Abstract: A fiber structure for reinforcing a composite material part, the structure being woven as a single piece by multilayer weaving between a first plurality of layers of yarns extending in a first direction and a second plurality of layers of yarns extending in a second direction. The second plurality of layers of yarns includes at least one layer of variable-weight yarns, each variable-weight yarn including a separable assembly of individual yarns, each having a determined weight. The fiber structure includes at least one portion of reduced thickness in which the variable-weight yarn presents a weight that is less than the weight that it presents prior to the reduced thickness portion.

Abstract: In a fiber structure woven as a single piece by three-dimensional weaving, first weft yarns interlink layers of warp yarns in a first portion of the fiber structure adjacent to a non-interlinked zone and also warp yarns of a second portion of the fiber structure beyond the non-interlinked zone, and second weft yarns interlink layers of warp yarns of the second portion of the fiber structure adjacent to the non-interlinked zone and also layers of warp yarns of the first portion of the fiber structure beyond the non-interlinked zone, such that the paths of the first and second weft yarns cross in at least one transition zone extending within the fiber structure from the end of the non-interlinked zone, the transition zone extending in the weft direction over a distance greater than the pitch between adjacent warp columns.

Abstract: A fiber structure reinforcing a composite material part woven as a single piece by multilayer weaving between plural first and second layers of yarns. The fiber structure includes a portion of decreasing thickness that presents: plural yarn withdrawal parts in surface continuity, with yarns interrupted from the first plural layers of yarns underlying the layer of yarns of the first plural layers of yarns situated in the surface of the structure; and plural yarn withdrawal parts in surface discontinuity, with yarns interrupted from the first plural layers of yams situated at the surface of the structure, each interrupted yarn replaced in the surface of the structure by a yarn of a layer of yarns underlying the first plural layers of yarns. The yarns of the second plural layers of yarns situated in the surface of the fiber structure are continuous over at least the entire portion of decreasing thickness.

Abstract: A three dimensional woven preform, a fiber reinforced composite incorporating the preform, and methods of making thereof are disclosed. The woven preform includes two or more warp steered fabrics. The warp steered fabrics include a darted portion and an un-darted portion. The darted portions of the warp steered fabrics are joined to un-darted portions of one another so as to provide continuous fiber in the circumferential and radial directions of all portions of the preform. An un-darted portion in one steered fabric reinforces a darted portion in the other. The warp steered fabrics can be woven on a loom equipped with a differential take-up mechanism. The warp steered fabrics can be single or multilayer fabrics. The final preform can be a portion of an aircraft window frame.

Abstract: A fiber preform of ?-shaped section, the preform including a base with a first face and an opposite second face, legs extending from the second face, and a fiber structure woven as a single piece by three-dimensional weaving with a plurality of layers of warp or weft yarns linked interlinked by weft or warp yarns in a plurality of layers of weft or warp yarns. In each plane of the preform, the weft or warp yarns of a first group of weft or warp yarns extend continuously through the base between two opposite edges thereof, and weft or warp yarns of a second group of weft or warp yarns extend continuously from an end of one of the legs to an end of the other leg, passing via the base, with the yarns of the first group and the yarns of the second group presenting two mutual crossings.

Abstract: A fiber preform is formed by a fiber structure woven by three-dimensional weaving with a plurality of layers of warp yarns interlinked by weft yarns of a plurality of layers of weft yarns, the fiber preform having a first portion and a second portion that extend one another in the weft direction and that are at an angle to each other. In the fold zone and in each weft plane of the fiber structure, two weft yarns situated in a region adjacent to an outside face of the fiber structure situated on the inside of the corner present paths that cross, so that less curvature is imposed on these yarns.

Abstract: A quasi-isotropic three-dimensional preform and a method of making thereof are disclosed. The preform includes a plurality of woven elements that are braided with each other. The woven elements have one or more integrally woven stiffeners or walls in a direction perpendicular to the plane of the woven element. The preform may be used in forming a fiber reinforced composite.

Abstract: An integrally woven three-dimensional preform with stiffeners in two or more directions constructed from a woven fabric having a first, second and optional third woven fabric layer. A plurality of yarns are interwoven over a region between the first and second fabric layers such that the first fabric layer is foldable relative to the second fabric layer. An additional plurality of yarns are interwoven over a region between the second and third fabric layers such that the third fabric layer is foldable relative to the second fabric layer. Upon folding of the woven fabric layers, the integrally woven three-dimensional preform with stiffeners in two or more directions is formed.

Abstract: Preforms including fiber reinforced nodes for use in fiber reinforced composite structures and methods for making fiber reinforced composite structures. Preforms with woven fabric elements extending radially from a common node include at least one reinforcing fiber interwoven between at least two elements and passing through the node. A method of assembling preform structures using the preforms to provide a structure with reinforced nodes.

Abstract: A three-dimensional corner lap joint preform and a method of forming a three-dimensional corner lap joint preform including a woven flange with one or more legs that extend from the flange. The legs may include one or more independently woven portions which allow formation of a corner without darting the leg or adding additional reinforcement. The independently woven portions may include warp fibers which are not woven into the preform. The unwoven area allows removal of a portion of the leg prior to formation of the corner, allowing the portions of the leg to overlap and form a lap joint.

Abstract: Preforms including fiber reinforced nodes for use in fiber reinforced composite structures and methods for making fiber reinforced composite structures. Preforms with woven fabric elements extending radially from a common node include at least one reinforcing fiber interwoven between at least two elements and passing through the node. A method of assembling preform structures using the preforms to provide a structure with reinforced nodes.

Abstract: Woven preforms, for example those used for jet aircraft engine fancases, may need additional stiffeners to improve the strength and/or dynamic performance of the preform assembly, as well as to serve as attachment points. The present invention describes several improved woven preforms that include circumferential or axial stiffeners, as well as methods of manufacturing the same. One embodiment includes circumferential stiffeners added to a woven preform. Another embodiment includes sub-preforms with integral flanges that combine to make integral stiffeners. A further embodiment includes an intermediate stiffener wrapped onto a base sub-preform wrap, wherein the intermediate stiffener wrap incorporates intermediate stiffeners. Another embodiment incorporates bifurcations in one or more layers of an outermost wrap of a multi-layer fabric composite that forms a preform, wherein the bifurcated outer wrap is folded to form stiffeners that may be oriented circumferentially or axially.

Abstract: The present invention generally relates to an integrally woven three-dimensional preform with at least one sidewall in at least one direction constructed from a woven base fabric comprising two or more layers, and a method of forming thereof. A plurality of fibers in a first direction is interwoven between at least the top layer and a second layer, such that top layer is foldable relative to the other layers and form, upon folding, an integral sidewall. A plurality of fibers may also be interwoven between the second-from-the-top layer and a second layer, such that the second-from-the-top layer is foldable relative to the other layers, upon folding, form a second integral sidewall perpendicular to the first integral sidewall. The preform may optionally comprise a plurality of non-integral sidewalls formed by folding portions of the topmost layer.

Abstract: A corner fitting preform and a method of forming a corner fitting preform including steps integrally weaving a base or parent material with one or more flanges or legs that extend from the base is disclosed. The flat woven preform includes specially engineered areas within the legs or flanges that have continuous warp yarns which are not woven. The unwoven areas provide a hinge which allows the flanges of the preform to fold around a corner. After folding, the excess unwoven warp yarns are pulled back through the woven portion of the legs or flanges to produce a preform with continuous warp yarn reinforcement around the corner.

Abstract: Preforms including fiber reinforced nodes for use in fiber reinforced composite structures and methods for making fiber reinforced composite structures. Preforms with woven fabric elements extending radially from a common node include at least one reinforcing fiber interwoven between at least two elements and passing through the node. A method of assembling preform structures using the preforms to provide a structure with reinforced nodes.

Abstract: A woven preform for a reinforced composite material, which may be woven flat and folded into shape. The preform has off-axis reinforcement with one or more legs and/or base extending in an off axis or bias (non 0/90 degree) orientation with respect to the warp/weft fibers. One or more legs extend from a base, the base and legs each having at least two layers of warp fibers. The legs may be parallel or angled to each other. The outer ends of the base and/or the legs may have tapers formed from terminating layers of warp fibers in a stepped or angled pattern.

Abstract: The present invention relates to multidirectionally reinforced fiber preforms that conform easily to complex curvatures, such as, composite turbine fan cases, jet engine containment rings, aircraft fuselage frames, aircraft window frames, and flanged rings for attaching nacelles to aircraft engines. The present invention provides multidirectionally reinforced shape woven preforms with improved strength for composite structures that are axisymmetric as well as non-axisymmetric in nature. The invention is a preform used to reinforce a composite structure which includes a contour woven fabric portion, bi-axially braided, tri-axially braided or bias fabric portion, and/or a polar woven fabric portion, and a method of making thereof. The preform may optionally include a three-dimensionally woven portion. The combination of different forms of fabrics allows the preform to be produced without cutting and darting of the individual plies.

Abstract: A turbomachine blade or vane of composite material comprising fiber reinforcement densified by a matrix is fabricated by a method comprising: making a one-piece fiber blank by three-dimensional weaving; shaping the fiber blank to obtain a one-piece fiber preform having a first portion forming a blade airfoil and root preform and at least one second portion forming a blade platform preform; and densifying the preform with a matrix to obtain a composite material blade or vane having fiber reinforcement constituted by the preform and densified by the matrix, forming a single part with at least one incorporated platform.

Abstract: A reinforcement for a darted three-dimensional Pi or T-shaped preform, a method of making thereof and a composite structure including the reinforcement is disclosed. The reinforcement is a steered fabric having a width, a length, a first face surface and a second face surface separated by a thickness. The first face surface of the steered fabric is affixed to a darted component of the preform. The steered fabric reinforcement can be a single layer or multilayer fabric, which can be woven using a programmable take up system.

Abstract: A corner fitting preform and a method of forming a corner fitting preform including steps integrally weaving a base or parent material with one or more flanges or legs that extend from the base is disclosed. The flat woven preform includes specially engineered areas within the legs or flanges that have continuous warp yarns which are not woven. The unwoven areas provide a hinge which allows the flanges of the preform to fold around a corner. After folding, the excess unwoven warp yarns are pulled back through the woven portion of the legs or flanges to produce a preform with continuous warp yarn reinforcement around the corner.