could be the problem with this? Any ideas on this?
  6. @Prakash Pagadala i sent you one of my models, so maybe you can have a look?
  7. Hi @Prakash Pagadala, no sorry this did not help. I build a another model today and i have the same problem as before. But this time the problem also comes up when i use first order elements for the entire model. Its not about the time, the models do just not convert. After a few iterations the calculation starts again and again as shown below. Is there maybe another reason for this happening? Please help.
  8. I found this https://pveng.com/why-use-2nd-order-integration-elements-post/ According to it the error is getting very small when i reduce the element size. But still its not what i am looking for. Could i change the convergence criteria somehow?
  9. @Prakash Pagadala I avoided second order elements near contacts this time but it leaded to the same issue as before. Don't you have any other hint for me? Shouldn't it be possible to do an analysis with friction and second order elements? And by refining you mean that i should refine the mesh as much until i reach the distance between midside nodes and edge nodes? I need reliable results for the tensions.
  10. @Prakash Pagadala I will try this later and tell you if it solves the problem after. Thank you
  11. @Prakash Pagadala Okay i understand, but how i should implement this in my model? Do you mean i should use both types, first and second order, in one model? Should i transform the elements around the contact only and keep the others second order? Do i have to make a clear cut trough the solid model in a speific distance to the contact surfaces? Or just transform the elements near the contact "by hand"?
  12. Hello, I am working on an non-linear-quasi static model with pretensioned bolts and friction contacts. I set up the model with first order elements first, this model was converging fast and results were ok. in order to get the correct tensions i changed the elements to second order. After this i recreated the contacts and pretension to make sure everything is correctly linked to the second order elements. If i run this model it is taking days and doing a few iterations until it starts all over again and again. I use surface to surface contacts and a value of friction of 0,14. I am not sure why this is happening because everything is the same as in the first order elements. Could you please help? I uploaded the out. file and did a few screenshots. Thanks a lot! v4-2o.out
  13. Contact Types forPretensioned Bolts

    Anyone?
  14. Hello, I am still working on pretensioned bolts. I am not sure which contact types i should use for the pretensioning of bolts. In the tutorial for pretensioned bolts is nothing said about it. There is freeze contacts used everywhere, i think this is done to keep the computing time short. Definition for the Contact (Altair Help article: "Contact"): "enforces zero relative motion on the contact surface, the contact gap remains fixed at the original value and the sliding distance is forced to be zero" I think this behaviour is acceptable for the contacts 1+3, the contact of the thread and below the head of the bolt (please look at the attached drawing) but not for 2. I tried different variations (tie, stick, slide) and the results for displacement change significantly! Shouldn't it be some kind of frictional or slide contact for 2? And what is about the orientation of the contact pushout force (morient)? Leave it default? Or Norm? Thank you.
  15. Pretension Contact and surface

    I do have the same question. Yes freeze is for reducing the computation time, but which contact should be used to get correct results?
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