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can not obtain modes of vibration in eigenvalue analysis
Posted: Thu Oct 07, 2021 12:10 pm
by liyanwentj
The eigenvalue analysis is defined following the gravity analysis.
In the postprocess, the gravity analysis results can be shown and the eigen analysis result .txt file is generated, while the mode of vibration can not be shown in the postprocess.
Mode of vibration has been selected in the recorder.
The model file is attached
Re: can not obtain modes of vibration in eigenvalue analysis
Posted: Fri Oct 08, 2021 8:15 am
by marafini.f
Hi linyanwentj,
I just did a class on this topic, you can find the video recording and material here
https://asdeasoft.net/?get-started-webinars#w17
The eigen command does not call the command record automatically in OpenSees, so you need to add it manually.
Create a customCommand in the analysis steps and simple add the word record in it.
You will be able to visualize your results like this.
Enjoy your modelling
Francesca
Re: can not obtain modes of vibration in eigenvalue analysis
Posted: Mon Oct 11, 2021 1:42 pm
by liyanwentj
I am sorry that the model did not work after I defined the recorder in the analysis step.
Yes, I have checked your example model. My model has the same analysis steps as the example one. But the result file still has no vibration mode output.
Re: can not obtain modes of vibration in eigenvalue analysis
Posted: Mon Oct 11, 2021 4:27 pm
by LuisB
Hello liyanwentj,
As marafini.f says, the
eigen command does not call the recorder, look at the attached image and check the
custom command that must be added to save the modes of vibration.

- record_customCommand.PNG (27.75 KiB) Viewed 2832 times
Re: can not obtain modes of vibration in eigenvalue analysis
Posted: Tue Oct 12, 2021 12:24 am
by liyanwentj
Thanks, Luis!
It works!
Regards,
liyanwentj
Re: can not obtain modes of vibration in eigenvalue analysis
Posted: Tue Oct 12, 2021 7:28 am
by LuisB
You're welcome!