fatigue analysis result view

Mani kumar_21615

Hi, 

 

  In fatigue analysis post processing what we need to check usually Damage or Life or Both.

 

In my simulation Damage is 0.05.

And Life varies from 54 to 10e6. What does it mean by 54 in life?Is this 54 associated with damage or not?

 

PrasannaK

Hi Mani,

 

Life is 1/Damage. Here we need both life and damage results. 

Life varies from 54 to 10e6 means minimum life of all elements is found to be 54 cycles and maximum life is 10e6 which is infinite. 

So 54 in life means it can withstand 54 cycle of alternating force before the element fails.

 

Thank You

Mani kumar_21615

I have done Vibration fatigue analysis, output of frf analysis are input of Fatigue analysis.

 

i have given sweep rate in oct per min(in FATLOAD) for fatigue analysis..

 

My requirement  is the part should with stand for 3 hours(i.e 180 min)

 

In out put results what does it mean by life? No.of cycles/minutes/hours?

 

If life is in  No.of cycles How we can say the whether the part with stand for 3 Hours or not?

 

I think that 54 is 54 minutes? Am i right?

 

Rex_22369

Altair Forum User said:

I have done Vibration fatigue analysis, output of frf analysis are input of Fatigue analysis.

 

i have given sweep rate in oct per min(in FATLOAD) for fatigue analysis..

 

My requirement  is the part should with stand for 3 hours(i.e 180 min)

 

In out put results what does it mean by life? No.of cycles/minutes/hours?

 

If life is in  No.of cycles How we can say the whether the part with stand for 3 Hours or not?

 

I think that 54 is 54 minutes? Am i right? 

 

Hello Mani,

 

The cycle result is not time, it tells how many cycles the part can resist.....

 

In the Optistruct User Guide, page like 307 shows you how to calculate the cycles on the elements, but the way how Optistruct works is not clearly explain here, I asked in the past, but still no feedback.

 

 In the fatigue simulation, due to the material S-N curve, the vibration cycles is needed instead of time, even your input is in time, but finally software will calculate the cycles anyway.

 

Try to read the USER GUIDE, it should be helpful!