Adding nonlinear bushing joints via Mechanical scripting

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Jimmy He
Jimmy He Member, Employee Posts: 13
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I would like to create nonlinear bushing joints with Mechanical scripting. When I turn on recording, I can see the commands to insert a joint, set the type and scoping, but it does not show the command to run the stiffness entries to tabular in Mechanical so nonlinear coefficients can be entered.

I understand that nonlinear stiffness behavior can be activated via APDL command snippet, which can be added via scripting. This worked for me in the past for a revolute joint, where I was able to insert a revolute joint with default 0 stiffness, then overwrite its stiffness behavior via APDL snippet. The issue with bushing joint is that Mechanical writes out a "TB,JOIN,_jid,,,STIFF" line to the input file by default when the bushing joint object is inserted (this is not the case for a revolute joint). Since the STIFF keyword cannot co-exist with the JNS keywords needed for nonlinear stiffness coefficients, I cannot overwrite it via APDL snippet either.

Any suggestions and comments are welcome!

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Answers

  • Abel Ramos
    Abel Ramos Member, Employee Posts: 35
    5 Likes First Answer First Comment First Anniversary
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    Hello,

    I think something in this like should work. However, please be aware that InternalObject is "not officially supported", so you may encounter some unexpected behavior.

    joints = ExtAPI.DataModel.GetObjectsByType(DataModelObjectCategory.Joint)
    bush=joints[0]
    
    
    bush.InternalObject.ActiveNonlinearCell(0,0) #First Cell, Next Cells (1,1),(2,2)
    bush.InternalObject.JointNonlinearCell("_EnggData_Table",1,1)
    paneTabular = ExtAPI.UserInterface.GetPane(MechanicalPanelEnum.TabularData)
    control = paneTabular.ControlUnknown
    
    #Displacements
    cell = control.cell(2,2)
    control.TriggerBeforeEdit(cell)
    cell.Text = str(1) #Cell Value
    cell.Refresh()
    control.TriggerAfterEdit(cell)
    
    control.InsertRow
    cell = control.cell(3,2)
    control.TriggerBeforeEdit(cell)
    cell.Text = str(2) #Cell Value
    cell.Refresh()
    control.TriggerAfterEdit(cell)
    
    #Forces
    cell = control.cell(2,3)
    control.TriggerBeforeEdit(cell)
    cell.Text = str(10) #Cell Value
    cell.Refresh()
    control.TriggerAfterEdit(cell)
    
    control.InsertRow
    cell = control.cell(3,2)
    control.TriggerBeforeEdit(cell)
    cell.Text = str(20) #Cell Value
    cell.Refresh()
    control.TriggerAfterEdit(cell)