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Autodesk Moldflow 2012 new feature

Non-zero displacement BC for Warp

How to use it in a good way??

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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 the

un-deformed part

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Example how to use it

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Example Bumber

For the example we use a simplified model

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Example

Two settings used: Non-zero displacement BC for Warp

USED

Non-zero displacement BC for Warp

NOT 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

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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.

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Example: how to use it in more detail

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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.

1

2

3

The following slides show results of the workflow.

© 2011 Autodesk

Example Bumber

1

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.

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Example Bumber

2

3 Front of the bumper is fully constrained.

Side

surfaces

are still

“parallel”.

Side surfaces bow

a little bit more

inwards

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Example Bumber

1

2

3

This type of installation creates stress.

© 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.