ERROR: the analysis did not converge

[Freedom]

Dear experts，
I encountered problems while using STKO to analysis. According to the 'sfsi' model in the teaching, I changed the soil material to PDMY and established the sand-pile interaction model. My analysis step is almost exactly the same as the teaching model 'sfsi', but there is a non-convergence problem in the first step of static analysis. After many attempts to modify, I still can 't solve this error. I don 't know the reason for this error. Attached here my model attachment for your reference. I would highly appreciate any help in rectifying this error. Thank you for any help in this regard.

Look forward to your reply!

[kesavapraba]

Hi, We are unable to understand what teaching material you referred to, so can you please provide us with the webinar's link that you mentioned? Thank you.

[Freedom]

This model has no teaching video, only a '.scd' file. This is the correct original model attachment for your reference!

[kesavapraba]

Hi, the first stage of the analysis runs successfully on my PC - I used 10 increments. You can first try to use "Adaptive Time Step" in the analysis settings, as shown in the picture. Additionally, you can also try to play around with other analysis settings.
Please also ensure that you are using recent versions of STKO (3.3.0) and OpenSees solvers (3.4).

[Freedom]

Are you running the 'sfsi' file or the 'model' file? I can 't run the 'model' file, I don 't know why there will be soil acceleration in the static analysis stage. Can you help me solve the 'model.scd' file problem? I will be grateful.

[Freedom]

I also change the analysis steps as you mentioned, but the 'model' file still can't run. Can you tell me the reason?

[STKO Team]

There are some mistakes:

• The solids in the Hole do not have an Element/Physical Property -> Singular matrix -> I applied the proper element/physical property
• UP elements must be used with transient analysis only: I converted the static steps into quasi-static dynamic steps (large duration = 100 seconds)
• For the point above, I had to scale the Linear timeSeries by a factor of 1.0-2, so that at time 100 seconds it applies the 100% of the load
• The model is large so I used a norm Type = 0 (in the test command)

Try this:

jianhua_4_analysis_3.zip

(854.97 KiB) Downloaded 464 times

Also make sure you don't need any BC on Pressure DOFs