Useful Equations for Shaft Design

Shaft Power Equation

To calculate the power of a shaft, you need to multiply the torque of the shaft by it’s angular velocity.

Power Equation of a Shaft

Average Shaft Power

The average power is calculated by applying average values for the shaft power equation.

Average Shaft Power

Shaft Bending Stress

The largest alternating and mean bending stresses are at the outside surface.

Shaft bending stress

Shaft Torsional Stress

Shaft torsional stress is derived from the shaft bending stress.

Shaft torsional stress

Torsion Equation of a Shaft

Torsion Equation

Torque and the Diameter Equation for a Solid Shaft

To calculate the diameter of the shaft we can, derive a equation from the torsion equation. And the equation below also can be used for calculating the bearable twisting moment of a give shaft.

Diameter equation for a solid shaft

Torque and the Diameter Equation for a Hollow Shaft

Even we most commonly use solid shafts, in some cases, we have to use hollow shaft. Since the polar moment inertia of a hallow shaft is kind of different,

Diameter equation for a hallow shaft