COMSOL : damped vibration analysis of a cantilevered beam

[incensus]

Hi..
I'm trying to do the damped vibration analysis of a cantilevered beam. Although i am choosing no damping in subdomain settings menu, it solves the problem as if the material is damped (the result is a damped vibration signal).
Is this is a bug or am i missing something?
Thanks in advance

[Nick Bruno]

It must be taking the stiffness of the beam into consideration. I believe the damping option is for a specific type of damping ( modeling wise ) You can probably find out more on the damping option from the modeling guide.

The initial conditions probably play a role as well. Is there an initial displacement, or a wave input?

[incensus]

Hi Nick;
There are two damping options : No damping and Rayleigh damping.. I choose "no damping". I know that Rayleigh damping is the combination of mass and stiffness but i dont choose it.

There is no initial displacement or any wave input. Only a force input(which is almost a impulse function) on one of the free boundaries.

There is another interesting point that if i choose "Weak Constraints : OFF", the results become very 'absurd'.