# Compound shaft-axial force,internal force

1. Nov 9, 2005

### chandran

There is a compound solid shaft. Outer shaft is made of material A and inner shaft is made of material B. One end of the shaft is fixed and another end has a force of F.

Will the internal force in each of the shaft members vary? why. If i pull with a force F, I think the internal force F will be same each of the solid members.

Similarly if a torque is applied at one end and the other end is fixed, will the internal torque differ in the two shafts

2. Nov 10, 2005

### Staff: Mentor

The stiffer material will bear greater load.

In a compound shaft, the displacements of the different materials are equal.

In the case of a torque, the shear stresses will also be different. For one, the torsional stress at radius r is given by,

$$\tau\,=\,\frac{Tr}{J}$$

where T is applied Torque, r is radius and J is torsional moment of inertia.