고체역학 (Gere) — Stresses in Beams (Advanced Topics): Problem 6.2-15

6.2-15 A composite beam is constructed from a wood beam ($75\text{ mm} \times 150\text{ mm}$) and a steel plate ($75\text{ mm}$ width). The wood and the steel are securely fastened to act as a single beam. The beam is subjected to a positive bending moment $M_z = 8.5\text{ kN}\cdot\text{m}$. Calculate the required thickness of the steel plate based on the following limit states: (a) Allowable compressive stress in the wood = $14\text{ MPa}$ (b) Allowable tensile stress in the wood = $14\text{ MPa}$ (c) Allowable tensile stress in the steel plate = $110\text{ MPa}$ Assume that $E_w = 11\text{ GPa}$ and $E_s = 200\text{ GPa}$.