A composite material v-notch specimen shearing test fixture

Abstract

The utility model discloses a kind of composite V-shaped gap piece shearing test fixture, including first fixture, first fixture side is equipped with second fixture, first fixture and second fixture are connected with centering mechanism in middle, centering mechanism includes the wedge-shaped slot in the inner surface of first fixture and second fixture, wedge-shaped block is slidably connected in wedge-shaped slot, wedge-shaped block is connected with support frame, two centering blocks are symmetrically provided in support frame, recess is equipped in support frame side, bidirectional screw rod is equipped in recess, sliding block is threadedly connected on bidirectional screw rod, sliding block is connected with centering block, the utility model is accurate to adjust the relative position between first fixture and second fixture by setting centering mechanism, rotating bidirectional screw rod can drive two sliding blocks synchronous reverse movement, to drive two sides centering block synchronous adjustment, promote wedge-shaped block to slide in wedge-shaped slot, to accurately adjust the relative position between first fixture and second fixture. The structure realizes real-time, symmetry, accurate centering in the process of sample clamping.

Description

Technical Field

[0001] This utility model relates to the field of composite material strength testing technology, specifically to a composite material V-notch shear test fixture. Background Technology

[0002] In actual service, composite structural components often endure complex loads, among which shear load is a significant factor leading to damage modes such as material delamination and matrix cracking. Therefore, accurately assessing the interlaminar shear properties and in-plane shear strength of composite materials is crucial for structural design, safety verification, and life prediction. Currently, testing methods for the shear properties of composite materials mainly include short beam shear tests, Iosipescu shear tests, and V-notched beam (VNB) shear tests. Among these, the V-notched shear test, by pre-fabricating a V-shaped notch in the middle of the specimen, concentrates stress in the notch root region, thereby forming a more uniform shear stress field during loading. This more realistically reflects the failure mechanism of materials under shear-dominated conditions and is particularly suitable for evaluating the shear strength and fracture toughness of materials.

[0003] In actual testing, the design of the fixture has a decisive impact on the accuracy and reliability of the test results. Traditional shear fixtures generally suffer from problems such as difficulty in specimen centering, load eccentricity, and uneven stress distribution, which can easily lead to unexpected failure of the specimen in the clamping area (such as crushing, splitting, or bending failure), thus affecting the validity of the test data. Utility Model Content

[0004] In view of the problems in the related technologies, this utility model proposes a composite material V-notch shear test fixture to overcome the above-mentioned technical problems existing in the existing related technologies.

[0005] Therefore, the specific technical solution adopted by this utility model is as follows:

[0006] A shear test fixture for a composite material V-notch component includes a first fixture, a second fixture on one side of the first fixture, and a centering mechanism connected between the first and second fixtures. The centering mechanism includes a wedge-shaped groove on the inner surface of the first and second fixtures, a wedge-shaped block slidably connected inside the wedge-shaped groove, the wedge-shaped block being connected to a support frame, two centering blocks symmetrically arranged inside the support frame, a groove on one side of the support frame, a bidirectional threaded rod inside the groove, a slider threadedly connected to the bidirectional threaded rod, and the slider being connected to the centering block.

[0007] Furthermore, both ends of the bidirectional threaded rod are connected to the support frame via bearings.

[0008] Furthermore, a driven bevel gear is connected at the middle position of the bidirectional threaded rod. The driven bevel gear meshes with the driving bevel gear. One side of the driving bevel gear is connected to the rotating rod, and the rotating rod is connected to the fixed frame through a bearing.

[0009] Furthermore, the fixed frame is connected to the support frame, and one end of the rotating rod passes through the fixed frame and is connected to the rotating plate.

[0010] Furthermore, the first and second clamps are provided with placement slots, and two clamping plates are symmetrically arranged inside the placement slots. A first locking bolt is connected to one side of the clamping plate via a bearing. The first and second clamps are provided with first threaded holes, and the first locking bolt matches the first threaded hole.

[0011] Furthermore, second locking bolts are provided on both sides of the first locking bolt, and second threaded holes are provided on the first and second clamps, which are matched with the second locking bolts.

[0012] Furthermore, the second locking bolt abuts against the clamping plate.

[0013] Furthermore, a connector is connected to one side of the first clamp and the second clamp, and the connector is provided with a mounting hole.

[0014] The beneficial effects of this utility model are as follows:

[0015] By setting up a linkage centering mechanism consisting of a bidirectional threaded rod, sliders, centering blocks, wedge blocks, and wedge grooves, rotating the bidirectional threaded rod drives the two sliders to move synchronously in opposite directions, thereby driving the centering blocks on both sides to adjust synchronously and pushing the wedge blocks to slide within the wedge grooves, thus precisely adjusting the relative position between the first and second clamps. This structure achieves real-time, symmetrical, and precise centering during sample clamping, effectively avoiding additional bending stress caused by eccentric loading, ensuring that shear stress is concentrated at the root of the V-notch, and significantly improving the accuracy and reliability of test data. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a front view of a composite material V-notch shear test fixture according to an embodiment of the present utility model;

[0018] Figure 2 This is a diagram of the centering mechanism of a composite material V-notch shear test fixture according to an embodiment of the present utility model;

[0019] Figure 3 This is a structural diagram of a composite material V-notch shear test fixture support frame according to an embodiment of the present utility model;

[0020] Figure 4 This is a rear view of a composite material V-notch shear test fixture support frame according to an embodiment of the present utility model;

[0021] Figure 5 This is a structural diagram of the internal groove of a composite material V-notch shear test fixture according to an embodiment of the present utility model.

[0022] In the picture:

[0023] 1. First clamp; 2. Second clamp; 3. Centering mechanism; 301. Wedge groove; 302. Wedge block; 303. Support frame; 304. Centering block; 305. Groove; 306. Bidirectional threaded rod; 307. Slider; 4. Driven bevel gear; 5. Driving bevel gear; 6. Rotating rod; 7. Fixing frame; 8. Rotating plate; 9. Placement slot; 10. Clamping plate; 11. First locking bolt; 12. First threaded hole; 13. Second locking bolt; 14. Second threaded hole; 15. Connector; 16. Mounting hole. Detailed Implementation

[0024] 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.

[0025] According to an embodiment of the present invention, a shear test fixture for composite material V-notch members is provided.

[0026] like Figures 1-5As shown, the composite material V-notch shear test fixture according to an embodiment of the present invention includes a first fixture 1, a second fixture 2 on one side of the first fixture 1, and a centering mechanism 3 connected between the first fixture 1 and the second fixture 2. The centering mechanism 3 includes a wedge-shaped groove 301 disposed on the inner surface of the first fixture 1 and the second fixture 2, a wedge-shaped block 302 slidably connected inside the wedge-shaped groove 301, and the wedge-shaped block 302 connected to the support frame 303. By installing the wedge-shaped block 302 on the surface of the fixture, the centering block 304 is positioned at the center of the fixture. Two centering blocks 304 are symmetrically arranged inside the support frame 303. A groove 305 is provided on one side of the support frame 303, and a bidirectional screw is provided inside the groove 305. The threaded rod 306 has a slider 307 threadedly connected to it. The slider 307 is connected to the centering block 304. Both ends of the threaded rod 306 are connected to the support frame 303 through bearings. A driven bevel gear 4 is connected to the middle of the threaded rod 306. The driven bevel gear 4 meshes with the driving bevel gear 5. One side of the driving bevel gear 5 is connected to the rotating rod 6. The rotating rod 6 is connected to the fixed frame 7 through bearings. The fixed frame 7 is connected to the support frame 303. One end of the rotating rod 6 passes through the fixed frame 7 and is connected to the rotating plate 8. By rotating the rotating plate 8, the centering block 304 is driven to move down, so that the centering block 304 contacts the V-shaped notch in the V-shaped notch part, thus achieving the centering of the V-shaped notch part.

[0027] like Figures 1-4 As shown, the first clamp 1 and the second clamp 2 have placement grooves 9 inside for accommodating the composite material V-notch specimen to be tested. Two clamping plates 10 are symmetrically arranged inside the placement grooves 9. The function of the clamping plates 10 is to directly contact the specimen and apply clamping force to prevent the specimen from sliding or misaligning during shear loading. A first locking bolt 11 is connected to one side of the clamping plate 10 via a bearing. The first clamp 1 and the second clamp 2 have first threaded holes 12. The first locking bolt 11 matches the first threaded hole 12. When the first locking bolt 11 is rotated, the clamping plate 10 will not rotate with the bolt, but will move smoothly along the axial direction. To achieve uniform clamping of the sample and avoid scratches or stress concentration on the sample surface caused by direct friction of the bolts, second locking bolts 13 are provided on both sides of the first locking bolt 11. Second threaded holes 14 are provided on the first clamp 1 and the second clamp 2, matching the second locking bolts 13. The second locking bolts 13 abut against the clamping plate 10. After the first locking bolt 11 is adjusted to the correct position and clamps the sample, the second locking bolts 13 are tightened so that their ends abut against the clamping plate 10, thereby limiting the slight displacement or rebound of the clamping plate 10 during the test and effectively preventing the clamping force from loosening due to vibration or load fluctuations. Connecting parts 15 are connected to one side of the first clamp 1 and the second clamp 2 for installing the entire clamp system onto the upper and lower loading beams of the universal testing machine. The connecting parts 15 have mounting holes 16 for inserting bolts or pins, enabling quick installation and fixation of the clamps to the loading head of the testing machine.

[0028] In practical use, the V-notch sample of the composite material to be tested is first placed in the placement groove 9 of the first fixture 1. Then, the support frame 303 is installed on the first fixture 1 by means of the wedge block 302. The support frame 303 is fixed by means of ... The movement of the centering block 304 causes the connected wedge block 302 to slide in the wedge groove 301 on the inner surface of the first clamp 1 and the second clamp 2, thereby adjusting the relative position between the first clamp 1 and the second clamp 2 and achieving precise centering of the entire clamping system relative to the V-notch of the specimen. When the centering block 304 moves down and contacts the notch edge of the V-notch specimen, it can be determined that the specimen is in an ideal centering state. At this time, the loading axis is completely coincident with the geometric center of the specimen, which can effectively avoid the additional bending moment caused by eccentric loading. Then, the first locking bolt 11 is rotated manually or with a tool. Since it is connected to the clamping plate 10 through a bearing, the clamping plate 10 will not rotate with it during the rotation, but will move smoothly towards the specimen along the bolt axis, achieving uniform clamping of the specimen. When the clamping force reaches the predetermined value, the rotation of the first locking bolt 11 is stopped. To further ensure the stability of the clamping and prevent the clamping from loosening due to vibration or load changes during subsequent loading, the operator continues to tighten the second locking bolts 13 located on both sides of the first locking bolt 11. The second locking bolt 13 passes through the second threaded hole 14 on the fixture and its end abuts tightly against the side of the clamping plate 10 to form a mechanical limit, effectively locking the position of the clamping plate 10 and fixing the sample in the first fixture 1. Then, by moving the support frame 303 in the sample thickness direction, the support frame 303 is disassembled. Then, by installing the support frame 303 on the second fixture 2 and adjusting the position of the second fixture 2 so that the centering block 304 contacts the notch edge of the V-notch sample, the sample is fixed in the second fixture 2 by rotating the first locking bolt 11 and the second locking bolt 13 on the outside of the second fixture 2. Then, by disassembling the support frame 303 and assembling the test fixture and the sample, the fixture is connected to the testing machine through the connector 15, and the shear test can be performed.

[0029] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A shear test fixture for a composite material V-notch component, characterized in that, The first clamp (1) is provided with a second clamp (2) on one side of the first clamp (1). A centering mechanism (3) is connected between the first clamp (1) and the second clamp (2). The centering mechanism (3) includes a wedge groove (301) provided on the inner surface of the first clamp (1) and the second clamp (2). A wedge block (302) is slidably connected inside the wedge groove (301). The wedge block (302) is connected to the support frame (303). Two centering blocks (304) are symmetrically arranged inside the support frame (303). A groove (305) is provided on one side of the support frame (303). A bidirectional threaded rod (306) is provided inside the groove (305). A slider (307) is threadedly connected to the bidirectional threaded rod (306). The slider (307) is connected to the centering block (304).

2. The composite material V-notch shear test fixture according to claim 1, characterized in that, The two ends of the bidirectional threaded rod (306) are connected to the support frame (303) via bearings.

3. The composite material V-notch shear test fixture according to claim 1, characterized in that, A driven bevel gear (4) is connected in the middle of the double-threaded rod (306). The driven bevel gear (4) meshes with the driving bevel gear (5). One side of the driving bevel gear (5) is connected to the rotating rod (6). The rotating rod (6) is connected to the fixed frame (7) through a bearing.

4. The composite material V-notch shear test fixture according to claim 1, characterized in that, The fixed frame (7) is connected to the support frame (303), and one end of the rotating rod (6) passes through the fixed frame (7) and is connected to the rotating plate (8).

5. A composite material V-notch shear test fixture according to claim 1, characterized in that, The first clamp (1) and the second clamp (2) are provided with a placement groove (9). Two clamping plates (10) are symmetrically arranged inside the placement groove (9). A first locking bolt (11) is connected to one side of the clamping plate (10) through a bearing. The first clamp (1) and the second clamp (2) are provided with a first threaded hole (12). The first locking bolt (11) matches the first threaded hole (12).

6. A composite material V-notch shear test fixture according to claim 1, characterized in that, The first locking bolt (11) has a second locking bolt (13) on both sides. The first clamp (1) and the second clamp (2) have a second threaded hole (14) that matches the second locking bolt (13).

7. A composite material V-notch shear test fixture according to claim 1, characterized in that, The second locking bolt (13) abuts against the clamping plate (10).

8. A composite material V-notch shear test fixture according to claim 1, characterized in that, The first clamp (1) and the second clamp (2) are connected to a connector (15) on one side, and the connector (15) is provided with a mounting hole (16).

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