how to calculate fatigue life

[rikcardo]

Hello

How can I calculate the fatigue life of a variable stress between 0 and 90 MPa in cast aluminum?

Do I use the mean stress and compare it with the wohler curve? what is the logic of using the mean stress? Why not the maximum stress?

Do I have to use the Goodman or Gerber diagram?

Any advise on literature or websites about this topic?

Thank you in advance

[edgepflow]

Try the Soderberg Line. See Equation 50.31, "Mechanical Engineering Reference Manual for the PE," 10th Edition.