© 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 the un-deformed part

© 2011 Autodesk Example how to use it

© 2011 Autodesk Example Bumber For the example we use a simplified model

© 2011 Autodesk 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

© 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 Example: how to use it in more detail

© 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 The following slides show results of the workflow.

© 2011 Autodesk Example Bumber 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 Front of the bumper is fully constrained. Side surfaces are still “parallel”. Side surfaces bow a little bit more inwards

© 2011 Autodesk Example Bumber 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.