Research Of Acoustic Characteristics For Closed Cavity Base On The Particle Damping Composite Structural Panels

NOPD (Non Obstructive Particle Damping) is a new kind of damping technology, has agood vibration reduction effect, convenient use, low price, etc. In recent years, scholarsrespectively to study the particle-damping material particle size, particle properties, filling rateon the structure vibration damping effect at home and abroad. But the particle damping materialsused in the noise control research is less. Therefore, this paper aims to explore the particledamping materials with the aid of a closed cavity structure on the influence of the acousticcharacteristics of the closed cavity.This paper mainly study from the following aspects:(1) According to the steady-state flow method, experimental method is utilized to extractthe damping characteristics of particle damping materials--the loss factor curve.(2) According to the theory of modal analysis, as an incentive to force hammer inputdevices, using SISO frequency domain method for closed cavity structure modal experiment. Atthe same time, according to the theory of finite element closed cavity structure finite elementmodel is established, by using Nastran computing simulation mode. Compare test results andsimulation results to verify the accuracy of the simulation model.(3) Using the theory of acoustic finite element, closed cavity acoustic finite element modelis established, and calculating the acoustic modes. According to the sound-solid coupled theoryof modal analysis, calculate and analysis when no particle damping materials and particledamping material closed cavity acoustic-solid coupled modal characteristics.(4) By means of acoustic pressure sensor, a vibrator, signal acquisition analyzer, such as testand analysis of different number of particle damping materials on the effects of cavity pressure.At the same time, with the help of simulation method respectively different simulation model isbuilded, and use the simulation method to validate it.Research shows that particle damping materials for closed cavity structure of sound-solidcoupling mode has certain influence, and with the increase of particle damping materials,coupling modal frequency increases. The particle damping material to reduce noise has a certaineffect in a closed cavity.