Composite joint inspection

Abstract

The present invention provides composite joint inspection.SOLUTION: A composite joint inspection system and methods of use and formation are presented. The composite joint inspection system comprises a cavity formed by at least two composite components, a composite filler within the cavity, and a fiber optic cable extending through the cavity extending from at least one of a first end of the cavity or a second end of the cavity. The fiber optic cable is in contact with the composite filler.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates generally to non-destructive testing, and more particularly to testing composite joints. [Background technology]

[0002] Composite structures can be fabricated by joining two or more members together. In some cases, the area of ​​the joint between the members may have one or more gaps that can reduce the strength of the joint. To strengthen the joint, the gaps are filled with a filler, which may also be called a corner filler, composite filler, fillet, or noodle.

[0003] Some composite airframe components, such as skin stringers and web-to-flange attachments of beams and channels, include these structural elements called "noodles." Noodles, or corner fillers, are used to fill corner bends in curved composite laminate structures. Noodles are composed of composites with a different orientation than the primary laminate structure. Noodles are located in areas that may be undesirably difficult or inconsistent to inspect by typical nondestructive methods. Typical nondestructive inspections using ultrasound are expensive, time-consuming, and inconsistent in inspecting curvatures and noodles due to the complex geometries and locations. Summary of the Invention [Problem to be solved by the invention]

[0004] It would therefore be desirable to have a method and apparatus that takes into account at least some of the problems discussed above, as well as other possible problems. It would be desirable to develop a technique for non-destructively inspecting the interior noodle regions of curved composite laminate structures. [Means for solving the problem]

[0005] One embodiment of the present disclosure provides a composite joint inspection system that includes: a void formed by at least two composite components; a composite filler within the void; and a fiber optic cable extending through the void extending from at least one of a first end of the void and a second end of the void, the fiber optic cable in contact with the composite filler.

[0006] One embodiment of the present disclosure provides an aircraft comprising a composite joint having an integrated strain detector, the integrated strain detector comprising: a first composite component, a second composite component, a composite filler positioned in a void between the first composite component and the second composite component, and a fiber optic cable extending through the void extending from at least one of a first end of the void and a second end of the void, the fiber optic cable contacting the composite filler.

[0007] One embodiment of the present disclosure provides a method for inspecting a composite splice. Light waves are sent through a fiber optic cable extending through a gap in the composite splice, the fiber optic cable extending from at least one of a first end of the gap and a second end of the gap, and the fiber optic cable contacts a composite filler in the gap. A reflectance index of light received from the fiber optic cable is measured. Based on the reflectance index, it is determined whether strain has affected the composite splice.

[0008] One embodiment of the present disclosure provides a method for forming a composite joint, wherein a composite filler is placed in a void between at least two composite components, a fiber optic cable is placed in the void such that the fiber optic cable contacts the composite filler, and the composite filler and the at least two composite components are infused with resin to form a composite joint having an integrated strain detector.

[0009] Another embodiment of the present disclosure provides a composite joint inspection system that includes at least two composite components joined together at a composite joint, a composite filler within the composite joint, and a fiber optic cable embedded between layers of a composite component of the at least two composite components, the fiber optic cable extending along the joint and extending from at least one of a first end of the composite component and a second end of the composite component.

[0010] Yet another embodiment of the present disclosure provides a method for inspecting a composite structure. Light waves are transmitted through a fiber optic cable extending through the composite structure, the fiber optic cable extending from at least one of a first end of the composite structure and a second end of the composite structure, the fiber optic cable contacting the composite structure. A reflectance index of light received from the fiber optic cable is measured. The measured reflectance index is compared to a baseline reading.

[0011] The features and functions may be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings.

[0012] The novel features believed characteristic of the exemplary embodiments are set forth in the appended claims. However, the exemplary embodiments, as well as their preferred modes of use, further objects and features, will best be understood by reference to the following detailed description of exemplary embodiments of the present disclosure, when considered in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an illustration of an aircraft in accordance with an illustrative embodiment; [Figure 2] FIG. 1 is a block diagram of a manufacturing environment in accordance with an illustrative embodiment. [Figure 3] FIG. 1 is an illustration of a composite bond inspection system in accordance with an illustrative embodiment; [Figure 4]1 is a flowchart of a method for inspecting a composite joint in accordance with an illustrative embodiment. [Figure 5] 1 is a flowchart of a method for forming a composite joint in accordance with an illustrative embodiment. [Figure 6] 1 is a flowchart of a method for inspecting a composite structure in accordance with an illustrative embodiment. [Figure 7] FIG. 1 is an illustration of an aircraft manufacturing and service method in the form of a block diagram in accordance with an illustrative embodiment; [Figure 8] FIG. 1 is an illustration of an aircraft in the form of a block diagram in which an illustrative embodiment may be implemented; DETAILED DESCRIPTION OF THE INVENTION

[0014] The illustrative examples recognize and take into account one or more considerations: The illustrative examples recognize and take into account that inconsistent results are obtained when inspecting monolithic noodles using conventional non-destructive testing techniques.

[0015] The illustrative examples recognize and take into account that current non-destructive testing practice includes the use of a swept ultrasonic probe shaped to the same radius as the integral joint radius. The illustrative examples recognize and take into account that noodles do not have parallel front and back surfaces. The illustrative examples recognize and take into account that a noodle, in simplified form, is triangular in cross section. The illustrative examples recognize and take into account that due to the non-parallel geometry, reflected and attenuated wave signals may not be strongly detected, leading to inconsistent results.

[0016] The illustrative examples recognize and take into account that there are access limitations when a physical probe is swept along an area to be inspected. The illustrative examples recognize and take into account that in traditional ultrasonic inspection, probe shapes are customized to fit the radius of the scan plane. The illustrative examples recognize and take into account that different probes are used at different radii. The illustrative examples recognize and take into account that multiple probes are used in a sweep radius plane of ever-changing dimensions. The illustrative examples recognize and take into account that no probe shape will fit exactly into a sweep radius plane.

[0017] The illustrative examples recognize and take into account that some composite noodles use "chopped fibers" that significantly degrade the signal reflected by the ultrasonic probe. The illustrative examples recognize and take into account that chopped fibers may prevent ultrasonic inspection from successfully inspecting these new monolithic structures.

[0018] The illustrative examples recognize and take into account that other non-destructive testing (NDI) techniques include X-ray CT and acoustic emission. The illustrative examples recognize and take into account that in the case of X-ray CT, the scanning equipment is expensive and too large for the intended use area of ​​the composite noodle. The illustrative examples recognize and take into account that acoustic emission (e.g., PZT) relies on detection of reflected waves. The illustrative examples recognize and take into account that acoustic emission (e.g., PZT) is also susceptible to insufficient signal collection for the reasons discussed above.

[0019] Referring now to Figure 1, an illustration of an aircraft is shown in accordance with an illustrative embodiment. Aircraft 100 has wing 102 and wing 104 attached to body 106. Aircraft 100 includes engine 108 attached to wing 102 and engine 110 attached to wing 104.

[0020] The body 106 has a tail section 112. A horizontal stabilizer 114, a horizontal stabilizer 116, and a vertical stabilizer 118 are attached to the tail section 112 of the body 106.

[0021] Aircraft 100 is an example of an aircraft that may have composite joints inspected using the illustrative example method. Aircraft 100 is an example of an aircraft that may have composite joints formed using the illustrative example method. An illustrative example composite joint may be present on aircraft 100.

[0022] With reference now to Figure 2, an illustration of a block diagram of a manufacturing environment is shown in accordance with an illustrative embodiment. Composite joint inspection system 201 may be used with aircraft 100 in Figure 1. Composite joint inspection system 201 may be formed in manufacturing environment 200. Composite joint inspection system 201 may be utilized outside of manufacturing environment 200 to inspect composite joints 207.

[0023] Composite joint 207 is a component of platform 242. Platform 242 can take many different forms. For example, platform 242 can be selected from a group including a mobile platform, a fixed platform, a land structure, an underwater structure, a space structure, an aircraft, a commercial aircraft, a rotorcraft, a tiltrotor aircraft, a tilt-wing aircraft, a vertical take-off and landing aircraft, an electric vertical take-off and landing vehicle, a personal air vehicle, a tanker aircraft, a surface vessel, a tank, a personnel carrier, a train, a spacecraft, a space station, a satellite, a submarine, an automobile, a power plant, a bridge, a dam, a house, a manufacturing facility, a building, a robot, a robotic arm, a crane, and other suitable types of platforms. In some illustrative examples, platform 242 can be an aircraft 244.

[0024] Composite joint inspection system 201 comprises a void 208 formed by at least two composite components, a composite filler 210 within void 208, and a fiber optic cable 216 extending through void 208 extending from at least one of a first end 212 of void 208 and a second end 214 of the void. Fiber optic cable 216 is in contact with composite filler 210. In this illustrative example, the at least two composite components comprise a first composite component 204 and a second composite component 206.

[0025] In some illustrative examples, fiber optic cables 216 are embedded within composite filler 210. In some of these illustrative examples, composite filler 210 is laid up within the layup with fiber optic cables 216. In some of these illustrative examples, composite filler 210 is extruded within composite filler 210 with fiber optic cables 216.

[0026] In some illustrative examples, fiber optic cable 216 is in contact with an outer surface of one of the at least two composite components and composite filler 210. In some illustrative examples, fiber optic cable 216 is in contact with outer surface 237 of first composite component 204 and composite filler 210. In some illustrative examples, fiber optic cable 216 is in contact with outer surface 237 of second composite component 206 and composite filler 210.

[0027] Fiber optic cable 216 is one of multiple fiber optic cables 215. Multiple fiber optic cables 215 comprises one or more fiber optic cables in contact with composite filler 210. In some illustrative examples, multiple fiber optic cables 215 comprises a plurality of fiber optic cables distributed throughout composite filler 210. In some illustrative examples, multiple fiber optic cables 215 comprises a plurality of fiber optic cables spread throughout cross-section 232 of composite filler 210. Spreading multiple fiber optic cables throughout cross-section 232 of composite filler 210 enables strain to be detected at various cross-sectional locations, including an interface between composite filler 210 and at least one of composite components, first composite component 204, and second composite component 206.

[0028] In some illustrative examples, composite joint inspection system 201 includes second fiber optic cable 217 extending through void 208 extending from at least one of first end 212 of void 208 and second end 214 of void 208. Second fiber optic cable 217 is positioned within composite filler 210.

[0029] In this illustrative example, inspection system 218 is connected to fiber optic cable 216 to inspect composite filler 210. In some illustrative examples, inspection system 218 may be temporarily connected to fiber optic cable 216 to inspect composite filler 210 during a set time, such as during manufacturing or maintenance. In some illustrative examples, inspection system 218 may be continuously connected to fiber optic cable 216 to inspect composite filler 210 while platform 242 is in operation.

[0030] Inspection system 218 includes a data acquisition system 226 and an optical emitter 228. The optical emitter is configured to transmit light waves 230 into fiber optic cable 216. In some illustrative examples, composite splice inspection system 201 further includes optical emitter 228 connected to fiber optic cable 216.

[0031] Data acquisition system 226 is configured to receive a response from fiber optic cable 216. Data acquisition system 226 may also be referred to as a detector. In some illustrative examples, composite joint inspection system 201 further includes data acquisition system 226 connected to the fiber optic cable.

[0032] In some illustrative examples, the light emitter 228 and the detector may be at the same end of the fiber optic cable 216. In some illustrative examples, both the light emitter 228 and the detector may be at both ends of the fiber optic cable 216. In some illustrative examples of the inspection system 218, light may be emitted from both ends so that the location of the strain change can be output.

[0033] To inspect composite splice 207, light waves 230 are sent through fiber optic cable 216 that extends through void 208 of composite splice 207. In some illustrative examples, fiber optic cable 216 extends from first end 212 of void 208 to second end 214 of void 208. Fiber optic cable 216 is in contact with composite filler 210 in void 208.

[0034] A reflectance index 224 of light received from fiber optic cable 216 is measured. In some illustrative examples, based on reflectance index 224, it is determined whether strain has affected composite splice 207.

[0035] In some illustrative examples, it is determined whether the reflectance index 224 has changed from the baseline 222. In some illustrative examples, the reflectance index 224 and the baseline 222 are compared by the computer system 220. In some illustrative examples, the reflectance index 224 is analyzed by a collaborative data analyzer.

[0036] In some demonstrative examples, the collaborative data analyzer may be located on computer system 220 and may be implemented in software, hardware, firmware, or a combination thereof. If software is used, the operations performed by the collaborative data analyzer may be implemented in program instructions configured to execute on hardware, such as a processor unit. If firmware is used, the operations performed by the collaborative data analyzer may be implemented in program instructions and data stored in persistent memory for execution on a processor unit. If hardware is used, the hardware may include circuitry operative to perform the operations in the collaborative data analyzer.

[0037] In illustrative examples, the hardware may take the form of at least one selected from a circuit system, an integrated circuit, an application specific integrated circuit (ASIC), a programmable logic device, or some other suitable type of hardware configured to perform a number of operations. Using a programmable logic device, a device may be configured to perform a number of operations. The device may be later reconfigured or may be permanently configured to perform a number of operations. Programmable logic devices include, for example, programmable logic arrays, programmable array logic, field programmable logic arrays, field programmable gate arrays, and other suitable hardware devices.

[0038] The computer system 220 is a physical hardware system and includes one or more data processing systems. When multiple data processing systems are present in the computer system, the data processing systems communicate with each other using a communication medium. The communication medium may be a network. The data processing systems may be selected from at least one of a computer, a server computer, a tablet computer, and some other suitable data processing system.

[0039] The computer system 220 may include multiple processor units capable of executing program instructions that implement the processes for the collaborative data analyzer in the illustrative example, in other words, the program instructions are computer-readable program instructions.

[0040] In some illustrative examples, Brillouin optical time-domain analysis can be utilized to determine whether mismatches exist in composite filler 210. Acoustic waves are generated by injecting two counter-propagating light waves, such as light wave 230, with a frequency difference equal to the Brillouin shift. If one of the beams is a short light pulse whose position is determined by time-of-flight, local variations in strain can be measured along fiber optic cable 216.

[0041] In some illustrative examples, composite joint 207 is part of aircraft 244. In some illustrative examples, aircraft 244 comprises composite joint 207 with integrated strain sensors. Composite joint 207 with integrated strain sensors comprises first composite component 204, second composite component 206, and composite filler 210 positioned in void 208 between first composite component 204 and second composite component 206. The composite joint further comprises fiber optic cable 216 extending through void 208 and extending from at least one of first end 212 of void 208 and second end 214 of void 208. Fiber optic cable 216 is in contact with composite filler 210.

[0042] In some illustrative examples, cross section 232 of composite filler 210 is triangular shaped 234. Composite bond inspection system 201 provides accurate inspection of composite filler 210 having triangular shaped cross section 232. Conventional ultrasonic inspection techniques are too difficult and / or too time consuming and / or inconsistent to inspect triangular shaped cross section 232.

[0043] In some illustrative examples, the composite filler 210 comprises chopped fiber 236. The composite bond inspection system 201 provides accurate inspection of the composite filler 210 with chopped fiber 236. The chopped fiber 236 reduces the signal reflected by the ultrasonic probe, making conventional ultrasonic inspection of the composite filler 210 with chopped fiber 236 undesirably difficult or inconsistent.

[0044] In some illustrative examples, at least one of fiber optic cable 216 and second fiber optic cable 217 may be present in one composite component of composite structure 202. In some illustrative examples, fiber optic cable 216 may be present in first composite component 204. In some illustrative examples, second fiber optic cable 217 may be present in second composite component 206.

[0045] In some illustrative examples, composite joint inspection system 201 includes at least two composite components joined together at a composite joint 207, a composite filler 210 within composite joint 207, and a fiber optic cable 216 embedded between layers of a first composite component 204 of the at least two composite components. Fiber optic cable 216 extends along composite joint 207 and extends from at least one of a first end 250 of first composite component 204 and a second end 252 of first composite component 204. In some illustrative examples, fiber optic cable 216 is embedded within ten composite plies of composite joint 207.

[0046] In some illustrative examples, composite joint inspection system 201 further comprises a second fiber optic cable 217 embedded within composite filler 210 .

[0047] In some illustrative examples, composite joint inspection system 201 further includes a second fiber optic cable 217 embedded between layers of a second composite component 206 of the at least two composite components. In these illustrative examples, second fiber optic cable 217 extends along composite joint 207 and extends from at least one of a first end 246 of second composite component 206 and a second end 248 of second composite component 206.

[0048] The illustration of manufacturing environment 200 in FIG. 2 is not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented. Other components in addition to or in place of the illustrated components may be used. Some components may be unnecessary. Also, the blocks are presented to illustrate some functional components. One or more of these blocks may be combined, divided, or combined and divided into different blocks when implemented in an illustrative embodiment.

[0049] For example, in some illustrative examples, multiple fiber optic cables 215 comprises three or more fiber optic cables. In some illustrative examples, multiple fiber optic cables may be placed across the entire cross-section of void 208. In some illustrative examples, adding multiple fiber optic cables may be beneficial to detect inconsistencies at the interface between composite filler 210 and composite components of composite structure 202. As another example, cross-section 232 of composite filler 210 is a shape other than a generally triangular shape.

[0050] 3, an illustration of a composite bond inspection system 300 is shown in accordance with an illustrative embodiment. Composite bond inspection system 300 is a physical implementation of composite bond inspection system 201 of FIG.

[0051] In this illustrative example, composite structure 302 includes first composite component 306, second composite component 308, and third composite component 310. Void 312 is formed between first composite component 306, second composite component 308, and third composite component 310. Composite filler 313 resides within void 312.

[0052] Composite joint inspection system 300 includes a void 312 formed by at least two composite components, a composite filler 313 within void 312, and a fiber optic cable 314 extending through void 312 extending from at least one of a first end 320 of void 312 and a second end 322 of void 312. Fiber optic cable 314 is in contact with composite filler 313. In this illustrative example, fiber optic cable 314 is embedded within composite filler 313. In this illustrative example, fiber optic cable 314 is centered within composite filler 313. In some illustrative examples, fiber optic cable 314 is embedded within composite filler 313 at different locations across a cross section of composite filler 313.

[0053] As shown, composite bond inspection system 300 further includes a second fiber optic cable 324 extending through void 312 extending from at least one of first end 320 of void 312 and second end 322 of void 312. Second fiber optic cable 324 is positioned within composite filler 313.

[0054] In this illustrative example, second fiber optic cable 324 is in contact with an outer surface of one of the at least two composite components and composite filler 313. In this illustrative example, second fiber optic cable 324 is in contact with an outer surface of second composite component 308 and composite filler 313.

[0055] As shown, inspection system 304 is connected to fiber optic cable 314. Inspection system 304 is connected to fiber optic cable 314 by connector 316 and connector 318. Inspection system 304 includes an optical emitter and a detector. The detector or data acquisition system is configured to receive signals from fiber optic cable 314.

[0056] Inspection system 304 transmits light waves through fiber optic cable 314. To inspect composite splice 303, the light waves are transmitted through fiber optic cable 314, which extends through cavity 312 of composite splice 303. Fiber optic cable 314 extends from a first end of cavity 312 to a second end of cavity 312. Fiber optic cable 314 contacts composite filler 313 in cavity 312.

[0057] The reflectance index of light received from the fiber optic cable is measured. Based on the reflectance index, it is determined whether strain has affected the composite splice. In some illustrative examples, determining whether strain has affected the composite splice 303 includes determining whether the reflectance index has changed from a baseline. In some illustrative examples, the inspection system 304 performs the determination regarding whether the reflectance index has changed from a baseline.

[0058] While fiber optic cable 314 and second fiber optic cable 324 are shown within void 312, in other illustrative examples, at least one fiber optic cable is present in at least one of first composite component 306, second composite component 308, and third composite component 310. In some illustrative examples, the fiber optic cable is present between layers of first composite component 306 along composite joint 303. In some illustrative examples, the fiber optic cable is present between layers of first composite component 306 parallel to void 312. In some illustrative examples, the fiber optic cable is present between layers of second composite component 308 along composite joint 303. In some illustrative examples, the fiber optic cable is present between layers of second composite component 308 parallel to void 312. In some illustrative examples, the fiber optic cable is present between layers of third composite component 310 along composite joint 303. In some illustrative examples, the fiber optic cable is present between layers of third composite component 310 parallel to void 312.

[0059] Referring now to Figure 4, an illustration of a flowchart of a method for inspecting a composite joint in accordance with an illustrative embodiment is depicted. Method 400 may be used to inspect a composite joint of aircraft 100 in Figure 1. Method 400 may be used to inspect composite joint 207 in Figure 2. Method 400 may be implemented using composite joint inspection system 201 in Figure 2. Method 400 may be implemented to inspect composite joint 303 in Figure 3. Method 400 may be implemented using composite joint inspection system 300 in Figure 3.

[0060] Method 400 sends a light wave through a fiber optic cable extending through an air gap of a composite splice, the optical cable extending from at least one of a first end of the air gap and a second end of the air gap, where the fiber optic cable contacts a composite filler in the air gap (operation 402). Method 400 measures the reflectance index of light received from the fiber optic cable (operation 404). Method 400 compares the measured reflectance index to a baseline reading (operation 406). Method 400 then ends.

[0061] In some illustrative examples, method 400 places a composite filler in the void between the at least two composite components (OPERATION 408). In some illustrative examples, method 400 places a fiber optic cable in the void such that the fiber optic cable contacts the composite filler (OPERATION 410). In some illustrative examples, the fiber optic cable is placed in the void before placing the composite filler in the void. In some illustrative examples, the fiber optic cable is positioned within the composite filler. In these illustrative examples, the fiber optic cable is placed in the void simultaneously with placing the composite filler in the void.

[0062] In some illustrative examples, method 400 injects resin into the composite filler and the at least two composite components to form a composite joint with an integrated strain detector (operation 412). In some illustrative examples, method 400 injects resin into the composite filler while the composite filler is in contact with the fiber optic cable.

[0063] In some illustrative examples, method 400 attaches an optical emitter to the fiber optic cable (OPERATION 414). In some illustrative examples, method 400 attaches a data acquisition system to the fiber optic cable (OPERATION 416). In some illustrative examples, the optical emitter and the data acquisition system are part of an inspection system connected to the fiber optic cable.

[0064] In some illustrative examples, method 400 determines whether distortion has affected the composite joint based on comparing the measured reflectance index to a baseline reading (operation 418). In some illustrative examples, the determination is made by an inspection system comprising a data acquisition system and an optical emitter. In some other illustrative examples, the reflectance index is provided to a computer system separate from the inspection system for analysis.

[0065] Referring now to Figure 5, an illustration of a flowchart of a method for forming a composite joint is depicted in accordance with an illustrative embodiment. Method 500 may be implemented to manufacture components of aircraft 100 in Figure 1. Method 500 may be implemented to manufacture composite joint 207 in Figure 2. Method 500 may be implemented to manufacture composite joint 303 in Figure 3.

[0066] The method 500 places a composite filler in a void between at least two composite components (operation 502). The method 500 places a fiber optic cable in the void such that the fiber optic cable contacts the composite filler (operation 504). The method 500 injects a resin into the composite filler and the at least two composite components to form a composite joint having an integrated strain detector (operation 506). The method 500 then ends.

[0067] In some demonstrative examples, method 500 extrudes a fiber optic cable into the composite filler, and disposing the fiber optic cable in the void is performed by disposing the composite filler in the void (Operation 508). In some demonstrative examples, disposing the fiber optic cable in the void includes contacting the fiber optic cable with a first composite component of the at least two composite components, and disposing the composite filler in the void includes contacting the composite filler with the fiber optic cable (Operation 510).

[0068] In some illustrative examples, method 500 attaches an optical emitter to the fiber optic cable (OPERATION 512). In some illustrative examples, method 500 attaches a data acquisition system to the fiber optic cable (OPERATION 514). In some illustrative examples, the optical emitter and the data acquisition system are part of an inspection system connected to the fiber optic cable.

[0069] With reference now to Figure 6, an illustration of a flowchart of a method for inspecting a composite structure is depicted in accordance with an illustrative embodiment. Method 600 may be used to inspect the composite structure of aircraft 100 in Figure 1. Method 600 may be used to inspect composite structure 202 in Figure 2. Method 600 may be implemented to inspect composite structure 302 in Figure 3.

[0070] Method 600 sends light waves through a fiber optic cable extending through a composite structure, the fiber optic cable extending from at least one of a first end of the composite structure and a second end of the composite structure, the fiber optic cable contacting the composite structure (operation 602). Method 600 measures the reflectance index of light received from the fiber optic cable (operation 604). Method 600 compares the measured reflectance index to a baseline reading (operation 606).

[0071] In some illustrative examples, method 600 embeds fiber optic cables in composite components of the composite structure within ten plies of a composite joint of the composite structure (operation 608). In some illustrative examples, method 600 injects resin into the composite structure to form a composite structure with integrated strain detectors (operation 610).

[0072] In some demonstrative examples, method 600 attaches an optical emitter to the fiber optic cable (OPERATION 612). In some demonstrative examples, method 600 attaches a data acquisition system to the fiber optic cable (OPERATION 614).

[0073] In some illustrative examples, method 600 determines whether distortion has affected the composite structure based on comparing the measured reflectance index to a baseline reading (operation 616). In some illustrative examples, the determination is made by an inspection system comprising a data acquisition system and an optical emitter. In some other illustrative examples, the reflectance index is provided to a computer system separate from the inspection system for analysis.

[0074] As used herein, the phrase "at least one of," when used in conjunction with a list of items, means that various combinations of one or more of the listed items may be used, and that only one of each item in the list may be required. For example, "at least one of item A, item B, or item C" may include, but is not limited to, item A, item A and item B, or item B. This example may also include item A, item B, and item C, or item B and item C. Of course, any combination of these items may be present. In other examples, "at least one of" may be, for example, but is not limited to, two item A, one item B, and ten item C, or four item B and seven item C, or any other suitable combination. An item may be a specific object, thing, or category. In other words, at least one of means that any combination and number of items may be used from the list, but not all of the items in the list are required.

[0075] As used herein, "plurality," when used in reference to an item, means one or more items.

[0076] The flowcharts and block diagrams in the different depicted embodiments illustrate the architecture, functionality, and operation of some possible implementations of apparatuses and methods in the illustrative embodiments. In this regard, each block in the flowcharts or block diagrams may represent at least one of a module, a segment, a function, or a portion of an operation or step.

[0077] In some alternative implementations of the exemplary embodiments, one or more functions noted in the blocks may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially concurrently, or may sometimes be executed in the reverse order, depending on the functionality involved. Also, other blocks may be added in addition to the illustrated blocks of a flowchart or block diagram. Some blocks may be optional. For example, operations 408 through 418 may be optional. As another example, operations 508 through 514 may be optional. As another example, operations 608 through 616 may be optional.

[0078] An exemplary embodiment of the present disclosure may be described in the context of aircraft manufacturing and service method 700 shown in Figure 7 and aircraft 800 shown in Figure 8. Referring initially to Figure 7, an illustration of an aircraft manufacturing and service method in block diagram form is depicted in accordance with an exemplary embodiment. During pre-production, aircraft manufacturing and service method 700 may include specification and design 702 and material procurement 704 of aircraft 800 in Figure 8.

[0079] During production, component and subassembly manufacturing 706 and system integration 708 of aircraft 800 occurs. Aircraft 800 may then undergo certification and delivery 710 to be in service 712. While in service 712 by a customer, aircraft 800 is scheduled for routine maintenance and service 714, which may include modification, reconfiguration, refurbishment, or other maintenance and service.

[0080] Each of the processes in aircraft manufacturing and service method 700 may be performed or carried out by a system integrator, a third party, and / or an operator. In these examples, the operator may be a customer. For purposes of this description, a system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors, a third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers, and an operator may be an airline, a leasing company, the military, a service provider, etc.

[0081] Referring now to Figure 8, an illustration of an aircraft in block diagram form is depicted in which an illustrative embodiment may be implemented. In this example, aircraft 800 is produced by aircraft manufacturing and service method 700 in Figure 7 and may include an airframe 802 having a number of systems 804 and an interior 806. Example systems 804 include one or more of a propulsion system 808, an electrical system 810, a hydraulic system 812, and an environmental system 814. Any number of other systems may also be included.

[0082] Apparatus and methods embodied herein may be employed during at least one of the stages of aircraft manufacturing and service method 700. One or more illustrative embodiments may be manufactured or used during at least one of component and subassembly manufacturing 706, system integration 708, in-service 712, and maintenance and service 714 in Figure 7.

[0083] An illustrative example provides an inspection technique that is a) non-destructive, b) compact, c) easy to install without additional design effort, d) inexpensive, and e) independent of any wave emission techniques through composite materials. In an illustrative example, at least one optical fiber strand is embedded or bonded along the span of the noodle. Misalignment of the noodle can then be determined by changes in the fiber optic cable signal. The changes in the signal received from the fiber optic cable are associated with misalignment or other changes in the noodle.

[0084] The illustrative example provides a different method of detecting noodle misalignment compared to previous processes. The illustrative example sends light waves through a fiber optic cable to measure the optical reflectance index and determine if there is a change from a "baseline" reading. If a change is detected, the change indicates that the system is distorted, and a significantly high distortion reading / spike or drop in the signal indicates that a misalignment has occurred. In the illustrative example, the fiber optic cable is integrated into the platform structure as a flyaway component, as opposed to relying solely on scanning equipment on the ground. By avoiding the use of inspection equipment that reflects / refracts sound waves off of non-homogeneous materials (i.e., noodles), inconsistent results can be avoided.

[0085] An illustrative example uses light passing through at least one fiber optic cable to detect misalignments in integral noodles for resin-infused aircraft parts. An illustrative example detects noodle misalignments by detecting strain in the embedded fiber optic cable rather than directly detecting misalignments in the noodle itself. An illustrative example does not require proprietary equipment or tooling due to variations in noodle geometry. An illustrative example is a one size fits all solution to composite noodle inspection.

[0086] The illustrative examples provide improved methods for inspecting integral structural noodles. The illustrative examples can be used as both passive and active forms of inspection in composite joints. The illustrative examples can be used as both passive and active forms of inspection in aircraft structures.

[0087] The description of different exemplary embodiments is presented for purposes of illustration and description and is not intended to be exhaustive or limited to the disclosed forms of the embodiments. Many modifications and variations will be apparent to those skilled in the art. Furthermore, different exemplary embodiments may provide different forms compared to other exemplary embodiments. The selected one or more embodiments have been chosen and described to best explain the principles and practical applications of the embodiments, and to enable those skilled in the art to understand the present disclosure for various embodiments with various modifications suitable for the particular use contemplated.

[0088] [Additional note 1] a void (208, 312) formed by at least two composite components (204, 206, 306, 308); a composite filler (210, 313) in the void (208, 312); an optical fiber cable (216, 314) extending through the gap (208, 312) extending from at least one of a first end (212, 320) of the gap (208, 312) and a second end (214, 322) of the gap (208, 312); Equipped with The fiber optic cable (216, 314) contacts the composite filler (210, 313), a composite splice inspection system (218, 304). [Additional note 2] 2. A composite joint inspection system (218, 304) as described in claim 1, wherein the optical fiber cable (216, 314) is embedded within the composite filler material (210, 313). [Additional note 3] A composite joint inspection system (218, 304) as described in Appendix 1, wherein the optical fiber cable (216, 314) is in contact with the outer surface (237) of at least one of the composite components (204, 206, 306, 308) and the composite filler (210, 313). [Additional note 4] a second optical fiber cable (217, 324) extending through the gap (208, 312) from at least one of the first end (212, 320) of the gap (208, 312) and the second end (214, 322) of the gap (208, 312); 2. A composite splice inspection system (218, 304) as described in claim 1, wherein the second optical fiber cable (217, 324) is positioned within the composite filler (210, 313). [Additional note 5] 2. The composite joint inspection system (218, 304) of claim 1, further comprising an optical emitter (228) connected to the optical fiber cable (216, 314). [Additional note 6] 6. The composite joint inspection system (218, 304) of claim 5, further comprising a data acquisition system (226) connected to the fiber optic cable (216, 314). [Additional note 7] a composite joint (207, 303) having an integrated strain detector; The composite joint is a first composite component (204, 306); a second composite component (206, 308); a composite filler (210, 313) positioned in a void (208, 312) between the first composite component (204, 306) and the second composite component (206, 308); an optical fiber cable (216, 314) extending through the gap (208, 312) extending from at least one of a first end (212, 320) of the gap (208, 312) and a second end (214, 322) of the gap (208, 312); Equipped with The optical fiber cable (216, 314) is in contact with the composite filler (210, 313), the aircraft (100, 244, 700). [Additional note 8] 8. The aircraft (100, 244, 700) according to claim 7, wherein the optical fiber cable (216, 314) is embedded within the composite filler (210, 313). [Additional note 9] 8. The aircraft (100, 244, 700) of claim 7, wherein the optical fiber cable (216, 314) is in contact with a surface (237) of the first composite component (204, 306) and the composite filler (210, 313). [Additional Note 10] a second optical fiber cable (217, 324) extending through the gap (208, 312) extending from at least one of the first end (212, 320) of the gap (208, 312) and the second end (214, 322) of the gap (208, 312); 8. The aircraft (100, 244, 700) of claim 7, wherein the second optical fiber cable (217, 324) is positioned within the composite filler (210, 313). [Additional Note 11] 8. The aircraft (100, 244, 700) of claim 7, further comprising an optical emitter (228) connected to the first end (212, 320) of the optical fiber cable (216, 314). [Additional Note 12] 12. The aircraft (100, 244, 700) of claim 11, further comprising a data acquisition system (226) connected to the second end (214, 322) of the fiber optic cable (216, 314). [Additional Note 13] A method (400) for inspecting a composite joint (207, 303), comprising: sending (402) a light wave (230) through a fiber optic cable (216, 314) extending through a gap (208, 312) of the composite joint (207, 303), the fiber optic cable (216, 314) extending from at least one of a first end (212, 320) of the gap (208, 312) and a second end (214, 322) of the gap (208, 312), the fiber optic cable (216, 314) contacting a composite filler (210, 313) in the gap (208, 312); measuring (404) the reflectance index (224) of light received from said fiber optic cable (216, 314); comparing (406) the measured reflectance index (224) with a baseline (222) reading; A method (400) comprising: [Additional Note 14] 14. The method (400) of claim 13, further comprising a step (418) of determining whether distortion has affected the composite joint (207, 303) based on the step of comparing the measured reflectance index (224) with a reading of the reference line (222). [Additional Note 15] attaching (414) a light emitter (228) to the fiber optic cable (216, 314); Attaching (416) a data acquisition system (226) to the fiber optic cable (216, 314); The method (400) according to Appendix 13, further comprising: [Additional Note 16] placing (408) the composite filler (210, 313) in the gap (208, 312) between at least two composite components (204, 206, 306, 308); placing (410) the fiber optic cable (216, 314) in the gap (208, 312) such that the fiber optic cable (216, 314) contacts the composite filler (210, 313); The method (400) according to Appendix 13, further comprising: [Additional Note 17] 17. The method (400) of claim 16, further comprising the step (412) of injecting resin into the composite filler (210, 313) and the two composite components (204, 206, 306, 308) to form the composite joint (207, 303) having an integrated strain detector. [Additional Note 18] A method (500) of forming a composite joint (207, 303), comprising: placing (502) a composite filler (210, 313) in a void (208, 312) between at least two composite components (204, 206, 306, 308); placing (504) the fiber optic cable (216, 314) in the gap (208, 312) such that the fiber optic cable (216, 314) contacts the composite filler (210, 313); injecting (506) a resin into the composite filler (210, 313) and at least two of the composite components (204, 206, 306, 308) to form the composite joint (207, 303) having an integrated strain detector; A method (500) comprising: [Additional Note 19] further comprising the step of extruding (508) the optical fiber cable (216, 314) into the composite filler (210, 313); A method (500) according to claim 18, wherein the step of placing the optical fiber cable (216, 314) in the gap (208, 312) is performed by placing the composite filler (210, 313) in the gap (208, 312). [Additional Note 20] placing (510) the fiber optic cable (216, 314) in the gap (208, 312) includes contacting the fiber optic cable (216, 314) with a first composite component (204, 306) of the at least two composite components (204, 206, 306, 308); The method (500) of claim 18, wherein the step of placing the composite filler (210, 313) in the void (208, 312) includes a step of contacting the composite filler (210, 313) with the optical fiber cable (216, 314). [Additional Note 21] attaching (512) a light emitter (228) to the fiber optic cable (216, 314); Attaching (514) a data acquisition system (226) to the fiber optic cable (216, 314); The method (500) according to Appendix 18, further comprising: [Additional Note 22] at least two composite components (204, 206, 306, 308) joined together at composite joints (207, 303); a composite filler (210, 313) within the composite joint (207, 303); a fiber optic cable (216) embedded between layers of the composite component (204) of at least two of said composite components (204, 206, 306, 308); Equipped with A composite joint inspection system (218, 304), wherein the fiber optic cable (216) extends along the composite joint and extends from at least one of a first end (250) of the composite component (204) and a second end (252) of the composite component (204). [Additional Note 23] 23. A composite joint inspection system (218, 304) as described in claim 22, further comprising a second optical fiber cable (217) embedded within the composite filler (210, 313). [Additional note 24] 23. A composite joint inspection system (218, 304) as described in claim 22, wherein the optical fiber cable (216) is embedded within ten composite plies of the composite joint (207, 303). [Additional note 25] a second fiber optic cable (217) embedded between layers of a second composite component (206) of the at least two composite components (204, 206, 306, 308); A composite joint inspection system (218, 304) as described in Appendix 22, wherein the second optical fiber cable (217) extends along the composite joint (207, 303) and extends from at least one of a first end (246) of the second composite component (206) and a second end (248) of the second composite component (206). [Additional note 26] A method (600) for inspecting a composite structure (202, 302), comprising: sending (602) light waves through a fiber optic cable (216) extending through a composite structure (202, 302), the fiber optic cable (216) extending from at least one of a first end of the composite structure (202, 302) and a second end of the composite structure (202, 302), the fiber optic cable (216) contacting the composite structure (202, 302); measuring (604) the reflectance index (224) of light received from said fiber optic cable (216); comparing (606) the measured reflectance index (224) with a baseline (222) reading; A method (600) comprising: [Additional note 27] 27. The method (600) of claim 26, further comprising a step (616) of determining whether distortion has affected the composite structure (202, 302) based on the step of comparing the measured reflectance index (224) with a reading of the reference line (222). [Additional note 28] attaching (612) a light emitter (228) to the fiber optic cable (216); Attaching (614) a data acquisition system (226) to the fiber optic cable (216); The method (600) according to Supplementary Item 26, further comprising: [Additional note 29] The method (600) of claim 26 further comprises a step (608) of embedding the optical fiber cable (216) in composite components (204, 206, 306, 308, 310) of the composite structure (202, 302) within ten plies of a composite joint (207, 303) of the composite structure (202, 302). [Additional note 30] 27. The method (600) of claim 26, further comprising the step (610) of injecting resin into the composite structure (202, 302) to form the composite structure (202, 302) having an integrated strain detector. [Explanation of symbols]

[0089] 100 aircraft, 102 wing, 104 wing, 106 body, 108 engine, 110 engine, 112 tail section, 114 horizontal stabilizer, 116 horizontal stabilizer, 118 vertical stabilizer, 200 manufacturing environment, 201 composite joint inspection system, 202 composite structure, 204 first composite component, 206 second composite component, 207 composite joint, 208 void, 210 composite filler, 212 first end, 214 second end, 215 multiple fiber optic cables, 216 fiber optic cable, 217 second fiber optic cable, 218 inspection system / composite joint inspection system, 220 computer system, 222 reference line, 224 reflectance index, 226 data acquisition system, 228 light emitter, 230 light wave, 232 Cross section, 234 Triangle, 236 Chopped fiber, 237 Outer surface, 238 Resin infusion, 240 Resin, 242 Platform, 244 Aircraft, 246 First end, 248 Second end, 250 First end, 252 Second end, 300 Composite joint inspection system, 302 Composite structure, 303 Composite joint, 304 Inspection system / Composite joint inspection system, 306 First composite component, 308 Second composite component, 310 Third composite component, 312 Air gap, 313 Composite filler, 314 Fiber optic cable, 316 Connector, 318 Connector, 320 First end, 322 Second end, 324 Second fiber optic cable, 700 Aircraft manufacturing and maintenance methods / Aircraft, 702 Specifications and design, 704 Material procurement, 706 Component and subassembly manufacturing, 708 System integration, 710 Certification and delivery, 712 In-service, 714 Maintenance and overhaul, 800 Aircraft, 802 Airframe, 804 Systems, 806 Interior, 808 Propulsion systems, 810 Electrical systems, 812 Hydraulic systems, 814 Environmental systems

Claims

1. a void (208, 312) formed by at least two composite components (204, 206, 306, 308); a composite filler (210, 313) within the void (208, 312); a fiber optic cable (216, 314) extending through the gap (208, 312) extending from at least one of a first end (212, 320) of the gap (208, 312) and a second end (214, 322) of the gap (208, 312); Equipped with The fiber optic cable (216, 314) contacts the composite filler (210, 313), and the composite splice inspection system (218, 304) does so.

2. The composite joint inspection system (218, 304) of claim 1, wherein the fiber optic cable (216, 314) is embedded within the composite filler (210, 313).

3. 2. The composite joint inspection system (218, 304) of claim 1, wherein the fiber optic cable (216, 314) is in contact with an outer surface (237) of one of the at least two composite components (204, 206, 306, 308) and the composite filler (210, 313).

4. a second fiber optic cable (217, 324) extending through the gap (208, 312) from at least one of the first end (212, 320) of the gap (208, 312) and the second end (214, 322) of the gap (208, 312); The composite splice inspection system (218, 304) of claim 1, wherein the second fiber optic cable (217, 324) is positioned within the composite filler (210, 313).

5. The composite joint inspection system (218, 304) of claim 1, further comprising an optical emitter (228) connected to the fiber optic cable (216, 314).

6. The composite joint inspection system (218, 304) of claim 5, further comprising a data acquisition system (226) connected to the fiber optic cable (216, 314).

7. a composite joint (207, 303) having an integrated strain detector; The composite joint is a first composite component (204, 306); a second composite component (206, 308); a composite filler (210, 313) positioned in a void (208, 312) between the first composite component (204, 306) and the second composite component (206, 308); a fiber optic cable (216, 314) extending through the gap (208, 312) extending from at least one of a first end (212, 320) of the gap (208, 312) and a second end (214, 322) of the gap (208, 312); Equipped with The optical fiber cable (216, 314) is in contact with the composite filler (210, 313).

8. 8. The aircraft (100, 244, 700) of claim 7, wherein the fiber optic cable (216, 314) is embedded within the composite filler (210, 313).

9. 8. The aircraft (100, 244, 700) of claim 7, wherein the fiber optic cable (216, 314) is in contact with a surface (237) of the first composite component (204, 306) and the composite filler (210, 313).

10. a second fiber optic cable (217, 324) extending through the gap (208, 312) extending from at least one of the first end (212, 320) of the gap (208, 312) and the second end (214, 322) of the gap (208, 312); 8. The aircraft (100, 244, 700) of claim 7, wherein the second fiber optic cable (217, 324) is positioned within the composite filler (210, 313).

11. 8. The aircraft (100, 244, 700) of claim 7, further comprising an optical emitter (228) connected to the first end (212, 320) of the fiber optic cable (216, 314).

12. The aircraft (100, 244, 700) of claim 11, further comprising a data acquisition system (226) connected to the second end (214, 322) of the fiber optic cable (216, 314).

13. A method (400) for inspecting a composite joint (207, 303), comprising: sending (402) a light wave (230) through a fiber optic cable (216, 314) extending through a gap (208, 312) of the composite joint (207, 303), the fiber optic cable (216, 314) extending from at least one of a first end (212, 320) of the gap (208, 312) and a second end (214, 322) of the gap (208, 312), the fiber optic cable (216, 314) contacting a composite filler (210, 313) in the gap (208, 312); measuring (404) the reflectance index (224) of light received from said fiber optic cable (216, 314); comparing (406) the measured reflectance index (224) with a baseline (222) reading; The method (400) includes:

14. 14. The method (400) of claim 13, further comprising the step of determining (418) whether distortion has affected the composite joint (207, 303) based on the step of comparing the measured reflectance index (224) to the reference line (222) reading.

15. Attaching (414) a light emitter (228) to the fiber optic cable (216, 314); Attaching (416) a data acquisition system (226) to the fiber optic cable (216, 314); 14. The method (400) of claim 13, further comprising:

16. placing (408) the composite filler (210, 313) in the void (208, 312) between at least two composite components (204, 206, 306, 308); placing (410) the fiber optic cable (216, 314) in the gap (208, 312) such that the fiber optic cable (216, 314) contacts the composite filler (210, 313); 14. The method (400) of claim 13, further comprising:

17. 17. The method (400) of claim 16, further comprising the step (412) of injecting a resin into the composite filler (210, 313) and the at least two composite components (204, 206, 306, 308) to form the composite joint (207, 303) having an integrated strain detector.

18. A method (500) of forming a composite joint (207, 303), comprising: placing (502) a composite filler (210, 313) in a void (208, 312) between at least two composite components (204, 206, 306, 308); placing (504) the fiber optic cable (216, 314) in the gap (208, 312) such that the fiber optic cable (216, 314) contacts the composite filler (210, 313); injecting (506) a resin into the composite filler (210, 313) and at least two of the composite components (204, 206, 306, 308) to form the composite joint (207, 303) having an integrated strain detector; The method (500) includes:

19. further comprising the step of extruding (508) the fiber optic cable (216, 314) into the composite filler (210, 313); 20. The method (500) of claim 18, wherein placing the fiber optic cable (216, 314) in the void (208, 312) is performed by placing the composite filler (210, 313) in the void (208, 312).

20. placing (510) the fiber optic cable (216, 314) in the gap (208, 312) includes contacting the fiber optic cable (216, 314) with a first composite component (204, 306) of the at least two composite components (204, 206, 306, 308); 20. The method (500) of claim 18, wherein placing the composite filler (210, 313) in the void (208, 312) comprises contacting the composite filler (210, 313) with the fiber optic cable (216, 314).

21. Attaching (512) a light emitter (228) to the fiber optic cable (216, 314); Attaching (514) a data acquisition system (226) to the fiber optic cable (216, 314); 20. The method (500) of claim 18, further comprising:

22. at least two composite components (204, 206, 306, 308) joined together at a composite joint (207, 303); a composite filler (210, 313) within the composite joint (207, 303); a fiber optic cable (216) embedded between layers of the composite component (204) of at least two of said composite components (204, 206, 306, 308); Equipped with A composite joint inspection system (218, 304), wherein the fiber optic cable (216) extends along the composite joint and extends from at least one of a first end (250) of the composite component (204) and a second end (252) of the composite component (204).

23. 23. The composite joint inspection system (218, 304) of claim 22, further comprising a second fiber optic cable (217) embedded within the composite filler (210, 313).

24. 23. The composite joint inspection system (218, 304) of claim 22, wherein the fiber optic cable (216) is embedded within ten composite plies of the composite joint (207, 303).

25. A method (600) for inspecting a composite structure (202, 302), comprising: sending (602) light waves through a fiber optic cable (216) extending through a composite structure (202, 302), the fiber optic cable (216) extending from at least one of a first end of the composite structure (202, 302) and a second end of the composite structure (202, 302), the fiber optic cable (216) contacting the composite structure (202, 302); measuring (604) the reflectance index (224) of light received from said fiber optic cable (216); comparing (606) the measured reflectance index (224) with a baseline (222) reading; The method (600).

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