고체역학 (Beer) — Pure Bending: Problem 4.56

4.55 and 4.56 Five metal strips, each $0.5 \times 1.5\text{-in.}$ cross section, are bonded together to form the composite beam shown. The modulus of elasticity is $30 \times 10^6\text{ psi}$ for the steel, $15 \times 10^6\text{ psi}$ for the brass, and $10 \times 10^6\text{ psi}$ for the aluminum. Knowing that the beam is bent about a horizontal axis by a couple of moment $12\text{ kip}\cdot\text{in.}$, determine (a) the maximum stress in each of the three metals, (b) the radius of curvature of the composite beam. Note: For Problem 4.56 (Fig. P4.56), the stacking sequence from top to bottom is Steel, Aluminum, Brass, Aluminum, and Steel.