Shearing creep test loading device

Abstract

The utility model discloses a shear creep test loading device which comprises a supporting bottom plate, two steel stand columns, a steel beam, a test piece fixing rear steel plate, a test piece fixing front steel plate and a loading mechanism, the two steel stand columns are installed on the supporting bottom plate, and the upper ends of the two steel stand columns are connected through the steel beam. The front end face of the steel beam is fixedly connected with a test piece fixing rear steel plate, the front end of the test piece fixing rear steel plate is connected with a test piece, the front end of the test piece is connected with a test piece fixing front steel plate, the test piece fixing front steel plate is connected with a loading mechanism, and the loading mechanism is used for applying shearing force to the test piece. According to the utility model, the shear creep test environment of the sandwich layer of the composite material is simulated, and the loading mechanism is adopted to directly apply shear force on the test surface of the test piece, so that the problems that the shear creep test loading of the sandwich layer is difficult, and shear creep performance data can only be obtained through an indirect way are solved; and the shear creep performance of a plurality of test pieces can be respectively and independently tested at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of mechanical performance testing devices, in particular to a shear creep testing loading device. Background Art

[0002] The sandwich layer of the composite sandwich structure is often made of foam, balsa wood, etc., and the matrix in the surface layer is often made of epoxy resin, unsaturated polyester resin, etc. Because foam, balsa wood, resin, etc. are all viscoelastic materials, the composite sandwich structure composed of them will also show viscoelasticity. When the composite sandwich structure is subjected to long-term constant load, viscoelastic deformation, namely creep, will occur. The occurrence of creep will affect the dimensional stability of the composite structure and reduce its safety during long-term service. At present, composite sandwich structures have been successfully applied to various types of civil infrastructure construction such as bridge panels and floor panels. Against the background of the continuous expansion of the application scope of composite sandwich structures, conducting various creep performance studies on them will be conducive to improving the reliability of the structure during service.

[0003] When used as bridge decks and floor decks, composite sandwich structures mainly bear bending loads, and their components, namely the upper layer, lower layer and sandwich layer, respectively play a role in compression, tension and shear resistance. Therefore, the creep performance test of the composite sandwich structure includes the bending creep performance test of the entire structure, the tensile and compression creep performance test of the surface layer, and the shear creep performance test of the sandwich layer. Compared with the bending, tensile and compression creep performance tests, the shear creep performance test load of the sandwich layer is somewhat difficult to apply. At present, indirect testing methods are often used to obtain the shear creep performance data of the sandwich layer, but the measured shear creep performance data of the sandwich layer cannot guarantee accuracy because it is an indirect measurement.

[0004] Therefore, a shear creep test loading device is urgently needed to solve the problem of inconvenience in directly measuring the shear creep performance data of the sandwich layer. Utility Model Content

[0005] The utility model aims at the deficiencies in the prior art and provides a shear creep test loading device to solve the problem of inconvenience in directly measuring the shear creep performance data of the sandwich layer.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A shear creep test loading device, characterized in that it includes a supporting base plate, steel columns, steel beams, a specimen fixing rear steel plate, a specimen fixing front steel plate and a loading mechanism, wherein two steel columns are installed on the supporting base plate, the upper ends of the two steel columns are connected by a steel beam, a specimen fixing rear steel plate is fixedly connected to the front end surface of the steel beam, a specimen is connected to the front end of the specimen fixing rear steel plate, a specimen is connected to the front end of the specimen fixing rear steel plate, a specimen is connected to the front end of the specimen fixing front steel plate, the specimen fixing front steel plate is connected to the loading mechanism, and the loading mechanism is used to apply shear force to the specimen.

[0008] To optimize the above technical solutions, the specific measures taken also include:

[0009] Furthermore, a steel groove which is turned inwardly backward is provided at the lower end of the front steel plate for fixing the specimen, and the loading mechanism comprises a steel hanging basket and a counterweight. A hanging rope is provided on the steel hanging basket, and the steel hanging basket is hooked in the steel groove of the front steel plate for fixing the specimen by the hanging rope, and the counterweight is placed on the steel hanging basket.

[0010] Furthermore, it also includes a buffer pad, which is installed at the upper end of the supporting base plate and is located directly below the rear steel plate for fixing the specimen, the front steel plate for fixing the specimen, the specimen and the loading mechanism.

[0011] Furthermore, the buffer pad is made of rubber, foam or sandwich composite material.

[0012] Furthermore, the front end of the specimen fixing rear steel plate is bonded to the specimen via a viscoelastic adhesive layer, and the front end of the specimen is bonded to the specimen fixing front steel plate via a viscoelastic adhesive layer.

[0013] Furthermore, the supporting base plate is made of reinforced concrete.

[0014] Furthermore, a lockable universal wheel is provided at the lower end of the supporting base plate.

[0015] Furthermore, it also includes embedded anchor rods. The supporting base plate is provided with embedded anchor rods. The lower end of the steel column is provided with a connecting plate. The steel column is connected to the supporting base plate through the connection between the connecting plate and the embedded anchor rods.

[0016] Furthermore, a stiffening rib is provided between the steel column and the connecting plate.

[0017] Furthermore, the counterweight block is a steel block or a concrete block.

[0018] The beneficial effects of the utility model are:

[0019] The utility model utilizes steel columns, steel beams, and a connection arrangement of a specimen fixing rear steel plate, a specimen fixing front steel plate, and a specimen installed at the front end of the steel beam to simulate a shear creep test environment of a composite sandwich layer, and adopts a loading mechanism to directly apply shear force on a test surface of the specimen, thereby solving the problem that shear creep test loading of the sandwich layer is difficult and shear creep performance data can only be obtained indirectly; and the arrangement of multiple specimen fixing rear steel plates, specimen fixing front steel plates, and loading mechanisms can be simultaneously utilized to test the shear creep performance of multiple specimens separately.

[0020] The utility model bonds the specimen with the rear steel plate for fixing the specimen, the front steel plate for fixing the specimen and the specimen through a viscoelastic adhesive layer, which can avoid damage to the specimen caused by rigid connections such as bolts and can effectively transfer shear stress. During the test, the shear stress is transferred to the test surface of the specimen through the viscoelastic adhesive layer used to bond the rear steel plate for fixing the specimen and the front steel plate for fixing the specimen to the specimen respectively, so as to effectively simulate the real shear stress condition of the sandwich layer of the composite sandwich structure when the composite sandwich structure is subjected to bending load. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an overall schematic diagram of a shear creep test loading device proposed by the utility model;

[0022] Figure 2 A supporting base plate of a shear creep test loading device proposed by the utility model;

[0023] Figure 3 A buffer pad of a shear creep test loading device proposed by the utility model;

[0024] Figure 4 A steel column of a shear creep test loading device proposed by the utility model;

[0025] Figure 5 A steel beam of a shear creep test loading device proposed by the utility model;

[0026] Figure 6 A steel plate is provided after the specimen is fixed to a shear creep test loading device proposed by the utility model;

[0027] Figure 7 It is a specimen fixing front steel plate of a shear creep test loading device proposed by the utility model;

[0028] Figure 8 A steel hanging basket of a shear creep test loading device proposed by the utility model;

[0029] Fig. 9 The utility model provides a pre-buried anchor rod of a shear creep test loading device.

[0030] Among them: 1—support base plate; 2—buffer pad; 3—steel column; 4—steel beam; 5—rear steel plate for specimen fixation; 6—front steel plate for specimen fixation; 7—steel hanging basket; 8—counterweight block; 9—embedded anchor rod; 10—test specimen. DETAILED DESCRIPTION

[0031] The utility model is described in detail below with reference to the accompanying drawings.

[0032] As attached Figure 1 As shown, a shear creep test loading device according to an embodiment of the utility model comprises a supporting base plate 1, a steel column 3, a steel beam 4, a specimen fixing rear steel plate 5, a specimen fixing front steel plate 6 and a loading mechanism. Two steel columns 3 are installed on the supporting base plate 1. The upper ends of the two steel columns 3 are connected by a steel beam 4. The front end surface of the steel beam 4 is fixedly connected with a Figure 6 The specimen is fixed with a rear steel plate 5 , the front end of which is connected to a specimen 10 , the front end of which is connected to a front steel plate 6 , and the front steel plate 6 is connected to a loading mechanism for applying shear force to the specimen 10 .

[0033] The utility model utilizes a steel column 3, a steel beam 4, and a connection arrangement of a specimen fixing rear steel plate 5, a specimen fixing front steel plate 6, and a specimen 10 installed at the front end of the steel beam 4 to simulate a shear creep test environment of a composite sandwich layer, and adopts a loading mechanism to directly apply a shear force on a test surface of the specimen 10, thereby solving the problem that shear creep test loading of the sandwich layer is difficult and shear creep performance data can only be obtained indirectly; and the arrangement of multiple specimen fixing rear steel plates 5, specimen fixing front steel plates 6, and loading mechanisms can be simultaneously utilized to test the shear creep performance of multiple specimens 10 separately.

[0034] In another specific embodiment, the front end of the specimen fixing rear steel plate 5 is bonded to the specimen 10 via a viscoelastic adhesive layer, and the front end of the specimen 10 is bonded to the specimen fixing front steel plate 6 via a viscoelastic adhesive layer.

[0035] In this scheme, the specimen fixing rear steel plate 5, the specimen fixing front steel plate 6 and the specimen 10 are bonded together by a viscoelastic adhesive layer, which can not only avoid damage to the specimen 10 caused by rigid connections such as bolts, but also effectively transfer the shear stress; during the test, the shear stress is transferred to the test surface of the specimen 10 through the viscoelastic adhesive layer used to bond the specimen fixing rear steel plate 5, the specimen fixing front steel plate 6 and the specimen 10 respectively, so as to effectively simulate the actual shear stress condition of the sandwich layer of the composite sandwich structure when it is subjected to bending load.

[0036] As attached Figure 7 and attached Figure 8As shown, in another specific embodiment, the lower end of the front steel plate 6 for fixing the specimen is provided with a steel groove that is buckled backward and inward, and the loading mechanism includes a steel hanging basket 7 and a counterweight 8. The steel hanging basket 7 is provided with a hanging rope, and the steel hanging basket 7 is hooked in the steel groove of the front steel plate 6 for fixing the specimen through the hanging rope, and the steel hanging basket 7 is used to place the counterweight 8. In this way, when in use, the steel hanging basket 7 can be hooked in the steel groove of the front steel plate 6 for fixing the specimen through the hanging rope, and a counterweight 8 of a preset weight can be placed on the steel hanging basket 7 as needed, wherein the counterweight 8 can be in the form of any material such as a steel block, a concrete block, etc., and the size of the counterweight 8 can be arbitrarily selected.

[0037] As attached Figure 3 As shown, in another specific embodiment, a buffer pad 2 is further included. The buffer pad 2 is installed at the upper end of the supporting base plate 1 and is located directly below the specimen fixing rear steel plate 5, the specimen fixing front steel plate 6, the specimen and the loading mechanism. The buffer pad 2 can be made of any material with buffering and energy absorption functions, such as rubber, foam or sandwich composite materials; the size of the buffer pad 2 should be sufficient to cover the entire falling area of ​​the steel hanging basket 7. In this solution, the buffer pad 2 is placed directly below the specimen fixing rear steel plate 5, the specimen fixing front steel plate 6, the specimen and the loading mechanism, which can prevent the specimen 10 from falling with the steel hanging basket 7 after being damaged, and directly hitting the supporting base plate 1, causing damage to the equipment.

[0038] In another specific embodiment, the support base plate 1 is made of reinforced concrete, thereby increasing the service rigidity of the support base plate 1, thereby increasing the service life of the device and facilitating manufacturing.

[0039] In another specific embodiment, a lockable universal wheel is provided at the lower end of the supporting base plate 1, so as to facilitate the movement and positioning of the entire device as required.

[0040] As attached Figure 2 and attached Fig. 9 As shown, in another specific embodiment, it further includes embedded anchor rods 9, the supporting base plate 1 is provided with embedded anchor rods 9, the lower end of the steel column 3 is provided with a connecting plate, and the steel column 3 is connected to the supporting base plate 1 through the connection between the connecting plate and the embedded anchor rods 9. In this way, the steel column 3 is easily installed stably.

[0041] As attached Figure 4 As shown, a stiffening rib is provided between the steel column 3 and the connecting plate, thereby further increasing the stability of the steel column 3 when in use.

[0042] When the device of the utility model is used, the length of the steel beam 4 is determined according to the number of test pieces 10 to be loaded simultaneously, and based on this, the size of the support base plate 1 is further determined. According to the size of the support base plate 1, the formwork is supported, the steel bars are arranged, and the embedded anchor rods 9 are welded to the arranged steel bars; concrete is poured, and after curing for 28 days under standard curing conditions, the support base plate 1 made of reinforced concrete is obtained, and the steel columns 3 are fixed by bolting at the embedded anchor rods 9, and the steel beam 4 and the steel columns 3 are connected by welding or bolting.

[0043] Afterwards, the specimen fixing rear steel plate 5 is fixed to the steel beam 4 by bolt connection, and the specimen 10 is fixed between the specimen fixing rear steel plate 5 and the specimen fixing front steel plate 6 by bonding through a viscoelastic adhesive layer. The counterweight 8 is stacked on the steel hanging basket 7, and the steel hanging basket 7 is suspended in the steel groove below the specimen fixing front steel plate 6 to apply shear force to the specimen 10. A buffer pad 2 is placed under the steel hanging basket 7 to prevent the steel hanging basket 7 from falling after the specimen 10 is damaged and directly hitting the supporting bottom plate 1.

[0044] The utility model device applies shear force directly on the test surface of the test piece 10 through the steel hanging basket 7, and the magnitude of the shear force can be freely adjusted through the counterweight block 8. The utility model device can simultaneously perform shear creep performance tests on multiple test pieces 10 by adjusting the use length of the steel beam 4 and the number of the test piece fixing rear steel plates 5 fixed on the steel beam 4. Among them, the cross-sectional form of the steel column 3 can adopt any suitable cross-sectional form such as hot-rolled steel section, solid web composite section, lattice composite section, etc. Figure 5 As shown, the steel beam 4 can be in the form of a channel steel beam, a composite beam, or any other form that meets the force requirements and is convenient for connection with the steel column 3. The buffer block 2 can be in the form of any material that has a buffering and energy-absorbing function, such as rubber, foam, or sandwich composite materials; the size of the buffer block 2 should be sufficient to cover the entire falling area of ​​the steel hanging basket. The counterweight block 8 can be in the form of any material, such as a steel block, a concrete block, or any other form; the size of the counterweight block can be selected arbitrarily.

[0045] During the above-mentioned construction and assembly process: the size of the supporting base plate 1 of the device, the type of steel bars, the concrete strength grade, the position, quantity and size of the embedded anchor rods 9; the size of each component of the steel structure body, the type and connection method of steel, the position, quantity and size of the reserved bolt holes; and the size and material composition of the buffer pad 2 can all be flexibly adjusted as needed.

[0046] The operation method of this device is as follows:

[0047] (1) Fixing of the test piece 10

[0048] The size of the specimen 10 should be determined according to the available range between the bolt holes on the steel plate 5 after the specimen is fixed. The fixing operation of the specimen 10 is as follows: first, the steel plate 6 before the specimen is fixed is placed flat on the operating table with the steel groove facing upward, and the structural adhesive is applied on the surface of the steel plate 6 before the specimen is fixed to form a viscoelastic adhesive layer, and the specimen 10 is placed on the steel plate 6 before the specimen is fixed, with the test surface of the specimen 10 facing downward and in full contact with the viscoelastic adhesive layer on the surface of the steel plate 6 before the specimen is fixed. Then, the structural adhesive is applied on the side of the steel plate 5 after the specimen is fixed that should contact the specimen 10 to also form a viscoelastic adhesive layer, and pressed on the top of the specimen 10. Finally, a certain weight of steel blocks are evenly stacked on the steel plate 5 after the specimen is fixed for 48 hours of pressure holding treatment. Another purpose of stacking steel blocks on the steel plate 5 after the specimen is fixed is to squeeze out excess structural adhesive, so that the thickness of the viscoelastic adhesive layer is as thin as possible, so as to minimize the influence of the viscoelastic adhesive layer on the shear creep performance of the specimen.

[0049] (2) Calculate the mass of the required counterweight 8

[0050] The dimensions of the rectangular test piece 10 in two directions are recorded as a and b respectively, and the shear stress required to be applied on the test piece 10 is recorded as τ. Then the total weight of the weight required to be suspended below the test piece 10 is abτ. Use an electronic weighing scale to weigh the mass m of the steel hanging basket 7. 1 , then the mass of the counterweight block 8 required is m 2 for:

[0051]

[0052] Where: g is the local gravitational acceleration.

[0053] (3) Loading

[0054] The specimen fixing front steel plate 6, the specimen 10 and the specimen fixing rear steel plate 5 bonded together by the viscoelastic adhesive layer are fixed to the steel beam 4 by bolting the specimen fixing rear steel plate 5, and the buffer pad 2 is placed under the specimen 10. The calculated mass m 2 The counterweight 8 is placed on the steel hanging basket 7, and the steel hanging basket 7 and the counterweight 8 are lifted together and hung in the steel groove below the front steel plate 6 of the specimen, so that the required shear force is instantly applied to the specimen 10. The deformation on the test surface of the specimen 10 is measured with a dial indicator to directly obtain the corresponding raw data of the shear creep test.

[0055] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "back", etc. used in the utility model are only for the convenience of description and are not used to limit the scope of implementation of the utility model. Changes or adjustments in their relative relationships should be regarded as the scope of implementation of the utility model without substantially changing the technical content.

[0056] The above are only preferred implementations of the utility model. The protection scope of the utility model is not limited to the above embodiments. All technical solutions under the idea of ​​the utility model belong to the protection scope of the utility model. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the utility model should be regarded as the protection scope of the utility model.

Claims

1. A shear creep test loading device, characterized in that: The invention comprises a supporting base plate (1), a steel column (3), a steel beam (4), a specimen fixing rear steel plate (5), a specimen fixing front steel plate (6) and a loading mechanism, wherein two steel columns (3) are mounted on the supporting base plate (1), the upper ends of the two steel columns (3) are connected via a steel beam (4), the specimen fixing rear steel plate (5) is fixedly connected to the front end surface of the steel beam (4), the specimen fixing rear steel plate (5) is connected to the front end of the specimen fixing rear steel plate (5), the specimen (10) is connected to the front end of the specimen (10) is connected to the specimen fixing front steel plate (6), the specimen fixing front steel plate (6) is connected to the loading mechanism, and the loading mechanism is used to apply a shear force to the specimen (10).

2. A shear creep test loading device according to claim 1, characterized in that: The lower end of the specimen fixing front steel plate (6) is provided with a steel groove that is turned inwards backwards, and the loading mechanism comprises a steel hanging basket (7) and a counterweight (8). The steel hanging basket (7) is provided with a hanging rope, and the steel hanging basket (7) is hooked in the steel groove of the specimen fixing front steel plate (6) by the hanging rope. The counterweight (8) is placed on the steel hanging basket (7).

3. A shear creep test loading device according to claim 1, characterized in that: It also comprises a buffer pad (2), which is mounted on the upper end of the supporting base plate (1) and is located directly below the specimen fixing rear steel plate (5), the specimen fixing front steel plate (6), the specimen (10) and the loading mechanism.

4. A shear creep test loading device according to claim 3, characterized in that: The buffer pad (2) is made of rubber, foam or sandwich composite material.

5. A shear creep test loading device according to claim 1, characterized in that: The front end of the specimen fixing rear steel plate (5) is bonded to the specimen (10) via a viscoelastic adhesive layer, and the front end of the specimen (10) is bonded to the specimen fixing front steel plate (6) via a viscoelastic adhesive layer.

6. A shear creep test loading device according to claim 1, characterized in that: The supporting base plate (1) is made of reinforced concrete.

7. A shear creep test loading device according to claim 1, characterized in that: The lower end of the supporting base plate (1) is provided with a lockable universal wheel.

8. A shear creep test loading device according to claim 1, characterized in that: It also includes embedded anchor rods (9), the supporting base plate (1) is provided with embedded anchor rods (9), the lower end of the steel column (3) is provided with a connecting plate, and the steel column (3) is connected to the supporting base plate (1) through the connection between the connecting plate and the embedded anchor rods (9).

9. A shear creep test loading device according to claim 8, characterized in that: A stiffening rib plate is provided between the steel column (3) and the connecting plate.

10. A shear creep test loading device according to claim 2, characterized in that: The counterweight block (8) is a steel block or a concrete block.

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