Problem 3: A proposed shaft design for problem 2 is shown below. The material is 1018 cold-drawn steel (SUT = 64 kpsi) and the desired reliability is 95%. The gear centers

for force transmission are shown and the gears sit against the shoulders. All units are in inches. Gear center 0.5 1.00 1.3 16 15 17 1.75 14 2.5 14 1.75 1.3 11 Gear center 1.00 → a. Using pen/paper determine the minimum safety factor along the shaft using the Goodma failure criteria. b. In Matlab, plot the safety factor along the length of the shaft. c. Using your knowledge of safety factor scaling, and intuition from Matlab: describe a suitable geometric dimension of the shaft that is important for determining the safety factor (there may be more than one). Describe how changes in this dimension would change the safety factor. d. Locate a suitable stock-material on the McMaster-Carr website that can be used to machine this shaft with desired tolerance of ±0.001 inch.