Discussion Forum

April 27, 2012 1:31pm UTC in response to Ulrika Lundholm

Re: Stress/vibration analysis

Hi

A frequency domain analysis applies a Force load (that you have forgotten to define) as an amplitude mutliplied by a constant sinus type excitation at a frequency range you define.

The second effect is that you have resonaces around 25 kHz and you are plotting the respons around 100 Hz, you will see nothing so far away from your resonance.

I would propose:
1) perform a eigenfrequency to get the modes
2) start with frequency domain (then later go to frequency - modal) for a frequency range ot +/- 5% around your first resonance
3) define a load, i.e. a body gravity load Fy=g_const*solid.rho

then run

Another point to consider: damping, without any damping the resoance are so sharp that often COMSOL either skip then or fail to pass the resonance

To get back to your frequency-domain modal :

Do not forget: !!!!
you need to right click the body or boundary load and add a "Harmonic perturbation" tick this will add the "tilda" on the icon and your load will now be correctly set up .

--
Good luck
Ivar

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