Civil Engineering Association

RE: ROBOT2009_2011 DYNAMICS ANALYSIS PROBLEMS
I've noticed no such problems with versions 21 to 2011. Rigid diaphragm works properly 100%. Maybe your model isn't properly red by 2011 version.

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Hi Mario M
My Friend I did many trails with Robot 2010 and 2011 and I am sure Rigid diaphragm
is a great bug inside robot when you apply dynamic analysis
I tried to solve 40 floor 60 floors and 80 floors towers
But rigid daiphragam+ dynamic analysis can lead to a fatal mistake with robot
I have sent this conclusion to Autodesk but no any responding from any one
Pleae be careful when using Rigid daiphragm specially with Large models

mecheil.edwar, can you upload a small sized model where you had problems with the diaphragms?
I ll give it a try. If there is actually a bug there i can contact autodesk where i'm subscribed user and come back any information they provide me.

MarioM,
It is from previous version of robot Rigid Links can creat a problem with dynamic analysis
Second isuue RSA2010 has got service pack 2 for this problem and autodesk promise this solve the problem but still sometimes not working , you can also visit web site of autodesk and read the service pack notes for rsa2010.

I got many dengeriuos problem with response spectrum analysis By UBC code with robot
It is a long story .. Finally I decide to use Etabs it is working very well for large models specially with High rise building .. No Headech for response spectrum analysis no bugs with rigid diaphragam and many other issue...

you can do some trials with large model say tower 80 floors and use rigid diaphragm and see what will happen...
Believe me it is a real bug with robot

Taking into account the effect of the diaphragm robotbat software, the dynamic analysis of spatial structures without WALL does not generate any error messages.
but if we introduced the WALL, the analysis gives error messages.
more severe versions of this software "robotv97, robot robot v21 14.5 to VERSION 21 " work very well without any error message while taking into account the effect of the diaphragm and the addition of WALL

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Problems caused by robot forced me to the robot dropped out.
etabs software is the best product

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other error message " istability type3

I Agree with you Etabs is the best
For all building types you can used it and trust Etabs results without any doubt
Robot is good for small buildings and steel structurs (frame elements) and to design all steel connection details.
For High rise building it is not recommended to use robot

if I use the robot software I prefer robotbat robot17.5 version that is stable, considering all types of buildings without any errors.

Hello,

I’ve experienced similar problems in past models, especially for high rise buildings. When you check the reported node that supposedly has the instability, most of the times it doesn’t make sense. Anyway, what I’ve found is that still the model is reliable. If you check modal deformations and periods they are in the expected range. Also if you check seismic base shear it is also correct. So it’s probably some numerical bug that they haven’t been able to fix since past versions. Sometimes changing solution algorithm also helps.

Regards,

You should try MiDAS/Gen

I remade the dynamic study of the same structure with the version robot17.5.
as agreed, no error message to report

hi you!
could you talk to me type to define diaphram in robot . i do not look for it . and for assigning force at center of mass , if you known , could you indicate me . thanks so much