Experience with Substructures?

[choopo]

Hi,

I've gone through the docs and I've understood what substructures are about and how they are (theoretically) done. However, in practice, I'm having all sorts of troubles.

I was wondering if someone has an instruction/procedure for a hussle free implementation of substructures.

Something along the lines:
- create a CAE model as any other
- put nodes that you wish to retain in a set
- ...
- write an input file
- edit the step
- ...

My biggest problem is how to position element nodes at the usage level. For instance, I have a 3D beam (a proper 3D structure, not a wire) and I want to replace the middle of the beam with an equivalent substructure i.e a direct replacement

====================== <-- this to become

===={substructure}==== <-- something like that

The retained DOFs are all DOFs of all nodes accross the cross-section.

How could this be done?

The way I've done it results in a warning that goes for every node I've used to attache the substructure and no load gets trasmitted to and from the substructure.

The warning is:
***WARNING: THE COORDINATES DUE TO *SUBSTRUCTURE PROPERTY ARE OUTSIDE SPECIFIED TOLERANCES FOR ELEMENT

Thanks