A Method for Calculating Attenuation in Creeping Materials

TL;DR

This paper introduces a new method for accurately extracting phase lag in signals with nonlinear trends, improving the measurement of attenuation in creeping materials for geophysical applications.

Contribution

The study presents a novel approach to determine phase lag in signals with nonlinear trends, enhancing robustness and reliability in attenuation measurements.

Findings

The method accurately extracts phase lag with low error in artificial signals.

Application to experimental data shows consistent results with previous studies.

Robustness demonstrated across signals with varying nonlinear trends.

Abstract

The phase lag between an applied forcing and a response to that forcing is a fundamen tal parameter in geophysical signal processing. For solid deforming materials, the phase lag between an oscillatory applied stress and the resulting strain response encapsulates information about the dynamical behavior of materials and attenuation. The phase lag is not directly measured and must be extracted through multiple steps by carefully comparing two time-series signals. The extracted value of the phase lag is highly sensitive to the analysis method, and often there are no comparable values to increase confidence in the calculated results. In this study, we propose a method for extracting the phase lag between two signals when either one or both include an underlying nonlinear trend, which is very common when measuring attenuation in creeping materials. We demonstrate the robustness of the method by analyzing artificial signals with known phases and quantifying their absolute and relative errors. We apply the method to two experimental datasets and compare our results with those of previous studies