Question

A critical component of a machine is subject to cyclic loading which produces a bending moment and stresses that cycle from "0" to a maximum bending stress.

The material is steel having a hardness of 160 BHN, Su = 551 Mpa and Sy = 213 Mpa

The cross sectional dimensions of the material has a width of 20 mm and a height of 25 mm. The geometry of the part transitions to a larger section through a fillet which has been estimated to have a stress concentration factor of Kt = 1.87 and a notch sensitivity factor of q = 1.87.

The infinite fatigue strength Sn has been calculated at 182.83 Mpa.

Calculate the maximum bending moment that would give infinite fatigue life with a SF = 1. Support your answer by drawing the Goodman's Diagram.

Answer 1