General Mechanical

General Mechanical

Simple assembly model cannot solve

    • sombodyfromtheworld
      Subscriber

      Solver takes very long time and using too many iterations. Any help would be appreciated to point where i make mistake, please see the screenshots from a setup. Two sub-assemblies with shared topology. Material is standard Structural Steel

    • SaiD
      Ansys Employee
      Hi,nFrom the pictures attached, it looks like you have a very fine mesh which might be causing the long solve time. In addition, all your contacts are frictional which are nonlinear contacts i.e. their status can change from closed to open during the analysis. This adds to the solve time. If you want a quick initial solution (which need not be the most accurate):nChange all the contacts where you don't expect relative motion to be Bonded. Better yet, change the geometry to Share Topology between components that don't move relative to each other. This will eliminate the contacts between those components.nUse a coarse mesh initially. When you are sure the simulation runs without errors or warnings, then refine the mesh to get a more accurate solution.nnHope this helps,nSain
    • peteroznewman
      Subscriber
      The solver makes as many iterations as it needs to compute equilibrium. The more nodes and elements you have, and the more contact you have, the longer it takes.nSome things you can do to make the solution take less time is to:n1) limit contact to smaller facesn2) replace the thin-wall solids with midsurfaces so that you can replace solid elements with shell elements.nn
    • sombodyfromtheworld
      Subscriber
      Thanks for your suggestions, I actually need to use nonlinear contacts. Is it possible to replace thin-wall solids with shell midsufaces and combine them in one assembly with other solid elements?n
    • peteroznewman
      Subscriber
      Yes, you can have an assembly of parts where some were midsurfaced and have shell elements while others were left solid and have solid elements. You can have contact between shell elements and solid elements. Just check the box in the Contact Definition to Include Element Thickness and Mechanical will automatically put the contact elements half a wall thickness away from the shell elements at the midsurface.n
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