ABSTRACT
Shafts are used in a variety of ways in all types of mechanical equipment. A shaft, usually a slender member of round cross section, rotates and transmits power or motion. To minimize deflections, shaft materials are generally cold drawn or machined from hot-rolled, plain carbon steel. In the design of circular slender shafts that transmit power at a specified speed, the material and the dimensions of the cross section are selected to not exceed the allowable shearing stress or a limiting angle of twist when rotating. The shaft design process is far simpler when only static loads are present than when the loading fluctuates. Effect of shock load on shaft has been neglected in the preceding derivation. For some equipment, where operation is jerky, this condition requires special consideration. Shaft deflections frequently can be a critical factor, since excessive displacements cause rapid wear of shaft bearings, misalignments of gears driven from the shaft, and shaft vibrations.
