고체역학 (Gere) — Stresses in Beams (Advanced Topics): Problem 6.3-8

6.3-8 Consider the preceding problem if the beam has width $b = 75\text{ mm}$, the aluminum strips have thickness $t = 3\text{ mm}$, the plastic segments have heights $d = 40\text{ mm}$ and $3d = 120\text{ mm}$, and the total height of the beam is $h = 212\text{ mm}$. Also, the moduli of elasticity are $E_{Al} = 75\text{ GPa}$ and $E_p = 3\text{ GPa}$, respectively. Determine the maximum stresses $\sigma_{Al}$ and $\sigma_p$ in the aluminum and plastic, respectively, due to a bending moment of $1.0\text{ kN}\cdot\text{m}$.