Problem 4 The Figure shows a shaft simply supported in ball bearings at A and B, and is loaded by a force F that fluctuates between FEmar = 8 kN and Fmin = 0. The shaft is made of AISI 1040 CD steel = 590 MPa) and has a fully corrected endurance (Sut limit Se = 180 MPa. infinite life is predicted, calculate the factor of safety. Estimate the life of the part. If F 200 mm 200 mm Hint: The fatigue strength fraction of Sut at 103 cycles is f = 0.86. 30 mm R2

A rigid coupling with 30 inches of bolt circle diameter transmits a torque of 18,000 lb-in. The coupling material has a yield strength of 90,000 psi.  The coupling is fastened by six bolts.  Assume design factor of  N=3 Calculate the diameter of each bolt.

A coupling GY8 is fixed on a shaft by a type C flat key, as shown in the figure. And the dimensions are also shown in the figure. The torque working on the shaft is 900N-m. [op]=100MPa. Please choose the dimension of the key and check its strength. op 27 = ×10³ kld 1. Note: Standard dimension series of flat key Diameter of shaft d >44-50 Width of key bx Height of key h 14x9 Length of key >75-85 >85-95 22x14 25×14 >50-58 >58-65 >65-75 16x10 18x11 20×12 6, 8, ..., 80, 90, 100, 125, 140, 160, 180, 200... Shaft 140 Coupling 70

(8) An axle (non-rotating) is to be machined from AISI 1144, OQT 1,000°F, to the proportions keyway в shown, with a fillet radius r = 0.2D; F varies 1.SD from 400 lb. to 1,200 lb.; the supports are to the left of B, not shown. Let N = 2 (Soderberg Line). 6" (a) At the fillet, compute D and the 30 maximum tensile stress. (b) Compute D at section B. (c) Specify suitable dimensions. Keeping the given proportions, would a smaller diameter be permissible if the fillet were shot-peened?

Design