Relative displacements during random vibration

[NaikD]

Hi,

I need help regarding test setup for determining relative displacements using accelerometers at two locations during random vibration.

We had done this before about 6 years back but I have forgotten the details.

1. Install two accelerometers at two locations
2. Take output from the two accelerometers to charge amplifier/summer to get the difference
3. Retrieve PSD v/s frequency data and then double integrate to get the relative displacement PSD v/s frequency at the two locations. Then calculate rms displacements.

Is this correct?

Thanks in advance for your help.

Regards,

- NaikD

 

[GregLocock]

Yes, although obviously you need one to point the opposite way if you want the difference, not the sum.

Usual provisos apply, double integration is not straightforward. If you are using B&K 2635 charge amps read the instruction manual it is quite informative on this.



Cheers

Greg Locock


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