Acoustic polarization method for determining elastic symmetry and constants of anisotropy in solid media

摘要

Physical principles and instruments for the acoustic polarization method for determining parameters of elastic anisotropy in solid media samples are described. In the part concerning physical principles, the propagation of shear (transverse) waves through anisotropic media is analysed. Transducers that can transmit purely shear linear-polarized waves, an acoustopolariscope, an ultrasonic device and a special coupling medium are needed for measurements. Measurements are made by rotating the samplefirst with the polarization vectors of the source and receiver aligned parallel, and rotating again with the polarization vectors orthogonal. In the first stage of measurements one can determine the spatial orientation of the anisotropic symmetry axes and examine the presence of linear anisotropic absorption and some other effects. The second stage deals with measurements of velocities of longitudinal (compression) and shear waves in the direction of the symmetry axes and in other directions. In the laststage the order of calculation of the whole set of constants of elasticity and the determination of the type of cubic. hexagonal, tetragonal. and orthorhombic elastic symmetry in the rock samples are given. To our mind this method may be useful fordetermining properties and testing samples of concrete. plastics. woods, ceramics, composite and other materials.