Stress reducing holes
AssigneeSikorsky Aircraft Corporation
InventorsKrzysztof Kopanski, Justin Thomas
Life of this patent
Estimating the term…
Abstract
A blade includes a blade body having a surface and a hole extending through the surface of the blade body. The hole defines a hole axis and a plane perpendicular to the hole axis. The hole has an elongated hole perimeter within the plane. The hole perimeter includes a plurality of non-linear perimeter sections to minimize stress concentration around the elongated hole perimeter while maximizing the usable opening area. A rotor system includes a rotor hub and a blade as recited above. The blade extends radially outward from the rotor hub. The blade defines a root end proximate to the rotor hub, a tip end opposite the root end.
Claims13
A blade comprising:
- a blade body having a surface;
- and
- a hole extending through the surface of the blade body, wherein the hole defines a hole axis and a plane perpendicular to the hole axis, and wherein the hole has an elongated hole perimeter within the plane, wherein the hole perimeter includes a plurality of non-linear perimeter sections configured to minimize stress concentration around the elongated hole perimeter while maximizing the usable opening area,
- wherein the non-linear perimeter sections include:
- two spaced apart opposed parabolic conic sections, wherein each parabolic conic section includes a pair of endpoints and a vertex, wherein a centerline axis of the elongated hole perimeter extends between the vertices within the plane;
- and
- two spaced apart opposed circular arcs, wherein each circular arc includes a pair of endpoints, wherein one of the endpoints from each of the parabolic sections connects with respective endpoints of one of the circular arcs, and wherein the other endpoints from each of the parabolic sections connect with respective endpoints of the other circular arc.
Dependencies are inferred from the claim text.