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3D Cohesive elements using Nastran Sol400 in Hypermesh

Hi, there is a question I would like to ask the community and support.

I want to solve model of the cohesive element using Nastran (MSC) sol400, but there is no cohesive element in the hypermesh interface. So, I did it manually writing in the '.nas' file, but the cohezive element cards CIFHEX are not supported (not appearing in the hypermesh interface) and i don't understand why ! Should i activate some parameters to be able to use this element card CIFHEX? Have you any solution using NASTRAN Sol 400 (the required solver)?

Best wishes.

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Adriano_Koga

although not a good answer, but it is simply not supported yet for Nastran.

Maybe what you can do is to try importing these into OptiStruct format, that has a wider coverage. I believe it also has the CIFHEX. You might build the model and export the mesh only, and add to your setup in Nastran.

DERGHAME

Thank you for your reply @Adriano_Koga, How i can build/export my mesh only in Nastran if the CIFHEX card is not supported ? I already built my model using CIFHEX in Optistruct and I exported it to ".nas" format. After reading the ".nas" file, the "CIFHEX" card is not recognized.

Adriano_Koga

if you import the .nas card into HM using Nastran user profile, it won't work. It would probavbly be keep as 'BULK UNSUPPORTED CARDS'. So I'd create these elements into HM OptiStruct user profile, export them, but as an INCLUDE file. When you import the .nas, HM won't load the elements, but the contents of your elements will be inside the include file. You just need to keep the include there, and do not re-export it, so that it is not messed up.

Not the best thing, but it would work, probably. Except for the fact you won't see the elements there.

Other than that, work always with OptiStruct user profile for maniputating the INCLUDE file.

Additionally, OS has also Cohesive elements, both based in elements CIFHEX and contact-based.

You should maybe give it a try.