1.Loading date：April., 15^th,2023
2.Country：Morocco
3.Commodity：Closed cell aluminum foam panel   
4.Size:  1000mm x 90mm x 20mm/2000mmx115mmx20mm/2000mmx80mmx42mm
5.Quantity：50PCS
6.Usage：Shock absorber testing

7.Contact information: 
Sales Manager： Jessica

Email: sales22@chinabeihai.net

The closed cell aluminum foam plate is made into high efficiency sound absorbing plate after perforation treatment (φ2mm hole, perforation rate 1~3%), which has excellent sound absorption performance, and the sound absorption rate can reach 60%~90%. Because the surface of this material has no plane, it has excellent surface diffuse reflection sound absorption function, and at the same time has perforated Helmholtz resonance absorber sound absorption function to ensure a high sound absorption rate. In addition, in a humid environment, ordinary sound-absorbing materials absorb moisture and expand, and the sound absorption coefficient is greatly reduced, while the aluminum foam material does not absorb moisture, and its sound absorption rate is not reduced.
As the thickness of air layer increases from 0mm to 90mm, the main frequency of sound absorption decreases from 2000Hz to about 300Hz. When the thickness of air layer is 10, 30, 60, 90mm, the main frequency of sound absorption rate is about 1000Hz, 500Hz, 400Hz, 300Hz respectively. According to the noise frequency distribution design foam rate sound absorption plate behind the air layer thickness. The main frequency of noise generated by cars in highway, river bottom tunnel and submarine tunnel is around 400Hz, which is low frequency noise, so the air layer of 60mm thick is set behind the foam aluminum acoustic plate of highway sound barrier, river bottom and submarine tunnel acoustic wall, which has good noise reduction effect. The noise of railroad is medium-high frequency noise above 1000Hz, and 20mm thick air layer is set behind the foam aluminum sound-absorbing panel, which has good noise reduction effect.