Defining S-N curves

[rachins.stha]

Hello, 

I' m  also new  user of auto-desk cad-in Nastran. My question is should we modified Se ( fatigue strength ) for elevated mean stress? ( According to theory, if the stress isn't fully reversed , we have to modified Se (reduced)  according to soderberg or goodman criteria,)  

[John_Holtz · Accepted solution]

Hi @rachins.stha 

The procedure that I am familiar with, and the approach used by Autodesk Nastran, is to adjust the calculated alternating stress Sa to account for the mean stress Sm. The endurance limit Se is a material property and is not changed by the calculated results.

[rachins.stha]

Dear sir,

Thank you for your clarification.