Manufacturing method of defect simulation test block, defect simulation test block and detection method of defect simulation test block

Abstract

The invention belongs to the technical field of aircraft manufacturing, and discloses a defect simulation test block manufacturing method, a defect simulation test block and a detection method thereof.The defect simulation test block manufacturing method comprises the following steps that S1, core material fragmentation defect parameters are determined; s2, according to the core material fragmentation defect parameters, a core material fragmentation interface layer is manufactured and formed, and a core material fragmentation interface layer placement groove is formed in the target foam core material test block through machining; s3, the core material fragmentation interface layer is placed in the core material fragmentation interface layer placing groove; s4, test block adhesive films and prepregs are laid on the upper surface and the lower surface of the target foam core material test block, bagging and curing are carried out, and the simulation test block is formed. The core material fragmentation interface layer is firstly manufactured, then the simulation test block is manufactured, it is guaranteed that the core material fragmentation interface layer in the simulation test block is consistent with the determined core material fragmentation defect parameter, it is effectively avoided that in the prior art, the defect manufactured on a cured composite material structure is deviated from a target defect, and a stable and reliable sample can be provided for follow-up detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft manufacturing, in particular to a method for manufacturing a defect simulation test block, a defect simulation test block and a detection method thereof. BACKGROUND

[0002] The foam sandwich structure includes a foam core material in the innermost layer, a film coated on the outer periphery of the foam core material, and a skin coated on the outer periphery of the film. It is widely used in aircraft rudder surfaces, hatches and blades and other structures due to its excellent moisture resistance.

[0003] During the manufacturing and use of the foam sandwich structure, core material fragmentation defects may occur due to external mechanical loads. The existence of the core material fragmentation defects reduces the carrying capacity of the overall structure and brings serious safety hazards to the product.

[0004] Currently, when simulating the core material fragmentation defects, a rigid blade or a steel sheet is usually inserted directly into the foam sandwich structure by artificial to manufacture defects for simulation, and then the foam sandwich structure is detected and analyzed. However, in the process of manufacturing artificial defects, the differences between the artificial defects and the defects to be simulated are caused due to the influence of subjective factors, resulting in inaccurate simulation results.

[0005] Therefore, there is an urgent need for a method for manufacturing a defect simulation test block, a defect simulation test block and a detection method thereof to solve the above problems. SUMMARY

[0006] The purpose of the present application is to provide a method for manufacturing a defect simulation test block to solve the technical problem that the detection results are inaccurate due to the differences between the artificial defects and the actual defects in the prior art, and to achieve the technical effect of improving the accuracy of the detection results.

[0007] As conceived above, the technical solution adopted by the present application is:

[0008] The method for manufacturing a defect simulation test block is used to manufacture a simulation test block of a core material fragmentation defect of a foam sandwich structure, and includes the following steps:

[0009] S1, determining a core material fragmentation defect parameter;

[0010] S2, according to the core material fragmentation defect parameter, forming a core material fragmentation interface layer and a core material fragmentation interface layer placement groove on a target foam core material test block;

[0011] S3, placing the core material fragmentation interface layer in the core material fragmentation interface layer placement groove;

[0012] S4, laying a test block film and a prepreg on the entire upper and lower surfaces of the target foam core material test block, and performing bagging and curing to form a defect simulation test block.

[0013] Further, the step S2 comprises:

[0014] S21, bonding the prepreg film on the prepreg foam core material, and curing the two to form a prepreg;

[0015] S22, after the surface of the prepreg foam core material of the prepreg away from the prepreg film is peeled to the thickness of the prepreg meeting the design requirements, cutting to the cross-sectional size meeting the design requirements to form the core material fragmentation interface layer;

[0016] Or after the prepreg is cut to the cross-sectional size of the prepreg meeting the design requirements, the surface of the prepreg foam core material of the prepreg away from the prepreg film is peeled to the thickness meeting the design requirements to form the core material fragmentation interface layer.

[0017] Further, the core material fragmentation defect parameter comprises a diameter φd and a design depth h1;

[0018] In the step S1, the skin thickness h2 laid on the target foam core test block also needs to be determined;

[0019] In the step S22, the prepreg is processed to a thickness of h1-h2 and a diameter of φd to form the core material fragmentation interface layer.

[0020] Further, in the step S1, the test block film thickness h3 laid on the target foam core test block also needs to be determined, and the diameter of the core material fragmentation interface layer placement groove is φd and the depth is h1-h2-h3.

[0021] Further, in the step S2, after the core material fragmentation interface layer is completed, the core material fragmentation interface layer is subjected to quality inspection, and if qualified, the step S3 is executed; if not qualified, the step S2 is re-executed.

[0022] Further, when the core material fragmentation interface layer is subjected to quality inspection, the inspection method is optical detection, ray detection or ultrasonic detection.

[0023] Further, the steps S1-S4 are repeatedly executed to form a plurality of defect simulation test blocks of different sizes.

[0024] Another object of the present application is to provide a defect simulation test block which can ensure that the manufactured defects are consistent with the defects to be simulated.

[0025] As conceived above, the technical solution adopted by the present application is:

[0026] The defect simulation test block is manufactured by using the manufacturing method of the defect simulation test block.

[0027] The application further aims to provide a detection method of the core material fragmentation defect simulation test block for the foam sandwich structure, which can obtain the detection signal of the simulation test block.

[0028] According to the above idea, the technical scheme adopted by the application is as follows:

[0029] The detection method of the defect simulation test block is used to detect the defect simulation test block to obtain the detection signal of the simulation test block.

[0030] Further, the detection signal is an ultrasonic detection signal, and the detection signal includes a scattering echo at the rear end of the glue film echo of the defect simulation test block.

[0031] The application has the following beneficial effects:

[0032] The manufacturing method of the defect simulation test block provided by the application can ensure that the core material fragmentation interface layer in the simulation test block is consistent with the determined core material fragmentation defect parameter, effectively avoids the deviation between the manually manufactured defect and the target defect in the existing technology, and can provide a stable and reliable sample for subsequent detection.

[0033] The defect simulation test block provided by the application can ensure that the core material fragmentation interface layer in the simulation test block is consistent with the target defect without deviation, is stable and reliable, and can be used as a comparison sample for subsequent detection of the foam sandwich structure.

[0034] The detection method of the defect simulation test block provided by the application can obtain the detection signal of the simulation test block with the determined target defect. When the actual product is detected subsequently, the detection signal of the actual product is compared with the detection signal of the simulation test block, and the defect information of the actual product can be determined. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of the contents of the embodiments of the present application and the drawings.

[0036] Figure 1 is a flowchart of the method for manufacturing the defect simulation test block provided by the embodiment of the present application;

[0037] Figure 2 is a flowchart of the method for manufacturing the core material fragmentation interface layer provided by the embodiment of the present application;

[0038] Figure 3 is a structural diagram of the preform provided by the embodiment of the present application;

[0039] Figure 4 is a schematic diagram of the preform peeling in the method for manufacturing the defect simulation test block provided by the embodiment of the present application;

[0040] Figure 5 is a structural diagram of the core material fragmentation interface layer provided by the embodiment of the present application;

[0041] Figure 6 is a structural diagram of the core material fragmentation interface layer placement groove provided by the embodiment of the present application;

[0042] Figure 7 is an exploded view of the defect simulation test block provided by the embodiment of the present application;

[0043] Figure 8 is an ultrasonic detection signal of the test block without the core material fragmentation defect;

[0044] Figure 9 is an ultrasonic detection signal of the defect simulation test block provided by the embodiment of the present application.

[0045] In the drawings:

[0046] 1, target foam core test block; 11, core material fragmentation interface layer placement groove; 21, preform adhesive film; 22, preform foam core; 3, core material fragmentation interface layer; 4, defect simulation test block. EMBODIMENTS

[0047] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the present application will be further described below in conjunction with the accompanying drawings and specific embodiments. It can be understood that the specific embodiments described here are only used to explain the present application, but not limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, not all.

[0048] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0049] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or it can be detachable connection; it can be mechanical connection, or it can be electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0050] As Figures 1-7 shown, the present embodiment provides a method for manufacturing a defect simulation test block, the defect simulation test block 4 for manufacturing core material fragmentation defects of a foam sandwich structure, comprising the following steps:

[0051] S1, determining the core material fragmentation defect parameters;

[0052] S2, according to the core material fragmentation defect parameters, manufacturing the core material fragmentation interface layer 3, and processing the core material fragmentation interface layer placement groove 11 on the target foam core test block 1;

[0053] S3, placing the core material fragmentation interface layer 3 in the core material fragmentation interface layer placement groove 11;

[0054] S4, laying the test block adhesive film and the prepreg on the upper and lower surfaces of the target foam core test block 1, and performing bagging and curing to form the defect simulation test block 4.

[0055] By first making a core material fragmentation interface layer 3, and then opening a core material fragmentation interface layer placement groove 11 that matches the core material fragmentation interface layer 3 in the target foam core material specimen 1, the core material fragmentation interface layer 3 is placed in the core material fragmentation interface layer placement groove 11, and then applying specimen film and prepreg to the upper and lower surfaces of the target foam core material specimen 1 for bagging and curing to make a defect simulation specimen 4, it is ensured that the core material fragmentation interface layer 3 in the defect simulation specimen 4 is consistent with the determined core material fragmentation defect parameters, effectively avoiding the deviation between the artificially manufactured defects and the target defects when artificially manufacturing defects on the composite material structure after curing in the prior art, and can provide a stable and reliable sample for subsequent detection.

[0056] At the same time, after the defect simulation test block 4 is produced, the defect simulation test block 4 can be tested and the detection signal of the defect simulation test block 4 can be obtained. When the subsequent operator tests the actual product, he can compare the detection result of the defect simulation test block 4 with the detection signal of the actual product to correctly judge the defect information of the actual product.

[0057] Furthermore, if Figures 2 to 5 As shown, in this embodiment, step S2 includes:

[0058] S21, bonding the preform adhesive film 21 to the preform foam core material 22, and bagging and curing the two to form a preform. Figure 3 First, bagging and curing the preform foam core material 22 and the preform adhesive film 21 can realistically simulate the bonding state of the foam core material and the adhesive film in the foam sandwich structure, and accurately simulate the core material fracture interface layer generated when the foam sandwich structure is subjected to mechanical load in real situations.

[0059] S22, peeling operation is performed on the surface of the preform foam core material 22 of the preform away from the preform adhesive film 21 until the thickness of the preform meets the design requirements. Figure 4 Then cut it to the cross-sectional size to meet the design requirements, forming, forming Figure 5 The core material fracture interface layer 3 is shown;

[0060] Alternatively, after cutting the preform until the interface size of the preform meets the design requirements, the preform foam core material 22 of the preform is peeled off from the surface of the preform film 21 away from the preform until the thickness meets the design requirements, forming a Figure 5 The core material is shown as a broken interface layer 3.

[0061] By curing the prepreg foam core material 22 and the prepreg film 21 after bagging, and then processing them to form the core material fragmentation interface layer 3, the various uncertainties that occur when the core material fragmentation interface layer 3 is made in the cured foam sandwich structure in the prior art can be avoided, the precise control of the state characteristic information of the core material fragmentation interface layer 3 is realized, and the parameters of the core material fragmentation interface layer 3 are ensured to be consistent with the core material fragmentation defect parameters.

[0062] Generally, the foam sandwich structure will produce debonding defects or delamination defects inside after being subjected to mechanical load; in the embodiment, the fragmentation interface layer 3 is embedded in the target foam core material test block 1, which can accurately simulate the defect.

[0063] Further, the core material fragmentation defect parameters include the diameter φd and the design depth h1. In step S1, the skin thickness h2 to be laid on the target foam core material test block 1 also needs to be determined. In step S22, the prepreg is stripped to a thickness of h1-h2 and cut to a diameter of φd to form the core material fragmentation interface layer 3.

[0064] Specifically, in the embodiment, the core material fragmentation defect parameters diameter φd and design depth h1 and the skin thickness h2 to be laid on the target foam core material test block are first determined. (The prepreg is cured to form the skin) Then, a prepreg foam core material 22 with a thickness greater than h1-h2 is selected, and a prepreg film 21 is bonded to the prepreg foam core material 22, and the two are cured in a bag to form a prepreg. Then, the prepreg foam core material 22 of the prepreg is stripped on the surface away from the prepreg film 21 until the thickness of the prepreg is h1-h2, and then the prepreg with a thickness of h1-h2 is cut to form a core material fragmentation interface layer 3 with a cross-sectional size of φd. In this way, after the core material fragmentation interface layer 3 is placed in the core material fragmentation interface layer placement groove 11, when the test block film is laid, the uncured test block film can flow on the upper surface of the target foam core material test block 1 and the upper surface of the core material fragmentation interface layer 3. When the prepreg is laid and cured in a bag, most of the test block film is pressed between the prepreg and the upper surface of the target foam core material test block 1, and after the defect simulation test block 4 is made, the test block film thickness between the core material fragmentation interface layer 3 and the skin can be ignored, and the upper surface of the core material fragmentation interface layer 3 can be flush with the upper surface of the film in the defect simulation test block 4.

[0065] Specifically, the stripping operation can be performed manually with tools such as knives, steel sheets, or sandpaper, or by mechanical processing such as a vertical stripping machine. Whether it is manual tool holding or mechanical processing, it only needs to start from the surface of the prepreg foam core material 22 of the prepreg away from the prepreg film 21 and strip until the thickness of the prepreg is h1-h2.

[0066] Further, as Figure 6As shown, in the present embodiment, in step S1, the thickness h3 of the test block adhesive film to be laid on the target foam core test block 1 also needs to be determined. Furthermore, the diameter of the core material fragmentation interface layer placement groove 11 is determined as φd, and the depth is h1-h2-h3. In this way, the diameter of the core material fragmentation interface layer placement groove 11 is consistent with the diameter of the core material fragmentation interface layer 3, and the depth of the core material fragmentation interface layer placement groove 11 is consistent with the thickness of the foam core of the core material fragmentation interface layer 3. Furthermore, when the core material fragmentation interface layer 3 is placed in the core material fragmentation interface layer placement groove 11, the foam core of the core material fragmentation interface layer 3 can be placed in the core material fragmentation interface layer placement groove 11, thereby simulating the actual situation of the foam core having a defect.

[0067] Further, in step S2, after the core material fragmentation interface layer 3 is completed, the quality of the core material fragmentation interface layer 3 is checked. If it is qualified, step S3 is performed; if it is not qualified, step S2 is re-executed. In this way, the quality of the core material fragmentation interface layer 3 can be ensured, and the quality and detection results of the defect simulation test block 4 will not be affected by the quality problem of the core material fragmentation interface layer 3, so that the defect simulation test block 4 obtained meets the expectations.

[0068] Further, when the quality of the core material fragmentation interface layer 3 is checked, the checking method is optical detection, ray detection, or ultrasonic detection.

[0069] Optionally, in the present embodiment, after the core material fragmentation interface layer 3 is completed, the optical detection method is to observe and detect the appearance of the core material fragmentation interface layer 3 using an optical microscope to check whether there is obvious debonding phenomenon, such as cracks, waves, etc.

[0070] Optionally, in other embodiments, the quality of the core material fragmentation interface layer 3 can also be checked by ray detection or ultrasonic detection. Specifically, the ray detection method is X-ray detection. Specifically, the ultrasonic detection method is phased array ultrasonic detection.

[0071] Only when the core material fragmentation interface layer 3 meets the requirements, the target foam core test block 1 is placed in the core material fragmentation interface layer placement groove 11, and the test block adhesive film and the prepreg are laid to form the defect simulation test block 4 after bagging and curing. Figure 7

[0072] ​Further, the steps S1-S4 are repeated to make a plurality of defect simulation test blocks 4 of different sizes. By making a plurality of defect simulation test blocks 4 of different sizes, detection signals of the defect simulation test blocks 4 of different sizes can be obtained. With the detection signals of the defect simulation test blocks 4 of different sizes as the judgment standard, the condition of the core material inside the foam sandwich structure needs to be judged in the future. Only the detection signals of the foam sandwich structure are obtained by detecting the foam sandwich structure, and the detection signals of the foam sandwich structure are compared with the detection signals of the defect simulation test blocks 4 of different sizes. The parameter information of the core material fragmentation defect of the foam sandwich structure can be quickly and accurately judged. For example, if the detection signals of the foam sandwich structure are consistent with the detection signals of a certain defect simulation test block 4, it is considered that the core material fragmentation defect parameters of the foam sandwich structure are consistent with the core material fragmentation defect parameters of the defect simulation test block 4.

[0073] The application also provides a defect simulation test block of a core material fragmentation defect of a foam sandwich structure, which is made by the method for making a simulation test block of a core material fragmentation defect of a foam sandwich structure.

[0074] The application also provides a detection method for a simulation test block of a core material fragmentation defect of a foam sandwich structure, which comprises detecting the defect simulation test block 4 to obtain the detection signals of the defect simulation test block 4.

[0075] Further, the detection signal is an ultrasonic detection signal, and the detection signal includes a scattered echo at the back end of the adhesive film echo of the defect simulation test block 4.

[0076] Specifically, in the embodiment, the ultrasonic detection signals of the defect simulation test block 4 are obtained by an ultrasonic detection device. In use, the detection probe of the ultrasonic detection device is attached to the outer surface of the defect simulation test block 4 for detection. By using the propagation and reflection characteristics of ultrasonic waves, when the core material fragmentation defect occurs, the discontinuity of the material will prevent the ultrasonic waves from further propagating and scattering to the deeper part of the foam core of the defect simulation test block 4, and the scattered echo will quickly disappear.

[0077] Specifically, in the embodiment, a gate for monitoring the scattered echo is added at the back end of the adhesive film echo of the defect simulation test block 4 in the ultrasonic detection device. The gate is a processing method based on a time window. By sampling and analyzing the signal within a certain time window, the false judgment and missed detection caused by noise and other factors can be reduced. When the operator requires the ultrasonic detection device to compare and calculate a certain echo, the operator needs to "tell" the device which echo to track. The gate is used to lock the echo to be detected. The ultrasonic detection device processes and calculates the echo within the gate, and displays all parameters of the echo in real time. Specifically, as shown in FIG. 6, the gate is used to lock the echo to be detected. The ultrasonic detection device processes and calculates the echo within the gate, and displays all parameters of the echo in real time. Figure 8As shown, when the foam sandwich structure without the core material fragmentation defect is subjected to ultrasonic detection, the scattering and attenuation of the material itself to the ultrasonic energy is continuously increasing, the foam core material as a porous material continuously causes the scattering and dissipation of the ultrasonic energy, and the surface wave, the film wave and the scattering echo with gradually smaller energy amplitude can be obtained.

[0078] As shown, Figure 9 As shown, when the foam sandwich structure with the core material fragmentation defect (i.e. the defect simulation test block 4 in the embodiment) is subjected to ultrasonic detection, the discontinuity of the material will prevent the ultrasonic from propagating and scattering to the deeper part of the foam core material, and the scattering echo will disappear quickly.

[0079] Of course, in other embodiments, a gate for monitoring the scattering echo can also be added at the back end of the film echo of the defect simulation test block 4 in the signal processing system for processing the collected ultrasonic signal.

[0080] The above embodiments only illustrate the basic principles and characteristics of the present application, and the present application is not limited by the above embodiments. Various changes and modifications can be made to the present application without departing from the spirit and scope of the present application, and these changes and modifications all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for making a defect simulation test block, characterized in that: A defect simulation test block (4) for producing a core material fragmentation defect of a foam sandwich structure comprises the following steps: S1. Determine core material fragmentation defect parameters; S2, forming a core material fracture interface layer (3) according to the core material fracture defect parameters, and forming a core material fracture interface layer placement groove (11) on the target foam core material test block (1); S3, placing the core material fracture interface layer (3) in the core material fracture interface layer placement groove (11); S4, laying test block adhesive film and prepreg on the upper and lower surfaces of the target foam core material test block (1), and bagging and curing to form a defect simulation test block (4).

2. The method for making a defect simulation test block according to claim 1, characterized in that: The step S2 comprises: S21, bonding the preform adhesive film (21) to the preform foam core material (22), and bagging and curing the two to form a preform; S22, performing a peeling operation on the surface of the preform foam core material (22) of the preform away from the preform adhesive film (21) until the thickness of the preform meets the design requirements, and then cutting it to a cross-sectional size that meets the design requirements, thereby forming the core material fracture interface layer (3); Alternatively, after the preform is cut to a cross-sectional size that meets the design requirements, a peeling operation is performed on the surface of the preform foam core material (22) of the preform that is away from the preform adhesive film (21) until the thickness meets the design requirements, thereby forming the core material fracture interface layer (3).

3. The method for making a defect simulation test block according to claim 2, characterized in that: The core material fragmentation defect parameters include diameter φd and design depth h1; In the step S1, it is also necessary to determine the thickness h2 of the skin laid on the target foam core material test block (1); In the step S22, the preform is peeled off to a thickness of h1-h2 and cut into pieces with a diameter of φd to form the core material fracture interface layer (3).

4. The method for making a bubble defect simulation test block according to claim 3, characterized in that: In step S1, it is also necessary to determine the thickness h3 of the test block adhesive film laid on the target foam core material test block (1), and the diameter of the core material fracture interface layer placement groove (11) is φd and the depth is h1-h2-h3.

5. The method for making a defect simulation test block according to claim 1, characterized in that: In the step S2, after the core material fracture interface layer (3) is manufactured, the core material fracture interface layer (3) is subjected to a quality inspection. If it is qualified, the step S3 is executed; if it is unqualified, the step S2 is executed again.

6. The method for manufacturing a defect simulation test block according to claim 5, characterized in that: When the quality inspection of the core material fracture interface layer (3) is carried out, the inspection method is optical inspection, radiographic inspection or ultrasonic inspection.

7. The method for manufacturing a defect simulation test block according to any one of claims 1 to 6, characterized in that: Repeat steps S1 to S4 to produce a plurality of defect simulation test blocks (4) of different sizes.

8. Defect simulation test block, characterized in that: The defect simulation test block is manufactured by the method for manufacturing the defect simulation test block according to any one of claims 1 to 7.

9. A method for detecting defective simulation test blocks, characterized in that: The defect simulation test block (4) is detected to obtain a detection signal of the defect simulation test block (4), wherein the defect simulation test block (4) is manufactured using the manufacturing method of the defect simulation test block according to any one of claims 1 to 7.

10. The method for detecting defective simulation test blocks according to claim 9, characterized in that: The detection signal is an ultrasonic detection signal, and the detection signal includes a scattered echo at the rear end of the film echo of the defect simulation test block (4).

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