Patent Publication Number: US-2022227475-A1

Title: Beaded composite structures and methods for manufacturing beaded composite structures

Description:
PRIORITY 
     This application claims priority from U.S. Ser. No. 63/139,509 filed on Jan. 20, 2021. 
    
    
     FIELD 
     This application relates to composite structures and, more particularly, to composite structures and methods for manufacturing composite structures. 
     BACKGROUND 
     Typical architectural designs for airplane wing components require separate blade stringer and vent stringer fabrication prior to bonding or co-cure. Separate manufacturing steps are costly and time-consuming. Additionally, typical architecture designs for airplane wings require the use of many parts that add weight to the overall structure. Further, the space between the upper and lower portions of airplane wings is typically confined and difficult to navigate during initial assembly and subsequent maintenance. Access to that space is limited once the airplane wing has been assembled. 
     Accordingly, those skilled in the art continue with research and development efforts in the field of manufacturing composite structures. 
     SUMMARY 
     Disclosed are beaded composite structures. 
     In one or more examples, the disclosed composite structure includes a first layer and a second layer connected to the first layer to form a layered structure. The second layer has a plurality of base portions abutting the first layer and a plurality of beaded portions protruding from the plurality of base portions. Each beaded portion of the plurality of beaded portions defines a channel between the first layer and the second layer. 
     Also disclosed are methods for manufacturing beaded composite structures. 
     In one or more examples, the disclosed method for manufacturing composite structures includes depositing composite material over a tool to form a second layer. The second layer has a plurality of beaded portions and a plurality of base portions. The method further includes distributing a plurality of mandrels over the second layer to define channels in the plurality of beaded portions. The method further includes depositing composite material over the second layer and the plurality of mandrels to form a first layer. The method further includes bonding the first layer to the second layer. 
     Other examples of the disclosed beaded composite structures and methods for manufacturing beaded composite structures will become apparent from the following detailed description, the accompanying drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a composite structure; 
         FIG. 2A  is a perspective view of a beaded portion of a composite structure; 
         FIG. 2B  is a perspective view of a beaded portion of the composite structure of  FIG. 1 ; 
         FIG. 3A  is a top plan view of a wing of an airplane; 
         FIG. 3B  is a perspective view of a beaded portion of the wing of  FIG. 3A ; 
         FIG. 4  is a perspective view of a portion of the composite structure of  FIG. 1 ; 
         FIG. 5A  is a flowchart of a method for manufacturing the composite structure of  FIG. 1 ; 
         FIG. 5B  is a flowchart of a portion of the method of  FIG. 5A ; 
         FIG. 5C  is a flowchart of a portion of the method of  FIG. 5A ; 
         FIG. 6  is a perspective view of a composite structure; 
         FIG. 7  is a block diagram of aircraft production and service methodology; and 
         FIG. 8  is a schematic illustration of an aircraft. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, numerous specific details are set forth to provide a thorough understanding of the disclosed concepts, which may be practiced without some or all of these particulars. In other instances, details of known devices and/or processes have been omitted to avoid unnecessarily obscuring the disclosure. While some concepts will be described in conjunction with specific examples, it will be understood that these examples are not intended to be limiting. 
     Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, e.g., a “second” item does not require or preclude the existence of, e.g., a “first” or lower-numbered item, and/or, e.g., a “third” or higher-numbered item. 
     Reference herein to “one or more examples” means that one or more feature, structure, or characteristic described in connection with the example is included in at least one implementation. The phrase “one or more examples” in various places in the specification may or may not be referring to the same example. 
     As used herein, a system, apparatus, structure, article, element, component, or hardware “configured to” perform a specified function is indeed capable of performing the specified function without any alteration, rather than merely having potential to perform the specified function after further modification. In other words, the system, apparatus, structure, article, element, component, or hardware “configured to” perform a specified function is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing the specified function. As used herein, “configured to” denotes existing characteristics of a system, apparatus, structure, article, element, component, or hardware which enable the system, apparatus, structure, article, element, component, or hardware to perform the specified function without further modification. For purposes of this disclosure, a system, apparatus, structure, article, element, component, or hardware described as being “configured to” perform a particular function may additionally or alternatively be described as being “adapted to” and/or as being “operative to” perform that function. 
     Illustrative, non-exhaustive examples of the subject matter, disclosed herein, are provided below. 
       FIG. 1  illustrate a perspective view of a composite structure  100  that includes a first layer  110  and a second layer  120 . The first layer  110  is connected to the second layer  120  to form a layered structure  105 . While the composite structure  100  is shown in  FIG. 1  as a skin panel of an aircraft wing, those skilled in the art will appreciate that the disclosed composite structures  100  may be used in various applications, including various non-aerospace applications. 
     In one or more examples, the second layer  120  of the composite structure  100  includes a plurality of base portions  140  and a plurality of beaded portions  130 . The plurality of base portions  140  may abut the first layer  110  within the layered structure  105  of the composite structure  100 . The plurality of beaded portions  130  may protrude from the plurality of base portions  140 . Therefore, each beaded portion  130  of the plurality of beaded portions  130  defines an associated channel  135  between the first layer  110  and the second layer  120  such that the composite structure  100  includes a plurality of channels  135 . 
     In one or more examples, at least one system feature  300  may be disposed in at least one channel  135  of the plurality of channels  135 . The system feature  300  may be, for example, a wire  310 , a conduit  320 , a cable, a tube, optical fiber, or the like. Various other system features  300  may be received within the plurality of channels  135  without departing from the scope of the present disclosure. 
     In one or more examples, the second layer  120  of the composite structure  100  may be formed from or may include a composite material. The composite material of the second layer  120  may include a reinforcement material encapsulated in a polymeric matrix material. As a specific, non-limiting example, the reinforcement material may be (or may include) carbon fibers, glass fibers or the like, while the polymeric matrix material may be (or may include) thermoset (e.g., epoxy) resin. The use of various thermoplastic resins, such as a polyaryletherketone, is also contemplated. 
     In one or more examples, the layered structure  105  of the composite structure  100  defines one or more access openings  150 . In one variation, the access opening  150  extends through both the first layer  110  and the second layer  120 . In another variation, the access opening  150  extends through only the first layer  110  of the layered structure  105 . In yet another variation, the access opening  150  extends through only the second layer  120  of the layered structure  105 . Therefore, an access opening  150  may be located in a beaded portion  130  of the plurality of beaded portions  130  ( FIG. 6 ), on a base portion  140  of the plurality of base portions  140 , or the composite structure  100  includes more than one access opening  150  wherein at least one access opening  150  is located in a beaded portion  130  and at least one access opening  150  is located on a base portion  140 . 
     The at least one access opening  150 , illustrated in  FIG. 6 , allows for access to a beaded portion  130  of the plurality of beaded portions  130  for maintenance. One or more system features  300  may be located in a beaded portion  130  of the plurality of beaded portions  130 . The access opening  150  allows for the one or more system features  300  to pass outside of the beaded portion  130 . 
     As shown in  FIG. 1 , in one or more examples, the composite structure  100  may further include an access panel  151  ( FIG. 1 ) sealing at least one access opening  150 . The access panel  151  can be fluid-tight such that is keeps fluid from passing through the associated access opening  150 . The access panel  151  (fuel dam) is configured to be easily accessible for inspection and repair from outside an aircraft wing  170 , thus reducing the need to enter a confined space. 
     In one or more examples, the first layer  110  of the composite structure  100  is substantially free of beaded portions  130 . Alternatively, while not shown in the drawings, the first layer  110  may include a plurality of beaded portions  130  and a plurality of base portions  140 , similar to the second layer  120 . 
     In one or more examples, the first layer  110  of the composite structure  100  may be formed from or may include a composite material. The composite material of the first layer  110  may include a reinforcement material encapsulated in a polymeric matrix material. As a specific, non-limiting example, the reinforcement material may be (or may include) carbon fibers, glass fibers or the like, while the polymeric matrix material may be (or may include) thermoset (e.g., epoxy) resin. The use of various thermoplastic resins, such as a polyaryletherketone, is also contemplated. 
     As best shown in  FIGS. 2A and 2B , in one or more examples, the first layer  110  may define an access opening  150  providing access to the channel  135  ( FIG. 1 ) between the first layer  110  and the second layer  120 . Those skilled in the art will appreciate that the composite structure  100  may include more than one access opening  150  providing access to the plurality of channels  135  ( FIG. 1 ). 
       FIG. 2A  and  FIG. 2B  illustrate two examples of the beaded portions  130  of the plurality of beaded portions  130 . Specifically,  FIG. 2A  illustrates a beaded portion  130  that is generally hat-shaped in cross-section, while  FIG. 2B  illustrates a beaded portion  130  having a generally rounded shape in cross-section. 
     As shown in  FIG. 2A , each beaded portion  130  of the plurality of beaded portions  130  may include opposed sidewall portions  132  and a cap portion  134  extending between the sidewall portions  132 . In one or more examples, the plurality of base portions  140  have a nominal first cross-sectional thickness T 1 , the sidewall portions  132  have a nominal second cross-sectional thickness T 2 , the cap portion  134  has a nominal third cross-sectional thickness T 3 . In one or more examples, the nominal third cross-sectional thickness T 3  is substantially greater (e.g., at least 5 percent greater, such as at least 20 percent greater) than the nominal first cross-sectional thickness T 1  and substantially greater (e.g., at least 5 percent greater, such as at least 20 percent greater) than the nominal second cross-sectional thickness T 2 . In one or more examples, the nominal first cross-sectional thickness T 1  is substantially the same as the nominal second cross-sectional thickness T 2 . In one or more examples, the nominal first cross-sectional thickness T 1 , the nominal second cross-sectional thickness T 2 , and the nominal third cross-sectional thickness T 3  are substantially the same. 
     As illustrated in  FIG. 2A , the first layer  110  has a nominal fourth cross-sectional thickness T 4  proximate each base portion  140  of the plurality of base portions  140  of the second layer  120 . The first layer  110  further has a nominal fifth cross-sectional thickness T 5  below each beaded portion  130  of the plurality of beaded portions  130 . In one or more examples, the nominal fifth cross-sectional thickness T 5  is substantially the same as a sum of the first cross-sectional thickness T 1  and the nominal fourth cross-sectional thickness T 4 . The nominal fifth cross-sectional thickness T 5  is greater than the nominal fourth cross-sectional thickness T 4  such that the second layer  120  is configured to self-nest with the first layer  110 . In one or more examples, the nominal fifth cross-sectional thickness T 5  is substantially the same as the nominal third cross-sectional thickness T 3 . 
     Referring to  FIG. 2B , when one or more beaded portions  130  of the plurality of beaded portions  130  has a rounded shape in cross-section, the rounded beaded portion  130  may have a nominal width W 1  and a nominal height H 1 . In one or more examples, a ratio of the nominal height H 1  to the nominal width W 1  may be less than 1. In other examples, a ratio of the nominal height H 1  to the nominal width W 1  is approximately 1. In yet other examples, as illustrated in  FIG. 2B , each beaded portion  130  of the plurality of beaded portions  130  is elongated such that it has a generally oval shape. 
     In one or more examples, as illustrated in  FIG. 3B , each beaded portion  130  of the plurality of beaded portions  130  includes a tapered end cap  138  that transitions to a base portion  140  of the plurality of base portions  140 . The tapered end cap  138  has a flared geometry to transition from a hat shape or round shape beaded portion  130  to a generally planar portion of the second layer  120 . In one or more examples, the tapered end cap  138  is integrated with the second layer  120  such that they are a single monolithic body. In one or more examples, the tapered end cap  138  is formed separately, such as punch formed, and then co-cured with the second layer  120  for integration. 
     As illustrated in  FIGS. 2A and 2B , the layered structure  105  defines a transition region  136  where the second layer  120  transitions from a base portion  140  of the plurality of base portions  140  to a beaded portion  130  of the plurality of beaded portions  130 . In one or more examples, a filler material  155  is disposed in the transition region  136  between the first layer  110  and the second layer  120 . The filler material  155  defines a fillet region within the transition region  136 . In one or more examples, the filler material  155  is co-cured with at least one of the first layer  110  or the second layer  120  of the layered structure  105 . 
       FIG. 4  illustrates a portion of an exemplary embodiment of the second layer  120 . In one or more examples, the second layer  120  includes at least one integral flange  128 . The integral flange  128  is configured to align with a spar  175 . In one or more examples, the integral flange  128  is substantially parallel with a spar  175 . 
     In one or more examples, the first layer  110  and the second layer  120  of the disclosed composite structure  100  may be co-cured, thereby yielding the layered structure  105  of the composite structure  100 . Alternatively, the layered structure  105  of the disclosed composite structure  100  may include an adhesive (not shown) disposed between the first layer  110  and the second layer  120 . The adhesive may be positioned between a first major surface  112  ( FIG. 2B ) of the first layer  110  and a second major surface  122  ( FIG. 2B ) of the second layer  120  along the base portions  140  of the second layer  120 . 
     As illustrated in  FIG. 3A , disclosed is an aircraft wing  170 . The aircraft wing  170  may be generally tapered in shape. In one or more examples, the aircraft wing  170  includes a lower skin panel  190  and an upper skin panel  180 . At least one of the upper skin panel  180  and the lower skin panel  190  includes the disclosed composite structure  100  comprised of a first layer  110  and a second layer  120 . The second layer  120  is connected to the first layer  110  to form a layered structure  105 . In one or more examples, the second layer  120  includes a plurality of base portions  140  abutting the first layer  110 . The second layer  120  further includes a plurality of beaded portions  130  protruding from the plurality of base portions  140 . In one or more examples, each beaded portion  130  of the plurality of beaded portions  130  defines a channel  135  between the first layer  110  and the second layer  120 . The plurality of beaded portions  130  may include approximately eight beaded portions  130 . In one or more examples, at least one system feature  300  is disposed in the plurality of channels  135 . The system feature  300  is one of a wire  310 , a conduit  320 , or any other system feature  300  provided therein. 
     In one or more examples, as illustrated in  FIG. 1 , both the upper skin panel  180  and the lower skin panel  190  have a layered structure  105  including a first layer  110  and a second layer  120 . The second layer  120  is connected to the first layer  110  to form the layered structure  105 . In one or more examples, the second layer  120  includes a plurality of base portions  140  abutting the first layer  110 . The second layer  120  further includes a plurality of beaded portions  130  protruding from the plurality of base portions  140 . In one or more examples, each beaded portion  130  of the plurality of beaded portions  130  defines a channel  135  between the first layer  110  and the second layer  120 . The plurality of beaded portions  130  may include approximately 8 of each beaded portion  130 . In one or more examples, at least one system feature  300  is disposed in the plurality of channels  135 . The system feature  300  is one of a wire  310 , a conduit  320 , or any other system feature  300  provided therein. 
     In one or more examples, the aircraft wing  170  includes a fluid-tight volume  177  defined, at least partially, by the upper skin panel  180 , the lower skin panel  190 , and the spar  175 . The plurality of channels  135  are fluidly isolated from the fluid-tight volume  177  such that no liquid contaminates any system feature  300  disposed within a channel  135  of the plurality of channels  135 . In one or more examples, the aircraft wing  170  includes at least one rib  173  disposed between the upper skin panel  180  and the lower skin panel  190 . The at least one rib  173  defines a fluid-tight volume  177  with the upper skin panel  180 , the lower skin panel  190 , and the spar  175 . In one or more examples, the aircraft wing  170  includes more than one rib  173  that define more than one fluid-tight volume  177 . In one or more examples, at least one fluid-tight volume  177  is a fuel tank. 
       FIG. 5A  illustrates a flow diagram of a method  200  for manufacturing a composite structure  100 . The method  200  includes depositing  210  composite material over a tool to form a second layer  120 . The second layer  120  includes a plurality of beaded portions  130  and a plurality of base portions  140 . In one or more examples, the plurality of beaded portions  130  define a plurality of channels  135 . 
     In one or more examples, the method  200  includes distributing  220  a plurality of mandrels over the second layer  120  to define channels in the plurality of beaded portions  130 . In one or more examples, the distributing  220  the plurality of mandrels includes distributing  220  a plurality of dissolvable mandrels. In one or more examples, the plurality of dissolvable mandrels include a ceramic material. The ceramic material is dissolvable in water. In one or more examples, the plurality of beaded portions  130  define a plurality of channels  135 . 
     In one or more examples, the method  200  includes depositing  230  composite material over the second layer  120  and the plurality of mandrels to form a first layer  110 . The first layer  110  is substantially free of beaded portions  130 . 
     In one or more examples, the method  200  includes bonding  240  the first layer  110  to the second layer  120 . The bonding  240  is achieved by curing  253  one or more of the first layer  110  and the second layer  120  simultaneously or sequentially. Curing  253  may be performed in an autoclave. In one or more examples, the bonding  240  includes curing  253  the first layer  110 . In one or more examples, the bonding  240  includes curing  253  an adhesive disposed between the first layer  110  and the second layer  120 . In one or more examples, the bonding  240  includes curing  253  the second layer  120 . 
     In one or more examples, the method  200  for manufacturing a composite structure  100  includes connecting  250  a first layer  110  to a second layer  120  to form a layered structure  105 . The second layer  120  of the layered structure  105  includes a plurality of base portions  140  abutting the first layer  110  and a plurality of beaded portions  130  protruding from the plurality of base portions  140 . In one or more examples, each beaded portion  130  of the plurality of beaded portions  130  defines a channel  135  between the first layer  110  and the second layer  120 . 
     In one or more examples, the connecting  250  includes co-curing  259  the first layer  110  and the second layer  120  to form a layered structure  105 . 
       FIG. 5B  illustrates one exemplary embodiment of the connecting  250 . In one or more examples, the connecting  250  includes separately curing  253  the first layer  110  and the second layer  120  to yield a cured first layer  110 ′ and a cured second layer  120 ′. The connecting  250  further includes bonding  255  the cured first layer  110 ′ to the cured second layer  120 ′ to form a layered structure  105 . 
       FIG. 5C  illustrates another exemplary embodiment of the connecting  250 . In one or more examples, the connecting  250  includes curing one of the first layer  110  and the second layer  120  to yield a cured layer  106  and an uncured layer  108 . The connecting  250  further includes applying  257  an adhesive between the cured layer  106  and the uncured layer  108 . The connecting  250  further includes co-curing  259  the adhesive and the uncured layer  108  to form a layered structure  105 . 
     Examples of the subject matter disclosed herein may be described in the context of aircraft manufacturing and service method  1100  as shown in  FIG. 7  and aircraft  1102  as shown in  FIG. 8 . During pre-production, illustrative method  1100  may include specification and design (block  1104 ) of aircraft  1102  and material procurement (block  1106 ). During production, component and subassembly manufacturing (block  1108 ) and system integration (block  1110 ) of aircraft  1102  may take place. Thereafter, aircraft  1102  may go through certification and delivery (block  1112 ) to be placed in service (block  1114 ). While in service, aircraft  1102  may be scheduled for routine maintenance and service (block  1116 ). Routine maintenance and service may include modification, reconfiguration, refurbishment, etc. of one or more systems of aircraft  1102 . 
     Each of the processes of illustrative method  1100  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 vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on. 
     As shown in  FIG. 8 , aircraft  1102  produced by illustrative method  1100  may include airframe  1118  with a plurality of high-level systems  1120  and interior  1122 . Examples of high-level systems  1120  include one or more of propulsion system  1124 , electrical system  1126 , hydraulic system  1128 , and environmental system  1130 . Any number of other systems may be included. Although an aerospace example is shown, the principles disclosed herein may be applied to other industries, such as the automotive industry. Accordingly, in addition to aircraft  1102 , the principles disclosed herein may apply to other vehicles, e.g., land vehicles, marine vehicles, space vehicles, etc. 
     Apparatus(es) and method(s) shown or described herein may be employed during any one or more of the stages of the manufacturing and service method  1100 . For example, components or subassemblies corresponding to component and subassembly manufacturing (block  1108 ) may be fabricated or manufactured in a manner similar to components or subassemblies produced while aircraft  1102  is in service (block  1114 ). Also, one or more examples of the apparatus(es), method(s), or combination thereof may be utilized during production stages (block  1108  and block  1110 ), for example, by substantially expediting assembly of or reducing the cost of aircraft  1102 . Similarly, one or more examples of the apparatus or method realizations, or a combination thereof, may be utilized, for example and without limitation, while aircraft  1102  is in service (block  1114 ) and/or during maintenance and service (block  1116 ). 
     Different examples of the apparatus(es) and method(s) disclosed herein include a variety of components, features, and functionalities. It should be understood that the various examples of the apparatus(es) and method(s), disclosed herein, may include any of the components, features, and functionalities of any of the other examples of the apparatus(es) and method(s) disclosed herein in any combination. 
     Although various examples of the disclosed beaded composite structures and methods for manufacturing beaded composite structures have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims. 
     Therefore, it is to be understood that the subject matter, disclosed herein, is not to be limited to the specific examples illustrated and that modifications and other examples are intended to be included within the scope of the appended claims. Moreover, although the foregoing description and the associated drawings describe examples of the subject matter, disclosed herein, in the context of certain illustrative combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative implementations without departing from the scope of the appended claims. Accordingly, parenthetical reference numerals in the appended claims are presented for illustrative purposes only and are not intended to limit the scope of the claimed subject matter to the specific examples provided herein.