Split a random vibration spectrum by 2 - HOW ?
Split a random vibration spectrum by 2 - HOW ?
(OP)
Hi all,
Im new on this forum and I hope you will be able to help me :D
I have an equipment to shake from 5Hz to 150Hz and my shaker is too smooth for very low frequencies (from 5Hz to 10Hz)=> overtravel. I would like to use another test equipment (like jack) in order to test from 5Hz to 10Hz and my shaker from 10Hz to 150Hz.
Is it possible to split my vibration spectrum by 2 (from 5 to 10Hz on a specific test equipment and from 10 to 150Hz on my existing shaker) and keep the same energy or fatigue on the equipment tested ? Does a specific law exist ?
I can precise if it s not clear to you (Im French and my english is sometimes "poor" compared to you :D)
Hope you will have some ideas for me !!
Julien
Im new on this forum and I hope you will be able to help me :D
I have an equipment to shake from 5Hz to 150Hz and my shaker is too smooth for very low frequencies (from 5Hz to 10Hz)=> overtravel. I would like to use another test equipment (like jack) in order to test from 5Hz to 10Hz and my shaker from 10Hz to 150Hz.
Is it possible to split my vibration spectrum by 2 (from 5 to 10Hz on a specific test equipment and from 10 to 150Hz on my existing shaker) and keep the same energy or fatigue on the equipment tested ? Does a specific law exist ?
I can precise if it s not clear to you (Im French and my english is sometimes "poor" compared to you :D)
Hope you will have some ideas for me !!
Julien





RE: Split a random vibration spectrum by 2 - HOW ?
RE: Split a random vibration spectrum by 2 - HOW ?
I m looking for the theory which is introducing such calculation... what is uneasy !
RE: Split a random vibration spectrum by 2 - HOW ?
My point is that the amplitude and phase of a linear transfer function can be determined point by point (i.e. frequency by frequency) or all together. You are choosing to do it in two measurements.
RE: Split a random vibration spectrum by 2 - HOW ?
For example, if the PSD is 0.1g²/Hz during 1hour from 5Hz to 150Hz, what would be the duration of excitation t1 (with I assume 0,1g²/Hz) and the duration of excitation t2 with I assume 0,1g²/Hz).
I dont think that it is linear and using transfer functions seems to be a little complicated because I m not sure that I can determinate it (What i have never done before)
Thanks for your support whatever :D !!
RE: Split a random vibration spectrum by 2 - HOW ?
If you are using swept sine then yes you can, but I get the impression you are using random.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Split a random vibration spectrum by 2 - HOW ?
If someone have any information please advice, perhaps we will find on this forum a vibration genious !! (hope so :D)
Whatever thanks to all, sure I ll be back to help or to ask for help in future !!
See U
Julien