Accelerometer - G's - Vel - disp
Accelerometer - G's - Vel - disp
(OP)
I am hoping someone can help me with a brain block.
I am collecting accelerometer data in volts. Using the scaling factor we received with the accelerometer (10mV/g), I can get G's. My question is how do I convert to velocity and displacement?
Thanks for your help.
Christopher Quijano
I am collecting accelerometer data in volts. Using the scaling factor we received with the accelerometer (10mV/g), I can get G's. My question is how do I convert to velocity and displacement?
Thanks for your help.
Christopher Quijano





RE: Accelerometer - G's - Vel - disp
You then need to integrate velocity in order to calculate displacement.
The integration can be carried out in either the time domain or the frequency domain.
Highpass filtering is usually needed if the integration is done in the time domain.
Furthermore, the acceleration signal should be multiplied by 386 to convert G to in/sec^2, prior to integration.
Sincerely, Tom Irvine
http://www.vibrationdata.com
RE: Accelerometer - G's - Vel - disp
1. Your instrument should be able to do the integration to velocity and maybe displacement. Beware of double integration to displacement - it adds a lot of noise.
2. To convert a single frequency mathematically use:
V=6.28fD and A=6.28fV where D=displacement in thousants of an inch, V=velocity in inch/sec and A= acceleration in inch/sec-squared. f = frequency in hertz.
RE: Accelerometer - G's - Vel - disp
Obviously integrating your spectra on the FFT analyser will be OK (with certain provisos), if that's what you meant by 'instrument'
Cheers
Greg Locock
RE: Accelerometer - G's - Vel - disp
I ment FFT analyser. I should have said so to prevent confusion. Thanks.
Jim
RE: Accelerometer - G's - Vel - disp
Well, thanks again for your help,
Christopher Quijano
MSA
RE: Accelerometer - G's - Vel - disp
RE: Accelerometer - G's - Vel - disp
I did it after spending substantial time at it.
You wish to know what is the transmissibility of vibration at each frequency within a range of interest. Depends on where your engine is going to be working and how quiet you wish for it to be around it.
RE: Accelerometer - G's - Vel - disp
You may lok into www.reliabilitydirect.com
D=Displacement, P-P,mils
V=Velocity, 0-P,in/sec
A=Acceleration, 0-P,g's
D = 19.10 X 103 X (V/CPM)
D = 70.4 X 106X * (A/CPM2)
V = 52.36 X 10-6 X D X CPM
V = 3.87 X 103 X (A/CPM)
A = 14.2 X 10-9 X D X CPM2
A = 0.27 X 10-3 X V X CPM
RE: Accelerometer - G's - Vel - disp
Another thought... If you have measured the acceleration transmissibility (a dimensionless frequency domain function) won't this be the same as the displacement transmissibility? Or is there something I'm missing? it is late after all!
Regards
Michael
RE: Accelerometer - G's - Vel - disp
(I am not sure that anybody else can integrate back each case the velocity and the displacement! You should know what would be the result!!!)
Also an important point: the frequency range of your accelerometer and a type of your accelerometer! Pleses see the characteristic of your test bench!
We made an another test: A measurement company measured accelerations and in the same points displacements. They gave us the data and we could not fit the datas! I am intereseted in your case, will you get correct data or not!
Ervin
RE: Accelerometer - G's - Vel - disp
For your engine mounts, you want the resonant frequency to be as low as possible to achieve the best isolation. It might be necessary to install travel stops to limit travel during start-up/shutdown, when the engine rotational speed will equal the resonant frequency, but this approach will otherwise give you the best isolation.
RE: Accelerometer - G's - Vel - disp
Thanks in advance,
Roy Gariepy
Maintenance and Reliability Tech
Dorlastan Fibers
Bayer Corp.