Method and vibration monitoring device in torsion of a rotating shaft of a turbine engine.

Method and vibration monitoring device in torsion of a rotating shaft of a turbine engine. The monitoring method according to the invention comprises: - a step of obtaining (E10) a vibratory acceleration signal from a sensor located on a stationary component of the turbine engine, the vibration signal being characterized by a carrier frequency ; - an evaluation step (E20) of a frequency spectrum of the vibration signal; - a search step (E30) of a pair of spectral lines of amplitudes greater than at least a first threshold spread in the spectrum around the carrier frequency of the vibration signal and spaced therefrom with a twist frequency of the tree ; and - where appropriate, a step of issuing a warning.