Random Vibration Help

[scotland6]

I have a stepped random vibration PSD profile going from 20Hz to 2000Hz (4.2 grms). If I know the mass, stiffness, etc how can I calculate the max acceleration and displacement. I think it uses convolution integrals but I require some help to understand it.

Any help would be appreciated.

Regards

Scotland6

 

[tomirvine]

One approach is the Miles equation, but this equation assumes that the PSD input is constant from zero to infinity Hz.

There is an alternative, general method that allows the PSD input to vary with frequency. The method calculates the transfer function, then multiplies this by the input at each frequency step.

I have a computer program that implements this general method. Please send me an Email if you would like a copy of this program.


Tom Irvine
Email: tomirvine@aol.com

http://www.vibrationdata.com

 

[Tobalcane]

Scotland6
Well some questions, is your profile the control (input) or the response (output)? If it is the control, you need to run a vib so that you can get the response profile at the area that you are concerned with. Once you have the info, a great book to use is "Vibration Analysis for Electrical Equipment" by Dave S. Steinberg published by Wiley Inter-Science (I do vib in the electronic industry). There is a great chapter on Random Vib.

Hope this helps
Tobalcane