For two shafts connected in a parallel, which of the following statement is true?
- ATorque in each shaft is the same
- BShear stress in each shaft is the same
- CAngle of twist of each shaft is the sameCorrect
- DTorsional stiffness of each shaft is the same
Solution
Concept
Compatibility in parallel shafts
Formula
θ₁ = θ₂; T = T₁ + T₂
Step-by-step solution
1. In a parallel connection both shafts are fixed at the same two ends. 2. So both must twist by the same angle. 3. The total torque is shared: T = T₁ + T₂.
Explanation
When shafts are connected in parallel, the angle of twist is common to both, and the torque is divided in proportion to their torsional stiffness (GJ/L). The torque and the shear stress in the two shafts are generally different.
Shortcut
Series: same torque. Parallel: same twist.
Common mistake
Choosing the same torque (series result).
Correct answer: C) Angle of twist of each shaft is the same