Nonlinear-Transient Analysis Drop Test for Assembly

[Anonymous]

Hello, I am currently trying to drop test a model I made in Inventor Nastran, and have setup a non-linear transient analysis for it based on the Ball Impact Exercise directions. However, once I setup all of the idealizations, contact, meshing, constraints, etc. When I run the model no matter how I define the contact, the model will simply pass through the floor and keep going down until it hits the time limit.  Does anyone have any ideas on how to define the contact/constraints so the model hits the floor and then rebounds like it would in real life? 

I can provide files if needed, see attached for animation of the issue.

Ball Impact Exercise: https://knowledge.autodesk.com/support/inventor-nastran/learn-explore/caas/CloudHelp/cloudhelp/2018/...

[Roelof.Feijen]

Hello @Anonymous ,

Please attach your model. That would make it much easier to see what is wrong with the analysis.

[Anonymous]

Here is the link to the folder on Google Drive: 

https://drive.google.com/drive/folders/1YyJYZ0cHyQlMrRjIjn4Avb8EbODdf2qc?usp=sharing

Please use the drop.iam file for the Nastran test, and update me with any suggestions you may have.

Thanks,

Marcus

[Roelof.Feijen · Accepted solution]

Hello @Anonymous ,

You have a contact issue and you needs to make some other changes.

1. Contact between the Binder Base + Support and the efficentfloor. The Activation Distance can be calculated from SQRT(mesh size ^2 + distance^2) = SQRT(0.1^2+0.136^2) = 0.33 in.

2.  I would add a solver contact > bonded type, because you are missing contacts between the other parts and the Binder Base + Support.

3. This solver contact doesn't create a contact between multi bodies. Binder Base + Support is a made up of 3 Solid Bodies. Use the Combine feature to combine them to one single body.

4. I added an extra Mesh refinement (0.15 in) to part Circle Cover v2.4 L:1  because of meshing issues.

5. I changed the time step size to 0.00004 sec (1/(100* dominant frequency). 

Below an animation of the result. 

For some reason I can't attach a simple zip file with a size of 4 MB to this post, so you can download your modified model here. (The link is valid until June, 4th, 2021).

Instead of Structural Damping I would suggest Rayleigh Damping. Take a look at this post.

[Anonymous]

Thank you so much for the help. I appreciate it.

-Marcus