Answer:
≈ 41.95 Kpsi
Explanation:
Note : We can Obtain parameters of Marin surface modification factor from Table 6-2
Given data:
Diameter of rod ( d ) = 3 inches
Tensile strength( Sut ) = 150 kpsi
Calculate the endurance strength
endurance strength ( Se ) = Ka*Kb*Kc*Kd *Ke*Kf * Se' -------- ( 1 )
Ka = aSut^b = ( 2.7 ) 150^-0.265 = 0.7157
Kb = 0.879 ( d )^0.107 = 0.879 ( 3 )^-0.107 = 0.7815
Kc, Kd , Ke , Kf = 1 , 1 , 1 , 1
Se' = 0.5 * 150 = 75
Back to equation 1
Se = 0.7157 * 0.7815 * 1 * -------- * 75
≈ 41.95 Kpsi
