고체역학 (Beer) — Torsion: Problem 3.27

3.27 For the gear train shown, the diameters of the three solid shafts are: \[d_{AB} = 20\text{ mm} \quad d_{CD} = 25\text{ mm} \quad d_{EF} = 40\text{ mm}\] Knowing that for each shaft the allowable shearing stress is \(60\text{ MPa}\), determine the largest torque \(T\) that can be applied.