Abstract: A car belonging to a rolling vehicle, characterized in that it includes sidewalls in the form of a single piece made from composite material including a sandwich structure provided with a first skin on the outside of the car, a second skin on the inside of the car and a closed-cell foam or honeycomb core between the skins, the walls being provided with window openings formed by interruptions in the drapes of longitudinal fibres, transverse fibres and intersecting diagonal fibres, the openings having a polygonal shape that reduces the surface area of interrupted diagonal fibres in the corners of the openings.

Abstract: A structure, made from composite materials for a vehicle chassis, being configured to receive an undercarriage at its ends and includes at least one central beam that includes a median box having a central part and two ends with a reinforced structure, and the central part includes a reinforced part increasing the strength of the beam with respect to the bending stresses imposed by the transported load. The median box is reinforced by two lateral boxes extending over the entire length of the median box), assembled to the median box, the upper faces of which, together with the upper face of the median box, form the upper face of the beam. The structure includes a floor that covers the upper faces of the median box and the lateral boxes. The elements making up the structure have shapes that are simple, easy to make from composite materials and easy to assemble.

Abstract: A device for assembling sections of wind-turbine blades provided with casings, including at least one tie including a first portion and a second portion, the first portion being a portion for assembly with a casing of a first section and the second portion being a portion for mounting with a complementary tie supported by a casing of a second section, wherein the first portion includes at least one composite/metal shear link provided with a continuous fitting element on at least one surface of the casing which receives one end of the aformentioned surface of the casing, provided with attachment pins passing through the fitting and the end of the surface.

Abstract: A method of making a mechanical multishear link includes sizing the multishear link by breaking down a system comprised by the link into as many subassemblies as there are simple shear interfaces, defining the subassemblies around each shear interface, describing each shear by its stiffness, and applying the mechanical relationships to achieve a system of equations for a computer-assisted resolution by applying the Huth method to each shear interface.

Abstract: A device for assembling sections of wind-turbine blades provided with casings, including at least one tie including a first portion and a second portion, the first portion being a portion for assembly with a casing of a first section and the second portion being a portion for mounting with a complementary tie supported by a casing of a second section, wherein the first portion includes at least one composite/metal shear link provided with a continuous fitting element on at least one surface of the casing which receives one end of the aformentioned surface of the casing, provided with attachment pins passing through the fitting and the end of the surface.

Abstract: A method of making a mechanical multishear link includes sizing the multishear link by breaking down a system comprised by the link into as many subassemblies as there are simple shear interfaces, defining the subassemblies around each shear interface, describing each shear by its stiffness, and applying the mechanical relationships to achieve a system of equations for a computer-assisted resolution by applying the Huth method to each shear interface.

Abstract: Method for producing a connecting rod, particularly a monoblock composite connecting rod, and the resulting connecting rod is provided by placing preimpregnated fibers on an extractable mandrel, with the following successive stages. Embodying on a rigid central shaft a meltable mandrel with a shape corresponding to that of the connecting rod; winding and/or laying down the preimpregnated fibers according to a predetermined number of layers and an inclination of the fibers with respect to the longitudinal axis of the mandrel; polymerization with a homogeneous compacting pressure being applied to the entire outer surface of the unit; and then final operations for removing the mandrel and machining to required dimensions of the connecting rod.

Abstract: Process for optimizing the features of multilayered tubes made of fibrous composite materials, allowing to maintain within the specified limits the limit elongations and stresses which they withstand in response to the applied strains. The process comprises selecting at least two optimized features characteristic of each layer (its thickness and the winding angle of the fibers for example) by starting from an initial tube selected a priori. Through small deviations applied to the parameters, the relations between small deviations applied to the parameters and the variations of the resulting limit elongations and stresses are determined, as well as the inverse relations relating the variations of the limit elongations and stresses to the parameter deviations. Knowing these inverse relations allows, in one or several stages, to find out the deviations to be applied in order to make up the measurable differences between the limit elongations and stresses of the optimized tube and the tube selected a priori.

Abstract: A composite material tube, withstanding the internal pressure, and comprising at least two layers of pressure reinforcement fibers, or pressure resistant layers, wound at an angle at least equal in absolute value to 70.degree., with respect to the center axis of the tube. The two layers both undergo radial expansion under an effect of the pressure, with one of these two layers being inside the other. A circumferential modulus of elasticity of the external layer is greater than the circumferential modulus of elasticity of the internal layer.

Abstract: A process for manufacturing a line of variable stiffness over part of the length thereof and the associated element which allows the line to have the variable stiffness thereof is disclosed. The element is integrated during the manufacturing of the line or deposited thereafter around the line; the element consists of composite material underlayers in which the directions of the fibers have at least one component making a zero or a low-value angle with the axis of the pipe, and the layers end in a graded way. The process has application to the manufacturing of a riser base.

Abstract: A method for producing a connecting rod, particularly a monoblock composite connecting rod, by placing preimpregnated fibers on an extractable mandrel, with the following successive stages. Embodying on a rigid central shaft a meltable mandrel with a shape corresponding to that of the connecting rod; winding and/or laying down the preimpregnated fibers according to a predetermined number of layers and an inclination of the fibers with respect to the longitudinal axis of the mandrel; polymerization with a homogeneous compacting pressure being applied to the entire outer surface of the unit; and then final operations for removing the mandrel and machining to required dimensions of the connecting rod.

Abstract: A method for hooping and maintaining in compression a core by a sheath, with the sheath being made of a composite material and having an internal cross section which is less than an external cross section of the core. The core and the sheath are aligned by centering them with respect to each other, and a prior tensile force is exerted over the core to provide a suitable sealing between the portion in contact of each of the ends of the core and of the sheath. A pressurized fluid is injected into the sheath in a direction of the core, to increase the cross section of the sheath by expanding the sheath in a circumferential direction. The core is thereby gradually inserted into the sheath. When the insertion is complete, fluid injection is ceased and an expendable portion of the sheath is cut off.

Abstract: A method of joining a tube of composite material and a tubular metal fitting includes, winding filaments of pre-impregnated fibers to produce a tube with a longitudinal axis. The fibers that provide tensile strength for the tube are at a tensile fiber angle relative to the longitudinal axis. A tubular metal fitting is introduced at least partially into an end of a tube section, with inner and outer parts of the fitting being located inside and outside of the tube section. The inner and outer parts are secured by inserting penetrating elements extending radially through the tube section and the parts of the fitting. The penetrating elements are arranged in uniform circumferential alignments which are equally spaced from each other along the longitudinal axis.

Abstract: A composite material tube, substantially insensitive to the variations of elongation under the effect of the internal pressure, comprising a number n of stable layers of reinforcement fibers, the fibers of each layer (i) being placed at the same winding angle in absolute value, referenced theta, with respect to the axis of the tube with an equal proportion of fibers wound at said angle in one direction (.vertline.theta.vertline.) as fibers wound in the opposite direction (-.vertline.theta.vertline.), the fibers of each layer being buried in a matrix which adheres to these fibers. The fibers of the same layer and the associated matrix have a volume referenced Y, the parallel fibers of the same layer and the associated matrix having overall a modulus of elasticity in the natural direction of the fibers, referenced E, wherein said n layers of fibers comply as a whole with the following relationship:0.35.ltoreq.A.ltoreq.0.

Abstract: Fibers, which are substantially longitudinally profiled, are wound both around a cylindrical mandrel and a metallic double cone-shaped tip which is engaged onto said mandrel. Said fibers are turned back about studs distributed on a ring which is mounted on a threaded portion extending from the tip, whereupon said longitudinal fibers are binded thereto by means of circumferential fibers before the polymerization process of the tube has been completed. The composite tubes thus produced may be used in off-shore oil prospecting.

Abstract: The present invention concerns a receptacle for the storage of fluid under pressure and comprising an internal casing with axis X,X' and having one central cylindrical section and two extremity sections, an armouring encompassing said casing and leaving clear at the convex extremity section a cap centered on axis X,X'.According to the invention, the outer contour (8) of said convex extremity section (2b) of the casing (2) has, as a longitudinal section, a shape which is at least approximately elliptical so that the ratio G of the small half axis to the major axis is such that:0.32.ltoreq.G.ltoreq.0.4 (I)where the major axis corresponds to the outer diameter of the central cylindrical section (2a) of the casing (2), and the thickness e.sub.i of said convex extremity section (2b), said cap (6) being excluded, varies according to the formula: ##EQU1## in which: R.sub.i =distance to the axis X,X' of the point of the outer contour (8) of said convex extremity section (2b) at which the thickness e.sub.

Abstract: There is provided a process for providing a metal connector fixed to a pipe of composite material and a pipe thus made.A pipe carries at one of its extremities a metal connector, and a first film of elastomer being interposed between the two and adhering to each of them an adhesive. At the level of this extremity, the pipe also carries a metal casing which is held solidly on the connector by a band and a second film of an elastomer which is interposed between the casing and the pipe and adheres by means of an adhesive to each of them.The pipes according to the invention are suitable for use in offshore oil exploration.