Apparatus and method for acoustic modeling of defects in composite materials with calibration panels formed from additive manufacturing

Abstract

This application is entitled "Apparatus and Method for Acoustic Modeling of Defects in Composite Materials with Calibration Panels Formed by Additive Manufacturing." Disclosed herein is a calibration panel that models acoustic properties of defects in a vehicle component made of a composite material. The calibration panel includes a body formed by a first digital material through additive manufacturing, the acoustic properties of which are selected to approximate acoustic properties of the composite material, and an insert embedded within the body, the insert formed at least of a second digital material, the acoustic properties of which are selected to approximate acoustic properties of a defect within the composite material. Also disclosed herein is a method for manufacturing a vehicle component that complies with non-destructive evaluation (NDE). The method includes receiving a proposed design of a component, manufacturing a calibration panel, and testing the calibration panel to determine whether the insert is detectable using acoustic emission testing. The method further includes rejecting the proposed design of the component in response to a non-detectable state of the insert.

Description

Technical Field

[0001] This invention relates generally to nondestructive testing of composite materials, and more particularly to the manufacture of calibration plates for acoustic nondestructive testing of composite materials. Background Technology

[0002] Transportation vehicles, including aircraft, are increasingly using components made from composite materials. For example, large parts of an aircraft (such as wings, tail fins, stabilizers, and fuselage) can be constructed from fiber-reinforced polymer laminates. Many other smaller components of aircraft are also being formed from composite laminates. To ensure safety, these components must undergo rigorous testing procedures. Non-destructive testing techniques, such as ultrasonic quantitative analysis, provide information about the manufacturing quality, material strength, and service life of components. However, such non-destructive testing techniques may require reference or calibration structures, which are often handcrafted and time-consuming to manufacture, to ensure that the manufactured parts are properly tested. Summary of the Invention

[0003] The subject matter of this application provides an example calibration panel that overcomes the shortcomings of the prior art described above. The subject matter of this application was developed in response to the current state of the art, particularly in response to the shortcomings of current component design, testing, and manufacturing methods.

[0004] This document discloses a calibration panel comprising a body formed by additive manufacturing of a first digital material whose acoustic properties are selected to approximate those of a composite material. The calibration panel further comprises an insert embedded within the body, the insert being formed of at least a second digital material whose acoustic properties are selected to approximate those of defects within a composite material. Example 1 of the invention is described above.

[0005] In some examples, the calibration panel includes a front surface and an opposing rear surface. In some examples, the insert is embedded within the body at a distance from the front surface, said distance being chosen to approximate the depth of the defect within the composite material. The preceding subject matter describes Example 2 of the invention, which also includes the subject matter according to Example 1 described above.

[0006] The defects are selected from the group consisting of voids, pores, non-uniform material distribution, delamination, contaminants, inclusions, and damage. The preceding subject matter describes Example 3 of the invention, which also includes the subject matter according to any one of Examples 1 or 2 above.

[0007] In some embodiments, the second digital material is based on an acoustic impedance value Z' determined according to the following formula. d To choose:

[0008]

[0009] Z d It is the impedance of the actual defect, Z b It is the impedance of the composite material, Z' d It is the impedance of the defect, and Z' b It is the impedance of the subject. The preceding subject matter describes Example 4 of the invention, wherein Example 4 also includes the subject matter according to any one of Examples 1-3 above.

[0010] In some examples, the insert is formed of a second digital material and at least a third digital material. The preceding subject matter describes Example 5 of the invention, which also includes the subject matter of any of Examples 1-4 above.

[0011] The insert is formed to have a thickness based on the difference between the sound velocity passing through the defect and the sound velocity passing through the composite material. The preceding subject matter describes Example 6 of the invention, which further includes the subject matter of Example 5 described above.

[0012] In some examples, the volume fraction f of the second digital material is based on the desired speed of sound C. d The elastic modulus E1 of the second material, the elastic modulus E2 of the third material, the density ρ1 of the second material, the density ρ2 of the third material, the Poisson's ratio ν1 of the second material, and the Poisson's ratio ν2 of the third material, wherein the volume fraction f is determined according to the following formula:

[0013]

[0014] The preceding topic describes Example 7 of the present invention, wherein Example 7 also includes the subject matter of Example 6 described above.

[0015] Desired speed of sound C d The sound speed through the defect, wherein the sound speed through the second digital material is less than the desired sound speed C. d The preceding text describes Example 8 of the invention, which also includes the subject matter according to Example 7 described above.

[0016] Additionally, this document discloses a method for manufacturing a calibration panel. In some examples, the method includes forming a body from a first digital material via additive manufacturing, the acoustic properties of which are selected to approximate the acoustic properties of a composite material, and mixing a second digital material and a third digital material to form an insert, wherein the acoustic property value of the second digital material is less than the acoustic property value of a defect in the composite material, and wherein the acoustic property value of the third digital material is greater than the acoustic property value of a defect. The method also includes embedding the insert within the body. Example 9 of the invention has been described in the preceding headings of this paragraph.

[0017] The method also includes forming a front surface and an opposing rear surface. The preceding subject matter describes Example 10 of the invention, which also includes the subject matter according to Example 9 described above.

[0018] The method also includes embedding the insert within the body at a distance from the front surface, said distance being chosen to approximate the depth of the defect within the composite material. The preceding subject matter describes Example 11 of the invention, wherein Example 11 also includes the subject matter according to Example 10 described above.

[0019] The method also includes embedding the insert within the body at a distance from the front surface, the distance being selected based on the difference between the sound velocity of the composite material and the sound velocity of the first digital material. The preceding section describes Example 12 of the subject matter disclosure, wherein Example 12 also includes the subject matter according to Example 10 described above.

[0020] The method also includes selecting defects from the group consisting of voids, pores, non-uniform material distribution, delamination, contaminants, inclusions, and damage. The preceding subject matter describes Example 13 of the invention, which also includes the subject matter according to any one of Examples 9-12 above.

[0021] The method also includes a method based on the desired speed of sound C. d The volume fraction f of the second digital material is determined by the elastic modulus E1 of the second digital material, the elastic modulus E2 of the third digital material, the density ρ1 of the second digital material, the density ρ2 of the third digital material, the Poisson's ratio ν1 of the second digital material, and the Poisson's ratio ν2 of the third digital material. In some examples, the method further includes determining the volume fraction f according to the following formula:

[0022]

[0023] The preceding subject matter describes Example 14 of the invention, wherein Example 14 also includes the subject matter according to any one of Examples 9-13 above.

[0024] Desired speed of sound C d This is equivalent to the speed of sound passing through a defect, and the method also includes selecting one digital material from a variety of digital materials as a second digital material, wherein the second digital material has a speed of sound less than the desired speed C. d The speed of sound through the second digital material. The preceding subject matter describes Example 15 of the invention, wherein Example 15 also includes the subject matter according to Example 14 described above.

[0025] The method also includes selecting one digital material from a variety of digital materials as a third digital material, wherein the third digital material has a sound speed greater than the desired speed C. dThe speed of sound through a third digital material. The preceding subject matter describes Example 16 of the invention, wherein Example 16 also includes the subject matter according to Example 15 described above.

[0026] This document also discloses a method for manufacturing a component conforming to nondestructive evaluation (NDE). In some instances, the method includes receiving design data representing a proposed design of the component and manufacturing a reference standard model of the component. The reference standard model includes a body formed by additive manufacturing of a first digital material whose acoustic properties are selected to approximate the acoustic properties of a composite material specified within the design data, and an insert embedded within the body, the insert being formed of at least a second digital material whose acoustic properties are selected to approximate the acoustic properties of defects within the composite material. The method also includes testing the reference standard model to determine whether the insert is testable using acoustic emission testing, and rejecting the proposed design of the component in response to the undetectable state of the insert. Example 17 of the invention is described above.

[0027] The method also includes forming an insert from a composition of a second digital material and at least a third digital material. The preceding subject matter describes Example 18 of the invention, wherein Example 18 also includes the subject matter according to Example 17 described above.

[0028] The method also includes a method based on the desired speed of sound C. d The volume fraction f of the second digital material is determined by the elastic modulus E1 of the second digital material, the elastic modulus E2 of the third digital material, the density ρ1 of the second digital material, the density ρ2 of the third digital material, the Poisson's ratio ν1 of the second digital material, and the Poisson's ratio ν2 of the third digital material. In some examples, the method further includes determining the volume fraction f according to the following formula:

[0029]

[0030] The preceding subject matter describes Example 19 of the present invention, wherein Example 19 also includes the subject matter according to Example 18 described above.

[0031] Desired speed of sound C d This is equivalent to the speed of sound passing through a defect, and the method also includes selecting one digital material from a variety of digital materials as a second digital material, wherein the second digital material has a speed of sound less than the desired speed C. d The speed of sound through the second digital material. The preceding subject matter describes Example 20 of the invention, wherein Example 20 also includes the subject matter according to Example 19 described above.

[0032] The features, structures, advantages, and / or characteristics of the subject matter of the invention described herein can be combined in any suitable manner in one or more examples (including embodiments and / or implementations). Numerous specific details are provided in the following description to give a thorough understanding of the examples of the subject matter of the invention. Those skilled in the art will recognize that the subject matter of the invention can be practiced without the presence of one or more specific features, details, components, materials, and / or methods of a particular example, embodiment, or implementation. In other instances, additional features and advantages may be recognized in certain examples, embodiments, and / or implementations that are not presented in all examples, embodiments, or implementations. Furthermore, in some cases, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring various aspects of the subject matter of the invention. The features and advantages of the subject matter of the invention will become more apparent from the following description and the appended claims, or may be learned by practice of the subject matter described below. Attached Figure Description

[0033] To facilitate a clearer understanding of the advantages of the subject matter, a more specific description of the subject matter, briefly outlined above, will be presented with reference to specific examples shown in the accompanying drawings. It should be understood that these drawings depict only typical examples of the subject matter and should not be considered as limiting its scope. The subject matter will be described and explained with additional specificity and detail using the accompanying drawings, wherein:

[0034] Figure 1 This is a schematic block diagram illustrating an example of a system including an additive manufacturing or three-dimensional (3D) printer according to the present invention;

[0035] Figure 2 This illustrates an example according to the invention. Figure 1 A schematic block diagram of the system controller;

[0036] Figure 3 This is a schematic block diagram showing the top of a calibration panel according to an example of the present invention;

[0037] Figure 4 This illustrates an example according to the invention. Figure 3 A schematic block diagram of one side of the calibration panel; and

[0038] Figure 5 This is a schematic flowchart illustrating an iterative component design method according to an example of the present invention. Detailed Implementation

[0039] Throughout this specification, references to “an example,” “example,” or similar language mean that a particular feature, structure, or characteristic described in connection with that example is included in at least one example of the invention. The phrases “in an example,” “in a sample,” and similar language appearing in this specification may (but not necessarily) all refer to the same example. Similarly, the term “implementation” is used to refer to an implementation having a particular feature, structure, or characteristic described in connection with one or more examples of the invention; however, unless explicitly indicated otherwise, an implementation may be associated with one or more examples.

[0040] This invention describes an apparatus and method for additively manufacturing a reference panel (e.g., a calibration panel) that simulates the acoustic properties of a vehicle component or part. In some examples, inserts with acoustic properties selected to simulate defects are embedded in the calibration panel. Many vehicle components require non-destructive evaluation (NDE) capabilities. Determining whether a new proposed design has NDE capabilities requires creating a calibration panel with intentionally defective features and then performing NDE tests to determine if the defects are detected. The systems and methods disclosed herein provide the ability to achieve quantifiable and / or repeatable acoustic properties, which is valuable in the manufacture of NDE reference standards. Additive manufacturing of the calibration panel (e.g., 3D printing) significantly accelerates the iteration cycle of the proposed part's design. As described in more detail below, the materials used to create the calibration panel are selected to simulate the acoustic properties of the proposed part design. In particular, in some examples, the acoustic properties of defects in a composite structure are simulated (or modeled) by mixing two or more materials.

[0041] Figure 1 This is a schematic block diagram illustrating an example of an additive manufacturing or three-dimensional (3D) printer 102 according to the present invention. The 3D printer 102 is configured to construct three-dimensional objects by selectively depositing chemical components (e.g., polymer components) onto a platform 104. The chemical components are made of one or more different materials, each fed by a corresponding one of one or more supply tanks 106 of the 3D printer 102. The combination of one or more materials forming the chemical component is presented to one or more printheads 108 of the 3D printer 102. A controller 107 receives a design plan and instructs the 3D printer 102 to fabricate a calibration panel 110 by depositing the chemical components layer by layer onto the platform 104 using the printheads 108. Each chemical component is deposited from the printheads 108 as dispensing droplets. These layers are hardened or cured using a suitable mechanism (not shown) (e.g., including a heater or an ultraviolet (UV) radiator). In another example, the hardening or curing of each deposited droplet of chemical component is activated by contact with an adjacent droplet.

[0042] In some examples, each voxel of the calibration panel 110 is printed with a different chemical composition. A "voxel" refers to a value representing a volume element in three-dimensional space in the design plan. Similar to a pixel in two-dimensional space, a voxel is an individually addressable volume element with definable physical properties. Multiple voxels define the configuration of the calibration panel 110. In some examples, the controller 107 instructs the 3D printer 102 to form a different chemical composition for each voxel of one or more "digital materials." The volume fraction f of the digital material in the chemical composition of each voxel is selected based on the desired acoustic properties, as will be referenced below. Figure 2 This will be discussed in more detail. As used herein, the phrase "digital material" refers to a modeling material at the voxel scale used in 3D printing to form the calibration panel 110. In some examples, the digital material is also a material composed of one or more base materials with variable (but controlled) mixing ratios. These base materials are made of chemically compatible and stable resins that can be mixed and matched together. In various examples, photopolymers with rubber-like properties are mixed with photopolymers with ABS-like properties.

[0043] For clarity, many components of the 3D printer 102, such as heaters, radiation sources, leveling devices, and air supply devices, are omitted. One or more print heads 108 receive one or more digital materials from supply tanks 106. Each supply tank 106 is a reservoir or hopper for feeding material to the print head 108. The 3D printer also includes a curing system suitable for the type of material being deposited. In some examples, the curing system uses ultraviolet, visible, or infrared light to cure the material. Other examples of curing systems include microwave radiation sources, ultrasonic radiation sources, etc.

[0044] In some examples, the print head 108 is movable relative to the platform 104. Alternatively, both the print head 108 and the platform 104 are movable relative to the frame (not shown) housing the 3D printer 102. Typically, the platform 104 is configured to move upwards and downwards (Z-axis) toward and away from the print head 108, while the print head 108 is configured to move in the XY plane (Y-axis defined as the page-in / out direction, X-axis defined as the left / right direction). In some examples, a heater is provided within the housing of the 3D printer 102 to maintain an elevated temperature that ensures the components are in liquid form to allow the print head 108 to dispense them.

[0045] In some examples, the digital material used to form the calibration panel 110 is selected to simulate the acoustic properties of the proposed vehicle component. For example, if the proposed vehicle component is formed of a carbon fiber composite material, the calibration panel 110 is formed of a “base” digital material that simulates the acoustic properties of carbon fiber. According to some examples, inserts formed of a second digital material (see...) Figure 3 The calibration panel 110 is embedded within the calibration panel to simulate defects that may exist or are prone to exist in the proposed vehicle components. Testing the compatibility of the calibration panel 110 with NDE ultrasonic testing equipment allows component designers to determine whether the proposed component design will meet NDE capability requirements.

[0046] As will be described in more detail below, controller 107 controls the mixing of digital material from print head 108 and feed canister 106. In some examples, the controller translates a design plan into instructions that can be executed by 3D printer 102. For example, the design plan may be in Standard Mosaic Language (STL) format. Furthermore, controller 107 is configured to modify the STL format of the design plan to include voxel-level material composition information, as referenced below. Figure 2 As stated above.

[0047] Figure 2 This is a schematic block diagram illustrating a controller 107 according to an example of the present invention. The controller 107 is an example of a computing device that, in some examples, implements one or more components of an example of the present disclosure, and in which computer-usable program code or instructions implementing the process can be located for the illustrative example. In this illustrative example, the controller includes a communication structure 202 that provides communication between a processor unit 204, a mixture generator 205, a memory 206, a permanent storage device 208, a communication unit 210, and a display 212.

[0048] In some examples, processor unit 204 is used to execute instructions of software loaded into memory 206. In one example, processor unit 204 is a collection of one or more processors, or it may be a multiprocessor core, depending on the specific implementation. Furthermore, according to some examples, processor unit 204 is implemented using one or more heterogeneous processor systems, where the main processor and auxiliary processors reside on a single chip. As another illustrative example, processor unit 204 is a symmetric multiprocessor system containing multiple processors of the same type.

[0049] Mixture generator 205 is configured to determine the composition of different digital materials that will match or approximate the acoustic properties of the base composite material as well as the acoustic properties of different defects within the base composite material. In some examples, this acoustic property is the velocity of sound through the material. Other acoustic properties include, but are not limited to, reflection, frequency, noise, attenuation, and / or impedance. Mixing various materials together in different volume fractions results in different velocities of sound. Therefore, mixture generator 205 can advantageously create different compositions that simulate the acoustic properties of the base (or bulk) composite material as well as the acoustic properties that simulate the defects within the composite material. This allows for the rapid fabrication of calibration panels as alternatives to proposed part designs to determine whether the proposed part design will conform to NDE standards. The ability to achieve quantifiable and repeatable acoustic properties is of significant value in NDE reference standard fabrication. For example, defects such as air gaps, overlays, and foreign objects can be identified by adding inserts (see [link to NDE reference standard fabrication]). Figure 3 It is modeled by embedding it into the main body of the calibration panel 110.

[0050] In some examples, the mixture generator 205 maintains a database of acoustic properties (e.g., sound velocity through a particular material, reflectivity, etc.), particularly those digital materials in supply tank 106. The mixture generator 205 receives the desired location, quantity, and type of defects to be modeled in calibration panel 110 from the design plan and modifies the design plan using the compositional information used to simulate or model the defects. In some examples, the mixture generator 205 receives the design plan via communication unit 210. This design plan is stored in storage device 216. For example, the mixture generator 205 is configured to determine the volume fraction of a first digital material and a second digital material that will result in the desired acoustic properties. The desired acoustic properties (e.g., sound velocity) correspond to the desired defect type. In some examples, the design plan is received via communication unit 210 and / or stored in storage device 216.

[0051] In one example, the mixture generator 205 determines the components of the mixture selected to simulate the desired acoustic properties according to the following formula:

[0052]

[0053] The volume fraction f of the first digital material is based on the desired speed of sound C. d The elastic modulus E1 of the first digital material, the elastic modulus E2 of the second digital material, the density ρ1 of the first digital material, the density ρ2 of the second digital material, the Poisson's ratio ν1 of the first digital material, and the Poisson's ratio ν2 of the second digital material. Sound waves propagate due to the vibration or oscillating motion of particles in the material, and are therefore a function of the elastic modulus E.

[0054] When selecting the first and second digital materials, the mixture generator 205 selects a sound velocity less than the desired sound velocity C in some examples. d A digital material (i.e., the speed of sound of the desired defect) and a speed of sound greater than C d Another digital material. Then, the mixture generator 205 determines the appropriate volume fraction of the two digital materials to achieve C. d As described above, this determination is made according to a formula or alternatively according to a lookup table maintained by the mixture generator 205 (e.g., stored in the storage device 216).

[0055] In some examples, the mixture generator 205 also considers the frequency of the acoustic signal, since changing the frequency will result in a change in the wavelength of the sound when the speed of sound is constant. Therefore, the wavelength of the ultrasonic nondestructive testing instrument has a significant impact on the probability of detecting discontinuities. According to some examples, the mixture generator 205 also considers noise, which is the result of competing reflections within the microstructure grains. A good measure of defect detectability is the signal-to-noise ratio (SNR), which is a means of measuring the comparison between the signal from the defect and other background reflections (classified as "noise"). An example of a suitable SNR according to the embodiments of the present invention is 3:1.

[0056] In some embodiments, the mixture generator 205 takes reflectivity into account. In some examples, this reflectivity is used to identify defects within the body 110 when an ultrasonic signal is reflected and the remaining signal is transmitted through the body 110. Accordingly, in some examples, an insert embedded within the calibration panel simulates the acoustic properties of reflectivity. The reflectivity R is typically determined by the following formula:

[0057]

[0058] Z d It is the defective ultrasonic impedance, and Z b This is the ultrasonic impedance of the main body. The impedance of the defect or main body is related to the density of the defect or main body and the sound velocity of the defect or main body. The mixture generator 205 is configured to simulate the reflection of defects in the proposed component design using the insert in the main body by adjusting the acoustic impedance of the insert (see...). Figure 3 ). In Z d It is the impedance of the actual defect, Z b It is the impedance of the composite material used in the proposed component design, Z' d It is the impedance of the simulated defect, while Z' b In the case of the impedance of the body of the calibration panel, in some examples, the mixture generator 205 is based on the calculated Z' d The following formula is used to select digital materials:

[0059]

[0060] And the known impedance value of the material. In other words, in some examples, the mixture generator 205 selects a digital material with a known impedance that matches the impedance determined by the formula to simulate the impedance of the desired defect.

[0061] In some embodiments, the mixture generator 205 also considers attenuation, i.e., how sound intensity decreases with distance. Furthermore, in some examples, the mixture generator 205 considers impedance, which is defined as the product of material density and sound velocity. Impedance can be used to determine sound transmission and reflection at the boundary between two materials with different acoustic impedances to assess sound absorption in the medium.

[0062] Memory 206 and permanent storage device 208 are examples of storage device 216. A storage device is any piece of hardware capable of temporarily and / or permanently storing information (e.g., but not limited to data, program code in functional form, and / or other suitable information). In these examples, memory 206 is random access memory or any other suitable volatile or non-volatile storage device. Permanent storage device 208 takes various forms depending on the specific implementation. In one example, permanent storage device 208 includes one or more components or devices. In one example, permanent storage device 208 is a hard disk drive, flash memory, rewritable optical disk, rewritable magnetic tape, or some combination thereof. In some examples, the medium used in permanent storage device 208 is removable. For example, in various implementations, a removable hard disk drive is used for permanent storage device 208.

[0063] In some examples, communication unit 210 provides communication with other data processing systems or devices. In these examples, communication unit 210 is a network interface card. Communication unit 210 provides communication using one or both of a physical communication link and a wireless communication link. In some examples, communication unit 210 also provides a connection for user input via a keyboard, mouse, and / or some other suitable input device. Furthermore, in various examples, the input / output unit sends output to a printer or receives input from any other peripheral device. Display 212 provides a mechanism for displaying information to the user.

[0064] In some examples, instructions for the operating system, applications, and / or programs reside in storage device 216, which communicates with processor unit 204 via communication structure 202. In these illustrative examples, these instructions exist functionally in permanent memory 208. In some examples, these instructions are loaded into memory 206 for execution by processor unit 204. In some examples, processes of different kinds are executed by processor unit 204 using computer-implemented instructions residing in memory (e.g., memory 206).

[0065] These instructions are referred to as program code, computer-usable program code, or computer-readable program code that can be read and executed by the processor in processor unit 204. In different examples, the program code is embodied on different physical or computer-readable storage media, such as memory 206 or permanent storage device 208.

[0066] Program code 218 is located in a functional form on a selectively removable computer-readable medium 220 and can be loaded onto or transferred to controller 107 for execution by processor unit 204. In some examples, the program code also includes the references above. Figure 1 The repair plan under discussion. Program code 218 and computer-readable medium 220 form computer program product 222. In one example, computer-readable medium 220 is computer-readable storage medium 224 or computer-readable signal medium 226. In one example, computer-readable storage medium 224 includes an optical disc or disk that is inserted into or placed in a drive or other device that is part of permanent storage device 208 for transfer to a storage device (e.g., a hard disk drive) that is part of permanent storage device 208. In other examples, computer-readable storage medium 224 also takes the form of a permanent storage device, such as a hard disk drive, thumb drive, or flash memory connected to controller 107. In some instances, computer-readable storage medium 224 is not removable from controller 107.

[0067] Alternatively, computer-readable signal medium 226 may be used to transmit program code 218 to controller 107. As an example, computer-readable signal medium 226 is a propagated data signal containing program code 218. For example, in one example, computer-readable signal medium 226 is an electromagnetic signal, an optical signal, and / or any other suitable type of signal. These signals are transmitted via a communication link (e.g., a wireless communication link, fiber optic cable, coaxial cable, wire, and / or any other suitable type of communication link). In other words, in the illustrative example, the communication link and / or connection is physical or wireless. In some examples, the computer-readable medium may also take the form of a non-tangible medium, such as a communication link containing program code or a wireless transmission.

[0068] In some illustrative examples, program code 218 is downloaded from another device or data processing system via a network to permanent storage device 208 for use within controller 107 via computer-readable signal medium 226. In one instance, program code stored in a computer-readable storage medium in a server data processing system is downloaded from a server to controller 107 via a network. Depending on the various examples, the system providing program code 218 is a server computer, a client computer, or some other device capable of storing and transmitting program code 218.

[0069] The different components illustrated for controller 107 do not imply any physical or architectural limitations on how different examples can be implemented. Different illustrative examples can be implemented in a controller that includes components attached to and / or replacing those components illustrated for controller 107. Figure 2 Other components shown may differ from the illustrative example shown. Different examples can be implemented using any hardware device or system capable of executing program code. For example, the storage device in controller 107 is any hardware device capable of storing data. Memory 206, permanent storage device 208, and computer-readable medium 220 are examples of tangible storage devices.

[0070] In another example, a bus system is used to implement communication structure 202 and may include one or more buses, such as a system bus or input / output bus. Of course, in some examples, the bus system is implemented using any suitable type of architecture that provides data transfer between different components or devices attached to the bus system. In additional examples, the communication unit includes one or more devices for sending and receiving data, such as a modem or network adapter. Furthermore, memory, such as memory 206 or a cache, may be found, for example, in the interface and memory controller hub that may be present in communication structure 202.

[0071] Computer program code used to implement various aspects of the present invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​(e.g., Java, Smalltalk, C++, etc.) and conventional procedural programming languages ​​(e.g., the "C" programming language or similar programming languages). The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer can be connected to the user's computer via any type of network (including a local area network (LAN) or a wide area network (WAN)), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0072] These computer program instructions may also be stored in a computer-readable medium that instructs a computer, other programmable data processing apparatus, or other device to operate in a particular manner, causing the instructions stored in the computer-readable medium to produce an article of manufacture, including instructions that implement the functions / actions specified in flowcharts and / or block diagram blocks. The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device, thereby producing a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide a process for implementing the functions / actions specified in flowcharts and / or block diagram blocks.

[0073] Figure 3 This is a schematic block diagram showing the top of a calibration panel 110 according to an example of the invention. In some examples, the calibration panel 110 is formed as a rectangular block. The calibration panel 110 is formed of a block material selected to simulate the acoustic properties of a proposed component. In some examples, the proposed component is formed of a composite material (e.g., carbon fiber and resin). Therefore, the block material selected to simulate the acoustic properties has acoustic properties that simulate composite carbon fiber. Embedded within the calibration panel are inserts 302. Each insert 302 is selected to simulate different types of defects within the proposed component. For example, one of the inserts 302 is formed of a component that simulates an air gap. In an alternative example, the controller 107 is configured to control the 3D printer 102 to form an air gap within the calibration panel 110. In some examples, the inserts 302 are formed of a component that simulates other types of defects (including, but not limited to, foreign matter, overlapping trim panels, and / or other acoustic anomalies within the composite).

[0074] Each insert 302 is formed from different components of digital material. (See above for reference.) Figure 2 The composition is determined by the mixture generator 205. Although the inserts 302 are depicted as being uniformly distributed, it should be understood that the inserts 302 may be positioned randomly and / or stacked on top of each other.

[0075] Figure 4This is a schematic block diagram of one side of a calibration panel 110 according to an example of the invention. In the depicted embodiment, the calibration panel 110 has a thickness between a front surface 402 and a rear surface 404. In some examples, this thickness is chosen to approximate the thickness of the proposed component design. A controller 107 is configured to embed the insert 302 between the front surface 402 and the insert 302 at different distances (i.e., depths) 406. This is advantageous for allowing component designers to test for defects at different depths in the proposed component. For example, if the proposed component is formed of multiple layers of carbon fiber, the controller 107 is configured to adjust the embedding distance 406 of the insert 302 to simulate, for example, a defect between the third and fourth layers of a composite material. In an additional example, inserts 302 with different thicknesses 408 are formed and embedded. By changing the thickness of the insert 302, the insert 302 is adjusted to approximate the speed of sound in an actual defect. For example, if a digital material is not available to approximate a certain defect, a digital material with a similar but faster speed of sound can be selected and embedded at an increased thickness. The increased thickness causes sound to travel through the defect for a longer time, thus approximating a defect with a slower sound speed.

[0076] In some embodiments, the calibration panel 110 is substantially rectangular as shown. Alternatively, the calibration panel 110 is formed in a shape similar to the proposed component design. In some examples, the proposed component is a panel or other structural part used in the manufacture of a vehicle (especially an aircraft). In some examples, the proposed component is any part of a vehicle that benefits from NDE testing or is required to have NDE capability. If the calibration panel 110 fails the NDE test (i.e., the device fails to detect one of the inserts 302), this indicates that the proposed design is likely not NDE capable.

[0077] Figure 5 This is a schematic flowchart illustrating a method 500 for iterative part design according to an example of the present invention. In some examples, method 500 includes receiving design data representing a proposed part design at step 502 and selecting a first digital material that approximates the acoustic properties of a composite material specified in the design data. In some examples, the design data is a digital representation of a proposed 3D part having information defining each voxel of the 3D part. The method also includes selecting defects at step 504 and mapping these defects into the proposed part design. In some examples, mapping defects into the proposed part design includes determining the location and depth of inserts for modeling the selected defects.

[0078] In step 506, method 500 determines the volume fraction of acoustic modeling material (e.g., digital material) corresponding to the acoustic properties of the selected defect. In some examples, the acoustic properties include sound velocity, or in other words, the sound velocity through the defect. (See above reference...) Figure 2The process involves selecting a second digital material whose acoustic property value is less than that of the defect, and then selecting a third digital material whose acoustic property value is greater than that of the defect. In some examples, the volume fraction of these digital materials is determined by a formula.

[0079] In step 508, method 500 determines the location of the modeling defect within calibration panel 110. In step 510, method 500 includes manufacturing the calibration panel based on the determined volume fraction and location, and embedding insert 302 into calibration panel 110.

[0080] In step 512, method 500 determines whether the manufactured calibration panel 110 has NDE capability. In other words, method 500 determines whether the NDE testing instrument can detect the insert 302 simulating a defect in the proposed part design. In some examples, method 500 indicates that the calibration panel has one of a "detectable state" or a "non-detectable state". If the determination is negative, method 500 rejects the proposed part design in step 514, and method 500 returns to step 502.

[0081] In the above description, certain terms may be used, such as “above,” “below,” “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,” “above,” “below,” etc. Where applicable, these terms are used to provide a clear description when dealing with relationships. However, these terms do not imply absolute relationships, positions, and / or directions. For example, for an object, simply by flipping the object over, the “upper” surface can become the “lower” surface. However, it is still the same object. Furthermore, unless otherwise expressly stated, the terms “including,” “comprising,” “having,” and their variations mean “including but not limited to.” Unless otherwise expressly stated, the list of listed items does not imply that any or all items are mutually exclusive and / or mutually inclusive. Unless otherwise expressly stated, the terms “a,” “an,” and “the” also mean “one or more.” Additionally, the term “multiple” can be defined as “at least two.”

[0082] Furthermore, instances of one element being "coupled" to another element in this specification can include direct coupling and indirect coupling. Direct coupling can be defined as one element coupling to another element and making some kind of contact with the other element. Indirect coupling can be defined as coupling between two elements that are not in direct contact with each other, but with one or more additional elements between these coupled elements. Additionally, as used herein, fixing one element to another element can include direct fixing and indirect fixing. Furthermore, as used herein, "adjacent" does not necessarily mean contact. For example, one element may be adjacent to another element without contacting that element.

[0083] As used in this article, the phrase "at least one" when used with a list of items means that different combinations of one or more of the listed items may be used, and only one of the items in the list is required. The item can be a specific object, thing, or category. In other words, "at least one" means any combination or number of items that can be used from the list, but not all items in the list are required. For example, "at least one of items A, B, and C" can mean: item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, "at least one of items A, B, and C" can mean, but is not limited to: two items A, one item B, and ten items C; four items B and seven items C; or some other suitable combination.

[0084] Unless otherwise stated, the terms “first,” “second,” etc., are used merely as labels in this document and are not intended to impose any order, position, or hierarchy requirements on the items referred to by these terms. Furthermore, for example, mentioning a “second” item does not require or exclude the existence of, for example, “first” or lower numbered items and / or, for example, “third” or higher numbered items.

[0085] In this document, the terms “includes,” “including,” “have,” “contain,” and their variations are intended to be included as open transition words in a manner similar to the term “comprises,” without excluding any additional or other elements.

[0086] As used herein, a system, apparatus, structure, article, element, component, or hardware "configured" to perform a specified function is indeed capable of performing the specified function without any changes, and not merely has the potential to perform the specified function after further modification. In other words, a system, apparatus, structure, article, element, component, or hardware "configured" to perform a specified function is specifically selected, created, implemented, utilized, programmed, and / or designed to perform the specified function. As used herein, "configured" indicates existing characteristics of a system, apparatus, structure, article, element, component, or hardware that enable the system, apparatus, structure, article, element, component, or hardware to perform the specified function without further modification. For the purposes of this invention, a system, apparatus, structure, article, element, component, or hardware described as "configured" to perform a particular function may additionally or alternatively be described as "suitable" and / or "operably" to perform that function.

[0087] The schematic flowcharts included herein are generally conceived as logical flowcharts. Therefore, the depicted sequence and labeled steps indicate an example of the method. Other steps and methods that are functionally, logically, or effectively equivalent to one or more steps or portions thereof in the illustrated method can be envisioned. Furthermore, the formatting and symbols used are provided to interpret the logical steps of the method and are understood not to limit the scope of the method. While various arrow and line types may be used in flowcharts, they are understood not to limit the scope of the corresponding methods. In practice, some arrows or other connectors may only be used to represent the logical flow of a method. For example, an arrow may indicate a wait or monitoring period of unspecified duration between the enumerated steps of an illustrated method. Moreover, the order in which a particular method occurs may or may not strictly follow the order of the corresponding steps shown.

[0088] Furthermore, this disclosure includes embodiments as described in the following terms:

[0089] Clause 1. A calibration panel comprising:

[0090] The main body (110) is formed by additive manufacturing of a first digital material, the acoustic properties of which are selected to approximate those of a composite material; and

[0091] An insert (302) embedded in the body (110) is formed of at least a second digital material whose acoustic properties are selected to approximate the acoustic properties of defects within a composite material.

[0092] Clause 2. The calibration panel according to Clause 1, wherein the body (110) further includes:

[0093] Front surface (402);

[0094] The relative rear surface (404); and

[0095] The insert (302) is embedded in the body (110) at a certain distance (406) from the front surface (402), the distance being chosen to approximate the depth of the defect in the composite material.

[0096] Clause 3. The calibration panel as described in Clause 1 or 2, wherein the defect is selected from the group consisting of voids, pores, non-uniform material distribution, delamination, contaminants, inclusions and damage.

[0097] Clause 4. The calibration panel according to any one of Clauses 1-3, wherein the second digital material is based on the acoustic impedance value Z' determined according to the following formula. d To choose:

[0098]

[0099] Z d It is the impedance of the actual defect, Z b It is the impedance of the composite material, Z' d It is the impedance of the defect, and Z' b It is the impedance of the main body.

[0100] Clause 5. The calibration panel according to any one of Clauses 1-4, wherein the insert (302) is formed of a composition of a second digital material and at least a third digital material.

[0101] Clause 6. The calibration panel according to Clause 5, wherein the insert (302) is formed to have a thickness (408) based on the difference between the sound velocity passing through the defect and the sound velocity passing through the composition.

[0102] Clause 7. The calibration panel as described in Clause 6, wherein the volume fraction f of the second digital material is based on the desired velocity of sound C. d The elastic modulus E1 of the second material, the elastic modulus E2 of the third material, the density ρ1 of the second material, the density ρ2 of the third material, the Poisson's ratio ν1 of the second material, and the Poisson's ratio ν2 of the third material, wherein the volume fraction f is determined according to the following formula:

[0103]

[0104] Clause 8. The calibration panel as described in Clause 7, wherein the desired speed of sound C d The sound speed through the defect, wherein the sound speed through the second digital material is less than the desired sound speed C. d .

[0105] Clause 9. A method of manufacturing a calibration panel, the method comprising:

[0106] The body (110) is formed by additive manufacturing of a first digital material, the acoustic properties of which are selected to be similar to those of a composite material;

[0107] A second digital material and a third digital material are mixed to form an insert (302), wherein the second digital material has an acoustic property value smaller than that of a defect within the composite material, and wherein the acoustic property value of the third digital material is larger than that of the defect; and

[0108] The insert (302) is embedded into the body (110).

[0109] Clause 10. The method described in Clause 9 further includes forming a front surface (402) and an opposing rear surface (404).

[0110] Clause 11. The method according to Clause 10, wherein the embedded insert (302) further includes embedding the insert (302) into the body (110) at a distance (406) from the front surface (404), the distance being selected to approximate the depth of the defect within the composite material.

[0111] Clause 12. The method according to Clause 10, wherein the embedded insert (302) further includes embedding the insert (302) within the body (110) at a distance (406) from the front surface (404), the distance being selected based on the difference between the sound velocity of the composite material and the sound velocity of the first digital material.

[0112] Clause 13. The method according to any one of Clauses 9-12 further includes selecting defects from the group consisting of voids, pores, non-uniform material distribution, delamination, contaminants, inclusions and damage.

[0113] Clause 14. The method according to any one of Clauses 9-13, wherein the volume fraction f of the second digital material is based on the desired velocity of sound C. d The method further includes determining the volume fraction f according to the following formula: the elastic modulus E1 of the second material, the elastic modulus E2 of the third material, the density ρ1 of the second material, the density ρ2 of the third material, the Poisson's ratio ν1 of the second material, and the Poisson's ratio ν2 of the third material.

[0114]

[0115] Clause 15. The method described in Clause 14, wherein the desired speed of sound C d Equivalent to the speed of sound passing through a defect, and the method further includes selecting one digital material from a variety of digital materials as a second digital material, wherein the second digital material has a speed of sound less than the desired speed of sound C. d The speed of sound through the second digital material.

[0116] Clause 16. The method according to Clause 15 further includes selecting one digital material from a plurality of digital materials as a third digital material, wherein the third digital material has a sound velocity greater than the desired speed C. d The speed of sound through the third digital material.

[0117] Clause 17. A method for manufacturing a component conforming to nondestructive evaluation (NDE), the method comprising:

[0118] Receive design data representing the proposed design of the component;

[0119] A reference standard model for manufacturing this component, wherein the reference standard model includes:

[0120] The body (110) is formed by additive manufacturing of a first digital material whose acoustic properties are selected to approximate those of a composite material specified in the design data.

[0121] as well as

[0122] An insert (302) embedded in the body (110) is formed of at least a second digital material whose acoustic properties are selected to approximate the acoustic properties of defects in a composite material;

[0123] The reference standard model was tested to determine whether the insert (302) was testable using acoustic emission testing; and

[0124] In response to the undetectable state of the insert (302), the proposed design of the component is rejected.

[0125] Clause 18. The method according to Clause 17 further includes forming an insert (302) from a composition of a second digital material and at least a third digital material.

[0126] Clause 19. The method according to Clause 18, wherein the volume fraction f of the second digital material is based on the desired velocity of sound C. d The method further includes determining the volume fraction f according to the following formula: the elastic modulus E1 of the second material, the elastic modulus E2 of the third material, the density ρ1 of the second material, the density ρ2 of the third material, the Poisson's ratio ν1 of the second material, and the Poisson's ratio ν2 of the third material.

[0127]

[0128] Clause 20. The method described in Clause 19, wherein the desired speed of sound C d Equivalent to the speed of sound passing through a defect, and the method further includes selecting one digital material from a variety of digital materials as a second digital material, wherein the second digital material has a speed of sound less than the desired speed of sound C. d The speed of sound through the second digital material.

[0129] The disclosed subject matter may be embodied in other specific forms without departing from its spirit and essential characteristics. The described examples are to be regarded in all respects as illustrative rather than restrictive. All modifications within the equivalent meaning and scope of the claims should be included within their scope.

Claims

1. A calibration panel for simulating the acoustic properties of defective composite materials, comprising: The main body (110) is formed by additive manufacturing of a first digital material, the acoustic properties of which are selected to approximate those of a composite material; as well as An insert (302) is embedded within the body (110), the insert (302) being formed of at least a second digital material whose acoustic properties are selected to approximate the acoustic properties of a defect within the composite material, the first and second digital materials being modeling materials at the voxel level, wherein a voxel is an individually addressable volume element in three-dimensional space, and the acoustic properties of the composite material and the defect are the velocity of sound waves passing through the composite material and the defect or the reflection, frequency, noise, attenuation, and impedance of sound waves.

2. The calibration panel according to claim 1, wherein the main body (110) further comprises: Front surface (402); The opposite rear surface (404); as well as The insert (302) is embedded in the body (110) at a distance (406) from the front surface (402), the distance being chosen to approximate the depth of the defect within the composite material.

3. The calibration panel according to claim 1 or 2, wherein the defect is selected from the group consisting of voids, pores, non-uniform material distribution, delamination, contaminants, inclusions and damage.

4. The calibration panel according to claim 1 or 2, wherein the second digital material is based on an acoustic impedance value Z' determined according to the following formula. d To choose: Z d It is the impedance of the actual defect, Z b Z' is the impedance of the composite material. d It is the impedance of the defect, and Z' b It is the impedance of the main body.

5. The calibration panel according to claim 1 or 2, wherein the insert (302) is formed of a composition of the second digital material and at least a third digital material, wherein the third digital material is based on an acoustic impedance value Z' determined according to the following formula. d To choose: Z d It is the impedance of the actual defect, Z b Z' is the impedance of the composite material. d It is the impedance of the defect, and Z' b It is the impedance of the main body.

6. The calibration panel according to claim 5, wherein the insert (302) is formed to have a thickness (408) based on the difference between the sound velocity passing through the defect and the sound velocity passing through the composition.

7. The calibration panel of claim 6, wherein the volume fraction f of the second digital material is based on the desired velocity of sound C. d The elastic modulus E1 of the second digital material, the elastic modulus E2 of the third digital material, the density ρ1 of the second digital material, the density ρ2 of the third digital material, the Poisson's ratio ν1 of the second digital material, and the Poisson's ratio ν2 of the third digital material, wherein the volume fraction f is determined according to the following formula:

8. The calibration panel of claim 7, wherein the desired speed of sound C d The sound speed through the defect, wherein the sound speed through the second digital material is less than the desired sound speed C. d .

9. A method of manufacturing a calibration panel, the method comprising: The body (110) is formed from a first digital material by additive manufacturing, wherein the acoustic properties of the first digital material are selected to approximate the acoustic properties of a composite material; A second digital material and a third digital material are mixed to form an insert (302), wherein the acoustic property value of the second digital material is less than the acoustic property value of the defect in the composite material, and wherein the acoustic property value of the third digital material is greater than the acoustic property value of the defect, wherein the first and second digital materials are modeling materials at the voxel level, wherein a voxel is an individually addressable volume element in three-dimensional space, and the acoustic properties of the composite material and the defect are the velocity of sound waves passing through the composite material and the defect or the reflection, frequency, noise, attenuation, and impedance of sound waves; as well as The insert (302) is embedded within the body (110).

10. The method of claim 9, further comprising forming a front surface (402) and an opposing rear surface (404).

11. The method of claim 10, wherein embedding the insert (302) further comprises embedding the insert (302) into the body (110) at a distance (406) from the front surface (404), the distance being selected to approximate the depth of the defect in the composite material.

12. The method of claim 10, wherein embedding the insert (302) further comprises embedding the insert (302) within the body (110) at a distance (406) from the front surface (404), the distance being selected based on the difference between the sound velocity of the composite material and the sound velocity of the first digital material.

13. The method according to any one of claims 9-12, further comprising selecting the defect from the group consisting of voids, pores, non-uniform material distribution, delamination, contaminants, inclusions and damage.

14. The method according to any one of claims 9-13, wherein the volume fraction f of the second digital material is based on the desired speed of sound C. d The method further includes determining the volume fraction f according to the following formula: the elastic modulus E1 of the second digital material, the elastic modulus E2 of the third digital material, the density ρ1 of the second digital material, the density ρ2 of the third digital material, the Poisson's ratio ν1 of the second digital material, and the Poisson's ratio ν2 of the third digital material.

15. The method of claim 14, wherein the desired speed of sound C d Equivalent to the speed of sound passing through the defect, and the method further includes selecting one digital material from a plurality of digital materials as the second digital material, wherein the second digital material has a speed of sound less than the desired speed of sound C. d The speed of sound through the second digital material.

16. The method of claim 15, further comprising selecting a digital material from a plurality of digital materials as a third digital material, wherein the third digital material has a sound velocity C greater than the desired sound velocity C. d The speed of sound through the third digital material.

17. A method for manufacturing a component that conforms to nondestructive evaluation (NDE), the method comprising: Receive design data representing the proposed design of the component; A reference standard model for manufacturing the component, wherein the reference standard model includes: Body (110), the body being formed by additive manufacturing of a first digital material, the acoustic properties of which are selected to approximate the acoustic properties of a composite material specified within the design data; and An insert (302) is embedded within the body (110), the insert (302) being formed of at least a second digital material whose acoustic properties are selected to approximate the acoustic properties of a defect within the composite material, the first and second digital materials being modeling materials at the voxel level, wherein a voxel is an individually addressable volume element in three-dimensional space, and the acoustic properties of the composite material and the defect are the velocity of sound waves passing through the composite material and the defect or the reflection, frequency, noise, attenuation, and impedance of sound waves; The reference standard model was tested to determine whether the insert (302) was testable using acoustic emission testing; and In response to the undetectable state of the insert (302), the proposed design of the component is rejected.

18. The method of claim 17, further comprising forming the insert (302) from a composition of the second digital material and at least a third digital material, wherein the third digital material has an acoustic property value greater than the acoustic property value of the defect.

19. The method of claim 17, further comprising manufacturing a calibration panel of the reference standard model including the component, wherein the calibration panel is further manufactured by forming a front surface and an opposing rear surface; and embedding the insert further comprises embedding the insert within the body at a distance from the front surface, the distance being selected to approximate the depth of the defect within the composite material.

20. The method of claim 18, wherein the volume fraction f of the second digital material is based on the desired speed of sound C. d The method further includes determining the volume fraction f according to the following formula: the elastic modulus E1 of the second digital material, the elastic modulus E2 of the third digital material, the density ρ1 of the second digital material, the density ρ2 of the third digital material, the Poisson's ratio ν1 of the second digital material, and the Poisson's ratio ν2 of the third digital material.

21. The method of claim 20, wherein the desired speed of sound C d Equivalent to the speed of sound passing through the defect, and the method further includes selecting one digital material from a plurality of digital materials as the second digital material, wherein the second digital material has a speed of sound less than the desired speed of sound C. d The speed of sound through the second digital material.

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