For the part shown in $$ Figure $6-37,$ the $76-$mm diameter end is fir

mly clamped. A force F

is repeatedly applied to deflect the tip until it touches the rigid stop, then released. The part

is machined from AISI $4130$ quenched and tempered to a hardness of approximately $250$

HB$.$ Use Table A$-23$ for material properties. Estimate the fatigue factor of safety based

on achieving infinite life, using each of the following criteria. Compare the results.

Figure $6-37$ The load F is repeatedly applied to push the rod to the stop.

$($a$)$ Goodman

$($b$)$ Morrow

$($c$)$ Gerber