MIL-STD 810H Vibration Analysis

[lLouie]

Hi,
There is 4 blades engine which has 180 rad/s. I have to calculate the f0,f1,f2,f3 and f4 values.

For 15 Hz ---> 0.01 g^2/Hz

Blade has 180 rad/s = 28.65*4 Hz = f0
L0 = 0.6 g^2/Hz
S0 in this formula is equal to 3.70

What does -3dB mean?

Actually, I want to understand that f1 is not lower than f0 when I calculate it?
Is there any example for it?

 

[lLouie]

Hi again,

I calculated the Hz and g^2/Hz values. Is that true or not?
I will do fatigue analysis using this, but for which axis should I apply it?