Correct option is A
The
S-N curve (Stress vs. Number of Cycles curve) is used to analyze the
fatigue behavior of materials. Fatigue is the failure of a material under repeated or cyclic loading, even if the applied stress is less than the ultimate tensile strength. The S-N curve shows the relationship between the stress amplitude (SSS) and the number of cycles to failure (NNN).
High-stress levels lead to failure in fewer cycles, while low-stress levels result in longer lifespans.
For some materials (like steel), a fatigue limit exists below which the material can endure infinite cycles without failure.
Information Booster:
· Fatigue failure is progressive and occurs without significant plastic deformation.
· It typically starts with crack initiation at stress concentrators.
· Creep relates to deformation under constant stress over time at high temperatures.
· Shear failure occurs due to sliding along planes.
· Impact failure involves sudden loading.
