Phase of the Frequency Response Function - FRF - Vibration
Phase of the Frequency Response Function - FRF - Vibration
(OP)
Hi
I have difficulty to interpret the phase angle from my frf. I would appreciate if anyone can help me with this issue.
Attached is my FRF plot. Is it correct? and why is it noisy?
If the phase at any peak changes from -180 to 180 (not 90 degrees), is it then related to the natural frequency?
Thanks alot,

I have difficulty to interpret the phase angle from my frf. I would appreciate if anyone can help me with this issue.
Attached is my FRF plot. Is it correct? and why is it noisy?
If the phase at any peak changes from -180 to 180 (not 90 degrees), is it then related to the natural frequency?
Thanks alot,

RE: Phase of the Frequency Response Function - FRF - Vibration
It is 'noisy' around 20 hz because there's no signal there.
Cheers
Greg Locock
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RE: Phase of the Frequency Response Function - FRF - Vibration
https://community.sw.siemens.com/s/article/what-is...
Walt
RE: Phase of the Frequency Response Function - FRF - Vibration
2. by the way there is a danger in equating "amplitude" with FFT magnitude.
RE: Phase of the Frequency Response Function - FRF - Vibration
look at higest peak, where you have enough energy to calulate correctly phase.
Seems #2 resonance 12 and 37 Hz aprox. In 12Hz it is clear the change phase shift with 90degrees at resonant frequency.
In order to well understand if your measurement is correct it is usefull to use choerence function.