Abstract: A method and a device for detecting a fault in a mechanical system comprising a rotating member and a vibration sensor transmitting a temporal vibration signal. The method comprises processing the temporal vibration signals transmitted over a predetermined period in order to transform the temporal vibration signals firstly into angular vibration signals, then into frequency vibration signals. Next, series of amplitudes are generated, each series being associated with a specific frequency channel and comprising the amplitudes of the frequency vibration signals for this frequency channel. The frequency channels displaying an increasing trend consistent with the fault of interest are then identified. The frequency channels that display an increasing trend are then compared with characteristic frequencies of a known fault of interest in order to check for the possible presence of such a fault in the mechanical system.

Abstract: A method for monitoring the engine speed of a rotating machine, includes constructing a raw spectrogram from a vibratory signal; denoising the spectrogram to obtain an equalised spectrogram, the denoising including a first sub-procedure of determining a foot of the spectrogram, the foot of the spectrum being a set of random harmonic components contained in the raw spectrogram, the first sub-procedure including a first sub-sub-procedure of constructing a regression function robust to the peaks of the spectrogram, the regression function being applied to a logarithm of the spectrogram or to the spectrogram; a second sub-sub-procedure of determining the foot of the spectrum from the regression function; a second sub-procedure of determining the equalised spectrogram from the foot of the spectrogram; separating sources in the equalised spectrogram by determining an estimator of the frequencies of interest; determining an instantaneous speed of rotation of the engine speed from the estimator.

Abstract: A method and a device for detecting a fault in a mechanical system comprising a rotating member and a vibration sensor transmitting a temporal vibration signal. The method comprises processing the temporal vibration signals transmitted over a predetermined period in order to transform the temporal vibration signals firstly into angular vibration signals, then into frequency vibration signals. Next, series of amplitudes are generated, each series being associated with a specific frequency channel and comprising the amplitudes of the frequency vibration signals for this frequency channel. The frequency channels displaying an increasing trend consistent with the fault of interest are then identified. The frequency channels that display an increasing trend are then compared with characteristic frequencies of a known fault of interest in order to check for the possible presence of such a fault in the mechanical system.

Abstract: A method for determining the cyclostationarity of a vibration signal transmitted by a vibration sensor arranged on a mechanical system and allowing a cyclostationarity indicator I? to be calculated. The present disclosure also relates to a method for arranging vibration sensors, using the method for determining cyclostationarity applied to the signals transmitted by these vibration sensors at different positions and orientations. A position of a vibration sensor is validated as a function of this cyclostationarity indicator I?. The present disclosure finally relates to a method for monitoring a mechanical system 10 using the method for determining cyclostationarity to determine the cyclostationarity of the vibration signals relating to the mechanical system before calculating the monitoring indicators of the mechanical system.