Study On Damping And Sound Absorption Materials Of Composite Structure Plate The Sound Insulation Performance

With the rapid development of society,the noise from the traffic,factories and industry is growing and affects people's normal work,study and rest,even endangers the health.Thus,reducing the noise is the inevitable trend of the pursuit that people enjoy a comfortable life.The most effective way to reduce noise is to cut off the way of sound transmission.The method to improve sound insulation performance of the monolayer homogeneous materials is only to increase its weight or surface density.The method results in weight increase and energy waste.Compared with the monolayer homogeneous materials,composite panel has the characteristic of high strength,light weight,functional diversification and so on.Thus,it's necessary to study the sound insulation performance of the composite panels.So far,there are few researches about composite structure of damping materials and sound absorption materials.Therefore,this is the focus of this study.The paper first study the sound insulation performance of the single-layer panel and grasp its change law.Then,the focus of the research is the effect and mechanics of damping materials and sound absorption materials on sound insulation performance.First,the paper studies the sound insulation performance of the monolayer homogeneous materials,including 45#steel panels,1060 Aluminum panels,constrained damping panels,polyurethane damping sheets and GFRP.It is found that the sound insulation performance curve accords with the sound insulation characteristic curve of single-layer homogeneous material.The curve is divided into three zones,which contains the stiffness damping control area in 100?500 Hz,the quality control area in 500?2000 Hz that its value of sound insulation increases 4.7-5.0 dB by calculation doubling frequency and it's consistent with the theoretical values,the coincidence effect area in 2000?5000 Hz.With the increase of thickness or the number of layers of five kinds of material,it improves the sound insulation performance in frequency range from 100 to 5000 Hz.In the 100?125 Hz stiffness influence zone,Increasing the thickness improves the stiffness of the material,reduces the slope of sound insulation,weakens the first resonance,and improves sound insulation performance.With the increase of thickness,it make sound insulation performance increase and weakens the resonance between 125?500 Hz.As for complex mass law in 500?2000 Hz,the calculated values agree with the measured values.With the increase of thickness or the number of layers,coincidence effect moves towards low frequency during 2000?5000Hz.Secondly,The effect of damping layer on sound insulation performance is studied by damping composite material with 1060 Aluminum panels and 6 layers of GFRP.The research finds that the use of damping coating not only weakens the resonance of damping control region,but also makes the coincidence effect move to high frequency.With the increase of damping coating thickness,the improvement of sound insulation performance is greater and the degree of improvement is greater than the influence of quality factors.The greater loss factor of the damping coating gets,the better sound insulation performance of the double-layer panel becomes,the weaker resonance of the resonance region gets,and the larger range that the coincidence effect moves to the high frequency becomes.Finally,the influence of the thickness,the type of sound absorption material and the ratio of sound absorption material and air layer on sound insulation performance is studied.It is found that the increase of the thickness of melamine foam in sandwich layer has three following results:The resonant trough moves towards low frequency and the sound insulation performance decreases at low frequency 100?315 Hz;The sound insulation performance is improved and the effect is much greater than the quality factor in the medium frequency 200?1000 Hz;At high frequency 2000?5000 Hz,the coincidence effect moves to high frequency and the sound insulation performance increases.Changing the sandwich sound-absorbing material has greater effects on the sound insulation performance during 200?1000 Hz.The reason is that the sound absorption coefficient of five kinds of materials has larger variation during the area.What's more,the better sound absorption performance gets,the better sound insulation performance becomes.By changing the ratio of the melamine foam to the air layer,the increase of the air layer proportion can save a large amount of sound-absorbing materials with the same sound insulation performance requirements.