Question

Problem 1 (50 points) A countershaft carrying two V-belt pulleys is shown in the figure. Pulley A receives power from a motor through a belt with 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. 230 mm F: 30-mm dia. 280 mm 300 mm 250-mm dia. 400-mm dia 1000 N 150 N (a) Compute the torque acting on the shaft between pulley A and pulley B. Assume that both bearings are frictionless. Draw a schematic of the shaft showing how torque is applied to the shaft at pulley A and at pulley B. (5 points) (b) Determine the belt tension forces (Fi and F:) acting on pulley B. Assume the shaft is running (c) Assess the shaft design for failure under static loading conditions. Compute the stresses act constant speed. (5 points) the shaft at Pulley B. Determine the design factor (n) for a shaft comprised of steel with Sut Suc 250 MPa and Syt- Syc- 200 MPa. The max strain at failure for this material is 209 Along with the design factor, specify the name of the chosen failure theory (3 0 points) (d) The next step is to analyze failure under dynamic or variable loading (i.e. fatigue analysis). Identify which stress components calculated in part (c) that are alternating and which are st Iternating). Using the von Mises stress measure, calculate both the alternating (aa) mid-range (om) stresses in the shaft at Pulley B. (10 points)

Answer 1