Composite material in-plane shear performance testing device capable of improving measurement precision

Abstract

The utility model discloses a composite material in-plane shear performance testing device capable of improving measurement accuracy, which comprises a first L-shaped fixing groove, a second L-shaped fixing groove, a clamping block, a clamp bolt and a composite material sample, the outer walls of the opposite sides of the first L-shaped fixing groove and the second L-shaped fixing groove are provided with fixing ports, the clamping block is positioned in the fixing ports, and the clamp bolt is positioned in the clamping block. The composite material sample is located in the middle of the clamping block, the first L-shaped fixing groove and the second L-shaped fixing groove are inserted into pressing positioning holes in the surface of the clamping block through clamp bolts to fix the clamping block, and mounting grooves are formed in the bottom of the first L-shaped fixing groove and the top of the second L-shaped fixing groove; a sample pressing mechanism is mounted in the mounting groove; according to the utility model, the sample can be tightly pressed in the fixing groove and locked, so that a gap between the sample and the fixing groove is eliminated; in the testing process, deflection and inclination caused by the gap are avoided, and therefore the testing precision is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a shearing performance testing device, especially to a composite material in-plane shearing performance testing device capable of improving measurement accuracy. BACKGROUND

[0002] Composite material is a new material formed by optimizing and combining materials with different properties by using advanced material preparation technology. In the production process of composite material, in order to ensure the production quality of the material, the shearing performance of the material needs to be tested, which requires a shearing performance testing device.

[0003] In the prior art, referring to Figure 5 , the shearing performance testing device generally comprises a testing machine interface, two L-shaped fixing grooves, clamp bolts (used for locking the sample clamping block), two sample centering pads, pad screws, strain gauges and a composite material sample. The composite material sample is located between the two L-shaped fixing grooves. The testing machine is used to apply a shearing force to the sample by pulling, thereby achieving the function of testing the in-plane shearing performance.

[0004] However, the above-mentioned shearing performance testing device has the following problems. During the shearing test, the sample deflects and tilts counterclockwise, which causes the shearing process to change into "shearing + tearing", and the test accuracy cannot be guaranteed. In actual testing, the sample inevitably has machining errors. The testing device also reserves a space allowance for installing the sample. The clamping of the fixed block during the test cannot completely fix the sample, especially when the sample is hard and the force value is large. The above factors are superimposed, and the sample will deflect and tilt during the test. Once the deflection and tilting occur, the force applied to the sample is the sum of the shearing force and the tearing force, and the ratio of the two depends on the degree of sample misalignment. On the other hand, as the degree of deformation of the sample increases during the test, the above-mentioned situation will be aggravated. This results in a large error or even a mistake in the shearing test, and therefore there is room for improvement. SUMMARY

[0005] The utility model overcomes the defects of the prior art and provides a composite material in-plane shearing performance testing device capable of improving measurement accuracy.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a composite material in-plane shear performance testing device that can improve measurement accuracy, comprising: a first L-shaped fixing groove, a second L-shaped fixing groove, a clamping block, a clamping bolt, and a composite material sample. The first L-shaped fixing groove and the second L-shaped fixing groove each have a fixing opening on their opposite outer walls. The clamping block is located within the fixing opening, and the composite material sample is located in the middle of the clamping block. Both the first L-shaped fixing groove and the second L-shaped fixing groove are fixed by inserting the clamping bolt into the clamping positioning hole on the surface of the clamping block. The bottom of the first L-shaped fixing groove and the top of the second L-shaped fixing groove each have an installation groove, and a sample clamping mechanism is installed inside the installation groove.

[0007] The sample clamping mechanism includes a connecting cover plate, which is connected to the bottom of the first L-shaped fixing groove and the second L-shaped fixing groove respectively by fixing bolts. A top rod is threadedly connected to the middle of the connecting cover plate. A cylindrical guide block is sleeved on the outside of the top rod. A pressure block is provided at the end of the cylindrical guide block away from the top rod. The pressure block is in contact with the composite material sample. Spring guide rods are provided on the outer walls of the cylindrical guide block on both sides of the pressure block. Springs are sleeved on the outer walls of the spring guide rods.

[0008] In a preferred embodiment of this invention, a rotating cap is provided at the end of the push rod away from the cylindrical guide block, and the rotating cap has a cylindrical structure. The rotating cap allows for easy gripping and rotation of the push rod, improving operational convenience.

[0009] In a preferred embodiment of this invention, both the bottom of the first L-shaped fixing groove and the top of the second L-shaped fixing groove are provided with testing machine interfaces. The provision of testing machine interfaces facilitates connection of the device to a testing machine, improving operational convenience.

[0010] In a preferred embodiment of this invention, centering assemblies are provided at both the top and bottom of the composite material specimen, and these assemblies can be inserted into the interior of the composite material specimen. The centering assemblies ensure that the specimen is centered vertically, horizontally, and front-back, ensuring that the shear force applied during the test is located within the working area of ​​the specimen, thereby guaranteeing test accuracy.

[0011] In a preferred embodiment of the present invention, the centering assembly includes two baffles, and the two baffles are connected to the same centering block by a spacer bolt.

[0012] In a preferred embodiment of this invention, both the first L-shaped fixing groove and the second L-shaped fixing groove are provided with a track shaft. The track shaft of the first L-shaped fixing groove can be inserted into the graphite copper sleeve of the second L-shaped fixing groove, and the track shaft of the second L-shaped fixing groove can be inserted into the graphite copper sleeve of the first L-shaped fixing groove. The track shaft and the graphite copper sleeve constitute a motion track, ensuring that the motion trajectory of the L-shaped fixing groove is parallel to the working area during testing, thereby improving testing accuracy.

[0013] In a preferred embodiment of this invention, a positioning groove is provided on the outer wall of the second L-shaped fixing groove, and a limit stop is inserted into the positioning groove. When loading the sample, the limit stop is pulled out to allow the sample to pass through; during testing, the limit stop is inserted to limit the deflection of the sample.

[0014] In a preferred embodiment of this invention, both the upper and lower ends of the clamping block are double-sided beveled edges. This design, with double-sided beveled edges at both ends, allows for sufficient working space for the sample clamping mechanism and prevents contact with it.

[0015] This utility model solves the defects existing in the background technology, and has the following beneficial effects:

[0016] (1) The test apparatus is designed with a sample clamping mechanism in the vertical direction of the L-shaped fixed groove, which can press the sample tightly into the fixed groove and lock it, eliminating the gap between the sample and the fixed groove; during the test, the deflection and tilt caused by the gap are avoided, thereby improving the test accuracy.

[0017] (2) The improved testing device features an added motion guide rail design in the "L-shaped fixed groove" structure. This design constrains the relative motion of the "L-shaped fixed groove" to a track parallel to the shear force, achieving true in-plane shearing. This design offers several advantages: it reduces the deflection and tilt caused by the strain of the sample, thereby improving measurement accuracy; it avoids damage to the sensor and connecting mechanism caused by the force deflection of the "L-shaped fixed groove"; and it avoids measurement errors caused by the force deflection of the "L-shaped fixed groove".

[0018] (3) The test device has a pluggable limit block at the bottom of the "L-shaped fixing groove" on the right side, so that when loading the sample, it is not necessary to remove the entire test device from the test machine each time, combine it with the sample, and then connect the combined body to the test machine. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0020] Figure 1 This is a perspective structural diagram of a preferred embodiment of the present invention;

[0021] Figure 2 This is an internal structural diagram of a preferred embodiment of the present invention;

[0022] Figure 3 This is a structural diagram of the sample clamping mechanism of a preferred embodiment of the present invention;

[0023] Figure 4 This is a structural diagram of the centering assembly according to a preferred embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of an existing shear performance testing device.

[0025] In the figure: 1. First L-shaped fixing groove; 2. Clamp bolt; 3. Second L-shaped fixing groove; 4. Graphite copper sleeve; 5. Track shaft; 6. Testing machine interface; 7. Sample clamping mechanism; 71. Fixing bolt; 72. Rotating cap; 73. Connecting cover plate; 74. Pressure block; 75. Spring; 76. Cylindrical guide block; 77. Top rod; 8. Centering assembly; 81. Centering block; 82. Baffle; 83. Pad bolt; 9. Clamping block; 10. Limiting block; 11. Composite material sample. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0027] like Figures 1-4 As shown, a composite material in-plane shear performance testing device that can improve measurement accuracy includes: a first L-shaped fixing groove 1, a second L-shaped fixing groove 3, a clamping block 9, a clamping bolt 2, and a composite material sample 11. The outer walls of the first L-shaped fixing groove 1 and the second L-shaped fixing groove 3 on opposite sides are provided with fixing openings. The clamping block 9 is located inside the fixing openings, and the composite material sample 11 is located in the middle of the clamping block 9. The first L-shaped fixing groove 1 and the second L-shaped fixing groove 3 are both fixed by inserting the clamping bolt 2 into the pressing and positioning hole on the surface of the clamping block 9. The bottom of the first L-shaped fixing groove 1 and the top of the second L-shaped fixing groove 3 are provided with mounting grooves, and a sample clamping mechanism 7 is installed inside the mounting grooves.

[0028] The sample clamping mechanism 7 includes a connecting cover plate 73, which is connected to the bottom of the first L-shaped fixing groove 1 and the second L-shaped fixing groove 3 respectively by fixing bolts 71. A top rod 77 is threadedly connected to the middle of the connecting cover plate 73. A cylindrical guide block 76 is sleeved on the outside of the top rod 77. A pressure block 74 is provided at the end of the cylindrical guide block 76 away from the top rod 77. The pressure block 74 is in contact with the composite material sample 11. Spring guide rods are provided on the outer walls of both sides of the cylindrical guide block 76 and pressure block 74. Springs 75 are sleeved on the outer walls of the spring guide rods.

[0029] A rotating cap 72 is provided at the end of the push rod 77 away from the cylindrical guide block 76. The rotating cap 72 has a cylindrical structure. The rotating cap 72 makes it easy to pinch the rotating cap 72 to rotate the push rod 77, improving the convenience of operation.

[0030] The bottom of the first L-shaped fixing groove 1 and the top of the second L-shaped fixing groove 3 are both provided with testing machine interfaces 6. The provision of testing machine interfaces 6 facilitates the connection of the device to the testing machine, improving the ease of operation.

[0031] The composite material specimen 11 is provided with centering assemblies 8 at both the top and bottom, which can be inserted into the interior of the composite material specimen 11. The centering assemblies 8 are provided to ensure that the specimen is centered in all directions (up, down, left, right, front, and back), and to ensure that the shear force applied during the test is located in the working area of ​​the specimen, so as to ensure the accuracy of the test. The centering assemblies 8 include two baffles 82, which are connected to the same centering block 81 by spacer bolts 83.

[0032] Both the first L-shaped fixing groove 1 and the second L-shaped fixing groove 3 are equipped with track shafts 5. The track shaft 5 of the first L-shaped fixing groove 1 can be inserted into the graphite copper sleeve 4 of the second L-shaped fixing groove 3, and the track shaft of the second L-shaped fixing groove 3 can be inserted into the graphite copper sleeve 4 of the first L-shaped fixing groove 1. The track shaft 5 and the graphite copper sleeve 4 form a motion track, ensuring that the motion trajectory of the L-shaped fixing groove is parallel to the working area during testing, thus improving the testing accuracy.

[0033] The outer wall of the second L-shaped fixing groove 3 is provided with a positioning groove, and a limit stop 10 is inserted into the positioning groove. When loading the sample, the limit stop 10 is pulled out to allow the sample to pass through; during testing, the limit stop 10 is inserted to limit the deflection of the sample.

[0034] The upper and lower ends of the clamping block 9 are both beveled. The design of the upper and lower ends of the clamping block 9 being beveled on both sides can make it easier to leave working space for the sample clamping mechanism 7 and prevent it from touching the sample clamping mechanism 7.

[0035] In use, rotating the top rod 77 clockwise drives the combination of the cylindrical guide block 76 and the pressure block 74 to press the sample downwards. The top rod 77 is designed with a locking thread to prevent slippage and loosening during testing. Rotating the top rod 77 counterclockwise lifts the combination of the cylindrical guide block 76 and the pressure block 74 by the spring 75, releasing the sample. The cylindrical guide block 76 ensures that the pressure block 74 assembly moves only vertically up and down. The spring guide rod serves as a guide for the spring 75 and also ensures that the cylindrical guide block 76 prevents the pressure block 74 assembly from rotating. This tightly presses the sample into the fixed groove and locks it in place, eliminating the gap between the sample and the fixed groove. During testing, this avoids deflection and tilting caused by the gap, thereby improving testing accuracy.

[0036] Based on the preferred embodiments of this utility model described above, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A device for testing the in-plane shear properties of composite materials that can improve measurement accuracy, comprising: The first L-shaped fixing groove (1), the second L-shaped fixing groove (3), the clamping block (9), the clamping bolt (2) and the composite material sample (11) are provided. The first L-shaped fixing groove (1) and the second L-shaped fixing groove (3) are provided with fixing openings on opposite outer walls. The clamping block (9) is located inside the fixing opening. The composite material sample (11) is located in the middle of the clamping block (9). The first L-shaped fixing groove (1) and the second L-shaped fixing groove (3) are both fixed by inserting the clamping bolt (2) into the pressing positioning hole on the surface of the clamping block (9). The first L-shaped fixing groove (1) and the second L-shaped fixing groove (3) are provided with mounting grooves. The sample pressing mechanism (7) is installed inside the mounting groove. The sample clamping mechanism (7) includes a connecting cover plate (73), which is connected to the bottom of the first L-shaped fixing groove (1) and the second L-shaped fixing groove (3) respectively by fixing bolts (71). A top rod (77) is threadedly connected to the middle part of the connecting cover plate (73). A cylindrical guide block (76) is sleeved on the outside of the top rod (77). A pressure block (74) is provided at the end of the cylindrical guide block (76) away from the top rod (77). The pressure block (74) is in contact with the composite material sample (11). Spring guide rods are provided on the outer walls of the cylindrical guide block (76) on both sides of the pressure block (74). Springs (75) are sleeved on the outer walls of the spring guide rods.

2. The composite material in-plane shear performance testing device according to claim 1, which can improve measurement accuracy, is characterized in that: The top rod (77) is provided with a rotating cap (72) at the end away from the cylindrical guide block (76), and the rotating cap (72) has a cylindrical structure.

3. The composite material in-plane shear performance testing device according to claim 1, characterized in that: The bottom of the first L-shaped fixing groove (1) and the top of the second L-shaped fixing groove (3) are both provided with testing machine interfaces (6).

4. The composite material in-plane shear performance testing device according to claim 1, characterized in that: The top and bottom of the composite material specimen (11) are provided with centering assemblies (8), which can be inserted into the interior of the composite material specimen (11).

5. The composite material in-plane shear performance testing device according to claim 4, characterized in that: The centering assembly (8) includes two baffles (82), which are connected to the same centering block (81) by pad bolts (83).

6. The composite material in-plane shear performance testing device according to claim 1, characterized in that: Both the first L-shaped fixing groove (1) and the second L-shaped fixing groove (3) are provided with a track shaft (5). The track shaft (5) of the first L-shaped fixing groove (1) can be inserted into the graphite copper sleeve (4) of the second L-shaped fixing groove (3), and the track shaft of the second L-shaped fixing groove (3) can be inserted into the graphite copper sleeve (4) of the first L-shaped fixing groove (1).

7. The composite material in-plane shear performance testing device according to claim 1, characterized in that: The outer wall of the second L-shaped fixing groove (3) is provided with a positioning groove, and a limit stop (10) is inserted into the positioning groove.

8. A composite material in-plane shear performance testing device according to any one of claims 1-7, characterized in that: The upper and lower ends of the clamping block (9) are both beveled.

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