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a dip in Frequency vs Displacement Graph.

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Hey! I am working on a resonator. My resonance frequency is 0.9821 MHz. Why this dip is occurring on resonance frequency?


1 Reply Last Post 6 lug 2016, 10:00 GMT-4
Henrik Sönnerlind COMSOL Employee

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Posted: 8 years ago 6 lug 2016, 10:00 GMT-4
Hi,

The result is imaginary at resonance. You are plotting the real part, which becomes zero.

From the user guide:
---------------
Most results of a frequency domain analysis are complex. In results evaluation, the real value of any result quantity will be shown. Assuming that you want to display for example the displacement in the x-direction, u, you have following options:

- Plot u or real(u). This gives the displacement at zero phase angle.
- Plot imag(u). This gives the displacement at a phase angle of 90 degrees.
- Plot abs(u). This gives the amplitude of the displacement.
- Plot arg(u). This gives the phase angle of the displacement.

---------------

Regards,
Henrik
Hi, The result is imaginary at resonance. You are plotting the real part, which becomes zero. From the user guide: --------------- Most results of a frequency domain analysis are complex. In results evaluation, the real value of any result quantity will be shown. Assuming that you want to display for example the displacement in the x-direction, u, you have following options: - Plot u or real(u). This gives the displacement at zero phase angle. - Plot imag(u). This gives the displacement at a phase angle of 90 degrees. - Plot abs(u). This gives the amplitude of the displacement. - Plot arg(u). This gives the phase angle of the displacement. --------------- Regards, Henrik

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