고체역학 (Gere) — Stresses in Beams (Advanced Topics): Problem 6.5-7

6.5-7 The cross section of a steel beam is constructed of a HE 450A wide-flange section with a $25\text{ cm} \times 1.5\text{ cm}$ cover plate welded to the top flange and a UPN 320 channel section welded to the bottom flange. This beam is subjected to a bending moment $M$ having its vector at an angle $\theta$ to the $z$ axis (see figure). Determine the orientation of the neutral axis and calculate the maximum tensile stress $\sigma_t$ and maximum compressive stress $\sigma_c$ in the beam. Assume that $\theta = 30^\circ$ and $M = 18.5\text{ kN}\cdot\text{m}$. Note: The cross-sectional properties of this beam were computed in Examples D-2 and D-5.