Sleeve (muff) coupling: design idealization for torsion When analyzing a sleeve/muff coupling for power transmission, the sleeve is modeled as which type of torsional member? Choose the best option.

Concept
A sleeve (muff) coupling transmits torque through the sleeve that encloses the shaft ends. In torsion analysis, the sleeve is treated as a hollow shaft resisting shear.

Reasoning
T = (π/16)·τ_allow·(D_o^4 − D_i^4)/D_oThis is the torsion relation for a hollow circular member (sleeve).

Common pitfall
Modeling as a thin/thick pressure cylinder is incorrect; there is no internal pressure action—only torsion.

Final Answer
Hollow shaft