Question

Suppose that the fatigue data shown in the animated figure is for a steel alloy that was tested using bending-rotating tests. A rod of this alloy is to be used for an automobile axle that rotates at an average rotational velocity of 900 revolutions per minute. Give the maximum lifetimes of continuous driving that are allowable for the following stress levels: (a) 450 MPa hours 0.369 (b) 380 MPa hours 3.13 (c) 310 MPa hours 20.8

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Answer 1

- For a stsess I of USO Mpa. me is 18.000 cycles (log Nf ч.as) 0.37S hr For a stress level of 380 Mpa ftie lifetime isa @sxos yle) C lag Nf= s.is) t For a stress level of ato MPa fodt For a stress leuel o ato Mna ftige ife time opp is IS imin 83 hr