고체역학 (Gere) — Axially Loaded Members: Problem 2.4-20

2.4-20 A rigid bar $ABCD$ is pinned at point $B$ and supported by springs at $A$ and $D$ (see figure). The springs at $A$ and $D$ have stiffnesses $k_1 = 10\text{ kN/m}$ and $k_2 = 25\text{ kN/m}$, respectively, and the dimensions $a$, $b$, and $c$ are $250\text{ mm}$, $500\text{ mm}$, and $200\text{ mm}$, respectively. A load $P$ acts at point $C$. If the angle of rotation of the bar due to the action of the load $P$ is limited to $3^\circ$, what is the maximum permissible load $P_{max}$?