Undertandstanding FFT Plot

[AndrewUK]

I’ve been doing some tests on a set-up at work, vibration is not my area of expertise but I’m keen to develop it so any ideas are welcome.

The set up is a thin plate restraint on all edges, the plate as small holes drill in it (0.2mm dia, by 0.2mm deep [blind holes]). I’m vibrating the plate to remove
Air bubbles when it is submerged in a tank of plating liquid.

As far as work is concerned the problems fixed but for myself I’m left wondering. Any info on this would great.

manged to get FFT on my site here

http://www.andrewflower.plus.com/scan.jpg

The peak with the dot is 65 Hz the peak to the left of that is 54Hz.

Can anyone help make sense of the plot? If 54Hz is fundemental freq, what is 65 Hz?

as post in vibration forum but you guys seem to deal with FFT more. thread384-150916

 

[rkn40]

Without more details, I can only guess the first peak is the first harmonic, second peak is the second harmonic and so on..
Look into these resources to understand more about fft

1.

http://www.feadomain.com/download.php?view.27

2.

http://www.feadomain.com/download.php?view.26

3.

http://www.feadomain.com/download.php?view.25

4.

http://www.feadomain.com/download.php?view.55

(this is an excel spread sheet which lets you create wave forms to understand Fourier trnasforms etc)