摘要:
A space vehicle (1), in particular a satellite or a probe, capable of executing high-thrust maneuvers or high specific impulse maneuvers. According to the invention, the space vehicle (1) includes at least one solid-propellant chemical thruster (10-14) and at least one electric thruster (20-24).
摘要:
A part including a substrate in which at least a portion adjacent to a surface of the substrate is made of a refractory material containing silicon, is protected by an environmental barrier formed on the surface of the substrate and having at least a self-healing layer containing a rare earth silicate. The self-healing layer is formed: for at least 90 mol %, by a system constituted by 30 mol % to at most 80 mol % of at least one rare earth silicate RE2Si2O7, RE being a rare earth, and at least 20 mol % to 70 mol % of manganese oxide MnO; and for at most 10 mol %, by one or more oxides other than MnO, having a eutectic point with SiO2 less than or equal to 1595° C.; the self-healing layer presenting a liquid phase having a self-healing function at least throughout the temperature range 1200° C. to 1400° C., while conserving a majority solid phase.
摘要:
A method of fabricating a composite material casing for a gas turbine engine, the method including making an outer shroud including a platform and a flange, making an inner shroud of smaller diameter than the outer shroud and including a platform and a flange, making a plurality of casing arms, each including a blade that is terminated at each radial end by a respective platform, arranging a plurality of openings in the respective platforms of the shrouds, each opening serving to receive a platform of a casing arm, and assembling the casing arms with the outer shroud and with the inner shroud by inserting the platforms of the casing arms in the openings of the shrouds. A composite material casing is obtained by such a method.
摘要:
A method for obtaining solutions that contain 1,2,4-triazole-5-one (OTA) in concentrated sulphuric acid, includes using 3-amino-1,2,4-triazole (ATA) as a precursor of OTA. There is also provided a method for preparing 3-nitro-1,2,4-triazole-5-one (4) (ONTA) from the solutions.
摘要:
A part made of ceramic matrix composite material has fiber reinforcement of carbon or ceramic fibers and a majority-ceramic sequenced matrix having first matrix layers made of crack-deflector material alternating with second matrix layers made of ceramic material. An interphase coating is interposed between the fibers and the matrix, and the interphase coating adheres to the fibers and to the matrix, and is formed of at least one sequence constituted by a first elementary layer made of carbon, possibly doped with boron, surmounted by a second elementary layer made of ceramic. The outer elementary interphase layer of the coating is a ceramic layer having an outer surface formed by ceramic grains of size lying essentially in the range 20 nm to 200 nm, with the presence of grains of size greater than 50 nm conferring roughness on the outer surface ensuring mechanical attachment with the adjacent matrix phase.
摘要:
A part made of oxide/oxide composite material includes fiber reinforcement constituted by a plurality of warp yarn layers and of weft yarn layers interlinked by three-dimensional weaving, with the spaces present between the reinforcing yarns being filled with a refractory oxide matrix. The fiber reinforcement presents a weave selected from the following weaves: interlock; multi-plain; multi-satin; and multi-serge, with warp and weft thread counts lying in the range 4 yarns/cm to 20 yarns/cm. The fiber reinforcement also presents a fiber volume fraction lying in the range 40% to 51%.
摘要:
A method for fabricating turbine engine blade or vane made of composite material includes: performing three-dimensional weaving to make a single-piece fiber blank; shaping the fiber blank to obtain a single-piece fiber preform having a first portion forming a preform for at least a blade/vane airfoil, at least one second portion forming a preform for an inner part of a blade/vane inner platform or for an outer part of a blade/vane outer platform, and at least one third portion forming a preform for an outer part of a blade/vane inner platform or for an inner part of a blade/vane outer platform; and densifying the fiber preform with a matrix to obtain a composite material blade, and forming a single piece with an inner and/or outer platform(s) incorporated therein.
摘要:
A paste kneading device includes an oblong barrel, two shafts arranged parallel within the barrel, being held and driven at their first ends, defining an upstream end, by a drive device, two screws each formed by threads carried by the shafts, each screw having a transport section carrying a main thread to cause the paste to advance along the two screws, and an outlet orifice formed in the wall of the barrel to discharge the kneaded paste, the kneading device further including a holder device to hold each shaft at its second end, defining a downstream end, and enabling the shaft to rotate freely, the holder device including, for each shaft, a first portion secured to the shaft and a second portion secured to a cap end portion of the barrel, the cap end portion being removable and the first and second portions being configured to engage and disengage freely.
摘要:
A normally closed electric switch having a sliding assembly that is actuated to open the switch, e.g. by a pyrotechnic gas generator. Prior to actuation, a conductive portion of the sliding assembly (21) is in tight contact with two rings (13a, 14a) that are axially offset on the same axis, belonging respectively to two electrically conductive tabs (13, 14), and after the actuator has been triggered, the upstream tab (13) is separated from the conductive portion of the sliding assembly. According to the invention, sliding assembly comprises a tube split by a slot extending along its entire length, and the conductive portion of the sliding assembly is constituted by all or part of said split tube, the clamping force between the conductive portion and the primary electrically conductive tabs being provided by the resilience of the split tube.
摘要:
A device for monitoring a viscoelastic material by subjecting the sample to vibration and analyzing the response of the sample to such vibration. According to the invention, the sample (13) is placed in a chamber (20) situated between a vibration source (22) and a vibration sensor (25), these elements being pressed towards each other by means (35, 39) for applying initial mechanical loading.