Study On The Relationship Between Sound Insulation Characteristics Of Composite Panel And It’s Area

With the comprehensive development of modern society,there have been four major pollutions:noise pollution,air pollution,water pollution and solid waste pollution.Different from other pollutions,noise pollution is highly random and difficult to prevent.Noise is almost accompanied by the development of the machinery industry.After large-scale industrialization,various mechanical equipment and vehicles are used in production,and the noise problem is becoming more and more serious.In order to reduce the noise level and protect acoustic environment,sound insulation technology are widely used as a common noise reduction method at this time.This thesis takes sound insulation specimens with different areas as the research object,and uses simulation software to establish an Acoustic-Structure coupling simulation model.For the thickness of 100mm,the areas are 1.094 m~2,1.64 m~2,2.46 m~2,3.28 m~2,4.38 m~2,5.47 m~2,6.56 m~2,7.66 m~2,and 8.75 m~2 composite hollow sound insulation test pieces to calculate the sound insulation capacity.The specimens have a"steel plate-air layer-rock wool-air layer-steel plate"structure.The simulation result is the sound insulation of each specimen.Firstly,the thesis introduces the acoustics fundamental theory.Starting from the three major equations:continuity equation,state equation,motion equation,the acoustic sound pressure wave equation is derived.Then the energy parameters in the sound field is introduced.The formula for calculating the sound intensity of the reverberant sound field is obtained.Finally,the evaluation index of the sound insulation performance of the test piece is listed.In this paper,the sound transmission loss is selected as the sound insulation performance of the specimen.Combined with the sound pressure wave equation in the theoretical part,the classical wave transfer method is used to analyze the sound insulation performance of single-layer plate,double-layer plate and three-layer plate structures.From the comparison results,the sound insulation performance of three-layer panel is excellent,and the sound insulation performance of single-layer panel is poor.The material used in the composite structure and the plate spacing have an impact on the sound insulation performance.Due to many structural parameters,the three-layer structure provides more choices for the design of sound insulation components.In order to combine the actual problem,the acoustic-structure coupling interface in the multi-physical field simulation software is used to model the acoustic insulation specimens of different areas.Under the condition of retaining the integrity of the structure and the complete diffusion of the sound field in the sound source chamber,the experimental process of sound insulation measurement is simulated.The sound insulation 1/3 octave curve of the specimen in the frequency range of 20 Hz～3150 Hz is obtained.The simulation results show that with the increase of the specimen area,the sound insulation becomes smaller,but the fluctuation of the frequency characteristic curve of the sound insulation becomes smaller and the sound insulation performance becomes stable.When performing simulation calculations on structural units with the same length-width ratio and different areas,it is found that the sound insulation curve of the same structure is not similar,and the sound insulation frequency characteristic curve does not have a unified changing law.In the structure unit of equal area,the length-width ratio of the specimen has little influence on the variation trend of the frequency characteristic curve of sound insulation at low frequency,and the variation trend of the sound insulation curve of all specimens is almost the same.The specimen with small length-width ratio has large sound insulation at low frequency.When the length-width ratio of the specimen is similar,the variation situation of the frequency characteristic curve of sound insulation of the specimen is similar.