I've been working through a model and sorting out instabilities and I've reached a point where if I release (pin) any more members I get a type 3 instability somewhere else in the model. After reading this thread I've made a copy of my model and changed all the members to one section size. This seems to get rid of my instabilities. Does this mean I can ignore the type 3 instabilities in my real model?
My model is 95MB so haven't been able to upload it.
Ok, I've saved the model without results and zipped it and it should be accessible by this link:
https://www.hightail.com/download/OGhjb256Y1MzS29LSk1UQw
Note that currently I am getting a type 3 instability in node 758 direction RZ. This is because I have changed the releases of bar 3553 to xxxxff. If you moment connect this member then the instability goes away.
I currently have lots of bracing members which are moment connected but need to be pinned members (preferably with a torsional release at one end too). However if I pin any of them then I get instabilities, but If I change all the section sixes to the same section then the instability goes away.
I would very much appreciate your thoughts on this!
Thanks
mathematical instability - ignore it
if you change all sections onto CHS 406.4x10 instability is not reported
Thanks for the response. I thought that was probably the case but how can I tell if it is an error I can ignore or an error which needs to be addressed?