Autodesk Robot Structural Analysis

[#1]

Hi,

I am trying to run a "Analyse Non Lineaire" on a model that include seismic loading. (see attached)

I have some problems :

- I have around 10 on 47 seimic combination that have NO "convergence"

- I don't no if there is a report where the calculation errors are written on to debug

- the seismic cases without vertical dead load is "converging". No sense.

- the ground reaction presure is not true on combination that includes seismic loads (I found manually unfavorable presure)

Thanks for helping

Cdy

[#2]

Sorry it's fine now,

I had a problem on my Newmark combinations.

Somebody now why when modal sismic analysis is running on a non linear model the combination are linear for all of those that includes sismic case.

Combination without modal sismic cases inside are non-linear combinations.

Other problem : the seismic cases : Robot doesn't take into acount the uplift free in these loading cases, isn't it?

I think Robot is wrong. It is very dangerous.

I can I solve the problem? Maybe If I convert manually each load into an horizontal static load for run my model in static non-linear only?

I attach the last model for exemple

[#3 · Accepted solution]

Please read:

http://forums.autodesk.com/t5/Autodesk-Robot-Structural/Uplift/m-p/3320823/

http://forums.autodesk.com/t5/Autodesk-Robot-Structural/Barre-de-treillis-traction-compression-vs-s%...

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[#4]

Hi,

It is exactly what I need to confirm my doubts.

Thanks a lot

I also understand now problem métallic frame analysis I had in the past.

It is quite dangerous ! calculation is runing well without any warnings.

I am usual to make a separate model to design my rafts. It is fine.

Thanks