Natural Frequency:

This method is utilized to measured natural frequency of shaft/beam carrying single or various loads and also its mass is considered for basic mode only. There is an equation is known as Dunkerley's equation that is follows as:

                 --------- (46)

Here ω_n = Natural circular frequency for shaft/beam for basic mode,

ω_n1 = the natural circular frequency of the shaft/beam letting only the load 1 and mass of shaft/beam neglected,

ω_n2 = the natural circular frequency of the shaft/beam letting only the load 2 and mass of the shaft/beam neglected, and

ω_ns = Natural circular frequency of the shaft/beam letting its mass only.

Substituting the relevant values in Equation (46), the value of natural circular frequency 'ω_n' can be calculated.