Multi-layer sound attenuating acoustic panel

Abstract

An acoustic panel having rigid, damped faces and an interior layer assembly. The assembly can constructed with minimal layer coupling and common construction adhesives and without the use of mechanical fasteners. The panel is capable of providing significant noise attenuation while maintaining sufficient structural rigidity such that the panel is suitable for a broad range of construction applications.

We claim: 
     
       1. An acoustic panel having a top frame end, a right side and a left side, the acoustic panel comprising:
 a. First and second parallel rigid outer layer structural face panel members, each being spaced apart and having an outer layer density characteristic and an outer layer acoustic reflectivity characteristic and an outer layer sound transmission characteristic; 
 b. A structural frame member disposed between and at said top frame end of said first and second parallel rigid outer layer structural face panel members, 
 c. In a space located between said first and second parallel rigid outer layer structural face panel members, which is not occupied by said structural frame member; a multi-layer outer core comprising:
 i. A plurality of parallel outer core damping layers, each being spaced apart from at least another of said plurality of parallel outer core damping layers and having an outer core density characteristic which is higher than said outer layer density characteristic and an outer core acoustic reflectivity characteristic which is lower different than said outer layer acoustic reflectivity characteristic and an outer core sound transmission characteristic which is lower than said outer layer sound transmission characteristic; 
 ii. In a space between at least two of said plurality of outer core damping layers, a multi-layer rigid inner core comprising:
 a. A formed fiber composite layer with varying geometry and density having a planar first side which is parallel to an outer surface of said plurality of outer core damping layers and having an irregular thickness dimension; where areas of larger thickness have a lower density than areas having a smaller thickness; and 
 b. A substantially planar panel contacting said formed fiber composite layer only at areas thereon with a lower density and a larger thickness. 
 
 
 
     
     
       2. The acoustic panel of  claim 1  wherein said substantially planar panel consists essentially of gypsum. 
     
     
       3. The acoustic panel of  claim 1  wherein said plurality of parallel outer core damping layers comprises two substantially identical adjacent panels. 
     
     
       4. The acoustic panel of  claim 1  wherein said plurality of parallel outer core damping layers comprises layers of beryllium loaded vinyl. 
     
     
       5. A panel of  claim 1  wherein said first and second parallel rigid outer layer structural face panel members comprise oriented strand board. 
     
     
       6. A panel of  claim 1  wherein said first and second parallel rigid outer layer structural face panel members comprise plywood. 
     
     
       7. A panel of  claim 1  wherein said first and second parallel rigid outer layer structural face panel members comprise medium density fiber board. 
     
     
       8. The acoustic panel of  claim 1  wherein said outer layer density characteristic is substantially homogeneous in a first direction and discontinuous in an orthogonal second direction. 
     
     
       9. The acoustic panel of  claim 1  wherein said outer layer density characteristic is discontinuous. 
     
     
       10. The acoustic panel of  claim 9  where said outer layer density characteristic has a central zone with a center zone density characteristic which is discontinuous from a plurality of opposing outer zone density characteristics. 
     
     
       11. An acoustic panel having a top frame end, a right side and a left side, the acoustic panel comprising:
 first and second outer layer structural face panel members, each being spaced apart and having an outer layer density characteristic and an outer layer acoustic reflectivity characteristic and an outer layer sound transmission characteristic; 
 a structural frame member disposed between and at said top frame end of said first and second outer layer structural face panel members, 
 in a space located between said first and second outer layer structural face panel members, which is not occupied by said structural frame member; a multi-layer outer core comprising: 
 a plurality of outer core damping layers, each being spaced apart from at least another of said plurality of outer core damping layers and having an outer core density characteristic which is higher than said outer layer density characteristic and an outer core acoustic reflectivity characteristic which is lower than said outer layer acoustic reflectivity characteristic and an outer core sound transmission characteristic which is lower than said outer layer sound transmission characteristic; 
 in a space between at least two of said plurality of outer core damping layers, a multi-layer rigid inner core comprising: 
 a formed fiber composite layer with varying geometry and density having a planar first side which is parallel to an outer surface of said plurality of outer core damping layers and having an irregular thickness dimension; where areas of larger thickness have a lower density than areas having a smaller thickness; and 
 a substantially planar panel contacting said formed fiber composite layer only at areas thereon with a lower density and a larger thickness. 
 
     
     
       12. An acoustic panel having a top frame end, a right side and a left side, the acoustic panel comprising:
 First and second outer layer structural face panel members, each being spaced apart and having an outer layer density characteristic and an outer layer acoustic reflectivity characteristic and an outer layer sound transmission characteristic;   A structural frame member disposed between and at said top frame end of said first and second outer layer structural face panel members,   In a space located between said first and second outer layer structural face panel members, which is not occupied by said structural frame member; a multi-layer outer core comprising:
 A first layer which is a damping layer, having an outer core density characteristic which is different from said outer layer density characteristic and an outer core acoustic reflectivity characteristic which is different from said outer layer acoustic reflectivity characteristic and an outer core sound transmission characteristic which is different from said outer layer sound transmission characteristic; 
 In a space between said first and second outer layer structural face panel members a multi-layer inner core comprising:
 A second layer which is a layer with varying geometry on a side and varying density; and 
 A panel contacting said second layer only at areas thereon with a larger thickness. 
 
   
     
     
       13. The acoustic panel of claim 12 wherein first and second outer layer structural face panel members are parallel and rigid. 
     
     
       14. The acoustic panel of claim 12 wherein said first layer which is a damping layer, is one of a plurality of outer core damping layers, each being spaced apart from at least another of said plurality of outer core damping layers and having an outer core density characteristic which is higher than said outer layer density characteristic and an outer core acoustic reflectivity characteristic which is lower than said outer layer acoustic reflectivity characteristic an outer core sound transmission characteristic which is lower than said outer layer sound transmission characteristic. 
     
     
       15. The acoustic panel of claim 12 wherein said multi-layer inner core is disposed in in a space between said first and second outer layer structural face panel members and further within a space between said at least two of plurality of outer core damping layers. 
     
     
       16. The acoustic panel of claim 12 wherein said second layer is a formed fiber composite layer. 
     
     
       17. The Acoustic panel of claim 12 wherein said panel is a substantially planar panel. 
     
     
       18. The acoustic panel of claim 14 wherein said multi-layer inner core is disposed in in a space between said first and second outer layer structural face panel members and further within a space between said at least two of plurality of outer core damping layers. 
     
     
       19. The acoustic panel of claim 18 wherein said second layer is a formed fiber composite layer. 
     
     
       20. The Acoustic panel of claim 19 wherein said panel is a substantially planar panel.