Core matertal for balanced rotor blade

{
  "publication_number": "US11548627B2",
  "country": "US",
  "kind": "B2",
  "title": "Core matertal for balanced rotor blade",
  "abstract": "A method of forming a balanced rotor blade assembly includes measuring a weight of a plurality of sub-components of the rotor blade assembly excluding a core. A configuration of a core of the rotor blade assembly is determined. In combination, the core and the plurality of sub-components achieve a target weight distribution and moment. The core is then fabricated and assembled with the plurality of sub-components to form a rotor blade sub-assembly.",
  "claims": [
    "1. A method of forming a balanced sub-assembly of a rotor blade assembly comprising: measuring a weight of a plurality of sub-components of the rotor blade assembly excluding a core; determining, by a processor, responsive to the measured weight of the plurality of sub-components of the rotor blade assembly excluding the core, a configuration of a plurality of cells, based on a weight distribution of the plurality of sub-components, the plurality of cells including a first plurality of cells having a first density creating a first weight in a first area of the core and including a second plurality of cells having a second density creating a second weight in a second area of the core to form the core such that in combination the core having the first weight in the first area and the second weight in the second area and the plurality of sub-components achieve a target weight distribution and moment for the rotor blade assembly, each cell including a cell opening bounded by at least one cell wall; determining, by the processor, a first anticipated stress in the first area and a second anticipated stress in the second area, the second anticipated stress being lower than the first anticipated stress; fabricating, via an additive manufacturing process, the core based at least in part on the configuration of the plurality of cells determined by the processor and the first anticipated stress and the second anticipated stress determined by the processor, wherein (1) the second density is lower than the first density and (2) the core is a unitary core; and assembling the plurality of sub-components and the core to form a rotor blade sub-assembly having the target weight distribution and moment for the rotor blade assembly.",
    "2. The method according to claim 1, wherein at least one property of the core varies across at least one of a span, chord, and thickness of the rotor blade assembly.",
    "3. The method according to claim 1, wherein the core comprises a core panel.",
    "4. The method according to claim 1, wherein determining a configuration of the core further comprises: determining a weight distribution based of the plurality of sub-components; determining a weight distribution of the core necessary to achieve a target weight distribution and moment of the sub-assembly.",
    "5. The method according to claim 4, wherein determining a configuration of the core further comprises: determining at least one of a shape, density, wall thickness, and material of the core.",
    "6. The method according to claim 5, wherein the determined at least one of the shape, density, wall thickness, and material is based at least in part on the determined weight distribution based of the plurality of sub-components and the determined weight distribution of the core necessary to achieve a target weight distribution and moment of the sub-assembly.",
    "7. The method according to claim 1, wherein the configuration of the plurality of cells is determined by the processor based on the weight distribution and anticipated stresses of the rotor blade assembly.",
    "8. The method according to claim 1, wherein the core comprises a core panel, and the method further includes determining, by the processor, structural and dimensional requirements of the core panel.",
    "9. The method according to claim 1, further comprising: forming the plurality of cells, each cell including a cell opening bounded by at least one cell well, wherein at least one cell of the plurality of cells includes end flange connected to a cell wall.",
    "10. The method according to claim 1, wherein the core is fabricated fabricating the core adjacent to a plurality of integrated fastener locations respectively surrounded by reinforcement zones, the cells in direct contact with the reinforcement zones comprising curved cell walls, and each reinforcement zone in contact with at least one other reinforcement zone via a respective linear cell wall.",
    "11. The method according to claim 1, wherein the plurality of cells are hexagonal.",
    "12. The method according to claim 1, wherein the core comprises a core panel, the method further comprising: determining an optimized configuration of the core panel."
  ],
  "description_excerpt": "The subject matter disclosed herein generally relates to rotor blades, and more particularly to a method and apparatus for providing a properly balanced rotor blade.\n\nIn order to operate properly in a dynamic environment, the rotor blade on a rotary wing aircraft must be properly balanced to avoid an increased level of vibration. The rotor blades are typically manufactured using a plurality of components. As a result, the weight can vary between what are intended to be identically balanced blades.\n\nIn order for the rotor blades to perform properly, the weight distribution and the resultant moments of the blade must meet predetermined criteria which define target distribution and moments along the length or span of the blade from root to tip, and also chordally, from the leading edge to the trailing edge thereof. Achieving the predetermined weight distribution criteria will result in a “balanced” rotor blade that will operate properly for its intended application. Thus, each rotor blade must be individually checked for weight distribution and must be brought into balance. The conventional procedures for balancing a rotor blade assembly are time-consuming.\n\nIn one embodiment, a method of forming a balanced rotor blade sub-assembly includes measuring a weight of a plurality of sub-components of the rotor blade assembly excluding a core. A configuration of a core of the rotor blade assembly is determined. In combination, the core and the plurality of sub-components achieve a target weight distribution and moment. The core is then fabricated and assembled with the plurality of sub-components to form a rotor blade sub-assembly.",
  "cpc": [
    "B64C 27/008",
    "B29C 64/386",
    "B33Y 10/00",
    "B33Y 50/00",
    "B33Y 80/00",
    "B64C 2027/4736",
    "B64C 27/473",
    "F01D 5/027",
    "F03D 1/0675",
    "F03D 13/35",
    "F04D 29/662",
    "F05B 2230/60",
    "F05D 2250/283",
    "F05D 2260/15",
    "F05D 2260/81",
    "F16F 15/34",
    "G01M 1/14",
    "G01M 1/36",
    "Y02E 10/72",
    "Y02P 70/50",
    "Y02T 50/60"
  ],
  "ipc": [
    "B29C 64/386",
    "B33Y 10/00",
    "B33Y 50/00",
    "B33Y 80/00",
    "B64C 27/00",
    "B64C 27/473",
    "F01D 5/02",
    "F03D 1/06",
    "F03D 13/35",
    "F04D 29/66",
    "F16F 15/34",
    "G01M 1/14",
    "G01M 1/36"
  ],
  "assignees": [
    "Sikorsky Aircraft Corp"
  ],
  "inventors": [
    "Eric Cotton",
    "Aaron Daniels"
  ],
  "filing_date": "2017-08-04",
  "publication_date": "2023-01-10",
  "grant_date": "2023-01-10",
  "priority_date": "2016-08-15",
  "application_number": "US-201715669591-A",
  "family_id": "59683396",
  "cited_by_count": 3,
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}