Harmonic plane waves in isotropic micropolar medium based on two-parameter nonlocal theory

In this paper, the system of equations for nonlocal micropolar elastic materials is developed taking into account the assumption that the attenuation functions for the elastic and micropolar material coefficients are different, and applied for harmonic body waves. The dispersion equations of harmonic body waves propagating in a micropolar medium and their cutoff frequencies are obtained in simple form based on the new assumption. The obtained dispersion relations are potentially useful in an inverse problem by fitting the data of elastic and micropolar harmonic waves speed to estimate the elastic and micropolar nonlocal parameters of the medium. Some concerning remarks about the difference between the two-parameter nonlocal theory and the one-parameter nonlocal theory of Eringen are numerically discussed to show the necessary of the developed theory in the problem of wave propagation.