Contact elements and transient analysis

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miran
Posts: 42
Joined: Wed Apr 29, 2020 7:15 pm

Contact elements and transient analysis

Post by miran » Tue Dec 13, 2022 12:19 pm

Hi,

I am trying to perform a dynamic analysis using the new contact element in STKO. My model performs great for static loading, but not so great for dynamic loading. The solution converges, but the results are either way off or very noisy. It seems to work best with Krylow-Newton as the solver and TRBDF2 as the integrator.

Is there anything in particular I should be aware of regarding this element with respect to transient analysis? I have attached the file
pile_soil.zip
(2.56 MiB) Downloaded 238 times
.

PS! I am not using correct boundary conditions for this model as I just want to transient analysis to work for now.
Regards,

Miran Cemalovic
PhD Candidate
Department of Structural Engineering
Norwegian University of Science and Technology (NTNU)
NO-7491 Trondheim, Norway
https://www.ntnu.edu/employees/mirancem

STKO Team
Posts: 3066
Joined: Tue Oct 29, 2019 8:45 am

Re: Contact elements and transient analysis

Post by STKO Team » Wed Dec 14, 2022 5:52 pm

1) the local axes -Z is not assigned to the bottom-contact interaction, so the column foot will not be in contact.
Try to see if that is the source of the issue.

2) It may happen that due to the penalty stiffness of the (many) contact elements, you will have some issues in dynamic analysis. Try to use an integrator that introduced numerical damping, such as Hilber-Hughes-Taylor with alpha = (0.67 for maximum damping)

miran
Posts: 42
Joined: Wed Apr 29, 2020 7:15 pm

Re: Contact elements and transient analysis

Post by miran » Fri Dec 16, 2022 3:28 pm

Thank you for the quick reply, Hilber-Hughes-Taylor did the trick!
Regards,

Miran Cemalovic
PhD Candidate
Department of Structural Engineering
Norwegian University of Science and Technology (NTNU)
NO-7491 Trondheim, Norway
https://www.ntnu.edu/employees/mirancem

STKO Team
Posts: 3066
Joined: Tue Oct 29, 2019 8:45 am

Re: Contact elements and transient analysis

Post by STKO Team » Mon Dec 19, 2022 8:18 am

You're welcome

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