A device for testing the hysteresis of the axis of a rod

Abstract

The utility model discloses a civil engineering field is a kind of pole piece axial hysteresis loading test device. Including counterforce frame, steel beam limiting assembly is equipped on counterforce frame, and there is square mouth in steel beam limiting assembly, and the inner wall surface of square mouth is equipped with a plurality of universal ball, and universal ball is fixed on steel beam limiting assembly, square rigid positioning block is slidably inserted in square mouth, MTS actuator is equipped on the lower bottom surface of counterforce beam, and the lower end of MTS actuator is fixed on the top surface of square rigid positioning block, and first one-way hinge base is connected on the bottom surface of square rigid positioning block, and pole piece is hinged on first one-way hinge base, and second one-way hinge base is hinged on the lower end of pole piece, and MTS actuator, square rigid positioning block and pole piece are all same axial center. Optimize the three major defects of "load eccentric, constraint condition mismatch, friction interference" in prior art, realize repeatedly exerting axial tension and compression load to pole piece, so that axial loading precision, condition adhesion degree, loading stability are significantly improved.

Description

Technical Field

[0001] This utility model relates to the field of civil engineering technology, specifically a test device for axial hysteretic loading of rods. Background Technology

[0002] In the field of civil engineering, the axial tension-compression hysteresis performance of members is a key indicator for evaluating their seismic resistance and fatigue resistance. Therefore, it is necessary to simulate the actual load cycle through axial tension-compression hysteresis experiments to obtain core parameters such as the hysteresis curve, stiffness degradation, and energy dissipation capacity of the members.

[0003] Existing loading systems typically use a "reaction frame + vertical actuator" as their core, but they still have some technical shortcomings and cannot meet the requirements of high-quality experiments. The specific problems are as follows: 1. Loads are prone to deviating from the axis of the member, leading to distorted experimental data. The existing MTS system directly applies loads to the member, which is very prone to slight horizontal offsets during the loading process, directly causing the vertical load to deviate from the axis of the member. Load eccentricity introduces additional bending moments, causing the member to bear not only tensile and compressive loads but also bending forces, which contradicts the requirements of the "axial hysteresis test". Ultimately, the measured hysteresis curves, bearing capacity and other data cannot truly reflect the axial mechanical properties of the member. 2. The constraints cannot meet the actual working conditions of "rotation in a single plane". In actual engineering, most hinged members only rotate in a specific single plane, rather than rotating freely in multiple planes. However, the connection structure design of the existing loading system has defects: either it adopts "fixed end connection" to restrict the rotation of the member in all directions, which cannot simulate the actual hinged working conditions, or it allows the member to rotate arbitrarily in three-dimensional space, which exceeds the actual engineering scenario of "rotation in a single plane". 3. High friction between the constraint structure and the loading component affects loading accuracy. In existing systems, the constraint structure used to limit horizontal displacement, such as the positioning plate and the fixed frame, is mostly in "rigid sliding contact" without friction reduction measures, resulting in high load loss and poor accuracy. Utility Model Content

[0004] This invention aims to solve the above-mentioned problems and provides a rod axial hysteresis loading test device. This invention optimizes the three major technical defects in the prior art: "load eccentricity, constraint mismatch, and friction interference". It enables repeated application of axial tensile and compressive loads to rods hinged to the first and second one-way hinge seats, simulating the tension and compression of rods in actual engineering. It can better meet the requirements of rod axial hysteresis loading test and has significant technical improvements in three dimensions: axial loading accuracy, working condition fit, and loading stability, ensuring experimental accuracy and stability.

[0005] The technical solution adopted by this utility model to solve the aforementioned problem is: A rod axial hysteresis loading test device, set on a test bench, includes a reaction frame set on the test bench, a steel beam limiting assembly set in the middle of the reaction frame, a vertically penetrating square opening reserved in the middle of the steel beam limiting assembly, several universal balls set on the four inner walls of the square opening, and the universal balls being fixed to the steel beam limiting assembly accordingly. A square rigid positioning block is slidably inserted into the square opening, and the universal balls are clamped between the square rigid positioning block and the steel beam limiting assembly. The test includes a reaction beam, on the bottom surface of which is mounted an MTS actuator that loads vertically. The lower end of the MTS actuator is fixed to the top surface of a square rigid positioning block. A first one-way hinge is connected to the bottom surface of the square rigid positioning block. A rod is hinged to the first one-way hinge, and a second one-way hinge is hinged to the lower end of the rod. The second one-way hinge and the first one-way hinge are symmetrical, and the second one-way hinge is fixed on the test bench. The MTS actuator, the square rigid positioning block, and the rod are all on the same axis.

[0006] As a preferred embodiment, a further technical solution of this utility model is as follows: Preferably, the reaction frame also includes two identical and symmetrically arranged portal frames, with the reaction beam horizontally arranged and fixed to the upper part of the two portal frames.

[0007] Preferably, the steel beam limiting assembly includes two long steel beams, one of which is fixed on the same side of the two portal brackets, and the other is fixed on the other side of the two portal brackets. Both long steel beams are parallel to the reaction beam. Two short steel beams are fixedly connected between the two long steel beams. The two short steel beams are symmetrical about the square rigid positioning block. Limiting steel beams are vertically fixed on the inner surfaces of the two long steel beams and the inner surfaces of the two short steel beams. The four limiting steel beams have the same length and correspond one-to-one with the four sides of the square rigid positioning block. Several universal balls are fixed to the ends of the four limiting steel beams near the square rigid positioning block.

[0008] Preferably, several omnidirectional balls are arranged in a rectangular array at the ends of the limiting steel beam.

[0009] Preferably, the omnidirectional ball includes a ball support fixed to the end of the limiting steel beam, and a rolling ball that is in contact with the square rigid positioning block is rolled on the ball support.

[0010] Preferably, the square rigid positioning block is cuboid in shape, and the height of the square rigid positioning block varies with the estimated deformation.

[0011] Preferably, the MTS actuator includes a body fixedly connected to the reaction beam, and a loading end that reciprocates in the vertical direction is installed on the body. The lower end of the loading end is fixed to the top surface of the square rigid positioning block.

[0012] Compared with the prior art, the outstanding features of this utility model, which adopts the above technical solution, are: This invention addresses three major technical shortcomings in existing technologies: load eccentricity, mismatched constraint conditions, and frictional interference. It utilizes a reaction frame, MTS actuator, steel beam limiting assembly, square rigid positioning block, universal ball, first one-way hinge seat, and second one-way hinge seat to repeatedly apply axial tensile and compressive loads to members hinged to the first and second one-way hinge seats. This simulates the tension and compression conditions of hinged members in actual engineering projects, effectively fulfilling the requirements of axial hysteretic loading tests. It significantly improves axial loading accuracy, condition fit, and loading stability, ensuring experimental accuracy and stability. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the main view structure of this utility model; Figure 2 yes Figure 1 A schematic diagram of a partially enlarged structure; Figure 3 This is a schematic diagram of the side view structure of this utility model; Figure 4 This is a schematic diagram of the top view of the structure of this utility model; Figure 5 This is a schematic diagram of the structure of the universal ball of this utility model; In the diagram: 1. Reaction frame; 2. Reaction beam; 3. Portal bracket; 4. Steel beam limiting assembly; 5. Long steel beam; 6. Short steel beam; 7. Limiting steel beam; 8. Universal ball; 9. Ball bearing; 10. Rolling ball; 11. Square rigid positioning block; 12. MTS actuator; 13. First one-way hinge; 14. Second one-way hinge; 15. Rod. Detailed Implementation

[0014] The following description of the embodiments will help the public better understand the present invention. However, the specific embodiments provided by the applicant should not and should not be regarded as a limitation on the technical solution of the present invention. Any changes to the definition of components or technical features and / or formal but not substantive changes to the overall structure should be regarded as the scope of protection defined by the technical solution of the present invention.

[0015] See Figures 1 to 5 As shown, the technical solution of this utility model is as follows: A rod axial hysteresis loading test device is set on a test bench and includes a reaction frame 1. The reaction frame 1 is installed on the test bench and includes a reaction beam 2 and two portal brackets 3 with the same structure and arranged symmetrically from left to right. The reaction beam 2 is arranged horizontally and fixed to the upper part of the two portal brackets 3. The two portal brackets 3 are connected together through the reaction beam 2. A steel beam limiting component 4 is fixed in the middle of the reaction frame 1. The steel beam limiting component 4 includes two long steel beams 5. One long steel beam 5 is fixed on the same side of the two portal brackets 3, and the other long steel beam 5 is fixed on the other side of the two portal brackets 3. Both long steel beams 5 are parallel to the reaction beam 2. Two short steel beams 6 are fixedly connected between the two long steel beams 5. The two short steel beams 6 are symmetrical about the square rigid positioning block 11. Limiting steel beams 7 are vertically fixed on the inner sides of the two long steel beams 5 and the inner sides of the two short steel beams 6. The four limiting steel beams 7 have the same length and correspond one-to-one with the four sides of the square rigid positioning block 11. Furthermore, the ends of the four limiting steel beams 7 together form a square opening, through which the steel beam limiting component 4 passes vertically. Twelve universal balls 8 are installed on each of the four inner walls of the square opening. These twelve universal balls 8 are arranged in a rectangular array and fixed to the ends of each limiting steel beam 7 near the square rigid positioning block 11. The square rigid positioning block 11 is slidably inserted into the square opening. The universal balls 8 are sandwiched between the square rigid positioning block 11 and the steel beam limiting component 4. Each universal ball 8 includes a ball support 9 and a rolling ball 10. The ball support 9 is fixed to the end of the limiting steel beam 7, and the rolling ball 10 is rotatably mounted on the ball support 9. 0 is in contact with the square rigid positioning block 11. An MTS actuator 12 loaded in the vertical direction is installed on the bottom surface of the reaction beam 2. The lower end of the MTS actuator 12 is fixed to the top surface of the square rigid positioning block 11. A first one-way hinge seat 13 is connected to the bottom surface of the square rigid positioning block 11. A rod 15 is hinged to the first one-way hinge seat 13. A second one-way hinge seat 14 is hinged to the lower end of the rod 15. The second one-way hinge seat 14 and the first one-way hinge seat 13 are symmetrical. The second one-way hinge seat 14 is fixed on the test bench. The MTS actuator 12, the square rigid positioning block 11 and the rod 15 are all on the same axis.

[0016] The square rigid positioning block 11 is rectangular, and its height varies with the estimated deformation.

[0017] The MTS actuator 12 includes a body fixedly connected to the reaction beam 2, and a loading end that reciprocates in the vertical direction is installed on the body. The lower end of the loading end is fixed to the top surface of the square rigid positioning block 11.

[0018] Operating principle: An MTS actuator 12, which loads vertically, is mounted on the reaction frame 1. The MTS actuator 12 only generates vertical loads and acts on the square rigid positioning block 11. The four sides of the square rigid positioning block 11 are fixed by limiting steel beams 7 to prevent horizontal displacement, thus loading is only performed in the vertical direction. A universal ball 8 is sandwiched between the four limiting steel beams 7 and the square rigid positioning block 11, thereby reducing the vertical displacement between the limiting steel beams 7 and the square rigid positioning block 11 through the universal ball 8. The frictional force generated by directional displacement is used to fix the bottom surface of the square rigid positioning block 11 to the first one-way hinge seat 13 and the rod 15, and the lower end of the rod 15 is hinged to the second one-way hinge seat 14. The first one-way hinge seat 13 and the second one-way hinge seat 14 are symmetrical, so that the rod 15 rotates in a single plane during the test and the load is not eccentric. When working, axial tensile and compressive loads are repeatedly applied to the rod 15 to simulate the tension and compression of the hinged rod 15 in actual engineering, which can better meet the requirements of the axial hysteretic loading test of the rod 15.

[0019] The beneficial technical effects of this utility model are: it optimizes the three major technical defects in the existing technology of "load eccentricity, constraint condition mismatch, and friction interference", and then, through the joint cooperation of the reaction frame 1, MTS actuator 12, steel beam limiting component 4, square rigid positioning block 11, universal ball 8, first one-way hinge seat 13 and second one-way hinge seat 14, it can repeatedly apply axial tensile and compressive loads to the rod 15 hinged to the first one-way hinge seat 13 and the second one-way hinge seat 14, simulate the tension and compression situation of the rod 15 hinged in actual engineering, and can better meet the requirements of the axial hysteretic loading test of the rod 15. It produces significant technical improvements in three dimensions: axial loading accuracy, working condition fit, and loading stability, ensuring experimental accuracy and stability.

[0020] The above description is only a preferred embodiment of the present utility model and does not limit the scope of the present utility model. All equivalent changes made based on the content of the present utility model specification and its drawings are included within the scope of the present utility model.

Claims

1. A test apparatus for axial hysteresis loading of a rod, set on a test bench, characterized in that: The test includes a reaction frame mounted on a test bench. A steel beam limiting assembly is located in the middle of the reaction frame. A vertically extending square opening is pre-drilled in the middle of the steel beam limiting assembly. Several universal balls are installed on the four inner walls of the square opening, and each universal ball is correspondingly fixed to the steel beam limiting assembly. A square rigid positioning block is slidably inserted into the square opening. The universal balls are clamped between the square rigid positioning block and the steel beam limiting assembly. The reaction frame includes a reaction beam. An MTS actuator with vertical loading is mounted on the bottom surface. The lower end of the MTS actuator is fixed to the top surface of the square rigid positioning block. A first one-way hinge is connected to the bottom surface of the square rigid positioning block. A rod is hinged to the first one-way hinge. A second one-way hinge is hinged to the lower end of the rod. The second one-way hinge and the first one-way hinge are symmetrical. The second one-way hinge is fixed on the test bench. The MTS actuator, the square rigid positioning block and the rod are all on the same axis.

2. The rod axial hysteresis loading test device according to claim 1, characterized in that: The reaction frame also includes two identical and symmetrically arranged portal frames, with the reaction beam horizontally positioned and fixed to the upper part of the two portal frames.

3. The rod axial hysteresis loading test device according to claim 1, characterized in that: The steel beam limiting assembly includes two long steel beams. One long steel beam is fixed on the same side of the two portal brackets, and the other long steel beam is fixed on the other side of the two portal brackets. Both long steel beams are parallel to the reaction beam. Two short steel beams are fixedly connected between the two long steel beams. The two short steel beams are symmetrical about the square rigid positioning block. Limiting steel beams are vertically fixed on the inner surfaces of the two long steel beams and the inner surfaces of the two short steel beams. The four limiting steel beams are of the same length and correspond one-to-one with the four sides of the square rigid positioning block. Several universal balls are fixed to the ends of the four limiting steel beams near the square rigid positioning block.

4. The rod axial hysteresis loading test device according to claim 3, characterized in that: Several omnidirectional balls are arranged in a rectangular array at the end of the limiting steel beam.

5. The rod axial hysteresis loading test device according to claim 4, characterized in that: The omnidirectional ball includes a ball support fixed to the end of a limiting steel beam, and a rolling ball that is in contact with a square rigid positioning block is rolled on the ball support.

6. The rod axial hysteresis loading test device according to claim 1, characterized in that: The square rigid positioning block is rectangular in shape, and its height varies with the estimated deformation.

7. The axial hysteresis loading test device for rods according to claim 1, characterized in that: The MTS actuator includes a body fixedly connected to the reaction beam, and a loading end that reciprocates in the vertical direction is installed on the body. The lower end of the loading end is fixed to the top surface of the square rigid positioning block.

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