© 2011 autodesk autodesk moldflow 2012 new feature non-zero displacement bc for warp how to use it...
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© 2011 Autodesk
Autodesk Moldflow 2012 new feature
Non-zero displacement BC for Warp
How to use it in a good way??
© 2011 Autodesk
Allow use of a non zero displacement boundary conditions to simulate the effects of mounting a part during an assembly operation.
Key Features
Use forced displacement to consider the assembly-induced
Deformation and stress for linear elastic analysis
Available for midplane, dual domain and 3D
Limitation Should be use with small deflection analysis only
Non-zero displacement BC for Warp
© 2011 Autodesk
Non-zero displacement BC for Warp
Requirements Apply your constrains how you would like to constrain your mold
cavity to fit your final assembly position
Ensure rigid body motion is fixed Constrains created must fixed 6 degrees of liberty It can be part of your constrain
Fix nodes, or displacement at nodes Displacement values should consider the un-deformed
part as references Automatic correction on those constrains will be applied
on warp part to be equivalent to the constrains on theun-deformed part
© 2011 Autodesk
Example
Two settings used:Non-zero displacement BC for Warp
USED
Non-zero displacement BC for WarpNOT USED
Comparison BC used and not used
Add regular BC to constrains the part for warpage analysis (6dof)
Part will be assembled at the car using this distances
© 2011 Autodesk
Example
Part deflect for the not assembled situation.
The BC simulate the assemble situation and the result shows the part deformation in this situation.
Due to the assembled situation, the component moves inward. It thus has a completely different shape form compared to the not assembled situation.
© 2011 Autodesk
Workflow
Set 6DOFs and run an analysis without using the Non-zero displacement BC for Warp to get the shrinkage values. That will help to identify if the mold size is correct and you can see the deflection of your not assembled part.
Add the Non-zero displacement BC for Warp. Run the analysis again. The deflected shape show the deformation of the part as a combination of warpage in the assembled situation.
Assume that the bumper is in fully contact at the front of the car. Analysis 3 should take this into account.
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2
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The following slides show results of the workflow.
© 2011 Autodesk
Example Bumber
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2
Part shrinkage in x-direction
More part shrinkage in x-direction
Side surfaces bow in-wards
This distance needs to be added to the mold to compensate for the shrinkage
Side surfaces now “parallel”
New deformation as a result of the attachment of the side surfaces.
© 2011 Autodesk
Example Bumber
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3Front of the bumper is fully constrained.
Side surfaces are still “parallel”.
Side surfaces bow a little bit more inwards
© 2011 Autodesk
Workflow use for
To show the deflection of a part. Use the assembly situation to show the deformation of a part. You can identify the amount of stress increase between the
origin deflection and the assembled situation.
That workflow can also be used if a specific measuring device is used to measure deflection.
This workflow should not be used for non-linear deflection.