Problems with pretension bolt setup

SteffenSteffen
Hello All,

i start with my first non linear calculation and got some very strange things. I add a pretension on a bolt M18 with 88kN pretension. After calculation I see very big dispacements also next to the spc. I also changed to lenght adjustment but the dispacements are also very big and not possible.

Can someone check the model and help me to find the problem?

Thanks

Steffen

Comments

  • VictorVictor
    There's something strange about your picture showing time = 1000000000 s. I didn't wait for a solution that way though and got a more reasonable looking one by doing this:
    • Add No extra contact step to the CCX branch in the outline tree.
    • Change Time step from 1 s to 0.1 s.

  • SteffenSteffen
    Hi Victor, I changed the things you say but the problem with the big dispacements was still the same. I installed calculix new and now its OK, dont know whats happen but now i am happy. Thanks Steffen
  • FatmacFatmac
    I had a quick look and wondered if there was some interference with the parts, when i ran it the original model with no load or pretension there appeared to be some residual stress produced. Also looking at the mesh in cad -this indicated there may be some overlap of the parts (despite MW suggesting no interference of parts when looking at the 2open crack view). I manipulated the parts to make sure there was no overlap and got it to run sensible. I also made the bolt one piece to simplify the contacts. If the contact between the underside of the bolt head and the upper face of the top block is then changed to unilateral (as I imagine would be closer to reality in most cases, I had difficulty in getting my model to converge without some help to stop rigid body issue before the pretension snugged it up - in this situation i cheated and applied some soft springs to the top block
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