Interpreting Vibration Measurement Results
Interpreting Vibration Measurement Results
(OP)
Hi all,
I am having trouble with an experiment I am conducting at the minute. I am designing a device to be mounted on a vibrating structure and am trying to determine a damping mechanism to eliminate the vibration on the imposed product. I have measured the vibration on the structure it is to be mounted on with the output measured in volts. I want to convert this to dB and am using the formula 20*Log(Vout/Vref) however what am I supposed to take as the Vref, is it 10^-3, as the charge amplification on the charge amplifier was at 10mV, or could anybody help me on this. Also how do I modify the dB reading to a displacement, velocity etc. in order to determine damping factor value?
Cheers P.
I am having trouble with an experiment I am conducting at the minute. I am designing a device to be mounted on a vibrating structure and am trying to determine a damping mechanism to eliminate the vibration on the imposed product. I have measured the vibration on the structure it is to be mounted on with the output measured in volts. I want to convert this to dB and am using the formula 20*Log(Vout/Vref) however what am I supposed to take as the Vref, is it 10^-3, as the charge amplification on the charge amplifier was at 10mV, or could anybody help me on this. Also how do I modify the dB reading to a displacement, velocity etc. in order to determine damping factor value?
Cheers P.





RE: Interpreting Vibration Measurement Results
To convert to displacement etc you need to use integration, which is very easy in the frequency domain.
Cheers
Greg Locock
I rarely exceed 1.79 x 10^12 furlongs per fortnight
RE: Interpreting Vibration Measurement Results
I have read that once it is in dB that all my results are referred back to the reference level once it is stated however I need to convert these results to a fixed unit of measurement in order to determine a sufficient damping mechanism for my device.
P
RE: Interpreting Vibration Measurement Results
Personally if I am just looking at vibration I default to m/s/s, it is rare to need so much dynamic range that dB are necessary and people just get confused.
If it is less than 0.1 m/s/s don't worry about it, if it is more than 50 things will break.
Cheers
Greg Locock
I rarely exceed 1.79 x 10^12 furlongs per fortnight