Performance test method for joint of three-dimensional woven annular preform
By performing specific performance test methods at the three-dimensional woven annular prefabricated joints, including reduction, re-flattening, cutting and curing, the problem of difficulty in accurately evaluating the performance of annular member connections in the prior art is solved, and the accurate evaluation and improvement of the performance of annular member is achieved.
Patent Information
- Application Number
- CN202510294081.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-13
- Publication Date
- 2025-07-01
AI Technical Summary
It is difficult for the prior art to accurately evaluate the performance of the three-dimensional woven annular prefabricated body connections. Conventional testing methods are not suitable for annular components, and the performance gap at the overall test connections is easily diluted, resulting in the inability to accurately evaluate the reliability of the components.
A three-dimensional woven annular preform joint performance test method is adopted, including obtaining a woven annular preform sample, reducing and re-flattening, so that the joints overlap and are in the center, cutting and curing along the folding position, and evaluating the performance of the joints by Charpy impact test, hammer drop test, tensile test and three-point bending test.
By adjusting the connection to the center of the prefabricated body, performing performance tests after flattening, cutting and curing, the performance of the annular member can be accurately evaluated, which weakens the slippage of the yarn at the connection by flattening, and improves the credibility and accuracy of the test.
Smart Images
Figure CN120232748A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of three-dimensional woven composites, and specifically to a method for testing the performance of joints of three-dimensional woven annular preforms. Background Art
[0002] With the urgent need for integrated forming of lightweight structural parts in fields such as aerospace and rail transit, annular structural parts, as key load-bearing components of various aerospace vehicles and rail transit tools, have become increasingly important.
[0003] Such structural parts not only need to meet complex load requirements but also take into account the design requirements of lightweight and high performance. Currently, traditional processes are mainly based on layup and winding, and there are obvious limitations in the interlayer performance in the thickness direction. In contrast, carbon fiber three-dimensional fabric integrated forming components can not only achieve the integrity and lightweight of the structure but also significantly improve the strength by optimizing the fabric structure, providing a new solution to meet the impact resistance requirements of annular components under actual working conditions.
[0004] Three-dimensional weaving, with its high weaving efficiency and forming quality, is one of the important forming methods for three-dimensional fabrics. Shuttle three-dimensional weaving equipment usually forms annular fabrics through the integrated process of "flattening - weaving - restoring". Different preforms with different structures and strengths can be formed by designing different process parameters. The joints of the annular samples woven by "flattening - weaving - restoring" have different structures from the overall tissue structure, and their specific performance needs to be focused on. Conventional performance testing methods are not applicable to annular components, and the performance differences of the overall tested joints are easily diluted, resulting in the inability to accurately evaluate the reliability of the components. Summary of the Invention
[0005] Object of the Invention: Aiming at the above-mentioned shortcomings, the present invention provides a method for testing the performance of joints of three-dimensional woven annular preforms to improve the accuracy of component evaluation.
[0006] Technical Solution: To solve the above problems, the present invention adopts a method for testing the performance of joints of three-dimensional woven annular preforms, including the following steps:
[0007] (1) Obtain a flattened-woven annular preform sample, with joints on both sides of the flattened-woven annular preform sample;
[0008] (2) Restore the flattened-woven annular preform sample to an annular shape and then flatten it again. After flattening, the two joints are located at the non-folded positions of the flattened annular preform sample;
[0009] (3) Cut along the folded position of the flattened annular preform sample to obtain a flat preform sample containing the joints;
[0010] (4) Cure the flat preform specimen, and conduct performance tests on the joints after curing.
[0011] Furthermore, for the annular preform specimen that is flattened after reduction in step (2), after flattening, the two joints coincide, and both joints are located at the center of the flattened annular preform specimen.
[0012] Furthermore, the performance tests include Charpy impact test, drop weight impact test, tensile test, and three-point bending test.
[0013] Furthermore, in step (1), first determine the dimensions of the standard specimen for the performance test, including the thickness and length of the standard prototype. Determine the thickness of the annular preform specimen according to the thickness of the standard specimen, determine the diameter of the corresponding annular target component according to the length of the standard specimen, and determine the diameter of the annular preform specimen according to the diameter of the target component.
[0014] Furthermore, the diameter of the annular preform specimen is greater than the diameter of the target component.
[0015] Furthermore, after restoring the flattened woven annular preform specimen to an annular shape in step (2), align the two joints of the annular preform specimen vertically in the center, and then flatten it with two metal plates on the top and bottom.
[0016] Furthermore, ensure that the cut is smooth during cutting to avoid burrs or unevenness.
[0017] Furthermore, when curing the flat preform specimen in step (4), face the inner side of the flat preform specimen towards the curing glass bottom plate, and place weights on the vacuum bag at the joint position to continuously press. The inner side of the flat preform specimen is the inner side of the annular preform specimen during flattening and weaving.
[0018] Advantageous effects: Compared with the prior art, the significant advantage of the present invention is that the joints of the annular preform are adjusted to the center of the preform, cut after flattening, weakening the slip phenomenon of the preform yarns on both sides of the joint during flattening. After cutting and curing, the performance of the joints of the specimen is evaluated through performance tests, thereby achieving an accurate evaluation of the overall performance of the annular component. Description of the Drawings
[0019] Figure 1 It is a flow schematic diagram of the performance test method of the present invention.
[0020] Figure 2 It is a principle schematic diagram of the performance test method of the present invention. Detailed Embodiments
[0021] Such as Figure 1As shown, a three-dimensional woven annular preform connection performance test method in this embodiment includes the following steps:
[0022] (1) Obtain a flattened woven annular preform specimen, with the two sides of the flattened woven annular preform specimen being the connection points. The thickness of the annular preform needs to be designed according to the specific test standard specimen to ensure that the thickness of the final specimen meets the standard, and the thickness of the final specimen cannot be adjusted by grinding or milling. The key to this step is accurate calculation and strict control to ensure that the mechanical properties and dimensional accuracy of the specimen meet the requirements of subsequent testing and application. The thickness of the test specimen determines the length of the specimen, and the length of the specimen is used as the minimum target value to arrange the diameter of the annular preform specimen.
[0023] First determine the size of the standard sample for the performance test, including the thickness and length of the standard sample. Determine the thickness of the annular preform specimen according to the thickness of the standard sample. Determine the diameter of the corresponding annular target component according to the length of the standard sample. Determine the diameter of the annular preform specimen according to the diameter of the target component. The diameter of the annular preform is selected to leave enough margin for cutting according to the required size of the sample. The diameter of the annular preform specimen is larger than the diameter of the target component. The preform diameter is appropriately adjusted according to the ratio of the determined sample thickness to the target component to ensure the geometric shape and dimensional accuracy of the final component.
[0024] (2) The flattened woven annular preform sample is restored to an annular state and then flattened again. After flattening, the two joints overlap and are located at the center of the flattened annular preform sample. This operation helps to ensure symmetry and consistency during subsequent cutting, facilitates size control, and makes cutting more convenient. Flattening can be performed using two metal plates.
[0025] (3) Cut along the folded position of the flattened annular preform sample to obtain a flat preform sample including the joint; ensure that the cut is smooth during cutting to avoid burrs or unevenness to ensure accuracy and reliability during subsequent assembly or testing. The slippage of the yarns on both sides of the joint due to flattening will be weakened in the entire preform when the annular preform sample is flattened first, compared to flattening after cutting, thereby improving the test credibility of the sample.
[0026] (4) The flat plate preform specimen is cured, and after curing, the joint is subjected to performance tests, including Charpy impact test, drop weight test, tensile test and three-point bending test. When curing the flat plate preform specimen, the inner side of the flat plate preform specimen is directed toward the curing glass bottom plate, and a heavy object is placed on the vacuum bag at the joint position to continuously press it. The inner side of the flat plate preform specimen is the inner side of the annular preform specimen during flattening and weaving.
[0027] Adjust the connection of the annular preform to the center of the preform, flatten, cut, and cure it, and then evaluate the impact resistance performance of the connection of the sample through the Charpy impact test. This simplifies the impact performance of the connection that was originally difficult to characterize, facilitates highlighting the differences in the performance of the connection under different process parameters, and is easy to optimize the process parameters according to the performance requirements.
Claims
1. A method for testing the performance of a three-dimensional woven annular preform connection, characterized in that: The following steps are involved: (1) obtaining a flattened woven annular preform sample, wherein two sides of the flattened woven annular preform sample are connected; (2) restoring the flattened woven annular preform sample to a ring shape and then flattening it again, wherein the two connecting portions after flattening are located at non-folded positions of the flattened annular preform sample; (3) cutting along the folding position of the flattened annular preform sample to obtain a flat preform sample including the connection; (4) Curing the flat plate preform specimens, and performing performance tests on the joints after curing.
2. The three-dimensional woven annular preform connection performance test method according to claim 1, characterized in that: In the step (2), the annular preform sample is flattened after reduction, and the two connection points overlap after flattening, and the two connection points are both located at the center of the flattened annular preform sample.
3. The three-dimensional woven annular preform connection performance test method according to claim 2, characterized in that: The performance tests include a Charpy impact test, a drop weight impact test, a tensile test and a three-point bending test.
4. The three-dimensional woven annular preform connection performance test method according to claim 1, characterized in that: In the step (1), the size of the standard sample for the performance test is first determined, including the thickness and length of the standard sample. The thickness of the annular preform sample is determined according to the thickness of the standard sample. The diameter of the corresponding annular target component is determined according to the length of the standard sample. The diameter of the annular preform sample is determined according to the diameter of the target component.
5. The method for testing the joint performance of a three-dimensional woven annular preform according to claim 4, characterized in that: The diameter of the annular preform sample is greater than the diameter of the target component.
6. The three-dimensional woven annular preform connection performance test method according to claim 2, characterized in that: After the flattened woven annular preform sample is restored to a ring shape in the step (2), the two connecting parts of the annular preform sample are aligned in the center along the vertical direction, and then flattened by upper and lower metal plates.
7. The three-dimensional woven annular preform connection performance test method according to claim 1, characterized in that: When cutting, make sure the cut is smooth to avoid burrs or unevenness.
8. The method for testing the joint performance of a three-dimensional woven annular preform according to claim 7, characterized in that: When the flat preform sample is cured in the step (4), the inner side of the flat preform sample is oriented toward the curing glass bottom plate, and a heavy object is placed on the vacuum bag at the connection position to continuously press it. The inner side of the flat preform sample is the inner side of the annular preform sample during flattening and weaving.