MecMovies 4.0 : M6.21: Maximum Torque for Composite Shaft

Diagram shows an aluminum shaft A B with a support at A, marked 1 of length 4,000 millimeters and a brass shaft B C with a support at C, marked 2 of length 3,000 millimeters with a flange in between at B. The shafts are centered on the x axis. A torque T is applied at B.

The procedure to solve this problem
can be outlined as:

• Stress relationship
Expressions for shaft torques can be obtained from the elastic torsion formula. Substituting these expressions into the compatibility equation, we will derive a relationship between the shear stresses in the two shafts.

• Controlling shear stress
Using the relationship between shear stresses in the two shafts and the allowable stresses, the shaft that controls the design can be determined.

• Shaft torques
Once the shaft stresses are known, the internal torques $T_{1}$ and $T_{2}$ and the maximum external torque $T$ can be computed.