A quantified index for bearing vibration analysis based on the resonance modes of mechanical system

Abstract

In this paper, an envelope estimation algorithm based on the resonance modes of the mechanical system is proposed to apply in the signal processing for the bearing vibrations and the exponential decay frequency of the envelope signal could be further estimated to be a quantified index for the bearing vibration analysis. According to the vibration spectrum of the bearing system, the resonance frequencies in the range of the corresponding resonance modes could be initially designated and further estimated. Under the assumption of stepwise functions for the envelope signals in the corresponding resonance modes, the vibration signal could be decomposed into the sinusoidal function bases with fundamental frequencies at the resonance frequencies. The envelope signals could be derived from their corresponding resonance modes. In addition, the vibration signal could be directly reconstructed from the envelope signals to reject the low-frequency mechanical noise. According to the envelope signals, the exponential decay frequency is also estimated to be a quantified index for diagnosing the running condition of roller bearing. In the simulation study, the envelope spectra show good consistency between the proposed method and the high frequency resonance technique. Finally, the experimental study shows that the envelope estimation algorithm could be effectively applied in the signal processing for the bearing vibrations and the exponential decay frequency could successfully be a quantified index for the bearing defect diagnosis.