join elements with different material propetries 1

[charizard]

hi, i'm a beginner using Patran.
I have to join 2 solid elements that have different material properties..I can't make an equivalence.. so, how can i do it? somebody knows?
Thank you!

 

[meolo2002]

I'm a beginner like you :-D, but i think the only way is put some contacts (bonded).

 

[franc11HD]

Different properties should not make two solid element impossible to joint. But having different mesh might since the nodes are not coincident. I am guessing that this your situation.

If you can't equivalence, than I suggest to remesh trying to make the mesh as equivalent as possible. You can also, as suggested by meolo2002 using SOL600 of SOL400 of SOL101 (MD Nastran) to create a glue contact between the two surfaces that will bond together. But being a beginner, I would'nt suggest that approach, because it can be hard to solve and could cause other errors.

You could also create a center node between the two surfaces you want to join and create RBE3 elements betwenn this node and the nodes of the two elements. This will bond them together.

There is multiple way of doing this. You might want to add a drawing or picture to your post so we can understand better the situation.

 

[charizard]

i attach a picture decribing the situation.. i should join the green element to the white element... equivalence doesn't work..
thank you!

 

[franc11HD]

may be that is me, but I don't see any attachment...

 

[zuhaitz]

I want to be a beginner like you, couldo you tell me where can I download the Patran/Nastran software?

Thanks

 

[franc11HD]

charizard,

Ok, now I see the attachment...

Seems to me that this is a two part model. (white and Green). I see in the green model 4 bolt holes. Do those holes are used to attach the green part to the white one? If so, then this is all you need to care about in terms of attachment.

As a start, you can use RBE3 elements that link all the hole interior nodes of the holes to one nodes on the white solid. Do this four times to represent the four bolts. This is a crude way of modeling fasteners, but if you dont really care about the fastener loads an/or the stresses around those hole, that will do the job. You can look into CFAST as well, could work.

Then if you are telling me that the green part and the white part are in fact one and only one part, then glued contact could be the "fastest way" to attached them together.

It all depends on what your are trying to achieve in the simulation.