Method of manufacturing a composite substrate, composite laminate, vehicle, wing assembly

Abstract

The invention provides methods of manufacturing composite substrates, composite laminates, vehicles, wing assemblies. Methods of machining a composite substrate are disclosed, the method comprising: integrating a predetermined pattern area with a release material for the purpose of forming a release area at a predetermined thickness in the composite substrate, detecting the release area, and forming a plurality of recesses in the composite substrate by removing a machined plug from the composite substrate to form a recess disposed at a location corresponding to the predetermined pattern area, and composite parts comprising recesses machined according to such methods are disclosed.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to the field of composite materials and structures and components made from composite materials. More particularly, the present disclosure relates to the field of machining composite materials used as composite material components without sacrificing the strength of the composite materials and manufacturing composite components using the machined composite materials. BACKGROUND

[0002] Aircraft structures including, for example, wing structures, typically include complex assemblies containing stringers, ribs, beams, etc. as stiffening structures within the interior of the wing assembly. The ribs are typically arranged vertically in space along the longitudinal length of the wing interior. The stringers are typically connected to the wing skin, with the ribs and beams connected to the stringer assemblies to form a stiffened wing box assembly having the desired strength and stiffness. The stringers typically extend along the longitudinal length of the wing interior.

[0003] Aircraft wings constructed with stiffening stringers, ribs, and fasteners are expensive at the component level and also add to the overall cost of the wing assembly process and also add to the overall cost of structures incorporating such components and assemblies. In addition, the interior wing components typically used as wing stiffeners, as well as the fasteners used to connect the stiffeners, add a substantial amount of weight to the wing components and add to the overall weight of the aircraft incorporating such wing assemblies. SUMMARY

[0004] According to aspects of the present disclosure, a method is disclosed that includes orienting a plurality of composite material layers onto a tool to form a composite material substrate, wherein the composite material substrate has a composite material substrate thickness, and wherein the tool includes a tool surface. The composite material substrate also includes a composite material substrate first surface (e.g., a composite material substrate first surface first side) and a composite material substrate second surface (e.g., a composite material substrate first surface second side), wherein the composite material substrate first surface is disposed proximate to the tool surface. The method also includes introducing a predetermined pattern region to the composite material substrate, wherein the predetermined pattern region is configured to be introduced to the composite material substrate at a predetermined distance from the composite material substrate second surface at a location within the composite material substrate thickness; at least partially curing the composite material substrate to form an amount of at least partially cured composite material substrate, wherein the at least partially cured composite material substrate is configured to extend from the composite material substrate second surface a predetermined distance into the composite material substrate to form a predetermined amount of at least partially cured composite material substrate.

[0005] The method further includes removing the predetermined amount of at least a portion of the at least partially cured composite material substrate from the composite material substrate to the predetermined distance from the second surface of the composite material substrate within the thickness of the composite material substrate to form a predetermined recessed pattern in the at least partially cured composite material substrate, wherein the predetermined recessed pattern substantially matches the predetermined patterned region.

[0006] In another aspect, introducing the predetermined patterned region to the composite material substrate further includes at least partially curing the predetermined patterned region in the composite material substrate.

[0007] In a further aspect, introducing the predetermined patterned region to the composite material substrate further includes chemically processing the predetermined patterned region into the composite material substrate.

[0008] In another aspect, introducing the predetermined patterned region to the composite material substrate further includes layering an intermediate layer in the composite material substrate, wherein the intermediate layer is layered at the predetermined distance from the second surface of the composite material substrate in the composite material substrate, and wherein the intermediate layer includes the predetermined patterned region.

[0009] In a further aspect, at least partially curing the composite material substrate further includes orienting a heat blanket proximate the second surface of the composite material substrate, wherein the heat blanket includes a plurality of heating zones, and wherein the plurality of heating zones are configured to at least partially cure the composite material substrate to a predetermined cured thickness, and the plurality of heating zones are configured to at least partially cure the composite material substrate to form the at least partially cured predetermined patterned region into the composite material substrate.

[0010] In another aspect, the composite material layer includes an epoxy-based composite material including fibers.

[0011] In a further aspect, the composite material layer includes an epoxy-based composite material including carbon fibers.

[0012] In another aspect, the at least partially cured predetermined patterned region includes a porosity value that is different than a porosity value of the composite material substrate.

[0013] In another aspect, the method further includes chemically processing the predetermined patterned region into the composite material substrate by applying a chemical agent at a location within the thickness of the composite material substrate during fabrication of the composite material substrate to form the predetermined patterned region.

[0014] In another aspect, the at least partially cured predetermined patterned region has a porosity value that is different than a porosity value of the composite material substrate.

[0015] In a further aspect, the intermediate layer is configured to form a predetermined peel pattern region.

[0016] According to another aspect, a method is disclosed, the method comprising the steps of: providing a heterogeneous composite substrate comprising a heterogeneous composite substrate surface, the heterogeneous composite substrate further having a predetermined composite substrate thickness, wherein the heterogeneous composite substrate further comprises a first region of a composite substrate having a first porosity and a second region positioned adjacent to the first region of the composite substrate, wherein the second region comprises a second porosity, and wherein the second region is provided at a predetermined distance from the heterogeneous composite substrate surface within the predetermined composite substrate thickness.

[0017] The method further comprises at least partially solidifying a predetermined region of the first region of the composite substrate, wherein the predetermined region of the first region of the composite substrate is configured to extend from the heterogeneous composite substrate surface to the second region to form a predetermined amount of at least partially solidified first region of the composite substrate.

[0018] The method further comprises orienting a material removal device proximate to the heterogeneous composite substrate surface and determining a location of a first region composite substrate / second region interface in the heterogeneous composite substrate.

[0019] The method further comprises removing a predetermined amount of at least partially solidified first region composite substrate from the heterogeneous composite substrate, wherein the predetermined amount of at least partially solidified first region composite substrate extends from the heterogeneous composite substrate surface to the first region composite / second region interface.

[0020] In another aspect, the disclosure relates to a composite laminate comprising: a composite substrate configured to comprise a plurality of recesses in the composite substrate extending a predetermined distance from a composite substrate surface, the recesses comprising a predetermined size; an intermediate layer provided at a predetermined depth within the composite substrate, wherein the intermediate layer comprises an intermediate layer first surface and an intermediate layer second surface, wherein the recesses are bounded by a surrounding composite substrate and the intermediate layer first surface; and wherein the intermediate layer comprises a release material.

[0021] In another aspect, the present disclosure is directed to a vehicle comprising a composite laminate, wherein the composite laminate comprises: a composite substrate configured to comprise a plurality of recesses extending a predetermined distance from a composite substrate surface into the composite substrate, the recesses comprising a predetermined size; an intermediate layer disposed at a predetermined depth within the composite substrate, wherein the intermediate layer comprises an intermediate layer first surface and an intermediate layer second surface, wherein the recesses are bounded by surrounding composite substrate and the intermediate layer first surface; and wherein the intermediate layer comprises a release material.

[0022] In another aspect, the vehicle comprises at least one of: a manned aircraft; an unmanned aircraft; a manned spacecraft; an unmanned spacecraft; a manned rotorcraft; an unmanned rotorcraft; a manned land vehicle; an unmanned ground vehicle; a manned water-borne watercraft; an unmanned water-borne watercraft; a manned underwater watercraft; an unmanned underwater watercraft; and combinations thereof.

[0023] In another aspect, a wing assembly is disclosed, wherein the wing assembly comprises a composite laminate, wherein the composite laminate comprises: a composite substrate configured to comprise a plurality of recesses extending a predetermined distance from a composite substrate surface into the composite substrate, the recesses comprising a predetermined size; an intermediate layer disposed at a predetermined depth within the composite substrate, wherein the intermediate layer comprises an intermediate layer first surface and an intermediate layer second surface, wherein the recesses are bounded by surrounding composite substrate and the intermediate layer first surface; and wherein the intermediate layer comprises a release material.

[0024] The features, functions, and advantages that have been discussed can be implemented independently in various examples or can be implemented in combination in other examples, as will be discovered by those of ordinary skill in the art upon reading the following description and viewing the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] By thus generally describing aspects of the present disclosure, reference will now be made to the drawings, which are not necessarily drawn to scale, and wherein:

[0026] Figure 1 is an illustration of a wing assembly according to aspects of the present disclosure;

[0027] Figure 2A is a perspective view of a wing assembly configuration according to aspects of the present disclosure;

[0028] Figure 2B is a cross-sectional view of a wing assembly according to aspects of the present disclosure; Figure 1

[0029] Figure 3 is an illustration of a vehicle comprising a wing assembly according to aspects of the present disclosure; ​

[0030] Figure 4A is a side view of a manufacturing stage according to aspects of the present application;

[0031] Figure 4B is a side view of a manufacturing stage according to aspects of the present application;

[0032] Figure 4C is a side view of a manufacturing stage according to aspects of the present application;

[0033] Figure 4D is a side view of a manufacturing stage according to aspects of the present application;

[0034] Figure 4E is a side view of a manufacturing stage according to aspects of the present application;

[0035] Figure 5 is a top view of a processed composite material substrate according to aspects of the present application;

[0036] Figure 6A is a side cut view of a composite material substrate being processed to form recesses in the composite material substrate thickness according to aspects of the present application;

[0037] Figure 6B is a top view of a portion of a composite material substrate showing a plurality of recesses to be processed in the composite material substrate according to aspects of the present application; Figure 6A

[0038] Figure 7 is a perspective view of a processed composite material substrate having a plurality of recesses with a geometric profile comprising a predetermined triangular pattern according to aspects of the present application;

[0039] Figure 8 is a perspective view of a processed composite material substrate having a recess geometric profile comprising a predetermined triangular pattern according to aspects of the present application;

[0040] Figure 9 is a perspective view of a processed composite material substrate having a recess geometric profile comprising a predetermined rectangular pattern according to aspects of the present application;

[0041] Figure 10A is a flow chart outlining a method according to aspects of the present application;

[0042] Figure 10B is a flow chart outlining a method according to aspects of the present application;

[0043] Figure 10C is a flow chart outlining a method according to aspects of the present application;

[0044] Figure 11 ​This is a flowchart outlining a method according to aspects of the present invention; and

[0045] Figure 12 This is a flowchart outlining a method according to an aspect of the present invention. Detailed Implementation

[0046] This disclosure relates in several aspects to composite material structures, which can be two-piece structures, one of which can be a composite material substrate. The composite material substrate is processed by removing a portion of it using a material removal device to form a predetermined material removal pattern, thereby forming a processed composite material substrate. The material removal can form at least one recess in the composite material substrate. The processed composite material substrate is then bonded to a top composite material layer, such that the at least one recess is covered by the top composite material layer.

[0047] Figure 1 It shows that it can be configured to attach to ( Figure 3 The image shows a top-view perspective view of the composite components of the aircraft, presented in the form of a non-restricted wing assembly. Figure 1 As shown, Figure 1 The composite component 10 shown is in the form of an exemplary wing assembly. The composite component 10 includes a two-piece assembly comprising a composite substrate 12, the composite substrate 12 including recesses 14 appearing in a predetermined pattern 11 within the composite substrate 12, wherein each recess further includes a predetermined geometric profile (in...). Figure 1 (As shown in the image, a predetermined rectangular pattern). Figure 1 As further shown, the wing assembly 10 also includes a composite material top layer 20, which is fixedly attached to the composite material substrate 12.

[0048] Figure 2A yes Figure 1 A perspective view of the composite component 10 shown in the figure. (As shown) Figure 2A As shown, the composite component 10 is also illustrated in an exemplary form as a wing assembly and includes a two-piece assembly comprising a composite substrate 12, the composite substrate 12 including recesses 14 appearing in the composite substrate 12 in a predetermined pattern 11, wherein each recess further includes a predetermined geometric profile (in Figure 1 (The pattern is shown as a predetermined rectangular shape). Figure 2A A composite material top layer 20 is also shown, which includes a first surface 20a and a second surface 20b.

[0049] Figure 2B It was cut along section line "AA". Figure 1 The cross-sectional view of the composite component is shown in the image. Figure 2BAs shown, composite component 10 is also illustrated in an exemplary form as a wing assembly and includes a two-piece assembly comprising a composite substrate 12. The composite substrate also includes a first surface 12a, a second surface 12b, and a recess 14. (See diagram below.) Figure 1 , Figure 2A and Figure 2B As shown, recesses 14 appear in a predetermined pattern 11 in the composite substrate 12, wherein each recess 14 further includes a predetermined geometric profile (in Figure 1 , Figure 2A and Figure 2B (As shown in the image, a predetermined rectangular pattern). Figure 2B As further shown, the composite component 10 also includes a composite material top layer 20, which is fixedly attached to the composite material substrate 12. The composite material top layer 20 includes a first surface 20a and a second surface 20b. The recess 14 is shown as being bounded by the recess wall 18, the recess bottom 16, and the second surface 20b of the composite material top layer. Figure 2B As shown, the adhesive material layer 26 is inserted between the second surface 12b of the composite substrate and the second surface 20b of the composite top layer.

[0050] Figure 3 This is a representative illustration of a vehicle 30 in a non-restricted form, showing wings 32 including, for example, those disclosed herein. Figure 1 , Figure 2A , Figure 2B and Figure 3 Composite component 10 of any of the types shown in the figures. Although the composite substrate is shown in the figures as being incorporated into the wing assembly of an aircraft, according to aspects of the invention, composite components (comprising processed composite substrates, wherein recesses are machined into the composite substrate) may be used in the manufacture of other aircraft and other vehicle components (including, for example, tail vertical stabilizer 34, tail horizontal stabilizer 36, etc.) other than components in vehicles, such as those in vehicles, including, but not limited to: manned aircraft; unmanned aircraft; manned spacecraft; unmanned spacecraft; manned rotorcraft; unmanned rotorcraft; manned land vehicles; unmanned ground vehicles; manned water vehicles; unmanned water vehicles; manned underwater vehicles; unmanned underwater vehicles; or combinations thereof.

[0051] Figure 4A , Figure 4B , Figure 4C , Figure 4D and Figure 4E (collectively referred to in this article) Figures 4A to 4E) represents an exemplary progression of material manufacturing stages (e.g., the five stages shown as first stage 40A, second stage 40B, third stage 40C, fourth stage 40D, and fifth stage 40E) in the manufacture of the presently disclosed composite components according to the present application. As shown in Figure 4A The initial stage or first stage 40A shows a mold 42 having a mold surface 42a onto which (at a predetermined thickness) a predetermined amount of uncured composite material base 44 is deposited. The composite material base has a first face 44a of the composite material base in contact with the mold 42 and a second face 44b of the composite material base. According to aspects of the present application, the uncured composite material base 44 of predetermined thickness is deposited onto the mold 42 to form a cured composite material base of predetermined thickness, taking into account composite material shrinkage during curing. According to aspects of the present application, non-limiting representative composite materials for making the composite material base and the composite material base and / or the composite material top layer can include resin-containing materials such as, for example, diglycidyl ether of bisphenol A; diglycidyl ether of bisphenol F; N,N,N',N'-tetraalkylalkylene-4,4'-diaminodiphenyl methane; p-aminophenol triglycidyl ether; epoxy phenol novolac resin; epoxy cresol novolac resin; 1,3,5-triglycidyl isocyanurate; tris(2,3-epoxypropyl) isocyanurate (and isocyanurate); glycerol diglycidyl ether; trimethylolpropane triglycidyl ether; and the like and combinations thereof. According to further aspects, non-limiting fiber components of the fiber-containing material include carbon fibers, boron fibers, glass fibers, aramid fibers, and the like and combinations thereof.

[0052] In another aspect, the composite material layer includes a fiber-containing epoxy-based composite material.

[0053] In a further aspect, the composite material layer includes a carbon fiber-containing epoxy-based composite material.

[0054] Mold can be alternatively referenced herein and additionally includes mandrel and can be made of metal or non-metal and can be any device capable of supporting a composite material layup (e.g., a layup including any predetermined number of individual composite prepregs, etc.) and imparting or transferring surface properties from a forming surface to a surface of the composite layup surface including, for example, an outer mold line or an inner mold line.

[0055] As Figure 4BAs shown, in the second stage 40B, a spacer layer 46, which may be, for example, a thin flat plate, is oriented near the second surface 44b of the composite substrate. The spacer layer 46 may be a spacer film or spacer sheet in combination with or integrated with a release material film or other release agent. The spacer layer is deposited onto or otherwise oriented onto the second surface 44b of the composite substrate such that the spacer layer 46 is interposed between the second surface 44b of the composite substrate and the top composite layer 48. Figure 4C (as shown in the image).

[0056] exist Figure 4C In the third stage 40C shown, a composite top layer 48 is deposited onto a separator layer 46. A separator layer, in the form of a separator sheet, combined with a release material film or other release agent, is deposited onto the composite top layer 48 and the composite substrate 44, or otherwise disposed or interposed between the composite top layer 48 and the composite substrate 44. The separator layer 46 can be any layer, film, etc., that can serve as an isolation layer or isolation plane for the purpose of facilitating separation of layers after curing (e.g., separating the at least partially cured composite top layer 48' from the at least partially cured composite substrate 44', for example, as... Figure 4D (As shown in the diagram). According to the currently disclosed method, heat or heat and pressure is provided for the purpose of at least partially curing the composite substrate 44 and at least partially curing the composite top layer 48 to form at least partially cured composite substrate 44' and at least partially cured composite top layer 48' (e.g., as shown in the diagram). Figure 4C and Figure 4D (as shown in the image).

[0057] exist Figure 4D In the fourth stage shown, the at least partially cured composite top layer 48' is separated from the at least partially cured composite substrate 44'. Figure 4D As further shown, the at least partially cured composite top layer 48' is removed from the at least partially cured composite substrate 44'. The at least partially cured composite top layer 48' includes a at least partially cured first surface 48a' and a at least partially cured second surface 48b' of the composite top layer. Figure 4D As shown, after at least partial curing of the composite layer, the layers can be separated, and according to one aspect, if the separator layer remains a separate layer, the separator layer is removed. On the other hand, during the period when the separator layer may become indistinguishable from the surrounding layers, but the function of the separator layer is achieved through curing, the at least partially cured composite top layer 48' and the at least partially cured composite substrate 44' can be separated from each other. Although the at least partially cured composite substrate 44' is in Figure 4D and Figure 4EThe at least partially cured composite material substrate 44' is shown as remaining in contact with the mold 42, but alternative manufacturing procedures and stages include removing the at least partially cured composite material substrate 44' from the mold 42 after forming the at least partially cured composite material substrate 44', in accordance with aspects of the present application.

[0058] In Figure 4E A fifth stage 40E is shown in which the at least partially cured composite material substrate 44' is processed to form a processed composite material substrate 44' (including an at least partially cured composite material substrate first face 44a' and an at least partially cured composite material substrate second face 44b'). In accordance with aspects of the present application, and as will be more fully described subsequently, the at least partially cured composite material substrate 44" is processed to form a recess in the at least partially cured composite material substrate 44'. The recess 45 is shown as extending into the substrate from the at least partially cured and processed composite material substrate second face 44b" to a predetermined distance in the composite material substrate thickness. In accordance with further aspects, the predetermined distance can be a predetermined distance that is substantially uniform across the composite material substrate, or the predetermined distance can vary such that the depth of the recess varies.

[0059] Although Figure 4E While not drawn to scale, in accordance with aspects of the present application, the depth of the recess can be any practical depth that recognizes and takes into account competing factors to be weighed, including weight reduction of the substrate by material removal (e.g., processing, etc.) and the stiffness and / or strength of the processed composite material substrate to be maintained. In accordance with aspects of the present application, the above-mentioned competing factors to be weighed can be achieved by processing the recess in the composite material substrate to a depth that represents a distance (e.g., depth distance, etc.) from a surface of about one-half or about two-thirds of the total thickness of the composite material substrate. In accordance with aspects of the present application, a panel can experience a theoretical stiffness loss from an initial unprocessed state to a final processed state. This is a relative stiffness loss, as the weight lost is much more than the stiffness. This results in an increase in the stiffness-to-weight ratio (of the initial unprocessed composite material substrate versus the processed composite material substrate) being achieved by strategic processing in aspects of the present application. For example, depending on the many variables and axes being referenced, the actual stiffness-to-weight ratio can increase by 200% or more by comparing the initial unprocessed composite material substrate stiffness-to-weight ratio to the processed composite material substrate stiffness-to-weight ratio, in accordance with aspects of the present application. This calculation does not even take into account the additional weight reduction achieved in accordance with aspects of the present application from other internal parts like ribs and stringers that can be replaced due to no longer being needed.

[0060] For example, according to aspects of the present application, the composite substrate can have an initial material stiffness (according to ASTM C297) prior to machining and a post-machining material stiffness after machining. According to aspects of the present application, machining the recesses in the composite substrate is performed such that the depth or depth distance of the machined recesses in the composite substrate can be a depth ranging from about one-half to about two-thirds of the overall thickness of the composite substrate. That is, as a non-limiting example, if the overall thickness of the composite substrate is 1.5 inches thick, the depth of the machined recesses in the composite substrate extend from the surface of the composite substrate into the composite substrate a depth of about 0.75 inches to about 1.0 inch. According to aspects of the present application, by adjusting the amount of material removed from the composite substrate and the arrangement or location of the material removed from the composite substrate, the resulting machined composite substrate maintains at least an overall strength and stiffness that is substantially similar to the strength and stiffness of the composite substrate prior to performing this (recess) machining. According to further aspects, and as noted above, depending on the many variables and axes being referenced, the actual stiffness-to-weight ratio can increase by 200% or more according to aspects of the present application before factoring in the elimination of panel weight represented by no longer needed long stringers, ribs, beams, etc.

[0061] When the composite component is made from or otherwise includes the presently disclosed composite substrate, the substrate can be shaped as a large panel for a large structure, including, for example, an aircraft wing assembly. According to aspects of the present application, the machining of the predetermined pattern of recesses machined at predetermined locations and predetermined depths in the composite substrate is controlled such that the composite substrate imparts a stiffening function to the wing assembly in a manner that no longer requires discrete stiffening layers or discrete stiffening components (e.g., stringers, frames, fastener attachment ribs, stringers, frames, etc.) previously found in the wing assembly. According to aspects of the present application, the wing assembly and composite substrate disclosed herein no longer requires the incorporation of the above-mentioned discrete stiffening components or discrete stiffening layers, and in so doing, the weight of the wing assembly is reduced by at least the weight represented by the eliminated stiffening components.

[0062] According to aspects of the present application, a significant amount of composite material is removed from the composite substrate. Removing this composite material greatly reduces the weight of the composite substrate, the composite parts that are built into the composite substrate, the assemblies that include the parts, and the large end item structures that include the assemblies. As a non-limiting example, an exemplary composite panel having dimensions of 72 inches (width) x 720 inches (length) x 1.25 inches (thickness) has a volume of 64,800 cubic inches. According to the presently disclosed method, if a recessed pattern having dimensions of 7 inches (wide) x 22 inches (long) x 1 inch (thick) is removed from the panel and 240 recesses are machined into the panel, the total amount of material removed equals 36,960 cubic inches. Thus, this material removal results in a volume reduction of approximately 57% and a corresponding weight reduction. This weight reduction is significant for such structures that are machined to provide a strengthened structural part (e.g., a wing panel in an aircraft) while no longer requiring additional internal structural support and reinforcement (e.g., stringers, frames, fasteners, etc.). When the composite substrates and parts according to aspects of the present application are incorporated into a vehicle, this weight savings can directly translate into lower fuel costs, increased payload, increased vehicle range, etc. Aspects of the present application also significantly reduce part complexity and labor costs for manufacturing installation, resulting in further operational cost savings.

[0063] Between the steps 40D and 40E (shown in Figure 4D and Figure 4E ) illustrated, aspects of the present application contemplate a machining step of machining recesses 45 in the at least partially cured composite substrate second face 44b', wherein the recesses are formed in the composite substrate in a predetermined thickness and a predetermined pattern, wherein the recesses also each include a predetermined geometric profile. The geometric profile is created by removing a predetermined amount of the composite substrate from the composite substrate to form a three-dimensional recess of a predetermined shape and having a predetermined volume. Even within the pattern itself, the geometric profile of each of the recesses of the predetermined pattern can be the same or can vary, and the individual recesses and the overall pattern can be any predetermined shape, including rectangular, oval, circular, triangular, polygonal, irregular, or combinations thereof.

[0064] Figure 5 is a top view of the machined composite substrate 44" showing a plurality of recesses 45 machined in the substrate and a predetermined pattern 41 of composite material, wherein composite material is removed from the at least partially cured composite substrate second face 44b' of the at least partially cured composite substrate 44' to form the recesses 45 in the now machined composite substrate second face 44b" of the machined composite substrate 44" (see Figure 6A and Figure 6B ).

[0065] For example, material removal from a composite substrate for the purpose of forming a plurality of recesses can typically be performed using various material removal systems (e.g., CNC cutters, lasers, etc.). When the number of recesses is large, and when the total amount of composite material to be removed to form the recesses is large, the typical material removal time can be extremely lengthy. That is, the total time required to form the recesses to a preselected predetermined depth by typical performed cutting, rastering, ablation, etc. processes or systems can take tens of hours or tens of days.

[0066] In contrast, according to aspects of the present application, by implementing the presently disclosed aspects, the rate of removal of the composite material substrate from the recesses is significantly increased, and the time required to form the recesses is significantly reduced. According to aspects of the present application, the composite material substrate is "pre-processed" by infiltrating the composite material substrate with additional detectable material at predetermined locations within the composite material substrate. That is, according to aspects of the present application, the detectable material is introduced or otherwise formed in the composite material substrate during the construction of the composite material substrate at predetermined locations within the thickness of the composite material substrate.

[0067] According to other aspects of the present application, the additional detectable material introduced or formed in the composite material substrate forms a "slip plane," which can form a region within the thickness of the composite material substrate. The slip plane is located within the thickness of the composite material a predetermined distance from the upper surface or second surface of the composite material. The slip plane is also configured to form the "bottom" of the recesses during the recess formation process. According to further aspects, the predetermined distance can be a predetermined distance that is substantially uniform across the composite material substrate, or the predetermined distance can vary such that the depth of the recesses varies.

[0068] According to further aspects, when the perimeter of a preselected region (e.g., a portion of a preselected pattern) is machined to a depth within the thickness of the composite material substrate at which the slip plane exists, the composite material located above the slip plane will be more easily separated from the remainder of the composite material substrate and can be removed from the composite material substrate to form a recess in the composite material substrate.

[0069] According to aspects of the present application, the composite material to be removed from the composite material substrate to form recesses in the composite material substrate can be machined in "chunks" of composite material and removed, rather than being rastered stepwise to remove small amounts of material and create a large amount of airborne particulate matter. Thus, the presently disclosed method saves the recess formation phase (e.g., machining) of the current process performed in the composite material substrate, and greatly reduces: 1) the total cost of processing; 2) the total cost of the machined composite material substrate; 4) the cost of components, assemblies, and larger final structures that are populated with the machined composite material substrate; 5) the processing time; etc.

[0070] The additional detectable material can be configured to have a different porosity or porosity value than the porosity or porosity value of the surrounding composite substrate, for example, by different curing protocols, etc. According to aspects of the present application, when a composite substrate is being layered in a layup on a mold, an additional detectable material having a porosity different than the porosity of the at least partially cured composite substrate can be introduced or formed in the composite substrate. In this regard, a first amount of, for example, prepreg plies, is layered to a first region of a first composite substrate to a predetermined thickness. The composite substrate made from the first amount of prepreg plies is referred to herein equivalently as the composite substrate "first amount" (e.g., the "first amount" of composite material added to or layered onto, for example, a mold) or the composite substrate "first region." When the composite substrate is at least partially cured, the first amount or first region of the composite substrate has a predetermined porosity value such as less than 0.2% or less than 2.0%.

[0071] According to aspects of the present application, an additional detectable material is layered on or otherwise added to or formed in the first region to substantially cover the first region. The term "additional detectable material" is referred to herein equivalently and used interchangeably with the term "second region" or "second region material" or "intermediate layer." The porosity is a result of the materials selected for use and the selected processing protocol, including, for example, curing protocol differences, etc. In aspects of the present application, the "second region material" can be initially selected to be the same material as the material selected for use in the "first region." Additionally, the curing condition differences between the first region and the second region can cause a detectable porosity difference to be formed between the first region material and the second region material. For example, according to aspects of the present application, the second region material can be cured under a heat blanket rather than in a pressurized environment. In view of the lack of pressure when cured, the second region material will exhibit and have a much greater predetermined porosity and porosity value than the predetermined porosity and predetermined porosity value of the first region material. The difference between the porosity value of the second region material and the porosity value of the surrounding composite substrate (e.g., the first region) is significant enough that the difference in porosity values can be detected by non-destructive inspection of the at least partially cured composite substrate by applying an instrument (e.g., an ultrasonic inspection device, an X-ray backscatter inspection device, etc.).

[0072] According to aspects of the present disclosure, the second region material can be applied as a laminated layer and can be a film, such as a fluorinated ethylene propylene (FEP) film having one metallized side. The second region material can also be any material that does not adversely affect the performance of the cured composite substrate. The second region material can change form or can interact with the adjoining composite in the composite substrate. In any aspect, a region is formed that is held in place and is distinguishable according to various different characteristics, where the different characteristics are detectable when the composite substrate is at least partially cured, where preferably the different characteristics can be detected using non-destructive inspection techniques.

[0073] In addition to porosity, the material can also be inspected for its in-plane Young's modulus. According to aspects of the present disclosure, the intermediate material layer can be made of a material having a detectable in-plane Young's modulus value ranging, for example, from about 150 ksi to about 550 ksi, while the surrounding composite substrate in the at least partially cured state can include an in-plane Young's modulus value ranging from about 1200 ksi to 1400 ksi.

[0074] In another aspect, the second region material includes a predetermined pattern, or the second region material is laminated or otherwise applied to the composite substrate in a predetermined pattern. That is, aspects of the present disclosure contemplate applying the second region material or intermediate layer as a film, where the film includes a predetermined pattern on the film, and where the second region material includes regions of the second region material, but not necessarily throughout the film. Alternatively, according to aspects of the present disclosure, the second region material can be applied to the composite substrate via deposition techniques (e.g., spraying, brushing, decal, etc.) for the purpose of creating discontinuous layers of the second region material in a predetermined pattern on the composite substrate according to one aspect. According to further non-limiting aspects, the intermediate layer can include a release material that is substantially non-reactive with the surrounding composite substrate, and can include, for example, a fluorinated ethylene propylene (FEP) film, a polytetrafluoroethylene (PTFE) film, a polyvinyl fluoride (PVF) film, etc.

[0075] For the purposes of the present disclosure, and according to aspects of the present disclosure, release is a characteristic that inhibits adjacent layers from adhering to the substrate on which the layer is applied. Materials such as the presently disclosed second region material and intermediate layer are referred to herein equivalently and interchangeably as "release materials" or materials capable of creating "release" regions.

[0076] According to aspects of the present disclosure, regardless of the form of the deposition pattern or the amount of the second region material deposited, after the second region material has been present or introduced into the composite substrate, a first predetermined thickness of the composite substrate is provided (also referred to as the intermediate layer and in Figure 6AThe predetermined pattern of second region material (e.g., as shown in FIG. 1) is thus positioned to be proximate to or at the location (e.g., place) of the "bottom" of the recess to be machined in the at least partially cured composite material substrate. In other words, the predetermined pattern of second region material is positioned to be proximate to or at the location (e.g., place) of the "bottom" of the recess to be machined in the at least partially cured composite material substrate.

[0077] According to aspects of the present disclosure, an additional amount of composite material substrate is then layered over the second region material to achieve the predetermined thickness. Once the recess is machined in the at least partially cured composite material substrate, the surrounding wall of the machined recess will include the additional amount of composite material substrate deposited onto the second region material, while the bottom of the machined recess will be substantially at the location of the second region material, as described above. Additionally, according to aspects of the present disclosure, the size, geometric profile, and location (e.g., place) of the recess can substantially match the predetermined pattern of the second region material.

[0078] In another aspect, the predetermined pattern can be selectively at least partially cured or activated into an intermediate layer / second region material to form a surface morphology in the resin material within the composite material substrate at the resin material / intermediate layer interface that produces a "slip plane." The production of the "slip plane" (equivalently referred to herein as a "peel layer") is induced at the composite material substrate (a predetermined thickness within the composite material substrate) at the location of the patterned region that is at least partially cured for the purpose of introducing undesirable adhesion at the intermediate layer / second region material interface. According to aspects of the present disclosure, the "bottom" of the recess to be machined in the composite material substrate will be formed by the peel material or peel material layer (e.g., second material region) that is within the composite material substrate thickness at the location of the resin material / intermediate layer (second material region) interface, thus corresponding to the location of the "slip plane."

[0079] Additional aspects of introducing a slip plane into a composite material substrate and forming a heterogeneous composite material substrate include providing an intermediate layer to a first amount or "charge" of layered composite material. According to aspects of the present disclosure, a heterogeneous material refers to the presence of two different materials (in Figure 6A (e.g., as shown in FIG. 1) is thus positioned to be proximate to or at the location (e.g., place) of the "bottom" of the recess to be machined in the at least partially cured composite material substrate. In other words, the predetermined pattern of second region material is positioned to be proximate to or at the location (e.g., place) of the "bottom" of the recess to be machined in the at least partially cured composite material substrate.

[0080] According to a further aspect of the application, to cure the material making up the composite substrate according to a predetermined pattern, a heating device, such as a zoned thermal electric heater or a heating and cooling blanket, can be placed adjacent to the intermediate layer. The zoned heating and cooling blanket can be zoned such that the location of the predetermined patterned areas, e.g., the areas in which the recesses are to be machined, will be heated, while locations outside of the predetermined patterned areas will be cooled. When power is supplied to the heating device, the future locations of the recesses corresponding to the predetermined pattern are heated to at least partially cure the predetermined areas of the composite substrate, while areas outside of or beyond the predetermined patterned areas are not cured. Heat is transferred from the heating device to the composite substrate such that only a few microns of depth in the composite substrate exhibit a predetermined degree of epoxy-amine polymerization. This degree of cure can be achieved by supplying a pulsed power cycle in which heat is added or supplied to the composite substrate in order to prevent the formation of epoxy-amine resin macromolecules that would ultimately cure across the surface of the composite substrate at the intermediate layer / composite substrate interface that would result in poor adhesion of the additional composite layer supplied at the predetermined patterned areas. The areas of poor adhesion form a "slip plane" and a delamination area at the predetermined patterned areas that will become the local bottom of the recesses to be machined in the composite substrate.

[0081] In a further aspect, to form a detectable delamination area or detectable "slip plane" within the composite substrate (and form a heterogeneous composite substrate), an intermediate layer is added to a first amount or first charge of composite material, which is subsequently chemically treated at predetermined patterned areas that closely correspond to the locations in the composite substrate where recesses are to be machined. In one example, a chemical agent can be applied (e.g., sprayed in a spray form from a dedicated device on, for example, a contour tape laying machine (CTLM) head) that preferentially reacts with the amines, epoxides, or catalysts within the predetermined amine-epoxy resin. Additional layers of composite material are then applied to the intermediate layer when the heterogeneous composite substrate is complete prior to machining. The agent promotes a reaction at the intermediate layer / composite interface that forms areas of porosity that are different from the porosity values of the composite material used to form the composite substrate.

[0082] According to the exemplary methods presented herein, and according to aspects of the present application, a local slip plane is formed during the manufacture of the composite substrate such that a discernible and detectable region is formed within the thickness of the composite substrate. From the placement of the interlayer, the approximate region (e.g., location) within the thickness of the machined composite substrate where the slip plane is located can be known. According to aspects of the present application, by non-destructively inspecting the thickness of the composite substrate, such as by determining the porosity of the thickness and determining the location within the thickness of the composite substrate where a change in porosity exists, the region of the slip plane can be determined. That is, according to aspects of the present application, the difference in porosity values (or difference in other perceptible properties) between the interlayer porosity values (e.g., slip plane region porosity values) and the composite porosity values can be accurately determined using, for example, ultrasonic techniques, x-ray backscatter techniques, etc. that are used in conjunction or otherwise feed data to the material removal device. For example, once the location of the interlayer / slip plane region is determined by the inspection process, the determined location is supplied to the material removal device and material is removed from the composite substrate up to the thickness where the slip plane exists. The predetermined location of the recess to be machined is determined and the material removal device removes composite material from the composite substrate around the perimeter of the recess to be machined in the composite substrate. Since the "bottom" of the recess is located in the slip plane, the peeling of the composite material at the slip plane region facilitates the removal of the composite material to form the recess because once the machining of the perimeter has "loosened" or "released" the "block" of composite material that is to be removed from the composite substrate for the purpose of forming the recess in the predetermined pattern in the composite substrate, the composite material can be removed from the recess in large sections or even in substantially the entire piece of composite material (e.g., to form the recess).

[0083] Porosity differences of 0.2% size can be detected. Porosities below 2.0% are generally acceptable. According to aspects of the present application, for plates cured in an autoclave, the porosity is generally less than 0.2% (e.g., indicating no detectable porosity). For thin layers of "second region material" that can be cured via a heating blanket external to the autoclave, the porosity is expected to range from 2.0% to 10.0%. The detection of material porosity and porosity value differences has been discussed herein for the purpose of determining the location of the peeling region within the composite substrate (e.g., the location of the interlayer or region interface where the peeling region occurs within the thickness of the composite substrate).

[0084] According to aspects of the present invention, various non-destructive inspection techniques can be used to determine characteristics other than porosity. For example, to determine the location of the thin layer of second region material, techniques, systems, and apparatuses for measuring the in-plane Young's modulus of a material can be used. In a non-limiting example, aspects of the present invention contemplate that the interlayer or second region is made of a material having an in-plane Young's modulus value in the range of about 150 ksi to about 550 ksi, while the surrounding composite substrate has an in-plane Young's modulus value in the range of about 1200 ksi to about 1400 ksi.

[0085] In Figure 6A and Figure 6B improved current aspects of removing material from a composite substrate are shown. Figure 6A is a partial cross-sectional view of the at least partially cured composite substrate 44'. As Figure 6A shown in, the material removal device 62 is shown in the form of a CNC cutting machine, although current aspects contemplate the use of any material removal or cutting device, including, for example, lasers, drill bits, etc. According to aspects of the present invention, the material removal device 62 can be in communication with a controller 64, which in turn can be in communication with a processor 66 that can be programmed to communicate signals to the controller 64, which can control the material removal device 62 for the purpose of cutting, for example, in the at least partially cured composite second face 44b' to a predetermined distance or predetermined thickness to form a plurality of recesses 45 formed in the at least partially cured composite substrate in a predetermined recess pattern, according to programmed values inputted at processor input 68, for example, and controlled by the controller 64. In alternative aspects, the material removal device 62 is in communication with the processor 66, and the processor includes an integrated controller 67. As Figure 6A shown in, the interlayer 47 includes a second region material that is detected and forms a release region according to aspects of the present invention, which can be a release pattern region that facilitates the removal of composite material to form recesses and resides at the "bottom" of the recesses. Although not shown in, aspects of the present invention also contemplate the incorporation of non-destructive inspection equipment (e.g., ultrasonic probes, ultrasonic receivers, forward ray backscatter equipment, etc.) in communication with the controller and / or processor for the purpose of scanning the composite substrate, determining the location of the slip plane (based on, for example, the sensed material porosity differences mentioned above), sending signals to the controller and / or processor, and adjusting the material removal process so that as a result, a predetermined thickness of recess pattern is formed in the composite substrate machined corresponding to the location of the slip plane / interlayer region is predetermined. Figure 6A

[0086] Figure 6B ​A top plan view of a machined composite substrate 44" is shown having recesses 45 of a predetermined thickness machined in the substrate in a predetermined pattern, where each recess 45 is formed in or is to be formed in the substrate such that, in accordance with aspects of the present application, the recesses 45 have a substantially uniform predetermined size. Although not shown in Figure 6A and Figure 6B , the recesses can each have different sizes and the recesses can each have the same or different geometric profiles. That is, although not shown, in accordance with further aspects, the recesses can be formed according to the predetermined pattern such that the size of the recesses varies with respect to one another or the size of at least one of the recesses varies with respect to the remaining recesses.

[0087] As further shown in Figure 6B , recess perimeters 45a of the recesses 45 are machined in the machined composite substrate 44" such that composite "plugs" 44c are released from the machined composite substrate 44" and can be removed at this time substantially in one piece. The machined composite substrate 44" also represents the heterogeneous material listed as 43.

[0088] In accordance with further aspects not shown, when the composite removal forming the recesses is accomplished using a CNC cutting device and, for example, ultrasound is used as the non-destructive inspection procedure method, the drill used to perform the cutting can include an ultrasonic horn and a detector, as the mechanical vibrations caused by the milling can occur in a different frequency range than the ultrasound. The ultrasound is positioned and directed to detect the location of the intermediate layer. In further aspects, the ultrasound device will detect the location of the intermediate layer, which will serve as the "bottom" of the recess to be removed from the composite substrate. The ultrasound device can be located at a predetermined specific distance from the material removal device, such that, for example, the drill can be positioned based on the relative movement of the ultrasound head for detecting the intermediate material (e.g., "slip plane" region, etc.), which in some cases can be zero.

[0089] As mentioned above, when the intermediate layer is provided as a thin layer (including curing the predetermined pattern into the intermediate layer (e.g., curing performed outside of an autoclave)), the curing of such an intermediate layer can result in a higher porosity or a greater porosity value in the thin intermediate layer (which can be detected by, for example, ultrasound), as the porosity of the cured intermediate layer or the cured region of the intermediate layer will be perceptibly different from the porosity value of the surrounding composite substrate. In accordance with aspects of the present application, the drill can be configured to respond to the detected change / difference in porosity value and can extend in the composite thickness to a depth of the location of the intermediate layer, by an integrated controller or when in communication with a controller.

[0090] For example, and in accordance with aspects of the present application, the presently disclosed processing advantages are significant. For example, typical material removal techniques for forming recesses or recess patterns in composite materials include back and forth rastering of a 1 / 2 inch drill bit that is set to drill approximately 1 inch in depth for a total thickness of the composite substrate of approximately 1.5 inches. If a recess of 7 inches in width is desired, the drill bit will be rastered approximately 9 times back and forth. If the length of each recess is 22 inches, then for a total cutting distance of 396 inches of drill bit movement for each recess, the rastering will constitute a total cutting length of approximately 9 inches x 2 x 22 inches. At a drill bit movement rate of approximately 30 inches / minute, the composite material removal rate for each recess is estimated to be approximately 12.8 minutes to remove 12 cubic inches of composite material to form the intended recess.

[0091] In comparison to the above-described typical rastering / processing rates and times, in accordance with aspects of the present application, the same amount of material is removed to form each similarly sized recess but only 2 x 7 inches (width) + 2 x 22 inches (length) or 58 inches of drill bit movement is drilled around the perimeter of the recess to achieve a similar depth, even using a 1 / 4 inch drill bit. This results in a reduction in material removal time for each recess from 12.8 minutes to 2 minutes (assuming the same drill bit movement rate of approximately 30 inches / minute). Additionally, because only the perimeter of the recess is drilled and the composite substrate "plug" or "block" is removed to form the recess, significantly smaller particulate material is formed, thus improving the safety of the work place with respect to atmospheric particulate content. This can be of concern when the composite material being removed to form the recesses includes carbon fiber epoxy amine resin. The significant reduction or substantial elimination of the formation of carbon fiber epoxy amine resin dust and particulate enhances the safety of the work place and eliminates an amount of particulate material that is generated, collected and / or disposed of.

[0092] Additionally, given that a large composite part can have as many as 240 recesses (e.g., in a wing size aircraft wing wall panel), the time savings provided by aspects of the present application are significant. For example, in the example given above, over 43 hours of time will be saved, or approximately 84% of the processing time is reduced, by applying the method of aspects of the present application as compared to removing the composite material using the typical rastering method. Forming parts in accordance with aspects of the present application and methods of manufacturing the same result in significant cost and time savings as compared to typical parts and typical methods of manufacturing the same, for example, composite wing parts and assemblies.

[0093] Additionally, since aspects of the present application significantly reduce the amount of drilling or other machining required, the costs associated with replacing, repairing, maintaining, etc. the machinery and machinery components (e.g., drill bits, etc.) and the power required to operate (e.g., lasers, etc.) and power the machinery are also greatly reduced. Additionally, aspects of the present application allow for the use of smaller drill bits to drill the recessed perimeters (e.g., as compared to the larger drill bits typically used for rastering), resulting in further cost savings since smaller (e.g., ¼ inch) drill bits are typically less expensive than larger (½ inch or greater) drill bits.

[0094] Figure 7 , Figure 8 and Figure 9 are perspective views of machined composite material substrates in accordance with aspects of the present application, wherein the recesses are shown having various geometric profiles. As shown in Figure 7 , machined composite material substrate 44" includes machined composite material substrate second surface 44b" in which a pattern of recesses 45 (having recessed perimeters 45a) of a predetermined thickness are machined for the purpose of removing a predetermined amount of substrate material from the substrate. As shown in Figure 7 , although in accordance with aspects of the present application the recesses exhibit an elliptical geometric profile, any predetermined geometric profile can be machined in the substrate to form a predetermined recess pattern having any desired geometric profile.

[0095] For example, as shown in Figure 8 , machined composite material substrate 44" includes machined composite material substrate second surface 44b" in which a pattern of recesses 45 (having recessed perimeters 45a) of a predetermined thickness are machined for the purpose of removing a predetermined amount of substrate material from the substrate. As shown in Figure 8 , although in accordance with aspects of the present application the recesses exhibit a plurality of triangular geometric profiles, any predetermined geometric profile can be machined in the substrate to form a predetermined recess pattern having any desired geometric profile.

[0096] By way of further example, as shown in Figure 9 , machined composite material substrate 44" includes machined composite material substrate second surface 44b" in which a pattern of recesses 45 (having recessed perimeters 45a) of a predetermined thickness are machined for the purpose of removing a predetermined amount of substrate material from the substrate. As shown in Figure 9 , although in accordance with aspects of the present application the recesses exhibit a rectangular geometric profile (e.g., a "square" form of rectangle), any predetermined geometric profile can be machined in the substrate to form a predetermined recess pattern having any desired geometric profile.

[0097] According to aspects of the invention, including, for example Figure 7 , Figure 8 and Figure 9 The aspects shown herein allow for the fabrication of recesses machined into at least partially cured composite substrates according to any predetermined pattern, and each recess can be machined to independently have any predetermined geometric distribution, such that the machined component can be tailored to achieve predetermined strength, stiffness, etc., to meet the performance requirements of a component manufactured according to aspects of the invention. The ability to tailor the strength and stiffness along regions of large components such as aircraft, spacecraft, rotorcraft, etc., can facilitate the design and manufacture of large structures to address new issues concerning aerodynamic response, including, for example, flutter.

[0098] Figure 10A , Figure 10B and Figure 11 This is a flowchart outlining another aspect of the method according to this disclosure. (e.g.) Figure 10A The diagram illustrates a method 100A according to an aspect of the invention, which includes orienting a plurality of composite material layers 102 onto a tool to form a composite material substrate. According to an aspect of the invention, the composite material substrate may include a composite material substrate thickness, and the tool may be a forming tool that may include a processing surface, wherein the composite material substrate further includes a first surface and a second surface, and wherein the first surface is disposed close to the processing surface. Figure 10A The method 100 outlined herein also illustrates introducing a predetermined pattern region 104 at a predetermined location within the composite substrate in a composite substrate, at least partially curing the composite substrate 106, and removing 108 a predetermined amount of at least partially cured composite material from the at least partially cured composite substrate using a material removal device to form a recess in the location of the predetermined pattern region. According to aspects of the invention, and as disclosed above, the material removal device may be a CNC machine, a laser, a drill bit or other mechanical cutting device, or a combination thereof.

[0099] like Figure 10B The diagram illustrates a method 100B according to an aspect of the invention, which includes orienting a plurality of composite material layers 102 onto a tool to form a composite material substrate. According to an aspect of the invention, the composite material substrate may include a composite material substrate thickness, and the tool may be a forming tool that may include a processing surface, wherein the composite material substrate further includes a first surface and a second surface, and wherein the first surface is disposed close to the processing surface. Figure 10B The method 100B outlined in the text also illustrates introducing a predetermined patterned region 104 at a predetermined location within the composite substrate, and at least partially curing the composite substrate 106. (As...)Figure 10B As shown in the method 100B, the method 100B includes at least partially curing 107 the predetermined pattern into a portion of the composite material substrate. Figure 10B The method 100B, as shown in the method 100B, further includes removing 108, with a material removal device, a predetermined amount of the at least partially cured composite material from the at least partially cured composite material substrate to form a recess in the location of the predetermined pattern area. According to aspects of the present disclosure, and as disclosed above, the material removal device can be a CNC machine, a laser, a drill bit or other mechanical cutting device, or the like, or combinations thereof.

[0100] As Figure 10C As shown in the method 100C, the method 100C includes orienting 102 a plurality of composite material layers onto a tool to form a composite material substrate. According to aspects of the present disclosure, the composite material substrate can include a composite material substrate thickness, and the tool can be a forming tool that can include a machined surface, wherein the composite material substrate further includes a composite material substrate first surface and a composite material substrate second surface, and wherein the composite material substrate first surface is disposed proximate the machined surface. Figure 10C The method 100C, as outlined in the method 100C, further shows introducing 104 a predetermined pattern area at a predetermined location within the composite material substrate by chemically treating 105 a region of the composite material substrate used to form a second region to form a chemically treated second region, and at least partially curing 106 the composite material substrate. Figure 10C The method 100C, as shown in the method 100C, further includes removing 108, with a material removal device, a predetermined amount of the at least partially cured composite material from the at least partially cured composite material substrate to form a recess in the location of the predetermined pattern area. According to aspects of the present disclosure, and as disclosed above, the material removal device can be a CNC machine, a laser, a drill bit or other mechanical cutting device, or the like, or combinations thereof.

[0101] A non-limiting list of chemical agents contemplated for use in reacting with the epoxy-amine reaction in the composite material substrate to form a debonding region within the composite material substrate can include, for example, methanol, carboxylic acids, formaldehyde, formic acid, carbon, and the like. These chemical agents can react with amine groups at room temperature, and in some cases, the predetermined reaction can require the presence of a metal as a photocatalyst. While not being bound by a particular theory, it is believed that these chemical agents will deplete substantially all of the local amine monomers before the epoxy-amine reaction occurs (at elevated temperatures), as no strong macrocyclics are formed within the entire region without available amine groups, which will result in the formation of a slip plane. Additionally, aromatic amines and aliphatic amines, which are typically present in "five minute" epoxies, can react with epoxy groups at room temperature and substantially deplete the local epoxy groups before the epoxy-amine reaction occurs (at elevated temperatures), and for similar reasons as those described above, will result in the formation of a slip plane.

[0102] As Figure 11 As shown in FIGS. 1-3 and in accordance with aspects of the present disclosure, a method 200 is outlined that includes providing 202 a heterogeneous composite substrate having a composite substrate (e.g., a first region material) and an intermediate layer (e.g., a second region material), and at least partially curing 204 a predetermined region of the composite substrate. The method 200 further includes orienting 206 a material removal device proximate the composite substrate, and determining 208 a location of the composite substrate / intermediate layer interface (e.g., the first region material / second region material interface), followed by removing 210a a predetermined amount of the at least partially cured composite substrate, and forming 212 a predetermined recess pattern in the composite substrate. As with the methods 100A, 100B, 100C and method 200 described above, and in accordance with aspects of the present disclosure, the material removal device can be a CNC machine, a laser, a drill bit or other mechanical cutting device, or the like, or combinations thereof. The intermediate layer can be introduced into the composite substrate to form a heterogeneous composite material when the heterogeneous composite substrate is laminated, where the intermediate layer is introduced into the heterogeneous composite substrate at a predetermined distance. In accordance with further aspects, the predetermined distance at which the intermediate layer is located can be a predetermined distance that is substantially uniform across the heterogeneous composite substrate, or the predetermined distance can vary such that the depth of the recess (the location of the sliding surface, and in turn the location of the "bottom" of the recess) is different for different recesses.

[0103] Figure 12 A method 300 in accordance with aspects of the present disclosure is outlined that includes providing 202 a heterogeneous composite substrate having a composite substrate (e.g., a first region material) and an intermediate layer (e.g., a second region material), and at least partially curing 204 a predetermined region of the composite substrate. The method 300 further includes orienting a material removal device proximate the composite substrate, and determining 208 a location of the composite substrate / intermediate layer interface (e.g., the first region material / second region material interface). The outlined method 300 further includes activating 302 the material removal device, and directing 304 the material removal device around a perimeter of a predetermined pattern region of the composite substrate corresponding to a predetermined pattern region introduced into the composite substrate by the intermediate layer. The method 300 further includes removing 306 a predetermined amount of the composite substrate from the perimeter of the predetermined pattern region, and removing 308 the composite material within the perimeter to form a recess. As with the methods 100A, 100B, 100C and method 200 described above, and in accordance with aspects of the present disclosure, the material removal device of the method 300 can be a CNC device, a laser, a drill bit or other mechanical cutting device, or the like, or combinations thereof.

[0104] Further, the present disclosure includes examples in accordance with the following clauses:

[0105] Clause 1. A method (100) (200) comprising the steps of:

[0106] orienting (102) a plurality of composite material layers onto a tool to form a composite material substrate, the composite material substrate having a composite material substrate thickness, the tool comprising a tool surface, and the composite material substrate comprising a composite material substrate first surface and a composite material substrate second surface, the composite material substrate first surface being disposed proximate the tool surface;

[0107] introducing (104) a predetermined pattern region to the composite material substrate, the predetermined pattern region being configured to be introduced to the composite material substrate at a location within the composite material substrate thickness at a predetermined distance from the composite material substrate second surface;

[0108] at least partially curing (106) the composite material substrate to form an amount of at least partially cured composite material substrate, the at least partially cured composite material substrate being configured to extend from the composite material substrate second surface a predetermined distance into the composite material substrate to form a predetermined amount of at least partially cured composite material substrate; and

[0109] removing (108) at least a portion of the predetermined amount of at least partially cured composite material substrate at the predetermined distance from the composite material second surface to form a predetermined recessed pattern in the at least partially cured composite material substrate, the predetermined recessed pattern substantially matching the predetermined pattern region.

[0110] Clause 2. The method of clause 1, the composite material layers comprising fiber- containing epoxy-based composite material.

[0111] Clause 3. The method of clause 1 or 2, the composite material layers comprising carbon fiber-containing epoxy-based composite material.

[0112] Clause 4. The method of clause 1, 2, or 3, introducing a predetermined pattern region to the composite material substrate further comprising the steps of:

[0113] at least partially curing (204) the predetermined pattern region in the composite material substrate.

[0114] Clause 5. The method of any of clauses 1-4, introducing a predetermined pattern region to the composite material substrate further comprising the steps of:

[0115] chemically treating (105) the predetermined pattern region into the composite material substrate.

[0116] Clause 6. The method of any of clauses 1-5, introducing the predetermined pattern region to the composite substrate further comprises the steps of:

[0117] stacking an intermediate layer in the composite substrate, the intermediate layer being stacked in the composite substrate at the predetermined distance from the second surface of the composite substrate,

[0118] and the intermediate layer comprising the predetermined pattern region.

[0119] Clause 7. The method of clause 4, further comprising the steps of:

[0120] orienting a heat blanket proximate the second surface of the composite substrate, the heat blanket comprising a plurality of heating zones configured to at least partially cure the composite substrate to a predetermined cured thickness, and the plurality of heating zones configured to at least partially cure the composite substrate to form the at least partially cured predetermined pattern region into the composite substrate.

[0121] Clause 8. The method of clause 5, further comprising the steps of:

[0122] chemically processing the predetermined pattern region into the composite substrate by applying a chemical agent at a predetermined location within the composite substrate thickness during manufacture of the composite substrate to form the predetermined pattern region.

[0123] Clause 9. The method of clause 6, the intermediate layer comprising a material that is substantially non-reactive with the composite substrate.

[0124] Clause 10. The method of clause 6, the intermediate layer comprising a material having a range of transverse Young’s modulus values from about 150 ksi to about 550 ksi; and

[0125] wherein, after at least partial curing, the composite layer has a range of transverse Young’s modulus values from about 1200 ksi to about 1400 ksi.

[0126] Clause 11. The method of clause 6, the intermediate layer being configured to form a predetermined peel pattern region.

[0127] Clause 12. The method of clause 7, the at least partially cured predetermined pattern region comprising a different porosity than a porosity of the composite substrate.

[0128] Clause 13. The method of clause 8, the chemical agent being configured to form a predetermined pattern region comprising a different porosity than a porosity of the composite substrate.

[0129] Clause 14. A method (300), the method (100) comprising the steps of:

[0130] providing (202) a heterogeneous composite substrate comprising a heterogeneous composite substrate surface, the heterogeneous composite substrate further comprising a predetermined composite substrate thickness, the heterogeneous composite substrate further comprising:

[0131] a first region of composite substrate comprising a first porosity;

[0132] a second region within the first region of composite substrate, the second region comprising a second porosity, the second region being disposed at a predetermined distance from the heterogeneous composite substrate surface within the predetermined composite substrate thickness;

[0133] at least partially solidifying (204) a predetermined region of the first region of composite substrate of the heterogeneous composite substrate, the predetermined region of the first region of composite substrate being configured to extend from the heterogeneous composite substrate surface to the second region to form a predetermined amount of at least partially solidified first region of composite substrate;

[0134] orienting (206) a material removal device proximate the heterogeneous composite substrate surface;

[0135] determining (208) a location of a first region of composite substrate / second region interface in the heterogeneous composite substrate; and

[0136] removing (210) the predetermined amount of at least partially solidified first region of composite substrate from the heterogeneous composite substrate;

[0137] the predetermined amount of at least partially solidified first region of composite substrate extends from the heterogeneous composite substrate surface to the first region of composite material / second region interface.

[0138] Clause 15. The method (300) of clause 14, further comprising the steps of:

[0139] activating (302) the material removal device; and

[0140] removing (306) the predetermined amount of first region of composite substrate from the heterogeneous composite substrate;

[0141] the predetermined amount of first region of composite substrate extends from the heterogeneous composite substrate surface to the first region of composite material / second region interface.

[0142] Clause 16. The method of clauses 14 or 15, the predetermined distance from the heterogeneous composite substrate surface comprises a predetermined distance that is substantially uniform across the heterogeneous composite substrate.

[0143] Clause 17. The method of clauses 14, 15, or 16, the material removal device comprises a laser.

[0144] Clause 18. The method of any of clauses 14 to 17, the material removal device comprises a CNC device.

[0145] Clause 19. The method of any of clauses 14 to 18, wherein the material removal device is in communication with a controller, the controller is further in communication with an ultrasonic receiver.

[0146] Clause 20. The method of any of clauses 14 to 19, the composite substrate first region comprises uncured composite material, the heterogeneous composite material comprises a fiber- containing epoxy-based composite material.

[0147] Clause 21. The method of any of clauses 14 to 20, the composite substrate first region comprises at least one of: a partially cured fiber-reinforced epoxy-based composite material or a fully cured fiber-containing epoxy-based composite material.

[0148] Clause 22. The method of any of clauses 14 to 21, the second region comprises a chemically treated composite material second region.

[0149] Clause 23. The method of any of clauses 14 to 22, the second region comprises a release material.

[0150] Clause 24. The method of clause 23, the second region material comprises at least one of: a fluorinated ethylene propylene-containing film, a polytetrafluoroethylene-containing film, a polyvinyl fluoride-containing film; and combinations of the above.

[0151] Clause 25. A composite laminate, the composite laminate comprising:

[0152] a composite substrate (12) (44) comprising:

[0153] a composite substrate first surface (21) (40a) and a composite substrate second surface (22) (40b), the composite substrate is configured to include a plurality of depressions (14) (45) extending from the composite substrate surface a predetermined distance into the composite substrate, the depressions comprising a predetermined size;

[0154] an intermediate layer (47) disposed within the composite substrate at a predetermined depth, the intermediate layer;

[0155] wherein the recess is bounded by surrounding composite substrate and the intermediate layer; and

[0156] wherein the intermediate layer comprises a release region.

[0157] Clause 26. The composite laminate of Clause 25, wherein the composite substrate comprises:

[0158] a fiber-containing epoxy-based composite.

[0159] Clause 27. The composite laminate of Clause 25 or 26, wherein the composite substrate comprises a carbon fiber-containing epoxy-based composite.

[0160] Clause 28. The composite laminate of Clause 25, 26, or 27, wherein the intermediate layer comprises at least one of: fluorinated ethylene propylene, polytetrafluoroethylene, polyvinyl fluoride; and combinations thereof.

[0161] Clause 29. A vehicle (30) comprising the composite laminate of any one of Clauses 25-28.

[0162] Clause 30. A wing assembly (10) comprising the composite laminate of any one of Clauses 25-29.

[0163] Clause 31. A wing assembly inner skin (12) comprising the composite laminate of any one of Clauses 25-30.

[0164] Clause 32. The vehicle of Clause 29, wherein the vehicle comprises at least one of: a manned aerial vehicle; an unmanned aerial vehicle; a manned space vehicle; an unmanned space vehicle; a manned rotorcraft; an unmanned rotorcraft; a manned land vehicle; an unmanned ground vehicle; a manned water-borne watercraft; an unmanned water-borne watercraft; a manned underwater watercraft; an unmanned underwater watercraft; and combinations thereof.

[0165] Clause 33. The wing assembly of Clause 31, further comprising:

[0166] a wing assembly outer skin disposed over the wing assembly inner skin.

[0167] Of course, the presently disclosed aspects can be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the application. The present aspects are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

Claims

1. A method for manufacturing a composite material substrate having a predetermined recessed pattern, the method comprising the following steps: Multiple composite material layers are oriented onto a tool to form a composite material substrate, the composite material substrate having a composite material substrate thickness, the tool including a processing surface, and the composite material substrate including a first surface and a second surface, the first surface being positioned close to the processing surface; A predetermined patterned region is introduced into the composite material substrate, the predetermined patterned region being configured to be introduced into the composite material substrate at a predetermined distance from the second surface of the composite material substrate at a position within the thickness of the composite material substrate. The composite material substrate is at least partially cured to form a certain amount of at least partially cured composite material substrate, the at least partially cured composite material substrate being configured to extend from the second surface of the composite material substrate by the predetermined distance into the composite material substrate to form a predetermined amount of at least partially cured composite material substrate; as well as At least a portion of the at least partially cured composite substrate is removed at a predetermined distance from the second surface of the composite material to form the predetermined recessed pattern in the at least partially cured composite substrate, the predetermined recessed pattern matching the predetermined pattern area.

2. The method according to claim 1, wherein the composite material layer comprises a fiber-containing epoxy composite material.

3. The method according to claim 1 or 2, wherein the composite material layer comprises an epoxy-based composite material containing carbon fibers.

4. The method according to claim 1 or 2, further comprising the step of introducing a predetermined patterned region into the composite material substrate: The predetermined patterned area is at least partially cured into the composite material substrate.

5. The method according to claim 1 or 2, further comprising the step of introducing a predetermined patterned region into the composite material substrate: The predetermined patterned area is chemically processed into the composite material substrate.

6. The method according to claim 1 or 2, further comprising the step of introducing a predetermined patterned region into the composite material substrate: An intermediate layer is stacked in the composite material substrate at a predetermined distance from the second surface of the composite material substrate, and the intermediate layer includes the predetermined pattern area.

7. The method according to claim 4, further comprising the following step: The heating blanket is oriented close to the second surface of the composite substrate, the heating blanket including a plurality of heating areas configured to at least partially cure the composite substrate to a predetermined curing thickness, and the plurality of heating areas configured to at least partially cure the composite substrate to form a predetermined patterned area at least partially cured into the composite substrate.

8. The method according to claim 5, further comprising the following step: The predetermined pattern region is chemically treated into the composite substrate by applying a chemical reagent at a predetermined location within the thickness of the composite substrate during the manufacture of the composite substrate to form the predetermined pattern region.

9. The method of claim 6, wherein the intermediate layer comprises a material that does not react with the composite substrate.

10. The method of claim 6, wherein the intermediate layer comprises a material with a transverse Young's modulus ranging from about 150 kSi to about 550 kSi; and in, After at least partial curing, the transverse Young's modulus of the composite layer ranges from about 1200 ksi to about 1400 ksi.

11. The method of claim 6, wherein the intermediate layer is configured to form a predetermined peel pattern region.

12. The method of claim 7, wherein the at least partially cured predetermined patterned region comprises a porosity different from that of the composite substrate.

13. The method of claim 8, wherein the chemical reagent is configured to form the predetermined patterned region, the predetermined patterned region comprising a porosity different from that of the composite substrate.

14. A method for manufacturing a heterogeneous composite substrate with recesses, the method comprising the steps of: A heterogeneous composite material substrate is provided, including a surface of a heterogeneous composite material substrate. The heterogeneous composite material substrate further includes a predetermined composite material substrate thickness, and the heterogeneous composite material substrate further includes: A first region of a composite material substrate, comprising a first porosity; The second region is located within the first region of the composite material substrate. The second region includes a second porosity and is located at a predetermined distance from the surface of the heterogeneous composite material substrate within the predetermined thickness of the composite material substrate. At least partially solidify a predetermined region of the first region of the composite material substrate, wherein the predetermined region of the first region of the composite material substrate is configured to extend from the surface of the heterogeneous composite material substrate to the second region, to form a predetermined amount of at least partially solidified first region composite material substrate; Orient the material removal device close to the surface of the heterogeneous composite substrate; Determine the location of the interface between the first region of the heterogeneous composite substrate and the second region; and A predetermined amount of at least partially cured first region composite material substrate is removed from the heterogeneous composite material substrate, the predetermined amount of at least partially cured first region composite material substrate extending from the surface of the heterogeneous composite material substrate to the first region composite material / second region interface; Start the material removal device; and A predetermined amount of a first region of the composite material substrate is removed from the heterogeneous composite material substrate to form a recess, wherein the predetermined amount of the first region of the composite material substrate extends from the surface of the heterogeneous composite material substrate to the interface between the first region composite material substrate and the second region.

15. The method of claim 14, wherein the predetermined distance from the surface of the heterogeneous composite substrate includes a predetermined distance consistent throughout the heterogeneous composite substrate.

16. The method of claim 14, wherein the material removal apparatus comprises a laser.

17. The method of claim 14, wherein the material removal device comprises a CNC device.

18. The method according to claim 14, wherein, The material removal device communicates with a controller, which in turn communicates with an ultrasonic receiver.

19. The method of claim 14, wherein the first region of the composite material substrate comprises an uncured composite material, and the heterogeneous composite material comprises a fiber-containing epoxy composite material.

20. The method of claim 14, wherein the first region of the composite substrate comprises at least one of the following: a partially cured fiber-reinforced epoxy composite material, and a fully cured fiber-containing epoxy composite material.

21. The method of claim 14, wherein the second region comprises a chemically treated composite material second region.

22. The method of claim 14, wherein the second region comprises a stripping material.

23. The method of claim 22, wherein the second region material comprises at least one of the following: a membrane containing fluorinated ethylene propylene, a membrane containing polytetrafluoroethylene, a membrane containing polyvinyl fluoride, and a combination thereof.

24. A composite layered compound comprising: A composite material substrate includes: a first surface of a composite material substrate and a second surface of a composite material substrate, the composite material substrate being configured to include a plurality of recesses extending a predetermined distance from the surface of the composite material substrate into the composite material substrate, the recesses having a predetermined size; An intermediate layer is disposed at a predetermined depth within the composite material substrate; The recess is bounded by the surrounding composite substrate and the intermediate layer; and The intermediate layer includes a stripping region.

25. The composite layer according to claim 24, wherein, The composite material substrate includes: Epoxy composites containing fibers.

26. The composite layer according to claim 24 or 25, wherein, The composite material substrate includes an epoxy-based composite material containing carbon fibers.

27. The composite layer according to claim 24 or 25, wherein, The intermediate layer includes at least one of the following: fluorinated ethylene propylene, polytetrafluoroethylene, polyvinyl fluoride, and combinations thereof.

28. A vehicle comprising the composite laminate according to claim 24 or 25.

29. The vehicle according to claim 28, wherein, The vehicle includes at least one of the following: Manned aircraft; unmanned aircraft; manned spacecraft; unmanned spacecraft; manned rotorcraft; unmanned rotorcraft; manned land vehicle; unmanned ground vehicle; manned water transport vehicle; unmanned water transport vehicle; manned underwater transport vehicle; unmanned underwater transport vehicle; and combinations thereof.

30. A wing assembly comprising the composite laminate according to claim 24 or 25.

31. The wing assembly of claim 30, further comprising: The outer skin of the wing assembly is mounted on the inner skin of the wing assembly.

32. An inner skin for a wing assembly, the inner skin comprising the composite laminate according to claim 24 or 25.

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