Methods for fabricating defect simulation test blocks, defect simulation test blocks and their testing methods
By creating a core material fracture interface layer and placement groove in the foam sandwich structure, combined with the curing treatment of adhesive film and prepreg, the problem of inaccurate artificial defects is solved, ensuring the stability and accuracy of test results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI AIRCRAFT MFG
- Filing Date
- 2025-01-14
- Publication Date
- 2026-07-17
AI Technical Summary
In existing technologies, artificially created defects differ from actual defects, leading to inaccurate test results.
By creating a core material fracture interface layer and opening corresponding placement grooves on the target foam core material test block, placing the core material fracture interface layer in the grooves, and then covering the upper and lower surfaces with test block adhesive film and prepreg for bagging and curing, a defect simulation test block is formed, ensuring that the core material fracture interface layer is consistent with the target defect parameters.
This method achieves zero deviation between the core material fracture interface layer and the target defect within the defect simulation test block, providing a stable and reliable test sample and ensuring the accuracy of the test results.
Smart Images
Figure CN120800929B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aircraft manufacturing technology, and in particular to a method for manufacturing defect simulation test blocks, defect simulation test blocks and their detection methods. Background Technology
[0002] Foam sandwich structures consist of an innermost foam core material, an outer periphery of which is covered by an adhesive film, and an outer periphery of which is covered by a skin. Due to its excellent moisture resistance, it is widely used in aircraft control surfaces, cabin doors, and propeller blades.
[0003] During the manufacturing and use of foam sandwich structures, core material fracture defects may occur due to external mechanical loads. The presence of core material fracture defects will reduce the load-bearing capacity of the overall structure and pose serious safety hazards to the product.
[0004] Currently, the simulation of core material fracture defects typically involves manually inserting rigid blades or steel sheets directly into the foam sandwich structure to create the defect, followed by inspection and analysis of the foam sandwich structure. However, during the artificial defect creation process, subjective human factors can easily lead to discrepancies between the artificially created defect and the intended defect, resulting in inaccurate simulation results.
[0005] Therefore, there is an urgent need for a method for manufacturing defect simulation test blocks, a defect simulation test block and its detection method, in order to solve the above problems. Summary of the Invention
[0006] The purpose of this invention is to provide a method for manufacturing a defect simulation test block, so as to solve the technical problem in the prior art that the difference between artificially manufactured defects and actual defects leads to inaccurate test results, and to achieve the technical effect of improving the accuracy of test results.
[0007] Based on the above concept, the technical solution adopted by this invention is as follows:
[0008] A method for fabricating a defect simulation test block, used to fabricate a simulation test block for core material fracture defects in foam sandwich structures, includes the following steps:
[0009] S1. Determine the parameters of core material fracture defects;
[0010] S2. Based on the core material fracture defect parameters, a core material fracture interface layer is formed, and a core material fracture interface layer placement groove is formed on the target foam core material test block.
[0011] S3. Place the core material fracture interface layer in the core material fracture interface layer placement groove;
[0012] S4. The test block adhesive film and prepreg are laid on the entire upper and lower surfaces of the target foam core material test block, and then bagged and cured to form a defect simulation test block.
[0013] Further, step S2 includes:
[0014] S21. Adhere the preformed adhesive film to the preformed foam core material, and then bag and cure the two to form a preform.
[0015] S22. After peeling the surface of the preformed foam core material away from the preformed adhesive film until the thickness of the preform meets the design requirements, it is then cut to meet the design requirements in terms of cross-sectional dimensions, forming the core material fracture interface layer.
[0016] Alternatively, after cutting the preform to the cross-sectional dimensions that meet the design requirements, peeling is performed from the surface of the preform foam core material away from the preform adhesive film until the thickness meets the design requirements, forming the core material fracture interface layer.
[0017] Furthermore, the core material fracture defect parameters include diameter φd and design depth h1;
[0018] In step S1, it is also necessary to determine the thickness h2 of the skin laid on the target foam core material test block;
[0019] In step S22, the preform is processed to a thickness of h1-h2 and a diameter of φd to form the core material fracture interface layer.
[0020] Furthermore, in step S1, it is also necessary to determine the thickness h3 of the adhesive film on the target foam core material test block, the diameter of the core material fracture interface layer placement groove is φd, and the depth is h1-h2-h3.
[0021] Furthermore, in step S2, after the core material fracture interface layer is manufactured, a quality inspection is performed on the core material fracture interface layer. If it is qualified, step S3 is executed; if it is unqualified, step S2 is executed again.
[0022] Furthermore, when performing quality inspection on the fractured interface layer of the core material, the inspection method is optical inspection, X-ray inspection, or ultrasonic inspection.
[0023] Further, repeat steps S1-S4 to create multiple defect simulation test blocks of different sizes.
[0024] Another objective of this invention is to provide a defect simulation test block that can ensure that the manufactured defect is consistent with the defect to be simulated.
[0025] Based on the above concept, the technical solution adopted by this invention is as follows:
[0026] The defect simulation test block is made using the aforementioned method for manufacturing defect simulation test blocks.
[0027] Another objective of this invention is to provide a method for detecting core material fracture defects in foam sandwich structures using simulated test blocks, which can acquire detection signals from the simulated test blocks.
[0028] Based on the above concept, the technical solution adopted by this invention is as follows:
[0029] The method for detecting defect simulation test blocks involves detecting the defect simulation test blocks to obtain detection signals, wherein the defect simulation test blocks are manufactured using the aforementioned defect simulation test block manufacturing method.
[0030] Furthermore, the detection signal is an ultrasonic detection signal, which includes the scattered echo at the rear end of the adhesive film echo of the defect simulation test block.
[0031] The beneficial effects of this invention are:
[0032] The method for fabricating a defect simulation test block provided by this invention involves first fabricating a core material fracture interface layer, then creating a core material fracture interface layer placement groove on a target foam core material test block to accommodate the core material fracture interface layer, placing the core material fracture interface layer in the groove so that its upper surface is flush with the upper surface of the target foam core material test block, and then applying a test block adhesive film and prepreg to both the upper and lower surfaces of the target foam core material test block for bagging and curing to create a simulation test block. This method ensures that the core material fracture interface layer within the simulation test block is consistent with the determined core material fracture defect parameters, effectively avoiding the deviation between artificially created defects and target defects when artificially manufactured defects are present on the cured composite material structure in existing technologies. This provides a stable and reliable sample for subsequent testing.
[0033] The defect simulation test block provided by this invention can ensure that the core material fracture interface layer in the defect simulation test block is consistent with the target defect, and is stable and reliable. It can be used as a comparison sample for subsequent testing of foam sandwich structures.
[0034] The defect simulation test block detection method provided by this invention can acquire the detection signal of a simulation test block with a defined target defect. When subsequently testing an actual product, the detection signal of the actual product is compared with the detection signal of the simulation test block to determine the defect information of the actual product. Attached Figure Description
[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.
[0036] Figure 1 This is a flowchart illustrating the method for fabricating a defect simulation test block according to a specific embodiment of the present invention;
[0037] Figure 2 This is a schematic diagram of the process for forming a core material fracture interface layer according to a specific embodiment of the present invention;
[0038] Figure 3 This is a schematic diagram of the structure of the preform provided in a specific embodiment of the present invention;
[0039] Figure 4 This is a schematic diagram of the preform peeling process in the method for manufacturing a defect simulation test block provided in a specific embodiment of the present invention.
[0040] Figure 5 This is a schematic diagram of the core material fracture interface layer provided in a specific embodiment of the present invention;
[0041] Figure 6 This is a schematic diagram of the structure of the core material fracture interface layer placement groove opened on the target foam core material test block according to a specific embodiment of the present invention;
[0042] Figure 7 This is an exploded view of the defect simulation test block provided in a specific embodiment of the present invention;
[0043] Figure 8 The ultrasonic test signal is from a test block that does not have core material fracture defects;
[0044] Figure 9 It is the ultrasonic detection signal of the defect simulation test block provided in the specific embodiment of the present invention.
[0045] In the picture:
[0046] 1. Target foam core material test block; 11. Core material fracture interface layer placement groove; 21. Precast adhesive film; 22. Precast foam core material; 3. Core material fracture interface layer; 4. Defect simulation test block. Detailed Implementation
[0047] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. Furthermore, it should be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, not all of them.
[0048] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions.
[0049] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.
[0050] like Figures 1-7 As shown, this embodiment provides a method for fabricating a defect simulation test block. The defect simulation test block 4, used to fabricate core material fracture defects in foam sandwich structures, includes the following steps:
[0051] S1. Determine the parameters of core material fracture defects;
[0052] S2. Based on the core material fracture defect parameters, a core material fracture interface layer 3 is formed, and a core material fracture interface layer placement groove 11 is formed on the target foam core material test block 1.
[0053] S3. Place the core material fracture interface layer 3 in the core material fracture interface layer placement groove 11;
[0054] S4. The test block adhesive film and prepreg are laid on both the upper and lower surfaces of the target foam core material test block 1, and then bagged and cured to form the defect simulation test block 4.
[0055] By first preparing a core material fracture interface layer 3, and then opening a core material fracture interface layer placement groove 11 in the target foam core material specimen 1 to accommodate the core material fracture interface layer 3, placing the core material fracture interface layer 3 in the core material fracture interface layer placement groove 11, and then applying a specimen film and prepreg to both the upper and lower surfaces of the target foam core material specimen 1 for bagging and curing, a defect simulation specimen 4 is prepared. This ensures that the core material fracture interface layer 3 in the defect simulation specimen 4 is consistent with the determined core material fracture defect parameters, effectively avoiding the deviation between the artificially created defects and the target defects when artificially creating defects on the cured composite material structure in the prior art, and providing a stable and reliable sample for subsequent testing.
[0056] Simultaneously, after the defect simulation test block 4 is manufactured, it can be tested and the test signal of the defect simulation test block 4 can be obtained. When the operator tests the actual product, he / she can compare the test signal of the actual product with the test result of the defect simulation test block 4 and correctly judge the defect information of the actual product.
[0057] Furthermore, such as Figures 2 to 5 As shown, in this embodiment, step S2 includes:
[0058] S21. Adhere the preformed adhesive film 21 to the preformed foam core material 22, and then bag and cure the two to form a preform. At this time, if Figure 3 As shown. First, the prefabricated foam core material 22 and the prefabricated adhesive film 21 are bagged and cured to realistically simulate the bonding state between the foam core material and the adhesive film in the foam sandwich structure, so as to accurately simulate the core material fracture interface layer caused by mechanical load on the foam sandwich structure in real situation.
[0059] S22. A peeling operation is performed on the surface of the precast foam core material 22 that is away from the precast adhesive film 21 until the thickness of the precast body meets the design requirements. At this point, if... Figure 4 As shown. Then cut to the required cross-sectional dimensions to form, as shown. Figure 5 The core material fracture interface layer 3 is shown;
[0060] Alternatively, after cutting the precast body to the interface dimensions that meet the design requirements, a peeling operation is performed on the surface of the precast body foam core material 22 that is away from the precast body adhesive film 21 until the thickness meets the design requirements, forming a shape like... Figure 5 The core material fracture interface layer 3 is shown.
[0061] By bagging and curing the preformed foam core material 22 and the preformed adhesive film 21, and then processing them to form the core material fracture interface layer 3, the various uncertainties that occur when making the core material fracture interface layer 3 in the cured foam sandwich structure in the existing methods can be avoided. This achieves precise control of the state characteristic information of the core material fracture interface layer 3 and ensures that the parameters of the core material fracture interface layer 3 are consistent with the core material fracture defect parameters.
[0062] Generally, foam sandwich structures will develop debonding or delamination defects when subjected to mechanical loads. In this embodiment, the fractured interface layer 3 is embedded in the target foam core material test block 1, which can accurately simulate the defects.
[0063] Furthermore, the core material fracture defect parameters include the diameter φd and the design depth h1. In step S1, it is also necessary to determine the skin thickness h2 applied to the target foam core material specimen 1. In step S22, the preform is peeled off to a thickness of h1-h2 and cut to a diameter of φd, forming the core material fracture interface layer 3.
[0064] Specifically, in this embodiment, the diameter φd and design depth h1 of the core material fracture defect parameters, as well as the skin thickness h2 applied to the target foam core material test block, are first determined. (The skin is formed after the prepreg is cured.) Then, a preformed foam core material 22 with a thickness greater than h1-h2 is selected, and a preformed adhesive film 21 is bonded to the preformed foam core material 22. The two are then bagged and cured to form a preform. Next, the preformed foam core material 22 is peeled off from the surface of the preformed foam core material 22 opposite to the preformed adhesive film 21 until the thickness of the preform is h1-h2. Then, the preform with a thickness of h1-h2 is cut to form a core material fracture interface layer 3 with a cross-sectional dimension of φd. This ensures that after the core material fracture interface layer 3 is placed in the core material fracture interface layer placement groove 11, when the test block adhesive film is laid, the uncured test block adhesive film can flow on the upper surface of the target foam core material test block 1 and the upper surface of the core material fracture interface layer 3. When the prepreg is laid and bagged for curing, most of the test block adhesive film is squeezed between the prepreg and the upper surface of the target foam core material test block 1. After the defect simulation test block 4 is made, the thickness of the test block adhesive film between the core material fracture interface layer 3 and the skin can be ignored, and the upper surface of the core material fracture interface layer 3 can be flush with the upper surface of the adhesive film in the defect simulation test block 4.
[0065] Specifically, the peeling operation can be performed manually using hand tools such as knives, steel sheets, or sandpaper, or mechanically using a vertical peeling machine. Whether using hand tools or mechanical processing, peeling can begin from the surface of the preformed foam core material 22 that is away from the preformed adhesive film 21, and continue until the thickness of the preform is h1-h2.
[0066] Furthermore, such as Figure 6As shown, in this embodiment, in step S1, it is also necessary to determine the thickness h3 of the adhesive film on the target foam core material test block 1. Then, it is determined that the diameter of the core material fracture interface layer placement groove 11 is φd, and the depth is h1-h2-h3. This setting ensures that the diameter of the core material fracture interface layer placement groove 11 in the target foam core material test block 1 is consistent with the diameter of the core material fracture interface layer 3, and that the depth of the core material fracture interface layer placement groove 11 is consistent with the thickness of the foam core material in the core material fracture interface layer 3. This ensures that when the core material fracture interface layer 3 is placed in the core material fracture interface layer placement groove 11, the foam core material of the core material fracture interface layer 3 can be precisely placed within the core material fracture interface layer placement groove 11, simulating the situation where a real foam core material has defects.
[0067] Furthermore, in step S2, after the core material fracture interface layer 3 is fabricated, a quality inspection is performed on the core material fracture interface layer 3. If it passes the inspection, step S3 is executed; if it fails, step S2 is re-executed. This setup ensures the quality of the core material fracture interface layer 3, thereby preventing quality issues with the core material fracture interface layer 3 from affecting the quality and test results of the defect simulation test block 4, ensuring that the obtained defect simulation test block 4 meets expectations.
[0068] Furthermore, when conducting quality inspection on the fractured interface layer 3 of the core material, the inspection methods are optical inspection, X-ray inspection, or ultrasonic inspection.
[0069] Optionally, in this embodiment, after the core material fracture interface layer 3 is fabricated, the optical inspection method is as follows: the appearance of the core material fracture interface layer 3 is observed and inspected using an optical microscope to check for obvious debonding phenomena, such as cracks, waves, etc.
[0070] Optionally, in other embodiments, the quality inspection of the core material fracture interface layer 3 can also be performed using radiographic testing or ultrasonic testing. Specifically, the radiographic testing method is X-ray testing. Specifically, the ultrasonic testing method is phased array ultrasonic testing.
[0071] Only after the core material fractures and the interface layer 3 meets the requirements will it be processed according to... Figure 7 The core material fracture interface layer 3 is placed in the core material fracture interface layer placement groove 11, and after the test block adhesive film and prepreg are laid on it, it is bagged and cured again to form a defect simulation test block 4. Specifically, the test block adhesive film and prepreg are laid on the entire upper surface of the target foam core material test block 1, and the test block adhesive film and prepreg are laid on the entire lower surface of the target foam core material test block 1. Then, the whole thing is bagged and cured, and after curing, a defect simulation test block 4 is formed.
[0072] Further, steps S1-S4 are repeated to create multiple defect simulation test blocks 4 of different sizes. By creating multiple defect simulation test blocks 4 of different sizes, detection signals of defect simulation test blocks 4 of different sizes can be obtained. Using the detection signals of defect simulation test blocks 4 of different sizes as the judgment standard, if it is necessary to determine the condition of the core material inside the foam sandwich structure, it is only necessary to detect the foam sandwich structure to obtain the detection signal, and compare the detection signal of the foam sandwich structure with the detection signals of defect simulation test blocks 4 of different sizes, so as to quickly and accurately determine the parameter information of the core material fracture defect of the foam sandwich structure. For example, if the detection signal of the foam sandwich structure is consistent with the detection signal of a certain defect simulation test block 4, it is considered that the core material fracture defect parameter of the foam sandwich structure is consistent with the core material fracture defect parameter of that defect simulation test block 4.
[0073] The present invention also provides a defect simulation test block for core material fracture defects in foam sandwich structures, which is made using the above-mentioned method for manufacturing a simulation test block for core material fracture defects in foam sandwich structures.
[0074] The present invention also provides a method for detecting a simulated test block for core material fracture defects in foam sandwich structures, comprising detecting the above-mentioned defect simulated test block 4 and obtaining the detection signal of the defect simulated test block 4.
[0075] Furthermore, the detection signal is an ultrasonic detection signal, which includes the scattered echo at the rear end of the film echo of the defect simulation test block 4.
[0076] Specifically, in this embodiment, ultrasonic testing signals of the defect simulation test block 4 are obtained using an ultrasonic testing device. During use, the testing probe of the ultrasonic testing device is placed against the outer surface of the defect simulation test block 4 for testing. Utilizing the propagation and reflection characteristics of ultrasound, when a core material fracture defect occurs, the discontinuity of the material prevents the ultrasound from further propagating and scattering into the deeper parts of the foam core material of the defect simulation test block 4, and the scattered echo disappears rapidly.
[0077] Specifically, in this embodiment, a gate for monitoring scattered echoes is added to the rear end of the adhesive film echo of the defect simulation test block 4 within the ultrasonic testing equipment. The gate is a time-window-based processing method; by sampling and analyzing the signal within a certain time window, it can reduce misjudgments and missed detections caused by factors such as noise. When the operator requests the ultrasonic testing equipment to compare and calculate a certain echo, the operator needs to "tell" the equipment which echo to track. The gate is used to lock onto the echo to be tested. The ultrasonic testing equipment processes and calculates the echo within the gate and displays all parameters of the echo in real time. Specifically, as... Figure 8As shown, when performing ultrasonic testing on a foam sandwich structure without core material breakage defects, the material itself has an increasing influence on the scattering and attenuation of ultrasonic energy. As a porous material, the small foam chambers inside the foam core continuously cause the scattering and dissipation of ultrasonic energy, and surface waves, film waves and scattered echoes with gradually decreasing energy amplitudes can be obtained.
[0078] like Figure 9 As shown, when performing ultrasonic testing on a foam sandwich structure with core material breakage defects (i.e., defect simulation test block 4 in this embodiment), the discontinuity of the material will prevent the ultrasonic waves from propagating and scattering deeper into the foam core material, and the scattered echo will disappear quickly.
[0079] Of course, in other embodiments, a gate for monitoring the scattered echo can be added at the rear end of the film echo of the defect simulation test block 4 in the signal processing system that processes the acquired ultrasonic signals.
[0080] The above embodiments merely illustrate the basic principles and characteristics of the present invention. The present invention is not limited to the above embodiments. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for fabricating a defect simulation test block, characterized in that, The defect simulation test block (4) used to prepare the core material fracture defect of the foam sandwich structure includes the following steps: S1. Determine the parameters of core material fracture defects; S2. Based on the core material fracture defect parameters, a core material fracture interface layer (3) is formed, and a core material fracture interface layer placement groove (11) is formed on the target foam core material test block (1). S3. Place the core material fracture interface layer (3) in the core material fracture interface layer placement groove (11); S4. The test block film and prepreg are laid on both the upper and lower surfaces of the target foam core material test block (1), and then bagged and cured to form a defect simulation test block (4). Step S2 includes: S21. Adhere the preformed adhesive film (21) to the preformed foam core material (22) and bag and cure the two to form a preform. S22. Peel the surface of the preformed foam core material (22) away from the preformed adhesive film (21) until the thickness of the preform meets the design requirements, and then cut it to the cross-sectional dimensions to meet the design requirements to form the core material fracture interface layer (3). Alternatively, after cutting the preform to the point where the cross-sectional dimensions of the preform meet the design requirements, peeling operation is performed on the surface of the preform foam core material (22) away from the preform adhesive film (21) until the thickness meets the design requirements, forming the core material fracture interface layer (3).
2. The method for fabricating a defect simulation test block according to claim 1, characterized in that, The core material fracture defect parameters include diameter φd and design depth h1; In 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 step S22, the preform is peeled off to a thickness of h1-h2 and cut into a diameter of φd to form the core material fracture interface layer (3).
3. The method for fabricating a defect simulation test block according to claim 2, 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.
4. The method for fabricating a defect simulation test block according to claim 1, characterized in that, In step S2, after the core material fracture interface layer (3) is manufactured, the core material fracture interface layer (3) is subjected to quality inspection. If it is qualified, step S3 is executed; if it is unqualified, step S2 is executed again.
5. The method for fabricating a defect simulation test block according to claim 4, characterized in that, When performing quality inspection on the core material fracture interface layer (3), the inspection method is optical inspection, X-ray inspection or ultrasonic inspection.
6. The method for fabricating a defect simulation test block according to any one of claims 1-5, characterized in that, Repeat steps S1-S4 to create multiple defect simulation test blocks of different sizes (4).
7. A defect simulation test block, characterized in that, It is made using the method for manufacturing defect simulation test blocks according to any one of claims 1-6.
8. A detection method for defect simulation test blocks, characterized in that, The defect simulation test block (4) is tested to obtain the detection signal of the defect simulation test block (4), and the defect simulation test block (4) is made by the method of manufacturing the defect simulation test block according to any one of claims 1-6.
9. The method for detecting defect simulation test blocks according to claim 8, characterized in that, The detection signal is an ultrasonic detection signal, which includes the scattered echo at the rear end of the film echo of the defect simulation test block (4).