Magnetic circuit structure of a pendulum-type eddy current tuned mass damper with isotropic damping coefficient

Abstract

The present invention relates to the field of structural vibration control, and more specifically to a magnetic circuit structure for a pendulum-type eddy current tuned mass damper (TMD) with an isotropic damping coefficient, comprising a permanent magnet back iron and a conductor disk back iron disposed oppositely, the permanent magnet back iron being fixedly mounted with at least one annular permanent magnet group, the annular permanent magnet group comprising two concentrically arranged annular permanent magnets with an air gap between them, both of which are axially magnetized and have opposite magnetic poles, the conductor disk back iron being fixedly mounted with a conductor disk, and the relative motion between the annular permanent magnet and the conductor disk generating an eddy current damping effect. The magnetic circuit structure of the present invention utilizes axially magnetized annular permanent magnets to provide the pendulum-type TMD with identical damping coefficients in all vibration directions, thereby achieving optimal parameter design of the pendulum-type TMD in all directions and maximizing the vibration reduction control effect of the pendulum-type TMD.

Description

Technical Field

[0001] The invention relates to the technical field of structural vibration control, in particular to a magnetic circuit structure of a pendulum-type eddy current tuned mass damper with isotropic damping coefficient. Background Art

[0002] Large-span, high-rise, and towering structures are generally characterized by their light mass, low damping, and low frequency. These structures are highly susceptible to large vibrations under dynamic loads such as strong winds and earthquakes, which can severely impact their normal operation and even endanger their safety. Structural vibration control technology can overcome the limitations and inflexibility of traditional structural designs in resisting natural disasters of unknown magnitude. It can significantly enhance the ability of civil engineering structures to suppress various types of harmful vibrations, ensuring their safety and even normal operation during earthquakes and strong winds. Numerous methods exist for structural vibration control, each with its own advantages but also limitations. The tuned mass damper (TMD) is a type of vibration reduction device that utilizes the principle of dynamic energy absorption to control structural vibration. It primarily consists of a mass element, a spring element, and a damping element. The spring element tunes its frequency to that of the main structure, and through frequency tuning, achieves resonance, transferring the vibration energy of the main structure to the mass element, which is then dissipated by the damping element. Currently, TMDs are widely used to control vertical vortex-induced vibrations in long-span continuous steel box girder bridges, wind-induced vibrations in high-rise and tall structures, and human-induced vibrations in long-span pedestrian bridges. For example, the Tokyo Bay Channel Bridge in Japan uses vertical TMDs to control vortex-induced vibrations; the Shanghai Tower and the Guangzhou Tower both employ TMDs to control wind-induced vibrations; and the Zhangjiajie Glass Bridge uses horizontal TMDs to control human-induced vibrations. Wind-induced vibrations in high-rise and tall structures are primarily horizontal, and due to the randomness of wind direction, these structures may vibrate in all directions across their cross-section. Therefore, pendulum-type TMDs, with their adaptive horizontal vibration direction, are widely used in vibration control of high-rise and tall structures.

[0003] Damping elements are the energy-dissipating components of a pendulum TMD, significantly impacting its control efficiency and vibration reduction effectiveness. For tall or high-rise structures with circular cross-sections (such as chimneys and thermal towers), the modal mass, frequency, and damping are identical in all vibration directions. Therefore, the optimal damping parameters for the corresponding pendulum TMD are also identical in all directions. If the damping elements fail to provide uniform damping coefficients in all directions, the control efficiency will inevitably be suboptimal in certain vibration directions. Traditional pendulum TMDs typically use oil dampers as damping elements. To accommodate the isotropic vibrations of the building and the pendulum itself, multiple oil dampers are typically arranged along the circumference of the pendulum mass. However, the number of circumferentially arranged oil dampers is always limited. Therefore, even if the damping coefficients of each oil damper are identical, the damping coefficients of the pendulum TMD cannot be uniform in all vibration directions, thus failing to achieve optimal isotropic control. In recent years, pendulum-type TMDs have begun to employ permanent magnet plate-type eddy current damping units as damping elements. These advantages include addressing the issue of oil damping, which is prone to oil leakage and failure, while also avoiding the complex mechanical connection between the oil damper, the mass block, and the structure, significantly improving the starting sensitivity of the pendulum-type TMD. However, the plate-type eddy current damping units used in existing pendulum-type TMDs also struggle to meet the requirement for isotropic damping coefficients. For example, Chinese invention patent publication number CN106337591A discloses a method and device for designing a magnetic circuit structure for a pendulum-type eddy current TMD, in which the permanent magnets are arranged with their poles staggered along the direction of mass motion and with their poles aligned perpendicular to the direction of motion. While this arrangement improves the damping coefficient of the pendulum-type TMD along the staggered pole arrangement, the asymmetric polarity of the permanent magnets in all directions results in a significantly lower damping coefficient in the direction where the poles are aligned. This prevents the pendulum-type TMD from achieving optimal parameter design in all directions, impacting its energy efficiency and vibration reduction effectiveness. Summary of the Invention

[0004] The purpose of the present invention is to provide a pendulum eddy current tuned mass damper magnetic circuit structure with isotropic damping coefficient to address the problem that the pendulum TMD in the prior art cannot achieve optimal parameter design in all directions, which affects its energy consumption efficiency and vibration reduction effect.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A magnetic circuit structure of a pendulum-type eddy current tuned mass damper with an isotropic damping coefficient comprises a permanent magnet back iron and a conductor disk back iron arranged in opposite directions. The permanent magnet back iron is fixedly mounted with at least one annular permanent magnet group, the annular permanent magnet group comprising two concentrically arranged annular permanent magnets with an air gap between them. Both the annular permanent magnets are axially magnetized structures with opposite magnetic poles. The conductor disk back iron is fixedly mounted with a conductor disk. The eddy current damping effect is generated by the relative movement between the annular permanent magnet and the conductor disk.

[0007] The magnetic circuit structure described in the present invention uses axially magnetized annular permanent magnets, which can provide the pendulum TMD with exactly the same damping coefficient along all vibration directions, thereby achieving optimal parameter design of the pendulum TMD along all directions and maximizing the vibration reduction control effect of the pendulum TMD.

[0008] As a preferred embodiment of the present invention, the permanent magnet back iron is fixedly mounted with at least two groups of annular permanent magnets. All of the annular permanent magnet groups are concentrically arranged with an air gap between adjacent groups, and the magnetic poles of all of the annular permanent magnets are alternately arranged radially. By providing multiple groups of annular permanent magnets, the vibration control effect can be improved.

[0009] As a preferred embodiment of the present invention, the annular permanent magnet is an integral annular structure. For a small pendulum TMD structure, the use of an integral annular permanent magnet can simplify the installation and construction process.

[0010] As a preferred embodiment of the present invention, the annular permanent magnet comprises a plurality of mutually pressed sector-shaped permanent magnets, all of which form a complete annular structure. For medium and large-sized pendulum TMD structures, the use of multiple sector-shaped assembly can improve installation accuracy and efficiency.

[0011] As a preferred solution of the present invention, the radial widths of the annular permanent magnets are the same.

[0012] As a preferred solution of the present invention, the radial widths of the annular permanent magnets are different and can be designed to be equal or unequal in width according to the magnitude of the damping force.

[0013] The present invention also discloses a pendulum-type eddy current tuned mass damper with isotropic damping coefficient, comprising a mass block and a magnetic circuit structure of the pendulum-type eddy current tuned mass damper with isotropic damping coefficient. The annular permanent magnet group is fixedly connected to the mass block through the permanent magnet back iron, and the annular permanent magnet group swings 360° circumferentially with the mass block. The conductor disk is fixedly installed on a horizontal plane through the conductor disk back iron.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0015] 1. The magnetic circuit structure described in the present invention uses axially magnetized annular permanent magnets to provide the pendulum TMD with exactly the same damping coefficient along all vibration directions, thereby achieving optimal parameter design of the pendulum TMD along all directions and maximizing the vibration reduction control effect of the pendulum TMD.

[0016] 2. For small pendulum TMD structures, the use of integral annular permanent magnets can simplify the installation and construction process.

[0017] 3. The pendulum TMD of the present invention adopts the above-mentioned magnetic circuit structure, which realizes the optimal design of the parameters of the pendulum TMD in all directions, thereby maximizing the vibration reduction control effect of the pendulum TMD. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a top view of the magnetic circuit structure described in Example 1 of the present invention.

[0019] Figure 2 It is a cross-sectional view of the magnetic circuit structure described in Example 1 of the present invention.

[0020] Figure 3 It is a top view of the magnetic circuit structure described in Example 2 of the present invention.

[0021] Figure 4 It is a cross-sectional view of the magnetic circuit structure described in Example 2 of the present invention.

[0022] Figure 5 It is a top view of the magnetic circuit structure described in Example 3 of the present invention.

[0023] Figure 6 It is a cross-sectional view of the magnetic circuit structure described in Example 3 of the present invention.

[0024] Figure 7 It is a structural diagram of 4×4 co-directional magnets.

[0025] Figure 8 This is a schematic diagram of the eddy current damping coefficient of 4×4 magnets in the same direction at different swing azimuth angles.

[0026] Figure 9 It is a schematic diagram of the eddy current damping coefficient of the pendulum eddy current tuned mass damper with isotropic damping coefficient at different swing azimuth angles described in the present invention.

[0027] Icon: 1-first annular permanent magnet, 2-second annular permanent magnet, 3-third annular permanent magnet, 4-fourth annular permanent magnet, 5-permanent magnet back iron, 6-conductor disk, 7-conductor disk back iron. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to the accompanying drawings.

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] Example 1

[0031] like Figure 1-2 As shown, a magnetic circuit structure of a pendulum-type eddy current tuned mass damper with an isotropic damping coefficient includes a permanent magnet back iron 5 and a conductor disk back iron 7 arranged in opposite directions. The permanent magnet back iron 5 is fixedly installed with at least one group of annular permanent magnet groups. The annular permanent magnet group includes two concentrically arranged annular permanent magnets with an air gap between the two annular permanent magnets. The two annular permanent magnets are both axially magnetized structures with opposite magnetic poles. The conductor disk back iron 7 is fixedly installed with a conductor disk 6. The eddy current damping effect is generated by the relative movement between the annular permanent magnet and the conductor disk 6.

[0032] In this embodiment, the number of annular permanent magnet groups is one group, specifically, including a first annular permanent magnet 1 and a second annular permanent magnet 2, the first annular permanent magnet 1 and the second annular permanent magnet 2 are concentrically arranged and separated by an air gap, the first annular permanent magnet 1 and the second annular permanent magnet 2 are both axially magnetized structures, and along the radial direction of the annular permanent magnet, the magnetic poles of the first annular permanent magnet 1 and the second annular permanent magnet 2 are alternately arranged.

[0033] As an optional embodiment, the annular permanent magnet is an integral annular structure, which is suitable for a small pendulum TMD structure and can simplify the installation and construction process.

[0034] The radial widths of the annular permanent magnets can be designed to be equal or unequal according to the magnitude of the damping force.

[0035] Example 2

[0036] Unlike Example 1, in this embodiment, the permanent magnet back iron 5 is fixedly mounted with N (N ≥ 2) annular permanent magnet groups. All annular permanent magnet groups are concentrically arranged, with air gaps between adjacent annular permanent magnet groups. The magnetic poles of all annular permanent magnets are arranged alternately along the radial direction. By providing multiple annular permanent magnet groups, the vibration control effect can be improved.

[0037] like Figure 3-4As shown, in this embodiment, there are two annular permanent magnet groups, specifically, including not only the first annular permanent magnet 1 and the second annular permanent magnet 2, but also the third annular permanent magnet 3 and the fourth annular permanent magnet 4, wherein the first annular permanent magnet 1 and the second annular permanent magnet 2 constitute the first annular permanent magnet group, and the third annular permanent magnet 3 and the fourth annular permanent magnet 4 constitute the second annular permanent magnet group, the first annular permanent magnet 1, the second annular permanent magnet 2, the third annular permanent magnet 3 and the fourth annular permanent magnet 4 are all concentrically arranged and separated by an air gap, the first annular permanent magnet 1, the second annular permanent magnet 2, the third annular permanent magnet 3 and the fourth annular permanent magnet 4 are all axially magnetized structures, and along the radial direction of the annular permanent magnets, the magnetic poles of the first annular permanent magnet 1, the second annular permanent magnet 2, the third annular permanent magnet 3 and the fourth annular permanent magnet 4 are alternately arranged.

[0038] Example 3

[0039] like Figure 5-6 As shown, different from embodiment 2, in this embodiment, each annular permanent magnet includes a plurality of sector-shaped permanent magnets pressed against each other, and all the annular permanent magnets form a complete annular structure.

[0040] For medium and large-sized swing-type TMD structures, the use of multi-piece fan-shaped assembly can improve installation accuracy and efficiency.

[0041] Example 4

[0042] On the basis of Examples 1-3, this embodiment discloses a pendulum-type eddy current tuned mass damper with isotropic damping coefficient, comprising a mass block and a pendulum-type eddy current tuned mass damper magnetic circuit structure with isotropic damping coefficient described in any of Examples 1-3, wherein the annular permanent magnet group is fixedly connected to the mass block through the permanent magnet back iron 5, and the annular permanent magnet group swings 360° along the circumferential direction with the mass block, and the conductor disk 6 is fixedly installed on the horizontal plane through the conductor disk back iron 7.

[0043] In actual use, the magnetic circuit structure swings 360° along the circumferential direction together with the mass block and the controlled structure, and an eddy current damping effect is generated through the relative movement between the annular permanent magnet and the conductor disk 6.

[0044] Figure 7 The existing 4×4 structure of the same direction magnet is shown. Figure 8 The diagram shows the eddy current damping coefficient of 4×4 magnets in the same direction at different swing angles. Figure 9A schematic diagram shows the eddy current damping coefficients of the pendulum-type eddy current tuned mass damper (using a ring magnet array) at different swing angles. Simulation results demonstrate that the pendulum-type eddy current tuned mass damper (TMD) with isotropic damping coefficients provides identical damping coefficients in all vibration directions, thereby achieving optimal parameter design for the pendulum-type TMD in all directions and maximizing the vibration control effectiveness of the TMD.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements 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 magnetic circuit structure of a pendulum-type eddy current tuned mass damper with isotropic damping coefficient, characterized in that: The invention comprises a permanent magnet back iron and a conductor disk back iron arranged opposite to each other, wherein the permanent magnet back iron is fixedly mounted with at least one annular permanent magnet group, wherein the annular permanent magnet group comprises two concentrically arranged annular permanent magnets, with an air gap between the two annular permanent magnets, and both the annular permanent magnets are axially magnetized structures and each annular permanent magnet has opposite axial magnetic poles. Along the radial direction of the annular permanent magnets, the magnetic poles of the two annular permanent magnets are alternately arranged, and the conductor disk back iron is fixedly mounted with a conductor disk, and an eddy current damping effect is generated by the relative movement between the annular permanent magnet and the conductor disk. The annular permanent magnet is an integral annular structure, or the annular permanent magnet includes a plurality of sector-shaped permanent magnets pressed against each other, and all the annular permanent magnets form a complete annular structure.

2. The magnetic circuit structure of a pendulum-type eddy current tuned mass damper with isotropic damping coefficient according to claim 1, characterized in that: At least two groups of annular permanent magnet groups are fixedly installed on the permanent magnet back iron. All the annular permanent magnet groups are concentrically arranged, and there is an air gap between two adjacent annular permanent magnet groups. The magnetic poles of all the annular permanent magnets are alternately arranged along the radial direction.

3. The magnetic circuit structure of a pendulum-type eddy current tuned mass damper with isotropic damping coefficient according to any one of claims 1-2, characterized in that: The annular permanent magnets have the same radial width.

4. The magnetic circuit structure of a pendulum-type eddy current tuned mass damper with isotropic damping coefficient according to any one of claims 1-2, characterized in that: The annular permanent magnets have different radial widths.

5. A pendulum-type eddy current tuned mass damper with isotropic damping coefficient, comprising a mass block, characterized in that: It also includes a pendulum-type eddy current tuned mass damper magnetic circuit structure with isotropic damping coefficient as described in any one of claims 1-4, wherein the annular permanent magnet group is fixedly connected to the mass block through the permanent magnet back iron, the annular permanent magnet group swings 360° circumferentially with the mass block, and the conductor disk is fixedly installed on a horizontal plane through the conductor disk back iron.

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