Hello everyone,

I am doing a simple beam deflection simulation where I want to analyze the fatigue life of my beam. The beam is made of 6061 aluminium alloy and I use 1000N for the deflection force. For my fatigue analysis I use a constant amplitude loading with a sinusoidal curve, which results in R=-1.

It solves just fine but, I was wondering what the "SMax" Output really means (attached image)? It would make sense to me if those where the maximum and minimum stresses, but because I use constant amplitude loading with R=-1, shouldn't they have the exact same absolute value (the minimum just with a negative sign)? Or I am using a too high force, so there are some plastic effects here?

And could I calculate the stress amplitude in this case with (467 MPa - ( - 472 MPa )) / 2?

Thanks a lot in advance,

Linus