_______________________________________________________________________ PROBLEM (9.8) A shaft with an a x b rectangular cross section is acted upon by an axial tensile load P and a torque T (Fig. P9.7). Determine the largest permissible value of P if the allowable tensile stress in the member is limited to σ all . Given: a = 100 mm, b = 50 mm, T = 5 kN ⋅ m, σ all = 120 MPa SOLUTION By Table 5.1, with a b = 2 : 5(103 ) T = = 81.3 MPa α ab 2 (0.246)(0.1)(0.05) 2 P σ= = 200 P MPa ( P in MN ) (0.1)(0.05) Hence τ= σ1 = σ σ + ( ) 2 + τ 2 = σ all 2 2 = 100 P + (100 P) 2 + (81.3) 2 = 120 (120 − 100 P) 2 = 10, 000 P 2 + 6, 609.7 14, 400 − 24, 000 P + 10, 000 P 2 = 10, 000 P 2 + 6, 609.7 or Pall = 0.3246 MN = 325 kN Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful.