LAUSR

The interface/interphase is modeled by distributed springs, and the degree of interface damage is characterized by the flexibility coefficient of the springs. Considering different degrees of damage at different interfaces, a general dispersion equation by the transfer matrix method was obtained. For the purpose of application, the transmission coefficient of finite-period phononic crystals is also derived. Additionally, the band structures and the transmission coefficients are calculated for different degrees of damage to confirm the interface effect on band gaps. A numerical simulation of the transmission coefficient is performed using the commercial FEM software Comsol Multiphysics. The numerical results obtained agree well with the analytical solution. Finally, based on a monotonic decreasing relationship between the degree of interface damage and the central frequency of band gaps and a monotonic relationship between the degree of interface damage and the amplitude of transmission coefficients, a new method how to evaluate the degree of interface damage theoretically is proposed.