# US 8,770,343 B2 · Noise reduction system for composite structures > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,343 B2 - Document ID: US8770343B2 - Status: Granted - Kind: B2 - Application number: 13/303,294 - Filed: 2011-11-23 - Published: 2013-05-23 - Granted: 2014-07-08 - Earliest claimed: 2011-11-23 - Assignees: The Boeing Company - Applicants: Gopal Prasad Mathur; Cliff L. Chin - Inventors: Gopal Prasad Mathur; Cliff L. Chin - Web page: https://patentgrep.com/patent/US8770343B2 ## CPC - E04B 1/82: specifically with respect to sound only ({of floors or ceilings E04B9/001;} noise damping in ducts or channels E04F17/00; noise damping in general G10K11/16) - B32B 3/12: characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure - B64C 1/066: {Interior liners} - B64C 1/40: Sound or heat insulation {, e.g. using insulation blankets} - E04B 1/86: slab-shaped - G10K 11/172: using resonance effects - Y02T 50/40: Weight reduction - Y10T 428/24149: Honeycomb-like - E04B: GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS (border constructions of opening in walls, floors or ceilings E06B1/00; {electromagnetic shielding H05K9/0001}) - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - B64C: AEROPLANES; HELICOPTERS - G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method and apparatus comprising a composite panel and a number of structures to reduce noise radiation from the composite panel. The composite panel has a first face sheet, a second face sheet, and a core located between the first face sheet and the second face sheet. The number of structures is associated with the first face sheet. The number of structures has a mass with a configuration to reduce a speed of waves propagating in the composite panel such that noise radiating from the composite panel is reduced. ## Claims ### Claim 1 An apparatus comprising: a composite panel having a first face sheet, a second face sheet, and a core located between the first face sheet and the second face sheet; and a number of structures associated with the first face sheet, the number of structures having a mass with a configuration to reduce a speed of waves propagating in the composite panel such that noise radiating from the composite panel is reduced, the number of structures comprising a number of patches attached to an inner surface of the first face sheet, the core including a number of voids, the number of patches located in the number of voids, and the number of voids and the number of patches configured to provide gaps between the number of patches and the core. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the number of structures is configured to reduce the speed of the waves to less than about a speed of sound. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the core comprises a honeycomb. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the patches comprise elongate members. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the patches comprise a shape selected from one of a cube, a cylinder, a sphere, a pyramid, or a cuboid. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the composite panel is disposed in one of a wall, a ceiling, or a floor, of an aircraft. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the number of voids are closed with respect to the core. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the number of voids comprise a number of channels in a honeycomb structure of the core. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the core comprises a material selected from one of paper, plastic, foam, a meta aramid material, and a para aramid material. ### Claim 10 A method for reducing noise radiation from a composite panel, the method comprising: causing waves to propagate through the composite panel comprising a first face sheet, a second face sheet, and a core located between the first face sheet and the second face sheet; and reducing a speed of the waves propagating through the composite panel with a number of structures associated with the first face sheet, the number of structures having a mass with a configuration to reduce the speed of the waves propagating in the composite panel such that the noise radiating from the composite panel is reduced, the number of structures comprising a number of elongate members having the mass, the number of elongate members attached to an inner surface of the first face sheet and further comprising a number of voids in the core, the number of elongate members located in the number of voids in the core and the number of voids and number of elongate members configured to provide a number of gaps between the number of elongate members and the core. ### Claim 11 (depends on 10) The method of claim 10, wherein a second number of structures is associated with the second face sheet. ### Claim 12 (depends on 10) The method of claim 10, wherein the number of structures reduces the speed of the waves to less than about a speed of sound. ### Claim 13 (depends on 10) The method of claim 10 further comprising installing the composite panel in an aircraft. ### Claim 14 (depends on 10) The method of claim 10 further comprising reducing the speed of a shear wave through the composite panel.