Composite material flat plate tensile test automatic clamping and centering mechanism

Abstract

The application belongs to the field of aircraft structure strength test, and particularly relates to a composite material flat plate tensile test automatic clamping and centering mechanism. The mechanism comprises an L-shaped base (1) and a connecting rod mechanism. The L-shaped base (1) is provided with two symmetrical transverse strip holes (13) relative to a central axis and a vertical strip hole (14) on the central axis. The connecting rod mechanism comprises two connecting rods, one end of each of the two connecting rods is hinged through a pin (9), the pin (9) slides in the vertical strip hole (14), the other end of each of the two connecting rods is connected with a sliding block, the two sliding blocks slide in the two transverse strip holes (13) respectively and form clamping protrusions for clamping test pieces, and one of the sliding blocks is connected with a spring connecting rod (6) on the L-shaped base (1) through a tension spring (7). The application solves the problem of difficult adjustment of the limiting strip when the test is performed in a high-low temperature environment box, saves test time and improves test efficiency.

Description

Technical Field

[0001] This application belongs to the field of aircraft structural strength testing, and specifically relates to an automatic clamping and centering mechanism for tensile testing of composite material plates. Background Technology

[0002] Composite material mechanical property testing is the most fundamental test at the base of the aircraft strength testing pyramid. Due to continuous material iteration and updates, and the increasing proportion of composite materials in domestically produced aircraft, a large number of basic tests are required annually to evaluate and verify the basic properties of materials. The plate tensile test is the most common type of test in composite material mechanical property testing. The test is conducted on a standard testing machine and held by a standard test specimen clamp. Because the width of the test specimen varies in standards for testing different material properties (ranging from 15mm to 38mm), to prevent premature failure due to eccentric loading, the center of the specimen in the width direction must be aligned with the center of the test specimen clamp before clamping. Currently, the common method is to loosen the fasteners and adjust the position of the limiting strip before testing, ensuring the specimen is centered in the width direction of the clamp before clamping. Since the specimen width may vary with each test, the position of the limiting strip must be constantly adjusted. This is particularly problematic during high and low temperature environments, where personnel must visually inspect the test chamber, making adjustments to the limiting strip after changes in specimen width inconvenient. Summary of the Invention

[0003] To address at least one of the aforementioned technical problems, this application provides an automatic clamping and centering mechanism for composite material plate tensile testing. Using this method and mechanism, plate-type test specimens with a width of 10 mm to 38 mm can be clamped and centered, covering the dimensions specified in most plate-type test specimen testing standards.

[0004] The automatic clamping and centering mechanism for tensile testing of composite material plates provided in this application mainly includes:

[0005] The L-shaped base has a first panel and a second panel that are perpendicular to each other. The first panel has two horizontal strip holes that are symmetrical about the central axis and a vertical strip hole located on the central axis. The second panel is provided with a spring connecting rod.

[0006] A linkage mechanism is provided on the side of the first panel facing the second panel. It includes a first connecting rod and a second connecting rod. The first end of the first connecting rod and the first end of the second connecting rod are hinged by a pin. The pin passes through the vertical strip hole and slides within the vertical strip hole. The second end of the first connecting rod is connected to a first slider, and the second end of the second connecting rod is connected to a second slider. The first slider and the second slider pass through two horizontal strip holes on the first panel respectively and form two clamping protrusions on the side of the first panel facing away from the second panel. One of the first sliders and the second slider is connected to a spring connecting rod on the side of the first panel facing the second panel by a tension spring.

[0007] Preferably, the pin is connected to a nut after passing through the vertical slot in the first panel.

[0008] Preferably, the slider connecting the spring connecting rod has an annular protrusion, and a front section and a rear section divided by the annular protrusion. The annular protrusion is pressed between the second end of the first connecting rod or the second connecting rod of the linkage mechanism and the first panel. The front section passes through the transverse strip hole of the first panel, and the rear section passes through the second end of the first connecting rod or the second connecting rod and forms an annular groove along the rear section. One end of the tension spring has a pull ring installed in the annular groove.

[0009] Preferably, one of the first slider and the second slider is configured as a wedge slider, with one end of the wedge slider having an inclined surface passing through the transverse strip hole of the first panel and its inclined surface facing away from the other slider, and the other end of the wedge slider being connected to the second end of the first connecting rod or the second connecting rod of the linkage mechanism via a spring.

[0010] Preferably, the second end of the first or second connecting rod of the linkage mechanism that connects to one of the wedge-shaped sliders has a groove facing the transverse strip hole, and one end of the wedge-shaped slider extends into the groove and is connected to a spring located in the groove.

[0011] Preferably, the second panel of the L-shaped base is provided with a connection hole for connecting to the test piece clamping block.

[0012] The automatic clamping and centering mechanism for composite material plate tensile testing provided in this application can center the test specimen with the test specimen clamping block in the width direction, which solves the problem of difficulty in adjusting the limit bar when conducting tests in high and low temperature environmental chambers, while saving test time and improving test efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of the automatic clamping and centering mechanism for composite material plate tensile testing in this application.

[0014] Figure 2 yesFigure 1 Left view of the embodiment shown.

[0015] Figure 3 yes Figure 2 A cross-sectional view of the embodiment shown.

[0016] Figure 4 yes Figure 1 Top view of the embodiment shown.

[0017] Figure 5 yes Figure 1 Rear view of the embodiment shown.

[0018] Figure 6 This is an example diagram illustrating the application of the automatic clamping and centering mechanism for composite material plate tensile testing in this application.

[0019] Among them, 1-L-shaped base, 11-first panel, 12-second panel, 13-horizontal strip hole, 14-vertical strip hole;

[0020] 2-First connecting rod, 3-Second connecting rod, 4-First slider, 5-Second slider, 6-Spring connecting rod, 7-Tension spring, 8-Spring, 9-Pin, 10-Nut;

[0021] 20 - Test piece clamping block; 30 - Test piece. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0023] This application provides an automatic clamping and centering mechanism for tensile testing of composite material plates, such as... Figures 1 to 5 As shown, it mainly includes:

[0024] The L-shaped base 1 has a first panel 11 and a second panel 12 that are perpendicular to each other. The first panel 11 has two horizontal strip holes 13 that are symmetrical about the central axis and a vertical strip hole 14 located on the central axis. The second panel 12 is provided with a spring connecting rod 6.

[0025] A linkage mechanism is provided on the side of the first panel 11 facing the second panel 12. It includes a first connecting rod 2 and a second connecting rod 3. The first end of the first connecting rod 2 and the first end of the second connecting rod 3 are hinged by a pin 9. The pin 9 passes through the vertical strip hole 14 and slides within the vertical strip hole 14. The second end of the first connecting rod 2 is connected to a first slider 4, and the second end of the second connecting rod 3 is connected to a second slider 5. The first slider 4 and the second slider 5 pass through two horizontal strip holes 13 on the first panel 11 respectively and form two clamping protrusions on the side of the first panel 11 facing away from the second panel 12. One of the first slider 4 and the second slider 5 is connected to a spring connecting rod 6 on the side of the first panel 11 facing the second panel 12 by a tension spring 7.

[0026] refer to Figure 3 Due to the force of the tension spring 7, the first slider 4 and the second slider 5 move closer to each other, that is, they are located at the innermost side of the transverse strip hole 13 and are equidistant from the central axis of the first panel 11. (Refer to...) Figure 4 and Figure 6 The test piece 30 is placed between the first slider 4 and the second slider 5. Based on the force of the tension spring 7, the test piece 30 is positioned precisely in the center of the L-shaped base 1. Due to the linkage mechanism, the first slider 4 and the second slider 5 can only slide the same distance in opposite directions. Therefore, the center of the test piece 30 along its width direction coincides exactly with the centerline of the L-shaped base. (Refer to...) Figure 6 The L-shaped base 1 is fixed in the middle of the test piece clamping block and is located in the exact center of the test piece clamp 20, which ensures that the test piece clamp 20 clamps the test piece clamping block and the test piece.

[0027] In some alternative embodiments, the pin 9 is connected to a nut 10 after passing through the vertical slot 14 of the first panel 11.

[0028] refer to Figure 5In this embodiment, one end of the pin 9 is slidably disposed within the vertical slot 14, and the other end is sleeved with the first connecting rod 2 and the second connecting rod 3. Finally, the nut 10 is installed to press the first ends of the first connecting rod 2 and the second connecting rod 3 against the first panel 11. The pressing force should not be too large to prevent excessive friction from affecting the sliding of the pin 9 within the vertical slot 14. In this embodiment, an annular groove track recessed along the inner wall of the vertical slot 14 can be provided inside the slot 14. The end of the pin 9 that enters the vertical slot 14 is provided with a corresponding annular protrusion, which cooperates with the annular groove track to axially limit the pin 9. In an alternative embodiment, both ends of the pin 9 can be provided with external threads. As described above, on the side of the first panel 11 facing the second panel 12, the first connecting rod 2 and the second connecting rod 3 are first installed, and then the nut 10 is installed. The other end passes through the vertical strip hole 14 and then a nut is also installed on the side of the first panel 11 facing away from the second panel 12. The outer diameter of the nut is larger than the width of the vertical strip hole 14, so that by squeezing from both ends, the first ends of the first connecting rod 2 and the second connecting rod 3 are squeezed to fit against the first panel 11.

[0029] In some alternative implementations, such as Figure 3 As shown, the slider of the connecting spring connecting rod 6 has an annular protrusion, and a front section and a rear section divided by the annular protrusion. The annular protrusion is pressed between the second end of the first connecting rod 2 or the second connecting rod 3 of the linkage mechanism and the first panel 11. The front section passes through the transverse strip hole 13 of the first panel 11, and the rear section passes through the second end of the first connecting rod 2 or the second connecting rod 3 and forms an annular groove along the rear section. One end of the tension spring 7 has a pull ring installed in the annular groove.

[0030] In some alternative embodiments, one of the first slider 4 and the second slider 5 is configured as a wedge slider. One end of the wedge slider with an inclined surface passes through the transverse strip hole 13 of the first panel 11, and its inclined surface faces away from the other slider. The other end of the wedge slider is connected to the second end of the first connecting rod 2 or the second connecting rod 3 of the linkage mechanism by a spring 8.

[0031] refer to Figure 3 In this embodiment, taking the second slider 5 as an example, the second slider 5 is a wedge-shaped slider with its inclined surface facing away from the first slider 4. The test piece slides from the side of the first panel 11 closest to the second slider 5 towards the center of the first panel 11, first contacting the second slider 5. The side of the test piece abuts against the inclined surface of the second slider 5, compressing the spring 8 of the second slider 5, causing a portion of the second slider 5 to enter the second connecting rod 3. The test piece continues to be pushed in, causing it to contact the first slider 4 and push the first slider 4 to move to the other side of the first panel 11. The first slider 4 pulls the tension spring 7. At this time, based on the first connecting rod 2, referencing... Figure 1Pin 9 moves downward in the vertical slot 14. Similarly, based on the second connecting rod 3, it drives the second slider 5 to slide towards the test piece, thereby increasing the clamping space between the first slider 4 and the second slider 5 until the test piece surface no longer presses the second slider 5. At this time, the second slider 5 pops out under the push of the spring 8. After the second slider 5 pops out, it releases the test piece. Under the pull of the tension spring 7, the test piece is just stuck in the middle position of the L-shaped base.

[0032] It should be noted that both the first slider 4 and the second slider 5 can be configured as wedge-shaped sliders, with the inclined surfaces of the two wedge-shaped sliders facing away from each other. When both sliders are wedge-shaped sliders, the end of the tension spring 7 can be directly connected to the second end of the first connecting rod 2 or the second connecting rod 3, instead of using... Figure 3 The connection method shown in the embodiment is connected to the rear section of the first slider 4.

[0033] In some alternative embodiments, the second end of the first connecting rod 2 or the second connecting rod 3 of the linkage mechanism that connects to one of the wedge sliders has a groove facing the transverse strip hole 13, and one end of the wedge slider extends into the groove and is connected to the spring 8 located in the groove.

[0034] This embodiment uses grooves to prevent the wedge slider from shifting during axial movement.

[0035] In some alternative embodiments, the second panel 12 of the L-shaped base 1 is provided with a connection hole for connecting to the test piece clamping block.

[0036] In this embodiment, the L-shaped base is mounted on the test specimen clamping block using screws through two holes on the L-shaped base. The corresponding test specimen clamping block has pre-drilled threaded holes. In an alternative embodiment, other connection methods such as snap-fit ​​can also be used to connect the L-shaped base 1 to the test specimen clamping block.

[0037] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An automatic clamping and centering mechanism for tensile testing of composite material plates, characterized in that, include: L-shaped base (1) has a first panel (11) and a second panel (12) that are perpendicular to each other. The first panel (11) has two horizontal strip holes (13) that are symmetrical about the central axis and a vertical strip hole (14) located on the central axis. The second panel (12) is provided with a spring connecting rod (6). A linkage mechanism is provided on the side of the first panel (11) facing the second panel (12). It includes a first connecting rod (2) and a second connecting rod (3). The first end of the first connecting rod (2) and the first end of the second connecting rod (3) are hinged by a pin (9). The pin (9) passes through the vertical strip hole (14) and slides in the vertical strip hole (14). The second end of the first connecting rod (2) is connected to a first slider (4). The second end of the second connecting rod (3) is connected to a second slider (5). The first slider (4) and the second slider (5) pass through two horizontal strip holes (13) on the first panel (11) respectively and form two clamping protrusions on the side of the first panel (11) facing away from the second panel (12). One of the first sliders (4) and the second slider (5) is connected to a spring connecting rod (6) by a tension spring (7) on the side of the first panel (11) facing the second panel (12). The slider of the connecting spring connecting rod (6) has an annular protrusion, and a front section and a rear section divided by the annular protrusion. The annular protrusion is pressed between the second end of the first connecting rod (2) or the second connecting rod (3) of the linkage mechanism and the first panel (11). The front section passes through the transverse strip hole (13) of the first panel (11). After the rear section passes through the second end of the first connecting rod (2) or the second connecting rod (3), an annular groove is formed along the rear section. One end of the tension spring (7) has a pull ring installed in the annular groove. One of the first slider (4) and the second slider (5) is configured as a wedge slider. After the inclined end of the wedge slider passes through the transverse strip hole (13) of the first panel (11), its inclined end faces away from the other slider. The other end of the wedge slider is connected to the second end of the first connecting rod (2) or the second connecting rod (3) of the linkage mechanism by a spring (8).

2. The automatic clamping and centering mechanism for composite material plate tensile testing as described in claim 1, characterized in that, The pin (9) is connected to a nut (10) after passing through the vertical slot (14) of the first panel (11).

3. The automatic clamping and centering mechanism for composite material plate tensile testing as described in claim 1, characterized in that, The second end of the first connecting rod (2) or the second connecting rod (3) of the linkage mechanism that connects to one of the wedge sliders has a groove facing the transverse strip hole (13), one end of the wedge slider extends into the groove and is connected to the spring (8) located in the groove.

4. The automatic clamping and centering mechanism for composite material plate tensile testing as described in claim 1, characterized in that, The second panel (12) of the L-shaped base (1) is provided with a connection hole for connecting with the test piece clamping block.

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