Abstract: A fastener includes an elongated shaft having a first end, a second end, and a shaft body, a head portion, and a threaded portion. At least one inner feed channel extends through the head portion and the shaft body and terminates proximal to the threaded portion. The fastener has a plurality of flutes formed along and circumferentially spaced around an outer surface of the shaft body and an outer surface of the head portion. Each flute has a first end and extends from a first location proximal to the threaded portion, along the outer surface of the shaft body, and radially outward along the outer surface of the head portion. The fastener further has one or more lateral feed channels formed laterally through the shaft body and connecting the inner feed channel to at least two opposing flutes on the outer surface of the shaft body.

Abstract: An aircraft component incorporated in a current return network (CRN) employs a composite structural element having a web. At least one flange is connected to the web. At least one metallic conductive layer is integrated with and extends the length of the web. The at least one metallic layer is configured to electrically bond to an aircraft system and provide a ground path.

Abstract: A fastener for improved electrical contact with a composite structure and improved distribution of electric current to the composite structure. The fastener includes an elongated shaft having a first end with a head portion, a second end with a threaded portion, and a shaft body therebetween. At least one feed channel extends from an opening at the threaded portion, through the shaft body, and terminates proximal to the head portion. The shaft body radially expands upon pressure injection of a resin filler into the feed channel, when the fastener is installed in a corresponding fastener hole formed in the composite structure. Upon radially expanding, the outer surface of the shaft body makes contact with an inner hole surface of the corresponding fastener hole, resulting in the fastener providing electrical contact with the composite structure and providing distribution of electric current.

Abstract: A multilayer composite structure with integrated fastener-to-conductive layer surface lightning protection interconnection employs a conductive layer with an inner surface and a plurality of chamfered recesses forming countersinks in an outer surface. A carbon-fiber reinforced plastic (CFRP) composite layer is disposed on the inner surface of the conductive layer and conforms to the surface shape. A plurality of holes extend through the plurality of chamfered recesses in the conductive layer and the adjoining CFRP composite layer in a manner such that the conductive layer defines a countersink portion extending into the openings of the plurality of holes. The chamfered recesses in the conductive layer provides an electrically conductive surface area that contacts conductive countersunk fasteners installed within the plurality of holes to enable current sharing between groups of neighboring fasteners.

Abstract: An aircraft component incorporated in a current return network (CRN) employs a composite structural element having a web. At least one flange is connected to the web. At least one metallic conductive layer is integrated with and extends the length of the web. The at least one metallic layer is configured to electrically bond to an aircraft system and provide a ground path.

Abstract: A fastener for improved electrical contact with a composite structure and improved distribution of electric current to the composite structure. The fastener includes an elongated shaft having a first end with a head portion, a second end with a threaded portion, and a shaft body therebetween. At least one feed channel extends from an opening at the threaded portion, through the shaft body, and terminates proximal to the head portion. The shaft body radially expands upon pressure injection of a resin filler into the feed channel, when the fastener is installed in a corresponding fastener hole formed in the composite structure. Upon radially expanding, the outer surface of the shaft body makes contact with an inner hole surface of the corresponding fastener hole, resulting in the fastener providing electrical contact with the composite structure and providing distribution of electric current.

Abstract: A fastener includes an elongated shaft having a first end, a second end, and a shaft body, a head portion, and a threaded portion. At least one inner feed channel extends through the head portion and the shaft body and terminates proximal to the threaded portion. The fastener has a plurality of flutes formed along and circumferentially spaced around an outer surface of the shaft body and an outer surface of the head portion. Each flute has a first end and extends from a first location proximal to the threaded portion, along the outer surface of the shaft body, and radially outward along the outer surface of the head portion. The fastener further has one or more lateral feed channels formed laterally through the shaft body and connecting the inner feed channel to at least two opposing flutes on the outer surface of the shaft body.

Abstract: A multilayer composite structure with integrated fastener-to-conductive layer surface lightning protection interconnection employs a conductive layer with an inner surface and a plurality of chamfered recesses forming countersinks in an outer surface. A carbon-fiber reinforced plastic (CFRP) composite layer is disposed on the inner surface of the conductive layer and conforms to the surface shape. A plurality of holes extend through the plurality of chamfered recesses in the conductive layer and the adjoining CFRP composite layer in a manner such that the conductive layer defines a countersink portion extending into the openings of the plurality of holes. The chamfered recesses in the conductive layer provides an electrically conductive surface area that contacts conductive countersunk fasteners installed within the plurality of holes to enable current sharing between groups of neighboring fasteners.