COSMOS Designstar 4.0 Contact problems

[MadsP]

Hi

I have a steel staircase that was created in Inventor and saved to STEP and imported to Designstar.

My problem is that I cannot get several different parts to bond to each other, even though I´ve changed the model so they are a "perfect" match. I ve tried all the different options, the only one that works is rigid connection but it means that the result are sligtly off. But this only works in static, and not nonlinear analysis. "Surface" works but means that everything just slides along the center beam.

It´s seems stupid that the only way to make sure you dont have a contact problem is to build your model as one part when you want to analyse it, (God I hope i´m wrong).

I think I have read all the help files and searched severel forums to no avail.

Please make me sleep well again .

Mads

 

[DonkeyDude]

You should be able to read an Inventor file directly into Designstar.
If not, try using SAT file format rather than STEP.
All the faces that are supposed to be touching should have a proper 'coincident' mate. There should not be any interfernce between any component whatsoever.

 

[MadsP]

Hi DonkeyDude

The first problem with inventor is that it only supports part files, at least in version 4.0. It seems to support it, but if go through the help files there even is a little notice about it.
That of course means you have to start all over everytime you change your model, dammit .

The surface problem is a totally different matter, even without interference I still cant get the option bond/node to work. I think that part of the problem is in the translation from STEP (or other) that minute errors occur, because sometimes I have perfectly matching faces that wont bond, or cant mesh.
The other part is that the help files indicate that for 2 faces to bond they HAVE to be a more than a 100 % equal, and inventor (or others) do tend to make minute adjustment to the lines, wich is obvious when you zoom close.

This is what I think is the problem, maybe you can concur or suggest otherwise?

Thanks

 

[feadude]

Are u trying to join two solids into one or u want to simulate contact forces between two solids?

 

[MadsP]

The staircase consists of several parst in Inventor that I want to calculate in Cosmos, so it consists of several parts in Cosmos as well wenn I translate. But I have to suppress several parts and simplify my loads on the central steel profil, because it cant bond the steps to the beam.
Of course its not without benefitts, the amount of nodes is only a fraktion of the ones needed for the intire model.