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King Fahd U niversity of Petroleum & M inerals College of Engineering Sciences Mechanical Engineering Department First Semester (2007-2008) (071) ME 307: MACHINE DESIGN I HW #4 Chapter 7: Fatigue Failure Resulting from Variable Loading DUE DATE: Sat. 01-12-2007 Problem 1 Corresponding to a reliability of 90 %, find the endurance limit and the number of cycles-tofailure of a 1-in round UNS G-10150 cold-drawn steel bar. The bar is subjected to a purely reversing torque of 250 N.m, and is placed in an environment with T = 500°C. Solution ME 307: Machine Design I 1/5 HW 4: Chapter 7 Problem 2 Determine the fatigue strength of a rotating beam made of AISI 1020, hot-rolled steel corresponding to a life of 2 × 103 cycles of stress reversal. Also, determine the life of the specimen corresponding to a stress amplitude of 42 kpsi. The known properties are: σo = 120 kpsi, m = 0.20 and εf = 0.88. Solution Solution Problem 3 Solve Problem 7-12 of the textbook. Solution Problem 4 Solve Problem 7-17 of the textbook. ME 307: Machine Design I 2/5 HW 4: Chapter 7 ME 307: Machine Design I 3/5 HW 4: Chapter 7 Solution Problem 5 ME 307: Machine Design I Solve Problem 7-23 of the textbook. 4/5 HW 4: Chapter 7 Solution Problem 6 ME 307: Machine Design I Solve Problem 7-26 of the textbook. 5/5 HW 4: Chapter 7