Recorder for Fiber Sections

[uxb5003]

Hi,

I have defined the columns for my bridge using force beam column elements and fiber sections. I'm recording the deformations of the column under different seismic loads. the command I've given for defining my recorder is as follows:

recorder Node -file $datadir/$Mkdir/$Folder/$Angle/Node50001_RotX.out -node 50001 -dof 4 disp
recorder Node -file $datadir/$Mkdir/$Folder/$Angle/Node50001_RotY.out -node 50001 -dof 5 disp

recorder Element -file $datadir/$Mkdir/$Folder/$Angle/Curvature_Element502.out -ele 502 section 5 deformation.

Now, the time history I'm applying has dt = 0.02 sec and total duration is 59.98 sec, thus giving 3000 time steps. Hence, when I run my analysis, the above defined recorders should record 3000 points of corresponding data, 1 for each time step.

I want to know whether my understanding is correct? This is because my recorder is showing 12000 different data points. Also, each recorder terminates with different end time. For eg. One recorder shows me 12000 data points, while the other shows me 4000 data points. Can you please let me know how does the recorder defines these data points?

Thanks.

[vesna]

Data points within a recorder are defined based on the number of analysis steps to perform defined within "analyze command". Number of rows of data in your output file should be equal to the number of analysis steps.

Look at the output files after the end of the analysis. For the output files to be properly written add "wipe" command at the end of your file (after the analysis is performed). Output files are written after completion of the analysis and destruction of the model.

[uxb5003]

Hello Vesna,

Thanks a lot for the response. I made the changes as you suggested, and the problem got resolved.

However, I'm facing a new issue. For a given orthogonal set of ground motions, I have to change the angle of attack from 0 to 180 degrees, with a change step of 15 degrees. Hence, I want to loop the analysis case, which will enable the software to run analysis and compute the response for each of the 13 cases. If I add the "wipe" command at the end of the first analysis, I would have to run the other cases manually, by changing the ground motion file name for each of the cases. This doesn't allow me to automate the process. I tried using wipeAnalysis command, but that doesn't solve the problem. Can you suggest a work around? In the meantime, I'll try to figure out a way as well.

Thanks,
Unmukt.

[vesna]

If you want to automate the process here is a way to do it:

set numRuns 13
for { set j 1 } { $j <= $numRuns } { incr j} {

wipe
...
define your model
...
define your load and recorders (output files should have variable names that will change for each ground motion)
...
perform analysis
...
}
wipe

[uxb5003]

Hey Vesna,

Thanks for your response.Sorry for the late reply, but I was trying to work out a process myself, so didn't see the post. I actually came up with the same process. I tried different looping methods, but this one worked. Thanks a ton for your help.

Regards,
Unmukt

[vesna]

I am glad you solved it yourself.