BeamContact3D vs BeamContact3Dp

[bibloo]

Hello,

I want to take into account the gap formation between the pile and the soil and I was wondering which element I should proceed with.

I read that BeamContact3D uses Lagrange multiplier nodes whereas BeamContact3Dp uses a penalty value. However, while defining BeamContact3D we also provide gap and force tolerances. That's not the case in the penalty (BeamContact3Dp) approach.

I tried to implement both of them but had problems with both.

My model with BeamContact3D implemented stuck during the stage 3 analysis, and it never gives any error or completes the first iteration. I suspect it never converges. I also tried to play with constraints but there is no luck yet. I am doing a Transient analysis and using Newark integrator.

The model with BeamContact3Dp element converges without any error but no matter how much load I applied the recorded forces and friction forces are too small (almost zero). I run the eigenvalue analysis and structural periods makes sense. However, there is no friction developing on the contact surface.

I didn't use the STKO preprocessor but this forum is the only source that I could find info about BeamContact3D and BeamContact3Dp elements. I would really appreciate it if STKO Team could share their valuable ideas with me.

[STKO Team]

Without an STKO pre-processor file we cannot find the issue. However here are some advices:

Working with those 2 elements is not easy.
Make sure the slave node (solid) is not above or below the 2 beam's end-nodes. If it's not true, the slave node will not find contact

with the penalty version (BeamContact3Dp) pay attention to the penalty stiffness. It should be high enough but not too high.
We also gave a webinar on a new contact element we developed for OpenSees.
https://www.youtube.com/watch?v=tXA5guozrFU