Structure intended to stiffen a component made of thermosetting composite material by being fitted to at least one of its surfaces, including: at least one longitudinal body, with first and second longitudinal edge faces on opposite sides, and first and second lateral faces on opposite sides; at least one base including at least one mounting base, each base having a plate and first and second tongues which delimit, with the plate, a housing for at least one body, the first and second tongues extending from a main face of the plate and being pressed respectively against the first and second lateral faces of the body. Each mounting base has a plate which is secured to the first longitudinal edge face of a body and which is intended to be pressed against the surface of the component to be stiffened. Each body and each base are made of thermosetting composite material.

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 connection assembly for connecting a first element to a second element is provided. The connection assembly has a male element and a female element. The female element has a barrel nut. The barrel nut has a conical inner portion positioned at a first longitudinal region and a cylindrical inner portion positioned at a second longitudinal region. The barrel nut has a first engaging element portion and a first plain portion arranged alternatingly around a circumferential direction of the barrel nut. The male element has a cylindrical bolt-like shape and has a second engaging element portion and a second plain portion arranged alternatingly around a circumferential direction of the male element. The male element further has flattened sides at the second plain portion. The second engaging element portion of the male element is configured to engage with a respective one of the first engaging element portion of the barrel nut.

A method of producing at least part of a structural frame of a vehicle, the method comprising: providing a support structure (300), the support structure (300) comprising: a plurality of elongate members (301); and one or more retaining members (208) configured to retain the elongate members (301); mounting a plurality of first structural components (206) to the support structure (300) by coupling the first structural components (206) to the elongate members (301) such that each first structural component (206) occupies a different respective position along the elongate members (301); and attaching a plurality of second structural components (204) to the first structural components (206), thereby coupling together the first structural components (206) to form the at least part of the structural frame of a vehicle.

Cap wrinkling in a contoured composite hat stringer is reduced by constraining the cap as the hat stringer is being formed from a flat composite charge. The cap is constrained by an inflatable bladder placed in a tool set used to form the composite charge.

In an example, a composite stringer is described. The composite stringer includes a skin flange having a first gage, a top flange having a second gage, and a web having a third gage and extending between the skin flange and the top flange. The skin flange is configured to be coupled to a support structure. The support structure includes at least one of a skin of a vehicle or a base charge. The second gage of the top flange is greater than the first gage of the skin flange and the third gage of the web. The skin flange, the top flange, and the web include a plurality of plies of composite material.

In an example, a composite structure having a variable gage is described. The composite structure includes a first end having a first gage, a second end having a second gage, which is less than the first gage, a plurality of continuous plies, and a plurality of drop-off plies. Each continuous ply extends from the first end to the second end. Each drop-off ply includes a tip having a tapered shape. Each drop-off ply extends from the first end to a respective position of the tip of the drop-off ply between the first end and the second end. The tips of the plurality of drop-off plies are arranged in a monotonically-inward pattern.

In an example, a composite stringer assembly includes a composite stringer, a radius filler, and an overwrap layer. The composite stringer includes: (i) a skin flange configured to be coupled to a support structure, (ii) a web, (iii) a lower corner portion of the composite stringer extending from the skin flange to the web, and (iv) an inner surface of the composite stringer extending along the skin flange, the lower corner portion, and the web. The radius filler includes a first surface coupled to the inner surface at the lower corner portion, a second surface configured to couple to the support structure, and a third surface extending between the first surface and the second surface. The overwrap layer is coupled to the inner surface at the web, the third surface of the radius filler, and the support structure.

A system and a method for securing a portion of a fuselage of an aircraft to a portion of a wing of the aircraft include a longeron having a first end and a second end, a first moveable coupling interface that moveably secures the first end to the portion of the fuselage, and a second moveable coupling interface that moveably secures the second end to the portion of the wing.

Described herein are methods and systems for manufacturing composite stringers using independently movable pallets with independent vacuum controls. Specifically, a stringer forming system comprises a base plate and a plurality of sets of pallets (e.g., two or more sets of pallets), slidably coupled to the base plate and forming an adjustable cavity. Each pallet comprises a primary vacuum zone, fluidly connected to a separate vacuum port. The system allows for independent application of a reduced pressure to the primary vacuum zone of each pallet. For example, a reduced pressure is applied only to pallets that are already covered with a composite layup and to pallets that are being covered. Any pallets that are exposed are kept at an ambient pressure and decoupled from a vacuum source, thereby reducing the vacuum leakage through the overall system. As the composite layup is being formed over new pallets, these new pallets are subjected to the reduced pressure.