A process for fabricating a partially polymerized prepreg material. Fibers are impregnated with thermosetting resin. The resin is partially polymerized to a degree of polymerization between 10% and 60%. The thermosetting composite parts are produced by drape forming of the prepreg material. The material laid-up in the form of tapes and heated at a temperature above the glass transition temperature of the prepreg state. The laid-up material is pressed and cooled to return the laid-up material to a temperature below the glass transition temperature of the prepreg state in question.

A process for fabricating a partially polymerized prepreg material. Fibers are impregnated with thermosetting resin. The resin is partially polymerized to a degree of polymerization between 10% and 60%. The thermosetting composite parts are produced by drape forming of the prepreg material. The material laid-up in the form of tapes and heated at a temperature above the glass transition temperature of the prepreg state. The laid-up material is pressed and cooled to return the laid-up material to a temperature below the glass transition temperature of the prepreg state in question.

A preform includes a stack of a plurality of fiber materials. The fiber materials each include a first fiber layer including a reinforcing fiber and having a sheet shape, in which the reinforcing fiber has a melting point and a tensile strength that are higher than a melting point and a tensile strength of an aliphatic polyamide fiber, and a second fiber layer including the aliphatic polyamide fiber and having a sheet shape, and provided on at least one of surfaces of the first fiber layer. The aliphatic polyamide fiber includes a first polyamide resin and a second polyamide resin having a melting point higher than a melting point of the first polyamide resin by 7 degrees centigrade to 50 degrees centigrade.

A carbon fiber mat has discontinuous carbon fibers dispersed in the form of monofilaments, wherein the orientation direction of the monofilaments of the discontinuous carbon fibers is random, number average fiber length (L.sub.n) is at least 1.5 mm and up to 15 mm, and proportion in number (Pa) of the discontinuous carbon fiber monofilaments having a fiber length in the range of median fiber length (L.sub.c)±20% is at least 40% and up to 99%.

A carbon fiber mat has discontinuous carbon fibers dispersed in the form of monofilaments, wherein the orientation direction of the monofilaments of the discontinuous carbon fibers is random, number average fiber length (L.sub.n) is at least 1.5 mm and up to 15 mm, and proportion in number (Pa) of the discontinuous carbon fiber monofilaments having a fiber length in the range of median fiber length (L.sub.c)±20% is at least 40% and up to 99%.

Disclosed is a method for producing a three-dimensional preform (1) comprising the following steps: (a) depositing at least one strip (2) of fibers (5) on a three-dimensionally shaped substrate (3); (b) sewing the at least one strip (2) of fibers (5) onto the substrate (3) with at least one sewing thread (4) forming a seam (6).

A manufacturing method for a component made from composite material, in particular of a turbomachine, includes the steps of producing a preform with a fibrous reinforcement comprising a first fibrous portion and a second fibrous portion, and injecting a pressurized matrix into an injection chamber of an injection mold, in which the preform is arranged. The method further includes the steps of polymerizing the preform and positioning a flexible pocket that encloses a fluid and that is arranged between the first fibrous portion and the second fibrous portion before the injection step. The fluid is configured to apply an additional pressure to the preform of the fluid during the polymerization step.

A manufacturing method for a component made from composite material, in particular of a turbomachine, includes the steps of producing a preform with a fibrous reinforcement comprising a first fibrous portion and a second fibrous portion, and injecting a pressurized matrix into an injection chamber of an injection mold, in which the preform is arranged. The method further includes the steps of polymerizing the preform and positioning a flexible pocket that encloses a fluid and that is arranged between the first fibrous portion and the second fibrous portion before the injection step. The fluid is configured to apply an additional pressure to the preform of the fluid during the polymerization step.

A fiber structure includes a plurality of weft layers and a plurality of warp layers interlinked with three-dimensional or multilayer weaving, the fiber structure including at least first and second portions that are adjacent in the warp direction, the first portion presenting thickness in a direction perpendicular to the warp and weft directions that is greater than the thickness of the second portion. The weft layers situated in the core of the first portion of the fiber structure include braids. The weft layers extending on either side of the weft layers including the braids and going as far as the skin of the first portion include yarns or strands, the braids presenting a section greater than the section of the yarns or strands.

Methods to increase structural performance, strength, and durability of textile-reinforced composite materials are provided. The textile reinforcement may be knitted, for example, in a flat bed weft knitting machine. The method may include pre-stressing a textile reinforcement preform by applying tension. A polymeric precursor may be introduced to the pre-stressed textile reinforcement preform. The polymeric precursor may then be cured or consolidated, followed by releasing of the applied tension to form the composite article comprising polymer and the pre-stressed textile reinforcement. In other aspects, a composite article is provided that has a pre-stressed textile reinforcement structure and a cured polymer. The textile reinforcement may be a knitted, lightweight, seamless, unitary structure. The knitted reinforcement structure may have distinct first and second knitted regions with different levels of pre-stress, thus providing enhanced control over strength, rigidity, and flexibility of the composite article.