Poroelastic acoustical foam having enhanced sound-absorbing performance

Abstract

An optimal shape of a poroelastic acoustical foam which can maximize sound-absorbing effect is disclosed. The poroelastic acoustical foam is made of a wedge-shaped wedge unit where the cross section is reduced in one direction, and a bowl-shaped bowl unit where formed at one end of the wedge unit where the cross section of the wedge unit is small, and the other end, where the cross section of the wedge unit is large, is separated from the wall, forming an air layer.

1 . Poroelastic acoustical foam made of a porous material comprising:
 a wedge-shaped wedge unit where the cross section is reduced in one direction; and   a bowl-shaped bowl unit where formed at one end of the wedge unit where the cross section of the wedge unit is small   wherein the other end, where the cross section of the wedge unit is large, is separated from the wall, forming an air layer.   
   
   
       2 . The foam of  claim 1 , wherein the shape of the poroelastic acoustical foam is obtained using a topology optimization technique which is based on Biot's equation. 
   
   
       3 . The foam of  claim 2 , wherein material properties used in Biot's equation are interpolated in the form of a polynomial expression using design variables having values between zero and one. 
   
   
       4 . The foam of  claim 3 , wherein, when a design variable of zero indicates air, a design variable of one indicates a porous material, and a design variable having a value between zero and one indicates an intermediate material.