고체역학 (Gere) — Stresses in Beams (Advanced Topics): Problem 6.3-2

6.3-2 A sandwich beam having steel faces enclosing a plastic core is subjected to a bending moment $M = 5\text{ kN}\cdot\text{m}$. The thickness of each steel face is $t = 3\text{ mm}$ with modulus of elasticity $E_s = 200\text{ GPa}$. The height of the plastic core is $h_p = 140\text{ mm}$, and its modulus of elasticity is $E_p = 800\text{ MPa}$. The overall dimensions of the beam are $h = 146\text{ mm}$ and $b = 175\text{ mm}$. Using the transformed-section method, determine the maximum tensile and compressive stresses in the faces and the core.