# Critical Speed of a Rotating Shaft - Dunkerley's method

## Description

In solid mechanics, in the field of rotordynamics, the critical speed is the theoretical angular velocity that excites the natural frequency of a rotating object, such as a shaft, propeller, leadscrew, or gear.

Dunkerley’s method is used in mechanical engineering to determine the critical speed of a shaft-rotor system.

Related formulas## Variables

N | critical speed(r.p.m.) (1/s) |

E | young's modulus (pascal) |

I | Second moment of area (m^{4}) |

m | mass of the shaft (kg) |

L | length of the shaft between points (m) |