Learning Forum

[musakucukali]

Hello everyone!

I have a model in Ansys and I want to validate my finite element results with another FEA program such as Nastran. Ansys has a great tool to convert from Ansys format to Nastran format but the thing is I couldn't transfer the contacts, joints and material assignments to the parts from Ansys format to Nastran format. There are something like RBE2's for the joints but there is nothing for contacted bodies. Can anyone who has experience or knowledge on it help me about this problem?

Kind regards

[peteroznewman]

Materials do transfer to Nastran. My main complaint about the transfer is that if I have a multi-body part, because I sliced the part up for meshing reasons, and now there are 12 bodies instead of 1 body, even though all 12 bodies have the same material in ANSYS, I get 12 unique materials in NASTRAN.

Bonded contact (Behavior = MPC) also will transfer to Nastran.

If Frictional contact did not transfer, you will have to recreate that in Nastran.

 

[musakucukali]

Hello @peternewmancsh,

Great to have answer from you. Thank you very much for your informations. As I read from the Ansys converter informations page, linear contacts can be transferred to Nastran as you said. But the problem that I'm facing is, I converted my ansys modal analysis model which has only linear contact as Bonded Contact (Formulation = MPC) and joint as Revolute Joint, to Nastran .bdf and couldn't see any contact cards in the .bdf file. There is only RBE2's for the joints if I get it right but they don't work like constrainting the coordinates like TX,TY,TZ,RX,RY = 0 and RZ = free.  Can you help me with that where I'm making mistakes or missing details? If you want and let me know how effectively, I can share both the ansys and nastran models with you?

 

 

 

[peteroznewman]

 

Hello @derici

My userid on this platform suddenly switched to peternewmancsh for some unknown reason, probably to do with the relatively new platform we are on.  I have been using the userid peteroznewman for many years and I set it back to that today.

There is no longer the ability to attach files on this new platform so if you want to share files you have to put them in a fileshare like Google Drive, Dropbox, Jumpshare, etc. and post a link to that file in your reply. If you do that, also say what version of ANSYS you are using.

 

[musakucukali]

Hello again @peteroznewman,

My userid was my accountid yesterday like you but seems like they're updating also hour by hour. I liked the new forum, hopefully it brings new useful features for us.

The link of the file which has the ansys archieve file and .bdf that I got from exporting Nastran .bdf execution, is in the following link. For future questions about my model, I'm here to explain in detail. Basically, I'm trying to make the same modal analysis in Nastran by selecting some outputs and visualizing the results like mode shapes in Patran and having my validation of Ansys results with another FEA program. I'm not familiar with the Nastran and maybe that's the reason why I'm not converting it in a right way from Ansys to Nastran. The thing is, finite element theory is the same for every program as I've seen so far, but the elements might have different rules and specifications. I hope, I can learn a little bit more while I'm trying to convert my model.

https://jumpshare.com/teams/invite/bc36644c6437d511da8b4c682071620a

Please note that I'm using Ansys 2021R2 version.

Thanks in advance!

 

[peteroznewman]

I joined your Team on Jumpshare, but I don't see any files in the Team or Shared folders.

[musakucukali]

Hello @peteroznewman,

Can you please check it again? It should be in shared folder right now. Sorry, I might forget to invite you to folder.

[peteroznewman]

I downloaded your example. This model is complicated by being a Composite Layup and I find the bonded contact doesn't translate, even through it is MPC contact.

 

I created a simple solid body with bonded MPC contact. Here is a link to the ANSYS archive: https://jmp.sh/GgFyQoX

 

I wrote the NASTRAN BDF file from the ANSYS Modal analysis: https://jmp.sh/wSDnXoR  I was able to run this in NASTRAN. It ran perfectly and gave very similar results.

 

[nguyenminhhieu15122000]

Hello @peteroznewman

May I ask you a few questions?