ME 4140-W90/6140 Instructor: Ahsan Mian Spring 2013 Homework 7 Due: Tuesday April 9, 2013 Mode of submission: D2L Drop Box or in-person Problems 3-94, 3-100, 3-119 4. The motor shown below runs at 2000 rpm transmitting power to another shaft connected through flat belt. The drive shaft of diameter of mm is push-fitted with the pulley of an internal diameter of mm creating interface friction factor of 0.3. The drive shaft and the pulley are made of AISI 1040 cold-drawn steel and gray cast iron, respectively. a. What are the principal normal stresses in the pulley and the shaft due to press-fitting them together? Compare them with the yield strengths of the respective materials? b. Find the maximum power that the motor will safely transmit. Drive MotorDrive MotorPulleyDrive shaft60 mm200 mm
5. Figure shows the tentative concept of a special load transfer joint in a torque measuring fixture. It is important to accurately maintain distance L at a constant value. The joint is be constructed using a 2 inch long cylinder of ultrahigh strength AISI 4340 steel with a diameter of 1.000 inch, residing in a 0.531 inch radius semicircular groove in a 2 inch wide block of the same material. It has been estimated that a total force of 4000 lb will be distributed across the cylinder as shown. Experimentation has indicated that for satisfactory service, the maximum surface contact pressure should not exceed 250,000 psi. For the proposed design configuration: a. Determine whether the surface contact pressure is below the specified limiting value. b. Plot all the principal normal stress components along z-axis. c. Plot all the principal shear stress components along z-axis. d. Using the results from part c, determine magnitude of the maximum principal shearing stress in the contact region. What is the depth location of the maximum principal shearing stress? 6. Your group manager tells you that she has heard that a cylinder of AISI 1020 HR steel will produce plastic flow in the region…