고체역학 (Beer) — Analysis and Design of Beams for Bending: Problem 5.140

5.140 Assuming that the length and width of the cover plates used with the beam of Sample Prob. 5.12 are, respectively, \(l = 4\text{ m}\) and \(b = 285\text{ mm}\), and recalling that the thickness of each plate is \(16\text{ mm}\), determine the maximum normal stress on a transverse section (a) through the center of the beam, (b) just to the left of D.