General Mechanical

General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

bolted metal plate strips – wrong stress on shell

    • bokaJ
      Subscriber

      Dear ladies and gentleman.


      I have a problem with my structural analysis.

      I want to simulate 2 metal plates which are bolted together, as you can see in the following picture.

    • peteroznewman
      Subscriber
      nOpen the Geometry in SpaceClaim, go to the Workbench tab and use the Share Button. That will make the circular edge on the outside of the face used to represent the bolt head to share nodes with the rest of the surface of the plate. That will let you delete all the Bonded Contact, which will help simplify your model.nDid you watch my video series? https://forum.ansys.com/discussion/1217/bolt-pretension-clamps-two-plates-togethern
    • bokaJ
      Subscriber
      Thank you very much for your answer.nThe deformation looks a lot smoother, as you can see in my following picture. Alos the stress peaks at the bonded sections are gonenBut there is still a big difference to the normal stress of the 3D modell as you can see in the following picture.nI have turned lager deflection off in both cases, so I can better compare it to my hand calculation.nThe direction of my forces are definded by components.nYes, I have already seen your videos.nThank you therefore, they are great!! I built my modell like yours.Could it be possible, that I need more integration points in shell thickness direction?.Thank you very much for your helpnBest regardsnbokaJnn
    • peteroznewman
      Subscriber
      nThe solid model is built along the X axis while the shell model is built along the Z axis. Can I trust that the geometry, loads and supports are identical?nOnce two models are laid out with the same conditions, the difference between the stress in the shell elements should be comparable to the solid elements.n
    • bokaJ
      Subscriber
      Thank you for your answer sir.nnI am sorry, that it is a little bit confusing because the coordinate system is not the same in the two examples.nSo i did I did it again and used the same coordiante system therefor.nAbove you can see the dimensions of the model. I prooved it again, the dimensions of the two models are the same.nnAt first you can see my settings for the solid model:nI did not share the topology in the geometry, So I can give every sinlge subsection of a part a mesh which fits best. ncontacts:nnnn
    • bokaJ
      Subscriber
      _____________________________________________________________________________________________________________________________________________________________________________________nshell and beam model:ndimensions:nnbeam settings:nnnContacts:nnnnnIn this case I shared the topology in the geometry tool: nnmesh:n
    • bokaJ
      Subscriber
      forces and boundary conditions:nnnnnnnanalysis settings:nnnnnormal stress in z-direction:nnn
    • bokaJ
      Subscriber
      The result of the 3D analysies is close to my hand calculation(25N/mm^2, 175 N/mm^2, -125 N7mm^2). But the result of the beam and shell model is far away from the others.nnIf I turn on large deflection I get the following results. In this case these two reluts are in my opinion also too fare away from each other.n
    • bokaJ
      Subscriber
      I hope that I provided all the information to you which you need to help me.nIf you need further information, please ask me.nnThan you very much sir! n
    • bokaJ
      Subscriber
      mesh:nnnnnnnanalysis settings:nnnnormal stress in z-direction:n