A core according to one aspect of the present disclosure is a core that is inserted into a space between a skin and a stringer in a step of integrally molding the skin and the stringer, the skin including fiber-reinforced resin, the stringer having a hat-shaped section that is open toward the skin. The core includes: a first die that extends along a longitudinal direction of the stringer and contacts the skin; and a second die that extends along the longitudinal direction of the stringer and is located at an opposite side of the skin across the first die. The second die includes a material that is softer than the first die. The second die includes a slit perpendicular to the longitudinal direction of the stringer.

Methods and structures are disclosed. An example method includes: rotating a tubular mandrel about a longitudinal axis of the tubular mandrel; depositing a composite material on an inner surface of the tubular mandrel to form a composite tubular member on the inner surface of the tubular mandrel; inserting and expanding an inner expandable mandrel within the composite tubular member to cause the inner expandable mandrel to press the composite tubular member against the inner surface of the tubular mandrel; curing the composite tubular member; removing the inner expandable mandrel; placing a frame within the composite tubular member; and removing the tubular mandrel so as to obtain the composite tubular member with the frame placed therein.

A carrier film set configured to apply a number of stiffener assemblies to a layup mandrel, the carrier film set comprising: a number of alignment features configured to align the carrier film set relative to the layup mandrel; and a number of indexing features configured to index the number of stiffener assemblies onto the carrier film set.

A method for connecting two components. In this method, a first component and a second component, which are each formed from a thermoplastic material, are first provided. The first component has a first peel-off ply on a first surface of the first component. The first peel-off ply is removed from the first component. Once the first peel-off ply has been removed, the first surface of the first component is brought into contact with a second surface of the second component. The first component and the second component are then welded to one another at the first and second surface by ultrasonic welding.

Systems and methods are provided for fabricating a preform for a fuselage section of an aircraft. The method includes advancing a series of arcuate mandrel sections in a process direction through an assembly line, laying up fiber reinforced material onto the arcuate mandrel sections via layup stations, uniting the series of arcuate mandrel sections into a combined mandrel; and splicing the fiber reinforced material laid-up onto the arcuate mandrel sections.

A joining system includes a holding fixture assembly configured to hold a fuselage skin. The stringers are temporarily attached to the fuselage skin. The joining system includes an upper beam assembly including an upper beam and a lower beam assembly. The lower beam assembly includes a lower beam and at least one lower heating element. The holding fixture assembly is coupled to the upper beam assembly. The holding fixture assembly is coupled to the lower beam assembly. The upper beam is movable relative to the lower beam to clamp the at least one of the plurality of stringers and the fuselage skin together prior to and during welding.

A mold assembly for manufacturing a composite part with a stiffener, the mold assembly includes a bottom mold configured to form a first surface of the composite part, wherein the bottom mold has at least one elongated recess configured to form a stiffener in the composite part; a feeder unit having a shape corresponding to the at least one elongated recess, wherein the feeder unit is configured to fit at least partially into the at least one elongated recess; and a top mold configured to form a second surface of the composite part opposite to the first surface. Also a method of manufacturing a composite part using such a mold assembly, which includes draping a flat laminate over the bottom mold and pushing portions of the laminate into the at least one elongated recess.

There is provided a forming apparatus for forming a high contour composite structure. The forming apparatus includes an upper die and a lower die between which a composite charge is formed. The forming apparatus further includes a plurality of load cells, a control system, and an overlay tool assembly coupled to the upper die. The overlay tool assembly has scalloped sections positioned between pairs of the plurality of load cells, and positioned against portion(s) of the composite charge. The composite charge has ply discontinuity features through the one or more portions. The overlay tool assembly denies pressure and a through thickness compaction to the one or more portions of the composite charge during a forming process, to allow one or more plies in the one or more portions to move after the forming process, and to enable in-plane bending of the high contour composite structure in post-forming operations.

A method may comprise: laying up a first plurality of plies of material comprising thermoplastic resin and fiber to form an inner skin preform, the inner skin preform being a continuous sheet including alternating peaks and valleys; laying up a second plurality of plies of material comprising thermoplastic resin and fiber to form an outer skin preform; and joining the inner skin preform to the outer skin preform.

Described herein are methods of forming uncured sealant assemblies and also methods of forming seals between various parts using such assemblies. In some examples, an uncured sealant assembly comprises two protective layers and an uncured sealant layer, disposed in between. The uncured sealant assembly is stored and provided at a cure-inhibiting temperature, selected to minimize the curing rate of the uncured sealant layer. The size and the shape of the uncured sealant layer are specifically selected to ensure the complete coverage of the faying surfaces, filling of all gaps and voids between the faying surfaces, and controlling the shape and size of uncured sealant squeeze out between the faying surfaces. In some examples, the size and shape of the uncured sealant layer maybe be specifically selected to have no uncured sealant squeeze out between parts.