Energy-based indexes for analysis of vibrations from rotating machinery based on the Hilbert-Huang transform

The aim of the paper is to introduce a parameter indicating a possible progressive deterioration of rotating machinery affected by any dynamic misalignment (due to increasing eccentricities, uneven mass distribution, propagating cracks, etc.). Such parameter, which has to be considered as a damage index, is based on a series of post-processing algorithms to be implemented on the vibration signals acquired on static supporting elements. The vibrations acquired from rotating machinery could be influenced by non-stationary and non-linear features, especially when the rotating elements are affected by dynamical unbalances due to misalignments or uneven mass distribution. The authors use the Hibert-Huang Transform tool, that is able to decompose the original signal into Intrinsic Mode Functions (IMFs), each of them holding quite significant information about the instantaneous frequencies and the energy content of the original signal.