Sinusoidal testing with a shaker platform

[NewVibTester]

Hi there,
I am new to vibration testing. I want to test the resonance of a small lightweight object. I have a Controlled Vibration platform shaker:

https://controlledvibration.com/product-item/12-inch-platform-shaker/

And a laser doppler vibrometer to measure the velocity on the platform. I am using Audacity to create a 'chirp' signal to play through the shaker. The limits of the platform are 5 Hz- 2000 Hz. I do not know the resonance frequency of my test objects so I was going to sweep through that range.

Can anyone point me towards resources telling me EXACTLY how to do a sinuoidal test sweep please, in enough detail for someone who is new to the area? At the moment I am concerned about exceeding the limits of the shaker platform and causing damage, given the varying amplitudes at particular frequencies. The material I have read indicates that I need to input a signal with a 'ramp up' below the crossover frequency then with a plateau above that, but I am unsure how exactly to calculate this. Then once I have sorted the signal, I presume I am then just measuring on the object and looking at the waveform to see higher amplitudes- but how can I account for the varied amplitudes of the input signal?

The test does not have to be absolutely perfect but I would like to find the resonant frequencies of the object.

Any help or pointers to useful information would be greatly appreciated.

 

[IRstuff]

Not sure what you are asking. A sine sweep is basically a slow chirp, typically on the order of 1 octave/minute. You don't want it so slow that it essentially dwells on a resonance, only long enough to detect that all the resonances. A much slower sweep or dwell would be used to determine actual the level of the resonance.

TTFN (ta ta for now)
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