Patent Description:
Fabrication of large composite parts, such as components of aircraft, often may involve kitting, layup, assembly, and/or curing of elongate composite parts that may be many tens, or even over a hundred feet long (<NUM> feet = <NUM>,<NUM> meter). Fabrication of such elongate composite parts presents unique manufacturing challenges.

Document <CIT>, according to its abstract, states an apparatus and a method for providing pressure for bonding parts together. The apparatus may comprise a plurality of bladders independently actuatable to apply pressure for pushing a second part toward a first part having adhesive thereon. The apparatus may further comprise a frame supporting a plurality of reconfigurable bladder retainer devices positioned and angled such that the configuration of the bladders matches the contour of the second part. The bladders may expand and contract according to a sequence dictated by a control device, such that excess air and adhesive between the first and second part may be substantially squeegeed toward outer edges of the parts.

Document <CIT>, according to its abstract, states a molding apparatus for manufacturing a wind turbine blade component including a main mold body and a flexible bladder. The main mold body includes a shape defining surface for receiving composite material forming the blade component and a heat reservoir for heating the blade component during curing. The flexible bladder overlays and conforms to the shape of the blade component and is configured to receive heated liquid for heating the blade component during curing. One or both of the main mold body and the flexible bladder is divided into a plurality of zones that are independently controlled by a controller to maintain a generally uniform temperature of the blade component at each zone.

Document <CIT>, according to its abstract, states a material form-ing apparatus and method for shaping a material to a forming tool having complex contours. The material forming apparatus may comprise a bladder sealed to a support struc-ture, cooperatively forming a hollow space therebetween into which air or another gas may be pumped to inflate the bladder. The forming tool may comprise a protrusion of any shape to which the material may conform. The material may be placed between the bladder and the protrusion and the support structure may be actuated toward the forming tool. As the support structure progresses toward the forming tool, an area of material pressed against the protrusion by the bladder increases in an outward direction. A pressure regulator may regulate an amount of pressure applied to the material by the bladder as the bladder presses the material against the forming tool.

Traditional manufacturing methods for fabricating composite parts include manually locating a plurality of plies of composite material on a layup mandrel to form a composite layup, with each ply of the plurality of plies generally being coextensive with a remainder of the plurality of plies in the composite part. The composite layup subsequently is cured, on the layup mandrel, to form the composite part. While such traditional manufacturing methods may be effective at forming smaller composite parts, they may be inefficient when applied to forming larger composite parts. As an example, a manufacturing floor space needed to fabricate large composite parts utilizing traditional manufacturing methods may be substantial. As another example, an amount of time required to fabricate large composite parts utilizing traditional manufacturing methods may be quite large. As yet another example, there may be ergonomic concerns when large composite parts are fabricated manually.

Any of these manufacturing constraints may increase the cost of, or present safety challenges during, fabrication of the large composite part. Thus, there exists a need for improved composite part fabrication systems and methods.

Therefore, a system according to claim <NUM> as well as methods according to claim <NUM> and <NUM> are provided.

Systems and methods for incrementally forming a composite part are disclosed herein. The systems include a forming mandrel, which includes a forming surface. A surface profile of the forming surface corresponds to a surface profile of the composite part and the forming surface is configured to receive a ply of composite material. The systems also include a forming machine. The forming machine includes a forming bladder, which defines an internal volume, a pressure-regulating device, which is configured to regulate a pressure within the internal volume, and a positioning device, which is configured to selectively position the forming bladder relative to the forming surface at a plurality of selected locations. The forming bladder is configured to be inflated to a forming pressure and to press the ply of composite material against the forming surface at each of a plurality of selected locations to conform corresponding portions of the ply of composite material to the surface profile of the forming surface and at least partially define the composite part.

The methods include placing a ply of composite material on a forming surface of a forming mandrel and pressing a forming bladder against the ply of composite material at a selected location to press a selected portion of the ply of composite material against the forming surface and conform the selected portion of the ply of composite material to a surface profile of the forming surface. The methods also include repeating the pressing a plurality of times at a plurality of selected locations to selectively and operatively press the ply of composite material against the forming surface at each of the plurality of selected locations and to conform corresponding portions of the ply of composite material to the surface profile of the forming surface.

<FIG> provide examples of aircraft <NUM> that include one or more composite parts <NUM> that may be formed utilizing the systems and methods according to the present disclosure, of systems <NUM>, according to the present disclosure, for incrementally forming a composite part, and/or of methods <NUM>, according to the present disclosure, of incrementally forming the composite part. Elements that serve a similar, or at least substantially similar, purpose are labeled with like numbers in each of <FIG>, and these elements may not be discussed in detail herein with reference to each of <FIG>. Similarly, all elements may not be labeled in each of <FIG>, but reference numerals associated therewith may be utilized herein for consistency. Elements, components, and/or features that are discussed herein with reference to one or more of <FIG> may be included in and/or utilized with any of <FIG>.

In general, elements that are likely to be included in a given (i.e., a particular) embodiment are illustrated in solid lines, while elements that are optional to a given embodiment are illustrated in dashed lines. However, elements that are shown in solid lines are not essential to all embodiments, and an element shown in solid lines may be omitted from a given embodiment.

<FIG> is an example of an aircraft <NUM> that includes a composite structure <NUM> that may include a composite part <NUM> that may be at least partially constructed utilizing systems <NUM> and/or methods <NUM>, according to the present disclosure. <FIG> is an example of a wing <NUM> that may form a portion of aircraft <NUM>. Aircraft <NUM> may include a plurality of components, including an airframe <NUM>, a fuselage <NUM>, a fuselage barrel <NUM>, wing <NUM>, and/or a stabilizer <NUM>.

Composite structure <NUM> of aircraft <NUM> may include a plurality of plies <NUM> of composite material, which may form composite part <NUM> and/or which may form a portion of any suitable component of aircraft <NUM>. As an example, and as illustrated in <FIG>, aircraft <NUM> may include skin segments <NUM> that may form, cover, and/or be an outer surface of any suitable portion of aircraft <NUM> and/or a plurality of stringers <NUM> that, together with a plurality of frames <NUM>, may support an inner surface of skin segments <NUM>. As another example, and as illustrated in <FIG>, wing <NUM> may include a plurality of wing stringers <NUM>, which may extend along a length of the wing. Wing <NUM> also may include a plurality of ribs <NUM>, which also may be referred to herein as spars <NUM>. Wing stringers <NUM> and ribs <NUM> together may form and/or define at least a portion of an inner support structure <NUM> for wing <NUM>, which may support an inner surface <NUM> of skin segments <NUM> that cover wing <NUM>. These skin segments also may be referred to herein as wing skin segments <NUM>. It is within the scope of the present disclosure that skin segments <NUM> (or wing skin segments <NUM>), stringers <NUM>, frames <NUM>, wing stringers <NUM>, ribs <NUM>, and/or inner support structure <NUM> may be at least partially, or even completely, formed from plies <NUM> of composite material and/or may be a composite part <NUM> that may be formed utilizing the systems and/or methods disclosed herein.

<FIG> is a schematic representation of examples of a system <NUM>, according to the present disclosure, for incrementally forming a composite part. <FIG> is a less schematic profile view of a system <NUM>, according to the present disclosure, for incrementally forming a composite part <NUM>, while <FIG> is a less schematic side view of system <NUM> of <FIG> and <FIG> is a less schematic transverse cross-sectional view of system <NUM> of <FIG>. <FIG> may include and/or be more detailed representations of system <NUM> of <FIG>. As such, any structure, element, component, feature, and/or function that is discussed herein with reference to one of <FIG> may be included in and/or utilized with any of <FIG>.

System <NUM> includes a forming mandrel <NUM> that includes and/or defines at least one forming surface <NUM>. System <NUM> also includes a forming machine <NUM>, which may be adapted, configured, designed, and/or constructed to press one or more plies <NUM> of composite material against forming surface <NUM> to deform the one or more plies <NUM> and/or to conform the one or more plies <NUM> to a surface profile of forming surface <NUM>. In the context of system <NUM>, forming surface <NUM> may include those portion(s) of an outer surface of forming mandrel <NUM> that operatively contact ply <NUM> and/or that deform ply <NUM> when forming machine <NUM> presses ply <NUM> there against.

Forming machine <NUM> includes a forming bladder <NUM> that defines an internal volume <NUM>. As illustrated in solid lines in <FIG>, forming machine <NUM> also includes a pressure-regulating device <NUM> that is configured to regulate, control, establish, and/or maintain a pressure (e.g., a pressure that is greater than atmospheric pressure) within internal volume <NUM>. Forming machine <NUM> also includes at least one positioning device <NUM>, which is configured to selectively position and/or orient forming bladder <NUM> relative to, or with respect to, forming surface <NUM> of forming mandrel <NUM>. This may include orienting at least a portion of forming machine <NUM>, such as forming bladder <NUM> thereof, at a plurality of selected, or different, locations. As an example, <FIG> illustrates forming machine <NUM> in solid lines when at a first selected location and not operatively pressing ply <NUM> against forming surface <NUM>. In addition, <FIG> illustrates forming machine <NUM> in dash-dot lines when at a second selected location that is different from the first selected location and operatively pressing ply <NUM> against forming surface <NUM>.

As used herein, the phrases "operatively press," "operatively presses," and/or "operatively pressing," as well as the words "press," "presses," and/or "pressing," may indicate direct and/or indirect contact between a given ply <NUM> and forming surface <NUM> and/or forming bladder <NUM>. As an example, and while being pressed against forming surface <NUM> by forming bladder <NUM>, the given ply <NUM> may be in direct physical contact with forming surface <NUM>, with forming bladder <NUM>, and/or with both forming surface <NUM> and forming bladder <NUM>. As another example, and while being pressed against forming surface <NUM>, another ply <NUM>, or even another material and/or film, may extend between the given ply <NUM> and forming surface <NUM> and/or forming bladder <NUM>. As a more specific example, an intermediate film <NUM> may extend between the given ply <NUM> and forming bladder <NUM>.

During operation of system <NUM>, forming bladder <NUM> is configured to be inflated to a forming pressure, such as by pressure-regulating device <NUM> providing a fluid to internal volume <NUM>, and to selectively and operatively press ply <NUM> of composite material against forming surface <NUM> at each of the plurality of selected locations. This operative pressing of ply <NUM> against forming surface <NUM> may conform corresponding portions of ply <NUM> to the surface profile of forming surface <NUM>, thereby at least partially defining a composite part <NUM>. Generally, forming bladder <NUM> may be maintained at, or near, the forming pressure while ply <NUM> is pressed against forming surface <NUM>, as discussed in more detail herein with reference to process flow <NUM> of <FIG> and methods <NUM> of <FIG>. As such, pressure-regulating device <NUM> may be configured to permit fluid to leave forming bladder <NUM> responsive to a decrease in internal volume <NUM> and/or may add fluid to forming bladder <NUM> responsive to an increase in internal volume <NUM>.

Forming mandrel <NUM> may include and/or be any suitable structure that may have, define, and/or include forming surface <NUM>, and a surface profile of forming surface <NUM> may correspond to a surface profile, or a desired surface profile, of composite part <NUM>. As such, forming surface <NUM> may be adapted, configured, designed, and/or constructed to receive one or more plies <NUM> of composite material such that forming machine <NUM> may conform the one or more plies <NUM> of composite material to the surface profile of forming surface <NUM>.

As discussed, forming machine <NUM> may be configured for incremental forming of composite part <NUM>. As such, a surface area of forming surface <NUM> may be greater than a contact area between forming surface <NUM> and forming bladder <NUM> when forming bladder <NUM> presses ply <NUM> against forming surface <NUM>. This is illustrated in dashed lines in <FIG>, where an extent <NUM> of forming surface <NUM> is such that forming bladder <NUM> will not contact an entirety of forming surface <NUM> when forming bladder <NUM> operatively presses ply <NUM> against forming surface <NUM>. It is within the scope of the present discourse that extent <NUM> may include and/or be any suitable dimension of forming surface <NUM>, such as a length <NUM>, or longitudinal length <NUM>, and/or a width <NUM> of forming surface <NUM>. As an example, <FIG> illustrate that length <NUM> of forming surface <NUM> may be greater than a corresponding length of forming machine <NUM> and/or of forming bladder <NUM> thereof.

The contact between forming surface <NUM> and forming bladder <NUM> is discussed in more detail herein with reference to process flow <NUM> of <FIG>. As used herein, the word "contact" may include direct and/or indirect contact. As an example, and with reference to <FIG>, ply <NUM> may extend between forming bladder <NUM> and forming surface <NUM>. Thus, forming bladder <NUM> may directly contact ply <NUM> and/or may indirectly contact forming surface <NUM> when pressing ply <NUM> against forming surface <NUM>. However, and as illustrated in dashed lines in <FIG>, an intermediate film <NUM> may extend between forming bladder <NUM> and ply <NUM>. Under these conditions, forming bladder <NUM> may directly contact intermediate film <NUM> and may indirectly contact both ply <NUM> and forming surface <NUM>. Examples of intermediate film <NUM> include a contact film, a release film, a fluoropolymer film, and/or a film that is approved for contact with ply <NUM>.

With continued reference to <FIG>, and when length <NUM> of forming surface <NUM> is greater than a corresponding length <NUM> of forming bladder <NUM>, positioning device <NUM> may be configured to selectively move forming bladder <NUM> along length <NUM>. Additionally or alternatively, and when width <NUM> of forming surface <NUM> is greater than a corresponding width <NUM> of forming bladder <NUM>, positioning device <NUM> may be configured to selectively move forming bladder <NUM> across width <NUM>.

It is within the scope of the present disclosure that forming surface <NUM> may have and/or define any suitable shape. As an example, forming surface <NUM> may be a planar, or at least substantially planar, forming surface <NUM>. As another example, forming surface <NUM> may be arcuate in at least one dimension, as illustrated in <FIG>.

Forming bladder <NUM> may include any suitable structure that may define and/or surround internal volume <NUM> and/or that may operatively press ply <NUM> against forming surface <NUM> while forming bladder <NUM> is inflated to the forming pressure. As an example, forming bladder <NUM> may include an elastomeric body that defines internal volume <NUM>. As additional examples, forming bladder <NUM> may include and/or be a fluid bladder, an air bladder, and/or a resilient forming bladder.

It is within the scope of the present disclosure that, subsequent to inflation of forming bladder <NUM>, such as to the forming pressure, forming bladder <NUM> may be shaped, designed, and/or configured to operatively press a central region of a pressed portion of ply <NUM> against forming surface <NUM> prior to operatively pressing a peripheral region of the pressed portion against forming surface <NUM>. This is discussed in more detail herein with reference to process flow <NUM> of <FIG>.

As illustrated in <FIG>, forming surface <NUM> may be configured to receive a plurality of stacked plies <NUM> of composite material. Under these conditions, the plurality of stacked plies <NUM> may be layered, one on top of the other, to form and/or define composite part <NUM>. When forming surface <NUM> receives the plurality of stacked plies <NUM>, it is within the scope of the present disclosure that forming bladder <NUM> may be configured to operatively press each of the plurality of stacked plies <NUM> against forming surface <NUM>. This may include concurrently pressing at least two, or even the plurality of, stacked plies <NUM> of composite material against forming surface <NUM> and/or sequentially pressing at least two different, or even each of the plurality of, stacked plies <NUM> of composite material against forming surface <NUM>.

Pressure-regulating device <NUM> may include any suitable structure that may be adapted, configured, designed, and/or constructed to regulate the pressure within internal volume <NUM>, to inflate forming bladder <NUM>, and/or to maintain the pressure within internal volume <NUM> at, or near, the forming pressure prior to, during, and/or subsequent to forming a given ply <NUM> against forming surface <NUM>. This may include supplying fluid to internal volume <NUM> and/or permitting fluid to flow from internal volume <NUM> responsive to changes in internal volume <NUM> and/or responsive to shroud <NUM> acting against internal forming bladder <NUM>. As an example, pressure-regulating device <NUM> may include and/or be a pressurizing fluid supply that is configured to selectively inflate forming bladder <NUM> to the forming pressure.

It is within the scope of the present disclosure that pressure-regulating device <NUM> further may be configured to maintain the pressure within internal volume <NUM> to within a threshold pressure differential of the forming pressure while forming bladder <NUM> operatively presses ply <NUM> against forming surface <NUM>. Examples of the threshold pressure differential include threshold pressure differentials of less than <NUM> kilopascals (kPa), less than <NUM> kPa, less than <NUM> kPa, less than <NUM> kPa, less than <NUM> kPa, less than <NUM> kPa, less than <NUM> kPa, or less than <NUM> kPa.

As an example, pressure-regulating device <NUM> may be configured to permit fluid to exit forming bladder <NUM> while forming bladder <NUM> operatively presses ply <NUM> against forming surface <NUM>. As more specific examples, pressure-regulating device <NUM> may not include and/or be a positive displacement device pressure-regulating device and/or may be configured to generate and maintain a given pressure differential thereacross, with this given pressure differential corresponding to the forming pressure and/or to the compaction pressure. As additional, more specific examples, pressure-regulating device <NUM> may include and/or be a fan, a blower, a cyclone, a tornado, a venturi pump, and/or a pressure relief valve.

It is within the scope of the present disclosure that pressure-regulating device <NUM> further may be configured to selectively inflate forming bladder <NUM> to a compaction pressure that is greater than the forming pressure. Under these conditions, and subsequent to forming bladder <NUM> being utilized to operatively press ply <NUM> against forming surface <NUM>, as illustrated in dash-dot lines in <FIG>, the pressure within internal volume <NUM> may be increased to the compaction pressure to compact ply <NUM> against forming surface <NUM>.

Positioning device <NUM> may include and/or be any suitable structure that may be adapted, configured, designed, and/or constructed to selectively position forming bladder <NUM> relative to forming surface <NUM> at the plurality of selected locations. As examples, forming device <NUM> may include an automated positioning device, a motorized positioning device, and/or a manually actuated positioning device. As a more specific example, and as illustrated in <FIG>, positioning device <NUM> may include and/or be a linear guide <NUM> and/or a linear actuator <NUM>. As illustrated in dashed lines in <FIG>, positioning device <NUM> further may include a locking mechanism <NUM> that is configured to selectively and operatively retain positioning device <NUM> at a selected one, or even each, of the plurality of selected locations.

It is within the scope of the present disclosure that positioning device <NUM> may be configured to operatively translate forming machine <NUM> and/or forming bladder <NUM> thereof in any suitable direction, along any suitable axis, and/or within any suitable plane. As an example, positioning device <NUM> may be configured to operatively translate forming machine <NUM> and/or forming bladder <NUM> horizontally, or at least substantially horizontally, in a horizontal plane, or within an at least substantially horizontal plane, along a length of forming mandrel <NUM>, and/or across a width of forming mandrel <NUM>.

It is within the scope of the present disclosure that system <NUM> may be configured such that forming bladder <NUM> selectively and operatively presses ply <NUM> against forming surface <NUM> responsive to being inflated to the forming pressure. Alternatively, and as illustrated in dashed lines in <FIG> and in solid lines in <FIG>, system <NUM> further may include an engagement structure <NUM>, or even a plurality of engagement structures <NUM>, that may be adapted, configured, designed, and/or constructed to selectively and operatively engage forming bladder <NUM> with ply <NUM> and/or with forming surface <NUM>. This may include selectively and operatively engaging forming bladder <NUM> with ply <NUM> and/or with forming surface <NUM> subsequent to inflation of forming bladder <NUM> to the forming pressure.

As an example, engagement structure <NUM> may be configured to operatively translate forming bladder <NUM> relative to forming surface <NUM>. This may include operative translation of forming bladder <NUM> toward forming surface <NUM>, operative translation of forming bladder <NUM> away from forming surface <NUM>, operative translation of forming bladder <NUM> vertically, operative translation of forming bladder <NUM> at least substantially vertically, operative translation of forming bladder <NUM> in a vertical direction, and/or operative translation of forming bladder <NUM> in an at least substantially vertical direction. Additionally or alternatively, this also may include selectively varying a distance, or a vertical distance, between forming surface <NUM> and forming bladder <NUM>.

It is within the scope of the present disclosure that engagement structure <NUM>, when present, may include and/or be any suitable structure. As examples, engagement structure <NUM> may be separate and/or distinct from positioning device <NUM>, may form a portion of positioning device <NUM>, and/or may be operatively interlinked with positioning device <NUM>, such as via a support structure <NUM>, which also may be referred to herein as a support tower <NUM>. As additional examples, engagement structure <NUM> may include and/or be an automated engagement structure <NUM>, a motorized engagement structure <NUM>, and/or a manually actuated engagement structure <NUM>. As a more specific example, engagement structure <NUM> may include and/or be a screw jack <NUM>, a linear actuator, a motor, an electric motor, and/or a pneumatic motor.

It is within the scope of the present disclosure that engagement structure <NUM> may include and/or be a pivoting engagement structure <NUM> that is configured to permit forming bladder <NUM> and/or shroud <NUM> to pivot relative to forming surface <NUM> about a pivot axis <NUM>, as illustrated in <FIG>. Pivot axis <NUM> may be defined by a pivot structure <NUM> that may form a portion of engagement structure <NUM> and/or that may operatively interlink engagement structure <NUM> to forming bladder <NUM>. Such a configuration may improve operative contact between forming bladder <NUM> and ply <NUM> when forming bladder <NUM> operatively presses ply <NUM> against forming surface <NUM>, especially when forming surface <NUM> is nonplanar, arcuate, contoured, and/or complex. Examples of pivot structure <NUM> include a knuckle joint, a u-joint, and/or a constant velocity joint.

It is within the scope of the present disclosure that pivot axis <NUM> may extend in any suitable direction. As an example, pivot axis <NUM> may extend along, be parallel to, and/or be aligned with a longitudinal axis of forming surface <NUM> and/or of forming die <NUM> (i.e., may extend along a length of forming surface <NUM> and/or of forming die <NUM>). Additionally or alternatively, pivot axis <NUM> may extend along, be parallel to, and/or be aligned with a transverse axis of forming surface <NUM> and/or of forming die <NUM> (i.e., may extend perpendicular, or at least substantially perpendicular, to the length of forming surface <NUM> and/or of forming die <NUM>).

As discussed in more detail herein, system <NUM> and/or engagement structure <NUM> thereof may be adapted, configured, designed, constructed, and/or programmed to selectively regulate and/or control a rate at which forming bladder <NUM> operatively presses ply <NUM> against forming surface <NUM>. Such regulation and/or control may regulate and/or control the pressure within internal volume <NUM> and/or may permit system <NUM> to maintain the pressure within internal volume <NUM> to within the threshold pressure differential of the forming pressure while ply <NUM> is conformed to forming surface <NUM> by forming machine <NUM>.

As illustrated in dashed lines in <FIG> and in solid lines in <FIG>, system <NUM> and/or forming machine <NUM> thereof further may include a shroud <NUM>. Shroud <NUM> may be adapted, configured, designed, constructed, and/or shaped to surround at least a portion of forming bladder <NUM>. As examples, shroud <NUM> may surround and/or extend at least partially around at least <NUM>, at least <NUM>, or at least <NUM> sides of forming bladder <NUM>. As illustrated, shroud <NUM> may have and/or define a U-shaped, or at least substantially U-shaped transverse cross-sectional shape; however, this is not required. As discussed in more detail herein with reference to process flow <NUM> of <FIG>, shroud <NUM> may be configured to press forming bladder <NUM> against both a horizontal portion of forming surface <NUM> and also against a vertical portion of forming surface <NUM>.

Shroud <NUM> may be formed from any suitable material, or materials, and/or may have any suitable property, or properties. As an example, shroud <NUM> may include and/or be a rigid, or at least substantially rigid, shroud <NUM>.

As illustrated in dashed lines in <FIG>, system <NUM> further may include a controller <NUM>. Controller <NUM> may be adapted, configured, and/or programmed to control the operation of at least a portion of system <NUM>. As examples, controller <NUM> may control the operation of pressure-regulating device <NUM>, positioning device <NUM>, and/or engagement structure <NUM>, when present. This may include controlling system <NUM> to perform any suitable portion of methods <NUM>, which are discussed in more detail herein with reference to <FIG>.

As an example, controller <NUM> may be programmed to regulate a rate at which forming bladder <NUM> presses ply <NUM> against forming surface <NUM>, such as to regulate a pressure within internal volume <NUM>. As another example, controller <NUM> may be programmed to control the operation of pressure-regulating device <NUM> to regulate the pressure within internal volume <NUM>. As yet another example, and subsequent to ply <NUM> being operatively pressed against forming surface <NUM>, controller <NUM> may be programmed to increase the pressure within internal volume <NUM> to the compaction pressure and/or to compact ply <NUM> against forming surface <NUM>.

It is within the scope of the present disclosure that system <NUM> and/or forming machine <NUM> thereof further may include a pressure detector <NUM>. Pressure detector <NUM> may be configured to monitor the pressure within internal volume <NUM> and/or to convey a pressure signal <NUM>, which may be indicative of the pressure within internal volume <NUM>, to controller <NUM>. Under these conditions, controller <NUM> may be programmed to control the operation of system <NUM> based, at least in part, on pressure signal <NUM>. Additionally or alternatively, pressure detector <NUM> may include and/or be a pressure gauge <NUM> and/or a mechanical pressure gauge <NUM> that may not, necessarily, generate and/or convey pressure signal <NUM>.

It is also within the scope of the present disclosure that system <NUM> and/or forming machine <NUM> thereof may include a proximity indicator <NUM>. Proximity indicator <NUM>, when present, may be configured to monitor and/or detect a distance between at least a portion of forming machine <NUM> and forming surface <NUM> and/or to monitor and/or detect when the portion of forming machine <NUM> is within a threshold distance of forming surface <NUM>. In addition, proximity indicator <NUM> also may be configured to convey a proximity signal <NUM> to controller <NUM>. Proximity signal <NUM> may be indicative of the distance between the portion of forming machine <NUM> and forming surface <NUM> and/or may be indicative of whether or not the portion of forming machine <NUM> is within the threshold distance of forming surface <NUM>. Examples of the portion of forming machine <NUM> include forming bladder <NUM> and/or shroud <NUM>. Examples of proximity indicator <NUM> include a distance sensor, a force sensor, and/or a pressure sensor.

Composite part <NUM> may include and/or be any suitable composite part <NUM> that may be formed from the plurality of plies <NUM> of composite material. Examples of composite part <NUM> include a stringer for an aircraft, a spar for an aircraft, and/or an angular composite part for an aircraft. However, system <NUM> may be utilized to form composite parts <NUM> that are not designed to form a portion of an aircraft.

It is within the scope of the present disclosure that plies <NUM> within composite part <NUM> may be single, continuous plies <NUM> that may extend across an entirety of forming surface <NUM>. Additionally or alternatively, it is also within the scope of the present disclosure that one or more ply <NUM> may be formed from a plurality of ply segments <NUM> that together extend across the entirety of forming surface <NUM>. Stated another way, a given layer, or ply <NUM>, within composite part <NUM> may be formed from a single, continuous sheet of composite material and/or may be formed from a plurality of segments, sections, or pieces of composite material, with these segments, sections, and/or pieces of composite material being referred to herein as ply segments <NUM> and abutting one another to form and/or define the given layer.

Plies <NUM> of composite material may include any suitable structure and/or structures. As examples, plies <NUM> may include a plurality of fibers, such as a plurality of carbon, polymeric, and/or glass fibers. As additional examples, plies <NUM> may include a resin material, such as an epoxy, an adhesive, and/or a polymeric resin. As further examples, plies <NUM> may include a pre-impregnated, or pre-preg, material that includes the plurality of fibers and the resin material.

As illustrated in dashed lines in <FIG>, system <NUM> further may include an indexing structure <NUM>. Indexing structure <NUM>, when present, may be configured to operatively locate each ply segment <NUM> at a desired, target, or specified location on forming surface <NUM>. Examples of indexing structure <NUM> include physical indexing structures <NUM>, such as an indexing fence, and/or optical indexing structures <NUM>, such as an optical layout template.

<FIG> are schematic top views of a process flow <NUM> for incrementally forming composite part <NUM> utilizing the systems and methods according to the present disclosure, while <FIG> are schematic cross-sectional views of process flow <NUM>. As illustrated in <FIG>, forming machine <NUM> initially may be located at a first selected location along the length of a forming mandrel <NUM> and may operatively press a first portion of a ply <NUM> of composite material against a forming surface <NUM> that is defined by forming mandrel <NUM>.

An example of the process that may be utilized to operatively press ply <NUM> against forming surface <NUM> is illustrated in <FIG>. As illustrated in <FIG>, forming machine <NUM> may include a forming bladder <NUM> that initially may operatively press a central region <NUM> of ply <NUM> against forming surface <NUM> prior to operatively pressing a peripheral region <NUM> against forming surface <NUM>.

Subsequently, and as illustrated in <FIG>, forming bladder <NUM> may operatively contact an entirety, or at least substantially the entirety, of an exposed, upper, or bladder-facing surface <NUM> of ply <NUM> may press ply <NUM> toward, against, and/or into contact with forming surface <NUM>. This may include directing ply <NUM> to bend around one or more surface contours of forming surface <NUM> and/or pressing ply <NUM> into contact with both horizontal and vertical portions of forming surface <NUM>, as illustrated. As illustrated in <FIG>, forming bladder <NUM> may be pressed even further over forming mandrel <NUM>, thereby pressing an entirety of ply <NUM> against forming surface <NUM>, and a shroud <NUM> may constrain forming bladder <NUM> such that forming bladder <NUM> presses the entirety of ply <NUM> against forming surface <NUM>. Subsequently, and as discussed, a pressure within an internal volume <NUM> of forming bladder <NUM> may be increased to compact ply <NUM> against forming surface <NUM>.

Returning to <FIG>, and as illustrated in <FIG>, forming machine <NUM> may be progressively moved along and/or across forming surface <NUM> to operatively press ply <NUM> against forming surface <NUM> at each of the plurality of selected locations, thereby conforming an entirety of ply <NUM> to forming surface <NUM>. In the example of <FIG>, a given ply <NUM> is formed from a plurality of ply segments <NUM>; however, this is not required. As an example, and as illustrated in <FIG>, a single, continuous sheet of composite material may form and/or define a given ply <NUM>. Additionally or alternatively, <FIG> illustrates that, when a given ply <NUM> includes the plurality of ply segments <NUM>, ply segments <NUM> may be arranged with any suitable relative orientation and/or may have any suitable size.

Process flow <NUM> may be repeated any suitable number of times to locate and/or build-up any suitable number of plies <NUM> of composite material on forming surface <NUM> of forming mandrel <NUM> and to thereby form and/or define composite part <NUM>. This is illustrated in <FIG>, which is a schematic cross-sectional view of a composite part <NUM> that has been formed on a forming mandrel <NUM> utilizing the systems and methods according to the present disclosure. As illustrated, composite part <NUM> includes a plurality of stacked and/or layered plies <NUM> of composite material that may be located and/or built-up on forming surface <NUM> in a sequential manner, as discussed.

<FIG> is flowchart depicting methods <NUM>, according to the present disclosure, of incrementally forming a composite part. Methods <NUM> include placing a ply of composite material at <NUM> and may include inflating an internal volume of a forming bladder at <NUM>. Methods <NUM> further include pressing the forming bladder against the ply of composite material at <NUM> and may include maintaining a pressure at <NUM>, constraining the forming bladder at <NUM>, compacting the ply of composite material at <NUM>, separating the forming bladder from the ply of composite material at <NUM>, and/or moving the forming bladder at <NUM>. Methods <NUM> further include repeating at least a portion of the methods at <NUM> and may include curing the composite structure at <NUM>.

Placing the ply of composite material at <NUM> may include placing the ply of composite material on a forming surface of a forming mandrel. Examples of the forming surface, of the forming mandrel, and of the ply of composite material are disclosed herein. It is within the scope of the present disclosure that the placing at <NUM> may include bringing at least a portion of the ply of composite material into direct and/or indirect contact with the forming surface such that the ply of composite material is at least partially supported by the forming surface.

It is also within the scope of the present disclosure that the placing at <NUM> may include utilizing an indexing structure to aid in the placing and/or to operatively locate the ply of composite material at a desired, target, or specified location on the forming surface. Examples of the indexing structure are disclosed herein.

As discussed in more detail herein, the placing at <NUM> may include, or consist of, placing a single, continuous ply of composite material that extends across an entirety of the forming surface. Under these conditions, the pressing at <NUM> may include pressing a selected portion of the single, continuous ply of composite material against the forming surface while a remainder of the ply of composite material is not pressed against the forming surface. Additionally or alternatively, the placing at <NUM> also may include placing at least two discrete and/or separate ply segments that together define the ply of composite material. Under these conditions, the pressing at <NUM> may include pressing either an entirety of a given ply segment or less than the entirety of the given ply segment against the forming surface.

Inflating the internal volume of the forming bladder at <NUM> may include inflating the internal volume to a forming pressure. This may include inflating in any suitable manner and/or utilizing any suitable pressure-regulating device, examples of which are disclosed herein. It is within the scope of the present disclosure that the inflating at <NUM> may be performed prior to the pressing at <NUM> and/or that the pressing at <NUM> may be a result of, or responsive to, the inflating at <NUM>.

Pressing the forming bladder against the ply of composite material at <NUM> may include pressing at a selected location to press a selected portion of the ply of composite material against the forming surface and/or to conform the selected portion of the ply of composite material to a surface profile of the forming surface. The pressing at <NUM> may be accomplished in any suitable manner. As an example, the pressing at <NUM> may be a result of, or may be responsive to, the inflating at <NUM>, as discussed. As another example, the pressing at <NUM> may include lowering the forming bladder into contact with the selected portion of the ply of composite material and/or moving the forming bladder in a vertical direction, such as via utilizing an engagement structure, to deform the selected portion of the ply of composite material between the forming bladder and the forming surface and/or to conform the selected portion of the ply of composite material to the surface profile of the forming surface.

In general, the systems and methods disclosed herein utilize incremental forming to conform the ply of composite material to the forming surface and/or to form the composite part. As such, and as discussed herein with reference to process flow <NUM> of <FIG>, the forming surface and the ply of composite material generally are larger than the forming bladder. Thus, the repeating at <NUM> is utilized to form an entirety of a given ply of composite material.

As an example, a surface area of the forming surface may be greater than a contact area between the forming surface and the forming bladder during the pressing at <NUM>. As another example, a surface area, an exposed surface area, and/or an upper surface area of the ply of composite material may be greater than a surface area, an exposed surface area, and/or an upper surface area of the selected portion of the ply of composite material and/or may be greater than the contact area between the forming surface and the forming bladder during the pressing at <NUM>.

The pressing at <NUM> further may include conforming the forming bladder to the forming surface such that a surface profile of the forming bladder corresponds to the surface profile of the forming surface. As discussed herein, the pressing at <NUM> may include operatively contacting the forming bladder with a central, or upper, region of the selected portion of the ply of composite material prior to operatively contacting the forming bladder with a peripheral, or side, region of the selected portion of the ply of composite material. Such a method may retain the ply of composite material on the forming surface during the pressing at <NUM> and/or may decrease a potential for wrinkling of the ply of composite material during the pressing at <NUM>.

As discussed herein, the ply of composite material may include and/or be defined by a plurality of ply segments. Under these conditions, the pressing at <NUM> may include pressing a given ply segment of the plurality of ply segments. A surface area, an exposed surface area, or an upper surface area of the given ply segment may be less than the contact area between the forming surface and the forming bladder during the pressing at <NUM>. Thus, the pressing at <NUM> may include pressing an entirety of the given ply segment at one time. Additionally or alternatively, the surface area, the exposed surface area, and/or the upper surface area of the given ply segment may be greater than the contact area between the forming surface and the forming bladder during the pressing at <NUM>. Thus, the repeating at <NUM> may include repeating to press the entirety of the given ply segment.

As also discussed herein, a proximity indicator may be utilized to monitor and/or detect a distance between at least a portion of the forming machine and the forming surface and/or to monitor and/or detect when the portion of the forming machine is within a threshold distance of the forming surface. Under these conditions, the methods <NUM> further may include ceasing the pressing at <NUM> responsive to the proximity indicator detecting that the portion of the forming machine is within the threshold distance of the forming surface.

Maintaining the pressure at <NUM> may include maintaining the pressure within the internal volume during the pressing at <NUM>. This may include maintaining the pressure at, or near, the forming pressure and/or maintaining the pressure to within a threshold pressure differential of the forming pressure. Additionally or alternatively, the maintaining at <NUM> also may include maintaining with, or utilizing, a pressure-regulating device. Examples of the threshold pressure differential and the pressure-regulating device are disclosed herein.

The maintaining at <NUM> may include permitting fluid, such as air, to exit the forming bladder during the pressing at <NUM>. This may include permitting the fluid to exit through, or via, the pressure-regulating device. Additionally or alternatively, the maintaining at <NUM> also may include regulating a rate at which the forming bladder presses the ply of composite material against the forming surface, such as during the pressing at <NUM>.

As discussed, a pressure detector may be utilized to monitor the pressure within the internal volume of the forming bladder. Under these conditions, methods <NUM> further may include measuring the pressure within the internal volume with the pressure detector and the maintaining at <NUM> may include maintaining based, at least in part, on the measured pressure.

Constraining the forming bladder at <NUM> may include constraining deformation and/or expansion of the forming bladder in at least one direction. As an example, the constraining at <NUM> may include constraining with a shroud, examples of which are disclosed herein. It is within the scope of the present disclosure that the constraining at <NUM> may include constraining to permit the forming bladder to press the ply of composite material against the forming surface across an entirety of the surface profile of the forming surface and/or across an entirety of the ply of composite material. The constraining at <NUM> may include restricting expansion, motion, and/or deformation of the forming bladder on one, two, three, or more than three sides of the forming bladder.

Compacting the ply of composite material at <NUM> may include compacting the ply of composite material against the forming surface and may be accomplished in any suitable manner. As an example, the compacting at <NUM> may include increasing the pressure within the internal volume of the forming bladder to a compaction pressure, which may be greater than the forming pressure. Under these conditions, the pressure may be increased subsequent to the pressing at <NUM> and/or subsequent to completion of the pressing at <NUM>. As an additional example, the compacting at <NUM> may include vacuum compacting the ply of composite material, such as via covering the ply of composite material with a vacuum bag and evacuating a space between the ply of composite material and the vacuum bag.

Separating the forming bladder from the ply of composite material at <NUM> may include establishing a spaced-apart relationship between the forming bladder and the ply of composite material and may be performed subsequent to the placing at <NUM>, subsequent to the inflating at <NUM>, and/or subsequent to the pressing at <NUM>. The separating at <NUM> may include separating at each of the plurality of selected locations, separating to permit and/or facilitate the moving at <NUM>, and/or separating to permit and/or facilitate the repeating at <NUM>. The separating at <NUM> may be performed in any suitable manner. As examples, the separating at <NUM> may include translating the forming bladder in a vertical direction and/or translating the forming bladder with the engagement structure.

Moving the forming bladder at <NUM> may include moving the forming bladder to each location in the plurality of selected locations prior to pressing the forming bladder against the ply of composite material at each location. The moving at <NUM> may be accomplished in any suitable manner. As an example, the moving at <NUM> may include translating the forming bladder along a length of the forming mandrel, translating the forming bladder across a width of the forming mandrel, translating the forming bladder horizontally, and/or translating the forming bladder with a positioning device, examples of which are disclosed herein.

Repeating at least the portion of the methods at <NUM> may include repeating a plurality of times and/or at the plurality of selected locations to selectively and operatively press the ply of composite material against the forming surface at each of the plurality of selected locations. This may include conforming corresponding portions of the ply of composite material to the surface profile of the forming surface to at least partially define the composite part.

As discussed, the ply of composite material may be defined by the plurality of discrete ply segments. Under these conditions, the repeating at <NUM> also may include repeating the placing at <NUM> for each discrete ply segment in the plurality of discrete ply segments and subsequently repeating the pressing at <NUM> to press the forming bladder against each ply segment. This process may define the ply of composite material and/or may conform the ply of composite material to the surface profile of the forming surface.

Additionally or alternatively, and as also discussed, the ply of composite material may consist of a single, continuous ply of composite material. Under these conditions, the repeating at <NUM> may include repeating the pressing at <NUM> a plurality of times and/or at a plurality of different locations on the single, continuous ply of composite material.

As discussed, the ply of composite material may be a first ply of composite material, and the composite part may include a plurality of plies of composite material that may be stacked, one on top of the other, to define a layered stack of composite material. Under these conditions, the repeating at <NUM> additionally or alternatively may include placing a second ply of composite material on the first ply of composite material and subsequently pressing the forming bladder against the second ply of composite material to form the layered stack of composite material.

Curing the composite structure at <NUM> may include curing to generate, form, harden, consolidate, and/or define the composite part and may be accomplished in any suitable manner and/or with any suitable timing and/or sequence during methods <NUM>. As an example, the curing at <NUM> may be performed subsequent to the repeating at <NUM>. As another example, the curing at <NUM> may include heating the ply of composite material and/or the plurality of stacked plies of composite material.

Referring now to <FIG>, embodiments of the disclosure may be described in the context of an aircraft manufacturing and service method <NUM>, as shown in <FIG>, and/or an aircraft <NUM>, as shown in <FIG>. During pre-production, exemplary method <NUM> may include specification and design <NUM> of the aircraft <NUM> and material procurement <NUM>. During production, component and subassembly manufacturing <NUM> and system integration <NUM> of the aircraft <NUM> take 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 also may include modification, reconfiguration, refurbishment, and so on).

For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.

As shown in <FIG>, 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 invention may be applied to other industries, such as the automotive industry.

Systems and methods embodied herein may be employed during any one or more of the stages of the manufacturing and service method <NUM>. For example, components or subassemblies corresponding to component and subassembly manufacturing process <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 of system 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 system 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>.

Claim 1:
A system (<NUM>) for incrementally forming a composite part (<NUM>), the system (<NUM>) comprising:
a forming mandrel (<NUM>) that includes a forming surface (<NUM>), wherein a surface profile of the forming surface (<NUM>) corresponds to a surface profile of the composite part (<NUM>), and further wherein the forming surface (<NUM>) is configured to receive a ply (<NUM>) of composite material; and
a forming machine (<NUM>) including:
(i) a forming bladder (<NUM>) that defines an internal volume (<NUM>);
(ii) a pressure-regulating device (<NUM>) configured to regulate a pressure within the internal volume (<NUM>); and
(iii) a positioning device (<NUM>) configured to selectively position the forming bladder (<NUM>) relative to the forming surface (<NUM>) at a plurality of selected locations;
wherein the forming bladder (<NUM>) is configured to be inflated to a forming pressure and to selectively and operatively press the ply (<NUM>) of composite material against the forming surface (<NUM>) at each of the plurality of selected locations to conform corresponding portions of the ply (<NUM>) of composite material to the surface profile of the forming surface (<NUM>) and at least partially define the composite part (<NUM>);
wherein the positioning device (<NUM>) is configured to operatively translate the forming bladder (<NUM>) relative to the forming mandrel (<NUM>) along a length of the forming mandrel (<NUM>);
wherein the forming machine (<NUM>) further includes a controller programmed to control the operation of at least one of the pressure-regulating device (<NUM>) and/or the positioning device (<NUM>);
wherein the forming surface (<NUM>) is configured to receive a plurality of stacked plies of composite material to define the composite part (<NUM>); and
wherein the forming bladder (<NUM>) is configured to sequentially press each of the plurality of stacked plies of composite material against the forming surface (<NUM>).