Search

EP-4311764-B1 - AERODYNAMIC STRUCTURE AND AIRCRAFT

EP4311764B1EP 4311764 B1EP4311764 B1EP 4311764B1EP-4311764-B1

Inventors

  • SEACK, OLIVER

Dates

Publication Date
20260506
Application Date
20220725

Claims (12)

  1. Aerodynamic structure (1), in particular for an aircraft (10), comprising a leading edge (2) having an outer structure, wherein the outer structure comprises: a first layer (3); and a second layer (4) geometrically corresponding to the first layer (3); wherein the first layer (3) is positioned on an outside (5) of the outer structure, the outside (5) being exposed to a flowing fluid, and the second layer (4) is positioned on an inside of the outer structure, wherein the second layer (4) comprises a material composition having an elongation at fracture in the range of 80 % to 200 %; wherein the second layer (4) has a higher ductility than the first layer (3) and a higher thermal and electrical conductivity than the first layer (3); and wherein the first layer (3) has a lower thickness than the second layer (4).
  2. Aerodynamic structure (1) according to claim 1, wherein the first layer (3) has a lower thickness than 0.5 mm, in particular the thickness of the first layer is in the range of about 0.2 to about 0.4 mm.
  3. Aerodynamic structure (1) according to one of the preceding claims, wherein the material of the first layer (3) consists of stainless steel, in particular the material of the first layer is selected from the group of carbon, nitrogen, aluminum, silicon, sulfur, titanium, nickel, copper, selenium, niobium and molybdenum.
  4. Aerodynamic structure (1) according to one of the preceding claims, wherein the material of the second layer (4) comprises aluminum or aluminum alloy.
  5. Aerodynamic structure (1) according to one of the preceding claims, wherein the material of the first layer (3) has a higher melting temperature than the material of the second layer (4), in particular the melting temperature of the material of the first layer is at least 300 °C higher than the melting temperature of the material of the second layer.
  6. Aerodynamic structure (1) according to one of the preceding claims, wherein the outer structure further comprises an ice-protection device, which is integrated into and/or attached to the second layer (4).
  7. Aerodynamic structure (1) according to one of the preceding claims, wherein the outer structure further comprises a third layer geometrically corresponding to the second layer (4) and positioned on an inner side of the second layer such that the outer structure is configured as a sandwich structure in the order first layer (3), second layer (4), third layer from the outside (5) to the inside.
  8. Aerodynamic structure (1) according to claim 7, wherein the third layer is made of a material, which has a similar or identical thermal expansion coefficient as the material of the first layer.
  9. Aerodynamic structure (1) according to claim 7 or 8, wherein the third layer is made of the same material as the first layer.
  10. Aerodynamic structure (1) according to one of the preceding claims, wherein the outer structure is manufactured by a metal coating process, in particular by cold or hot rolling, by flame spraying, by sputtering or by physical vapor deposition.
  11. Aerodynamic structure (1) according to one of the preceding claims, wherein the first layer (3) is sectional in contact with the second layer (4), in particular is completely in contact with the second layer.
  12. Aircraft (10) comprising an aerodynamic structure (1) according to one of the preceding claims.

Description

The invention relates to an aerodynamic structure. The invention is furthermore concerned with an aircraft containing such an aerodynamic structure. The leading edges of aerodynamic surfaces are exposed to a number of adverse effects like corrosion or erosion from dust, rain, snow and hail, impacts from birds, hail, ground vehicles and tool drops, lightning strikes and heat from ice-protection systems. Furthermore, the leading edges of aerodynamic surfaces have also to withstand high aerodynamic loads, as airflows around an aerodynamic surface develop high pressure peaks at their leading edges. All these effects result in a list of requirements, which demand partially contradicting technical solutions. Some of the technical solutions contain the placement of temporary protection against erosion, but that represents significant costs for the user. Currently, most of the aerodynamic surfaces of leading edges of today's passenger aircrafts are made from monolithic metals. For example, wing leading edge devices used for slow flight during take-off and landing, so-called slats, are typically made from aluminum alloys. Inlets of engine nacelles are made from aluminum too, but also from steel. The currently used material types offer in general good properties with respect to either structural strength, or resistance against erosion protection, thermal conductivity for thermal ice protection systems, surface smoothness, long-term optical appearance or manufacturability. Today, there is a need for a solution that reduces corrosion/erosion effects and that would also withstand high aerodynamic loads. Document GB833675A discloses a de-icing or anti-icing apparatus for an insulating surface, e.g. an aircraft wing, which comprises a metallic resistance layer which is applied direct to the surface by hot metal spraying, an insulating layer of thermo-setting plastic material also applied by hot spraying, and an outer metallic layer consisting of an undercoating, e.g. of aluminium, copper, or a synthetic resin intermixed with conductive particles such as silver flakes, and an electro-deposited top layer of relatively hard metal, e.g. of nickel or stainless steel. Aspects of the invention may provide solutions for reducing harmful effects on leading edges. According to the invention, this problem is solved by the subject-matter of the independent claim 1. According to a first aspect of the invention, an aerodynamic structure comprising a leading edge having an outer structure is provided. The outer structure comprises a first layer and a second layer geometrically corresponding to the first layer. Thereby the first layer is positioned on an outside of the outer structure, the outside being exposed to a flowing fluid, and the second layer is positioned on an inside of the outer structure. The second layer material comprises a material composition having an elongation at fracture in the range of 80 % to 200 %. Furthermore, the second layer has a higher ductility than the first layer and a higher thermal and electrical conductivity than the first layer, and the first layer has a lower thickness than the second layer. In particular, an aerodynamic structure for an aircraft is provided. According to a second aspect of the invention, an aircraft comprising an aerodynamic structure according to the invention is provided. A fundamental concept of the invention is to providing the multilayer outer structure combining at least two different materials, wherein the different materials are combined such that each layer and material, respectively, is composed to have advantageous specific properties with respect to structural strength, resistance against erosion, thermal conductivity, surface smoothness, long-term optical appearance and manufacturability. Thereby, the combination of the specific properties of each layer and material, respectively, when assembled as the multilayer outer structure has in total more advantages for the aerodynamic structure comprising a leading edge than using a monolithic metal for the leading edge. Moreover, the first layer and the second layer geometrically correspond to each other, that means the shape of the first layer is substantially the same as the shape of the second layer. In addition, the first layer material may include, for example, a material composition having an elongation at fracture less than or equal to 50 %, in particular less than or equal to 35 % in a solid state. Alternatively or additionally, the second layer material may, for example, comprise a material composition having an elongation at fracture in the range of 120 % to 180 % in a solid state. A higher ductility in the sense of the present invention is present, for example, if the elongations at fracture of the materials to be compared, i.e. the first layer material compared to the second layer material, differ by at least 10 % points. Elongation at break is a characteristic value in materials science that indicates the permanent