Mechanical Behaviour of Materials · Fatigue · 2 marks · Numerical answer
The steel S–N curve shown has an endurance stress amplitude of 300 MPa. With stress ratio σmin/σmax=−0.8, find maximum stress for infinite fatigue life in MPa (nearest integer).
Stress amplitude is $\sigma_a=(\sigma_{max}-\sigma_{min})/2=\sigma_{max}(1-R)/2$. With R=−0.8 and the plotted endurance amplitude 300 MPa, $\sigma_{max}=2(300)/1.8=333.3$ MPa, or 333. This uses the given S–N curve without an additional mean-stress correction.
More Fatigue questions
GATE 2024 MT Q54– A steel bar has ultimate tensile strength 1000 MPa and fully reversed fatigue limit 250…
GATE 2023 MT Q27– Which of the following is/are responsible for reducing the high cycle fatigue life of a…
GATE 2023 MT Q64– A specimen has maximum initial surface-crack size 1.5 mm and cyclic stresses max=300 MPa,…
GATE 2022 MT Q52– An alloy has the following high-cycle fatigue data for alternating stress a: Stress (MPa)…
GATE 2020 MT Q62– A fatigue specimen has constant-amplitude cyclic stress and zero mean stress, with da/dN(…
GATE 2019 MT Q28– Beach marks are commonly observed on a metal fracture surface after which test?
