Short Time Vibration Analysis and Parameterisation as a Tool for Machine Prototypes Testing

The paper outlines the idea of using the short-time vibration signal processing for testing machines of a complex design, particularly the machines consisting of many subassemblies with a non-stationary (e.g. cyclic) operation modes. The method presented consists in graphic representation of vibrations of subassemblies in the form of a trace on a plane. It is created by associating instantaneous rms values of vibration acceleration and instantaneous Rice frequency values obtained as a result of short-time signal processing. On the basis of the shape, orientation of the created trajectory and / or dispersion / concentration of points on the Rf – arms plane, the type of non-stationarity of generated vibrations can be identified. The presented methodology can be used for testing machine prototypes. The results in the proposed form can be helpful to determine the type of vibration reduction systems for individual machine subassemblies. It is also possible to detect subassemblies for which an increase in machine capacity results in an increase in the level of generated vibrations. The location of the averaged values of measures obtained for a new machine on the Rf – arms plane can be a reference point for further monitoring of machine vibration and for detection of damage or malfunction of its subassemblies.