GATE MT 2019 Q23. The S-N curve of steel is given below. If the stress ratio, sigma(min)/sigma( max)= -0.8, the maximum stress (in MPa rounded off to nearest integer) that the steel can withstand for infinite fatigue life is _______.

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See lessThis answer was edited.From the given S-N curve we can see that at 300 MPa the curve becomes flat i.e. stree is constant with number of cycles. This is known as the fatigue limit or endurance limit. At(Below) this stress amplitude the material will have infinite life i.e. increasing number of cycles won't effect the fatigRead more

From the given S-N curve we can see that at 300 MPa the curve becomes flat i.e. stree is constant with number of cycles. This is known as the fatigue limit or endurance limit. At(Below) this stress amplitude the material will have infinite life i.e. increasing number of cycles won’t effect the fatigue properties. Based on this the problem can be solved as :

See lessCorrect answer is in the range of 330-335. @Rohit.km described it best. Thank you.

Correct answer is in the range of 330-335. Rohit jha.km described it best. Thank you.

σmin /σmax = -0.8 and( σmax - σmin )/2 = 300 from which σmax = 333.33 MPa

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See less_{min}/σ_{max }= -0.8 and( σ_{max }– σ_{min })/2 = 300 from which σ_{max = 333.33 MPa}