How can I know the values of Fatigue strength coefficient, Fatigue strength exponent, Nc1, FL and SE in Optistruct fatigue analysis? And how to decide value of N in FATSEQ card?

Jay Thakkar

I have already tried to use the eBook given on Altair, however the graph in that and the graph of SN curve used anywhere else is a bit confusing and getting the values using that is a bit confusing. 

1_Sr1.png

event.png

Sn.png

Sr1.png

Adriano Koga_20259

hi,

 

All these parameters comes from your material SN fatigue curve, as shown in the image you shared. If you look at OptiStruct documentation you will find the decsription of these curves. (MATFAT documentation attached).

 

N in FATSEQ is the number of repetitions of your event. This usually is what you're trying to assess. If your structure survives N cycles of your base event.

 

MATFAT.pdf