Abstract: A composite charge is formed between two compression dies into a composite laminate stiffener. The stiffener is contoured along its length by contouring the dies. Wrinkle diffusers attached to, or embedded or incorporated into the tool surfaces of the dies, diffuse wrinkles formed on the inside radius of the stiffener during the contouring.

Abstract: A tool for making contoured composite hat stringers allows control of stringer wrinkling. The tool includes a set of first openings that allow the tool to flex during contouring of the stringer, and a set of second openings into which portions of the composite charge may strain during the contouring.

Abstract: Composite laminate stiffeners such as stringers are punch formed between first and second universal dies respectively carried on first and second trays. The second tray is mounted for sliding movement relative to the first tray between a punch position and a compaction position. Parts of the first and second dies are easily reconfigurable, allowing different shapes of stiffeners to be formed on the same forming apparatus.

Abstract: 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.

Abstract: Systems are provided for fabricating a preform for a fuselage section of an aircraft. The system 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.

Abstract: A composite charge is formed between two compression dies into a composite laminate stiffener. The stiffener is contoured along its length by contouring the dies. Wrinkle diffusers attached to, or embedded or incorporated into the tool surfaces of the dies, diffuse wrinkles formed on the inside radius of the stiffener during the contouring.

Abstract: 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.

Abstract: A composite laminate stiffener is formed to contour with reduced ply wrinkling using constrained creep forming. The tooling apparatus is provided with flexible cauls which constrain the stiffener during the contour forming process. The creep forming is carried out at a slow enough rate so that friction or shear resistance between the resin and fibers of the plies remains low enough that slippage can occur and significant compression stresses are not generated rate, allowing relaxation of residual stresses in the stiffener.

Abstract: A flexible caul for applying pressure to a part comprises a caul member having a plurality of spaced apart gaps therein to provide the caul member with flexibility, and a flexible covering that limits flexing of the caul member.

Abstract: A drape forming apparatus includes a forming tool having a first forming surface and a second forming surface nonplanar with the first forming surface. A tray is spaced apart from the forming tool and is configured to pivot about a hinged end from a first position to a second position under an applied force such that a distal end moves away from the forming tool. A first side of the tray faces a first heat source when the tray is in the first position, and a second heat source is disposed at a second side of the tray. A device for use in forming the composite structure includes a standoff and the tray, and a heat source is secured to the second side of the tray. A method of forming a composite structure includes heating both sides of the composite material with the first and second heat sources.

Abstract: 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.

Abstract: Systems and methods are provided for fabricating multiple segment spars for an aircraft. In one example the method includes fabricating preforms of fiber reinforced material for spar segments, hardening the preforms to form the spar segments, and bonding the spar segments together to form a completed spar detail. In addition to bonding, other examples include co-curing and fastening the spar segments. In additional examples, the spar segments include kinks or sub-kinks as described.

Abstract: A tool is configured to form a composite charge into a stringer having a net shape with at least one out-of-place feature. The out-of-plane feature is formed by a shim removably attached to the tool. A family of the shims may be used to form a range of out-of-plane features having varying characteristics.

Abstract: A tool for making contoured composite hat stringers allows control of stringer wrinkling. The tool includes a set of first openings that allow the tool to flex during contouring of the stringer, and a set of second openings into which portions of the composite charge may strain during the contouring.

Abstract: 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.

Abstract: A composite laminate stiffener is formed to contour with reduced ply wrinkling using constrained creep forming. The tooling apparatus is provided with flexible cauls which constrain the stiffener during the contour forming process. The creep forming is carried out at a slow enough rate so that friction or shear resistance between the resin and fibers of the plies remains low enough that slippage can occur and significant compression stresses are not generated rate, allowing relaxation of residual stresses in the stiffener.

Abstract: A flexible caul for applying pressure to a part comprises a caul member having a plurality of spaced apart gaps therein to provide the caul member with flexibility, and a flexible covering that limits flexing of the caul member.

Abstract: An end effector transports, places and forms a composite ply on a tool having complex tool surfaces. The end effector includes a combination of vacuum and Bernoulli grippers for holding the composite ply while it is being transported and formed, and a set of mechanical actuators that form the composite ply down over the tool surfaces. The Bernoulli grippers allow the composite ply to slip while being held and formed.

Abstract: Methods of assembling stiffened composite structures are disclosed. Some methods include forming a stiffener assembly by compacting it within a trough formed in a trunnion. A single trunnion may accommodate two or more different types of stiffeners, thereby avoiding the need for multiple sets of tooling. In some methods, a plurality of stiffener segments may be spliced together, thereby avoiding the need to transport and handle an entire stiffener. A vacuum chuck may be utilized in some examples to transfer the stiffener assembly from the trunnion to a transfer tool. The same vacuum chuck may be transferred along with the stiffener assembly on the transfer tool and loaded onto an inner mold line layup mandrel, where the vacuum chuck may be used to compact the stiffener assembly to the inner mold line layup mandrel.

Abstract: A drape forming apparatus for use in forming a composite structure. The apparatus includes a forming tool including an upper forming surface and at least one side forming surface that extends from the upper forming surface. The forming tool receives at least one layer of composite material over the upper forming surface. The apparatus also includes a flange forming device including a tray coplanarly aligned with the upper forming surface when in a first operating position. The tray is configured to receive a flange portion of the at least one layer of composite material. A pressurized bladder extends over the forming tool and the tray. The pressurized bladder is configured to induce a first force against the tray such that the tray rotates about a pivot line, and such that the flange portion is withdrawn from the tray and draped over the at least one side forming surface.