the model does not work properly

[jpereirasan]

Dear STKO Team.

I am performing a 2D dynamic nonlinear geotechnical analysis of a slope. (what I want is apply a shake to a saturated soil that is constrained at the base (x-y) and at the sides (y) and has a load at the top edge).

STKO has allowed me to correctly model the problem but the results do not correspond to the expected (the generation of pore pressures p of the U-P elements is quite strange and the model continues to move after the seismic motion is applied).

I would like if possible someone from the STKO team could check the model and see if there is something with respect to the nonlinear analysis specifically in the analysis command that is incorrect and that is why it is not working correctly, or if there is some other problem that is affecting the model.

Best regards.

[jpereirasan]

I updated the model and was able to correct the static analysis, I changed the way of applying the dynamic load and now I use UniformExcitation, however the model continues with a displacement after applying the load.
I hope you can help me to revise the model.

[STKO Team]

Maybe it's the horizontal displacement due to gravity load, or some plastic deformation?

[jpereirasan]

Is it possible to start the dynamic analysis with 0 initial displacements due to gravity? How can i model that in STKO/OpenSees, is it with a command like initialStateAnalysis ?

[kesavapraba]

Why don't you subtract the initial displacement from the graph and interpret the results? You have the option "loadConst" enabled before conducting the dynamic analysis; you can disable it. But, you will miss the gravity load effect from being carried forward to the subsequent dynamic analysis if you do not enable loadConst option. Are you sure you want to do that?

[jpereirasan]

Thanks Mr. Kesavan for your repply.

That is what i'm want to do

'' 1) Gravity was applied to activate the initial static state with: …. At the end of this step, the static soil state was imposed and displacements under own-weight application were re-set to zero using the OpenSees command InitialStateAnalysis. ''

I want to reset to zero the displacement due to the own weight application.

Here is my model, i corrected some mistakes but i don't know how to continue to model what i explained above.

[STKO Team]

You correctly used the custom commands initialStateAnalysis on and off, but you forgot to wrap your PDMY material inside an InitialStateAnalysisWrapper.
Here's the working file:

modelstkoforum5.zip

(145 KiB) Downloaded 143 times

InitWrapper.png (127.98 KiB) Viewed 846 times