고체역학 (Gere) — Torsion: Problem 3.3-13

3.3-13 Three identical circular disks $A, B$, and $C$ are welded to the ends of three identical solid circular bars (see figure). The bars lie in a common plane and the disks lie in planes perpendicular to the axes of the bars. The bars are welded at their intersection $D$ to form a rigid connection. Each bar has diameter $d_1 = 10 \text{ mm}$ and each disk has diameter $d_2 = 75 \text{ mm}$. Forces $P_1, P_2$, and $P_3$ act on disks $A, B$, and $C$, respectively, thus subjecting the bars to torsion. If $P_1 = 100 \text{ N}$, what is the maximum shear stress $\tau_{\text{max}}$ in any of the three bars?