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Settlement under pullse load (simple model)

Posted: Wed May 20, 2020 3:48 am
by TAHMINANAHAR
Hello,
Could anyone help me, How to solve the problem?
I attached the SCD pre-processor file here.
https://drive.google.com/open?id=1ebGgx ... dhaffplRcc

Re: Settlement under pullse load (simple model)

Posted: Thu May 21, 2020 9:40 am
by akanon
Dear TAHMINANAHAR,

Your model seems okay. I realized the time step that you are using might be too big. Try running the analysis with a smaller step size. It is a fairly small model, so the overall analysis should be fast anyway. I was able to complete the analysis in a few minutes, just by increasing the current time step 10 times.

However, in my opinion, another important problem might cause due to reflecting pressure waves, hitting the bottom and returning, perpetually getting amplified in the model despite the defined rayleigh damping. You can observe this unnatural phenomenon in your model if you record the pressure and watch the contours on a surface plot as time progresses in the post-processor, after completing the analysis by reducing the time step as I did above. Using a vertical dissipating boundary at the bottom of the model might be useful.

To see an example of a Lysmer-Kuhlemeyer boundary in action, please check the dynamic analysis example below through OpenSees Wiki:

https://opensees.berkeley.edu/wiki/inde ... _Analysis)

Finally, you can also attach a model .scd file directly to your message by drag&drop, if only you prefer not to deal with external file-sharing apps in the future.

I hope this helps! Good luck.