Compact tensile sample clamp for testing fracture toughness

Abstract

The utility model provides a compact tensile sample fixture for fracture toughness test, which comprises an upper chuck and a lower chuck, the upper chuck and the lower chuck are both vertically placed and opposite in position, and the upper end of the upper chuck and the lower end of the lower chuck are both provided with hydraulic servo testing machine fixing parts. The hydraulic servo testing machine fixing part refers to a chuck joint of the hydraulic servo testing machine and comprises a plurality of pins, a compact tensile sample groove with a downward opening is formed in the lower end of the upper chuck, a magnet is arranged on the side wall of one side of the compact tensile sample groove of the upper chuck, and an upper pin through hole is formed in the side wall of the other side of the compact tensile sample groove of the upper chuck; an upper pin through hole is formed in the upper end of the lower chuck, a pin can be inserted and fixed in the upper pin through hole, a compact tensile sample groove with an upward opening is formed in the upper end of the lower chuck, a lower pin through hole is formed in the side wall of one side of the compact tensile sample groove of the lower chuck, and the pin can be inserted and fixed in the lower pin through hole. The clamp can reduce the displacement of the compact tensile sample in the fracture toughness test.

Description

TECHNICAL FIELD

[0001] The utility model relates to material mechanics test technical field especially involves compact tension specimen clamp for fracture toughness test. BACKGROUND

[0002] In the field of material engineering, the test of fracture toughness is a key evaluation, which measures the ability of a material to resist crack propagation when subjected to external forces. This test is crucial for ensuring the safety and reliability of structural components during actual operation. It is necessary to accurately evaluate the fracture toughness of the materials used in various industrial applications, from aviation to construction, from automobile manufacturing to energy facilities.

[0003] In conventional fracture toughness testing, hydraulic servo testing machines are the preferred equipment for performing such tests due to their excellent load accuracy and adjustability. Hydraulic servo testing machines are usually connected with a chuck for clamping the specimen during the test. A clamp suitable for composite material I type interlaminar fracture toughness test is disclosed in publication CN209927599U, which includes an upper clamp and a lower clamp. Both the upper clamp and the lower clamp include a connecting device and a clamping block. The connecting device and the clamping block are connected through a universal joint, and the connecting device and the universal joint are connected through a bearing. The connecting device is connected with the hydraulic servo testing machine, and the connecting device is in the shape of a cylinder, directly connecting the chuck of the hydraulic servo testing machine. When performing fracture toughness test, the connecting device is first clamped with the testing machine chuck, then the universal joints on the outer sides of the bearings of the upper and lower clamps are rotated to adjust the horizontal position of the clamping blocks, and the clamping blocks are adjusted to the appropriate position. The pin is inserted into the clamping block (at the chuck of the clamping block) of the upper clamp to fix the test piece. Then, the spatial position of the clamping blocks (in two directions perpendicular to the horizontal plane) is adjusted through the universal joints of the upper and lower clamps to facilitate the centering of the test piece and the clamp. After all adjustments are completed, the positioning pin is inserted into the clamping block of the lower clamp, and the test can begin. However, in actual fracture toughness testing, the specimen may displace during deformation, leading to asymmetric crack boundaries. This problem is particularly pronounced in the study of compact tension specimens, which have a small size and a special structure. The displacement caused by deformation during the experiment has a significant impact on the test results, especially in fracture toughness testing, where poor centering accuracy can easily lead to asymmetric crack boundaries and invalid test results. Therefore, how to reduce the displacement of compact tension specimens during fracture toughness testing has become a difficult problem. SUMMARY

[0004] The technical problem to be solved by the utility model is to provide a compact tension specimen clamp for fracture toughness test, which can reduce the displacement of compact tension specimens during fracture toughness testing.

[0005] The technical solution adopted by the utility model to solve its technical problem is:

[0006] The compact tension specimen clamp for fracture toughness test comprises a plurality of pins, an upper clamp head and a lower clamp head, the upper clamp head and the lower clamp head are vertically arranged and oppositely positioned, the upper end of the upper clamp head and the lower end of the lower clamp head are respectively provided with a hydraulic servo testing machine fixing part, the lower end of the upper clamp head and the upper end of the lower clamp head are respectively provided with a compact tension specimen groove, the side wall of the compact tension specimen groove of the upper clamp head and the side wall of the compact tension specimen groove of the lower clamp head are respectively provided with a pin through hole, the pin can be inserted and fixed in the pin through hole, the side wall of the compact tension specimen groove of the upper clamp head, which is away from the pin through hole, is provided with a magnet, the outer side wall of the compact tension specimen groove of the upper clamp head is engraved with an alignment mark, the side wall of the compact tension specimen groove of the lower clamp head, which is away from the pin through hole, is provided with a magnet, and the corresponding position of the side wall of the compact tension specimen groove of the lower clamp head is engraved with an alignment mark.

[0007] Further, the compact tension specimen groove of the upper clamp head and the compact tension specimen groove of the lower clamp head are two grooves with the same opening size and coaxial center axes.

[0008] Further, the side wall of the compact tension specimen groove of the upper clamp head is engraved with an alignment mark, and the corresponding position of the side wall of the compact tension specimen groove of the lower clamp head is also engraved with an alignment mark.

[0009] Further, the upper pin through hole and the lower pin through hole are in position correspondence and have the same hole diameter.

[0010] Further, the plurality of pins are cylindrical pins, when the pin is inserted into the upper pin through hole, the pin is in interference fit with the upper pin through hole, and when the pin is inserted into the lower pin through hole, the pin is in interference fit with the lower pin through hole.

[0011] The compact tension specimen clamp for fracture toughness test has the advantages that:

[0012] The compact tension specimen clamp for fracture toughness test has the advantages that:

[0013] The upper clamp has a compact tensile specimen groove with an opening downward at the lower end, and an upper pin hole is arranged on the side wall of the compact tensile specimen groove of the upper clamp, and the pin can be inserted and fixed in the upper pin hole; the lower clamp has a compact tensile specimen groove with an opening upward at the upper end, and a lower pin hole is arranged on the side wall of the compact tensile specimen groove of the lower clamp, and the pin can be inserted and fixed in the lower pin hole. The simple clamping mode can significantly reduce the specimen device time. Assuming that 30 minutes are required for each device originally, the compact tensile specimen clamp can reduce the time to 10 minutes, and 20 minutes are saved each time. In a high-frequency test environment, such time saving can greatly improve the overall test throughput, and a magnet is arranged on the side wall of the compact tensile specimen groove of the upper clamp away from the pin hole, alignment marks are engraved on the outer side wall of the compact tensile specimen groove of the upper clamp, a magnet is arranged on the side wall of the compact tensile specimen groove of the lower clamp away from the pin hole, and alignment marks are engraved on the corresponding positions of the side of the compact tensile specimen groove of the lower clamp. The design of the magnet and the alignment marks can reduce the displacement of the compact tensile specimen in the fracture toughness test.

[0014] The compact tensile specimen grooves of the upper clamp and the lower clamp have the same opening size and coaxial center axes, so that the specimen can always be centered during the test, the eccentric load phenomenon is avoided, and the accuracy and reliability of the test result are improved.

[0015] The compact tensile specimen grooves of the upper clamp and the lower clamp are engraved with alignment marks on the side, so that the operator can quickly align when installing the specimen, the operation steps are simplified, and human errors are reduced. Through the accurate alignment marks and reliable pin fixation, the specimen can be kept stable during the test, the test error caused by the displacement or eccentric load of the specimen is reduced, and the precision and repeatability of the test result are improved.

[0016] The upper pin hole and the lower pin hole are in corresponding positions and have the same hole diameter, so that the pin can be inserted and fixed in the two holes at the same time, the fixing effect of the specimen is enhanced, and the displacement of the specimen during the test is prevented.

[0017] The pin and the hole are in interference fit, which further improves the reliability and stability of the fixation, so that the specimen will not be loose under high stress conditions, thereby ensuring the accuracy of the test data.

[0018] The interference fit pin design ensures the stability of the specimen under high stress conditions, and avoids test failure or data distortion caused by poor fixation. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application, the drawings required in the embodiments will be briefly introduced as follows.

[0020] Figure 1 is a structure sectional view of the compact tensile specimen clamp for fracture toughness test.

[0021] Figure 2 is a schematic view of the structure of a compact tension specimen clamp for fracture toughness testing.

[0022] Figure 3 is a schematic view of the structure of a pin.

[0023] In the figure, 1 is an upper clamp head, 2 is a lower clamp head, and 3 is a pin. DETAILED DESCRIPTION

[0024] The utility model is further described below in combination with the drawings.

[0025] In order to make the purpose, technical scheme and advantages of the utility model more clear and obvious, the utility model is further described in detail below in combination with the drawings and examples, and it should be understood that the specific examples described below are only used to explain the utility model and do not limit the utility model.

[0026] In the description in the utility model, it should be understood that the orientation or position relationship indicated by the terms such as 'upper', 'lower', 'inner' and 'outer' should be understood in a broad sense, and is not used to limit the protection scope of the utility model, and for ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0027] The compact tension specimen clamp for fracture toughness testing comprises a plurality of pins 3, an upper clamp head 1 and a lower clamp head 2, the upper clamp head 1 and the lower clamp head 2 are both vertically placed and oppositely positioned, the upper end of the upper clamp head 1 and the lower end of the lower clamp head 2 are both provided with a hydraulic servo testing machine fixing part, the lower end of the upper clamp head 1 and the upper end of the lower clamp head 2 are both provided with a compact tension specimen groove, the side wall of the compact tension specimen groove of the upper clamp head 1 and the side wall of the compact tension specimen groove of the lower clamp head 2 are both provided with a pin through hole, the pin 3 can be inserted and fixed in the pin through hole, and the compact tension specimen groove of the upper clamp head 1 is characterized in that the side wall of the side of the compact tension specimen groove away from the pin through hole is provided with a magnet, the outer side wall of the compact tension specimen groove of the upper clamp head 1 is engraved with an alignment mark, the side wall of the side of the compact tension specimen groove of the lower clamp head 2 away from the pin through hole is provided with a magnet, and the corresponding position of the side of the compact tension specimen groove of the lower clamp head 2 is engraved with an alignment mark.

[0028] As Figure 1As shown, in actual use, the upper clamp head 1 and the lower clamp head 2 are carefully checked to adapt to the size and shape of the compact tension specimen, and it is ensured that the clamp can firmly fix the specimen. The compact tension specimen is placed between the upper clamp head 1 and the lower clamp head 2, and the specimen is tightly adsorbed by the magnet to ensure that the specimen is in the correct position. Through the upper pin through hole and the lower pin through hole, the specimen is fixed by using a plurality of pins 3. It is ensured that the pins 3 are firmly installed to prevent the specimen from moving or falling off during the test. The upper end of the upper clamp head 1 and the lower end of the lower clamp head 2 are respectively fixed on the hydraulic servo testing machine through the hydraulic clamp of the hydraulic servo testing machine, and it is ensured that the clamp and the specimen are fixed stably. The fixing state of the hydraulic clamp is confirmed to avoid loosening of the clamp or displacement of the specimen during the test. Start the hydraulic servo testing machine and perform the fracture toughness test according to the preset load condition. Monitor the data changes during the test to ensure the accuracy and reliability of the test results. After the test is completed, turn off the hydraulic servo testing machine and remove the clamp and the specimen. Clean and maintain the clamp to ensure its good condition for next use.

[0029] As shown in Figure 1 The compact tension specimen groove of the upper clamp head and the compact tension specimen groove of the lower clamp head are two grooves with the same opening size and coaxial center axes.

[0030] The compact tension specimen grooves of the upper clamp head 1 and the lower clamp head 2 have the same opening size and coaxial center axes, which ensures that the specimen always remains centered during the test, avoids the phenomenon of eccentric load, and improves the accuracy and reliability of the test results.

[0031] Further, the positions of the magnets on the side walls of the compact tension specimen grooves of the upper clamp head 1 and the lower clamp head 2 correspond to each other.

[0032] The magnet positions of the compact tension specimen grooves of the upper clamp head 1 and the lower clamp head 2 correspond to each other, which facilitates the operator to quickly align when installing the specimen, simplifies the operation steps, and reduces human error. It ensures that the specimen remains stable during the test, reduces the test error caused by specimen displacement or eccentric load, and improves the precision and repeatability of the test results.

[0033] Further, the upper pin through hole and the lower pin through hole are in corresponding positions and have the same hole diameter.

[0034] The upper pin through hole and the lower pin through hole are in corresponding positions and have the same hole diameter, which ensures that the pins can be inserted and fixed in the two through holes at the same time, enhances the fixing effect of the specimen, and prevents the specimen from displacing during the test.

[0035] Further, the plurality of pins 3 are cylindrical pins, and when the pins 3 are inserted into the upper pin through hole, the pins 3 are in interference fit with the upper pin through hole, and when the pins 3 are inserted into the lower pin through hole, the pins 3 are in interference fit with the lower pin through hole.

[0036] The pin 3 is in interference fit with the through hole, further improving the reliability and stability of the fixation, ensuring that the sample will not loosen under high stress conditions, thereby ensuring the accuracy of the test data.

[0037] The interference fit pin 3 design ensures the stability of the sample under high stress conditions, avoiding test failure or data distortion due to poor fixation.

[0038] The compact tensile specimen clamp for fracture toughness testing provided by the utility model is not limited in preparation process and surface treatment method, and various modifications and changes can be made for the technical personnel in the field. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A compact tensile specimen fixture for fracture toughness testing, comprising a plurality of pins (3), an upper chuck (1) and a lower chuck (2), wherein the upper chuck (1) and the lower chuck (2) are both vertically placed and positioned relative to each other, the upper end of the upper chuck (1) and the lower end of the lower chuck (2) are both provided with a hydraulic servo test machine fixing portion, the lower end of the upper chuck (1) and the upper end of the lower chuck (2) are both provided with a compact tensile specimen groove, the side walls of the compact tensile specimen groove of the upper chuck (1) and the side walls of the compact tensile specimen groove of the lower chuck (2) are both provided with pin through holes, the pins (3) can be inserted into and fixed in the pin through holes, and the invention is characterized in that: A magnet is provided on the side wall of the compact tensile sample slot of the upper chuck (1) away from the pin through hole, and an alignment mark is engraved on the outer side wall of the compact tensile sample slot of the upper chuck (1); a magnet is provided on the side wall of the compact tensile sample slot of the lower chuck (2) away from the pin through hole, and an alignment mark is engraved on the corresponding position of the side surface of the compact tensile sample slot of the lower chuck (2).

2. The compact tensile specimen fixture for fracture toughness testing according to claim 1, characterized in that: The compact tensile specimen slot of the upper chuck (1) and the compact tensile specimen slot of the lower chuck (2) are two slots with the same opening size and coaxial central axes.

3. The compact tensile specimen fixture for fracture toughness testing according to claim 2, characterized in that: The position of the magnet on the side wall of the compact tensile sample slot of the upper chuck (1) corresponds to the position of the magnet on the side wall of the compact tensile sample slot of the lower chuck (2).

4. The compact tensile specimen fixture for fracture toughness testing according to claim 1, characterized in that: The upper pin through hole and the lower pin through hole correspond in position and have the same hole diameter.

5. The compact tensile specimen fixture for fracture toughness testing according to claim 1, characterized in that: The plurality of pins (3) are all cylindrical pins. When the pins (3) are inserted into the upper pin through holes, the pins (3) are interference fit with the upper pin through holes. When the pins (3) are inserted into the lower pin through holes, the pins (3) are interference fit with the lower pin through holes.

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