Multiple scattering of an acoustic wave from a network of cylindrical rods encased in a solid viscoelastic medium

In this paper, the multiple scattering of normally and obliquely incident acoustic waves from a network of cylindrical rods embedded in a viscoelastic medium is investigated. The cylinders can be either isotropic or transversely isotropic. This problem has applications in studying the interaction of ultrasonic waves with composite materials in ultrasonic nondestructive testing. By extending the classical theory of scattering from a single cylinder, the multiple scattering equations are derived incorporating all three kinds of longitudinal, horizontally polarized shear and vertically polarized shear waves in a viscoelastic matrix. The spatial angle of the incident wave is arbitrarily chosen and the backscattered waves can be found in any point of the space. In the proposed method, there are no restrictions on the number of cylinders and/or on the order of scattering. Therefore, the method is capable of handling any order of scattering from any number of cylinders. To experimentally validate the numerical results, a number of experiments are conducted on steel cylinders embedded in a polymeric matrix. The scattered waves from the cylinders are received and their corresponding form functions are obtained. By comparing the numerical and experimental results, a good agreement is observed.