The shafts are usually cylindrical in section, solid or hollow. They are made of mild steel, alloy steel and copper alloys. Shaft may be subjected to the following loads:
Torsional load
Bending load
Axial load
Combination of above three loads.
The shaft are designed on the basis of strength and rigidity.
Shafts are also used to transmit power from a motor to a pump or compressor, from an engine or turbine to a generator, and from an engine to axle in automobiles. During power transmission, the shaft is subjected to torque which causes twist of the shaft.
A shaft needs to be designed that the excessive twist is avoided and the induced shear stress is within prescribed limits.
