Robust Skewness-Kurtosis Descriptor for Damping Calibration from Frequency Response

This paper attempts to define simple, consistent, and robust statistical descriptors for the calibration of damping in linear and nonlinear systems through the frequency response in the presence of variability and uncertainties as a result of noise and sampling intervals. The work uses the frequency response of a linear system and a Duffing oscillator simulating hardening and softening springs. The skewness-kurtosis descriptor was observed to be efficiently calibrating the nature of the system and the extent of damping with robustness against the measurement noise and sampling effects. The descriptors allow rapid computation and can be applied to experimental data without the requirement of assuming a specific underlying model. The findings are general and applicable to a very broad spectrum of linear and nonlinear systems and applications.