Four-point bending test detection device for detecting sample deflection based on extensometer

Abstract

The utility model belongs to the field of building material detection, and discloses a four-point bending test detection device for detecting the deflection of a sample based on an extensometer, which comprises a fixed frame for fixing a concrete beam, and further comprises a moving device which is arranged on the fixed frame and can move along the length direction of the concrete beam to be detected, the lower measuring point is vertically arranged on the moving device; the upper measuring point is vertically arranged above the lower measuring point, the two measuring points are movably connected through a binding clamp, the top block is horizontally attached to the upper surface of the concrete beam to be measured, and one end of the top block is fixedly connected with the upper measuring point; the moving device moves to different detection points, the position heights of the top block at the different detection points are changed, so that the distance between the upper measuring point and the lower measuring point is changed, and the extensometer receives distance change parameters through the binding clamp to detect the deflection of the concrete beam.

Description

Technical Field

[0001] The utility model relates to the field of building material detection, in particular to a four-point bending test detection device based on an extensometer for detecting the deflection of a sample. Background Art

[0002] Traditional cement and concrete are both very important building materials in the main body of the current building structure and masonry structure, and concrete is formed on the basis of cement. However, these two building materials have defects such as heavy weight, poor tensile strength, high brittleness, and easy cracking, which seriously affect their application in engineering. With the development of materials science, many new types of concrete have emerged in modern architecture and civil engineering disciplines, such as steel fiber reinforced concrete, recycled concrete, and ultra-high strength concrete. This type of new concrete can effectively overcome the various shortcomings of traditional concrete, and all types of new concrete need to be tested for mechanical properties, compressive strength, splitting tensile strength, and flexural strength before entering actual engineering applications. The four-point bending test is the most common method of flexural strength testing because of its simple operation, intuitiveness, ease of operation, and high accuracy. It can well evaluate the advantages and disadvantages of concrete bending performance.

[0003] The four-point bending test equipment commonly used in laboratories is usually based on universal testing machines. However, different clamping devices for measuring the bending strength of concrete often have different defects. Different experimental schemes use different sizes of concrete beam specimens, and before loading, it is necessary to customize suitable fixtures according to the deflection measurement tools used. The above methods result in low test efficiency and high cost. However, if the appropriate fixture is not used, the concrete beam specimen will be offset during the loading process, which will affect the accuracy of the measurement results.

[0004] Mechanical extensometer is an accessory of universal testing machine. Selecting mechanical extensometer as deflection measurement tool and developing a concrete beam four-point bending test device adapted to it can solve the defect that the fixture is not universal, and has the advantages of improving test efficiency and saving costs. Summary of the invention

[0005] In view of the above problems, the utility model provides an experimental detection device that can combine a mechanical extensometer with a four-point bending test to detect the deflection of a specimen. The device can be adapted to specimens of different sizes and has good versatility. The specific scheme is as follows:

[0006] A four-point bending test detection device based on an extensometer to detect sample deflection includes a fixed frame for fixing a concrete beam, the fixed frame limits and fixes two sides of the concrete beam to be tested, and also includes:

[0007] A moving device, which is mounted on a fixed frame and can be displaced along the length direction of the concrete beam to be measured;

[0008] The lower measuring point is vertically mounted on the mobile device;

[0009] An upper measuring point, which is vertically arranged above the lower measuring point;

[0010] A clamp for the extensometer, which is clamped outside the upper measuring point and the lower measuring point, and the upper measuring point can move up and down in the clamp;

[0011] A top block is horizontally attached to the upper surface of the concrete beam to be measured, and one end of the top block is fixedly connected to the top of the upper measuring point;

[0012] The mobile device moves to different detection points, and the position height of the top block at different detection points changes, thereby changing the distance between the upper measuring point and the lower measuring point. The extensometer receives the distance change parameter through the clamp to detect the deflection of the concrete beam.

[0013] Furthermore, the fixing frame includes an arched clamp and a straight plate component, wherein there are two arched clamps, which are respectively located at both ends of the concrete beam, and two frame plates of each arched beam are respectively clamped on both sides of the end of the concrete beam to fix it;

[0014] The straight plate component includes two straight plates, namely a first straight plate and a second straight plate. The first straight plate and the second straight plate are respectively fixedly connected to the two clamping plates of the arch clamp by bolts. The first straight plate and the second straight plate are respectively clamped on both sides of the concrete beam to limit the two sides of the concrete beam.

[0015] Furthermore, the length of the straight plate corresponds to the length of the concrete beam, and limiting plates for clamping and limiting the ends of the concrete beam are respectively provided at both ends of the straight plate, and the limiting plates are detachably connected to the ends of the straight plate.

[0016] Furthermore, the moving device includes a sliding sleeve, which is sleeved on any of the straight plates and slides along the length direction of the straight plate. A horizontal boss is provided on the side of the sliding sleeve, and the lower measuring point is installed on the boss, and the preset boss corresponds to the neutral layer position of the concrete beam.

[0017] Furthermore, the length of the straight plate is adapted to the foundation size of the concrete beam required in the four-point bending test, and a length adjustment device that can adapt to concrete beams of different sizes is provided on the outer plate surface of the straight plate, and the length adjustment device includes two length adjustment plates, and the two length adjustment plates are symmetrically covered on the left and right plate surfaces of the straight plate respectively, and a slide groove is provided on the adjacent plate surfaces of the length adjustment plate and the straight plate, and the slide groove is arranged along the length direction of the length adjustment plate, and the straight plate is slidably connected to the slide groove, and the two length adjustment plates can slide and extend outwards of the two ends of the straight plate respectively, and the limit plate is installed on one end of the length adjustment plate that can extend out of the straight plate.

[0018] Furthermore, the slide groove is provided with a rack arranged along its length direction and a gear meshing with the rack, and the straight plate is installed with a gear shaft rotatably connected to the gear.

[0019] Furthermore, the length adjustment plate is provided with a plurality of length adjustment holes at equal intervals, and the length adjustment holes are fixed to the straight plate by bolts.

[0020] Furthermore, the two arch clamps are respectively fixedly connected to the length adjustment plates located at both ends of the concrete beam.

[0021] Furthermore, the upper measuring point and the lower measuring point are both columnar structures with the same cross-sectional shape, and the columnar structures are respectively a cylinder, a triangular prism and a quadrangular prism, which can match the binding clamp model of the extensometer.

[0022] Compared with the prior art, the advantages of the utility model are as follows:

[0023] 1. The utility model uses a fixed frame to limit and fix the two sides of the sample, and then drives the extensometer thereon through a moving device to perform a four-point bending test on the sample in the fixed frame. There is no need to specially make a matching fixture, and it has the advantages of good versatility and high experimental efficiency.

[0024] 2. The utility model provides a limit plate at the end of the straight plate, and fastens the two ends of the sample through the limit plate to avoid longitudinal displacement of the sample, thereby further improving the fixing effect of the sample.

[0025] 3. The utility model can adjust the length of the straight plate device by sliding the length adjustment plate to adapt to samples of various sizes, further improving the versatility of the device.

[0026] 4. The two pairs of length adjustment plates in the utility model adjust the length of the sample, the limit plate located at the end of the length adjustment plate clamps the end of the sample, the screw hole at the end of the straight plate is fixed to the corresponding length adjustment hole by bolts, the arch clamp is set at the end of the length adjustment plate, and the arch clamp is fixed to the corresponding angle adjustment hole, so that the movable range of the sliding sleeve is extended, and the extensometer increases more detection times in the extended moving area, thereby improving the measurement accuracy.

[0027] 5. The preset boss in the utility model corresponds to the neutral layer position of the concrete beam, and the purpose of reducing the deflection error is achieved by presetting the neutral layer position.

[0028] 6. The measuring point structure in the utility model is adapted according to the clamping model of the extensometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural diagram of the utility model;

[0030] Figure 2 It is a structural diagram of the fixed frame in the utility model;

[0031] Figure 3 This is a structural diagram of the length adjustment device in the utility model;.

[0032] Figure 4 Structural diagram of the sliding sleeve, lower measuring point, upper measuring point and top block in the utility model.

[0033] Figure 5 This is a structural diagram of the utility model after the length adjustment plate is extended to both ends;

[0034] Reference numerals:

[0035] 1-fixed frame, 11-arch clamp, 121-first straight plate, 122-second straight plate, 123-length adjustment plate, 124-length adjustment hole, 1231-slide groove, 1233-rack, 1234-gear, 21-lower measuring point, 211-slide sleeve, 212-boss, 22-upper measuring point, 221-top block, 223-cylindrical pressure head, 3-limiting plate. DETAILED DESCRIPTION

[0036] The technical solution of the utility model will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments.

[0037] Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the utility model.

[0038] In the description of the utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to has a specific orientation, is constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0039] In the description of the utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the utility model can be understood according to specific circumstances. Example

[0040] like Figure 1 As shown, a four-point bending test detection device based on an extensometer to detect the deflection of a sample includes a fixing frame 1 for fixing a concrete beam, wherein the fixing frame 1 is fixed to limit positions on both sides of the concrete beam to be tested.

[0041] like Figure 2 As shown, the fixed frame 1 includes an arch clamp 11 and a straight plate component, and the two frame plates of the arch clamp 11 are clamped on both sides of the concrete beam to fix it;

[0042] The straight plate component includes two straight plates, namely a first straight plate 121 and a second straight plate 122. The first straight plate 121 and the second straight plate 122 are respectively fixedly connected to the two clamping plates of the arch clamp 11. The first straight plate 121 and the second straight plate 122 are respectively clamped on both sides of the concrete beam to limit the positions of the two sides of the concrete beam.

[0043] There are two arch clamps 11, which are respectively installed at the two ends of the straight plate component. The clamp and the connected straight plate are respectively provided with aligned screw holes, and bolts for fixing are inserted into the two screw holes.

[0044] Also includes,

[0045] The moving device is mounted on the fixed frame 1 and can move along the length direction of the concrete beam to be tested. Figure 4 As shown, the moving device includes a sliding sleeve 211, and the sliding sleeve 211 is sleeved on any of the straight plates, and the sliding sleeve 211 slides along the length direction of the straight plate;

[0046] A lower measuring point 21, which is vertically mounted on the mobile device;

[0047] A horizontal boss 212 is provided on the side of the sliding sleeve 211, and the lower measuring point 21 is installed on the boss 212. Preferably, the boss 212 is threadedly connected to the lower measuring point 21, and a threaded hole with a diameter of 10 mm and a depth of 3 mm is provided at the center of the boss 212. A screw connected to the threaded hole is provided at the bottom of the lower measuring point 21, and the boss 212 is preset to correspond to the neutral layer position of the concrete beam;

[0048] An upper measuring point 22, which is vertically arranged above the lower measuring point 21;

[0049] The extensometer binding clamp is clamped outside the upper measuring point 22 and the lower measuring point 21, and the upper measuring point 22 can move up and down in the binding clamp;

[0050] The top block 221 is horizontally attached to the upper surface of the concrete beam to be measured. One end of the top block 221 is fixedly connected to the top of the upper measuring point 22. The top block 221 is a prism structure. The top block 221 and the upper measuring point 22 are threadedly connected. Figure 3 The columnar bodies located on both sides of the top block 221 are cylindrical pressure heads 223, which are imaginary objects for applying pressure to the top block 221. When the top block 221 is located at the removal detection point, pressure is applied to the top block 221 to press it downward;

[0051] The upper measuring point 22 and the lower measuring point 21 are both columnar structures with the same cross-sectional shape, and the columnar structures are respectively a cylinder, a triangular prism and a quadrangular prism, which can match the clamping model of the extensometer;

[0052] The mobile device moves to different detection points, and the position height of the top block 221 at different detection points changes, so that the distance between the upper measuring point 22 and the lower measuring point 21 changes. The extensometer receives the distance change parameter through the clamp to detect the deflection of the concrete beam.

[0053] The utility model fixes the two sides of the sample by the fixed frame 1, and then drives the extensometer thereon by the moving device to perform a four-point bending test on the sample in the fixed frame 1, without the need to specially make a matching fixture, and has the advantages of good versatility and high experimental efficiency. Example

[0054] The length of the straight plate corresponds to the length of the concrete beam. Limiting plates 3 for clamping and limiting the ends of the concrete beam are respectively provided at both ends of the straight plate. The limiting plates 3 are detachably connected to the ends of the straight plate.

[0055] The utility model provides a limiting plate 3 at the end of the straight plate, and fastens the two ends of the sample through the limiting plate 3 to avoid longitudinal displacement of the sample, thereby further improving the fixing effect of the sample. Example

[0056] like Figure 3 As shown, the length of the straight plate is adapted to the basic size of the concrete beam required in the four-point bending test. The basic size of the concrete beam is 300mm, and the size of each concrete beam increases gradually from 50mm to 500mm. A length adjustment device that can adapt to concrete beams of different sizes is provided on the outer plate surface of the straight plate. The length adjustment device includes two length adjustment plates 123, and the two length adjustment plates 123 are symmetrically covered on the left and right plate surfaces of the straight plate, respectively. A slide groove 1231 is provided on the adjacent plate surfaces of the length adjustment plate 123 and the straight plate, and the slide groove 1231 is arranged along the length direction of the length adjustment plate 123. The straight plate is slidably connected with the slide groove 1231, and the two length adjustment plates 123 can slide and extend outward from both ends of the straight plate respectively. The limit plate 3 is installed on the end of the length adjustment plate 123 that can extend out of the straight plate. The slide groove 1231 is provided with a rack 1233 arranged along its length direction and a gear 1234 meshing with the rack 1233 , and the straight plate is provided with a gear 1234 shaft rotatably connected to the gear 1234 .

[0057] The utility model can adapt to samples of various sizes by sliding the length adjustment plate 123 to adjust the length of the straight plate device, thereby further improving the versatility of the device. Example

[0058] like Figure 3 and Figure 5 As shown, the length adjustment plate 123 is provided with a plurality of length adjustment holes 124 spaced evenly apart, the length adjustment holes 124 are consistent with the aperture of the screw holes, and are fixed by inserting bolts into the two screw holes and the length adjustment holes 124. Each length adjustment plate 123 is provided with four length adjustment holes 124, the spacing between the length adjustment holes 124 is 25 mm, and the diameter is 10 mm.

[0059] The two pairs of length adjustment plates 123 in the utility model are used to adjust the length of the sample, the limit plate 3 located at the end of the length adjustment plate 123 clamps the end of the sample, the screw hole at the end of the straight plate is fixed to the corresponding length adjustment hole 124 by bolts, the arch clamp 11 is set at the end of the length adjustment plate 123, and the arch clamp 11 is fixed to the corresponding angle adjustment hole, so that the movable range of the sliding sleeve 211 is extended, and the extensometer increases more detection times in the extended moving area, thereby improving the measurement accuracy.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of each embodiment of the utility model.

Claims

1. A four-point bending test detection device based on an extensometer to detect the deflection of a sample, comprising a fixing frame (1) for fixing a concrete beam, wherein the fixing frame (1) is fixed at two sides of the concrete beam to be tested, and is characterized in that: Also includes, A moving device, which is mounted on the fixed frame (1) and can be displaced along the length direction of the concrete beam to be measured; A lower measuring point (21) is vertically mounted on the mobile device; An upper measuring point (22) is vertically arranged above the lower measuring point (21); A clamp for the extensometer, which is clamped outside the upper measuring point (22) and the lower measuring point (21), and the upper measuring point (22) can move up and down in the clamp; A top block (221) is horizontally attached to the upper surface of the concrete beam to be measured, and one end of the top block (221) is fixedly connected to the top of the upper measuring point (22); When the mobile device is displaced to different detection points, the position height of the top block (221) at the different detection points changes, thereby changing the distance between the upper measurement point (22) and the lower measurement point (21), and the extensometer receives the distance change parameter through the clamp to detect the deflection of the concrete beam.

2. The four-point bending test detection device based on the extensometer to detect the deflection of the sample according to claim 1 is characterized in that: The fixing frame (1) comprises an arch clamp (11) and a straight plate component, wherein there are two arch clamps (11), and the two arch clamps (11) are respectively located at the two ends of the concrete beam, and the two frame plates of each arch beam are respectively clamped on both sides of the end of the concrete beam to fix it; The straight plate component comprises two straight plates, namely a first straight plate (121) and a second straight plate (122). The first straight plate (121) and the second straight plate (122) are respectively fixedly connected to two clamping plates of the arch clamp (11) by bolts. The first straight plate (121) and the second straight plate (122) are respectively clamped on two sides of the concrete beam to limit the two sides of the concrete beam.

3. The four-point bending test detection device based on the extensometer to detect the deflection of the sample according to claim 2 is characterized in that: The length of the straight plate corresponds to the length of the concrete beam, and limiting plates (3) for clamping and limiting the ends of the concrete beam are respectively provided at both ends of the straight plate, and the limiting plates (3) are detachably connected to the ends of the straight plate.

4. The four-point bending test detection device based on the extensometer to detect the deflection of the sample according to claim 2 is characterized in that: The moving device comprises a sliding sleeve (211), the sliding sleeve (211) is sleeved on any of the straight plates, the sliding sleeve (211) slides along the length direction of the straight plate, a horizontal boss (212) is provided on the side of the sliding sleeve (211), the lower measuring point (21) is mounted on the boss (212), and the boss (212) is preset to correspond to the neutral layer position of the concrete beam.

5. The four-point bending test detection device based on the extensometer to detect the deflection of the sample according to claim 3 is characterized in that: The length of the straight plate is adapted to the size of the concrete beam foundation required in the four-point bending test. A length adjustment device capable of adapting to concrete beams of different sizes is provided on the outer plate surface of the straight plate. The length adjustment device comprises two length adjustment plates (123). The two length adjustment plates (123) are symmetrically covered on the left and right plate surfaces of the straight plate respectively. A slide groove (1231) is provided on the adjacent plate surfaces of the length adjustment plate (123) and the straight plate. The slide groove (1231) is arranged along the length direction of the length adjustment plate (123). The straight plate is slidably connected to the slide groove (1231). The two length adjustment plates (123) can slide and extend outwards of the two ends of the straight plate respectively. The limit plate (3) is installed on one end of the length adjustment plate (123) that can extend out of the straight plate.

6. The four-point bending test detection device based on the extensometer to detect the deflection of the sample according to claim 5 is characterized in that: The slide groove (1231) is provided with a rack (1233) arranged along its length direction and a gear (1234) meshing with the rack (1233), and the straight plate is provided with a gear (1234) shaft rotatably connected to the gear (1234).

7. The four-point bending test detection device based on the extensometer to detect the deflection of the sample according to claim 6 is characterized in that: The length adjustment plate (123) is provided with a plurality of length adjustment holes (124) at equal intervals, and the length adjustment holes (124) are fixed to the straight plate by bolts.

8. The four-point bending test detection device based on the extensometer to detect the deflection of the sample according to claim 7 is characterized in that: The two arched clamps (11) are respectively fixedly connected to the length adjustment plates (123) located at both ends of the concrete beam.

9. The four-point bending test detection device based on the extensometer to detect the deflection of the sample according to claim 1, characterized in that: The upper measuring point (22) and the lower measuring point (21) are both columnar structures with the same cross-sectional shape. The columnar structures are respectively a cylinder, a triangular prism and a quadrangular prism, and can match the binding clamp model of the extensometer.

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