Tensioning regulation and control device for mechanical property detection of prestressed material in laboratory

Abstract

The utility model discloses a tension regulation and control device for detecting the mechanical property of a prestressed material in a laboratory. The tension regulation and control device comprises a prestress adjustable and controllable bracket, an anchoring device and a distance measuring device, the prestress adjustable and controllable support comprises a screw rod and at least two top plates, the top plates are connected to the screw rod in a fastening mode through nuts, and the positions of the top plates on the screw rod are adjustable; the anchoring devices are used for fixing a test piece, the number of the anchoring devices is two, and each anchoring device abuts against the outer side of at least one top plate; and the distance measuring device is used for measuring the distance between any two points on the test piece between the two anchoring devices. The utility model provides the tension regulation and control device for detecting the mechanical property of the prestressed material in the laboratory, which is matched with the existing detection equipment in the laboratory for use, is small in size, convenient and fast to operate and accurate to control, and is used for realizing the prestressed coupling detection experiment of various types of materials.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the laboratory detection technical field of prestressed material, specifically relates to a kind of tension control device for laboratory prestressed material mechanics performance detection. BACKGROUND

[0002] With the continuous development of material field and engineering field technology, some high-performance new materials as new prestressed structural components, constantly realize innovative application in some construction engineering, such as fiber reinforced resin-based composite material. At present, the short / long-term performance detection and evaluation method of these new prestressed material components to replace existing structure needs to be researched and perfected to promote the further development and long-term safe application of new material components.

[0003] Traditional engineering material detection and evaluation method is mostly a kind of laboratory test method of mechanical property or one kind of mechanical property and environmental factor coupling. Based on the service characteristics of new prestressed structural component, it is urgent to carry out the experimental detection and evaluation technology of new material mechanical characteristics under prestressed coupling and comprehensive characteristics coupled with environmental factors, so as to more comprehensively evaluate the service characteristics of new prestressed structural material. At present, there is lack of prestressed tension control device for laboratory material detection. The prestressed material tension device in prior art is mostly used in prestressed engineering structure, and the anchoring and tension device corresponds to the matching large size prestressed component, which cannot be matched with existing laboratory detection equipment. If it is scaled down to a small size device by simple proportion, it cannot meet the precise control requirements of laboratory test small specimen tension.

[0004] Patent CN101851985B discloses a hinged anchor and prestressed tension method of high-strength fiber composite material sheet, and the tension device structure design and anchoring operation method are relatively complex, and the device matching tension instrument is jack, which cannot be operated on laboratory small test specimen, and the large tension stroke of jack cannot meet the precise control requirements of small tension stroke of small specimen.

[0005] Therefore, it is urgent to develop a tension control device for laboratory prestressed material mechanics performance detection, which is matched with laboratory conventional material performance detection testing machine, small in size, convenient to operate and accurate in control, to realize prestressed coupling detection experiment of various types of materials. UTILITY MODEL CONTENT

[0006] In order to solve the above technical problems, the utility model improves the prior art, optimizes the tension control device for prestressed material mechanics performance detection, and the specific scheme is as follows:

[0007] The utility model provides a kind of tensioning control device for laboratory prestressed material mechanical property detection, it is characterized in that, the tensioning control device includes prestressed adjustable support, anchoring device and range finder device;

[0008] The prestressed adjustable support includes screw rod and at least two top plates, the top plate is fastened and connected on screw rod by nut, and the position of top plate on screw rod is adjustable;

[0009] The anchoring device is used for fixing test piece, and the anchoring device is provided with two, and each anchoring device is at least abutted with the outside of one top plate;

[0010] The range finder device is used for measuring the distance between any two points on test piece between the two anchoring devices.

[0011] Further, at least two top plates are provided between the two anchoring devices.

[0012] Further, the anchoring device includes a clamp and a wedge-shaped clamp piece, the wedge-shaped clamp piece is arranged in the middle of the clamp, and the wedge-shaped clamp piece is tightly abutted with the test piece. The wedge-shaped clamp piece not only can ensure that the stress is uniformly distributed on the clamp, reduce local stress concentration, and avoid local damage caused by excessive stress, but also can gradually increase the surface friction between the wedge-shaped clamp piece and the test piece when stressed, to ensure that the test piece will not slip.

[0013] Further, the surface of the wedge-shaped clamp piece that is attached to the test piece is provided with corrugated protrusions.

[0014] The design of corrugated protrusions not only makes the surface of the wedge-shaped clamp piece not damaged due to excessive sharpness, but also can improve the friction between the wedge-shaped clamp piece and the test piece.

[0015] Further, the anchoring device is suitable for carbon fiber reinforced composite materials and other new prestressed structural materials with ultra-high tensile strength (> 3000Mpa) and other characteristics such as easy brittle fracture.

[0016] Further, the clamp has a rectangular cross section, and a square groove is arranged inside the clamp for placing the wedge-shaped clamp piece, to clamp the test piece with a rectangular cross section.

[0017] Preferably, the clamp uses two sets of clamping plates, and double-row connecting bolts are arranged on the clamping plates to fasten the overall clamping plate and ensure that the stress distribution at the clamping end is uniform.

[0018] Further, the inclination angle of the wedge-shaped clamp piece in the square groove is 1°-1.5°.

[0019] Preferably, when the required prestress for anchoring the test piece is less than 1000MPa, the inclination angle can be 1°.

[0020] Preferably, the angle of inclination is greater than 1° when the required prestress of the anchorage test piece is higher than 1000 MPa.

[0021] More preferably, the angle of inclination is 1.5° when the required prestress of the anchorage test piece is higher than 1000 MPa.

[0022] Further, the wedge-shaped clamping piece has a width of not more than 2 cm, a length of not more than 10 cm, and a maximum thickness of not more than 2 cm.

[0023] Further, the clamping piece has a circular cross section, and a circular channel matched with the wedge-shaped clamping piece is arranged inside the clamping piece for clamping a test piece with a circular cross section.

[0024] Preferably, the clamping piece is a circular sleeve.

[0025] Further, the angle of inclination of the wedge-shaped clamping piece in the circular channel is 1°.

[0026] Preferably, the number of wedge-shaped clamping pieces is two when the diameter of the test piece is not more than 5 mm.

[0027] Preferably, the number of wedge-shaped clamping pieces is more than two when the diameter of the test piece is greater than 5 mm.

[0028] More preferably, the number of wedge-shaped clamping pieces is three when the diameter of the test piece is greater than 5 mm, and the angle of inclination of the wedge-shaped clamping piece is 1°.

[0029] When the stress is too large or stress concentration is easy to crush the test piece; when the stress is too small or the stress clamping is insufficient, the anchoring device and the test piece are easy to slip during the tensioning process.

[0030] Further, the wedge-shaped clamping piece has a width of not more than 2 cm, a length of not more than 10 cm, and a maximum thickness of not more than 2 cm.

[0031] Further, a through hole for the test piece to pass through is arranged at the center of the top plate.

[0032] Further, the two anchoring devices are respectively close to the two ends of the test piece, and the test piece extends out of the anchoring device by a distance, facilitating the clamping of the two ends of the test piece by the universal testing machine.

[0033] Further, the screw rods are arranged on the four corners of the top plate, and the screw rods are arranged in parallel with the test piece.

[0034] Preferably, the number of screw rods is four.

[0035] Further, the nut includes an upper nut and a lower nut symmetrically arranged on both sides of the top plate for fastening the position of the top plate.

[0036] Preferably, the number of nuts on each top plate is 8, and the nuts are on the screw rod to ensure that the relative position of the top plate does not slip.

[0037] Further, the distance measuring device is selected from one of a strain gauge, a video extensometer, a full-automatic extensometer and a manual distance measuring device.

[0038] Preferably, the strain gauge is attached to the surface of the test specimen, and the lead wire is connected to the lead-out end of the strain gauge.

[0039] Preferably, the video extensometer or the full-automatic extensometer is used in cooperation with the universal testing machine to accurately measure the strain and displacement with the synchronous loading speed and load.

[0040] More preferably, the method of connecting the lead wire to the strain gauge cannot be realized in the environmental chamber; the video extensometer and the full-automatic extensometer must be used in cooperation with the universal testing machine.

[0041] Further, the manual distance measuring device includes but is not limited to a ruler and a vernier caliper, and any manual distance measuring device capable of measuring the length of the test specimen between the two anchoring devices is suitable for the utility model.

[0042] Further, the inner surface of the wedge-shaped clamping piece is additionally padded with sandpaper.

[0043] Further, the prestress adjustable support and the anchoring device are made of a quenched and tempered steel material.

[0044] Preferably, the prestress adjustable support and the anchoring device are made of a quenched and tempered 45 steel, which is not only corrosion-resistant and high-strength but also not easy to deform, and can meet the requirements of the overall placement of the environmental coupling test chamber of the tensioning control device.

[0045] The test material specimen includes various material specimens with a rectangular or circular cross section; the material types include metals, inorganic / organic materials and composite materials.

[0046] Preferably, there is a certain margin between the two top plates and the maximum range of the test specimen.

[0047] The basic principle of the prestressed system evaluation method is based on the stress / strain curve during the material tensioning and / or relaxation process, that is, the principle that the stress corresponding to different strains can be determined, and when the stress / strain curves during the material tensioning and relaxation process in the target stress range are consistent, only the tensioning stress / strain curve needs to be referred to.

[0048] The tensioning control device for laboratory prestressed material mechanical property detection is designed based on the principle of the prestressed system evaluation method.

[0049] Compared with the prior art, the tensioning control device for laboratory prestressed material mechanical property detection has the beneficial effects that:

[0050] 1. The tensioning control device for laboratory prestressed material mechanical property detection has a simple overall structure, small size, convenient operation, and can be used in cooperation with other test equipment in the laboratory to realize prestressed coupling performance testing of multiple types of laboratory material property testing machines.

[0051] 2. The tensioning control device for laboratory prestressed material mechanical property detection has a simple overall structure, small size, convenient operation, and can be used in cooperation with other test equipment in the laboratory to realize prestressed coupling performance testing of multiple types of laboratory material property testing machines.

[0052] 3. The tensioning control device for laboratory prestressed material mechanical property detection has a simple overall structure, small size, convenient operation, and can be used in cooperation with other test equipment in the laboratory to realize prestressed coupling performance testing of multiple types of laboratory material property testing machines.

[0053] 4. The tensioning control device for laboratory prestressed material mechanical property detection has a simple overall structure, small size, convenient operation, and can be used in cooperation with other test equipment in the laboratory to realize prestressed coupling performance testing of multiple types of laboratory material property testing machines. BRIEF DESCRIPTION OF DRAWINGS

[0054] The utility model will be described further below in combination with the drawings and examples, and the drawings are as follows:

[0055] Figure 1 It is the overall structure schematic diagram of tensioning control device;

[0056] Figure 2 It is the structure schematic diagram of one end of anchor device rectangular clamp;

[0057] Figure 3Right view of the rectangular clamp of the anchoring device;

[0058] Figure 4 This is a top view of the circular clamp of the anchoring device;

[0059] Figure 5 This is a schematic diagram of a wedge-shaped clip structure;

[0060] Figure 6 This is a schematic diagram of the overall structure of the tensioning control device in Example 1;

[0061] Figure 7 Figure 1 shows the impact damage effect of the prestressed specimen; Figure 2 shows the impact damage effect of the prestressed specimen; Figure 3 shows the impact damage effect of the specimen without prestress.

[0062] The reference numerals in the figure are as follows: 1-Prestressed adjustable support; 101-Screw; 102-Top plate; 103-Nut; 2-Anchoring device; 201-Clamp; 202-Wedge-shaped clamp; 203-Bolt; 204-Corrugated protrusion; 3-Specimen. Detailed Implementation

[0063] The present invention will be further described below with reference to the accompanying drawings and embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0064] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the appendix. Figure 1 The orientations or positional relationships shown are for ease of description and simplification of this utility model only, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0065] In the description of the utility model, it is necessary to explain that, unless there are explicit provisions and limitations, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, can be detachable connection, or integrally connected, can be mechanical connection, can be electrical connection, can be directly connected, can be indirectly connected through intermediate medium, can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood through specific circumstances.

[0066] The utility model provides a kind of tension control device for laboratory prestressed material mechanical property detection, the tension control device includes prestressed adjustable support 1, anchoring device 2 and range finder (not shown in drawing);

[0067] As Figure 1 As shown, the prestressed adjustable support 1 includes screw rod 101 and at least two top plates 102, the top plate 102 is fastened and connected on screw rod 101 by nut 103, and the position of top plate on screw rod is adjustable;The anchoring device 2 is used for fixing test piece, and anchoring device 2 is equipped with two, and each anchoring device 2 is at least with one top plate outside abutment, and the anchoring device is limited to slip by top plate, to prevent test piece shrinkage;The range finder is used for measuring the distance between any two points on test piece 3 between two described anchoring devices 2, and the pre-stress borne by test piece is determined by the distance change between any two points;The anchoring device 2 includes clamp 201 and wedge-shaped clamping piece 202, and the surface of wedge-shaped clamping piece 202 that is attached to test piece 3 is provided with corrugated protrusion 204.

[0068] As Figures 2-3 As shown, the clamp 201 section is rectangular, and square recess for placing wedge-shaped clamping piece 202 is arranged in the inside;The inclination angle of wedge-shaped clamping piece 202 in square recess is 1 °-1.5 °. Clamp 201 adopts a set of clamping plate, and double-row connecting bolt 203 is arranged on clamping plate.

[0069] When the required pre-stress of anchoring test piece is lower than 1000MPa, the inclination angle can be 1 °.

[0070] When the required pre-stress of anchoring test piece is higher than 1000MPa, the inclination angle is 1.5 °

[0071] The width of wedge-shaped clamping piece 202 is not more than 2cm;Length is not more than 10cm;Maximum thickness is less than or equal to 2cm.

[0072] The rectangular clamp 201 and the wedge-shaped clamp 202 installation steps: the convex end of the upper and lower wedge-shaped clamp is attached to the surface of the test material sample 3, the small head of the wedge-shaped clamp is inward, the large head is outward, then the wedge-shaped clamp 202 and the test material sample 3 are placed in the square groove of the clamp 201 as a whole. Finally, the relative position of the test material sample 3 and the wedge-shaped clamp 202 is adjusted, and the connecting bolt 203 is connected and fastened.

[0073] As shown in Figure 4 The clamp 201 is circular in cross section, and a circular channel matched with the wedge-shaped clamp 202 is arranged inside; the inclination angle of the wedge-shaped clamp 202 in the circular channel is 1°; the number of wedge-shaped clamps 202 is two or more. The clamp 201 adopts a circular sleeve.

[0074] When the diameter of the sample is less than or equal to 5mm, the number of wedge-shaped clamps 202 is two.

[0075] When the diameter of the sample is greater than 5mm, the number of wedge-shaped clamps 202 is more than two.

[0076] When the diameter of the sample is greater than 5mm, the number of wedge-shaped clamps 202 is three, and the inclination angle of the wedge-shaped clamp 202 is designed to be 1°

[0077] The circular clamp 201 and the wedge-shaped clamp 202 installation steps: the test material sample 3 is wrapped with the wedge-shaped clamp 202, and then a circular sleeve is sleeved, and the relative position of the test material sample 3 and the wedge-shaped clamp 202 is adjusted, the circular sleeve is tightened, and the fastening is completed.

[0078] The test material sample 3 and the anchoring device 2 are mechanically connected without glue joint process, which not only avoids the inconvenience brought by glue joint and the stress relaxation of glue joint which easily interferes with the overall analysis of the test, shortens the production cycle, but also effectively guarantees the efficiency of the anchoring device 2.

[0079] The top plate 102 is provided with a through hole in the center for the sample to pass through; two said anchoring devices 2 are respectively close to the two ends of the sample 3, and the two ends of the sample 3 extend out of the anchoring device 2 by a distance.

[0080] The screw rod 101 is arranged on the four corners of the top plate 102, and the screw rod 101 is arranged in parallel with the sample 3, and the number of the screw rod 101 is four; the nut 103 includes upper and lower nuts 103 symmetrically arranged on both sides of the top plate 102; the number of nuts 103 of each top plate 102 is eight.

[0081] The distance measuring device is selected from one of strain gauge, video extensometer, full-automatic extensometer and manual distance measuring device.

[0082] The inner surface of the wedge-shaped clamp 202 is also padded with sandpaper.

[0083] The prestressed adjustable support 1 and the anchoring device 2 are made of quenched and tempered steel.

[0084] The tension control device of this utility model is used in conjunction with a universal testing machine and an environmental coupling test chamber. In the test, the tension control device and universal testing machine of this application are used to apply prestress to the material to be tested, and then the environmental test chamber is used to conduct the prestress coupling experiment of the test material.

[0085] A universal testing machine is a device specifically designed for measuring the mechanical properties of materials. It integrates multiple functions such as tensile, bending, compression, and shear testing, and consists of a frame, clamps, and force sensors. By clamping the material to be tested with the upper and lower clamps of the universal testing machine and applying a certain tensile stress, the prestress applied to the material being measured can be accurately controlled.

[0086] The environmental coupling test chamber described in this application is an advanced testing device capable of simultaneously or sequentially applying multiple environmental factors, including high and low temperatures, water bath, seawater immersion, freeze-thaw cycles, and ultraviolet radiation. It is primarily used to evaluate the degradation patterns of tensile strength, flexural / shear strength, and impact resistance of test materials over a certain period. Furthermore, it allows for the prediction of the degree of performance degradation during long-term service of the test materials.

[0087] To better understand the technical solution of this utility model, the following specific implementation is used to illustrate the application of this utility model in mechanical performance tests such as multi-type environmental weathering resistance tests, impact resistance tests, and bending resistance tests of prestressed materials in the laboratory.

[0088] In this embodiment, the length of the test material specimen 3 is measured using a video extensometer. The video extensometer is used in conjunction with a universal testing machine. The camera of the video extensometer is vertically aligned with the test material specimen 3 to ensure that the camera's field of view covers the measurement area of ​​the test material specimen 3. At the same time, the optical axis of the camera should be parallel or perpendicular to the axis of the test material specimen 3 to reduce viewing angle errors.

[0089] Example 1

[0090] like Figure 6 As shown, in Example 1, the prestressed adjustable support 1 includes two top plates 102 and four screws 101, with eight nuts 103 on each top plate 102; the anchoring device 2 uses two sets of clamps, with wedge-shaped clamps 202 and the test material specimen 3 placed together in the square groove of the clamp 201. Both the prestressed adjustable support and the anchoring device used in Example 1 are made of heat-treated 45# steel.

[0091] S1. Mark two points at a certain distance on the test specimen 3 and record the distance between the two points L0 = 100mm;

[0092] S2. Adopt tension control device to fix the material specimen 3 to be tested: first, put the material specimen 3 to be tested into the top plate 102 of the prestressed adjustable support 1; then fix the two ends of the material specimen 3 to be tested in the prestressed adjustable support 1 by the anchoring device 2, and the two anchoring devices 2 are respectively located outside the two top plates 102; when the anchoring device 2 is fixed, the two ends of the material specimen 3 to be tested need to extend a certain position outside the anchoring device 2, and the extended part is used for reliable clamping on the universal testing machine;

[0093] S3. Fix the two ends of the material specimen 3 to be tested on the universal testing machine: adjust the relative position of the top plate 102 of the prestressed adjustable support 1, and loosen the nut 103 on the prestressed adjustable support 1; then place the whole tension control device on the universal testing machine, and fix the two ends of the material specimen 3 to be tested on the universal testing machine, and the two marked points are located between the two anchoring devices 2;

[0094] S4. Start the universal testing machine, and apply prestress to the material specimen 3 to be tested by adjusting the device parameters of the universal testing machine;

[0095] S5. When the prestress reaches the required value, keep the tension state of the universal testing machine, measure the distance L1 between the two points of the material specimen to be tested under the tension balance state of the universal testing machine by using the video extensometer, record the corresponding stress value F1 = 30kN, and draw the stress / strain curve of the material specimen to be tested according to L0, L1 and F1; (generally, F1 is within 60% of the maximum stress value Fmax of the material, F1 = (20% ~ 60%) Fmax, and Fmax is not more than 100kN)

[0096] S6. Adjust the two side top plates 102 of the tension control device to tightly abut the inner sides of the anchoring devices 2, tighten the upper and lower nuts 103 on the top plate, and make the top plate 102 tightly abut the anchoring device on the same side to keep the prestress applied to the material specimen 3 to be tested;

[0097] S7. Finally, unload the load of the universal testing machine, and when the material specimen 3 to be tested in the tension device is stable, measure the distance L2 between the two points of the material specimen 3 to be tested again by using the video extensometer, determine the actual prestress value F2 = 30kN according to the stress / strain curve, and then take out the tension control device together with the material specimen to be tested to which the prestress is applied from the universal testing machine;

[0098] S8. Confirm that the prestress of the tension control device is effectively controlled to more than 98%, and combine the material specimen to which the prestress is applied with the tension control device and the existing material performance test machine in the laboratory.

[0099] Prestressed impact resistance test:

[0100] Prestressed impact resistance test steps: according to the steps of example 1, prestress is applied to the test material specimen, the tension control device is placed on the test bench together with the prestressed test material specimen 3 fixed inside, and is stably connected with the placement table, and the prestressed material impact resistance test or the prestressed material bending resistance test and other mechanical property tests are carried out;

[0101] As shown in Figure 7 , the same material is used, the prestressed specimen and the non-prestressed specimen are respectively subjected to the impact resistance test, and the prestressed specimen and the non-prestressed specimen are respectively subjected to the impact resistance test. Figure 7 (a) and Figure 7 (b) The experimental results show that: under the same material, under the action of prestress and non-prestressed, under the action of different prestress, after being subjected to the same impact capacity, the impact damage resistance is significantly different.

[0102] Environmental resistance test:

[0103] Environmental resistance test steps: four same test material specimens are taken, prestress is applied to the test material specimen according to the steps of example 1, the tension control device is placed in the environmental test chamber together with the prestressed test material specimen 3 fixed inside, and the prestressed material environmental resistance test performance detection is carried out under different temperature conditions, the non-prestressed specimen is used as the control group, the prestressed material is subjected to the environmental resistance test under different temperatures for 30 min, and the experimental results in table 1 show that: under different prestressed materials under different temperatures, the tensile strength is obviously different.

[0104] Table 1 tensile strength test results of material specimen under different temperatures

[0105]

[0106] The above only describes the embodiments of the present application, and does not limit the patent range of the present application, any equivalent structural transformation or direct or indirect application in other related technical fields according to the content of the present application is also included in the patent protection range of the present application.

Claims

1. A tensioning control device for testing the mechanical properties of prestressed materials in a laboratory, characterized in that, The tensioning control device includes a prestressed adjustable support, an anchoring device, and a distance measuring device. The prestressed adjustable support includes a screw rod and at least two top plates. The top plates are fastened to the screw rod by nuts, and the position of the top plates on the screw rod is adjustable. The anchoring device is used to fix the specimen. There are two anchoring devices, and each anchoring device abuts against at least one outer side of the top plate. The distance measuring device is used to measure the distance between any two points on the specimen between the two anchoring devices.

2. The tensioning control device according to claim 1, characterized in that, The anchoring device includes a clamp and a wedge-shaped clip, and the surface of the wedge-shaped clip that fits against the specimen is provided with corrugated protrusions.

3. The tensioning control device according to claim 2, characterized in that, The clamp has a rectangular cross-section and a square groove inside for placing wedge-shaped clips; the inclination angle of the wedge-shaped clips in the square groove is 1°-1.5°.

4. The tensioning control device according to claim 2, characterized in that, The clamp has a circular cross-section and an internal circular channel that matches the wedge-shaped clamps; the inclination angle of the wedge-shaped clamps within the circular channel is 1°; and the number of wedge-shaped clamps is two or more.

5. The tensioning control device according to claim 1, characterized in that, The top plate has a through hole at its center for the specimen to pass through.

6. The tensioning control device according to claim 1, characterized in that, The screws are inserted at the four corners of the top plate and are parallel to the specimen.

7. The tensioning control device according to claim 6, characterized in that, The number of screws is 4.

8. The tensioning control device according to claim 1, characterized in that, The nuts include an upper nut and a lower nut symmetrically arranged on both sides of the top plate.

9. The tensioning control device according to claim 8, characterized in that, There are 8 nuts on each top plate.

10. The tensioning control device according to claim 1, characterized in that, The ranging device is selected from one of the following: strain gauge, video extensometer, fully automatic extensometer, and manual ranging device.

11. The tensioning control device according to claim 3 or 4, characterized in that, Sandpaper is padded on the inner surface of the wedge-shaped clip.

12. The tensioning control device according to any one of claims 1-9, characterized in that, The prestressed adjustable support and anchoring device are made of quenched and tempered steel.

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