재질이 주기적으로 불균일한 보에서 굽힘 탄성파의 전파속도

Speed of Bending Wales Propagating in a Bar with Periodically Nonuniform Material Properties

A bar with periodically nonuniform material properties is selected as a one-dimensional model of a flat-panel speaker. This paper describes a theoretical approach to the bending waves propagating in the nonuniform bar. The phase speed of the wave is obtained using perturbation techniques for small amplitude, sinusoidal modulation of the flexural rigidity and mass density. It is shown that the wave speed is decreased due to the nonuniformity of the material properties by the amount proportional to the square of the modulation amplitude.