Zero-damping magnetic suspension wind tunnel segment model test device

Abstract

The invention discloses a zero-damping magnetic suspension wind tunnel segment model test device, and relates to the technical field of bridge wind resistance experiments, the zero-damping magnetic suspension wind tunnel segment model test device comprises a segment model, a laser displacement meter, an adjusting device and a guide rail device, the adjusting device comprises a damping adjusting device and a magnetic suspension adjusting device, the damping adjusting device is connected with four corners of the segment model, the magnetic suspension adjusting device is arranged below the segment model, the damping adjusting device is connected with the guide rail device in a clamping manner, and the guide rail device is fixed on a top plate and a bottom plate of a wind tunnel laboratory. Magnetic suspension replaces traditional spring suspension, zero-damping suspension of the segment model in a wind tunnel test is achieved, and therefore dampers can be flexibly arranged according to test requirements, and the test damping ratio can be adjusted in a stepless mode; in addition, according to the testing device, the section proportion of the supporting device is greatly reduced, interference to airflow is smaller, and the quality of an obtained wind field is better.

Description

Technical Field

[0001] The invention relates to the technical field of bridge wind resistance experiments, and in particular to a zero-damping magnetic suspension wind tunnel segment model test device. Background Art

[0002] As modern bridges evolve toward longer spans and lighter weight, wind resistance becomes a core design challenge. Wind tunnel testing, a key method for verifying bridge aerodynamic stability, is becoming increasingly relevant to bridge construction. Wind-induced vibrations, such as flutter and vortex vibrations, of long-span bridges directly impact their safety and service life. Therefore, wind tunnel testing, by simulating real-world wind conditions, provides an indispensable basis for optimizing bridge aerodynamic shapes and designing structural damping parameters.

[0003] At present, the suspension device for bridge wind-resistant segment model tests mainly relies on a combination of a spring suspension system and a mechanical damper. This device has the following significant disadvantages: the test device occupies a large cross-section of the wind tunnel space, affecting the quality of the test wind field; the passive damping of the spring system is difficult to accurately match the 0.1%-0.5% damping ratio requirement of the actual bridge.

[0004] Therefore, it is necessary to provide a low-damping bridge wind-resistant segment model test suspension device that can provide a high-quality wind field. Summary of the Invention

[0005] The purpose of the present invention is to provide a zero-damping magnetic levitation wind tunnel segment model test device to solve the above-mentioned technical defects. By replacing the traditional spring suspension with magnetic levitation, zero-damping suspension of the segment model in the wind tunnel test is achieved, so that the dampers can be flexibly arranged according to the test requirements and the test damping ratio can be adjusted steplessly. In addition, the test device of the present invention greatly reduces the cross-sectional proportion of the support device, has less interference with the airflow, and the obtained wind field quality is better.

[0006] The present invention discloses a zero-damping magnetic levitation wind tunnel segment model test device, comprising a segment model, a laser displacement meter, an adjustment device and a guide rail device. The adjustment device comprises a damping adjustment device and a magnetic levitation adjustment device. The damping adjustment device is connected to the four corners of the segment model. The magnetic levitation adjustment device is arranged below the segment model. The damping adjustment device is clamped and connected to the guide rail device. The guide rail device is fixed to the top plate and bottom plate of the wind tunnel laboratory.

[0007] Preferably, the damping adjustment device includes a thin steel wire rope and a damper arranged on the thin steel wire rope, the segment model is arranged on the thin steel wire rope, and the damper is arranged above and below the segment model.

[0008] Preferably, the magnetic levitation adjustment device includes an electromagnet, and the electromagnet is provided with two columns. The laser displacement meter is connected to the electromagnet through a control system and a transmission line. The magnitude of the magnetic force of the electromagnet is controlled by an electric current. The effective magnetic buoyancy force of the electromagnet is linearly related to the magnetic levitation distance between the segment model and the bottom plate of the wind tunnel laboratory. Since the vortex-induced vibration force is related to the amplitude of the vortex-induced vibration, the vortex-induced vibration is theoretically simplified to a single-degree-of-freedom vibration model. In order to maintain the linear relationship of the equivalent stiffness, it is usually hoped that the vortex-induced vibration is smaller than the linear deformation of the spring in the test. For the magnetic levitation system, its maximum effective suspension gap (maximum linear gap value) is required to be greater than the vortex amplitude value of the segment model in the test. The linear design of the magnetic buoyancy force and the suspension gap simplifies the complexity of the test and enhances the stability and safety of the system.

[0009] Preferably, a plurality of permanent magnets are embedded on both sides of the segment model. The number of electromagnets is equal to the number of permanent magnets, and the electromagnets and the permanent magnets are arranged at the same horizontal position to provide vertical rigidity for the segment model. The number of magnets arranged needs to be adjusted based on the weight of the segment model.

[0010] Preferably, the laser displacement meter is arranged on the bottom plate of the wind tunnel laboratory, at both ends of the single row of electromagnets.

[0011] Preferably, the guide rail device includes a guide magnet, a slide rail and a slider, the slider is in an I-shape, one end of the I-shaped slider is embedded in the slide rail, and the guide magnet is arranged on both sides of the slide rail.

[0012] Preferably, both side surfaces of the slider have the same magnetic properties, and the side of the guide magnet facing the slider has the same magnetic properties as the side surface of the slider.

[0013] Under wind loads, the torsional vibration of the segment model is driven by a thin steel wire rope, which drives the slider. Guide magnets provide restoring force, and the guide rail assembly provides torsional stiffness for the segment model. Using a thin steel wire rope in conjunction with the guide rail assembly to apply a damper to the segment model not only maintains the model's degrees of freedom during vibration but also avoids the additional damping introduced by rigid connections. The thin steel wire rope also has minimal impact on the wind field. Combined with the zero-damping magnetic levitation characteristics, this allows for more realistic simulation of vibration states and control of the damping ratio.

[0014] The segment model's damping is provided by external dampers. The contactless support ensures that the test system's inherent damping is close to zero. This allows for flexible damper placement and stepless adjustment of the test damping ratio based on test requirements. Compared to this device, a traditional spring suspension system may have a damping ratio greater than the required one, making it impossible to adjust the damping ratio during the test and reducing test reliability.

[0015] Therefore, the present invention adopts the above-mentioned zero-damping magnetic suspension wind tunnel segment model test device, which has the following beneficial effects:

[0016] (1) Stepless damping adjustment: The traditional spring suspension system has mechanical friction and initial damping. However, the present invention reduces mechanical friction through magnetic levitation contactless support and guide rail device, achieving zero damping of the segment model. In combination with an external damper, the damping of the segment model can be adjusted steplessly, greatly improving the matching accuracy between the damping of the segment model and the actual bridge.

[0017] (2) Better wind field quality: The segment model in the present invention is a magnetically suspended contactless support, and there are only thin steel wire ropes in the wind field, which makes the spatial cross-section of the support structure small, can greatly reduce the interference with the flow field, and provide better test wind field quality.

[0018] (3) Wider test range: Traditional spring suspension systems are prone to nonlinear distortion of stiffness due to large amplitudes, and are prone to response delays and nonlinear failures under high-frequency vibration or bending-torsion coupling conditions. However, the support device described in the present invention can maintain the linear response characteristics of stiffness in the torsional direction and can adapt to the requirements of large angle of attack and large amplitude tests.

[0019] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the overall structure of the zero-damping magnetic levitation wind tunnel segment model test device of the present invention;

[0021] Figure 2 This is a front view of the zero-damping magnetic levitation wind tunnel segment model test device of the present invention;

[0022] Figure 3 A side view of the zero-damping magnetic levitation wind tunnel segment model test device of the present invention;

[0023] Figure 4 This is a front cross-sectional view of the zero-damping magnetic levitation wind tunnel segment model test device of the present invention;

[0024] Figure 5 Schematic diagram of the guide rail device in the zero-damping magnetic levitation wind tunnel segment model test device of the present invention;

[0025] Figure 6 This is a front view of the guide rail device in the zero-damping magnetic suspension wind tunnel segment model test device of the present invention.

[0026] Figure 7 This is a cross-sectional view of the guide rail device in the zero-damping magnetic levitation wind tunnel segment model test device of the present invention;

[0027] Figure 8This is a relationship diagram between the effective magnetic buoyancy force and the magnetic levitation gap of the zero-damping magnetic levitation wind tunnel segment model test device of the present invention;

[0028] Reference numerals:

[0029] 1-top plate; 2-segment model; 3-guide rail device; 4-bottom plate; 5-control system; 6-damper; 7-thin steel wire rope; 8-transmission line; 9-laser displacement meter; 10-electromagnet; 11-permanent magnet; 31-guide magnet; 32-slide rail; 33-slider. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are 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 making creative efforts shall fall within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "surroundings", "horizontal", "longitudinal", "length", "thickness", "angle", "up", "down", "left", "right", etc., which indicate directions or positions, are limited to simplifying the description of the present invention, rather than specific positions or directions. The above terms are not limitations of the present invention.

[0032] The present invention provides a zero-damping magnetic suspension wind tunnel segment model test device, the structure of which is as follows: Figures 1-4 As shown, it includes a segment model 2, a laser displacement meter 9 arranged on the bottom plate 4 of the wind tunnel laboratory, an adjustment device and a guide rail device 3, the adjustment device includes a damping adjustment device and a magnetic levitation adjustment device, and the zero-damping magnetic levitation wind tunnel segment model 2 test device is fixed on the top plate 1 and the bottom plate 4 of the wind tunnel laboratory.

[0033] The damping adjustment device includes a thin steel wire rope 7 and a damper 6 arranged on the thin steel wire rope 7. The thin steel wire rope 7 is connected to the corners of the segment model 2, and the dampers 6 are arranged above and below the segment model 2.

[0034] The magnetic levitation adjustment device includes electromagnets 10 arranged in two rows. Laser displacement meters 9 are connected to the electromagnets 10 via a control system 5 and a transmission line 8. These laser displacement meters 9 are located at both ends of the single row of electromagnets 10. In this embodiment, four laser displacement meters are provided to measure the vertical displacement and torsion angle of the segment model 2.

[0035] The magnetic force of the electromagnet 10 is controlled by the current. Figure 8A graph showing the relationship between magnetic force and suspension gap is given, which shows that the linear relationship is transformed into a nonlinear relationship with the increase of the magnetic levitation gap. In this device, the effective magnetic levitation force of segment model 2 and the magnetic levitation gap are required to be linearly related during the wind tunnel test. Given that the vortex-induced vibration force is related to the amplitude of the vortex-induced vibration, the vortex-induced vibration is theoretically simplified to a single-degree-of-freedom vibration model. To maintain the linear relationship of the equivalent stiffness, it is usually hoped that the vortex-induced vibration is smaller than the linear deformation of the spring during the test. For the magnetic levitation system, the maximum effective suspension gap Δ1 is required to be greater than the maximum vortex amplitude of segment model 2 during the test [h a ], that is, Δ1>[h a ],[h a The linear design of the magnetic buoyancy force and the suspension gap simplifies the experimental complexity and enhances the system stability and safety.

[0036] Several permanent magnets 11 are embedded on both sides of the segment model 2. The number of electromagnets 10 is equal to the number of permanent magnets 11. The electromagnets 10 and permanent magnets 11 are arranged at the same horizontal position to provide vertical levitation force for the segment model 2. The number of magnets arranged needs to be adjusted based on the weight of the segment model 2.

[0037] Guide rail device 3 Figure 5-Figure 7 As shown, it includes a guide magnet 31, a slide rail 32 and a slider 33. The slider 33 is in an I-shape, with one end embedded in the slide rail 32, which limits the vertical movement of the slider 33 and allows it to move only horizontally. The guide magnet 31 is set on both sides of the slide rail 32, and the two ends of the thin steel wire rope 7 are set on the slider 33. Both sides of the slider 33 have the same magnetic properties. The side of the guide magnet 31 facing the slider 33 has the same magnetic properties as the side of the slider 33. When the segment model 2 begins to torsionally vibrate, it drives the thin steel wire rope 7 to move, and then drives the slider 33 to move horizontally in the slide rail 32. The guide magnet 31 provides a restoring force for the slider 33, providing torsional stiffness for the segment model 2.

[0038] Therefore, the present invention provides a zero-damping magnetic levitation wind tunnel segment model test device, which replaces the traditional spring suspension with magnetic levitation to achieve zero-damping suspension of the segment model in the wind tunnel test, so that the dampers can be flexibly arranged according to the test requirements and the test damping ratio can be adjusted steplessly; in addition, the test device of the present invention greatly reduces the cross-sectional proportion of the support device, has less interference with the airflow, and the obtained wind field quality is better.

[0039] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific implementation method of the present invention and does not limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A zero-damping magnetic levitation wind tunnel segment model test device, characterized in that: It includes a segment model, a laser displacement meter, an adjustment device and a guide rail device. The adjustment device includes a damping adjustment device and a magnetic levitation adjustment device. The damping adjustment device is connected to the four corners of the segment model. The magnetic levitation adjustment device is arranged below the segment model. The damping adjustment device is connected to the guide rail device by a snap-on connection. The guide rail device is fixed on the top and bottom plates of the wind tunnel laboratory.

2. A zero-damping magnetic levitation wind tunnel segment model test device according to claim 1, characterized in that: The damping adjustment device includes a thin steel wire rope and a damper arranged on the thin steel wire rope. The segment model is arranged on the thin steel wire rope, and the damper is arranged above and below the segment model.

3. A zero-damping magnetic levitation wind tunnel segment model test device according to claim 2, characterized in that: The magnetic levitation adjustment device includes electromagnets, which are arranged in two rows. The laser displacement meter is connected to the electromagnets through a control system and a transmission line. The magnetic force of the electromagnet is controlled by electric current. The effective magnetic levitation force of the electromagnet is linearly related to the magnetic levitation distance between the segment model and the bottom plate of the wind tunnel laboratory. The maximum effective levitation gap is greater than the vortex amplitude value of the segment model in the test.

4. A zero-damping magnetic levitation wind tunnel segment model test device according to claim 3, characterized in that: A plurality of permanent magnets are embedded on both sides of the segment model, the number of the electromagnets is equal to the number of the permanent magnets, and the electromagnets and the permanent magnets are arranged at the same horizontal position.

5. A zero-damping magnetic levitation wind tunnel segment model test device according to claim 4, characterized in that: The laser displacement meters are arranged on the bottom plate of the wind tunnel laboratory and are located at both ends of the single row of electromagnets.

6. A zero-damping magnetic levitation wind tunnel segment model test device according to claim 4, characterized in that: The guide rail device includes a guide magnet, a slide rail and a slider. The slider is I-shaped, one end of the I-shaped slider is embedded in the slide rail, the guide magnet is arranged on both sides of the slide rail, and the two ends of the thin steel wire rope are arranged on the slider.

7. A zero-damping magnetic levitation wind tunnel segment model test device according to claim 6, characterized in that: Both side surfaces of the slider have the same magnetic properties, and the side of the guide magnet facing the slider has the same magnetic properties as the side surface of the slider.

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