Lisi Aerospace

Hi-shear Corporation

Laurent Bourges

Johan Stephan

Christophe Van Daele

Christian Fauchet

Haikhanh Pham

Christophe Vandaele

Haikhanh Dao Pham

A metal component made of a base metal and a coating system thereon is characterized in that the coating system comprises a conductive layer on the base metal and a resin-based layer including conductive pigments on the conductive layer. The conductive pigments form electrically conductive 3D-networks in the resin, with the networks being randomly distributed in the resin. Further, a method for coating a metal component is disclosed, and may include depositing a conductive layer on a surface of the component, depositing a resin with electrically conductive pigments on the conductive layer and drying the resin. The coating system may be applied to metal components, including aerospace fasteners such as pins, bolts, collars, nuts and nut plates, and washers, as well as studs, latches, helicopter rotors, and landing gear structures.

Methods for coating and components having coatings for electrical conductivity

The invention relates to a method for installing metallic fastener () for the interference fit assembly of at least two structural elements () comprising a through hole, the fastener comprising an enlarged head (), a shaft () having an external diameter before installation that is greater than an internal diameter of the hole, said shaft comprising a conductive surface (). Before installation, at least the conductive surface () is coated with a lubricating layer (), which comprises a mixture of at least one polyolefin and one polytetrafluoroethylene, for example, having sufficient adherence to prevent its abrasion by manual manipulation of the fastener and being weak enough to be at least partly stripped from the conductive surface during the interference fit assembly of the fastener. The invention is applicable to the assembly of aircraft structures.

Fastener using lubricated interference fit

The invention relates to a metallic fastener () for the interference fit assembly of at least two structural elements () comprising a through hole, the fastener comprising an enlarged head (), a shaft () having an external diameter before installation that is greater than an internal diameter of the hole, said shaft comprising a conductive surface (). Before installation, at least the conductive surface () is coated with a lubricating layer (), which comprises a mixture of at least one polyolefin and one polytetrafluoroethylene, for example, having sufficient adherence to prevent its abrasion by manual manipulation of the fastener and being weak enough to be at least partly stripped from the conductive surface during the interference fit assembly of the fastener. The invention further relates to a method for obtaining such a fastener and to a method for installing such a fastener in a structure. The invention is applicable to the assembly of aircraft structures.

A method for locking a nut with an inner thread, in which the ultimate tensile strength (Rm) and yield strength (Re) of the material constituting the nut are determined according to temperature. An optimal heating temperature is determined, at which a maximum of a relative plastic interval of the material is reached, said relative plastic interval being defined by the formula (Rm&#x2212;Re)/Rm, and a maximum heating time is determined, above which the nut presents the risk of deterioration of its microstructure and/or of its initial mechanical strength. The nut is heated to a temperature substantially equal to said optimal temperature and for a heating time of less than said maximum time so that the initial microstructure and mechanical strength of the material constituting the nut are preserved, and a body of the nut is deformed locally by bending.

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Rancho Palos Verdes, CA, United States of America

Laurent Bourges