Computational multiple scattering analysis of elastic waves in unidirectional composites

A numerical procedure is presented in this paper for the two-dimensional, time-harmonic elastodynamic multiple scattering problems for unidirectional fiber-reinforced composites. The proposed procedure is based on the eigenfunction expansion of the displacement potentials and the numerical collocation method to solve the expansion coefficients, and is capable of modeling arbitrary fiber arrangements. To demonstrate the applicability of the procedure, the P and SV wave propagation characteristics in unidirectional fiber-reinforced composites are analyzed for different fiber arrangements and fiber volume fractions. The simulated results are shown to capture the detailed features of the local wave fields in the composites accompanying the mode conversion. From the computed wave fields, the effective phase velocities of the composites are identified as functions of the frequency, and found to be in good agreement with the predictions of a micromechanical model for random composites. The energy transmission spectra of the P and SV waves are also demonstrated, which exhibit the stop-band formation for the composites with regular fiber arrangements

Multiple scattering of elastic waves in unidirectional composites with coated fibers

Proceedings of the 2015 ICU International Congress on Ultrasonics, Metz, FranceA computational method for analyzing the two-dimensional multiple scattering of elastic waves in unidirectional fiber-reinforced media, consisting of elastic cylindrical fibers arranged in an infinitely extended elastic matrix, is presented. The method is based on the eigenfunction expansion of the displacement potentials and the numerical collocation technique to obtain the expansion coefficients. In the present study, the formulation is extended to incorporate the presence of a coating layer between the fibers and the matrix. As an example, the transmission characteristics of longitudinal as well as transverse waves in a unidirectional composite with square array of fibers are analyzed, and the phase velocities in the composite are evaluated. The effect of the coating layer on the wave transmission and stop-band formation behavior is also demonstrated