Elastic characterization of isotropic materials by a single test based on the experimental determination of natural frequencies using laser interferometry

Abstract

An experimental method is proposed for the elastic characterization of an isotropic material based upon the vibration natural frequencies recorded by means of a single assembly and experiment. Speckle heterodyne optic interferometry is applied to detect the tangential component of the vibration at a point. The sample is a slender rod excited through a broad-spectrum percussion, where the vibration recorded is a superposition of the transverse and torsional natural modes. Spectral analysis of the vibration allows the identification of the transverse and torsional natural frequencies. This is followed by calculation of the elastic moduli.