A partially separated fiber bundle includes a separated fiber section and an unseparated fiber section, being configured to give a ratio A.sub.max/A.sub.min of 1.1 or larger and 3 or smaller, when the number of fiber bundles contained in the width direction of the partially separated fiber bundle (fiber separating number: N.sub.n) measured at a freely selected point P.sub.n (where, n represents an integer of 1 to 100, and freely selected points P.sub.n and P.sub.n+1, excluding n=100, being 50 cm or more away from each other), is divided by a full width of W.sub.n of the partially separated fiber bundle, to calculate the fiber separating number per unit width A.sub.n, and assuming its maximum value as A.sub.max and its minimum value as A.sub.min.

A water entanglement system having a first rotatable surface comprises a first water jet which may be configured to water-entangle a preform in situ. The water-entanglement system may comprise a second rotatable surface disposed proximate the first rotatable surface. The second rotatable surface may comprise a second water jet configured to water-entangle the preform in situ. The first rotatable surface may be oriented substantially parallel to the second rotatable surface.

A carbon-carbon composite preform including a plurality of layers including carbon fibers or carbon-precursor fibers, the layers include a first exterior layer defining a first major surface, a second exterior layer defining a second major surface, and at least one interior layer disposed between the first exterior layer and the second exterior layer, the at least one interior layer having a peripheral region that forms a portion of an outer surface of the preform. The preform includes needled fibers, where at least some needled fibers extend through two or more layers. The preform has an exterior region and a core region, where the exterior region includes at least the peripheral region of at least one interior layer. The needled fibers define a first needled fiber number density (NFND) in the exterior region and a second greater NFND in at least a portion of the core region.

A circular needle loom comprises a bed plate for receiving a transport layer. Engagement members may be disposed proximate to the bed plate, such that the engagement members interface with a positional structure of the transport layer that is used to position and rotate the transport layer around the bed plate. The engagement members may be configured to rotate the transport layer around the bed plate until a predetermined number of fibers and/or layers are deposited on the transport layer and/or bed plate in order to create a needled preform.

A circular needle loom comprises a bed plate for receiving a transport layer. Engagement members may be disposed proximate to the bed plate, such that the engagement members interface with a positional structure of the transport layer that is used to position and rotate the transport layer around the bed plate. The engagement members may be configured to rotate the transport layer around the bed plate until a predetermined number of fibers and/or layers are deposited on the transport layer and/or bed plate in order to create a needled preform.

Systems and methods for forming a fibrous preform are disclosed. The method may comprise providing a plurality of needles comprising a barbed needle and a barbless needle and penetrating the fibrous preform with the plurality of needles.

A transport of carbon fiber bundles, in as fabricated carbon fiber tow form, with in-line manipulation of the fiber bundles (spreading or spreading and volumization with manipulators) during fiber bundle transport is described herein. A method including positively transporting and placing a fiber bundle via a moveable fiber bundle delivery mechanism interposed between a fiber bundle supply and a fiber bundle delivery location, manipulating at least one of a fiber volume and an areal weight of the fiber bundle via an air jet device coupled between the fiber bundle delivery location and the fiber bundle supply, and controlling delivery of the fiber bundle tension from the fiber supply through an electronic unwinder is also described.

A transport of carbon fiber bundles, in as fabricated carbon fiber tow form, with in-line manipulation of the fiber bundles (spreading or spreading and volumization with manipulators) during fiber bundle transport is described herein. A method including positively transporting and placing a fiber bundle via a moveable fiber bundle delivery mechanism interposed between a fiber bundle supply and a fiber bundle delivery location, manipulating at least one of a fiber volume and an areal weight of the fiber bundle via an air jet device coupled between the fiber bundle delivery location and the fiber bundle supply, and controlling delivery of the fiber bundle tension from the fiber supply through an electronic unwinder is also described.

A resin-integrated carbon fiber sheet 1, including: a carbon fiber sheet 2 in which a carbon fiber filament group is spread and arrayed in parallel in one direction; resin 4 that is present on part of a surface of the carbon fiber sheet; and bridging fibers 3. One or more of the bridging fibers 3 is present on average on a surface of the carbon fiber sheet 2 in a direction across the carbon fiber sheet per 10 mm.sup.2 of the sheet 2, and the resin 4 on the surface adhesively fixes the bridging fibers 3 to the carbon fiber sheet 2. Thus, the present invention provides a resin-integrated carbon fiber sheet that is strong in the width direction of the carbon fiber sheet, high in cleavage resistance and excellent in handleability, and a production method of the same.

A resin-integrated carbon fiber sheet 1, including: a carbon fiber sheet 2 in which a carbon fiber filament group is spread and arrayed in parallel in one direction; resin 4 that is present on part of a surface of the carbon fiber sheet; and bridging fibers 3. One or more of the bridging fibers 3 is present on average on a surface of the carbon fiber sheet 2 in a direction across the carbon fiber sheet per 10 mm.sup.2 of the sheet 2, and the resin 4 on the surface adhesively fixes the bridging fibers 3 to the carbon fiber sheet 2. Thus, the present invention provides a resin-integrated carbon fiber sheet that is strong in the width direction of the carbon fiber sheet, high in cleavage resistance and excellent in handleability, and a production method of the same.