Patent Description:
What is needed are new methods and devices for supporting of variety of different composite stringers after forming and prior to curing.

Document <CIT>, according to its abstract, discloses systems and methods for utilizing support tools for forming laminates. One embodiment is a system that includes a pair of dies that hold a multi-layer laminate over a gap, a male die that presses the laminate into the gap causing the laminate to change shape, and a support tool inserted into the gap beneath the laminate. The support tool includes a base that extends in a lengthwise direction, struts fixedly attached to the base that project upward from the base and are distributed along the lengthwise direction, and a cap that is slidably attached to the struts, and that covers the struts to form an upper surface of the support tool. Each of the struts rises from the base to the cap.

Document <CIT>, according to its abstract, discloses a flexible punch and die to form a flat composite laminate charge into a stiffener having a desired cross sectional shape. A desired contour is formed in the stiffener by bending the punch and die.

The present disclosure provides a post-forming processing device for supporting pre-cured composite stringers prior to curing having the features disclosed at claim <NUM>. The dependent claims outline advantageous forms of embodiment of the device.

Furthermore, the present disclosure describes another post-forming processing device for supporting pre-cured composite stringers prior to curing having the features disclosed at claim <NUM>. The dependent claims outline advantageous forms of embodiment of the device.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the presented concepts. In some examples, the presented concepts are practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail so as to not unnecessarily obscure the described concepts. While some concepts will be described in conjunction with the specific examples, it will be understood that these examples are not intended to be limiting.

Composite stringers and other shaped composite structures are used for many applications, such as aircraft, land vehicles, and the like. Fabrication of these composite structures involves various handling and processing of - shaped components, such as trimming, inspection, bladder installations, and such. Prior to curing, these shaped components require sufficient support to retain the shape, which can be challenging due to differences in shapes and sizes of these - components. For example, a modern aircraft uses hundreds of different composite stringers, which have different sizes, cross-sectional shapes, in-plane bends, and/or out-of-plane bends. Providing a dedicated support for each type of these composite stringers is challenging and expensive, adding to an already large number of specialized tools used in fabrication of composite stringers.

<FIG> illustrate two process flowcharts representing different examples of fabrication a composite stringer and corresponding tools used for various operations. <FIG> are presented to provide some context and general overview of key components, tools, and steps. In both examples, the process starts with forming device <NUM> shaping composite layup <NUM>, thereby forming - composite stringer <NUM>. Curing device <NUM> then cures - composite stringer <NUM>, thereby forming composite stringer <NUM>. - composite stringer <NUM> prior to curing and composite stringer <NUM> have the generally same shape, but different material and mechanical properties. For example, the resin of - composite stringer <NUM> prior to curing is not fully crosslinked or not as cross-inked as the resin of composite stringer <NUM>. As such, composite stringer <NUM> prior to curing is still able to change the shape and requires support before curing.

Both forming device <NUM> and curing device <NUM> are specifically shaped to accommodate a particular design of composite stringer <NUM>. Therefore, either one or both of forming device <NUM> and curing device <NUM> can be used for supporting - composite stringer <NUM> prior to curing after completing the forming operation and before initiating the curing operation, which corresponds to the example shown in <FIG>. However, this approach occupies one or both forming device <NUM> and curing device <NUM> for operations that are not core functions of these devices. Furthermore, many of these operations and even storage of - composite stringer <NUM> prior to curing may take significant periods of time. As a result, the throughput of one or both forming device <NUM> and curing device <NUM> can be limited by these intermediate operations and storage associated with - composite stringer <NUM> prior to curing.

Referring to <FIG>, post-forming processing device <NUM> is used to receive - composite stringer <NUM> prior to curing after - composite stringer <NUM> prior to curing is formed / shaped. Post-forming processing device <NUM> is also used to support - composite stringer <NUM> prior to curing up until the curing operation. Post-forming processing device <NUM> effectively relieves forming device <NUM> and curing device <NUM>, increasing their processing throughputs. Post-forming processing device <NUM> is used for various operations, performed on - composite stringer <NUM> prior to curing, and, in some examples, for storing - composite stringer <NUM> prior to curing.

However, if a post-forming processing device is specifically and permanently shaped for accommodating the shape of each specific composite stringer, then the numbers of such post-forming processing devices would be the same as the number of different stringers. This approach is not desirable from a space and cost savings perspective and can complicate the overall process by requiring a large number of additional tools. Furthermore, post-forming processing devices, which are specifically and permanently shaped, may not be always stackable due to the design variations, which complicates their storage. It should also be noted that the supply base is limited based on complexity of the post-forming processing device. Also, <NUM>-D geometry increases complexity for shuttling the stringers around. Finally, <NUM>-D geometry likely increases weight which will inhibit manual handling for a variety of reasons including maintenance.

Design variations of composite stringers or, more specifically, different examples of composite stringer <NUM> prior to curing are shown in <FIG>. In each example, composite stringer <NUM> comprises flange portions <NUM>, which define contact surface <NUM>. Contact surface <NUM> is used for connecting the composite stringer, formed from - composite stringer <NUM> prior to curing, to other components, e.g., a composite skin of an aircraft. These other components define the shape of contact surface <NUM>. In some examples, contact surface <NUM> is planar. Alternatively, contact surface <NUM> and, more generally, the entire stringer has an out-of-plane bend.

Each of - composite stringers <NUM> prior to curing also comprises hat portion <NUM>, which interconnects and is positioned between flange portions <NUM>. Hat portion <NUM> extends away from contact surface <NUM>, defining stringer cavity <NUM>. Hat portion <NUM> is defined by the height (H) of hat portion <NUM>, which is defined as a maximum deviation from contact surface <NUM>. Hat portion <NUM> is also defined by the width (W) of hat portion <NUM>, which is defined as the gap between flange portions <NUM>.

Referring to <FIG>, in some examples, hat portion <NUM> is formed by straight walls. Alternatively, in some examples, hat portion <NUM> is formed by a continuous curved wall, e.g., as shown in <FIG> illustrates an example where hat portion <NUM> is formed by a combination of straight and curved walls. <FIG> illustrate that - composite stringers <NUM>, shown in these figures, require different types of support from post-forming processing device <NUM>. Furthermore, <FIG> illustrate that - composite stringers <NUM> are not stackable. Therefore, if permanently-rigid supports are used for these - composite stringers, these supports will not be stackable either. For purposes of differentiating composite stringers, an example shown in <FIG> may be referred to as additional - composite stringers <NUM>. Processing different types of - composite stringers prior to curing using the same post-forming processing device <NUM> is described below with reference to <FIG>.

Described methods and devices are used for supporting of variety of different composite stringers, such as ones shown in <FIG>. More specifically, the same post-forming processing device is configured to support - composite stringers prior to curing with different cross-sectional profiles of their hat portions. Specifically, a post-forming processing device comprises a channel and a support structure, at least partially extending within the channel. The support structure is configured to conform to each of differently shaped hat portions the - composite stringers prior to curing and to retain the shape of these hat portions while providing the support. In some example, the support structure is made from a flexible material that conforms to any shape of the hat portions.

Within examples of the present disclosure, the disclosed post-forming processing device is used for supporting different - composite stringers prior to curing while various operations are performed on these stringers, such as stringer trimming, inspection, installation of bladders and noodles, and the like. Furthermore, in some examples, the disclosed post-forming processing device is used for storing - composite stringers prior to curing. Overall, adding the disclosed post-forming processing device into the overall process flow allows increasing processing throughputs of other devices, such as forming devices and curing devices. Overall, the disclosed post-forming processing devices provide high rate automation of stringer installation by merging the gap between forming and curing devices with these post-forming processing devices.

The described methods also incorporate alignment fittings to ensure the proper alignment between the stringer and the bladder for dead end fittings. Offset of the bladder helps to provide proper support and functionality during cure. For example, in some instances, a bladder is terminated inside of the edge of the part. Specific examples include door structures, window structures, and convergence structures (e.g., aircraft structures with pointy ends).

It should be noted that the cavity is used for forming stringer, accommodate both a stringer and a bladder. If the bladder does not extend past the stringer, the bladder will either interfere or leave an unacceptably large gap inside the tool. Since the bladder is aligned and locked to the stringer at the kitting stage, it is beneficial for that the bladder be indexed in the correct position to avoid rework at later stages.

Additionally, some bladders receive one or more layers of material wrapped around these bladders prior to insertion to corresponding stringers. In some examples, this assembly includes a glass ply, aligned to the end of the stringers to add the corrosion protection inside the stringer. In other examples, this assembly includes a carbon wrap, which adds strength to the stringer. In these later examples, the bladder wrap is aligned with the stringer.

<FIG> is a schematic cross-sectional view of post-forming processing device <NUM> for supporting - composite stringers <NUM>, in accordance with some examples. Post-forming processing device <NUM> comprises base <NUM>, support structure <NUM>, and cover <NUM>.

Base <NUM> is formed from a rigid material, such as carbon fiber, aluminum, a pultruded polyester/glass solution, and the like. Base <NUM> comprises support surface <NUM>, which faces cover <NUM>, when cover <NUM> is present. Support surface <NUM> is configured to seal against cover <NUM> and, in some examples, comprises one or more sealing features. During the operation of post-forming processing device <NUM>, support surface <NUM> is used to support flange portions <NUM> of stringer <NUM>, e.g., by compressing flange portions <NUM> between support surface <NUM> and cover. In some examples, support surface <NUM> is planar. In general, support surface <NUM> conforms to the shape of flange portions <NUM> of stringer <NUM>.

Base <NUM> also comprises channel <NUM>, partially extending through base <NUM> and having opening <NUM>. Opening <NUM> separates two portions of support surface <NUM>. As shown in <FIG>, channel <NUM> has a channel width (CW) and a channel height (CH). The channel width (CW) is measured in the direction parallel to support surface <NUM> (along the Y axis). The channel height (CH) is measured in the direction perpendicular to support surface <NUM> (along the Z axis). In some examples, the channel width (CW) is constant along the length (the X axis (see, e.g., <FIG>)) of base <NUM>. In the same or other examples, the channel height (CH) is constant along the length (the X axis) of base <NUM>. In some examples, the channel width (CW) is constant along the channel height (the Z axis) as, for example, shown in <FIG>. This type of channel <NUM> may be referred to as a straight channel. Alternatively, the channel width (CW) differs along the channel height (the Z axis) as, for example, shown in <FIG>. In this example, the channel width (CW) is the greatest at opening <NUM>. This type of channel <NUM> may be referred to as a tapered channel and allows for stacking post-forming processing device <NUM>.

Channel <NUM> is used to accommodate hat portion <NUM> of - composite stringer <NUM> prior to curing when - composite stringer <NUM> prior to curing is supported using post-forming processing device <NUM>. Referring to <FIG>, hat portion <NUM> protrudes into channel <NUM>, while flange portions <NUM> rest on support surface <NUM>. It should be noted that the same post-forming processing device <NUM> is used for supporting different types of composite stringers <NUM> prior to curing, which may have different shapes and sizes of hat portions <NUM>. As such, the channel width (CW) is larger than the width of hat portions <NUM> of - composite stringers <NUM> or, more specifically, larger than the width of the widest hat portion <NUM> among all - composite stringers <NUM> prior to curing, processed on post-forming processing device <NUM>. For purposes of this disclosure, the width of hat portion <NUM> is defined as the largest width, e.g., when hat portion <NUM> has a tapered or curved cross-section. Furthermore, the channel height is larger than the height of hat portion <NUM> of composite stringers <NUM> prior to curing or, more specifically, larger than the height of the tallest hat portion <NUM> among all - composite stringers <NUM> prior to curing, processed on post-forming processing device <NUM>. In general, the cross-sectional profile of channel <NUM> is sufficient to accommodate any hat portion <NUM> of stringer <NUM>, processed using post-forming processing device <NUM>.

While <FIG> illustrate a rectangular cross-sectional profile of channel <NUM>, any cross-sectional profile capable of accommodating hat portions <NUM> of - composite stringers <NUM> prior to curing is within the scope of the present disclosure, such as tapered profile shown in <FIG>, semi-circular profile, and the like. In some examples, the cross-sectional profile of channel <NUM> corresponds to the cross-sectional profile of hat portions <NUM>, e.g., both are tapered.

Referring to <FIG>, support structure <NUM> at least partially extends within channel <NUM> and along the length of channel <NUM>. In some examples, support structure <NUM> is configured to conform to each hat portion <NUM> and to retain the cross-sectional shape of that hat portion <NUM> when - composite stringers <NUM> prior to curing is supported by and processed using post-forming processing device <NUM>. It should be noted that the same support structure <NUM> is used for different types and profiles of hat portion <NUM>. Support structure <NUM> is able to conform to these different types and profiles while providing sufficient support.

In some examples, support structure <NUM> is formed from an elastic material, configured to change the shape when conforming to different types of hat portions <NUM>. Some examples of suitable elastic materials include, but are not limited to, latex, silicone (e.g., peroxide or platinum cured silicon), and other like materials. Some considerations for material selection includes weight, clean-ability, solvent resistance, stiffness, tear strength, elongation to failure, and hardness.

In accordance with independent claim <NUM>, support structure <NUM> is attached to base <NUM> at side walls of channel <NUM> as, e.g., is schematically shown in <FIG>. In these examples, support surface <NUM> remains exposed and available for interfacing with flange portions <NUM> of - composite stringers <NUM>. In other words, support structure <NUM> does not interfere when flange portions <NUM> are positioned on support surface <NUM>, e.g., compressed between support surface <NUM> and cover <NUM>. These examples are schematically shown in <FIG>.

In accordance with independent claim <NUM>, support structure <NUM> comprises a plastically deformable material. More specifically, support structure <NUM> is co-formed or co-shaped with one of composite stringers <NUM> prior to curing and then retains the shape of this stringer while supporting this stringer. For example, the shape of support structure <NUM> is initially different than that of - composite stringer <NUM> prior to curing. It should be noted that at this stage - composite stringer <NUM> is not yet formed. Both support structure <NUM> and a composite layup are loaded into a forming device, various examples of which are described below, and the shape of support structure <NUM> is adjusted, while - composite stringer <NUM> prior to curing is being formed. Hence, support structure <NUM> is co-formed or co-shaped with - composite stringer <NUM> prior to curing.

This shape is retained by support structure <NUM> during various operation of post-forming processing device <NUM> while supporting this particular stringer. In some examples, the shape is retained while processing multiple stringers of the same type, e.g., the same cross-sectional shape of hat portions. When a different type of stringer is to be supported, the shape of support structure <NUM> is changed, e.g., by co-forming or shaping with that other stringer. These examples are schematically shown in <FIG>.

Referring to <FIG>, in some examples, support structure <NUM> comprises support flanges <NUM> extending over support surface <NUM> of base <NUM> and outside channel <NUM>. Similar to a portion of support structure <NUM>, extending into channel <NUM> and supporting hat portions <NUM> of stringer <NUM>, support flanges <NUM> are specifically shaped to support flange portions <NUM> of stringer <NUM>. In some examples, the shape of support flanges <NUM> is different from the shape of support surface <NUM>. Therefore, the same post-forming processing device <NUM> may be used for supporting stringers with different shapes of flange portions.

In some examples, support structure <NUM> is removable from base <NUM>. For example, support structure <NUM> is removed from base <NUM> to change the shape of support structure <NUM>. In some examples, different types of support structure <NUM> are used with the same base <NUM>.

Cover <NUM> is configured to attach to base <NUM>, such that the corresponding one of composite stringers <NUM> prior to curing is positioned between cover <NUM> and base <NUM> while supported by post-forming processing device <NUM>. More specifically, flange portions <NUM> of composite stringer <NUM> prior to curing are positioned and, in some examples, are compressed between cover <NUM> and support surface <NUM> as, for example, is schematically shown in <FIG>. Cover <NUM> is configured to seal against base <NUM>. Specifically, cover <NUM> comprises vacuum seal <NUM>, which engages seal receiver <NUM>.

In some examples, base <NUM> comprises pass-through <NUM>, fluidically coupled with channel <NUM> and configured to control pressure inside channel <NUM> and under support structure <NUM>. For example, pass-through <NUM> is used to maintain the pressure under support structure <NUM> to be the same as in the environment, e.g., when hat portion <NUM> of composite stringer <NUM> prior to curing is inserted into channel <NUM> and engages support structure <NUM> or, more specifically, when hat portion <NUM> pushes support structure <NUM> deeper into channel <NUM> thereby reducing the volume under support structure <NUM>.

In some examples, post-forming processing device <NUM> further comprises flexible insert <NUM> as, e.g., shown in <FIG>. Flexible insert <NUM> is positioned with channel <NUM> and under support structure <NUM> and is used to provide additional support to hat portion <NUM>. Flexible insert <NUM> allows using support structure <NUM> that are very flexible and able to conform to a larger variation of hat portion <NUM> than, for example, when support structure <NUM> is used without flexible insert <NUM>. In some examples, flexible insert <NUM> is made from an elastomeric rubber, such as MOSITES® rubber, latex, or something similar.

Referring to <FIG>, in some examples, post-forming processing device <NUM> comprises pass-through bladder seal <NUM> and dead end bladder seal <NUM>. It should be noted that bladder <NUM>, which is further described below with reference to <FIG>, is a tube made, e.g., from silicone, VITON®, or other like materials. In some examples, the material of bladder <NUM> is reinforced or layered. During processing, bladder <NUM> is vented to the autoclave atmosphere during cure and vented to the ambient atmosphere during any compaction/vacuum bag. As such, in some examples, one end of bladder <NUM> comprises a fitting with a vent hole. Pass-through bladder seal <NUM>, shown in <FIG>, connects this fitting allowing bladder <NUM> to vent, when bladder <NUM> is inside post-forming processing device <NUM>. In some examples, post-forming processing device <NUM> comprises pass-through bladder seals on both ends.

<FIG> is a process flowchart corresponding to a non-claimed method <NUM> of fabricating composite stringer <NUM>, see, e.g., <FIG>, in accordance with some examples. Composite stringer <NUM> should be differentiated from - composite stringer <NUM> prior to curing, which is an intermediate structure used to form composite stringer <NUM>. As such, in some examples, - composite stringer <NUM> and composite stringer <NUM> have the same size and shape. Therefore, <FIG> are representative of both - composite stringer <NUM> prior to curing and composite stringer <NUM>. In some examples, composite stringer <NUM> comprises a fiber reinforced composite material, which may be also referred to as a reinforced composite material. This type of material comprises one or more non-homogeneous polymer-based components and one or more non-polymeric based components (e.g., carbon-fibers). Method <NUM> is described in greater detail below with reference to <FIG> and <FIG>.

Method <NUM> comprises forming (block <NUM>) - composite stringer <NUM> prior to curing, e.g., using composite layup <NUM>. This operation is performed using forming device <NUM> (shown in <FIG>), which is different from post-forming processing device <NUM>, used in later operation (shown in <FIG>). As noted above, post-forming processing device <NUM> increases throughput of forming device <NUM> since various later operations are performed using post-forming processing device <NUM>.

In some examples, composite layup <NUM> comprises an uncured pre-impregnated reinforcing tape or fabric, which may be referred to as a prepreg. The tape or fabric comprises fibers, such as graphite fibers, embedded within a matrix material, such as a polymer or, more specifically, an epoxy or phenolic resin. In some examples, the tape or fabric is unidirectional or woven depending on the design and the degree of reinforcement desired in the resulting composite stringer <NUM>.

During the forming operation (block <NUM>), composite layup <NUM> is positioned on forming device <NUM> as, e.g., is shown in <FIG>. In some examples, support structure <NUM> is positioned between composite layup <NUM> and forming device <NUM>, e.g., when support structure <NUM> is co-formed together with - composite stringer <NUM> prior to curing. These examples are further described below with reference to block <NUM>. Forming device <NUM> comprises forming base <NUM> with forming cavity <NUM>, which defines the shape of hat portion <NUM> of - composite stringer prior to curing. Referring to <FIG>, forming device <NUM> also comprises forming die <NUM>, which pushes a part of composite layup <NUM> into forming cavity <NUM> and against the walls of forming cavity <NUM>.

Upon completion of this operation, composite layup <NUM> is formed into - composite stringer <NUM>. - composite stringer <NUM> prior to curing comprises hat portion <NUM>, which is disposed between forming die <NUM> and the walls of forming cavity <NUM>. - composite stringer <NUM> prior to curing also comprises flange portions <NUM>, which extend outside of forming cavity <NUM> and, e.g., conform to forming surface <NUM> of forming base <NUM>. In some examples, forming die <NUM> comprises specially configured bladders, pressing on flange portions <NUM>. These bladders are pressurized and contact flange portions <NUM> prior to forming hat portion <NUM>, in some examples to different pressure level to allow composite layup <NUM> to slip on forming surface <NUM> while hat portion <NUM> is being formed.

In some examples, forming - composite stringer <NUM> prior to curing on forming device comprises forming (block <NUM>) support structure <NUM> of post-forming processing device <NUM>. In some examples, support structure <NUM> is shaped in a separate operation from - composite stringer <NUM> prior to curing. Alternatively, support structure <NUM> and composite stringer <NUM> prior to curing are co-formed or co-shaped in the same overall operation, e.g., the operation represented by block <NUM> is a part of the operation represented by block <NUM>, as shown in <FIG>. In other words, support structure <NUM> is placed into forming device <NUM> together with composite layup <NUM>. At this stage, the shape of support structure <NUM> is different than the shape of - composite stringer <NUM> prior to curing, which will be formed on and defined by forming device <NUM>. For example, support structure <NUM> has been previously used for supporting another - composite stringer prior to curing, which has a different shape. During concurrent operations represented by block <NUM> and block <NUM>, - composite stringer <NUM> prior to curing is formed while support structure <NUM> is also co-formed or co-shaped. This support structure forming operation (block <NUM>) may be also referred to as a shape changing operation.

In some examples, method <NUM> also comprises trimming of - composite stringer <NUM> prior to curing, e.g., cutting a portion of - composite stringer <NUM> prior to curing. For example, an ultrasonic knife is used for cutting.

Method <NUM> proceeds with transferring (block <NUM>) - composite stringer <NUM> prior to curing from forming device <NUM> to post-forming processing device <NUM>. For instance, the transfer of - composite stringer <NUM> prior to curing from forming device <NUM> to post-forming processing device <NUM> is shown in <FIG>. Various examples of post-forming processing device <NUM> are described above. In some examples, - composite stringer <NUM> prior to curing is transferred unsupported. Alternatively, - composite stringer <NUM> prior to curing is transferred together with support structure <NUM>.

In some examples, the transferring operation comprises controlling pressure inside channel <NUM> of base <NUM>. For example, inserting hat portion <NUM> of - composite stringer <NUM> prior to curing into channel <NUM> may cause displacing of air from channel <NUM>, e.g., through pass-through <NUM>.

In some examples, the transferring operation comprises stretching (block <NUM>) support structure <NUM> of post-forming processing device <NUM>. In these examples, support structure <NUM> is formed from an elastic material that conforms to the shape of hat portion <NUM> of - composite stringer <NUM> prior to curing as hat portion is inserted into channel <NUM>. More specifically, the elastic material is configured to change the shape when conforming to each of hat portions <NUM>. As noted above, in some examples, hat portions <NUM> have different cross-sectional shapes. This stretching feature as, e.g., is shown in <FIG>, of support structure <NUM> allows supporting - composite stringers <NUM> with different sizes of hat portions <NUM>.

In some examples, the transferring operation comprises adjusting (block <NUM>) the shape of post-forming processing device <NUM>. <FIG> illustrate base <NUM> of post-forming processing device <NUM>, which has a pivot point, defined by first axis <NUM>. Other components of post-forming processing device <NUM>, such as support structure <NUM>, are not shown for simplicity. The pivot point allows base <NUM> to have an in-plane bending and accommodate both straight - composite stringers prior to curing (in the configuration shown in <FIG>) and - composite stringers prior to curing with an in-plane bend (in the configurations shown in <FIG>). While only one pivot point is shown in <FIG>, one having ordinary skill in the art would understand that any number of pivot points may be present. Furthermore, in some examples, post-forming processing device <NUM> has an out-of-plane bending functionality. It should be noted that some degrees of bending, especially localized bending, of - composite stringers prior to curing can be accommodated by the side of channel <NUM> within base <NUM>, without bending base <NUM>.

In some examples, method <NUM> comprises inspecting (block <NUM>) - composite stringer <NUM> prior to curing. The inspection is performed while - composite stringer <NUM> prior to curing is positioned on post-forming processing device <NUM>. For example, the inspection involves checking the surface of - composite stringer <NUM> prior to curing for wrinkles, bubbles, foreign object debris (FOD), loose fibers, wrinkles, and shape. It should be noted that the inspection operation is performed away from forming device <NUM> and curing device <NUM>, thereby allowing other - composite stringers prior to curing to be processes on these devices and increasing the overall process throughput.

Method <NUM> comprises installing (block <NUM>) bladder <NUM> on - composite stringer <NUM> prior to curing as, e.g., schematically shown in <FIG>. Bladder <NUM> is installed while composite stringer <NUM> is positioned on post-forming processing device <NUM>. In some example, bladder <NUM> is wrapped into a bladder warp, which is later cured into the skin of the stringer when bladder <NUM> is removed. Bladder <NUM> is used during curing operation to provide support inside of - composite stringer <NUM> prior to curing. In some examples, bladder <NUM> is a solid object composed of silicone, urethane, or similar materials, including any combination thereof. In some examples, bladder <NUM> is shaped to substantially correspond with - composite stringer <NUM> prior to curing.

Method <NUM> comprises installing (block <NUM>) noodle <NUM> at an interface between bladder <NUM> and - composite stringer <NUM> and within the plane of support surface <NUM> of base <NUM> as, e.g., schematically shown in <FIG>. This installing operation is performed while - composite stringer <NUM> prior to curing is positioned on post-forming processing device <NUM>. Noodle <NUM> is also referred to as a radius filler.

In some examples, method <NUM> comprises compacting (block <NUM>) - composite stringer <NUM> prior to curing, while - composite stringer <NUM> prior to curing is positioned on post-forming processing device <NUM>. For example, the compacting operation involves sealing cover <NUM> of post-forming processing device <NUM> against base <NUM> of post-forming processing device <NUM> as, for example, is schematically shown in <FIG>. In some examples, the compacting operation further comprises contacting at least flange portions <NUM> of composite stringer <NUM> prior to curing with cover <NUM> of post-forming processing device <NUM>.

In some examples, method <NUM> comprises staging and transporting - composite stringer <NUM> prior to curing. These operations are performed while - composite stringer <NUM> is positioned on post-forming processing device <NUM>. Furthermore, post-forming processing device <NUM> is used for storing - composite stringer <NUM> prior to curing, while providing support to - composite stringer <NUM>.

Method <NUM> proceeds with transferring (block <NUM>) - composite stringer <NUM> prior to curing from post-forming processing device <NUM> to curing device <NUM>. For instance, the transfer of - composite stringer <NUM> prior to curing from post-forming processing device <NUM> to curing device <NUM> is shown in <FIG>. In some examples, - composite stringer <NUM> prior to curing is transferred together with bladder <NUM> and/or noodle <NUM>, which are installed onto - composite stringer <NUM> prior to curing while - composite stringer <NUM> prior to curing was positioned on post-forming processing device <NUM>.

Method <NUM> comprises curing (block <NUM>) - composite stringer <NUM> prior to curing on curing device <NUM>, thereby forming composite stringer <NUM> as, for example, is schematically shown in <FIG> and <FIG>. For example, - composite stringer <NUM> prior to curing, shown in <FIG>, is subjected to heat and pressure to cross-link the resin within composite stringer <NUM> prior to curing. Unlike - composite stringer <NUM> prior to curing, composite stringer <NUM>, shown in <FIG>, does not require the level of support needed for composite stringer <NUM> prior to curing. As such, post-forming processing device <NUM> is not used for composite stringer <NUM>.

In some examples, various operations of method <NUM> are repeated (decision block <NUM>) with additional - composite stringer <NUM> prior to curing, e.g., one example of which is shown in <FIG>. Specifically, additional - composite stringer <NUM> prior to curing has a different design than - composite stringer <NUM> prior to curing, previously processed using the same post-forming processing device <NUM>. Various different designs for - composite stringers prior to curing are shown in <FIG>. Other example designs for the composite stringer prior to curing are possible as well.

Specifically, method <NUM> comprises forming <NUM> an additional - composite stringer <NUM> prior to curing on an additional forming device. Unlike post-forming processing device <NUM>, which can be universally used across a variety of different designs of - composite stringers prior to curing, forming devices are dedicated tools. In some examples, support structure <NUM> is reformed or reshaped during this operation of forming additional composite stringer <NUM> prior to curing. More specifically, support structure <NUM> has a different shape when supporting additional - composite stringer <NUM> prior to curing than when supporting - composite stringer <NUM> prior to curing.

Method <NUM> proceeds with transferring (block <NUM>) this additional - composite stringer <NUM> prior to curing from the forming device to post-forming processing device <NUM>. As noted above, additional - composite stringer <NUM> prior to curing has a different design and, more specifically, a different cross-sectional profile than - composite stringer <NUM> prior to curing.

In some examples, method <NUM> continues with installing an additional bladder on additional - composite stringer <NUM>, while additional - composite stringer <NUM> prior to curing is positioned on post-forming processing device <NUM>. Furthermore, a noodle is installed on additional - composite stringer <NUM> prior to curing, while additional - composite stringer <NUM> prior to curing is positioned on post-forming processing device <NUM>. However, these operations are optional.

Method <NUM> proceeds with transferring additional - composite stringer <NUM> prior to curing together with additional bladder and additional noodle from post-forming processing device <NUM> to an additional curing device and curing - composite stringer <NUM> prior to curing using additional curing device, thereby forming an additional composite stringer.

<FIG> is a process flowchart of a non-claimed method <NUM> of supporting composite stringer prior to curing <NUM> using post-forming processing device <NUM>, in accordance with some examples of the present disclosure. Method <NUM> comprises transferring (block <NUM>) - composite stringer <NUM> prior to curing to post-forming processing device <NUM> as, for example, is schematically shown in <FIG>. Various examples of composite stringer <NUM> prior to curing are described above. For example, - composite stringer <NUM> prior to curing comprises comprising hat portion <NUM>, which is supported upon the transfer of - composite stringer <NUM> to post-forming processing device <NUM>. Post-forming processing device <NUM> comprises base <NUM>, comprising channel <NUM>. Post-forming processing device <NUM> also comprises support structure <NUM>, at least partially extending within channel <NUM> and along the length of channel <NUM>.

When - composite stringer <NUM> prior to curing is transferred to post-forming processing device <NUM>, support structure <NUM> conforming to hat portion <NUM> of - composite stringer <NUM> prior to curing, as for, example, is schematically shown in <FIG>. More specifically, support structure <NUM> retains the cross-sectional shape of hat portion <NUM> of composite stringer <NUM> prior to curing while - composite stringer <NUM> prior to curing is positioned in post-forming processing device <NUM>. In some examples, support structure <NUM> is formed from a flexible material, providing this conformal supports.

In some examples, the transferring operation (block <NUM>) comprises stretching (block <NUM>) support structure <NUM> of post-forming processing device <NUM> as, for example, is schematically shown in <FIG>. In these examples, support structure <NUM> is formed from an elastic material that conforms to the shape of hat portion <NUM> of - composite stringer <NUM> prior to curing as hat portion is inserted into channel <NUM>. This stretching feature of support structure <NUM> allows supporting - composite stringers <NUM> prior to curing with different sizes of hat portions <NUM>.

In some examples, the transferring operation (block <NUM>) comprises adjusting (block <NUM>) the shape of post-forming processing device <NUM>. <FIG> illustrate base <NUM> of post-forming processing device <NUM>, which has a pivot point, defined by first axis <NUM>. Other components of post-forming processing device <NUM>, such as support structure <NUM>, are not shown for simplicity. The pivot point allows base <NUM> to have an in-plane bending and accommodate both straight - composite stringers prior to curing (in the configuration shown in <FIG>) and - composite stringers prior to curing with an in-plane bend (in the configurations shown in <FIG>). While only one pivot point is shown in <FIG>, one having ordinary skill in the art would understand that any number of pivot points may be present. Furthermore, in some examples, post-forming processing device <NUM> has an out-of-plane bending functionality. It should be noted that some degrees of bending, especially localized bending, of - composite stringers prior to curing can be accommodated by the side of channel <NUM> within base <NUM>, without bending base <NUM>.

In some examples, the transferring operation (block <NUM>) comprises positioning (block <NUM>) cover <NUM> of post-forming processing device <NUM> against base <NUM> of post-forming processing device <NUM> as, for example, is schematically shown in <FIG>. In some examples, cover <NUM> is sealed against base <NUM>. Furthermore, in some examples, this cover positioning operation (block <NUM>) compacts at least flange portions <NUM> of - composite stringer <NUM> prior to curing.

In some examples, the transferring operation (block <NUM>) comprises controlling (block <NUM>) pressure inside channel <NUM> of base <NUM>. For example, inserting hat portion <NUM> of - composite stringer <NUM> prior to curing into channel <NUM> may cause displacing of air from channel <NUM>, e.g., through pass-through <NUM>.

In some examples, method <NUM> comprises storing (block <NUM>) - composite stringer <NUM>. More specifically, - composite stringer <NUM> prior to curing is stored in post-forming processing device <NUM> prior to removing (block <NUM>) - composite stringer <NUM> prior to curing from post-forming processing device <NUM>.

Method <NUM> proceeds with removing (block <NUM>) - composite stringer <NUM> prior to curing from post-forming processing device <NUM>. For example, - composite stringer <NUM> prior to curing is transferred to curing device <NUM> as, for example, is schematically shown in <FIG>. Alternatively, - composite stringer <NUM> prior to curing is transferred to other equipment, e.g., for inspection.

Method <NUM> proceeds or, more specifically repeats, (decision block <NUM>) with transferring (block <NUM>) additional - composite stringer <NUM> prior to curing to post-forming processing device <NUM> as, for example, is schematically shown in <FIG>. Additional composite stringer <NUM> prior to curing comprising additional hat portion <NUM>, such that cross-sectional shape of additional hat portion <NUM> of additional - composite stringer <NUM> prior to curing, different from the cross-sectional shape of hat portion <NUM> of - composite stringer <NUM> prior to curing, shown in <FIG>. However, despite this difference in the cross-sectional shapes, support structure <NUM> of post-forming processing device <NUM> conforms to additional hat portion <NUM> of additional - composite stringer <NUM> prior to curing. Furthermore, support structure <NUM> retains the cross-sectional shape of additional hat portion <NUM> of additional - composite stringer <NUM> prior to curing.

In some examples, methods and systems described above are used on aircraft and, more generally, by the aerospace industry. Specifically, these methods and systems can be used during fabrication of aircraft as well as during aircraft service and maintenance.

Accordingly, the apparatus and methods described above are applicable for aircraft manufacturing and service method <NUM> as shown in <FIG> and for aircraft <NUM> as shown in <FIG>. During pre-production, method <NUM> includes specification and design <NUM> of aircraft <NUM> and material procurement <NUM>. During production, component and subassembly manufacturing <NUM> and system integration <NUM> of aircraft <NUM> takes place. Thereafter, aircraft <NUM> goes through certification and delivery <NUM> in order to be placed in service <NUM>. While in service by a customer, aircraft <NUM> is scheduled for routine maintenance and service <NUM>, which also includes modification, reconfiguration, refurbishment, and so on.

In some examples, each of the processes of method <NUM> is performed or carried out by a system integrator, a third party, and/or an operator, e.g., a customer. For the purposes of this description, a system integrator includes without limitation any number of aircraft manufacturers and major-system subcontractors; a third party includes without limitation any number of venders, subcontractors, and suppliers; and an operator can be an airline, leasing company, military entity, service organization, and so on.

As shown in <FIG>, aircraft <NUM> produced by method <NUM> includes airframe <NUM> with plurality of systems <NUM>, and interior <NUM>. Examples of systems <NUM> include one or more of propulsion system <NUM>, electrical system <NUM>, hydraulic system <NUM>, and environmental system <NUM>. Any number of other systems can be included. Although an aerospace example is shown, the principles of the examples described herein is applied to other industries, such as the automotive industry.

Claim 1:
A post-forming processing device (<NUM>) for supporting pre-cured composite stringers prior to curing (<NUM>), the pre-cured composite stringers prior to curing comprising hat portions (<NUM>), having cross-sections, different among the pre-cured composite stringers prior to curing, the post-forming processing device (<NUM>) comprising:
a base (<NUM>), comprising a channel (<NUM>), having a channel width and a channel height, wherein:
the channel width is larger than a width of the hat portions (<NUM>) of the pre-cured composite stringers prior to curing (<NUM>), and
the channel height is larger than heights of the hat portions (<NUM>) of the pre-cured composite stringers prior to curing (<NUM>);
a support structure (<NUM>), at least partially extending within the channel (<NUM>) and along a length of the channel (<NUM>) and configured to conform to each of the hat portions (<NUM>) and to retain a cross-sectional shape of each of the hat portions (<NUM>) when a corresponding one of the pre-cured composite stringers prior to curing (<NUM>) is supported by the post-forming processing device (<NUM>);
a cover (<NUM>), configured to attach to the base (<NUM>), such that the corresponding one of the pre-cured composite stringers prior to curing (<NUM>) is positioned between the cover (<NUM>) and the base (<NUM>) while supported by the post-forming processing device (<NUM>); and
wherein the support structure (<NUM>) comprises a plastically deformable material.