고체역학 (Gere) — Torsion: Problem 3.8-1

3.8-1 A solid circular bar $ABCD$ with fixed supports is acted upon by torques $T_0$ and $2T_0$ at the locations shown in the figure. (a) Obtain a formula for the maximum angle of twist $\phi_{max}$ of the bar. (b) What is $\phi_{max}$ if the applied torque $T_0$ at $B$ is reversed in direction? Dimensions from the figure: Segment $AB$: length $L_{AB} = \frac{3L}{10}$ Segment $BC$: length $L_{BC} = \frac{3L}{10}$ Segment $CD$: length $L_{CD} = \frac{4L}{10}$