### Non-zero displacement BC for Warp

```Autodesk Moldflow 2012 new feature
Non-zero displacement BC for Warp
How to use it in a good way??
Non-zero displacement BC for Warp
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

Requirements

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 the
un-deformed part
Example how to use it
Example Bumber
For the example we use
a simplified model
Example
Comparison BC used and not used

Two settings used:
Non-zero displacement BC for Warp
NOT USED
Add regular BC to constrains the
part for warpage analysis (6dof)
Non-zero displacement BC for Warp
USED
Part will be assembled at the car
using this distances
Example
Due to the assembled
situation, the component
moves inward. It thus
has a completely
different shape form
compared to the not
assembled situation.
The BC simulate the assemble
situation and the result shows
the part deformation in this
situation.
Part deflect for the not assembled situation.
Example: how to use it in more detail
Workflow
1
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.
2
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.
3
Assume that the bumper is in fully contact at the front of the
car. Analysis 3 should take this into account.
The following slides show results of the workflow.
Example Bumber
More part shrinkage in x-direction
Side surfaces
bow in-wards
1
Part shrinkage in x-direction
New deformation as a result of the
attachment of the side surfaces.
This distance
needs to be
mold to
compensate for
the shrinkage
Side
surfaces
now
“parallel”
2
Example Bumber
2
Side surfaces bow
a little bit more
inwards
Front of the bumper is fully constrained.
Side
surfaces
are still
“parallel”.
3
Example Bumber
1
2
This type of installation creates stress.
3
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.