Seismosoft | Earthquake Engineering Solutions

Hi
I am modeling a regular steel structure:3story & braced frame.when i analysis this model with Dynamic time-history,this error appear:
Time= 7.97211, dt= (Iter: 1 => fbd_Ite)
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Unable to apply the next load step. Analysis terminated
Total Analysis Time: 1h:20min:16s
I send my model to your email.
Thanks a lot.

There are numerous reasons why your model is diverging, structural (e.g. the model has failed and cannot sustain the load) and non-structural (e.g. not appropriate modelling of constraints).
Refer to the help system on the articles about convergence, and carry out a forum search, where you will find plenty of information.

Dear macivil,

We looked into your model, and, as anticipated by Stelios Antoniou, the "problem" is that your structure is collapsing under the imposed load.

Indeed, if you look at the deformed shape (amplify it a bit), you will be able to see clearly that the braces are buckling (especially at the top storey).

Also, if you check the strains at the braces, you will realise, again especially for those at the top storey, that their deformations reach extremely high values, especially in compression, clearly denoting buckling.

In other words, and as often is the case, there is no error with the model or the program, but rather simply the case of a structure subjected to an amount of loading that it cannot sustain.

Hope this helps,

Seismosoft Support

dear supporter & Stelios Antonious
Thank you for your help.