GATE 2024 MT – Question 54
A steel bar has ultimate tensile strength 1000 MPa and fully reversed fatigue limit 250 MPa. By the Goodman relation, its fatigue limit at tensile mean stress 100 MPa is ______ MPa (nearest integer).
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Correct answer: 225 to 225
Explanation
Goodman’s relation is $\sigma_a/S_e+\sigma_m/S_u=1$.
Thus $\sigma_a=250(1-100/1000)=\boxed{225\ \mathrm{MPa}}$.
The tensile mean stress lowers the allowable stress amplitude.