ELASTIC CHARACTERIZATION OF ISOTROPIC MATERIALS BY A SINGLE TEST BASED ON THE EXPERIMENTAL-DETERMINATION OF NATURAL FREQUENCIES USING LASERINTERFEROMETRY

An experimental method is proposed for the elastic characterization of an isotropic material based upon the vibration natural frequencies re corded by means of a single assembly and experiment. Speckle heterodyn e optic interferometry is applied to detect the tangential component o f the vibration at a point. The sample is a slender rod excited throug h a broad-spectrum percussion, where the vibration recorded is a super position of the transverse and torsional natural modes. Spectral analy sis of the vibration allows the identification of the transverse and t orsional natural frequencies, This is followed by calculation of the e lastic moduli. (C) 1997 Acoustical Society of America.