Researches On The Acoustic Properties Of Two-dimensional Periodical Hole Rigid Thin Plates

The thin plate structure is a very commonly used mechanical structure in the engineering. The development of science and technology and social humanity puts forward new requirements of vibration damping and noise reduction. In order to enhance the acoustic characteristics of the thin plate structure, periodic structures become an emerging technology which is widely used in the thin plate structure. This paper presents a method of analyzing the acoustic properties of two-dimensional periodically perforated rigid thin plates and discusses the effects of involved parameters to acoustic property.The balance equation for the medium within one hole is established firstly according to the acoustic balance condition and boundary conditions under the plane wave incidence. Through meshing of the surface and numerical integration method based on the theory of Rayleigh integral, the problem about the distribution of the medium velocity amplitude within one hole is transformed to the problem about the solution of linear equations. Solving the linear equations, the approximate distribution of particle velocity amplitude within one hole is obtained. On this basis, the coefficient matrix is adjusted to get new linear equations by introducing the two-dimensional periodicity. Solving the new linear equations, the distribution of particle velocity amplitude which can meet the conditions of every hole is obtained. To make the results more practicable and understandable, the radiation matrix is deduced to figure out the transmission sound pressure.As examples, the distribution of particle velocity amplitude and transmission sound pressure are computed. According to the principle of controlling variable method, the effects of different sizes and shapes, as well as different incident angles are discussed respectively, then the rule how those parameters affect the acoustic property is concluded.