Learning Forum

[Samuele Luigetti]

hello everybody

i'm doing harmonic response of a structure. I set a constant structural damping coefficient, but appears the message "the system is solved without damping", and i do not understand why since there is damping in effect.

[Erik Kostson]

Hi

As long as you can see the effect of damping in the results (reduced peaks around resonance) and that it is different compared to without damping, that is the most important (the warning message can then be neglected).

All the best

Erik

[Samuele Luigetti]

ok thanks but why it appears?

[peteroznewman]

Was the Harmonic Response a stand alone analysis or was there an upstream Modal analysis Solution cell linked to the setup cell of the Harmonic Response creating a MSUP Harmonic Response analysis?

Do you have any elements such as springs or bushings in the model that included damping?

[Samuele Luigetti]

Hi peter, it's MSUP analysis, not stand-alone. I have springs, but without damping, only with stiffness.

[peteroznewman]

What version of Ansys are you running?

In Ansys 2019, Structural Damping was not supported for MSUP Harmonic Response.

In Ansys 2022, Structural Damping is supported for MSUP Harmonic Response.

[Samuele Luigetti]

2022 r1

[peteroznewman]

So in 2019 in a MSUP Harmonic Response, there was some code to warn you that if Constant Structural Damping was the only damping then the warning message was "system is solved without damping".

Then in 2022, they support Constant Structural Damping. Is it possible that they forgot to delete the code that issues the warning message?  Maybe.

I like Erik's suggestion, solve once with 0.0 Structural Damping and solve again with a 0.1 Structural Damping and see if the magnitude of the peak response is reduced.

[Samuele Luigetti]

yes i tried two different coefficient and the response is different, so the damping is on