Question

 In the figure below, a rotating shaft (for speed reducing gearbox) is subjected to radial forces at A= 400 lbr .and at C = 800 Ibr. These radial forces are caused by spur gears mounted to shaft (a result of the pressure angle of the teeth, 20 degrees) that mesh with 2 other spur gears, not shown. Also, The shaft transmits a constant torque of 11110 in-lbr (925 ft-lbr) due to the tangential force (Wt: transmitted load) at C of 2222 Ibr (NOTE: there is bending in two planes). The shaft is supported by cylindrical roller bearings at B and D. The shaft is machined from AISI 4130 Q&T 1200 deg. F steel.

 1) Find Se , Sy, and Su.

 2) Using Matlab or EXCEL plot the modified Goodman line (fatigue failure criteria).

 3) Using Von-Mises stresses σ', plot the load line (on same plot as part 2 above) and determine σ'a and σ'm allowable (using modified Goodman line) if the fatigue factor of safety nr=2 (infinite life).

 4) What are Sa and Sm using modified Goodman criteria? (the intersection of load line and Goodman line)

 5) Determine the required shaft diameter for strength and infinite life criteria (Goodman). Note: the stress concentrations at two locations: the two keyways at each spur gear. Assume

 the stress concentration factors to be: K= 1.7 for bending and K=2 for torsion.

Answer 1

Thank you...