Anti-resonant panel and methods of making the same

1. An anti-resonant panel comprising:

a base panel comprising a base panel core material and two base panel face sheets, each of the two base panel face sheets adjacent to an opposite side of the base panel core material; and

at least one stiffener-member disposed on one of the two base panel face sheets in a defined area of the base panel, the defined area being less than a full area of the base panel,

wherein the at least one stiffener-member comprises a stiffener-member core material and two stiffener-member face sheets, the stiffener-member face sheets are each adjacent to an opposite side of the stiffener-member core material.

2. The anti-resonant panel according to claim 1 , wherein the at least one stiffener-member is configured to provide anti-resonant performance to the base panel by adding stiffness to the defined area of the base panel at a low mass density.

3. The anti-resonant panel according to claim 1 , wherein the at least one stiffener-member is disposed between the two base panel face sheets and adjacent to the base panel core material.

4. The anti-resonant panel according to claim 1 , wherein the at least one stiffener-member is disposed along less than 25% of a total surface area of the base panel and a mass of the at least one stiffener-member is about 20% or less of a total mass of the anti-resonant panel.

5. The anti-resonant panel according to claim 1 , wherein the at least one stiffener-member comprises two or more stiffener-members each positioned along the base panel in respective defined areas of the base panel.

6. The anti-resonant panel according to claim 1 , wherein the stiffener-member core material comprises polyethylene terephthalate foam, aramid honeycomb construction, or combinations thereof.

7. The anti-resonant panel according to claim 1 , wherein the stiffener-member face sheets comprise carbon fiber, fiberglass, a fiber composite, or combinations thereof.

8. The anti-resonant panel according to claim 1 , wherein the anti-resonant panel is configured to reduce noise propagation through the anti-resonant panel at frequencies between about 300 Hz to about 1000 Hz.

9. The anti-resonant panel according to claim 1 , further comprising a perimeter-type stiffener-member disposed along one or more edges of the at least one stiffener-member.

10. The anti-resonant panel according to claim 1 , wherein the at least one stiffener-member comprises an interior wall defining a hollowed portion in the at least one stiffener-member.

11. An anti-resonant panel comprising:

a base panel comprising a base panel core material and two base panel face sheets, each of the two base panel face sheets adjacent to an opposite side of the base panel core material;

at least one stiffener-member positioned along the base panel in a defined area of the base panel, the defined area being less than a full area of the base panel; and

at least one inertial member, the at least one inertial member configured to provide a mass increase over the defined area of the anti-resonant panel,

wherein the at least one stiffener-member comprises a stiffener-member core material and two stiffener-member face sheets, the stiffener-member face sheets are each adjacent to an opposite side of the stiffener-member core material.

12. The anti-resonant panel according to claim 11 , wherein the at least one inertial member has a mass density of about 10 times a mass density of the at least one stiffener-member.

13. The anti-resonant panel according to claim 11 , wherein the at least one inertial member comprises solid aluminum, rubber, tungsten, ceramic, or a combination thereof.

14. The anti-resonant panel according to claim 1 , further comprising a reinforcing member, the reinforcing member disposed along a perimeter of the defined area of the base panel and defining an acoustic boundary for the defined area of the base panel.

15. The anti-resonant panel according to claim 1 , further comprising a grounding member, the grounding member configured to anchor the anti-resonant panel to a structure and define an acoustic boundary for the defined area of the base panel.

16. A method of making an anti-resonant panel having a base panel with a base panel core material and two base panel face sheets, each of the two base panel face sheets adjacent to an opposite side of the base panel core material, the method comprising:

attaching at least one stiffener-member to one of the two base panel face sheets in a defined area of the base panel, the at least one stiffener-member including a stiffener-member core material and two stiffener-member face sheets, each of the two stiffener-member face sheets adjacent to an opposite side of the stiffener-member core material, wherein the at least one stiffener-member is configured to provide anti-resonant performance to the base panel.

17. The method according to claim 16 , wherein attaching the at least one stiffener-member to the base panel comprises at least one of composite layup, hot-pressing, vacuum-forming, vacuum bagging, vacuum assisted resin transfer molding, or incorporating at least one of an attachment mechanism comprising a screw, adhesive, adhesive film, or rivet to attach the at least one stiffener-member to the base panel.

18. The method according to claim 16 , further comprising removing an interior portion of the at least one stiffener-member creating a hollowed portion in the at least one stiffener-member prior to attaching the at least one stiffener-member to the base panel.

19. The anti-resonant panel according to claim 11 , wherein the at least one stiffener-member is disposed on one of the two base panel face sheets.