For the problem specified in the table, build upon the results of the original problem to obtain a preliminary design of the shaft by performing the following tasks.
(a) Sketch a general shaft layout, including means to locate the components and to transmit the torque. Estimates for the component widths are acceptable at this point.
(b) Specify a suitable material for the shaft.
(c) Determine critical diameters of the shaft based on infinite fatigue life with a design factor of 1.5. Check for yielding.
(d) Make any other dimensional decisions necessary to specify all diameters and axial dimensions. Sketch the shaft to scale, showing all proposed dimensions.
(e) Check the deflections at the gears, and the slopes at the gears and the bearings for satisfaction of the recommended limits in Table 7€“2. Assume the deflections for any pulleys are not likely to be critical. If any of the deflections exceed the recommended limits, make appropriate changes to bring them all within the limits.
Problem 3-68, A countershaft carrying two V-belt pulleys is shown in the figure. Pulley A receives power from a motor through a belt with the belt tensions shown. The power is transmitted through the shaft and delivered to the belt on pulley B. Assume the belt tension on the loose side at B is 15 percent of the tension on the tight side.
(a) Determine the tensions in the belt on pulley B, assuming the shaft is running at a constant speed.
(b) Find the magnitudes of the bearing reaction forces, assuming the bearings act as simple supports.
(c) Draw shear-force and bending-moment diagrams for the shaft. If needed, make one set for the horizontal plane and another set for the vertical plane.
(d) At the point of maximum bending moment, determine the bending stress and the torsional shear stress.

(e) At the point of maximum bending moment, determine the principal stresses and the maximum shearstress.

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トho 10 in 18 in 12 in T2 500 lbf T, 75 lbf 8-in dia. 1 ½-in dia. 10-in dia.