Aeronautics and astronautics – Miscellaneous
Patent
1993-01-12
1995-05-23
Barefoot, Galen L.
Aeronautics and astronautics
Miscellaneous
361218, 244119, B64D 4502
Patent
active
054173850
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to structural components and is particularly although not exclusively concerned with structural components which are manufactured from composite materials and which are used as aircraft surface structures for the airframe and for engine nacelles.
Aircraft flying in and around thunderstorms are often subject to direct lightning strikes, which can produce severe damage, depending on the intensity of the strike and the construction of the structural component affected.
Electrical currents induced into the structural component create voltage differences and electromagnetic fields, which induce transient voltages and currents in systems wiring and hardware shielded by the component. This is particularly damaging in an aircraft engine environment where, on modern aircraft, engines are electronically controlled.
An aim therefore is to provide a structural component which will resist full penetration from a primary lightning strike, thereby protecting any electrical equipment shielded by it from the indirect effects of transient voltages and, by having a component free from overall penetration, against further adverse effects of high intensity radiated fields (HIRF).
With modern aircraft, where composite materials in which carbon or graphite fibres are used, the difficulty of providing equivalent protection when compared with an all metal structure are magnified due to the lower electrical conductivity of the carbon or graphite.
The various airworthiness certification authorities lay down standards to which aircraft manufactures must comply. Based on the probability of a lightning strike and the probable intensity of the lightning current generated in the strike, the authorities designate different potential strike zones for each aircraft and the probable current waveforms to which structures and systems in these zones must be resistant. These are identified as Zones 1A and 1B, Zones 2A and 2B and Zone 3 and current components A, B, C and D. The zones have been defined as follows:
Zone 1A - All areas of the aircraft surfaces where there is a high possibility of an initial lightning attachment with a low possibility of flash hang-on.
Zone 1B - All areas of the aircraft surfaces where there is a high possibility of an initial lightning attachment and a high possibility of flash hang-on.
Zone 2A - All areas of the aircraft surfaces where there is a high possibility of a lightning attachment being swept on to the area from a Zone 1A but having a low possibility of flash hang-on.
Zone 2B - All areas of the aircraft surface where there is a high possibility of a lightning attachment being swept on to the area from a Zone 1A but having a high possibility of flash hang-on.
Those surfaces not in zones 1 and 2 are said to be in Zone 3 where there is a low possibility of any attachment of the lightning channel. Zone 3 includes those portions of the aircraft which lie within, beneath, or between the other zones and which conduct substantial amounts of electrical current between direct or swept-stroke attachment points.
The location of strike zones on any aircraft is dependent on the geometry of the aircraft and operational factors, and often varies from one aircraft to another.
The four current components (A, B, C and D) are specified to determine direct effects under tests. Components A, B, C and D each simulate a different characteristic of the current in a natural lightning strike. Component A is a first return stroke current, component B is an intermediate current, component C is a continuing current, and component D is a restrike current.
It is an object of the present invention to provide a structural component which can be manufactured at least in part from composite materials and which provides improved zone 1A current component A and current component D protection.
It is a further object of the present invention to provide a structural component which can be manufactured at least in part from carbon, graphite or aramid fibre reinforced composite materials but which does not suffer from t
REFERENCES:
patent: 4198454 (1980-04-01), Norton
patent: 4349859 (1982-09-01), Sanders
patent: 4402779 (1983-09-01), Levy
patent: 4542056 (1985-09-01), Anglin et al.
patent: 4599255 (1986-07-01), Anglin et al.
patent: 4767656 (1988-08-01), Chee et al.
patent: 4888451 (1989-12-01), Toni et al.
patent: 5127601 (1992-07-01), Schroeder
Arnold Michael J.
Douglas Charles E.
Hamill Arthur B.
Barefoot Galen L.
Short Brothers PLC
LandOfFree
Structural component does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Structural component, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structural component will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2135407