Hi

In Nastran, SPC (SIngle Point Constraint) is used to specify boundary conditions. Take a look here

http://www.scc.kit.edu/scc/sw/msc/NasDirect/Nas_ED_SPC.html

http://www.princeton.edu/~dynaflow/femgv/manuals/prenast/node34.htm

Hope this helps

Claes

Dear Mr Abdollahi,

since it is a long time you posed the question you have probably already solved this.

Generally, if you want to set boundary conditions in ADINA Structures or ADINA-CFD you need element face sets and node sets. Those can be created in the meshing software, and when you import the Nastran file the shell elements covering the volume mesh boundaries can be translated into element face sets and node sets. You can also create these in AUI by chaining element faces, for instance.

At my work we create all mesh in ANSA and use NX Nastran .nas files to read the mesh into AUI. It works very well.

Best regards, Kenth

Dear Mr. Nilsson,

I am trying to do something similar; I need to run my strong-coupled FSI simulation with adaptive meshing on a Nastran imported mesh. However, in ADINA-CFD, when I import my fluid mesh with 3D and 2D elements (PSOLID and PSHELL cards in Nastran), I can never seem to make the shell elements appear in my element groups. This is necessary to run the adaptive meshing routine. Have you ever faced this issue?

Regards,

Ullhas

Dear Mr Hebbar,

Just two general checks first:

1. When you import the NASTRAN file, do you set Create BCELL from Shell Elements = Yes

2. Under Control/Miscellaneous you shold set ALE and SBC on nodes or elements when you have an imported mesh and use nodesets and elfacesets.

I must look at an example, so I will come to back to you.

Best regards, Kenth

Dear Mr. Nilsson,

Yes, I have ensured both. So here's the funny part - When I set the create BCELL=YES, and set the ELFACESETS and NODESETS options to follow, I can create the face sets and nodesets with no problems. However, if I don't check the options, ADINA just ignores my shell elements.

From what I understand, for the adaptive meshing routine, the shell elements need to be in the element group tree to ensure a .adp file is created and the solver knows the boundaries of the domain when remeshing the NASTRAN geometry. However, I have only been able to create face sets and nodesets. Does this make sense? I will contact support tomorrow and post back here.

Thanks!

Ullhas

Dear Mr Hebbar,

what help did you get from the support?

Best regards, Kenth

Dear Mr. Nilsson,

I managed to get the adaptive meshing routine running. My understanding was slightly incorrect, I can have my shell elements as face sets and node sets without a problem for adaptive meshing, ADINA creates a faceted surface for your fluid mesh. The only thing one needs to ensure is that there are no skew systems applied for the fluid mesh.

Thanks for your help!

Ullhas

Dear Mr Hebbar,

I am glad that you got help from the support at ADINA R&D. I have had enormous help from them during the years and they are very responsive. And they know their codes very well.

OK, then the solution was as I imagined. At work we do all meshing in Ansa ,from Beta-CAE, and import the meshes via the NX Nastran format to ADINA. Both for ADINA Structures and ADINA CFD the volume mesh is covered with shell elements, which are converted to sets in ADINA, to apply all kinds of boundary conditions, loads, contact surfaces, flow boundaries, etc. It works very well. Often we also post-process in Meta the .op files from the ADINA solver. It is structural models with typically 1e5 to 5e6 elements so the graphical handling can be quite heavy.

I hope we will see you work in the future.

Best regards, Kenth