Sample preparation tool for I-type fracture toughness test
By designing a sample preparation fixture for Type I fracture toughness testing, the problems of difficult film positioning and large data dispersion were solved, thereby improving the accuracy and efficiency of the test and ensuring the consistency of sample quality and the reliability of test data.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-22
- Publication Date
- 2026-04-14
AI Technical Summary
Traditional sample preparation methods are difficult to position the film, which causes cracks to propagate outside the centerline of the adhesive layer, affecting the accuracy of the test; the data dispersion is large, the sample qualification rate is low, and it is difficult to meet the standard accuracy requirements.
A sample preparation fixture for Type I fracture toughness testing was designed, comprising a platform, a substrate limiting mechanism, a film fixing mechanism, and a substrate clamping mechanism, to ensure accurate film positioning and uniform adhesive layer thickness. The modular design simplifies the operation process.
It improves test accuracy, reduces sample rejection rate, enhances sample preparation efficiency and sample quality consistency, and ensures the reliability of test data.
Smart Images
Figure CN224122270U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of composite material performance testing technology, specifically relating to a sample preparation tool for type I fracture toughness testing. Background Technology
[0002] Fiber-reinforced composites are currently considered the only structural materials capable of solving infrastructure corrosion problems and achieving long service life and high performance, leading to their rapid development in the automotive, aerospace, and wind power industries. Simultaneously, with the continuous expansion of the composite materials field, the application range of composite materials is also constantly expanding. The Type I fracture toughness test for composite materials is a mechanical testing method used to measure the material's resistance to crack propagation perpendicular to the crack plane. It typically uses a double cantilever beam (DCB) specimen and is performed according to ASTM D5528. Type I fracture toughness is a crucial indicator for composite materials. The test results are essential for evaluating the structural integrity of composite materials in aerospace, automotive, and other fields, especially under conditions requiring fatigue loading or environmental corrosion. Type I fracture toughness data can be directly used for safety design, life estimation, and defect assessment.
[0003] In composite material testing, Type I fracture toughness is determined using a double cantilever beam (DCB) specimen. Tensile loads are applied to induce crack propagation along the interlaminar interface, and the relationship between the load and crack propagation length is recorded. In Type I fracture toughness testing, a non-adhesive thin film needs to be pre-embedded in the middle of the adhesive layer to pre-initiate the crack. However, traditional sample preparation methods have the following problems: 1. Difficulty in film positioning: The pre-embedded film is prone to displacement, causing crack propagation to deviate from the centerline of the adhesive layer, affecting test accuracy; 2. Large data dispersion: Due to inconsistent crack initiation positions, test results are difficult to meet the accuracy requirements of the standard; 3. Low specimen pass rate: Manual operation makes it difficult to ensure the film is centered, resulting in a high specimen scrap rate and affecting testing efficiency. Utility Model Content
[0004] The technical problem solved by this utility model is to provide a sample preparation tool for type I fracture toughness testing, which can ensure accurate film position and accurate and uniform adhesive layer thickness in the sample, and the tool is simple to operate and has high sample preparation efficiency.
[0005] To address the aforementioned problems, this utility model provides a sample preparation fixture for Type I fracture toughness testing, comprising:
[0006] Platform; the upper surface of the platform is horizontal and used to place the lower substrate.
[0007] Substrate limiting mechanism; disposed on the upper surface of the platform, used to limit the ends of the lower substrate and the upper substrate after they are stacked, and to restrict the horizontal displacement of the lower substrate and the upper substrate;
[0008] A film fixing mechanism includes a first gasket, a second gasket, and a gasket pressing part; the first gasket is disposed on the upper surface of the platform, and the thickness of the first gasket is the same as the thickness of the lower substrate located at the bottom; the second gasket is disposed on the first gasket, and the thickness of the second gasket is the same as the thickness of the adhesive layer between the lower substrate and the film; the gasket pressing part is used to press the second gasket and the first gasket to the upper surface of the platform.
[0009] Preferably, it further includes:
[0010] A substrate clamping mechanism is used to clamp and fix the upper substrate located at the top to the platform.
[0011] Preferably, it further includes:
[0012] A thickness pad is disposed between the lower substrate and the upper substrate, and located below the position where the substrate clamping mechanism contacts the upper substrate; the thickness of the thickness pad is the same as the total thickness of the adhesive layer between the lower substrate and the upper substrate.
[0013] Preferably, a row of substrate clamping mechanisms is provided on each side of the upper substrate; each row includes multiple substrate clamping mechanisms.
[0014] Preferably, the substrate limiting mechanism includes:
[0015] A limiting block is disposed on the upper surface of the platform, and the inner side of the limiting block is flush with the end faces of the lower substrate and the upper substrate.
[0016] The first positioning screw is used to detachably connect the limiting block to the platform.
[0017] Preferably, the gasket clamping part includes:
[0018] A pressure block, wherein the pressure block is disposed on the second gasket;
[0019] A pressure block fixing part; the pressure block fixing part is used to fix the pressure block to the platform.
[0020] Preferably, the pressure block fixing part is a second positioning screw.
[0021] Preferably, there are two film fixing mechanisms, which are disposed on the upper surface of the platform and located on both sides of the lower substrate.
[0022] Preferably, the substrate clamping mechanism is an F-clamp, the fixed arm of the F-clamp is located at the bottom of the platform, and the movable arm of the F-clamp presses against the upper surface of the upper substrate.
[0023] Preferably, the bottom of the platform is provided with a groove, in which the fixing arm of the F clamp is adapted to be placed.
[0024] Compared with the prior art, this utility model has the following advantages:
[0025] This utility model provides a sample preparation fixture for Type I fracture toughness testing. Through a substrate limiting mechanism, it ensures that the upper and lower substrates do not shift. The first and second gaskets control the adhesive layer thickness and film position, preventing film displacement and improving test accuracy. The fixture employs a modular design, simplifying the process and improving work efficiency. It also boasts high stability, good sample quality consistency, and more reliable test data. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the sample preparation tool for type I fracture toughness testing as described in an embodiment of this utility model;
[0027] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle.
[0028] Wherein: 1-platform; 2-lower substrate; 3-upper substrate; 4-first gasket; 5-second gasket; 6-substrate clamping mechanism; 7-limiting block; 8-first positioning screw; 9-pressure block; 10-pressure block fixing part; 11-groove. Detailed Implementation
[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0030] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and 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 this utility model.
[0031] Example 1
[0032] like Figure 1 , Figure 2 As shown, a sample preparation fixture for type I fracture toughness testing according to this embodiment includes:
[0033] Platform 1; The upper surface of platform 1 is horizontal and used to place the lower substrate 2;
[0034] Substrate limiting mechanism; located on the upper surface of platform 1, used to limit the ends of the lower substrate 2 and upper substrate 3 after being stacked, and to restrict the horizontal displacement of the lower substrate 2 and upper substrate 3.
[0035] The film fixing mechanism includes a first gasket 4, a second gasket 5, and a gasket pressing part; the first gasket 4 is disposed on the upper surface of the platform 1, and the thickness of the first gasket 4 is the same as the thickness of the lower substrate 2 located at the bottom; the second gasket 5 is disposed on the first gasket 4, and the thickness of the second gasket 5 is the same as the thickness of the adhesive layer between the lower substrate 2 and the film; the gasket pressing part is used to press the second gasket 5 and the first gasket 4 to the upper surface of the platform 1.
[0036] The sample preparation fixture for Type I fracture toughness testing in this embodiment has the following steps: First, fix the substrate limiting mechanism on the platform to limit the displacement of the substrate; evenly apply a release agent to the upper surface of the platform to facilitate subsequent demolding; place the lower substrate 2 flat on the platform, place the first gasket 4 on the platform, with the upper surface of the first gasket flush with the upper surface of the lower substrate; select the thickness of the second gasket 5 according to the target adhesive layer thickness, for example, if the total thickness of the target adhesive layer is 3mm, then the second gasket 5 is a 1.5mm thick gasket; evenly apply the adhesive to the upper surface of the lower substrate with a thickness of 1.5mm; place the cut film on the second gasket, and fix the first and second gaskets with the gasket clamping part; cover the other side of the film with the adhesive layer, apply adhesive again to the film, and cover the upper substrate; place the entire fixture in an oven for curing, and after completion, remove the sample and process it into a specimen for mechanical testing.
[0037] The sample preparation fixture for Type I fracture toughness testing in this embodiment ensures that the upper and lower substrates do not shift through a substrate limiting mechanism; the thickness of the adhesive layer and the position of the film are controlled by the first and second shims to prevent film displacement and improve test accuracy; the modular design simplifies the process and improves work efficiency; the fixture has high stability, good sample quality consistency, and more reliable test data.
[0038] Preferably, the sample preparation fixture for type I fracture toughness testing further includes:
[0039] The substrate clamping mechanism 6 is used to clamp and fix the upper substrate 3 located at the top to the platform 1.
[0040] The substrate clamping mechanism 6 can clamp and fix the upper substrate 3 to the platform 1 to ensure that the total thickness of the adhesive layer is accurate and uniform.
[0041] Preferably, the sample preparation fixture for type I fracture toughness testing further includes:
[0042] A thickness pad is placed between the lower substrate 2 and the upper substrate 3, and is located below the contact point between the substrate clamping mechanism 6 and the upper substrate 3. The thickness of the thickness pad is the same as the total thickness of the adhesive layer between the lower substrate 2 and the upper substrate 3. The thickness pad works in conjunction with the substrate clamping mechanism to further ensure the accuracy and uniformity of the total thickness of the adhesive layer between the upper and lower substrates.
[0043] Preferably, a row of substrate clamping mechanisms is provided on each side of the upper substrate 3; each row includes multiple substrate clamping mechanisms. Correspondingly, there are multiple thickness pads, and a thickness pad is provided below each substrate clamping mechanism in contact with the upper substrate between the lower substrate 2 and the upper substrate 3. The thickness of the thickness pad is the total thickness of the adhesive layer. The cooperation of multiple substrate clamping mechanisms and thickness pads can ensure a more uniform adhesive layer thickness between the two substrates.
[0044] Preferably, the substrate limiting mechanism includes:
[0045] The limiting block 7 is located on the upper surface of the platform 1, and the inner side of the limiting block 7 is flush with the end faces of the lower substrate 2 and the upper substrate 3.
[0046] The first positioning screw 8 is used to detachably connect the limiting block 7 to the platform 1.
[0047] Preferably, the gasket clamping part includes:
[0048] Pressure block 9, which is located on the second pad 5;
[0049] Pressure block fixing part 10; Pressure block fixing part 10 is used to fix the pressure block to the platform.
[0050] Preferably, the pressure block fixing part is a second positioning screw.
[0051] Preferably, there are two film fixing mechanisms, which are disposed on the upper surface of platform 1 and located on both sides of the lower substrate. The film fixing mechanisms on both sides fix the two ends of the film, ensuring that the film is accurately positioned and fixed.
[0052] Preferably, the substrate clamping mechanism is an F-clamp, with the fixed arm of the F-clamp located at the bottom of the platform and the movable arm of the F-clamp pressing against the upper surface of the upper substrate. Using an F-clamp makes it easier to fix the substrate to the platform and facilitates disassembly.
[0053] Preferably, the bottom of the platform 1 is provided with a groove 11, and the groove 11 is suitable for placing the fixing arm of the F clamp.
[0054] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.
Claims
1. A sample preparation fixture for type I fracture toughness testing, characterized in that, include: Platform; the upper surface of the platform is horizontal and used to place the lower substrate. Substrate limiting mechanism; It is disposed on the upper surface of the platform and is used to limit the ends of the lower substrate and the upper substrate after they are stacked, thereby restricting the displacement of the lower substrate and the upper substrate in the horizontal direction. A film fixing mechanism includes a first gasket, a second gasket, and a gasket pressing part; the first gasket is disposed on the upper surface of the platform, and the thickness of the first gasket is the same as the thickness of the lower substrate located at the bottom; the second gasket is disposed on the first gasket, and the thickness of the second gasket is the same as the thickness of the adhesive layer between the lower substrate and the film; the gasket pressing part is used to press the second gasket and the first gasket to the upper surface of the platform.
2. The sample preparation fixture for type I fracture toughness testing according to claim 1, characterized in that, Also includes: A substrate clamping mechanism is used to clamp and fix the upper substrate located at the top to the platform.
3. The sample preparation fixture for type I fracture toughness testing according to claim 2, characterized in that, Also includes: A thickness pad is disposed between the lower substrate and the upper substrate, and located below the position where the substrate clamping mechanism contacts the upper substrate; the thickness of the thickness pad is the same as the total thickness of the adhesive layer between the lower substrate and the upper substrate.
4. The sample preparation fixture for type I fracture toughness testing according to claim 2, characterized in that: The upper substrate has a row of substrate clamping mechanisms on each side; each row includes multiple substrate clamping mechanisms.
5. The sample preparation fixture for type I fracture toughness testing according to claim 1, characterized in that, The substrate limiting mechanism includes: A limiting block is disposed on the upper surface of the platform, and the inner side of the limiting block is flush with the end faces of the lower substrate and the upper substrate. The first positioning screw is used to detachably connect the limiting block to the platform.
6. The sample preparation fixture for type I fracture toughness testing according to claim 1, characterized in that, The gasket clamping part includes: A pressure block, wherein the pressure block is disposed on the second gasket; A pressure block fixing part; the pressure block fixing part is used to fix the pressure block to the platform.
7. The sample preparation fixture for type I fracture toughness testing according to claim 6, characterized in that: The pressure block fixing part is the second positioning screw.
8. The sample preparation fixture for type I fracture toughness testing according to claim 1, characterized in that: There are two film fixing mechanisms, which are disposed on the upper surface of the platform and located on both sides of the lower substrate.
9. The sample preparation fixture for type I fracture toughness testing according to claim 2, characterized in that: The substrate clamping mechanism is an F-clamp, with the fixed arm of the F-clamp located at the bottom of the platform and the movable arm of the F-clamp pressing against the upper surface of the upper substrate.
10. The sample preparation fixture for type I fracture toughness testing according to claim 9, characterized in that: The bottom of the platform is provided with a groove, in which the fixing arm of the F clamp is adapted to be placed.