A clamp for axial tensile testing of concrete specimens

Abstract

This utility model relates to the field of building material testing technology, and discloses a clamp for axial tensile testing of concrete specimens. It includes an upper clamping part and a lower clamping part. The upper clamping part includes a first clamping block and a second clamping block, which are detachably connected. The upper part of the specimen is clamped between the first and second clamping blocks. The lower clamping part includes a third clamping block and a fourth clamping block, which are detachably connected. The lower part of the specimen is clamped between the third and fourth clamping blocks. This utility model, through its separate, detachable structure of the upper and lower clamping parts, changes the traditional bolt point contact clamping to surface contact clamping, effectively eliminating local stress concentration and damage to the specimen, while ensuring accurate LVDT displacement monitoring data, significantly improving the reliability and accuracy of axial tensile testing of high-ductility concrete.

Description

Technical Field

[0001] This utility model relates to the field of building material testing technology, specifically to a fixture for axial tensile testing of concrete specimens. Background Technology

[0002] As a new type of building material, high-ductility concrete requires axial tensile testing as an important experimental method to study its mechanical properties. During the test, the specimen needs to be fixed with clamps, and a linear variable differential transformer (LVDT) is used to monitor the displacement changes in real time during the tensile process.

[0003] Existing clamps such as Figure 1 As shown, the device includes an upper clamping block 17 and a lower clamping block 18, which are used to clamp the upper and lower parts of the test block 3, respectively. Both the upper clamping block 17 and the lower clamping block 18 have through holes 19 on their upper sides for the test block 3 to pass through. Bolts 20 are threaded onto both their front and rear sides, and the test block 3 is held in place by the bolts 20 for testing. However, this technical solution has significant shortcomings: firstly, the method of using bolts 20 to hold the test block 3 can cause localized stress concentration in the test block 3, potentially leading to damage; secondly, during the test, the test block 3 may crack prematurely at the clamping point due to stress concentration, causing the fixture to slip and resulting in significant deviations in the data collected by the LVDT, ultimately affecting the accuracy of the test results. Utility Model Content

[0004] The present invention aims to provide a fixture for axial tensile testing of concrete specimens, in order to solve the problems of local stress concentration, specimen damage and test data deviation caused by bolts tightening the specimens in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a clamp for axial tensile testing of concrete specimens, comprising an upper clamping part and a lower clamping part, the upper clamping part comprising a first clamping block and a second clamping block, the first clamping block and the second clamping block being detachably connected, the upper part of the specimen being clamped between the first clamping block and the second clamping block; the lower clamping part comprising a third clamping block and a fourth clamping block, the third clamping block and the fourth clamping block being detachably connected, the lower part of the specimen being clamped between the third clamping block and the fourth clamping block.

[0006] The beneficial effects of this solution are as follows: This technical solution, through a split clamping structure consisting of clamping blocks one and two, and clamping blocks three and four, changes the traditional point-contact clamping of bolts to surface-contact clamping. This significantly reduces stress concentration at the clamping points of the specimen, effectively preventing damage to the specimen caused by excessive local stress. Simultaneously, the uniform force distribution and stable clamping state allow the LVDT to accurately reflect the displacement changes of the specimen during axial tensile testing, improving the accuracy and reliability of the mechanical property test results for high-ductility concrete.

[0007] Furthermore, the first clamping part also includes a first fastener. Both ends of the first clamping block are provided with vertical open circular holes, and the LVDT is installed in the open circular holes through the first fastener.

[0008] The beneficial effects of this solution are as follows: This technical solution enables precise installation and secure fixation of the LVDT. During use, align the LVDT with the open circular hole and adjust it to the appropriate position. Adjust the first fastener to close the opening and reduce the diameter of the circular hole until the LVDT is tightly clamped without any vertical slippage. This design ensures the LVDT remains stable during testing, avoiding displacement data fluctuations caused by LVDT loosening, thereby significantly improving the stability of displacement monitoring and the accuracy of measurement results in tensile tests.

[0009] Furthermore, the open circular hole includes a circular hole portion and an opening portion connected in sequence, the diameter of the circular hole portion is 19-22mm; the width of the opening portion is 4-6mm.

[0010] The beneficial effects of this solution are as follows: In this technical solution, the open circular hole adopts a structure in which the circular hole part and the opening part are connected in sequence. The diameter of the circular hole part is designed to be 19-22mm, and the width of the opening part is 4-6mm. This size combination can adjust the diameter of the circular hole part through the elastic deformation of the opening part, and achieve precise clamping of LVDT with the No. 1 fastener.

[0011] Furthermore, the No. 1 clamping block is provided with a No. 1 U-shaped hole, and the two sides opposite to the No. 1 U-shaped hole are provided with a No. 1 sliding groove. The two ends of the No. 2 clamping block are fixedly connected with a No. 1 slider, and the No. 1 slider is slidably set in the No. 1 sliding groove.

[0012] The beneficial effects of this solution are as follows: This technical solution involves setting a U-shaped hole on the first clamping block and opening a sliding groove on its two opposite sides. Simultaneously, a slider is fixedly connected to both ends of the second clamping block, allowing the slider to slide within the sliding groove. This structural design, when clamping the upper part of the test block, utilizes the guiding effect of the slider and the sliding groove to quickly and accurately position the second clamping block. This significantly simplifies the installation and disassembly process of the second and first clamping blocks, effectively improving the convenience and efficiency of the fixture.

[0013] Furthermore, the No. 3 clamping block is provided with the No. 2 U-shaped hole, and the two sides opposite to the No. 2 U-shaped hole are provided with the No. 2 sliding groove. The No. 4 clamping block is fixedly connected to the No. 2 slider at both ends, and the No. 2 slider is slidably set in the No. 2 sliding groove.

[0014] The beneficial effects of this solution are as follows: the No. 2 U-shaped hole of the No. 3 clamping block is provided with the No. 2 sliding groove on both sides. The No. 2 slider is fixed at both ends of the No. 4 clamping block and slides in cooperation with the sliding groove. Through the guiding and positioning structure of the slider and the sliding groove, the No. 4 clamping block can be quickly aligned when clamping the lower part of the test block, making the installation and disassembly process of the No. 4 clamping block and the No. 3 clamping block more convenient, effectively reducing the fixture assembly time and improving the operating efficiency.

[0015] Furthermore, the No. 1 clamping part also includes several No. 2 fasteners, and the No. 1 clamping block and the No. 2 clamping block are connected by the No. 2 fasteners.

[0016] The beneficial effects of this solution are as follows: The No. 1 clamping part achieves a detachable connection between the No. 1 clamping block and the No. 2 clamping block by setting the No. 2 fastener. This design allows for flexible adjustment of the clamping force according to the size of the test block. When the No. 2 fastener is tightened, the No. 1 clamping block and the No. 2 clamping block can be tightly attached to the upper part of the test block to form a stable surface contact clamping, avoiding stress concentration caused by the point contact of traditional bolts. When disassembling, only the No. 2 fastener needs to be loosened to quickly separate the No. 1 clamping block and the No. 2 clamping block. This not only ensures the reliability of the test block fixation, but also facilitates the disassembly and assembly of the fixtures before and after the test, significantly improving the convenience and practicality of the axial tensile test.

[0017] Furthermore, the second clamping part also includes several third fasteners, and the third clamping block and the fourth clamping block are connected by the third fasteners.

[0018] The beneficial effects of this solution are as follows: In this technical solution, the No. 2 clamping part achieves a detachable connection between the No. 3 clamping block and the No. 4 clamping block through the No. 3 fastener. This design allows for precise adjustment of the clamping force according to the size of the test block. When the No. 3 fastener is tightened, the No. 3 clamping block and the No. 4 clamp the lower part of the test block tightly, forming a uniform surface contact force state, avoiding local stress concentration and test block damage caused by traditional bolt tightening. When disassembling, simply loosen the No. 3 fastener to quickly separate the No. 3 clamping block and the No. 4 clamping block. This ensures the fixed stability of the test block in the axial tensile test and simplifies the disassembly and assembly process of the fixture, effectively improving the convenience of the test operation and the applicability of the clamping structure.

[0019] Furthermore, fasteners No. 1, No. 2, and No. 3 are all fastening bolts.

[0020] The beneficial effects of this scheme are as follows: using fastening bolts as fasteners No. 1, No. 2 and No. 3, and utilizing the adjustability of the threaded connection, the clamping force of the clamping block can be precisely controlled according to the thickness of the test block to form a uniform surface contact to avoid stress concentration. It also has the advantage of convenient disassembly and assembly, adapting to the test requirements of test blocks of different specifications. At the same time, the reliability of the bolt connection can ensure that the clamping structure remains stable during the tensile test. Attached Figure Description

[0021] Figure 1 This is a three-dimensional diagram of the prior art of this utility model;

[0022] Figure 2 This is a three-dimensional drawing of a clamp for axial tensile testing of concrete specimens according to the present invention.

[0023] Figure 3 This is a three-dimensional view of the upper clamping part of this utility model;

[0024] Figure 4 This is a three-dimensional view of the lower clamping part of this utility model. Detailed Implementation

[0025] The following detailed description illustrates the specific implementation method:

[0026] The reference numerals in the accompanying drawings include: upper clamping part 1, lower clamping part 2, test block 3, clamping block 1 4, clamping block 2 5, U-shaped hole 1 6, sliding groove 1 7, slider 1 8, round hole 9, opening 10, connecting hole 11, clamping block 3 12, clamping block 4 13, U-shaped hole 2 14, sliding groove 2 15, slider 2 16, upper clamping block 17, lower clamping block 18, through hole 19, bolt 20.

[0027] Example

[0028] A fixture for axial tensile testing of concrete specimens is basically as follows: Figure 1-4 As shown.

[0029] like Figure 2 The fixture shown is for axial tensile testing of concrete specimen 3, including an upper clamping part 1 and a lower clamping part 2, which are used to clamp the upper and lower parts of the specimen 3, respectively.

[0030] like Figure 3 As shown, the upper clamping part 1 includes a first clamping block 4, a second clamping block 5, two first fasteners, and two second fasteners. A first U-shaped hole 6 is formed on the upper side of the first clamping block 4, and a first sliding groove 7 is formed on both the left and right sides of the first U-shaped hole 6. A first slider 8 is integrally formed at both ends of the second clamping block 5. The first slider 8 is slidably disposed in the first sliding groove 7. The upper part of the test block 3 is clamped between the first clamping block 4 and the second clamping block 5. The first clamping block 4 and the second clamping block 5 are connected by the second fasteners. On the upper side of the first clamping block 4, there is an open circular hole on each of the left and right sides of the first U-shaped hole 6. The open circular hole includes a circular hole portion 9 and an opening portion 10 connected in sequence. The diameter of the circular hole portion 9 is 19-22mm; the width of the opening portion 10 is 4-6mm. Both ends of the front side of the first clamping block 4 are provided with connecting holes 11 that pass through the opening portion 10. The first fastener passes through the connecting holes 11 to fix the LVDT in the circular hole portion 9. In this embodiment, the diameter of the circular hole portion 9 is 20mm; the width of the opening portion 10 is 5mm.

[0031] like Figure 4 As shown, the lower clamping part 2 includes a third clamping block 12, a fourth clamping block 13, and two third fasteners. The third clamping block 12 has a second U-shaped hole 14 on its upper side, and second sliding grooves 15 are formed on both its left and right sides. The fourth clamping block 13 has two integrally formed second sliders 16 at both its left and right ends, which are slidably disposed within the second sliding grooves 15. The lower part of the test block 3 is clamped between the third clamping block 12 and the fourth clamping block 13, which are connected by the third fasteners. In this embodiment, the first, second, and third fasteners are all fastening bolts.

[0032] The specific implementation process is as follows:

[0033] First, the upper and lower parts of the test block 3 are fixed by the upper clamping part 1 and the lower clamping part 2 to ensure that the middle measuring section of the test block 3 is within the tensile range of the testing machine and is installed vertically without tilting; then, the LVDT is installed in the open round hole by the No. 1 fastener; finally, the axial tensile test is started, and the displacement change of the test block 3 is monitored in real time by the LVDT.

[0034] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A clamp for axial tensile testing of concrete specimens, characterized in that: It includes an upper clamping part and a lower clamping part. The upper clamping part includes a first clamping block and a second clamping block, which are detachably connected. The upper part of the test block is clamped between the first and second clamping blocks. The lower clamping part includes a third clamping block and a fourth clamping block, which are detachably connected. The lower part of the test block is clamped between the third and fourth clamping blocks.

2. The fixture for axial tensile testing of concrete specimens according to claim 1, characterized in that: The first clamping part also includes a first fastener. Both ends of the first clamping block are provided with vertical open round holes. The LVDT is installed in the open round holes through the first fastener.

3. A fixture for axial tensile testing of concrete specimens according to claim 2, characterized in that: The open circular hole includes a circular hole portion and an opening portion connected in sequence. The diameter of the circular hole portion is 19-22mm, and the width of the opening portion is 4-6mm.

4. A fixture for axial tensile testing of concrete specimens according to claim 3, characterized in that: The No. 1 clamping block is provided with a No. 1 U-shaped hole, and the two sides opposite to the No. 1 U-shaped hole are provided with a No. 1 sliding groove. The No. 2 clamping block is fixedly connected to the two ends of the No. 1 slider, and the No. 1 slider is slidably set in the No. 1 sliding groove.

5. A fixture for axial tensile testing of concrete specimens according to claim 4, characterized in that: The No. 3 clamping block is provided with the No. 2 U-shaped hole, and the two sides opposite the No. 2 U-shaped hole are provided with the No. 2 sliding groove. The No. 4 clamping block is fixedly connected to the No. 2 slider at both ends, and the No. 2 slider is slidably set in the No. 2 sliding groove.

6. A fixture for axial tensile testing of concrete specimens according to claim 5, characterized in that: The first clamping part also includes several second fasteners, and the first clamping block and the second clamping block are connected by the second fasteners.

7. A fixture for axial tensile testing of concrete specimens according to claim 6, characterized in that: The second clamping part also includes several third fasteners, and the third clamping block and the fourth clamping block are connected by the third fasteners.

8. A fixture for axial tensile testing of concrete specimens according to claim 7, characterized in that: Fastener No. 1, Fastener No. 2 and Fastener No. 3 are all fastening bolts.

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