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Hello team STKO,

I am simulating a single pile-soil centrifuge test carried out by Gohl (1991) for validation purpose. I have tried both 2D and 3D models and here are a few doubts regarding the problems I am facing.

1. In 2D model, I cannot use beam-to-solid-coupling right? Because it is made for 3D models only if I am not wrong. Now for 2D, I am left with only two options. Either I have to use edof or contact elements. I don't want to use contacts right now as it will make the analysis complicated. Also, edof cannot predict the real scenario and the pile BMs cannot be observed. So, can you please suggest some alternative to this?

2. To use beam-to-solid coupling I have modelled a 3D soil-pile model. But when the automated absorbing boundaries (ABs) are used, I get an error "cannot find initial permutation". Then from the forum, I came to know that it is some kind of distortion issue and you are trying to improve it. So, I would like to know if the problem is already sorted out.

3. Also, it was mentioned that if the standard AB elements are used, there should not be any problem. So, I tried with those elements. But, my analysis is not running, neither it is showing any error.

4. Again, I have learned in this forum to create dummy nodes by drawing lines (in 2D) and faces (in 3D) and not assigning any physical or element properties to those lines and faces. I have used this technique to connect pile-soil by creating rigid links and edofs (same as the 3D beam-to-solid-coupling) in my 2D model. But, I was unsuccessful again.

Therefore, I request you to help me in this regard. I will be sending four .scd files in the sequence of the points I have mentioned here. I will send the files through email as I do not want to make my files public. Thanking you in anticipation.

Regards,
Begum Emte

Dear STKO team,

Please reply to my queries.

1. In 2D model, I cannot use beam-to-solid-coupling right? Because it is made for 3D models only if I am not wrong. Now for 2D, I am left with only two options. Either I have to use edof or contact elements. I don't want to use contacts right now as it will make the analysis complicated. Also, edof cannot predict the real scenario and the pile BMs cannot be observed. So, can you please suggest some alternative to this?

You're right, that automation works only in 3D, but your suggested alternative ...

4. Again, I have learned in this forum to create dummy nodes by drawing lines (in 2D) and faces (in 3D) and not assigning any physical or element properties to those lines and faces. I have used this technique to connect pile-soil by creating rigid links and edofs (same as the 3D beam-to-solid-coupling) in my 2D model. But, I was unsuccessful again.

... should work

2. To use beam-to-solid coupling I have modeled a 3D soil-pile model. But when the automated absorbing boundaries (ABs) are used, I get an error "cannot find initial permutation". Then from the forum, I came to know that it is some kind of distortion issue and you are trying to improve it. So, I would like to know if the problem is already sorted out.

The problem can be solved only by trying to make a more regular mesh. Otherwise, you should manually create 3D layers outside of your soil domain, as shown in the first webinar about absorbing boundaries.

Try to send your files here: [email protected]

Thank you for your reply. I have sent the files to the mentioned email ID. I request you kindly look into the files.