Three identical fatigue specimens (denoted A, B, and C) are fabricated from a nonferrous alloy. Each is subjected to one of the maximum–minimum stress cycles listed in the following table; the frequency is the same for all three tests. Specimen
A
B
C
​σ
max
​(MPa)
+450
+300
+500
σ
min
​(MPa)
-150
-300
-200
(a) Rank the fatigue lifetimes of these three specimens from the longest to the shortest.
(b) Now, justify this ranking using a schematic S-N plot.