Patent Description:
Composite laminate stiffeners such as stringers are often produced by assembling and co-curing multiple composite components. In some stiffener applications, such as the stringers used in the wings and fuselage of an aircraft, the stringers are required to be contoured along their length. Because of the changing geometries of a wing or fuselage, many of the stringers are uniquely contoured and thus must be formed using different sets of forming tools. Moreover, the tool sets used to cure the stringers are often different from the tool sets used to form the stringers to the desire contours. The need for multiple sets of differently configured tools adds to capital expense and floor space requirements, and may limit production rate.

Accordingly, there is a need for a method and apparatus for producing contoured composite stiffeners such as stringers, which reduce tooling costs as well as floor space requirements, while increasing production rate.

<CIT>, in accordance with its abstract, states a method is provided of fabricating a composite stiffener having a curved web and at least one curved flange. A substantially straight length of unidirectional prepreg tape is placed on a carrier. The at least one curved flange is formed by using the carrier to steer a first portion of the tape onto a first curved tool surface. The curved web is formed by using the carrier to form a second portion of the tape onto a second curved tool surface.

<CIT>, in accordance with its abstract, states that, in a process for laying up a composite product from material sections of different shapes, a continuous band of the material is taken from a feed roll on a carrier film and the individual sections are cut out without cutting through the carrier film. The cutting order is the reverse of the lay-up sequence and the film and band are wound up on a storage roll. The band is then unwound at a take-off station and each section is stripped from the carrier film and placed in the mould using optical methods for accuracy. Also described is the apparatus used comprising a cutting machine with table for cutting sections, material feed and take-up rolls and a material placing station with optical apparatus for accurate location of sections in a mould, a section stripping station between the other stations which removes individually cut sections from the carrier and has a table with a section removing edge at one end, rolls in front of and behind the table which feed the carrier film and strip material and take off the scrap, and a computer which controls shape, location and arrangement of cut sections and is connected to the cutting machine, the section stripping station and the optical placing equipment.

<CIT>, in accordance with its abstract, states that a method of forming a flat composite charge into a contoured composite part reduces wrinkles in the part as the charge is being formed. Dies are used to form a portion of charge to the steepest contour of the part, while tension is maintained on the charge as the remaining portions of the charge are formed.

There is described herein a method of fabricating a contoured composite stiffener comprising multiple assembled components, the method comprising: assembling a composite charge, including laying up at least one composite ply, for each component of the multiple assembled components; rolling the composite charges onto a roll; transporting the roll having the composite charges thereon to a forming station including a reconfigurable forming mandrel; for each of the composite charges: configuring a shape of the reconfigurable forming mandrel to substantially match a contour of the composite stiffener; configuring a reconfigurable former to substantially match the contour of the composite stiffener; placing the composite charge on the reconfigurable forming mandrel, including unrolling the composite charge from the roll at the forming station; forming the composite charge on the reconfigurable forming mandrel, wherein forming the composite charge on the reconfigurable forming mandrel is performed using the reconfigurable former, and configuring the shape of the reconfigurable forming mandrel includes- adjusting a reconfigurable mandrel support to generally match the contour of the composite stiffener, loading the reconfigurable forming mandrel onto the reconfigurable mandrel support, and configuring the shape of the reconfigurable forming mandrel to substantially match the contour of the reconfigurable mandrel support; and transporting the reconfigurable forming mandrel having the formed composite charge thereon to an assembly station; and assembling the formed composite charges, corresponding to the multiple assembled components, at the assembly station to form the composite stiffener.

There is also described herein an apparatus for fabricating a composite stiffener comprising multiple assembled components, comprising: a composite ply layup table; a spool adapted to hold a length of a flexible film on which composite plies may be laid up for each component of the multiple assembled components, the spool being positioned to allow the flexible film to be drawn from the spool onto the layup table; a transportable roll located adjacent the layup table on which the flexible film and composite plies for each component of the multiple assembled components thereon may be rolled up; a reconfigurable forming mandrel on which the composite plies may be formed, a shape of the reconfigurable forming mandrel being configurable to substantially match a contour of the composite stiffener; a reconfigurable mandrel support, wherein the reconfigurable forming mandrel is removably mounted on the reconfigurable mandrel support, the reconfigurable mandrel support being adjustable to generally match the contour of the composite stiffener; and a reconfigurable former for forming the composite plies over the reconfigurable forming mandrel, the reconfigurable former being configurable to substantially match the contour of the composite stiffener; and an assembly and bagging station.

The disclosed embodiments provide a method and apparatus for fabricating elongate stiffeners such as stringers, particularly those that are contoured along their length. The method permits forming the stringers in contour rather than forming them straight and then bending them to the desired contour. The apparatus is readily reconfigurable to form stiffeners having various contours, thus reducing tooling costs. The stiffeners may be formed hot or cold, either single ply, multiple plies or entire stacks, in a single forming operation. By forming the stiffeners in contour, ply wrinkling is substantially reduced or eliminated. Components of the stiffener are produced by forming composite charges to the desired contours using mechanical pressure without the need for vacuum pressure.

The features, functions, and advantages can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings.

The illustrative embodiments, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment of the present disclosure when read in conjunction with the accompanying drawings, wherein:.

The disclosed embodiments relate to a method and apparatus for producing composite laminate stiffeners, particularly those that are contoured along their length. For example, referring to <FIG>, a composite laminate stiffener in the form of a blade-type stringer <NUM> comprises a flat base <NUM> having a contour <NUM> along its length that is adapted to match an outer skin (not shown) of a wing or fuselage, and a central blade <NUM>, also contoured along its length. The stringer <NUM> may comprise multiple assembled components (<FIG>), such as a pair of right angle components <NUM> arranged back-to-back and a cap <NUM>. Each of the right angle components <NUM> comprises a pair of legs 50a, 50b intersecting along an outside radius edge 50c. In the illustrated example, an additional component comprising a composite filler <NUM>, sometimes referred to as a "noodle", fills a void between the cap <NUM> and the outside radius edges 50c of the right angle components <NUM>. It is to be understood that the stringer <NUM> shown in <FIG> is merely illustrative of a wide range of contoured composite laminate stiffeners and structural members that may be produced according to the disclosed method and related apparatus.

Attention is now directed to <FIG> which diagrammatically illustrates a method of laying up and assembling components of a composite laminate structure, such as the components <NUM>, <NUM> shown in <FIG> that are assembled to form the composite laminate stringer <NUM> shown in <FIG>. Each of the components <NUM>, <NUM> is produced by laying up and forming a corresponding, multiply composite charge <NUM>. Each of the composite laminate charges <NUM>, comprising one or more composite plies such as a prepreg, is assembled at a layup station <NUM> by laying up the plies on a section of a continuous length of flexible film <NUM> supported on a substrate such as table. The layup process may be performed by an automated material placement machine (not shown in <FIG>) that lays up each charge <NUM>, ply-by-ply on the film <NUM>. The charges <NUM>, along with the film <NUM> are spooled onto a transportable roll <NUM> at the layup station <NUM>. The roll <NUM>, having one or more charges <NUM> spooled thereon, is then transported by any suitable means, to a forming station <NUM>. In one embodiment, the roll <NUM> may contain all of the charges <NUM> necessary to produce the components of a single stringer <NUM>, while in other embodiments the roll <NUM> may contain all of the charges needed to produce a plurality of the stringers <NUM>.

The forming station <NUM> includes a reconfigurable former <NUM> and a reconfigurable forming mandrel <NUM>. The roll <NUM> is positioned at one end of the forming mandrel <NUM>, where a section of the film <NUM> having a charge <NUM> therein may be unspooled (unrolled) from the roll <NUM> and drawn across the length of the forming mandrel <NUM>. Each charge <NUM> is then transferred onto the forming mandrel <NUM>. The charge <NUM> is swept down onto the forming mandrel <NUM> in order to form the charge <NUM> to the desired cross-sectional shape and longitudinal contour. After a charge <NUM> has been transferred from the film <NUM> to the mandrel <NUM>, the film <NUM> is drawn onto a take-up roll <NUM>, thereby unrolling the next-to-be-formed charge <NUM>. After each charge <NUM> is formed into a component <NUM> of the stringer <NUM>, the formed component <NUM> along with the forming mandrel <NUM> are transferred, using any suitable technique such as an overhead crane (not shown), to an assembly and bagging station <NUM> where the components <NUM>, <NUM> are assembled and vacuum bagged, in preparation for curing. In one embodiment, the base component <NUM> is unrolled at the time of assembly of the components <NUM>, <NUM> and placed over the two assembled components <NUM>. In other embodiments, component <NUM> may be formed to the desired contour over a forming mandrel <NUM> at the forming station <NUM>, and then transferred on the mandrel <NUM> to the assembly and bagging station <NUM> for assembly along with the formed components <NUM>. From the foregoing, it may be appreciated that any number of pre-kitted composite laminate charges <NUM> may be efficiently laid up and transported as a group on one or more rolls <NUM> to one or more forming stations <NUM>. Thus, a single layup station <NUM> may be employed to produce an inventory of composite charges <NUM> ready for forming at one or more forming stations, on an as-needed basis.

<FIG> and <FIG> illustrate additional details of one embodiment of the layup station <NUM>. The layup station <NUM> broadly comprises an automated material placement (AMP) machine <NUM> which automatically lays up plies of a composite charge <NUM> on an elongate layup table <NUM>. The layup table <NUM> may include surface perforations therein and a vacuum system (both not shown) which draw down the film <NUM> onto the surface of the table <NUM> and hold the film <NUM> during the ply layup process. The roll <NUM> is mounted on a transportable frame <NUM> which may be moved into position to support the roll <NUM> at one end of the table <NUM>. Pinch rollers <NUM> may be provided to smooth any wrinkling in the film <NUM> before it is spooled onto the roll <NUM>. A supply spool <NUM> of the film <NUM> is positioned at the other end of the table <NUM>.

The AMP machine <NUM> may comprise, for example and without limitation, an automated fiber placement (AFP) machine for laying up composite tows, or automated tape placement (ATP) machine for laying up composite tape. The AMP machine <NUM> includes a composite material placement head <NUM> mounted on a gantry arm <NUM> that is the movable along rails <NUM> forming a gantry type manipulator. Other types of manipulators may be employed, such as an articulated arm robot (not shown), to move the material placement head <NUM> over the layup table <NUM> along X, Y and Z axes <NUM>.

In use, film <NUM> is unrolled from the supply spool <NUM>, drawn over the length of the table <NUM> and threaded through the pinch rollers <NUM> and onto the roll <NUM>. With the film <NUM> held in a fixed position on the table <NUM> by vacuum suction, the AMP machine <NUM> lays up the plies of the charge <NUM>, in registration with each other, while the film <NUM> is held stationary on the table <NUM>. When layup of a charge <NUM> is completed, the film <NUM> is spooled onto the roll <NUM>, thereby drawing a fresh length of film <NUM> from the supply spool <NUM> onto the table <NUM>. In some embodiments however, it may be possible to begin schooling the film <NUM> onto the roll <NUM> has the charge <NUM> is being laid up thereon. Although not shown in the Figures, the roll <NUM> and/or the supply spool <NUM> may be automatically power operated by suitable motors and a control system (not shown), while in other embodiments, the process of spooling the film <NUM> on the roll <NUM> may be carried out manually. The process of laying up the charges <NUM> and spooling them onto the roll <NUM> is continued until all of the charges <NUM> needed to produce one or more of the components <NUM>, <NUM> has been completed.

Attention is now directed to <FIG> and <FIG> which illustrate additional details of the forming station <NUM> which comprises a former <NUM> and a flexible and reconfigurable mandrel support <NUM> that is movable. The movable mandrel support <NUM> supports the forming mandrel <NUM> while the former <NUM> sweeps a composite laminate charge <NUM> down over first and second surfaces 68a, 68b (see <FIG>) of the mandrel <NUM>. The forming mandrel <NUM> is flexible along its length. In one embodiment, the forming mandrel <NUM> may be formed of metal or a similar rigid material having a plurality of spaced apart slots or kerfs (not shown) along its length that permit the forming mandrel <NUM> to be bent to a desired contour. In other embodiments, the forming mandrel <NUM> may be formed of a material that is inherently bendable yet possess since sufficient rigidity to function as a forming tool over which a composite materials may be formed.

The mandrel support <NUM> comprises a base <NUM> on which a locating receiver <NUM> is mounted. The mandrel support <NUM> may be formed of any suitable materials capable of supporting the mandrel <NUM> in a fixed position, yet reconfigurable to any desired contour corresponding to the contour of a composite laminate component to be formed. In one embodiment, the mandrel support <NUM> may be slotted along its length to permit it to be bent to a desired contour. When a forming mandrel <NUM> is loaded onto the mandrel support <NUM>, the base <NUM> supports the weight of the mandrel <NUM>, while the locating receiver <NUM> locates the forming mandrel <NUM> in a desired position on the base <NUM> relative to the former <NUM>. The mandrel support <NUM> is mounted on a vertically adjustable supports <NUM>, such as jack screws, that are adjustable, thereby allowing the contour of the mandrel support <NUM> to be vertically adjusted along its length. The adjustable supports <NUM> may be supported on a factory floor <NUM>, or similar underlying supporting surface.

Referring to <FIG>, in one embodiment, the former <NUM> comprises a forming head <NUM> supported beneath a gantry <NUM> by pneumatic cylinders <NUM> which are capable of vertically displacing the head <NUM>. The gantry <NUM> suspends of the head <NUM> above the mandrel support <NUM>. A pair of laterally spaced, block-like forming members <NUM>, <NUM> comprising, for example and without limitation, nylon, are mounted on the head <NUM>. In one embodiment, one of the forming numbers <NUM> may be offset slightly higher than the other forming member <NUM>, for purposes that will become apparent. In some embodiments, depending upon the configuration of the mandrel <NUM>, each of the forming members <NUM>, <NUM> may be articulated to allow the forming member <NUM>, <NUM> to adjust and conform to the surface geometry of the mandrel <NUM>.

A charge support <NUM> secured to and extending the downwardly from the head <NUM> supports a composite charge <NUM> until ready for placement on the forming mandrel <NUM>. Optionally, a heater <NUM>, such as, without limitation an electric coil is secured to the bottom of the charge support <NUM> in order to heat and thereby soften the charge <NUM> in preparation for forming. As will be discussed below, the forming members <NUM>, <NUM>, driven by the pneumatic cylinders <NUM>, sweep a composite charge <NUM> down onto and over the mandrel surfaces 68a, 68b (<FIG>), thereby forming one of the components <NUM>, <NUM> of the stringer <NUM>. The former <NUM> is reconfigurable along its length to substantially match the contour of the stringer components being formed. For example, the gantry <NUM>, the head <NUM> and forming members <NUM>, <NUM> may be either segmented or may consist of individual components along the length of the forming station <NUM> to allow the former <NUM> to substantially match the contour of the forming mandrel <NUM>.

Attention is now directed to <FIG> which diagrammatically illustrate the sequence of operations used to form a composite charge <NUM> to the desired shape and contour. Beginning with <FIG>, the mandrel support <NUM> is adjusted to the desired contour along its length, following which a forming mandrel <NUM> is placed on the mandrel support <NUM> and is adjusted to match the contour of the mandrel support <NUM>. The receiver <NUM> on the base <NUM> serves as a stop to locate the mandrel <NUM> on the base <NUM>. Then, as shown in <FIG>, the forming mandrel <NUM> is locked in its contoured position on the mandrel support <NUM> using any suitable mechanism, such as clamps (not shown).

Next, as shown in <FIG>, the mandrel support <NUM> is moved into position beneath the gantry <NUM>, such that first and second mandrel surfaces 68a, 68b are respectively aligned beneath the forming members <NUM>, <NUM>. The composite charge <NUM> along with the underlying film <NUM> is drawn off of the roll <NUM> and transferred onto the charge support <NUM>, such that a lateral portion 60a of the charge <NUM> overhangs an edge of the charge support <NUM>. Optionally, the composite charge <NUM> may be heated on the charge support <NUM> using the heater <NUM> to soften the charge <NUM> to facilitate forming. Referring to <FIG>, the charge support <NUM> is then lowered, and the charge <NUM> is aligned with the forming mandrel <NUM>. Next, as shown in <FIG>, the contour of the former <NUM> is adjusted to match that of the forming mandrel <NUM>, and the charge <NUM> is adjusted, if needed, so that it is aligned with both the former <NUM>, and the underlying the forming mandrel <NUM>.

Attention is now directed to <FIG> which sequentially illustrate forming of the composite charge <NUM> on the forming mandrel <NUM> at the forming station <NUM>. As shown in <FIG>, the charge <NUM> is adjusted as needed to locate it on the forming mandrel <NUM>, and may be heated in this position, if desired. The head <NUM> (<FIG>) is lowered by the pneumatic cylinders <NUM>, bringing forming member <NUM> into contact with the composite charge <NUM>. Force applied by the pneumatic cylinders <NUM> cause the forming member <NUM> clamp the overhanging portion 60a of the charge against the first surface 68a the mandrel <NUM>, thereby fixing and maintaining the alignment of the composite charge <NUM> on the forming member <NUM> throughout the remainder of the forming process. Referring to <FIG>, with a portion 60a of the charge <NUM> clamped against the first surface 68a of the mandrel <NUM>, continued downward movement of forming member <NUM> brings it into contact with the remainder of the charge <NUM>. As shown in <FIG>, the forming member <NUM> sweeps the charge <NUM> down over a radius edge <NUM> between the two mandrel surfaces 68a, 68b, forming the charge <NUM> down onto mandrel surface 68b of the mandrel <NUM>. <FIG> shows the charge <NUM> having been fully formed by the forming member <NUM>, <NUM> against mandrel surfaces 68a, 68b.

Referring now to <FIG>, with the charge <NUM> having been fully formed, the head <NUM> moves upwardly, disengaging the forming member <NUM>, <NUM> from the fully formed charge <NUM>. Then, as shown in <FIG>, the mandrel support <NUM> is moved away from the former <NUM>, thereby providing the clearance needed to allow the mandrel <NUM> to be removed from the mandrel support <NUM>. Next, shown in <FIG>, a crane pickup <NUM> is attached to the mandrel <NUM>, allowing the crane to unload the mandrel <NUM> and transfer it to the assembly/bagging station <NUM> (<FIG>).

In the embodiment shown in <FIG>, the forming mandrel <NUM> is held in an orientation that causes the composite charge <NUM> to be formed down over the second mandrel surface 68b after having been formed and clamped against the first mandrel surface 68a. However, the sequence in which the individual portions of the charge <NUM> may be altered, if desired, by supporting the forming mandrel <NUM> in a different angular orientation. For example, referring to <FIG>, the forming mandrel <NUM> may be held within a notch <NUM> in the receiver <NUM>, such that the mandrel surfaces 68a, 68b are respectively oriented at differing angles φ<NUM>, φ<NUM> relative to the plane <NUM> of the composite charge <NUM> before forming is commenced. Consequently, during the forming sequence, forming member <NUM> begins sweeping a portion of the charge <NUM> over the angularly oriented mandrel surface 68a, following which forming member <NUM> begins sweeping the remainder of the charge <NUM> over the angularly oriented mandrel surface 68b.

The forming sequence described immediately above is illustrated in more detail in <FIG>. In <FIG>, downward movement of forming members <NUM>, <NUM> initially forces the charge <NUM> into contact with the radius edge <NUM>, at which point forming member <NUM> begins sweeping the charge <NUM> down onto the mandrel surface 68a, until the forming member <NUM> clamps the charge <NUM> against the mandrel <NUM> as best seen in <FIG> also shows the forming member <NUM> beginning to sweep the charge <NUM> down onto mandrel surface 68b, until the charge <NUM> is fully formed against mandrel surface 68b as shown in <FIG>.

<FIG> illustrates an alternate embodiment in which the mandrel <NUM> has another angular orientation that results in the charge <NUM> being simultaneously swept over the two mandrel surfaces 68a, 68b at substantially the same rate. In this embodiment, the two mandrel surfaces 68a, 68b have angular orientations relative to the plane <NUM> of the charge <NUM> that are substantially equal but opposite to each other. In the embodiment of <FIG>, the forming members <NUM>, <NUM> initially force the charge <NUM> into contact with the radius edge <NUM> of the mandrel <NUM>, following which the two forming members <NUM>, <NUM> sweep the charge <NUM> down onto and over the mandrel surfaces 68a, 68b.

<FIG> illustrates the crane pickup <NUM> transferring one of the mandrels <NUM> having a fully formed right angle component <NUM> thereon to the assembly/bagging station <NUM> where another mandrel <NUM> with a component <NUM> thereon has been placed on the table <NUM> covered with a bagging film <NUM>. At this point, the film <NUM> remains on the component <NUM>. Then, as shown in <FIG>, the film <NUM> is removed. Next, as shown in <FIG>, adhesive (not shown) is applied to the radius edges 50c (<FIG>) of each of the right angle components <NUM>, following which the two mandrels <NUM> are clamped together, thereby bringing the two right angle components <NUM> into face-to-face contact with each other. Referring to <FIG>, a radius filler <NUM>, formed of adhesive or composite material, is placed in the void between the radius edges 50c (<FIG>). The cap component <NUM>, which may or may not be pre-formed to the desired contour, is positioned in place and optionally, a caul plate (not shown) is placed over the cap <NUM> in preparation for bagging. Then, as shown in <FIG>, the stringer <NUM> is bagged by drawing the bagging film <NUM> around the assembly of the two mandrels <NUM> and assembled components <NUM>, <NUM>, <NUM>. The assembled stringer <NUM> is then cured using autoclave or out-of-autoclave processing, in which the stringer <NUM> is subjected to a combination of heat and pressure which compacts and cures the stringer <NUM>.

Attention is now directed to <FIG> which illustrates a stringer forming station <NUM> employing certain principles of the embodiments discussed above. The roll <NUM> containing the rolled-up charges <NUM> is transported from the layup station <NUM> (<FIG>) to a first position <NUM> at the forming station <NUM> where it is located at one end of a transportable forming table <NUM>. For example, although not shown in the Figures, the forming table <NUM> may have wheels that allow it to be moved from place-to-place within the forming station <NUM>. The film <NUM> along with a charge <NUM> is pulled from the roll <NUM> and drawn out onto the forming table <NUM>. The film <NUM> is then cut from the roll <NUM> and trimmed as necessary. Optionally, the forming table <NUM> may be transported to a standby position <NUM> adjacent a former <NUM>, where the charge <NUM> may be heated in preparation for forming, using for example, a portable infrared heater (not shown) or heating coils (not shown) integrated into the forming table <NUM>.

Next, the forming table <NUM> is moved to another position <NUM> at the forming station <NUM>, aligned beneath a former <NUM>, which is discussed below in more detail. The charge <NUM> is formed into one of the components <NUM>, <NUM> following which, the forming table <NUM> is moved to a fourth position <NUM> at the forming station <NUM> where the formed component <NUM>, <NUM> may be unloaded and transferred to the assembly/bagging station <NUM> <FIG>). After the components <NUM>, <NUM> are removed from the forming table <NUM>, the forming table <NUM> is moved back to its starting position <NUM>, ready to receive the next charge <NUM> drawn from the roll <NUM>.

<FIG> illustrate an embodiment of a former <NUM> that may be used in the forming station <NUM> shown in <FIG>. The former <NUM> is positioned above the forming table <NUM> which has an overlying, flexible forming membrane <NUM> thereon. The forming membrane <NUM> may comprise, without limitation, silicone rubber. The former <NUM> includes an adapter <NUM> for mounting the former <NUM> on a press (not shown) or other manipulator. The former <NUM> also includes a frame <NUM> having surrounding sidewalls <NUM> forming an enclosure <NUM>, and a pair of longitudinally extending, laterally spaced block-like forming mandrels <NUM> inside the frame <NUM>. The sidewalls <NUM> include seals <NUM> that are adapted to be drawn against of the forming membrane <NUM> to form a vacuum tight enclosure <NUM>. Although not shown in the Figures, the former <NUM> is adapted to be coupled with a vacuum source for drawing a vacuum within the enclosure <NUM>.

<FIG> shows former <NUM> lowered into proximity to the table <NUM> on which a pair of charges <NUM> have been placed in spaced apart relationship to each other. <FIG> shows the former <NUM> having been pressed down onto the table <NUM>, causing the seals <NUM> to form a vacuum tight enclosure <NUM> around the charges <NUM>, while the forming mandrels <NUM> clamp a portion of the charges <NUM> on the table <NUM>. Next, as shown in <FIG>, a vacuum is drawn within the enclosure <NUM>, causing the membrane <NUM> to sweep the charges <NUM> upwardly against the sides of the forming mandrels <NUM>. <FIG> shows the forming membrane <NUM> having fully formed the charges <NUM> into right angle shaped components <NUM>. Referring to <FIG>, with the charges <NUM> fully formed into components <NUM>, the vacuum is released, allowing the forming membrane <NUM> to return to its flat position on the table <NUM>. The former <NUM> may then be raised, allowing the table <NUM> with the formed components <NUM> thereon to be moved away and replaced with another table <NUM> having flat charges <NUM> thereon ready for forming.

Attention is now directed to <FIG> which broadly illustrates the steps of forming a composite stiffener <NUM>. Beginning at <NUM>, a composite charge <NUM> is assembled, for example by laying up at least one composite ply. At <NUM> the composite charge <NUM> is spooled onto a roll <NUM>. At <NUM> the roll <NUM> is transported to a forming station <NUM>. At <NUM>, a forming mandrel <NUM> at the forming station <NUM> is configured to match the desired contour of the stiffener <NUM>. At <NUM>, the composite charge <NUM> is unrolled and placed on the forming mandrel <NUM>. Then, at <NUM>, the composite charge <NUM> is formed on the forming mandrel <NUM>.

<FIG> broadly illustrates the steps of a method of fabricating a contoured composite blade stringer <NUM>. At <NUM>, a plurality of composite charges <NUM> are laid up at a layup station <NUM>. At <NUM>, each of the composite charges <NUM> is rolled up. At <NUM>, the rolled up composite charges <NUM> are transported from the layup station <NUM> to a forming station <NUM>. At <NUM>, the composite charges <NUM> are unrolled at the forming station <NUM>. At <NUM>, each of the composite charges <NUM> is formed into a contoured composite stringer <NUM> component <NUM>, <NUM>. At <NUM>, the stringer components <NUM>, <NUM> are transported from the forming station <NUM> to a stringer assembly station <NUM>. At <NUM>, the stringer components <NUM>, <NUM> are assembled and vacuum bagged at the stringer assembly station <NUM>. At <NUM>, the assembled stringer components <NUM>, <NUM>, <NUM> are cured.

Embodiments of the disclosure may find use in a variety of potential applications, particularly in the transportation industry, including for example, aerospace, marine, automotive applications and other application where contoured elongate composite members, such as stringers, spars and beams, may be used. Thus, referring now to <FIG>, embodiments of the disclosure may be used in the context of an aircraft manufacturing and service method <NUM> as shown in <FIG> and an aircraft <NUM> as shown in <FIG>. Aircraft applications of the disclosed embodiments may include, for example, without limitation, stringers, spars, beams and similar structural members. During pre-production, exemplary method <NUM> may include specification and design and <NUM> of the aircraft <NUM> and material procurement <NUM>. During production, component and subassembly manufacturing <NUM> and system integration <NUM> of the aircraft <NUM> takes place. Thereafter, the aircraft <NUM> may go through certification and delivery <NUM> in order to be placed in service <NUM>. While in service by a customer, the aircraft <NUM> is scheduled for routine maintenance and service <NUM>, which may also include modification, reconfiguration, refurbishment, and so on.

As shown in <FIG>, the aircraft <NUM> produced by exemplary method <NUM> may include an airframe <NUM> with a plurality of systems <NUM> and an interior <NUM>. Examples of high-level systems <NUM> include one or more of a propulsion system <NUM>, an electrical system <NUM>, a hydraulic system <NUM> and an environmental system <NUM>. Any number of other systems may be included. Although an aerospace example is shown, the principles of the disclosure may be applied to other industries, such as the marine and automotive industries.

Systems and methods embodied herein may be employed during any one or more of the stages of the production and service method <NUM>. For example, components or subassemblies corresponding to production process <NUM> and <NUM> may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft <NUM> is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the production stages <NUM> and <NUM>, for example, by substantially expediting assembly of or reducing the cost of an aircraft <NUM>. Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while the aircraft <NUM> is in service, for example and without limitation, to maintenance and service <NUM>.

In some examples, there is disclosed a method of fabricating a contoured composite blade stringer, comprising: laying up a plurality of composite charges at a layup station; rolling up each of the composite charges; transporting each of the rolled up composite charges from the layup station to a forming station; unrolling each of the composite charges at the forming station; forming each of the composite charges into a contoured stringer component; transporting the stringer components from the forming station to an assembly station; and assembling the stringer components at the assembly.

Laying up a plurality of composite charges may include: unrolling a continuous flexible film onto a substrate; laying up composite plies on the flexible film; and wherein rolling up each of the composite charges includes rolling up the flexible film along with the composite charges onto a roll, and transporting the rolled up composite charges includes transporting the roll from the layup station to the forming station.

The method may further comprise: adjusting a shape of a forming mandrel to match or to substantially match the contour of the composite blade stringer; and forming each of the composite charges includes placing the composite charge on the forming mandrel and forming the composite charge over the forming mandrel.

Forming each of the composite charges may include: clamping a first section of the composite charge against a first portion of the forming mandrel using a first forming member; and forming a second section of the composite charge onto a second portion of the forming mandrel using a second forming member.

Assembling the stringer components may include: clamping two of the contoured stringer components together; installing a filler between the two contoured stringer components; and placing a third stringer component on top of the two contoured stringer components.

The method may further comprise: vacuum bagging the stringer components; and curing the stringer components.

Unrolling each of the composite charges may include unrolling the composite charges onto a table at an unloading position at the forming station, and moving the table to a standby position adjacent former; forming each of the composite charges includes moving the table from the standby position to a forming position beneath the former; transporting the stringer components from the forming station includes removing the formed composite charge from the table; and wherein the method further includes returning the table to the unloading position.

Unrolling each of the composite charges may include unrolling each of the composite onto a table; and forming each of the composite charges includes moving the table to a forming position beneath a former, moving the former down into contact with the composite charge and vacuum forming the composite charge over a forming mandrel.

As used herein, the phrase "at least one of", when used with a list of items, means different combinations of one or more of the listed items may be used and only one of each item in the list may be needed. For example, "at least one of item A, item B, and item C" may include, without limitation, item A, item A and item B, or item B. The item may be a particular object, thing, or a category. In other words, at least one of means any combination items and number of items may be used from the list but not all of the items in the list are required.

Claim 1:
A method of fabricating a contoured composite stiffener (<NUM>) comprising multiple assembled components (<NUM>, <NUM>, <NUM>), the method comprising:
assembling (<NUM>) a composite charge (<NUM>), including laying up at least one composite ply, for each component of the multiple assembled components (<NUM>, <NUM>, <NUM>);
rolling (<NUM>) the composite charges (<NUM>) onto a roll (<NUM>);
transporting (<NUM>) the roll (<NUM>) having the composite charges (<NUM>) thereon to a forming station (<NUM>) including a reconfigurable forming mandrel (<NUM>);
for each of the composite charges:
configuring (<NUM>) a shape of the reconfigurable forming mandrel (<NUM>) to substantially match a contour of the composite stiffener (<NUM>);
configuring a reconfigurable former (<NUM>) to substantially match the contour of the composite stiffener (<NUM>);
placing (<NUM>) the composite charge (<NUM>) on the reconfigurable forming mandrel (<NUM>), including unrolling the composite charge (<NUM>) from the roll (<NUM>) at the forming station (<NUM>);
forming (<NUM>) the composite charge (<NUM>) on the reconfigurable forming mandrel (<NUM>),
wherein forming the composite charge (<NUM>) on the reconfigurable forming mandrel (<NUM>) is performed using the reconfigurable former (<NUM>), and configuring the shape of the reconfigurable forming mandrel (<NUM>) includes:
adjusting a reconfigurable mandrel support (<NUM>) to generally match the contour of the composite stiffener (<NUM>),
loading the reconfigurable forming mandrel (<NUM>) onto the reconfigurable mandrel support (<NUM>), and
configuring the shape of the reconfigurable forming mandrel to substantially match the contour of the reconfigurable mandrel support (<NUM>); and
transporting the reconfigurable forming mandrel (<NUM>) having the formed composite charge (<NUM>) thereon to an assembly station (<NUM>); and
assembling the formed composite charges (<NUM>), corresponding to the multiple assembled components (<NUM>, <NUM>, <NUM>), at the assembly station (<NUM>) to form the composite stiffener (<NUM>).