Abstract: A part made of a fiber-reinforced composite material includes a structure made from a set of fibers supported in a thermosetting resin and a peel ply across all or part of the outer surface of the structure. The part has a gradient of polymerization at the interface between the structure and the peel ply. Also, methods for making such a part and methods for bonding such parts.

Abstract: A device for protecting an airfoil element made of a complex comprising a polymer film, a metal strip deposited on a part of the polymer film and an adhesive element to attach the polymer film on the airfoil element. The polymer film forms a protection against sand abrasion. The metal strip forms a protection against water abrasion of the airfoil element on which the complex is attached.

Abstract: A drill bit having an interior canal for liquid nitrogen to pass longitudinally through the body of the drill bit. The canal has, on the side of a cutting edge of the drill bit, at least one liquid nitrogen ejection duct that opens near the cutting edge which is formed by an insert made with polycrystalline diamond fixed to the body of the drill bit. A device for drilling a metal-composite stack includes the drill bit, a liquid nitrogen production unit and a distribution network to distribute the liquid nitrogen. The device drills through a metal-composite stack in a single pass of the drill bit. The liquid nitrogen at cryogenic temperature is conveyed close to the cutting edge, at least while the cutting edge is in contact with the metallic material.

Abstract: A method for repairing a defect affecting a weld. A sheet of filler metal is placed on the surface of the welded part, next to the region of the defect. The sheet is locally welded to the welded part in the region of the defect using a friction stir welding tool having a retractable welding pin. The welded part and the sheet are separated such that the filler metal amalgamated with the metal of the welded part remains in position. The local welding operation includes successively performing the following: setting the welding tool into rotation and putting it under pressure; inserting the pin to a small distance from the anvil while maintaining or increasing the pressure on the shoulder of the welding tool; progressively retracting the pin while maintaining or increasing the pressure on the shoulder; and stopping the pressure on the shoulder when the retractable pin has been retracted.

Abstract: A part made of a fiber-reinforced composite material includes a structure made from a set of fibers supported in a thermosetting resin and a peel ply across all or part of the outer surface of the structure. The part has a gradient of polymerization at the interface between the structure and the peel ply. Also, methods for making such a part and methods for bonding such parts.

Abstract: A method for drilling through an assembly forming a stack of at least two different materials uses a drill bit having at least a first cutting edge and a second cutting edge inclined in an axial plane of the drill bit so that the end of the drill bit has a projecting conical shape. The first cutting edge is configured to drill a first material. The second cutting edge is made differently from the first cutting edge, to drill a second material. A first rotational drive axis of the drill bit is laterally offset during the drilling by an offset distance D relative to the axis of the drill bit in a direction opposite the first cutting edge when the drill bit is drilling through the first material, and alternately, in a direction opposite the second cutting edge when the drill bit is drilling through the second material.

Abstract: A drill bit having an interior canal for liquid nitrogen to pass longitudinally through the body of the drill bit. The canal has, on the side of a cutting edge of the drill bit, at least one liquid nitrogen ejection duct that opens near the cutting edge which is formed by an insert made with polycrystalline diamond fixed to the body of the drill bit. A device for drilling a metal-composite stack includes the drill bit, a liquid nitrogen production unit and a distribution network to distribute the liquid nitrogen. The device drills through a metal-composite stack in a single pass of the drill bit. The liquid nitrogen at cryogenic temperature is conveyed close to the cutting edge, at least while the cutting edge is in contact with the metallic material.

Abstract: A method for repairing a defect affecting a weld. A sheet of filler metal is placed on the surface of the welded part, next to the region of the defect. The sheet is locally welded to the welded part in the region of the defect using a friction stir welding tool having a retractable welding pin. The welded part and the sheet are separated such that the filler metal amalgamated with the metal of the welded part remains in position. The local welding operation includes successively performing the following: setting the welding tool into rotation and putting it under pressure; inserting the pin to a small distance from the anvil while maintaining or increasing the pressure on the shoulder of the welding tool; progressively retracting the pin while maintaining or increasing the pressure on the shoulder; and stopping the pressure on the shoulder when the retractable pin has been retracted.

Abstract: A method for drilling through an assembly forming a stack of at least two different materials uses a drill bit having at least a first cutting edge and a second cutting edge inclined in an axial plane of the drill bit so that the end of the drill bit has a projecting conical shape. The first cutting edge is configured to drill a first material. The second cutting edge is made differently from the first cutting edge, to drill a second material. A first rotational drive axis of the drill bit is laterally offset during the drilling by an offset distance D relative to the axis of the drill bit in a direction opposite the first cutting edge when the drill bit is drilling through the first material, and alternately, in a direction opposite the second cutting edge when the drill bit is drilling through the second material.

Abstract: A device for protecting an airfoil element made of a complex comprising a polymer film, a metal strip deposited on a part of the polymer film and an adhesive element to attach the polymer film on the airfoil element. The polymer film forms a protection against sand abrasion. The metal strip forms a protection against water abrasion of the airfoil element on which the complex is attached.

Abstract: A drill bit having an interior canal for liquid nitrogen to pass longitudinally through the body of the drill bit. The canal has, on the side of a cutting edge of the drill bit, at least one liquid nitrogen ejection duct that opens near the cutting edge which is formed by an insert made with polycrystalline diamond fixed to the body of the drill bit. A device for drilling a metal-composite stack includes the drill bit, a liquid nitrogen production unit and a distribution network to distribute the liquid nitrogen. The device drills through a metal-composite stack in a single pass of the drill bit. The liquid nitrogen at cryogenic temperature is conveyed close to the cutting edge, at least while the cutting edge is in contact with the metallic material.

Abstract: An inertia wheel including a storage ring and a hub connecting the storage ring to a rotation shaft of the wheel, the hub including a central part forming a hub body for connecting to the shaft, a peripheral part forming a rim for connecting to the storage ring and an intermediate part formed by a disk between the hub body and the rim. The hub is made from a composite material and includes a module having a stiffness that decreases from the hub body to the rim. A method for producing such an inertia wheel is also provided.

Abstract: A part (1) includes a structural portion made of an electrically insulating or low-conductive composite material (2) and includes, on a surface (11) of the structural portion likely to be subjected to lightning impacts (10), a metallization layer (30) covered with an electrically insulating protection paint (4). The metallization layer includes a layer of a first electrically conductive metal material (31), referred to as HVT material, and includes at least one second electrically conductive metal material (32), referred to as LVT material, having a vaporization temperature ?l substantially lower than the vaporization temperature ?h of the first electrically conductive HVT metal material. A lightning impact results in the vaporization of the LVT material and the removal of the paint on a surface larger than that in which the HVT material is vaporized, and therefore exposes or lifts a portion of the metallization around the lightning impact point, thereby promoting the anchoring of the lightning arc base.

Abstract: The invention relates to a part (11) made of a composite formed from a thermosetting resin, which includes lightning protection element including, on an upper surface (12) of the part (11) liable to be exposed to lightning strikes, a continuous layer of a metal foil (1) having perforations (2) with a degree of perforation between 0.005% and 20%.

Abstract: The invention relates to a double shouldered welding device for the friction stir welding of parts, in which at least one shoulder has two concentric rings providing two plane concentric bearing surfaces, the rings being arranged so that the smaller-diameter ring is capable of compressing the stirred material of the parts to be welded during advance of the welding device and so that the larger-diameter ring is capable of forming a sink-in stop for the smaller-diameter ring. The invention also relates to a method of friction stir welding by means of the welding device according to the invention, in which said device is force-driven.

Abstract: The invention relates to a double shouldered welding device for the friction stir welding of parts, in which at least one shoulder has two concentric rings providing two plane concentric bearing surfaces, the rings being arranged so that the smaller-diameter ring is capable of compressing the stirred material of the parts to be welded during advance of the welding device and so that the larger-diameter ring is capable of forming a sink-in stop for the smaller-diameter ring. The invention also relates to a method of friction stir welding by means of the welding device according to the invention, in which said device is force-driven.

Abstract: An omnidirectional video camera captures images of the environment while moving along several intersecting paths forming an irregular grid. These paths define the boundaries of a set of image loops within the environment. For arbitrary viewpoints within each image loop, a 4D plenoptic function may be reconstructed from the group of images captured at the loop boundary. For an observer viewpoint, a strip of pixels is extracted from an image in the loop in front of the observer and paired with a strip of pixels extracted from another image on the opposite side of the image loop. A new image is generated for an observer viewpoint by warping pairs of such strips of pixels according to the 4D plenoptic function, blending each pair, and then stitching the resulting strips of pixels together.