Snecma

Safran Aircraft Engines

Julien Griffaton

Valerio Gerez

Serge Blanchard

Gregory Guillemand

Grégory Guillemand

A method including acquiring a current vibration signal of an engine component mechanical vibration across a set of a measuring period P of changes in shaft speed N; capturing the signal during the period P; synchronizing the signal relative to the changes in the speed N; transforming the signal into a frequency signal for obtaining frequency spectrum lines arranged according to the speed N; calculating the mean amplitude of the spectrum lines to obtain a current vibration signature for the engine; calculating a deviation ratio between the signature and a healthy reference vibration signature; and comparing the deviation ratio to the defect indicators in a predefined database, listing the theoretical damage to the roller engine bearings so as to determine potential damage to the roller bearing.

Method for detecting damage in at least one engine roller bearing

A method and a system for monitoring a turbojet engine. The method acquires a signal representative of a vibratory level of an operating rotor of the turbojet engine, acquires a rotation speed of the rotor during operation, compares the amplitude of the signal with at least one predetermined threshold based on the rotor rotation speed and, in event an amplitude peak exceeds the threshold, analyzes the signal over a time slot defined around the amplitude peak to determine if the phenomenon at the origin of the amplitude peak is a mechanical shock undergone by the rotor of the turbojet engine or an electronic interference of the signal.

Method and system for monitoring a turbojet engine

The invention relates to a method of detecting damage in a bearing supporting at least one rotary shaft of an engine in rotation, the method consisting in: defining a measurement period corresponding to a range of speeds of rotation of the shaft during renewable activity at low speeds of operation of the engine; acquiring over the entire measurement period a vibratory signal representative of acceleration of components of the engine; sampling the vibratory signal as a function of the speed of rotation of the shaft during the measurement period; transforming the sampled vibratory signal into a frequency signal to obtain frequency spectrum lines as a function of the speed of rotation of the shaft; calculating the mean of the amplitudes of the spectrum lines; determining amplitude peaks around multiples of the theoretical frequency of a damaged roller; calculating the ratio between each amplitude peak and the amplitude level determined for a sound bearing; and comparing the ratio that is obtained with at least one predetermined damage threshold.

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Paris, France

Julien Griffaton