Analysis of elastic nonlinearity using the scaling subtraction method

Analyzing the nonlinear part of a signal generated by the response of a sample to an elastic excitation is a powerful tool to gain information on the material microstructure, including the presence of damage. Analysis using band-pass filtering or equivalent methods is often difficult due to the low amplitude of the harmonics contained in the signal. This is the case for the detection of early damage in granular samples with damage induced by a quasistatic loading, as analyzed in this paper. An experimental study, based on the scaling subtraction method, is presented here, showing the possibility of monitoring the variation in the sample nonlinearity during the evolution of damage and allowing linking it to different physical processes. The efficiency of the method in eliminating nonlinear contributions due to the experimental setup is proved through a numerical analysis.