Localization and quantification of vibratory sources: Application to the predictive maintenance of rolling bearings

Among the methods which make it possible to establish a diagnosis on the operating condition of a mechanism, the vibratory techniques seem very promising and are booming. The signals collected by accelerometers are the result of a mixture of various sources each of which corresponds to operation of a component. The diagnosis and monitoring of each component require the determination of the contribution of each source in the signal collected. The objective of this work is to use and optimize the techniques applied to the inverse problems with the aim of quantifying the contribution of each source in the obtained mixture, more particularly, the sources which are characteristic of a damaged element. However, the inverse problems are generally unstable. These instabilities are often related to the errors of measurement or the parasites contained in the signals and require methods of stabilization. This paper proposes a methodology, based on the restitution of the sources. Thus, the methodology ensures the detection and the localization of a defect of a component by the optimization of the position of a limited number of sensors. Two approaches are then proposed: the numerical approach which employs an updated numerical model of the studied structure and the experimental approach based on the correlation between the position of the sensors and the modal parameters of this same structure. The experimental validation of this methodology is carried out on a casing made up of two bearings.