Multi-degree-of-freedom dynamic boundary coordination loading device

Abstract

The invention discloses a multi-degree-of-freedom dynamic boundary coordination loading device which comprises a frame, the frame comprises two supports, a plurality of upper cross beams and a plurality of lower cross beams are detachably connected between the two supports, each support comprises two stand columns, a plurality of connecting rods are fixedly connected between the two stand columns, and a plurality of bolt holes are formed in the stand columns. The two ends of the upper cross beam and the two ends of the lower cross beam are detachably arranged in the bolt holes through bolts, supporting rods are fixedly connected between the upper cross beam and the stand columns through bolts, the upper cross beam and the lower cross beam are fixedly connected with bottom plates, the bottom plates are fixedly connected with two linear guide rails, the linear guide rails are slidably connected with sliding blocks, and the sliding blocks are fixedly connected with a table top. A mass block is fixedly connected to the table top, a linear motor is arranged between the table top and the bottom plate, and a three-way force sensor is fixedly connected to the bottom end of the stand column.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering test devices, in particular to a multi-degree-of-freedom dynamic boundary coordinated loading device. Background Art

[0002] With the rapid development of the global economy, large and complex structures emerge in an endless stream. However, once an earthquake strikes, the damage and collapse of engineering structures will cause large-scale economic losses and pose a great threat to the safety of people's lives. Therefore, before the engineering structure is applied to a specific actual project, it is necessary to conduct an earthquake resistance evaluation to meet people's requirements for economy, safety, and applicability.

[0003] When faced with large-scale, over-limit, lifeline and other major safety projects or nonlinear structural research, seismic model tests are still an indispensable research method for evaluating the seismic performance of structures and the basis for measuring the accuracy of numerical simulation analysis. Due to the randomness of earthquakes and the complexity of structural seismic performance, traditional seismic model tests cannot truly restore the actual stress state of structures or components and cannot accurately simulate real complex dynamic boundary loading conditions.

[0004] Therefore, a multi-degree-of-freedom dynamic boundary coordinated loading device is proposed to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a multi-degree-of-freedom dynamic boundary coordinated loading device to solve the problems existing in the above-mentioned prior art, aiming to simulate a more realistic and complex stress state of the structure, further reveal the destruction mechanism of the engineering structure under the action of earthquake, and realize a more realistic and accurate test evaluation of the lower substructure.

[0006] To achieve the above object, the present invention provides the following solution: The present invention provides a multi-degree-of-freedom dynamic boundary coordinated loading device, comprising:

[0007] The frame comprises two brackets, a plurality of upper beams and a plurality of lower beams are detachably connected between the two brackets, the bracket comprises two columns, a plurality of connecting rods are fixedly connected between the two columns, a plurality of bolt holes are provided on the columns, both ends of the upper beam and the lower beam are detachably inserted into the bolt holes by bolts, a support rod is fixedly connected between the upper beam and the columns by the bolts, a base plate is fixedly connected to the upper beam and the lower beam, two linear guide rails are fixedly connected to the base plate, a slider is slidably connected to the linear guide rails, a table is fixedly connected to the slider, a mass block is fixedly connected to the table, a linear motor is arranged between the table and the base plate, and a three-axis force sensor is fixedly connected to the bottom end of the column.

[0008] The present invention discloses the following technical effects: BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0010] Figure 1 It is a schematic diagram of the structure of the multi-degree-of-freedom dynamic boundary coordinated loading device of the present invention;

[0011] Figure 2 It is a schematic diagram of the method of using the present invention;

[0012] Among them, 1. frame; 2. bracket; 3. three-axis force sensor; 4. upper beam; 5. lower beam; 6. column; 7. connecting rod; 8. bolt hole; 9. support rod; 10. bottom plate; 11. linear guide; 12. slider; 13. table; 14. mass block; 15. linear motor. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Reference Figure 1-2 The present invention provides a multi-degree-of-freedom dynamic boundary coordinated loading device, comprising:

[0016] Frame 1, frame 1 includes two brackets 2, a plurality of upper beams 4 and a plurality of lower beams 5 are detachably connected between the two brackets 2, the bracket 2 includes two columns 6, a plurality of connecting rods 7 are fixedly connected between the two columns 6, a plurality of bolt holes 8 are opened on the column 6, both ends of the upper beam 4 and the lower beam 5 are detachably connected in the bolt holes 8 by bolts, a support rod 9 is fixedly connected between the upper beam 4 and the column 6 by bolts, a base plate 10 is fixedly connected to the upper beam 4 and the lower beam 5, two linear guide rails 11 are fixedly connected to the base plate 10, a slider 12 is slidably connected to the linear guide rail 11, a table 13 is fixedly connected to the slider 12, a mass block 14 is fixedly connected to the table 13, a linear motor 15 is arranged between the table 13 and the base plate 10, and a three-axis force sensor 3 is fixedly connected to the bottom end of the column 6.

[0017] The linear motor comprises an electromagnetic coil and a permanent magnet stator. The permanent magnet stator is fixedly connected to the bottom plate, and the electromagnetic coil is fixedly connected to the table top.

[0018] A method for using a multi-degree-of-freedom dynamic boundary coordinated loading device comprises the following steps:

[0019] Step 1: A 6-story RC frame 1 structure is selected as the research object, the lower three floors of frame 1 are the physical substructure, and the theoretical model is derived based on structural dynamics;

[0020] Step 2, measuring the absolute acceleration of the physical substructure by an acceleration sensor;

[0021] Step 3, as input, the shear force and bending moment of the boundary conditions are back-calculated based on the ideal dynamic model;

[0022] Step 4, changing the height of the slider 12 in the multi-degree-of-freedom dynamic boundary coordinated loading device to obtain a combination of shear force and bending moment;

[0023] Step five, sending corresponding driving commands through the multi-degree-of-freedom dynamic boundary coordinated loading device, and finally realizing the multi-degree-of-freedom dynamic boundary loading of the six-layer frame 1.

[0024] According to a further optimization scheme, the frame 1 is a rigid body, the frame 1 has four columns and supports, and each column has bolt holes with equal spacing.

[0025] In a further optimized solution, the mass block 14 is driven by a linear motor 15 to avoid the influence of heavy hydraulic pipes on boundary loading.

[0026] In a further optimized solution, the mass block 14 operates in a displacement control mode and is limited by the current amplifier, thereby improving the safety of the device.

[0027] To further optimize the solution, the three-axis force sensor 3 is used to measure and estimate the shear and bending moment output values ​​to improve the loading accuracy of the device.

[0028] In a further optimized solution, the slider 12 is supported by two linear guide rails 11 , and the mass block 14 can move relative to the frame 1 through the slider 12 .

[0029] In the hybrid experiment, in order to realize the multi-degree-of-freedom dynamic boundary loading of the three-layer experimental substructure under a six-layer frame 1, a multi-degree-of-freedom dynamic boundary coordinated loading device is used. The frame 1 is rigid to avoid the reduction of loading accuracy due to its own deformation. It is composed of four steel columns and supports. As a load-bearing component, it is used to fix the bracket 2, three-axis force sensor 3, upper beam 4, lower beam 5, column 6, connecting rod 7, bolt hole 8, support rod 9, bottom plate 10, linear guide 11, slider 12, table 13, mass block 14, linear motor 15. Each column 6 has bolt holes 8 with equal spacing. Therefore, different combinations of shear force and bending moment can be flexibly obtained by changing the height of the mass block 14. Each mass block 14 is driven by a linear motor 15, which can avoid the influence of heavy hydraulic pipes on boundary loading. The linear motor 15 is composed of an electromagnetic coil and a permanent magnet stator. The electromagnetic coil is connected to the table 13 and is used to drive the mass block 14, while the permanent magnet stator is fixed on the frame 1. The slider 12 is supported by two linear guides 11. The mass block 14 can move relative to the frame 1 through the slider 12. The linear motor 15 is driven by the current controller, but the mass block 14 operates in displacement control mode and is limited by the current amplifier. A three-axis force sensor 3 is installed between the boundary coordination device and the test body to measure and estimate the shear and bending moments and improve the accuracy of the device.

[0030] First, the overall structural dynamic model 16 of the six-story frame 1 is calculated to derive the idealized structural dynamic model 17. The vibration table is loaded and the absolute acceleration of the physical substructure 18 (the three-story frame 1 below) is measured using an acceleration sensor. This is used as input and the ideal dynamic model established previously is used to inversely calculate the shear force and bending moment of the boundary through the finite element model 19 (test substructure). The corresponding drive command is sent through the multi-degree-of-freedom dynamic boundary coordinated loading device to finally achieve multi-degree-of-freedom dynamic boundary loading of the six-story frame 1. The above is a typical implementation case of the present invention, and the implementation of the present invention is not limited to this.

[0031] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0032] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A multi-degree-of-freedom dynamic boundary coordinated loading device, characterized in that: include: A frame (1), wherein the frame (1) comprises two brackets (2), wherein a plurality of upper cross beams (4) and a plurality of lower cross beams (5) are detachably connected between the two brackets (2), wherein the bracket (2) comprises two upright posts (6), wherein a plurality of connecting rods (7) are fixedly connected between the two upright posts (6), wherein the upright posts (6) are provided with a plurality of bolt holes (8), wherein both ends of the upper cross beam (4) and the lower cross beam (5) are detachably fixed in the bolt holes (8) by bolts, and wherein the upper cross beam (4) and the upright posts (6) are fixedly fixed by the bolts. A support rod (9) is connected, the upper crossbeam (4) and the lower crossbeam (5) are both fixedly connected to a base plate (10), the base plate (10) is fixedly connected to two linear guide rails (11), the linear guide rails (11) are slidably connected to a slider (12), a table (13) is fixedly connected to the slider (12), a mass block (14) is fixedly connected to the table (13), a linear motor (15) is arranged between the table (13) and the base plate (10), and a three-axis force sensor (3) is fixedly connected to the bottom end of the column (6).

2. A method for using a multi-degree-of-freedom dynamic boundary coordinated loading device, based on the multi-degree-of-freedom dynamic boundary coordinated loading device according to claim 1, characterized in that: The steps include: Step 1: A 6-story RC frame (1) structure is selected as the research object, the lower three layers of the frame (1) are the physical substructure, and the theoretical model is derived based on structural dynamics; Step 2, measuring the absolute acceleration of the physical substructure by an acceleration sensor; Step 3, as input, the shear force and bending moment of the boundary conditions are back-calculated based on the ideal dynamic model; Step 4, changing the height of the slider (12) in the multi-degree-of-freedom dynamic boundary coordinated loading device to obtain a combination of shear force and bending moment; Step 5: Send corresponding drive commands through the multi-degree-of-freedom dynamic boundary coordinated loading device, and finally realize the multi-degree-of-freedom dynamic boundary loading of the six-layer frame (1).

3. A multi-degree-of-freedom dynamic boundary coordinated loading device according to claim 1, characterized in that: The frame (1) is a rigid body, and has four columns and supports, and each column has bolt holes at equal intervals.

4. A multi-degree-of-freedom dynamic boundary coordinated loading device according to claim 1, characterized in that: The mass block (14) is driven by the linear motor (15) to avoid the influence of heavy hydraulic pipes on boundary loading.

5. The multi-degree-of-freedom dynamic boundary coordinated loading device according to claim 1, characterized in that: The mass block (14) operates in a displacement control mode and is limited by a current amplifier, thereby improving the safety of the device.

6. A multi-degree-of-freedom dynamic boundary coordinated loading device according to claim 1, characterized in that: The three-axis force sensor (3) is used to measure and estimate shear and bending moment output values, thereby improving the loading accuracy of the device.

7. The multi-degree-of-freedom dynamic boundary coordinated loading device according to claim 1, characterized in that: The slider (12) is supported by the two linear guide rails (11), and the mass block (14) can move relative to the frame (1) through the slider (12).

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