고체역학 (Beer) — Principal Stresses Under a Given Loading: Problem 8.2

8.1 A W10 × 39 rolled-steel beam supports a load P as shown. Knowing that P = 45 kips, a = 10 in., and σall = 18 ksi, determine (a) the maximum value of the normal stress σm in the beam, (b) the maximum value of the principal stress σmax at the junction of the flange and web, (c) whether the specified shape is acceptable as far as these two stresses are concerned. 8.2 Solve Prob. 8.1, assuming that P = 22.5 kips and a = 20 in.