Learning Forum

[Michael Fusaro]

I have a question about fatigue as it relates to the ANSYS Random vibration module.

If you are using a PSG G Acceleration excitation for the vibration, can that be considered an R= -1 fatigue cycle (i.e. 'fully reversed'?)

I would think a sinusodial vibration input would have a mean centered around zero but I am not sure.

 

Thanks in advance,

Michael 

[danielshaw]

The concept of R-Ratio is not applicable to random vibration loading.  You are not cycling the a load between values.  Yes, a fatigue analysis for harmonic loading would typically assume that the sinusodial loading is centered about zero. That assumption is built into the Mechanical Fatigue Tool.