Research On Acoustic Characteristics Of Periodic Perforated Damping Composite Plate Structure

Damping materials is laid on the plate and shell structure, can effectively restrain the vibration and noise radiation of the structure effectively.Base on the principle of damping reduction and frequency properties of viscoelastic,with the method of finite element and boundary(FEM+BEM), the periodic opening damping composite panels model is established, the acoustic characteristics of composite structure is studied in this paper. For the study of damping materials’ geometrical and material parameters to curb the car noises and body weight, the paper will identify the optimal parameters of damping material controlling the radiation of composite structure noise and enhancing the performence of sandwich plate’s sound insulation,and optimum damping materials’ geometry and material parameters.This paper main research content includes:1 The periodic opening damping composite structure finite element model is proposed. Using the modal strain energy method, calculated the composite structure of the modal loss factor, damping composite structure for periodic hole acoustic performance study laid a foundation.2 Based on the principle of damping vibration, and reference the periodic boundary conditions, according to the structural sound radiation theory, studied the periodic hole acoustic radiation characteristics of damping plate structure, through comparing the application of damping plate structure acoustic radiation characteristics, found its advantages. Find the noise radiation of the optimal opening rate, opening shape and noise radiation with the law of the variation in thickness of damping layer.3 To study the periodic opening damped sandwich plate structure acoustic radiation characteristics and sound insulation, found the periodically opening damped sandwich plate structure to optimize the size of the damping materials through comparison; analyzes the opening rate damping materials, thickness of damping layer, the structure of the cycle number effect on the sound radiation characteristics of sandwich plate structure; Studied the geometric parameters of damping materials, the material parameters effect on the sound insulation properties of the sandwich panel structure.4 Using BK equipment to measure the acoustic characteristics of periodic opening damping composite structure, and according to its result compared with the simulation, proved the the accuracy of the simulation.