Automatic Interpretation of Small Strain Shear Modulus Measurement Using Bender Elements

Abstract

This paper reports on a novel procedure for the automatic calculation of small strain shear moduli in bender element experiments. The interpretation of the output signal in such experiments is notoriously difficult because the input wave gets distorted as it travels through the sample, hindering the visual comparison between the input and output signals. Conversely, the procedure described here maximises the correlation between the experimental output signal and its computational simulation and returns the shear modulus for which the maximum is attained. The maximisation procedure is encoded as a fixed point algorithm to remove its sensitivity to the initial choice of the shear modulus, and extend the convergence basin of the absolute maximum correlation over many local extrema.