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Dear silvia, thanks for your reply
I checked the model but I couldn't find the defect of script.It seems that all of the commands and values are correct! I'd appreciate if you help me.
thanks

Thanks Dr.silvia
I changed nonlinear elements to elastic elements but it didn't affect the period! the results are similar to nonlinear elements. the number of fibers in section are 20 in two direction.

thanks Dr.silvia
I did your advise.by this change period is 2.75sec. it is large,yet!

Hi friends why in this script the period of structure is very large number? T=8.72Sec in 4 story RC frame :shock: I guess that mass value is large but it is correct!!!!!! before thanks #Define units-------------------------------------------- set cm 1; set kg 1; set cm2 [expr $cm*$cm]; set ubig 1e10...

Thanks Dr.silvia
I done your advise but it didn`t affect .
I think for this purpuse some changes sould be done in source code of eigen analysis.Is it right?
and perform of this changes is too hard for me as a beginer operator!!!!!!!!!!!!
Thanks for your advise

Dear Dr.silvia
thanks foy your reply
I 'd appreciate if you help me how can I use add/remove command for mentiond purpose (in midst of eigenvalue analysis for determining the period of structure) for example on 1-story 1-bay, X braced frame.
Thanks before

Thanks for your reply
I want to analyze X bracing system that one of this braces act in + direction and other act in reverse direction.How can I remove/add in midst of an cyclic or eigenvalue analysis?

Hi Dr.silvia
Are there elements such as element death and birth (in ANSYS) in opensees?
if the answer is NO how can I establish this type of elements?
Thanks

Dear silvia
what is the difference between opensees version 2 in size of 10.8MB that exist in website firstly and 5.21MB. it seems that the time of analysis in 5.21MB is less than 10.8MB but the results have some difference (almost slightly shift in analysis graph in my results)!

Dear silvia
I found the solution!
I changed the unit definition from kgpcm2 to $kg/$cm2 and from $kgpm to $kg/$m and $maxnumiter in test normdispincr from 6 to 20.
by this modification the script run correctly!
thanks

Dear silivia
when I omit unit parameters($m,$kg,...) from the definition of length,load and section parameters , gravity analysis run!!!!why?
Thanks before

Dear silvia
I mean that the response is zero,yet!
Dear Thanh Ngo
what is the necessity of mass assignment when we run static analysis?

dear silvia
that is ok. I cant find the reason of problem.Is this related to the eleload command or units definition?

Dear friends why in this script the output of elements is zero?It seems that gravity analysis does not run! Thanks before #Define units----------------------------------------------------------------------------------------- set cm 1; set kg 1; set m [expr 100*$cm]; set cm2 [expr $cm*$cm]; set mm [e...

you mean that the results of analysis is acceptable!!!!