HW Problem 5: A 150 kW motor drives a hollow round shaft at1,200 rpm. The outer diameter of the shaft is 100-mm and the innerdiameter is 0.95*outer diameter. It is made of AISI 1050 WQ&Tat 425- deg C.
(a) Look online or the book and explain briefly what “WQ&T”in the material designation stand for, and how it is different thanOQ&T. Which is stronger at the specified temperature?
(b) Determine the maximum torsional shear stress (Tau max) inthe hollow shaft. Write the units. Hint: Use the kW power equation,find torque, and find J to find Tau max. Use N, mm, MPa.
(c) Determine the safety or no safety factor for static loading(ns) according to (i) Tresca theory, and (ii) von-Mises theory.Hint: Read Sy from table and then calculate Ssy by Tresca andvon-Mises. Then use (ns,Tresca) = (Ssy,Tresca) / (Tau max);(ns,von) = (Ssy,von) / (Taumax).
(d) If the calculated safety factor is more than 4.0, whatparameters would you change to bring it down below 4.0 (and ofcourse, above 1.0)?
