Problems with instability!!!

[mled]

I have problems with instability in a large steelconstruction. How can I send you the Robot file?

[Rafal.Gaweda]

http://forums.autodesk.com/t5/Robot-Structural-Analysis/Sending-bigger-files/td-p/3795062

[mled]

Thanks Rafal!

Here's a link to the file:

https://www.sendthisfile.com/646ACAZkFd3gngVEdtpbZAbE

I use Sparse M and I get instability type 1 and 2.

Cant seem to understand why!!

Time is very limited! Please help!

[Rafal.Gaweda]

First remarks:

- delete isolated nodes

- some bars not connected to structure - delete them or connect them or apply supports

[mled]

These notes and bars have no effect on the stability issues!

[Rafal.Gaweda]

Did I mention they have? Just general remarks.

In general wrongly defined releases and...:

- node 33375 shoube be on node 331

This is my way of correcting - If you do not agree with it correct releases by your own

- change solver onto Automatic or Skyline to see all instable nodes and correct releases \ model to get rid of them

- bars 16 21 23 25 29 48to51 62 84 101to137By12 104 112 134 136 160 168 172 174 217   289to291 295 297 310to316 350 449 450 554 with fixed -pinned1 release

- 46  103   47 106  2 with fixed -pinned2 release

- please check your model - some bars have huge deflections

- 3 instabilities remain - add load in direction of instability in node given in instability warning messge check displacement \ rotation results and correct model \ releases. Example :

MY file attached