Forced Vibration Analysis in Kratos in the frequency domain

[juancamarotti]

Forced Vibration Analysis in Kratos (Frequency Domain)

Hi all!

I am opening this discussion to ask whether Kratos has the capability to perform forced vibration analysis in the frequency domain.

I checked the StructuralMechanicsApplication, and I found a scheme called EigensolverDynamicScheme inside:
eigensolver_dynamic_scheme.hpp.

From my understanding, this scheme solves the free vibration problem:

$$ (-\omega^2 M + K) X = 0 $$

and gives as an output the natural vibration frequencies and mode shapes of the structure.
However, if we now want to solve the forced vibration problem in the frequency domain:

$$ (-\omega^2 M + K) X(\omega) = F(\omega) $$

Question:
Does this scheme support solving the forced vibration problem? If not, is there an alternative approach in Kratos to handle this?

Additionally, since this problem involves an external force $F(\omega)$, we should be able to specify the angular frequency $\omega$ as an input parameter.

Any insights or guidance would be greatly appreciated! 🙌

Thanks in advance for the help! @KratosMultiphysics/structural-mechanics

[loumalouomega]

To my understanding we do not do forced vibration analysis, but as you say it would be relatively simple to do. There are different approches to do it, I would do a custom strategy. Do you need further help?, would you like to contribute those changes to the repository?

[juancamarotti]

Hi Vicente! Thanks for your reply. I was further checking the current custom strategies in theStructuralMechanicsApplication, and I found a strategy called: harmonic_analysis_strategy.hpp
Correct me if I'm wrong, but in my opinion, this strategy is solving the forced vibration problem in the frequency domain.
Would you be able to confirm if this is the case?

[loumalouomega]

I did not developed that stratgey, so let's wait for others @KratosMultiphysics/structural-mechanics to say something