Three-point bending experiment device for Hopkinson pressure bar system of recycled concrete large component

Abstract

The utility model discloses a three-point bending experiment device for a Hopkinson pressure bar system of a recycled concrete large component, which is skillfully characterized in that a limiting block is arranged on a machine table, and a pair of oppositely arranged fixed pressure head brackets is further arranged on one side surface of the limiting block; the movable pressure head connected with the incident bar of the Hopkinson pressure bar system is used for applying acting force to the sample (the sample between the movable pressure head and the fixed pressure head) on the bracket, so that the three-point bending test of the sample is convenient and reliable to implement; according to the scheme, a force sensor is further installed between the movable pressure head and the incident bar through a transition piece, so that when the incident bar applies acting force, test parameters can be recorded timely and efficiently through feedback of the force sensor.

Description

Technical Field

[0001] The utility model relates to the field of concrete performance testing devices, in particular to a three-point bending test device of a Hopkinson pressure bar system of a large recycled concrete component. Background Art

[0002] With the continuous development of social science and technology, the application of fracture mechanics in engineering has become quite common. In order to make fracture analysis of engineering structures, it is necessary to first obtain the fracture characteristic data of materials or structures through experiments, so as to better put science into practice. The scope of fracture tests is very wide. According to the scale of the test, fracture tests can be divided into small laboratory tests, large laboratory tests and actual structural tests; according to the loading speed, they can be divided into static tests and dynamic tests; according to the test environment, they can be divided into high temperature, low temperature and tests containing corrosive media; according to the loading method, they can be divided into tensile and bending tests, etc. Among them, the three-point bending test is the most widely used one in fracture toughness testing, and it is named because the specimen is subjected to three-point bending loading in the test.

[0003] The overall operation process and concept of the current three-point bending experiment have been perfected, but its physical experimental structure still has certain defects: on the one hand, there is currently no three-point bending test device that can be applied to the Hopkinson pressure bar (SHPB) system; on the other hand, the current test device cannot install the force sensor on the Hopkinson pressure bar (SHPB) system and can directly collect the relationship curve between force and time.

[0004] Some researchers have designed and improved some three-point bending experimental devices to study the fracture characteristics of materials, such as the following:

[0005] (1) Ren Li and others, inventors of Chinese patent application CN201910264386.X, invented a rock three-point bending fixture for size effect testing. When in use, first use springs and bolts to fix the two rollers on the movable support, and also use springs and bolts to fix the pressure roller on the pressure head. Then, the entire support part is placed on the operating platform of the test machine, and the pressure head body is connected to the sensor of the test machine. Then, the position of the movable support is determined by a ruler, and then the processed rock specimen is placed, and the sensor and the pressure head part are slowly lowered to 1-2mm away from the test component. Finally, the rock specimen is subjected to a load test. The test machine records the load, displacement and other data during the experiment in real time until the specimen breaks and the test ends. The device can meet the needs of three-point bending tests for groups of specimens with large size changes by detachably replacing the pressure roller and the support roller, and the model of the roller can be changed. In addition, the bottom support is movable, which can explore the size effect of rocks.

[0006] (2) The inventors of Chinese patent application CN202010990976.3, Shen Wenhao and others, designed a static semi-circular disk three-point bending fracture toughness measurement device under temperature and pressure environment. The device places the pressure head and support for three-point bending in a pressure autoclave. The inner wall of the pressure autoclave is covered with insulating material and heating wire to increase the temperature. A servo pump is used to pump gas or liquid to increase the pressure. The temperature and pressure in the autoclave are controlled in real time through temperature and pressure sensors. The device can measure the fracture toughness of materials under controllable temperature and pressure environment and simulate the real environment in which the materials are located.

[0007] (3) Luo Mingxiao, the inventor of Chinese patent application CN202320617030.1, designed a concrete fracture toughness testing device. The device can automatically transport concrete. The automatic transport mechanism is arranged on one side of the three-point bending mechanism, which is used to automatically transport concrete to the three-point bending mechanism. The top surface of the mounting plate in the automatic transport mechanism is flush with the top of the support roller, and the push plate and the first drive guide rail in the push assembly are arranged. When the concrete block is placed on the mounting plate, the push plate can smoothly push the concrete from the mounting plate to the support rod along the axis direction of the support roller, thereby realizing automatic transport of concrete and effectively avoiding the loss caused by manual transport.

[0008] (4) Wang Kaiqing, the inventor of Chinese patent application CN202211295797.3, invented a three-point bending specimen low-temperature fracture toughness test device and method. The low-temperature fracture toughness test of the three-point bending specimen is carried out by using the first indenter, the second indenter, the first indenter extension rod, the second indenter extension rod, and the knife edge formed between one end of the second indenter extension rod and the other end of the first indenter extension rod, which meets the need for miniaturization of the three-point bending specimen in irradiation supervision within the limited in-pile irradiation space.

[0009] (5) Li Geping et al., inventors of Chinese patent application CN202311416297.5, designed an experimental device and method for three-point bending of ultra-thin samples. When conducting the experiment with this device, the left side of the sample stage and the right side of the sample stage are first connected together; then, the ultra-thin bending samples and a number of pads of suitable sizes used in the experiment are prepared; then, the obtained bending samples and pads are placed between the connected left side of the sample stage and the right side of the sample stage; finally, the obtained combination is placed on the base, the position of the pressure head is adjusted, and the bending experiment is started. The device has a simple structure. It is easy to operate and can also realize ultra-low temperature three-point bending experiments.

[0010] (6) Qu Bin, the inventor of Chinese patent application CN202210740305.0, designed an automatic centering fixture for three-point bending experiments. The device can achieve relative displacement of two first sliders by rotating the first screw to clamp the material to be fixed, and the sliding speed of the two first sliders is the same, so as to achieve automatic positioning and clamping of the material. When the first screw is continuously rotated, the clamping plate will be displaced to fix the material more tightly. The two relatively moving clamping boxes will fix the two ends of the material, thereby achieving automatic centering of the experimental material.

[0011] Based on the above, it can be seen that the existing technology still has the following limitations:

[0012] (1) Most of the current three-point bending devices are used in static load tests, while the present invention can be applied in dynamic load tests.

[0013] (2) The Hopkinson Pressure Bar (SHPB) system cannot currently be used in conjunction with a force sensor. Summary of the invention

[0014] In view of this, the purpose of the utility model is to provide a three-point bending test device of a large recycled concrete member Hopkinson pressure bar system which has a simple structure, reliable implementation and can combine a force sensor with a Hopkinson pressure bar (SHPB) system.

[0015] In order to achieve the above technical objectives, the technical solution adopted by the utility model is:

[0016] A three-point bending test device of a Hopkinson pressure bar system of a large recycled concrete component, comprising a machine platform, an incident rod and a sample clamping and limiting assembly, wherein the sample clamping and limiting assembly comprises:

[0017] A limit block, fixedly arranged on the machine platform;

[0018] A pair of fixed pressure heads are relatively detachably connected to one side of the limit block;

[0019] A movable pressure head is arranged on one side of the limit block and is offset and opposite to the pair of fixed pressure heads;

[0020] A sliding mechanism is arranged below the movable pressure head and fixed to the machine platform. The sliding mechanism is connected to the movable pressure head so that the movable pressure head can slide in a direction close to or away from the limit block. A test area for clamping a sample is formed between the movable pressure head and a pair of fixed pressure heads. A side of the movable pressure head away from the limit block is used to cooperate with the incident rod. The incident rod applies a force to cause the sample clamped in the test area to be subjected to force.

[0021] The sensor is arranged on a side of the movable pressure head away from the limit block and is used to sense the pressure value of the force applied by the incident rod.

[0022] As a possible implementation manner, further, in this solution, a projection of the movable pressing head on a side surface of the limiting block is located between the pair of fixed pressing heads.

[0023] As a possible implementation manner, further, a bracket having an L-shaped structure and used for holding a sample is detachably provided below a pair of the fixed pressure heads at a lower portion of one side of the limit block described in the present embodiment.

[0024] As a possible implementation manner, further, the other side surface of the limit block in this solution is also fixedly connected to a support block, and the support block is also fixedly connected to the machine platform.

[0025] As a possible implementation mode, further, a positioning key protruding outward and extending to both sides of the limit block is provided on one side surface of the limit block of the present invention, and a pair of fixed pressure heads are provided with positioning grooves corresponding to the positioning keys, and cooperate with the positioning keys through the positioning grooves.

[0026] As a preferred implementation mode, preferably, in this solution, a pair of fixed pressure heads are detachably connected to one side surface of the limit block by bolts.

[0027] As a preferred embodiment, preferably, in this solution, the cross-section of the pair of fixed pressure heads is T-shaped, and the T-shape has positioning grooves on one side at both ends, and the single end side of the T-shape is used to contact the sample.

[0028] As a preferred embodiment, the movable pressure head described in this scheme is a cylindrical structure with one end closed, and an extension portion for contacting the sample is provided on the closed end; the cylindrical structure end of the movable pressure head is connected to the sensor through a transition piece, and the incident rod cooperates with the transition piece.

[0029] As a preferred embodiment, preferably, the sensor in this solution is a column force sensor, and the transition piece includes:

[0030] A first transition joint, which is arranged in the cylindrical structure of the movable pressure head, and has a first positioning groove on an end surface thereof away from the limiting member, and one end of the sensor is inserted into the first positioning groove;

[0031] A second transition joint, one end surface of which is provided with a second positioning groove, the other end of the sensor is inserted into the second positioning groove, and the other end surface of the second transition joint is provided with a third positioning groove, the third positioning groove is matched with the end of the incident rod;

[0032] The outer peripheral side of the movable pressure head is provided with a first locking bolt which is threaded into the cylindrical structure thereof and is used to clamp and fix the first transition joint in the cylindrical structure of the movable pressure head;

[0033] A second locking bolt is provided on the outer circumference of the second transition joint and is threadedly inserted into the second transition joint and is used to clamp and fix the end of the incident rod in the third positioning groove.

[0034] As a preferred implementation mode, preferably, the first positioning groove and the second positioning groove in this solution are contoured positioning grooves respectively adapted to the structures at both ends of the force sensor.

[0035] As a preferred embodiment, the sliding mechanism of this solution preferably includes:

[0036] A base, fixedly arranged on the machine platform, wherein the upper end surface of the base is provided with a guide rail;

[0037] A slide seat, the lower end surface of which is connected to a slider, the lower end surface of the slider is provided with a slide groove that matches the guide rail, and the slide seat is slidably connected to the guide rail through the slider;

[0038] A connecting block has one end fixed on the upper end surface of the slide seat and the other end connected to the movable pressure head; the incident rod drives the movable pressure head and the slide seat to slide on the guide rail.

[0039] As a preferred embodiment, preferably, a pair of relatively fixed restraining blocks for limiting the sliding of the slide are provided at both ends of the base described in this solution.

[0040] By adopting the above-mentioned technical scheme, the utility model has the following beneficial effects compared with the prior art: the device of this scheme cleverly arranges a limit block on the machine platform, further arranges a pair of relatively arranged fixed pressure head brackets on one side of the limit block, and then applies a force to the sample on the bracket (the sample between the movable pressure head and the fixed pressure head) through the movable pressure head connected to the incident rod of the Hopkinson pressure bar system, so that the three-point bending test of the sample is not only convenient and reliable to implement, but also the scheme further installs a force sensor between the movable pressure head and the incident rod through a transition piece, so that when the incident rod applies a force, the test parameters can be recorded timely and efficiently through the feedback of the force sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 This is one of the three-dimensional perspective diagrams of the simplified implementation structure of the device of this scheme;

[0043] Figure 2 This is one of the three-dimensional perspective schematic diagrams of the simplified implementation structure of the sample clamping and limiting assembly of the device of this scheme;

[0044] Figure 3 This is the second three-dimensional perspective schematic diagram of the simplified implementation structure of the sample clamping and limiting assembly of the device of this scheme;

[0045] Figure 4 This is one of the three-dimensional exploded schematic diagrams of the simplified implementation structure of the sample clamping and limiting assembly of the device of this scheme;

[0046] Figure 5 It is a schematic diagram of the simplified matching structure of the limit block, fixed pressure head and bracket of the device of this scheme;

[0047] Figure 6 It is a schematic diagram of the simplified matching structure of the movable pressure head, transition piece and incident rod of the device of this scheme. DETAILED DESCRIPTION

[0048] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is particularly noted that the following embodiments are only used to illustrate the present invention, but do not limit the scope of the present invention. Similarly, the following embodiments are only partial embodiments of the present invention rather than all embodiments. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] Combination Figures 1 to 6 As shown in one of the embodiments, a three-point bending test device of a Hopkinson pressure bar system of a large recycled concrete component includes a machine platform 1, an incident rod 2 and a sample clamping and limiting assembly 3, wherein the sample clamping and limiting assembly includes:

[0050] A limit block 31 is fixedly arranged on the machine platform 1;

[0051] A pair of fixed pressure heads 32 are relatively detachably connected to one side surface of the limit block 31;

[0052] The movable pressing head 33 is arranged on one side of the limiting block 31 and is offset and opposite to the pair of fixed pressing heads 32;

[0053] A sliding mechanism 34 is disposed below the movable ram 33 and fixed to the machine platform 1. The sliding mechanism 34 is connected to the movable ram 33 so that the movable ram 33 can slide in a direction close to or away from the limit block 31. A test area for clamping the sample 4 is formed between the movable ram 33 and a pair of fixed rams 32. The side of the movable ram 33 away from the limit block 31 is used to cooperate with the incident rod 2. The incident rod 2 applies a force to make the sample 4 clamped in the test area subject to force.

[0054] The sensor 35 is disposed on a side of the movable pressure head 33 away from the limit block 31 and is used to sense the pressure value of the force applied by the incident rod 2 .

[0055] In this solution, as a three-point complete experiment, the projection of the movable pressure head 33 on one side of the limit block 31 is located between the pair of fixed pressure heads 32 .

[0056] In order to facilitate the placement of the sample 4 and prevent it from falling due to gravity, as a possible implementation method, further, a bracket 36 with an L-shaped structure and used to support the sample is detachably provided under a pair of the fixed pressure heads 32 at the lower part of one side of the limit block 31 described in this scheme.

[0057] In order to prevent the limit block 31 from being displaced due to force transmission when the incident rod 2 applies a force to the sample 4, as a possible implementation mode, further, the other side of the limit block 31 described in the present scheme is also fixedly connected to a support block 311, and the support block 311 is also fixedly connected to the machine 1.

[0058] In order to facilitate the installation of the fixed pressure head 32, as a possible implementation method, further, a positioning key 313 protruding outward and extending to both sides of the limit block is provided on one side surface of the limit block 31 described in this scheme, and a pair of the fixed pressure heads 32 are provided with positioning grooves 321 corresponding to the positioning keys 313, and cooperate with the positioning keys 313 through the positioning grooves 321. In this scheme, the positioning key 313 can be set on one side surface of the limit block 31 in the form of a detachable connection, and an installation groove 312 is provided on one side surface of the limit block 31 corresponding to the positioning key 313.

[0059] In addition, as a preferred embodiment, preferably, in this solution, the pair of fixed pressure heads 32 are removably connected to one side surface of the limit block 31 by bolts; preferably, in this solution, the cross-sections of the pair of fixed pressure heads 32 are T-shaped, and the T-shape has a positioning groove 321 on one side at both ends, and the single end side of the T-shape is used to contact the sample 4.

[0060] As a preferred embodiment, the movable pressure head 33 of the present invention is a cylindrical structure 332 with one end closed, and an extension portion 331 for contacting the sample 4 is provided on the closed end; the end of the cylindrical structure 332 of the movable pressure head 33 is connected to the sensor 35 through a transition piece 37, and the incident rod 2 cooperates with the transition piece 37; as a preferred embodiment, the sensor 35 of the present invention is a columnar force sensor, and the transition piece 37 includes:

[0061] The first transition joint 371 is arranged in the cylindrical structure of the movable pressure head 33, and a first positioning groove 3711 is arranged on an end surface thereof away from the limiting member, and one end of the sensor is inserted into the first positioning groove 3711;

[0062] A second transition joint 372, one end surface of which is provided with a second positioning groove, the other end of the sensor is inserted into the second positioning groove, and the other end surface of the second transition joint is provided with a third positioning groove 3721, the third positioning groove 3721 is matched with the end of the incident rod 2;

[0063] The outer peripheral side of the movable pressure head 33 is provided with a first locking bolt 333 which is threaded into the cylindrical structure thereof and is used to clamp and fix the first transition joint 371 in the cylindrical structure 332 of the movable pressure head 33;

[0064] A second locking bolt 3722 is provided on the outer circumference of the second transition joint 372 , which is threadedly inserted into the second transition joint 372 and is used to clamp and fix the end of the incident rod 2 in the third positioning groove 3721 .

[0065] In order to facilitate the installation of the sensor 35 and avoid abnormalities such as dislocation and uneven force due to force, as a preferred implementation method, preferably, the first positioning groove 3711 and the second positioning groove in this scheme are contoured positioning grooves respectively adapted to the structures at both ends of the force sensor.

[0066] On the basis of the above, as a preferred embodiment, preferably, the sliding mechanism 34 of this solution includes:

[0067] A base 341 is fixedly disposed on the machine platform 1, and a guide rail 342 is disposed on the upper end surface of the base 341;

[0068] The sliding seat 343 has a slider 344 connected to its lower end surface. The slider 344 has a sliding groove matched with the guide rail 342 on its lower end surface. The sliding seat 343 is slidably connected to the guide rail 342 through the slider 344.

[0069] The connecting block 346 has one end fixed to the upper end surface of the slide seat 343 and the other end connected to the movable pressing head 33 ; the incident rod 2 drives the movable pressing head 33 and the slide seat 343 to slide on the guide rail 342 .

[0070] In order to prevent the slide 343 from slipping off the guide rail 342 on the base 341, as a preferred embodiment, preferably, a pair of relatively fixed constraint blocks 345 for limiting the sliding of the slide 343 are provided at both ends of the base 341 described in this solution.

[0071] By adopting the above-mentioned scheme, when performing a three-point bending test on the sample 4, it is only necessary to place the sample 4 on a pair of the brackets 36, and then fix the incident rod 2 on the second transition joint, and push the movable pressure head 33 through the incident rod 2, so that the sample 4 is subjected to three-point forces applied to it by the movable pressure head 33 and a pair of fixed pressure heads 32, and then the sensor 35 is used to sense the magnitude of the force applied by the incident rod 2, so as to form a data association record.

[0072] The above descriptions are only some embodiments of the present invention, and do not limit the protection scope of the present invention. Any equivalent device or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A three-point bending test device of a large recycled concrete component Hopkinson pressure bar system, comprising a machine platform, an incident rod and a sample clamping and limiting assembly, characterized in that: The sample clamping and limiting assembly comprises: A limit block, fixedly arranged on the machine platform; A pair of fixed pressure heads are relatively detachably connected to one side of the limit block; A movable pressure head is arranged on one side of the limit block and is offset and opposite to the pair of fixed pressure heads; A sliding mechanism is arranged below the movable pressure head and fixed to the machine platform. The sliding mechanism is connected to the movable pressure head so that the movable pressure head can slide in a direction close to or away from the limit block. A test area for clamping a sample is formed between the movable pressure head and a pair of fixed pressure heads. A side of the movable pressure head away from the limit block is used to cooperate with the incident rod. The incident rod applies a force to cause the sample clamped in the test area to be subjected to force. The sensor is arranged on a side of the movable pressure head away from the limit block and is used to sense the pressure value of the force applied by the incident rod.

2. The three-point bending test device of the Hopkinson strut system of recycled concrete large components as claimed in claim 1 is characterized in that: The projection of the movable pressure head on one side of the limit block is located between the pair of fixed pressure heads; A bracket having an L-shaped structure and used for holding the sample is detachably provided below a pair of the fixed pressure heads at the lower part of one side of the limit block; The other side surface of the limit block is also fixedly connected with a support block, and the support block is also fixedly connected to the machine platform.

3. The three-point bending test device of the Hopkinson strut system of recycled concrete large components as claimed in claim 1 is characterized in that: A positioning key which protrudes outward and extends to both sides of the limiting block is provided on one side surface of the limiting block, and a pair of the fixed pressure heads are provided with positioning grooves corresponding to the positioning keys, and cooperate with the positioning keys through the positioning grooves.

4. The three-point bending test device of the Hopkinson strut system of recycled concrete large components as claimed in claim 3 is characterized in that: A pair of fixed pressure heads are detachably connected to one side surface of the limit block by bolts.

5. The three-point bending test device of the Hopkinson strut system of recycled concrete large components as claimed in claim 3 is characterized in that: The cross-sections of the pair of fixed pressure heads are both T-shaped, and one side of the two ends of the T-shape is provided with a positioning groove, and the single end side of the T-shape is used for contacting with the sample.

6. The three-point bending test device of the Hopkinson strut system of recycled concrete large components according to any one of claims 1 to 5, characterized in that: The movable pressure head is a cylindrical structure with one end closed, and an extension part for contacting the sample is provided on the closed end; the cylindrical structure end of the movable pressure head is connected to the sensor through a transition piece, and the incident rod cooperates with the transition piece.

7. The three-point bending test device of the Hopkinson strut system of recycled concrete large components as claimed in claim 6 is characterized in that: The sensor is a column force sensor, and the transition piece comprises: A first transition joint, which is arranged in the cylindrical structure of the movable pressure head, and has a first positioning groove on an end surface thereof away from the limit block, and one end of the sensor is inserted into the first positioning groove; A second transition joint, one end surface of which is provided with a second positioning groove, the other end of the sensor is inserted into the second positioning groove, and the other end surface of the second transition joint is provided with a third positioning groove, the third positioning groove is matched with the end of the incident rod; The outer peripheral side of the movable pressure head is provided with a first locking bolt which is threaded into the cylindrical structure thereof and is used to clamp and fix the first transition joint in the cylindrical structure of the movable pressure head; A second locking bolt is provided on the outer circumference of the second transition joint and is threadedly inserted into the second transition joint and is used to clamp and fix the end of the incident rod in the third positioning groove.

8. The three-point bending test device of the Hopkinson strut system of recycled concrete large components as claimed in claim 7, characterized in that: The first positioning groove and the second positioning groove are contoured positioning grooves respectively adapted to the structures at both ends of the force sensor.

9. The three-point bending test device of the Hopkinson strut system of recycled concrete large components as claimed in claim 7, characterized in that: The sliding mechanism comprises: A base, fixedly arranged on the machine platform, wherein the upper end surface of the base is provided with a guide rail; A slide seat, the lower end surface of which is connected to a slider, the lower end surface of the slider is provided with a slide groove that matches the guide rail, and the slide seat is slidably connected to the guide rail through the slider; A connecting block has one end fixed on the upper end surface of the slide seat and the other end connected to the movable pressure head; the incident rod drives the movable pressure head and the slide seat to slide on the guide rail.

10. The three-point bending test device of the Hopkinson strut system of recycled concrete large components as claimed in claim 9, characterized in that: A pair of relatively fixed restraining blocks for limiting the sliding of the slide seat are also provided at both ends of the base.

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