3.7-5 The propeller shaft of a large ship has an outside diameter 18 in. and inside diameter 12 in., as shown in the figure. The shaft is rated for a maximum shear stress of 4500 psi. (a) If the shaft is turning at 100 rpm, what is the maximum horsepower that can be transmitted without exceeding the allowable stress? (b) If the rotational speed of the shaft is doubled but the power requirements remain unchanged, what happens to the shear stress in the shaft? 18 in. 100 rpm 12 in. 18 in.

A stepped shaft ABCD consisting of solid circular segments is subjected to three torques, as shown in the figure. The torques have magnitudes of 12.1 kip-in., 9.1 kip-in., and 8.5 kip-in. The length of each segment is 25 in. and the diameters of the segments are 3.5 in., 2.75 in., and 2.5 in. The material is steel with shear modulus of elasticity G = 11.6 x 10° ksi. (Assume that the +x-axis is to the right.) 12.1 kip-in. 9.1 kip-in. 8.5 kip-in. |3.5 in. h 12.75 in. | 2.5 in. в 1 -25 in. 25 in. -25 in. (a) Calculate the maximum shear stress Tmax in the shaft. (Enter the magnitude in ksi.) ksi Calculate the angle of twist o, (in degrees) at end D. (Use the statics sign convention.) (b) If each segment must have the same shear stress, find the required diameter (in inches) of each segment in part (a) so that all three segments have shear stress Tmax from part (a). CAB = in. dBc = in. dcD in. What is the resulting angle of twist at D (in degrees)? (Use the statics sign convention. Due to…

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A tube with the cross section shown in the figure is subjected to a constant torque of T. For a given maximum shear stress of Tava, determine the factor by which the torque carrying capacity of is increased if the half-circular section is reversed from the dashed-line position to the section shown. The tube is 0.1 in thick.