Cell structure for use in an acoustic panel, and methods of producing the same
An improved cell structure that enables design improvements to acoustic panels is provided. The provided cell structure for an acoustic panel is (i) capable of damping a wider range of audible frequencies, (ii) able to be easily combined and integrated into a variety of panel dimensions, and (iii) manufacturable using additive manufacturing techniques such as direct metal laser sintering (DMLS).
1. A cell structure for use in an acoustic panel, the cell structure comprising:
a cavity enclosed by a continuous boundary wall, the boundary wall (i) having a central axis, (ii) having a regular shaped cross section perpendicular to the central axis, (iii) having a floor side and an entrance side, (iv) the entrance side separated from the floor side by a first height;
a support structure arranged in the cavity;
a chamber suspended within the cavity by the support structure, the chamber being coaxial with the boundary wall and axisymmetric around the central axis, the chamber being closed on the entrance side and open on the floor side wherein a maximum cross sectional area of the floor side of the chamber is approximately 50% of a maximum cross sectional area of the cell structure; wherein a maximum cross sectional area of the entrance side of the chamber is approximately 10% of the maximum cross sectional area of the cell structure; wherein the boundary wall, support structure, and the chamber, are fabricated using an additive manufacturing process; and wherein the support structure comprises a tunable spring beam attached on a first end to the chamber and attached on a second end to the floor side.
2. The cell structure of claim 1 , wherein the tunable spring beam is one of three tunable spring beams, each attached on a first end to the chamber and attached on a second end to the floor side, the three tunable spring beams separated radially around the central axis by approximately 120 degrees.
3. The cell structure of claim 1 , wherein an opening in the floor side comprises approximately 30% of the cross sectional area of the floor side.
4. The cell structure of claim 1 , wherein the boundary wall is perforated.
5. The cell structure of claim 1 , further comprising a cell structure ceiling with a through hole.
6. An additively manufactured acoustic panel, the acoustic panel comprising:
a plurality of integrally joined cell structures, each cell structure of the plurality of cell structures having the same entrance side and the same floor side, each cell structure of the plurality of cell structures comprising
(a) a cavity enclosed by a continuous boundary wall, the boundary wall (i) having a central axis, (ii) having a regular shaped cross section perpendicular to the central axis, (iii) having a floor side and an entrance side, (iv) the entrance side separated from the floor side by a first height;
(b) a support structure arranged in the cavity;
(c) a chamber suspended within the cavity by the support structure, the chamber being coaxial with the boundary wall and axisymmetric around the central axis, the chamber being closed on the entrance side and open on the floor side; wherein a maximum cross sectional area of the floor side of each chamber is approximately 50% of a maximum cross sectional area of the respective cell structure; wherein a maximum cross sectional area of the entrance side of each chamber is approximately 10% of the maximum cross sectional area of the respective cell structure; and wherein, for each cell structure, each support structure comprises a tunable spring beam attached on a first end to the respective chamber and attached on a second end to the respective floor side.
7. The acoustic panel of claim 6 , wherein, for each cell structure, the tunable spring beam is one of three tunable spring beams, each attached on a first end to the chamber and attached on a second end to the floor side, the three tunable spring beams separated radially around the central axis by approximately 120 degrees.
8. The acoustic panel of claim 6 , wherein, for each cell structure, an opening in the floor side comprises approximately 30% of the cross sectional area of the respective floor side.
9. The acoustic panel of claim 7 , wherein, for each cell structure, an opening in the floor side comprises approximately 30% of the cross sectional area of the respective floor side.
10. A method for manufacturing a cell structure for an acoustic panel, the method comprising:
creating a cavity with a central axis, a regular shaped cross section perpendicular to the central axis, a floor side, and an entrance side, with a continuous boundary wall;
arranging a support structure in the cavity;
using the support structure to suspend a chamber within the cavity, the chamber being coaxial with the boundary wall and axisymmetric around the central axis, the chamber being closed on the entrance side and open on the floor side;
wherein a maximum cross sectional area of the floor side of the chamber is approximately 50% of a maximum cross sectional area of the cell structure, and a maximum cross sectional area of the entrance side of the chamber is approximately 10% of the maximum cross sectional area of the cell structure; and wherein the support structure comprises a tunable spring beam attached on a first end to the chamber and attached on a second end to the floor side.
11. The method of claim 10 , further comprising, covering the entrance side of the cavity with a cell structure ceiling having a through-hole therein.