$-------$C D E F G$------------$

The rotating shaft shown in the figure is machined from AISI $1020$ CD steel. It is subjected to

the force of F$=6$kN and working in an environment of $50^($@$)$C with a reliability of $99\mathrm{.}9\%$

Determine;

a$)$ the endurance limit S$\_($e$)\text{'}$ and modified endurance limit S$\_($e$)$ using Marine Factors

b$)$ the notch sensitivity q and fatigue stress$-$concentration factor K$\_($f$)$ at the fillet

c$)$ the reversing bending stress sigma$\_($r$)$ at the fillet drawing bending moment diagram of shaft;

d$)$ if the result is in finite$-$life region or in infinite$-$life region

e$)$ the fatigue life in cycles

f$)$ the fatigue strength at $10^(5)$ cycles

g$)$ the factor of safety applying the criteria

a$.$ modified Goodman

b$.$ ASME$-$elliptic