Sound Insulation Performance Of The Modular Partitions In The Test Opening Of A Sound Insulation Room

The main noise sources of railway vehicles are outside the car bodies,so the car body should have sufficient sound insulation performance to ensure a good sound environment inside the car.The airborne sound insulation of doors,windows and car bodies needs to be measured in the sound insulation room.Generally,the test piece will be smaller than the test hole.It is necessary to add a shim wall with high enough sound insulation performance in the hole,and place the test piece in the shim wall.For test pieces of different sizes,the shim wall should be left with corresponding size test piece mounting holes.The repeated disassembly and assembly of the interstitial wall will consume a lot of manpower and material resources.Therefore,it is necessary to study a modular and detachable interstitial wall to meet the installation needs of different sizes of specimens.In this paper,a modular shim wall is designed,and its sound insulation performance is analyzed through simulation calculation.First of all,according to the sound insulation range of the common car body components of railway vehicles,the lower limit of the sound insulation of the shim wall is determined.Combined with the requirements of disassembly and easy installation,a high sound insulation,modular shim wall is designed,which is detachable.Equipped with steel frame,composite structure sound insulation module and horizontal clamps for fixed sound insulation module;secondly,using numerical simulation software,the sound insulation capacity of sound insulation modules in different areas was calculated,and compared with the sound insulation capacity of aluminum profiles in the same area.Contrast;Finally,the sound insulation module is optimized by changing the damping of the material in the sound insulation module,the sound absorption material and the steel plate spacing,and according to the numerical simulation calculation results.The main conclusions are as follows:The theoretical calculation shows that the sound insulation of the interstitial wall is52.2d B,and the sound insulation of the typical test piece is 32.2d B after consulting the literature.The sound insulation of the interstitial wall is more than 15 d B higher than the sound insulation of the test piece,which meets the requirements of sound insulation testing;through the combination of modules,1m~2～10.7 can be assembled There are 12 kinds of openings in m~2,of which five commonly used areas are 1m~2,1.5m~2,2m~2,3m~2,4m~2,which can be used to test the sound insulation performance of car doors,windows and wall specimens,and the disassembly and assembly can be manually operated.Easy to install.In the five common areas,in the frequency range of 100～3150Hz,the sound insulation of the interstitial wall sound insulation module is more than 15 d B higher than that of the aluminum profile,which proves that the sound insulation of the sound insulation module meets the requirements;as the area increases,it is lower before the resonance frequency In the frequency band and the315～630Hz frequency band,the sound insulation will be reduced,and the other frequency bands will not change much.Increasing steel plate damping,optimizing sound-absorbing materials,and optimizing the steel plate spacing will effectively increase the sound insulation of the sound insulation module.Comprehensive damping,weight factors and improvement of the sound insulation effect,natural rubber can be selected as the damping material,and super Fine glass wool is used as a sound-absorbing material,and the spacing between steel plates is125 mm.