Patent Publication Number: US-2016236425-A1

Title: Roughened tool surfaces for thermoset composite layups and systems and methods including the same

Description:
FIELD 
     The present disclosure relates to roughened tool surfaces for thermoset composite layups, to systems that include the roughened tool surface, and/or to methods that utilize the roughened tool surfaces. 
     BACKGROUND 
     Tool surfaces, such as layup mandrel surfaces, often may be utilized to support thermoset composite layups during formation thereof. These thermoset composite layups generally include a plurality of layers of pre-impregnated (pre-preg) material that are progressively built up on the tool surface. Generally, the plurality of layers of pre-preg is compacted on the tool surface to remove void space between individual layers, to bring adjacent layers into contact with one another, to conform the thermoset composite layup to a shape of the tool surface, and/or to adhere the adjacent layers to one another. Subsequently, the thermoset composite layup may be heated, while still being supported by the tool surface, to cure the thermoset composite layup. The cured thermoset composite layup then may be removed from the tool surface to produce a cured composite part, which may be in final form and/or may receive additional processing prior to producing a final composite part. 
     Under certain circumstances, it may be desirable to remove the thermoset composite layup from the tool surface prior to curing the thermoset composite layup. However, this removal may be difficult without damaging the thermoset composite layup. As an example, adhesive forces between the thermoset composite layup and the tool surface may cause deformation of the thermoset composite layup during removal from the tool surface, and this deformation may produce undesirable buckling, wrinkling, layer-layer shifting, and/or other distortion of the thermoset composite layup. Thus, there exists a need for roughened tool surfaces for thermoset composite layups and/or for systems and methods that include and/or utilize the roughened tool surfaces. 
     SUMMARY 
     Roughened tool surfaces for thermoset composite layups and systems and methods including the same are disclosed herein. The systems include a first tool that includes a first tool body that defines the roughened tool surface and a second tool that defines a second tool surface. The roughened tool surface is shaped to receive and to form a plurality of plies of thermoset composite material. The plurality of plies of thermoset composite material defines a thermoset composite layup. A roughness of the roughened tool surface is within a predefined roughness range. The second tool surface is configured to receive a plurality of discrete thermoset composite layups and to be heated with the plurality of discrete thermoset composite layups to cure the plurality of discrete thermoset composite layups and define a thermoset composite structure. The plurality of discrete thermoset composite layups includes the thermoset composite layup that is defined with, and has been removed from, the first tool. 
     The methods include methods of forming the thermoset composite structure. The methods include locating an initial layer of material on a roughened tool surface of a first tool. The roughened tool surface includes a plurality of perforations that is configured to provide fluid communication between the roughened tool surface and a fluid manifold. The method further includes applying a retention vacuum to the fluid manifold to retain the initial layer of material on the roughened tool surface and locating a plurality of plies of thermoset composite material on the initial layer of material to define a thermoset composite layup. The method also includes releasing the retention vacuum and removing the thermoset composite layup from the roughened tool surface of the first tool. The method further includes locating the thermoset composite layup on a second tool surface of a second tool and heating the second tool and the thermoset composite layup to cure the thermoset composite layup and define the thermoset composite structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an example of an aircraft that includes a thermoset composite structure that may be formed using the systems and methods according to the present disclosure. 
         FIG. 2  is an example of a fuselage barrel that may form a portion of the aircraft of  FIG. 1 . 
         FIG. 3  is a schematic view of a tool, according to the present disclosure, for receiving and forming a thermoset composite layup. 
         FIG. 4  is a schematic cross-sectional view of the tool of  FIG. 3 . 
         FIG. 5  is a schematic view of a system, according to the present disclosure, for forming a thermoset composite structure. 
         FIG. 6  is a flowchart depicting a method, according to the present disclosure, of forming a roughened tool surface on a tool body of a tool for receiving and forming a thermoset composite layup. 
         FIG. 7  is a flowchart depicting methods, according to the present disclosure, of forming a thermoset composite structure. 
         FIG. 8  is a flow diagram of aircraft production and service methodology. 
         FIG. 9  is a block diagram of an aircraft. 
     
    
    
     DESCRIPTION 
       FIGS. 1-9  provide examples of tools  100 , according to the present disclosure, for receiving and forming a thermoset composite structure  800 , of systems that may include and/or utilize tools  100 , of methods  200 , according to the present disclosure, of forming tools  100 , and/or of methods  300 , according to the present disclosure, of forming thermoset composite structures  800 . Elements that serve a similar, or at least substantially similar, purpose are labeled with like numbers in each of  FIGS. 1-9 , and these elements may not be discussed in detail herein with reference to each of  FIGS. 1-9 . Similarly, all elements may not be labeled in each of  FIGS. 1-9 , 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  FIGS. 1-9  may be included in and/or utilized with any of  FIGS. 1-9  without departing from the scope of the present disclosure. 
     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 without departing from the scope of the present disclosure. 
       FIG. 1  is an illustrative, non-exclusive example of an aircraft  700  that includes a thermoset composite structure  800 . Thermoset composite structure  800  may be constructed utilizing system  20 , tool  100 , and/or method  300 , according to the present disclosure.  FIG. 2  is an illustrative, non-exclusive example of a fuselage barrel  730  that may form a portion of aircraft  700  and includes thermoset composite structure  800 . Aircraft  700  and/or thermoset composite structure  800  thereof may include a plurality of skin segments  790  that may form, cover, and/or be an outer surface of any suitable portion of aircraft  700 . As illustrated most clearly in  FIG. 2 , aircraft  700  also may include a plurality of stringers  770  that, together with a plurality of frames  780 , may support an inner surface  792  of skin segments  790 . A plurality of fillers  760  may extend between frames  780  and inner surface  792  and may form a portion of thermoset composite structure  800 . Skin segments  790 , stringers  770 , frames  780 , and/or fillers  760  may be constructed utilizing system  20 , tool  100 , and/or method  300 , according to the present disclosure. 
     It is within the scope of the present disclosure that any suitable portion of aircraft  700  may be formed from and/or may be thermoset composite structure  800 . As illustrative, non-exclusive examples, thermoset composite structure  800  may form, or form a portion of, an airframe  710 , a fuselage  720 , a fuselage barrel  730 , a wing  740 , and/or a stabilizer  750  of aircraft  700 . 
       FIG. 3  is a schematic view of a tool  100 , according to the present disclosure, for receiving and forming a thermoset composite layup  30 , while  FIG. 4  is a schematic cross-sectional view of tool  100  of  FIG. 3 . Tool  100  includes a tool body  110  that includes, defines, and/or has at least one roughened tool surface  120 . Roughened tool surface  120  is adapted, configured, designed, sized, and/or shaped to receive and to form a plurality of plies  28  of thermoset composite material that may define a thermoset composite layup  30 . 
     Roughened tool surface  120  has a roughness that is within a predefined, preselected, and/or prescribed roughness range, and this roughness of roughened tool surface  120  may permit and/or facilitate utilization of tool  100 , location of plies  28  on roughened tool surface  120 , formation of thermoset composite layup  30  on roughened tool surface  120 , and/or subsequent removal of thermoset composite layup  30  from roughened tool surface  120 . As an example, and as illustrated, tool body  110  and/or roughened tool surface  120  thereof may include and/or define a plurality of perforations  130  that may be configured to provide fluid communication between roughened tool surface  120  and a fluid manifold  140  that is in fluid communication with the plurality of perforations. As illustrated in  FIGS. 3-4 , fluid manifold  140  may be at least partially, or even completely, defined by tool body  110 ; however, this is not required in all embodiments. 
     During formation of thermoset composite layup  30 , a retention vacuum may be applied to an interface  32  (as illustrated in  FIG. 4 ) between an initial layer  40  of material that extends across roughened tool surface  120 . Subsequently plies  28  may be located on initial layer  40  to form thermoset composite layup  30 . The retention vacuum may retain initial layer  40  on roughened tool surface  120  and/or resist motion of initial layer  40  during formation of thermoset composite layup  30 . Additionally or alternatively, and subsequent to formation of thermoset composite layup  30 , a fluid pressure may be applied to interface  32  via perforations  130  and fluid manifold  140 . This fluid pressure may generate a motive force for separation of initial layer  40  from roughened tool surface  120 , which may permit and/or facilitate removal of thermoset composite layup  30  from roughened tool surface  120 . 
     More conventional tools that may be utilized to form a conventional thermoset composite layup and that retain the conventional thermoset composite layup thereon during curing of the conventional thermoset composite layup to form a conventional thermoset composite structure generally include a smooth, or at least substantially smooth, tool surface. When compared to these conventional tools, the presence of roughened tool surface  120  on tools  100  according to the present disclosure may permit, facilitate, and/or improve fluid flow at interface  32 . 
     This improved fluid flow may increase a retention force that may retain initial layer  40  on roughened tool surface  120  during application of the retention vacuum, may decrease an occurrence of regions of interface  32  where the retention vacuum is not applied (or does not propagate from perforations  130 ), and/or may decrease an average spacing between perforations  130  that may be needed to produce a desired level of vacuum, or vacuum uniformity, at interface  32 . This also may aid in removal of thermoset composite layup from roughened tool surface  120  via the improved fluid flow to interface  32  during application of the fluid pressure, via a decrease in an actual area of contact between initial layer  40  and roughened tool surface  120 , and/or via a decrease in electrostatic forces that may serve to retain initial layer  40  in contact with roughened tool surface  120  subsequent to formation of thermoset composite layup  30 . 
     As discussed, tools  100  according to the present disclosure include tool body  110  that includes and/or defines roughened tool surface  120 . As also discussed, roughened tool surface  120  generally has a roughness that is within a predefined roughness range. This predefined roughness range may be based upon any suitable criteria. As examples, the predefined roughness range may be based, at least in part, on a modulus of elasticity of initial layer  40 , on a modulus of elasticity of plies  28 , and/or on a desired spacing between perforations  130 . 
     In general, a force needed to remove thermoset composite layup  30  from roughened tool surface  120  decreases with increasing roughness of roughened tool surface  120 . For very smooth surfaces and/or for roughened tool surfaces  120  that exhibit less than a threshold roughness, the force needed to remove thermoset composite layup  30  from roughened tool surface  120  may be (relatively) large. As the roughness of roughened tool surface  120  is increased, the force decreases substantially. However, a maximum practical value for the roughness may be selected based upon manufacturing specifications regarding a desired overall smoothness of thermoset composite layup  30  and/or of thermoset composite structure  800  that may be formed therefrom. 
     With this in mind, the predefined roughness range may extend between a minimum roughness and a maximum roughness (or the roughness may have a value that is defined between the minimum roughness and the maximum roughness). The minimum roughness and/or the maximum roughness may be selected, defined, and/or quantified based upon any suitable criteria. As an example, the minimum roughness and/or the maximum roughness may be quantified as an average peak-to-valley height, Rz, which may be defined by and/or measured utilizing ASME Y14.36M-1996. 
     As examples, the minimum roughness may have an average peak-to-valley height, Rz, of 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, 18 micrometers, 19 micrometers, or 20 micrometers. Additionally or alternatively, the maximum roughness may have an average peak-to-valley height, Rz, of 100 micrometers, 90 micrometers, 80 micrometers, 70 micrometers, 60 micrometers, 50 micrometers, 40 micrometers, 30 micrometers, 25 micrometers, 20 micrometers, 18 micrometers, 16 micrometers, 15 micrometers, 14 micrometers, 13 micrometers, 12 micrometers, 11 micrometers, or 10 micrometers. 
     Roughened tool surface  120  may be formed and/or defined in any suitable manner. In addition, roughened tool surface  120  may be roughened in a random manner and/or in a systematic manner. As an example, roughened tool surface  120  may be roughened such that a plurality of randomly located peaks and valleys extends thereacross. As another example, roughened tool surface  120  may be roughened such that a plurality of systematically and/or randomly located trenches, channels, and/or scratches extends thereacross. As yet another example, roughened tool surface  120  may include a plurality of roughened regions. The plurality of roughened regions may be proximal to and/or overlapping with one another. Additionally or alternatively, the roughened regions may be spaced apart from one another. As an example, each of the plurality of roughened regions may be proximal to and/or may surround a respective perforation  130 . 
     As a more specific example, roughened tool surface  120  may be formed by abrading tool body  110 . Under these conditions, roughened tool surface  120  also may be referred to herein as an abraded surface  120 . As another example, roughened tool surface  120  may be formed by grit blasting tool body  110 . Under these conditions, roughened tool surface  120  also may be referred to herein as a grit blasted surface  120 . As yet another example, roughened tool surface  120  may be formed by sanding tool body  110 . Under these conditions, roughened tool surface  120  also may be referred to herein as a sanded surface  120 . As another example, roughened tool surface  120  may be formed by knurling tool body  110 . Under these conditions, roughened tool surface  120  also may be referred to herein as a knurled surface  120 . As yet another example, roughened tool surface  120  may be formed by patterning tool body  110 . Under these conditions, roughened tool surface  120  also may be referred to herein as a patterned surface  120 . As another example, roughened tool surface  120  may be formed by lithographically patterning tool body  110 . Under these conditions, roughened tool surface  120  also may be referred to herein as a lithographically patterned surface  120 . As yet another example, roughened tool surface  120  may be formed by etching tool body  110 . Under these conditions, roughened tool surface  120  also may be referred to herein as an etched surface  120 . As another example, roughened tool surface  120  may be formed by chemically etching tool body  110 . Under these conditions, roughened tool surface  120  also may be referred to herein as a chemically etched surface  120 . As yet another example, roughened tool surface  120  may be formed by laser etching tool body  110 . Under these conditions, roughened tool surface  120  also may be referred to herein as a laser etched surface  120 . 
     Tool  100 , tool body  110 , and/or roughened tool surface  120  may include, have, and/or define any suitable shape. As an example, roughened tool surface  120  may include, or be, a planar, or at least substantially planar, roughened tool surface  120 . As another example, roughened tool surface  120  may define a surface contour (i.e., be non-linear) in two, or in only two, dimensions. As yet another example, roughened tool surface  120  may define a surface contour in three dimensions. As more specific examples, roughened tool surface  120  may have a shape that corresponds to and/or may be shaped to form thermoset composite layup  30  into one or more of a stringer of a composite aircraft, a skin of a composite aircraft, at least a portion of a wing of a composite aircraft, and/or at least a portion of a fuselage barrel of a composite aircraft. 
     Tool  100 , tool body  110 , and/or roughened tool surface  120  may include, have, and/or define any suitable size and/or extent. As an example, roughened tool surface  120  may define a maximum extent (or length) of at least 1 meter (m), at least 2 m, at least 3 m, at least 5 m, at least 10 m, at least 15 m, at least 20 m, at least 25 m, at least 30 m, at least 35 m, at least 40 m, at least 45 m, and/or at least 50 m. Additionally or alternatively, the maximum extent of roughened tool surface  120  may be less than 100 m, less than 90 m, less than 80 m, less than 70 m, less than 60 m, less than 50 m, less than 40 m, less than 30 m, less than 25 m, less than 20 m, less than 15 m, and/or less than 10 m. 
     As another example, roughened tool surface  120  may have a surface area of at least 0.5 square meters, at least 1 square meters, at least 2 square meters, at least 3 square meters, at least 4 square meters, at least 5 square meters, at least 6 square meters, at least 7 square meters, at least 8 square meters, at least 9 square meters, at least 10 square meters, at least 15 square meters, and/or at least 20 square meters. Additionally or alternatively, the surface area of roughened tool surface  120  may be less than 100 square meters, less than 90 square meters, less than 80 square meters, less than 70 square meters, less than 60 square meters, less than 50 square meters, less than 40 square meters, less than 30 square meters, less than 20 square meters, less than 10 square meters, and/or less than 5 square meters. 
     As discussed, tool  100 , tool body  110 , and/or roughened tool surface  120  may include and/or define the plurality of perforations  130 . Perforations  130  may define an average distance between a given one of the plurality of perforations  130  and a closest other of the plurality of perforations  130 . Examples of the average distance include average distances of at least 1 centimeter (cm), at least 2 cm, at least 3 cm, at least 4 cm, at least 5 cm, at least 6 cm, at least 7 cm, at least 8 cm, at least 9 cm, and/or at least 10 cm. Additionally or alternatively, the average distance also may be less than 20 cm, less than 18 cm, less than 16 cm, less than 14 cm, less than 12 cm, less than 10 cm, less than 9 cm, less than 8 cm, less than 7 cm, less than 6 cm, and/or less than 5 cm. 
     Tool  100  may include and/or be any suitable structure that may include tool body  110 , that may define roughened tool surface  120 , that may be configured to receive and/or support initial layer  40 , and/or that may be configured to receive and/or support the plurality of plies  28  of thermoset composite material that define thermoset composite layup  30 . As examples, tool  100  may include and/or be a layup mandrel, an inner mold line layup mandrel, and/or an outer mold line layup mandrel. 
       FIG. 5  is a schematic view of a system  20 , according to the present disclosure, for forming a thermoset composite structure  800 . System  20  includes a first tool  50  and a second tool  60 . First tool  50  includes, or is, tool  100  of  FIGS. 3-4 , and any of the structures, functions, and/or features of tool  100  of  FIGS. 3-4  may be included in and/or utilized with first tool  50  of  FIG. 5  without departing from the scope of the present disclosure. First tool  50  is configured to receive a plurality of plies  28  of thermoset composite material on a roughened tool surface  120  thereof such that the plurality of plies  28  of composite material defines a thermoset composite layup  30 . Second tool  60  defines a second tool surface  62  that is configured to receive a plurality of discrete thermoset composite layups  30 . In addition, second tool  60  is configured to be heated with the plurality of discrete thermoset composite layups  30  to cure the plurality of discrete thermoset composite layups  30  and to define thermoset composite structure  800 . 
     During operation of system  20 , an initial layer  40  of material may be located on roughened tool surface  120  of first tool  50 . In addition, a retention vacuum  72  may be applied, such as via a vacuum source  70 , to an interface  32  between initial layer  40  and roughened tool surface  120 . This may include application of the retention vacuum through and/or via one or more fluid manifolds  140  and/or perforations  130 , which are discussed in more detail herein with reference to  FIGS. 3-4 . 
     Subsequently, a plurality of plies  28  of thermoset composite material may be located on initial layer  40 , may be located on first tool  50 , and/or may be supported by roughened tool surface  120  of first tool  50  to define a thermoset composite layup  30 . During and/or subsequent to formation of thermoset composite layup  30 , plies  28  may be compacted onto roughened tool surface  120  utilizing a first compaction device  54 . 
     After formation thereof, thermoset composite layup  30  may be removed and/or separated from roughened tool surface  120  of first tool  50  prior to curing of thermoset composite layup  30 , and first tool  50  may be configured to permit and/or facilitate this separation. As an example, and as discussed, the presence of roughened tool surface  120  may decrease a force needed to separate thermoset composite layup  30  from roughened tool surface  120 . As another example, a fluid pressure  76  may be applied, such as via a fluid pressure source  74 , to interface  32 . This may include application of the fluid pressure through and/or via one or more fluid manifolds  140  and/or perforations  130 , as discussed in more detail herein with reference to  FIGS. 3-4 , and may provide a motive force for separation of initial layer  40  from roughened tool surface  120 . The separation may include separation of thermoset composite layup  30  from roughened tool surface  120  prior to receipt of thermoset composite layup  30  by second tool surface  62  of second tool  60 . 
     Subsequently, thermoset composite layup  30  may be located, placed, and/or received on second tool surface  62  of second tool  60 . In addition, and as illustrated, a plurality of discrete thermoset composite layups  30  also may be located, placed, and/or received on second tool surface  62 . The plurality of discrete thermoset composite layups  30  may be placed on second tool surface  62  while in an uncured state and/or prior to being cured. During and/or subsequent to the plurality of discrete thermoset composite layups  30  being received on second tool surface  62 , one or more of the plurality of discrete thermoset composite layups  30  may be compacted together and/or onto second tool surface  62 , such as via utilizing a second compaction device  64 . 
     After the plurality of discrete thermoset composite layups  30  has been located on second tool surface  62 , the plurality of discrete thermoset composite layups  30  may receive further processing. As an example, additional plies of composite material may be added to, supported by, and/or compacted on second tool surface  62 . As another example, the plurality of discrete thermoset composite layups  30  may be heated, such as via a heating assembly  90 . This may include heating on second tool surface  62  and/or on another tool surface that is different from second tool surface  62 . This heating may cure the plurality of discrete thermoset composite layups  30 , thereby forming thermoset composite structure  800 , which may be located on second tool surface  62 . Subsequently, thermoset composite structure  800  may be separated from second tool  60  and/or removed from second tool surface  62 , and second tool  60  may be configured to facilitate this separation. As an example, second tool  60  may include a plurality of sections  66  and/or portions  66  that may be separated from one another to facilitate separation of thermoset composite structure  800  therefrom. 
     First compaction device  54  and/or second compaction device  64  may include and/or be any suitable structure that may be adapted, configured, designed, and/or constructed to compact thermoset composite layup  30  on roughened tool surface  120  and/or to compact the plurality of discrete thermoset composite layups  30  on second tool surface  62 , respectively. Examples of first compaction device  54  and/or of second compaction device  64  include any suitable vacuum compaction device, vacuum bag, vacuum chuck, pneumatic compaction device, hydraulic compaction device, and/or mechanical compaction device. 
     As discussed, vacuum source  70  may be configured to apply retention vacuum  72  to roughened tool surface  120  and/or to interface  32  between roughened tool surface  120  and initial layer  40 . As an example, vacuum source  70  may be in selective fluid communication with perforations  130  via fluid manifold  140  (as illustrated in  FIGS. 2-3 ). Under these conditions, vacuum source  70  may be configured to selectively apply retention vacuum  72  to roughened tool surface  120  via the plurality of perforations  130 . 
     As also discussed, fluid pressure source  74  may be configured to apply fluid pressure  76  to roughened tool surface  120  and/or to interface  32  between roughened tool surface  120  and initial layer  40 . As an example, fluid pressure source  74  may be in selective fluid communication with perforations  130  via fluid manifold  140  (as illustrated in  FIG. 5 ). Under these conditions, fluid pressure source  74  may be configured to selectively apply fluid pressure  76  to roughened tool surface  120  via the plurality of perforations  130 . 
     Initial layer  40  may include and/or be any suitable layer of material that may be located on and/or placed into contact with roughened tool surface  120  during formation of thermoset composite layup  30 . As an example, initial layer  40  may include and/or be an initial ply  28  of thermoset composite material. As another example, initial layer  40  additionally or alternatively may include and/or be an intermediate layer that extends between the plurality of plies  28  and roughened tool surface  120 . Examples of the intermediate layer include a release film that is configured to facilitate separation of thermoset composite layup  30  from roughened tool surface  120 , an isolation film that is configured to prevent, or restrict, direct physical contact between thermoset composite layup  30  and roughened tool surface  120 , a low surface energy material, a fluorinated polymer film, a smooth intermediate layer, an at least substantially smooth intermediate layer, and/or a textured intermediate layer. 
     Heating assembly  90  may include and/or be any suitable structure that may be configured to heat second tool  60  and/or the plurality of discrete thermoset composite layups  30  that may be received on second tool surface  62  of second tool  60 . This may include heating second tool  60  and/or the plurality of discrete thermoset composite layups  30  to cure the plurality of discrete thermoset composite layups  30  and thereby form and/or define thermoset composite structure  800 . Examples of heating assembly  90  include an oven and/or a heat lamp. As illustrated in  FIG. 5 , heat source  90  may be configured to house and/or contain second tool  60  and the plurality of discrete thermoset composite layups  30  during heating thereof; however, this is not required. Heat source  90  may not be configured to heat (or may not heat) first tool  50 . 
     Generally, the plurality of discrete thermoset composite layups  30  includes thermoset composite layup  30  that was defined on first tool  50 , as well as one or more additional thermoset composite layups  30  that may be defined on first tool  50  and/or on a different tool. The different tool may be similar to tool  100  of  FIGS. 3-4 ; however, this is not required. Thus, and as illustrated, the plurality of discrete thermoset composite layups  30  may include and/or define a plurality of different shapes. As an example, and as illustrated in  FIG. 5 , the plurality of discrete thermoset composite layups  30  may define a plurality of stringers  770  and a plurality of skin segments  790 ; however, other shapes for the plurality of discrete thermoset composite layups are also within the scope of the present disclosure. 
     Thermoset composite layups  30  and/or plies  28  thereof may include and/or be formed from any suitable material and/or materials. As examples, plies  28  may include a fiberglass, a fiberglass cloth, a carbon fiber, a carbon fiber cloth, cloth, a pre-impregnated (pre-preg) composite material, a resin material, and/or an epoxy. 
       FIG. 6  is a flowchart depicting a method  200 , according to the present disclosure, of forming a roughened tool surface on a tool body of a tool for receiving and forming a thermoset composite layup. Methods  200  include receiving the tool body at  210  and roughening the tool body at  220 . 
     Receiving the tool body at  210  may include obtaining and/or procuring the tool body in any suitable manner. As examples, the receiving at  210  may include purchasing the tool body, fabricating the tool body, machining the tool body, obtaining the tool body, and/or locating the tool body in a work area where the roughening at  220  is to be performed. 
     Roughening the tool body at  220  may include roughening the tool body such that a roughness of the roughened tool surface is within a predefined roughness range. Examples of the predefined roughness range are discussed herein. 
     The roughening at  220  may include roughening in any suitable manner. As examples, the roughening at  220  may include abrading the tool body, grit blasting the tool body, sanding the tool body, knurling the tool body, patterning the tool body, lithographically patterning the tool body, etching the tool body, chemically etching the tool body, and/or laser etching the tool body. 
     It is within the scope of the present disclosure that the roughening at  220  may include randomly roughening the tool body. Additionally or alternatively, it is also within the scope of the present disclosure that the roughening at  220  may include systematically, or selectively, patterning the tool body. As an example, the roughening at  220  may include creating one or more roughened regions on the tool body. The roughened regions may be proximal to and/or overlapping with one another. Additionally or alternatively, the roughened regions also may be spaced apart from one another. Regardless of the exact mechanism, the roughening at  220  may include creating a network of interconnected fluid flow pathways that is at least partially defined by the tool body. 
       FIG. 7  is a flowchart depicting methods  300 , according to the present disclosure, of forming a thermoset composite structure. Methods  300  include locating an initial layer of material on a roughened tool surface at  305 , applying a retention vacuum at  310 , and locating a plurality of plies of thermoset composite material at  315 . Methods  300  further may include compacting a thermoset composite layup on the roughened tool surface at  320  and include releasing the retention vacuum at  325 , removing the thermoset composite layup from the roughened tool surface at  330 , and locating the thermoset composite layup on a second tool surface of a second tool at  335 . Methods  300  further may include compacting the thermoset composite layup on the second tool surface at  340  and include heating the second tool and the thermoset composite layup at  345 . Methods  300  also may include separating a thermoset composite structure from the second tool at  350 . 
     Locating the initial layer of material on the roughened tool surface at  305  may include locating any suitable initial layer of material on the roughened tool surface. Examples of the initial layer of material are disclosed herein with reference to initial layer  40  of  FIGS. 3-5 . 
     The roughened tool surface may be defined by a tool body of a first tool, and the first tool may be different from, separate from, and/or spaced apart from the second tool. The roughened tool surface may include a plurality of perforations that may be configured to provide fluid communication between the roughened tool surface (or an interface between the roughened tool surface and the initial layer) and a fluid manifold. The fluid manifold may be in fluid communication with the plurality of perforations and/or may be at least partially defined by the tool body. The first tool may include and/or be tool  100  of  FIGS. 3-5  and/or first tool  50  of  FIG. 5 . 
     Applying the retention vacuum at  310  may include applying the retention vacuum to the fluid manifold to retain the initial layer of material on the roughened tool surface. Application of the retention vacuum may generate a pressure differential across the initial layer of material, which may produce a pressure force that may be directed to retain the initial layer of material on the roughened tool surface. As discussed in more detail herein, the roughened tool surface may improve distribution and/or uniformity of the vacuum at the interface between the initial layer of material and the roughened tool surface. 
     Locating the plurality of plies of thermoset composite material at  315  may include locating the plurality of plies of thermoset composite material on the initial layer to define the thermoset composite layup. Additionally or alternatively, the locating at  315  also may be referred to herein as locating and/or receiving the plurality of plies of thermoset composite material on the roughened tool surface of the first tool. This may include sequentially, successively, consecutively, and/or serially locating the plurality of plies of thermoset composite material, one on top of the other, to form and/or define a layered stack of thermoset composite material that defines the thermoset composite layup. Examples of the plies of thermoset composite material are discussed herein with reference to plies  28  of  FIGS. 3-5 . Examples of thermoset composite layup  30  are discussed herein with reference to thermoset composite layup  30  of  FIGS. 3-5 . 
     Compacting the thermoset composite layup on the roughened tool surface at  320  may include compacting one or more plies of thermoset composite material that define the thermoset composite layup in any suitable manner. As an example, the compacting at  320  may include vacuum compacting the thermoset composite layup on the roughened tool surface. As another example, the compacting at  320  may include applying a compaction force to the thermoset composite layup utilizing any suitable compaction device. Examples of the compaction device are discussed herein with reference to first compaction device  54  of  FIG. 5 . 
     Regardless of the exact mechanism utilized, the compacting at  320  may include at least partially adhering the plurality of plies of thermoset composite material to one another, decreasing a spacing between adjacent plies of the plurality of plies of thermoset composite material, and/or removing a void space from within the thermoset composite layup. The compacting at  320  may be performed at any suitable time and/or with any suitable sequence during methods  300 . As examples, the compacting at  320  may be performed subsequent to the locating at  305 , subsequent to the applying at  310 , subsequent to the locating at  315 , during the locating at  315 , and/or prior to the releasing at  325 . When the compacting at  320  is performed during the locating at  315 , methods  300  may include locating a first portion of the plurality of plies of thermoset composite material on the initial layer, compacting the first portion of the plurality of plies of thermoset composite material, and subsequently locating a second portion of the plurality of plies of thermoset composite material on the first portion of the plurality of plies of thermoset composite material. This process may be repeated any suitable number of times during methods  300 . 
     Releasing the retention vacuum at  325  may include ceasing the applying at  310 . Subsequent to the releasing at  325 , the retention vacuum may dissipate, thereby decreasing (or eliminating) the pressure differential across the initial layer of material and decreasing (or eliminating) the pressure force that retains the initial layer of material on the roughened tool surface. In the systems and methods disclosed herein, and subsequent to the releasing at  325 , the roughened tool surface may permit, facilitate, and/or speed air flow to the interface between the initial layer and the roughened tool surface, thereby permitting, facilitating, and/or speeding the removing at  330 . 
     Removing the thermoset composite layup from the roughened tool surface at  330  may include separating the thermoset composite layup from the first tool. This may permit and/or facilitate the thermoset composite layup to be transferred to, received on, and/or located on the second tool surface of the second tool during the locating at  335 . The removing at  330  may be accomplished in any suitable manner. As an example, the removing at  330  may include permitting atmospheric air to enter the interface between the initial layer and the roughened tool surface. As another example, the removing at  330  may include applying a fluid pressure to the roughened tool surface (or to the interface), such as via the fluid manifold and/or the plurality of perforations, to provide and/or generate a motive force for separation of the initial layer of material from the roughened tool surface. 
     Locating the thermoset composite layup on the second tool surface of the second tool at  335  may include locating the thermoset composite layup on the second tool surface prior to, to permit, and/or to facilitate further processing. As an example, methods  300  further may include locating additional plies of composite material and/or additional thermoset composite layup(s) on the second tool surface of the second tool. As another example, the locating at  335  may include locating prior to, to permit, and/or to facilitate, the heating at  345 . 
     It is within the scope of the present disclosure that the locating at  335  and/or the further processing may include locating a plurality of discrete thermoset composite layups on the second tool surface of the second tool. The plurality of discrete thermoset composite layups may include the thermoset composite layup that was removed from the roughened tool surface during the removing at  330  as well as one or more additional, separate, and/or distinct thermoset composite layups. The one or more additional, separate, and/or distinct thermoset composite layups may be formed on the roughened tool surface of the first tool, such as via repeating the locating at  305 , the applying at  310 , the locating at  315 , the releasing at  325 , and the removing at  330 . Additionally or alternatively, the one or more additional, separate, and/or distinct thermoset composite layups may be formed in another manner and/or utilizing a different tool. Examples of shapes of the plurality of discrete thermoset composite layups are disclosed herein. 
     Compacting the thermoset composite layup on the second tool surface at  340  may include compacting the thermoset composite layup, or the plurality of discrete thermoset composite layups, in any suitable manner. As an example, the compacting at  340  may include vacuum compacting the thermoset composite layup on the second tool surface. As another example, the compacting at  340  may include applying a compaction force to the thermoset composite layup utilizing any suitable compaction device. Examples of the compaction device are discussed herein with reference to second compaction device  64  of  FIG. 5 . 
     Regardless of the exact mechanism utilized, the compacting at  340  may include at least partially adhering the thermoset composite layup to the second tool surface and/or to another thermoset composite layup that may be present on the second tool surface and/or in contact with the thermoset composite layup. The compacting at  340  may be performed at any suitable time and/or with any suitable sequence during methods  300 . As examples, the compacting at  340  may be performed subsequent to the locating at  305 , subsequent to the applying at  310 , subsequent to the locating at  315 , subsequent to the releasing at  325 , subsequent to the removing at  330 , subsequent to the locating at  335 , prior to the heating at  345 , and/or prior to the separating at  350 . 
     Heating the second tool and the thermoset composite layup at  345  may include heating to cure the thermoset composite layup and/or to define the thermoset composite structure. When the locating at  335  includes locating the plurality of discrete thermoset composite layups on the second tool surface, the heating at  345  may include heating, or heating all of, the plurality of discrete thermoset composite layups. 
     Separating the thermoset composite structure from the second tool at  350  may include separating to permit and/or facilitate use, utilization, operation, and/or further processing of the thermoset composite structure. The separating at  350  may be performed at any suitable time and/or with any suitable sequence during methods  300 . As an example, the separating at  350  may be performed subsequent to the heating at  345 . 
     Referring now to  FIGS. 8-9 , embodiments of the disclosure may be described in the context of an aircraft manufacturing and service method  900 , as shown in  FIG. 8 , and/or an aircraft  700 , as shown in  FIG. 9 . During pre-production, exemplary method  900  may include specification and design  905  of the aircraft  700  and material procurement  910 . During production, component and subassembly manufacturing  915  and system integration  920  of the aircraft  700  take place. Thereafter, the aircraft  700  may go through certification and delivery  925  in order to be placed in service  930 . While in service by a customer, the aircraft  700  is scheduled for routine maintenance and service  935  (which also may include modification, reconfiguration, refurbishment, and so on). 
     Each of the processes of method  900  may be 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 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. 9 , aircraft  700  produced by exemplary method  900  may include an airframe  710  with a plurality of systems  712  and an interior  714 . Examples of high-level systems  712  include one or more of a propulsion system  715 , an electrical system  716 , a hydraulic system  717 , and an environmental system  718 . 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. 
     System and methods embodied herein may be employed during any one or more of the stages of the manufacturing and service method  900 . For example, components or subassemblies corresponding to component and subassembly manufacturing process  915  may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft  700  is in service. Also, one or more system embodiments, method embodiments, or a combination thereof may be utilized during the production stages  915  and  920 , for example, by substantially expediting assembly of or reducing the cost of an aircraft  700 . Similarly, one or more of system embodiments, method embodiments, or a combination thereof may be utilized while the aircraft  700  is in service, for example and without limitation, to maintenance and service  935 . 
     Examples of inventive subject matter according to the present disclosure are described in the following enumerated paragraphs: 
     A1. A tool for receiving and forming a thermoset composite layup, the tool comprising: 
     a tool body that defines a roughened tool surface, wherein: 
     (i) the roughened tool surface is shaped to receive and to form a plurality of plies of thermoset composite material that defines the thermoset composite layup; and 
     (ii) a roughness of the roughened tool surface is within a predefined roughness range. 
     A2. The tool of paragraph A1, wherein the predefined roughness range extends between a minimum roughness and a maximum roughness. 
     A3. The tool of paragraph A2, wherein the minimum roughness has an average peak-to-valley height, Rz, as defined by ASME Y14.36M-1996, of 5 micrometers, 6 micrometers, 7 micrometers, 8 micrometers, 9 micrometers, 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, 18 micrometers, 19 micrometers, or 20 micrometers. 
     A4. The tool of any of paragraphs A2-A3, wherein the maximum roughness has an average peak-to-valley height, Rz, as defined by ASME Y14.36M-1996, of 100 micrometers, 90 micrometers, 80 micrometers, 70 micrometers, 60 micrometers, 50 micrometers, 40 micrometers, 30 micrometers, 25 micrometers, 20 micrometers, 18 micrometers, 16 micrometers, 15 micrometers, 14 micrometers, 13 micrometers, 12 micrometers, 11 micrometers, or 10 micrometers. 
     A5. The tool of any of paragraphs A1-A4, wherein the roughened tool surface includes at least one of: 
     (i) an abraded surface; 
     (ii) a grit blasted surface; 
     (iii) a sanded surface; 
     (iv) a knurled surface; 
     (v) a patterned surface; 
     (vi) a lithographically patterned surface; 
     (vii) an etched surface; 
     (viii) a chemically etched surface; and 
     (ix) a laser etched surface. 
     A6. The tool of any of paragraphs A1-A5, wherein the roughened tool surface further defines a plurality of perforations configured to provide fluid communication between the roughened tool surface and a fluid manifold that is in fluid communication with the plurality of perforations, optionally wherein the fluid manifold is at least partially defined by the tool body. 
     A7. The tool of paragraph A6, wherein the plurality of perforations defines an average distance between a given one of the plurality of perforations and a closest other of the plurality of perforations. 
     A8. The tool of paragraph A7, wherein the average distance is at least one of: 
     (i) at least 1 centimeter (cm), at least 2 cm, at least 3 cm, at least 4 cm, at least 5 cm, at least 6 cm, at least 7 cm, at least 8 cm, at least 9 cm, or at least 10 cm; and 
     (ii) less than 20 cm, less than 18 cm, less than 16 cm, less than 14 cm, less than 12 cm, less than 10 cm, less than 9 cm, less than 8 cm, less than 7 cm, less than 6 cm, or less than 5 cm. 
     A9. The tool of any of paragraphs A1-A8, wherein the tool is a layup mandrel. 
     A10. The tool of any of paragraphs A1-A9, wherein the tool is an inner mold line layup mandrel. 
     All. The tool of any of paragraphs A1-A10, wherein the tool is an outer mold line layup mandrel. 
     A12. The tool of any of paragraphs A1-A11, wherein the roughened tool surface is shaped to form the thermoset composite layup into one of: 
     (i) a stringer of a composite aircraft; 
     (ii) a skin of the composite aircraft; 
     (iii) at least a portion of a wing of the composite aircraft; and 
     (iv) at least a portion of a fuselage barrel of the composite aircraft. 
     A13. The tool of any of paragraphs A1-A12, wherein the roughened tool surface includes, and optionally is, a planar, or at least substantially planar, roughened tool surface. 
     A14. The tool of any of paragraphs A1-A13, wherein the roughened tool surface defines a surface contour in two, and optionally in only two, dimensions. 
     A15. The tool of any of paragraphs A1-A14, wherein the roughened tool surface defines a surface contour in three dimensions. 
     A16. The tool of any of paragraphs A1-A15, wherein the roughened tool surface defines a maximum extent of at least one of: 
     (i) at least 1 meter (m), at least 2 m, at least 3 m, at least 5 m, at least 10 m, at least 15 m, at least 20 m, at least 25 m, at least 30 m, at least 35 m, at least 40 m, at least 45 m, or at least 50 m; and 
     (ii) less than 100 m, less than 90 m, less than 80 m, less than 70 m, less than 60 m, less than 50 m, less than 40 m, less than 30 m, less than 25 m, less than 20 m, less than 15 m, or less than 10 m. 
     A17. The tool of any of paragraphs A1-A16, wherein the roughened tool surface has a surface area of at least one of: 
     (i) at least 0.5 square meters, at least 1 square meters, at least 2 square meters, at least 3 square meters, at least 4 square meters, at least 5 square meters, at least 6 square meters, at least 7 square meters, at least 8 square meters, at least 9 square meters, at least 10 square meters, at least 15 square meters, or at least 20 square meters; and 
     (ii) less than 100 square meters, less than 90 square meters, less than 80 square meters, less than 70 square meters, less than 60 square meters, less than 50 square meters, less than 40 square meters, less than 30 square meters, less than 20 square meters, less than 10 square meters, or less than 5 square meters. 
     B1. A system for forming a thermoset composite structure, the system comprising: 
     a first tool that includes the tool of any of paragraphs A1-A17, wherein the first tool is configured to receive a plurality of plies of thermoset composite material on the roughened tool surface, and further wherein the plurality of plies of thermoset composite material defines a thermoset composite layup; and 
     a second tool that defines a second tool surface configured to receive a plurality of discrete thermoset composite layups, which includes the thermoset composite layup, wherein the second tool further is configured to be heated with the plurality of discrete thermoset composite layups to cure the plurality of discrete thermoset composite layups and define the thermoset composite structure. 
     B2. The system of paragraph B1, wherein the second tool is configured to facilitate separation of the thermoset composite structure therefrom, optionally subsequent to the second tool being heated with the plurality of discrete thermoset composite layups. 
     B3. The system of any of paragraphs B1-B2, wherein the first tool is configured to facilitate separation of the thermoset composite layup from the roughened tool surface prior to curing of the thermoset composite layup, and optionally prior to receipt of the thermoset composite layup by the second tool surface of the second tool. 
     B4. The system of any of paragraphs B1-B3, wherein the system further includes a vacuum source. 
     B5. The system of paragraph B4, wherein the vacuum source is in selective fluid communication with a/the fluid manifold that is in fluid communication with a/the plurality of perforations that is defined by the roughened tool surface, and further wherein the vacuum source is configured to selectively apply a retention vacuum to the roughened tool surface via the plurality of perforations, and optionally wherein the fluid manifold is at least partially defined by the tool body. 
     B6. The system of paragraph B5, wherein the retention vacuum is configured to selectively retain an initial layer of material on the roughened tool surface, optionally wherein the initial layer of material includes at least one of (i) an initial ply of thermoset composite material and (ii) an intermediate layer that extends between the plurality of plies of thermoset composite material and the roughened tool surface. 
     B7. The system of any of paragraphs B1-B6, wherein the system further includes a fluid pressure source. 
     B8. The system of paragraph B7, wherein the fluid pressure source is in selective fluid communication with a/the fluid manifold that is in fluid communication with a/the plurality of perforations that is defined by the roughened tool surface, and further wherein the fluid pressure source is configured to selectively apply a fluid pressure to the roughened tool surface via the plurality of perforations, and optionally wherein the fluid manifold is at least partially defined by the tool body. 
     B9. The system of paragraph B8, wherein the fluid pressure source is configured to selectively provide a motive force for separation of an/the initial layer of material from the roughened tool surface, optionally wherein the initial layer of material includes at least one of (i) an/the initial ply of thermoset composite material and (ii) an/the intermediate layer that extends between the plurality of plies of thermoset composite material and the roughened tool surface. 
     B10. The system of any of paragraphs B1-B9, wherein the system includes the thermoset composite layup. 
     B11. The system of paragraph B10, wherein the thermoset composite layup is located on the roughened tool surface of the first tool. 
     B12. The system of any of paragraphs B10-B11, wherein the thermoset composite layup has been separated from the roughened tool surface of the first tool. 
     B13. The system of any of paragraphs B10-B12, wherein the thermoset composite layup is received on the second tool surface of the second tool. 
     B14. The system of any of paragraphs B1-B13, wherein the system includes the plurality of discrete thermoset composite layups. 
     B15. The system of paragraph B14, wherein the plurality of discrete thermoset composite layups is located on the second tool surface. 
     B16. The system of any of paragraphs B14-B15, wherein the plurality of discrete thermoset composite layups is uncured. 
     B17. The system of any of paragraphs B1-B16, wherein the system includes the thermoset composite structure. 
     B18. The system of paragraph B17, wherein the thermoset composite structure is located on the second tool surface. 
     B19. The system of any of paragraphs B1-B18, wherein the system further includes an/the intermediate layer that is located between the roughened tool surface and the thermoset composite layup. 
     B20. The system of paragraph B19, wherein the intermediate layer includes a release film configured to facilitate separation of the thermoset composite layup from the roughened tool surface. 
     B21. The system of any of paragraphs B19-B20, wherein the intermediate layer includes an isolation film configured to prevent direct physical contact between the thermoset composite layup and the roughened tool surface. 
     B22. The system of any of paragraphs B19-B21, wherein the intermediate layer includes a low surface energy material. 
     B23. The system of any of paragraphs B19-B22, wherein the intermediate layer includes a fluorinated polymer film. 
     B24. The system of any of paragraphs B19-B23, wherein the intermediate layer is a smooth, or at least substantially smooth, intermediate layer. 
     B25. The system of any of paragraphs B19-B23, wherein the intermediate layer is a textured intermediate layer. 
     B26. The system of any of paragraphs B1-B25, wherein the system further includes a compaction device. 
     B27. The system of paragraph B26, wherein the compaction device is configured to compact the plurality of plies of thermoset composite material on the roughened tool surface. 
     B28. The system of any of paragraphs B26-B27, wherein the compaction device is configured to compact the plurality of discrete thermoset composite layups on the second tool surface. 
     B29. The system of any of paragraphs B26-B28, wherein the compaction device includes at least one of (i) a vacuum bag and (ii) a vacuum chuck. 
     B30. The system of any of paragraphs B1-B29, wherein the system further includes a heating assembly configured to heat the second tool and the plurality of discrete thermoset composite layups to cure the plurality of discrete thermoset composite layups and define the thermoset composite structure. 
     B31. The system of paragraph B30, wherein the second tool and the plurality of discrete thermoset composite layups are being heated by the heating assembly. 
     B32. The system of any of paragraphs B30-B31, wherein the first tool is not being heated by the heating assembly. 
     C1. A method of forming a roughened tool surface on a tool body of a tool for receiving and forming a thermoset composite layup, the method comprising: 
     receiving the tool body; and 
     roughening the tool body such that a roughness of the roughened tool surface is within a predefined roughness range. 
     C2. The method of paragraph C1, wherein the roughening includes at least one of: 
     (i) abrading the tool body; 
     (ii) grit blasting the tool body; 
     (iii) sanding the tool body; 
     (iv) knurling the tool body; 
     (v) patterning the tool body; 
     (vi) lithographically patterning the tool body; 
     (vii) etching the tool body; 
     (viii) chemically etching the tool body; and 
     (ix) laser etching the tool body 
     C3. The method of any of paragraphs C1-C2, wherein the roughening includes randomly roughening the tool body. 
     C4. The method of any of paragraphs C1-C3, wherein the roughening includes systematically patterning the tool body. 
     C5. The method of any of paragraphs C1-C4, wherein the roughening includes creating a network of interconnected fluid flow pathways that is at least partially defined by the tool body. 
     C6. The method of any of paragraphs C1-05, wherein the tool includes the tool of any of paragraphs A1-A17. 
     D1. A method of forming a thermoset composite structure, the method comprising: 
     locating an initial layer of material on a roughened tool surface of a first tool, wherein the first tool includes a tool body that defines the roughened tool surface, and further wherein the roughened tool surface includes a plurality of perforations configured to provide fluid communication between the roughened tool surface and a fluid manifold that is in fluid communication with the plurality of perforations and optionally that is at least partially defined by the tool body; 
     applying a retention vacuum to the fluid manifold to retain the initial layer of material on the roughened tool surface; 
     locating a plurality of plies of thermoset composite material on the initial layer of material to define a thermoset composite layup; 
     releasing the retention vacuum; 
     removing the thermoset composite layup from the roughened tool surface of the first tool; 
     locating the thermoset composite layup on a second tool surface of a second tool; and 
     performing additional processing on the thermoset composite layup while the thermoset composite layup is located on the second tool surface of the second tool, optionally wherein the performing additional processing on the thermoset composite layup includes heating the second tool and the thermoset composite layup to cure the thermoset composite layup and define the thermoset composite structure. 
     D2. The method of paragraph D1, wherein, prior to the heating, the locating the thermoset composite layup includes locating a plurality of discrete thermoset composite layups, which includes the thermoset composite layup, on the second tool surface of the second tool, wherein the heating includes heating the second tool and the plurality of discrete thermoset composite layups to cure the plurality of discrete thermoset composite layups and define the thermoset composite structure. 
     D3. The method of paragraph D2, wherein the plurality of discrete thermoset composite layups is shaped to define at least two of: 
     (i) a stringer of a composite aircraft; 
     (ii) a skin of the composite aircraft; 
     (iii) at least a portion of a wing of the composite aircraft; and 
     (iv) at least a portion of a fuselage barrel of the composite aircraft. 
     D4. The method of any of paragraphs D1-D3, wherein the removing includes applying a fluid pressure to the roughened tool surface via the plurality of perforations to provide a motive force for separation of the initial layer of material from the roughened tool surface. 
     D5. The method of any of paragraphs D1-D4, wherein, subsequent to the heating, the method further includes separating the thermoset composite structure from the second tool. 
     D6. The method of any of paragraphs D1-D5, wherein the initial layer includes an intermediate layer that is located between the roughened tool surface and the thermoset composite layup. 
     D7. The method of paragraph D6, wherein the intermediate layer includes a release film configured to facilitate separation of the thermoset composite layup from the roughened tool surface. 
     D8. The method of any of paragraphs D6-D7, wherein the intermediate layer includes an isolation film configured to prevent direct physical contact between the thermoset composite layup and the roughened tool surface. 
     D9. The method of any of paragraphs D6-D8, wherein the intermediate layer includes a low surface energy material. 
     D10. The method of any of paragraphs D6-D9, wherein the intermediate layer includes a fluorinated polymer film. 
     D11. The method of any of paragraphs D6-D10, wherein the intermediate layer is a smooth, or at least substantially smooth, intermediate layer. 
     D12. The method of any of paragraphs D6-D10, wherein the intermediate layer is a textured intermediate layer. 
     D13. The method of any of paragraphs D1-D12, wherein the initial layer includes an initial ply of thermoset composite material. 
     D14. The method of any of paragraphs D1-D13, wherein, prior to the releasing, the method further includes compacting the thermoset composite layup on the roughened tool surface. 
     D15. The method of any of paragraphs D1-D14, wherein, prior to the heating, the method further includes compacting the thermoset composite layup, and optionally a/the plurality of discrete thermoset composite layups, on the second tool surface. 
     D16. The method of any of paragraphs D1-D15, wherein the first tool includes the tool of any of paragraphs A1-A17. 
     As used herein, the terms “selective” and “selectively,” when modifying an action, movement, configuration, or other activity of one or more components or characteristics of an apparatus, mean that the specific action, movement, configuration, or other activity is a direct or indirect result of user manipulation of an aspect of, or one or more components of, the apparatus. 
     As used herein, the terms “adapted” and “configured” mean that the element, component, or other subject matter is designed and/or intended to perform a given function. Thus, the use of the terms “adapted” and “configured” should not be construed to mean that a given element, component, or other subject matter is simply “capable of” performing a given function but that the element, component, and/or other subject matter is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing the function. It is also within the scope of the present disclosure that elements, components, and/or other recited subject matter that is recited as being adapted to perform a particular function may additionally or alternatively be described as being configured to perform that function, and vice versa. Similarly, subject matter that is recited as being configured to perform a particular function may additionally or alternatively be described as being operative to perform that function. 
     The various disclosed elements of apparatuses and steps of methods disclosed herein are not required to all apparatuses and methods according to the present disclosure, and the present disclosure includes all novel and non-obvious combinations and subcombinations of the various elements and steps disclosed herein. Moreover, one or more of the various elements and steps disclosed herein may define independent inventive subject matter that is separate and apart from the whole of a disclosed apparatus or method. Accordingly, such inventive subject matter is not required to be associated with the specific apparatuses and methods that are expressly disclosed herein, and such inventive subject matter may find utility in apparatuses and/or methods that are not expressly disclosed herein. 
     As used herein, the phrase, “for example,” the phrase, “as an example,” and/or simply the term “example,” when used with reference to one or more components, features, details, structures, embodiments, and/or methods according to the present disclosure, are intended to convey that the described component, feature, detail, structure, embodiment, and/or method is an illustrative, non-exclusive example of components, features, details, structures, embodiments, and/or methods according to the present disclosure. Thus, the described component, feature, detail, structure, embodiment, and/or method is not intended to be limiting, required, or exclusive/exhaustive; and other components, features, details, structures, embodiments, and/or methods, including structurally and/or functionally similar and/or equivalent components, features, details, structures, embodiments, and/or methods, are also within the scope of the present disclosure.