고체역학 (Beer) — Pure Bending: Problem 4.89

4.89 For the beam indicated, a couple of moment equal to the full plastic moment $M_p$ is applied and then removed. Using a yield strength of 42 ksi, determine the residual stress at (a) $y = 1$ in., (b) $y = 2$ in. (Beam of Prob. 4.75: Cross section with top and bottom flanges of width 3 in. and thickness 1 in., and a web of width 2 in. and height 2 in. The material is steel with $E = 29 \times 10^6$ psi and $\sigma_Y = 42$ ksi.)