Damping Identification Using the Wavelet-based Demodulation Method

Application to Gearbox Signals

Abstract

The identification of damping in vibrational systems from measured free responses is a well-known problem and remains a challenge to dynamics specialists. Compared to an estimation of the stiffness, the damping coefficient or, alternatively, the  damping ratio is the most difficult quantity to evaluate. In this paper, a novel procedure is developed for the identification of  modal damping ratios in a multi-degree-of-freedom vibrational system . The procedure is based on the demodulation technique with respect to the continuous wavelet transform and the Morlet-wavelet function. Numerical simulations demonstrating the applicability of the method to multi-degree-of-freedom vibrational systems are presented. The proposed procedure is also compared with measured response data  from a gearbox.