Hello, 

Can anybody help finding the equation used for calculating fatigue life cycle in solid works simulation? In theoretical analysis, we know that below equation is used where stress is an equivalent reversible stress calculated by using Modified Good-man criteria and a, b can be determined by applying boundary condition. Here are the equations which are used for theoretical analysis. 

Power function

Goodman equation to calculate equivalent reversible stress from alternating and mean stress component at the condition of R=0.  

Earlier maximum bending stress was calculated from below equation. fatigue stress concentration factor along with notch sensitivity factor was also applied. P is load, b= gage width, d=specimen thickness, L=gage length of a Krouse-type specimen. 

During FEA simulation, the ASME carbon steel curve for R=0 was selected and mean stress correction factor was applied in the properties as Goodman. Computing alternating stress using equivalent Von mises stress was also checked.

In my mind, I have tried to ensure that everything in FEA simulation aligns with the theoretical analysis. However, I could not identify which equation is being used for calculating life cycle in simulation interface so that I could be 100% certain of the consistency.

It would be appreciated, if you can share any thoughts, ideas or material to justify the issues. Thank you