Tmd group vibration control method for large-span floor under low-frequency wind vibration

Abstract

The application discloses a kind of TMD group vibration control technology under low-frequency wind vibration of large-span floor, comprising: 1) under the action of low-frequency fluctuation wind load, make large-span floor produce multiple easily excited modes;And 2) modal analysis is carried out, and according to the modal analysis result, TMD group is distributed on large-span floor;TMD includes upper cover plate (11), lower cover plate (12), multiple support springs (13), multiple spring guide shafts (14) and frequency-adjusted mass block (15);Two ends of spring guide shaft (14) are respectively arranged on upper cover plate (11) and lower cover plate (12), and frequency-adjusted mass block (15) is arranged between upper cover plate (11) and lower cover plate (12) by passing through spring guide shaft (14);The multiple support springs (13) are respectively sleeved on the multiple spring guide shafts (14), and are arranged below frequency-adjusted mass block (15), so as to support frequency-adjusted mass block (15).

Description

Technical Field

[0001] This invention relates to the field of vibration control technology, and in particular to a method for controlling the vibration of a large-span floor slab under low-frequency wind-induced vibration using a TMD (tuned mass damper) group. Background Technology

[0002] Currently, the following three solutions are generally adopted to address the vibration hazards of large-span floor slabs under low-frequency pulsating wind loads: 1) Reduce the span from large to small, increase stiffness, and reduce the impact of low-frequency vibrations. 2) Increase the cross-section or stiffness to reduce the impact of low-frequency vibrations. 3) Use local energy-dissipating supports.

[0003] However, all of the above solutions have shortcomings. For example, in Solution 1), since this project will test large equipment, reducing the span from a large span to a small span would result in a loss of space below, reducing the usable space of the project. In Solution 2), increasing the cross-section or stiffness of the floor slab would significantly increase the mass of the floor slab, consuming more materials and incurring huge economic costs. In Solution 3), viscous dampers have a good vibration reduction effect on wind-induced vibrations, but as the number of dampers increases, their installation location becomes a factor, and local energy-dissipating vibration damping supports are difficult to adjust and maintain.

[0004] Therefore, new technologies and methods are needed to at least partially address the shortcomings of existing technologies. Summary of the Invention

[0005] To address this issue, the present invention addresses the problem of amplified vibration harmonic response in large-span floor structures under low-frequency pulsating wind. It employs a distributed TMD group, which is space-saving and flexibly arranged within the large-span roof structure. The TMD group is optimized by utilizing the peak points of the vibration modes from the higher-order modal analysis of the floor structure, thereby controlling the vibration of the large-span floor to meet the requirements.

[0006] According to one aspect of the present invention, a method for controlling TMD group vibration under low-frequency wind-induced vibration of large-span floor slabs is provided, comprising:

[0007] 1) Under low-frequency pulsating wind loads, large-span floor slabs generate multiple easily excitable modes; and

[0008] 2) Perform modal analysis and, based on the results of the modal analysis, distribute the TMD clusters on the long-span floor slab.

[0009] The TMD includes an upper cover plate (11), a lower cover plate (12), multiple support springs (13), multiple spring guide shafts (14), and a frequency-modulated mass block (15). The two ends of the spring guide shaft (14) are respectively disposed on the upper cover plate (11) and the lower cover plate (12). The frequency-modulated mass block (15) passes through the spring guide shaft (14) and is disposed between the upper cover plate (11) and the lower cover plate (12). The multiple support springs (13) are respectively sleeved on the multiple spring guide shafts (14) and disposed below the frequency-modulated mass block (15), thereby supporting the frequency-modulated mass block (15).

[0010] According to an embodiment of the present invention, the frequency modulation quality block (15) is multiple blocks.

[0011] According to an embodiment of the present invention, the mass ratio of the frequency modulation mass block (15) to the mass of the large-span floor slab is μ, where 0.01 < μ < 0.05.

[0012] According to the embodiment of the present invention, step 2) includes determining the easily excitable modes and their mode shape participation coefficients based on modal analysis, determining their peak points and frequencies, determining the corresponding distributed TMD placement location and corresponding frequency based on the peak points of each easily excitable mode, and then determining the stiffness and mass of the TMD based on the placement location, frequency and overall mass of the floor structure of each distributed TMD.

[0013] According to an embodiment of the present invention, modal analysis accounts for 75% of the overall quality.

[0014] According to an embodiment of the present invention, the TMD is a post-supported type, which is installed after the large-span floor slab is constructed.

[0015] This invention primarily addresses the vibration hazards of large-span floor structures under low-frequency pulsating wind loads. It proposes a vibration control technology based on multi-mode analysis of the floor structure and the rational arrangement of a large-scale TMD (Transient Modal Damper) group. According to the TMD vibration reduction principle, considering that low-frequency pulsating loads easily excite multiple overall modes of the floor structure, the TMD group is optimally arranged using the peak positions of each easily excited mode, thereby suppressing the amplification of the floor structure's vibration harmonic response and reducing the hazards of low-frequency pulsation. Furthermore, the distributed, post-installed TMD dampers are small in mass and volume, facilitating their placement and post-installation adjustment.

[0016] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0017] Figure 1A schematic diagram of the TMD unit planar layout structure for a TMD group vibration control method under low-frequency wind vibration of a large-span floor slab according to the embodiment of the invention; and

[0018] Figure 2 This is a schematic diagram of the TMD structure for the TMD group vibration control method under low-frequency wind vibration of a large-span floor slab according to the embodiment of the invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the embodiments or descriptions are not intended to limit the scope of protection of the present invention. It should be understood that the finite element modeling, modal analysis and optimization design involved in the present invention are themselves known, therefore the present invention focuses on describing the combination of each step.

[0020] Figure 1 A schematic diagram of the TMD unit planar layout structure of the TMD group vibration control method for low-frequency wind vibration of large-span floor slabs according to the embodiment of the invention; Figure 2 This is a schematic diagram of the TMD structure for the TMD group vibration control method under low-frequency wind vibration of a large-span floor slab according to the embodiment of the invention.

[0021] Referring to the attached diagram, the TMD group vibration control method for large-span floor slabs under low-frequency wind vibration according to the implementation scheme includes: firstly, under the action of low-frequency pulsating wind load, the large-span floor slab generates multiple easily excitable modes; then, modal analysis is performed; and based on the modal analysis results, the TMD group is distributed on the large-span floor slab.

[0022] This solution addresses the resonance hazards caused by engineering vibrations in large-span floor slabs under low-frequency pulsating wind loads by establishing a distributed TMD (Transient Modulator) group layout. Due to the large span and the fact that the floor slab is a flexible system with a low overall fundamental frequency and relatively concentrated vibration modes, it is particularly suitable for frequency tuning and vibration reduction using TMDs. The distributed layout scheme places multiple small-volume and small-mass TMD dampers at effective placement points in the large-span floor slab. Considering multi-mode control under low-frequency pulsating wind loads, the distributed layout scheme can precisely control the vibration at the peak points of various easily excitation modes, effectively controlling the low-frequency vibrations of the steel truss structure and effectively solving the problems of insufficient space for large-span floor slab layout and multi-mode vibration control.

[0023] Furthermore, for modes easily excited by low-frequency pulsations in the entire floor slab, a refined detailed breakdown type of TMD (Modal Participation Mode) is proposed. The principle is to determine the easily excited modes and their mode participation coefficients based on modal analysis, identify their peak points and frequencies, determine the placement location and corresponding frequency of the distributed TMDs based on the peak points of each easily excited mode, and then determine the stiffness and mass of the TMDs (i.e., the TMD type) based on the placement location, frequency, and overall mass of the floor slab structure. A modal participation mass of 75% or more is sufficient to meet relevant specifications.

[0024] refer to Figure 2 The implementation scheme is a tuned mass damper (TMD), which consists of a tuned mass block (15), a support spring (13), and a support system. The vibration frequency of the TMD system is adjusted to be close to the vibration frequency of the structure. When the external force (earthquake, wind vibration) excites the vibration of the structure, the damper will generate a vibration that resonates in the opposite direction to the structure. At this time, the energy acting on the main structure will be transferred to the tuned mass damper and then dissipated.

[0025] The mass block used in the frequency modulation mass block (15) can be a concrete block, a steel box filled with lead, etc., and there can be one or more, with a mass of up to hundreds of tons. The size of the mass block is determined by the ratio of mass to the structural mass μ, and is generally selected as 0.01 < μ < 0.05.

[0026] The function of the support spring (13) is to provide restoring force to maintain the vibration of the mass block and to bear the weight of the mass block. The spring stiffness is determined by the working frequency of the TMD and the size of the mass block.

[0027] The support system includes an upper cover plate (11), a lower cover plate (12), a spring guide shaft (14), and anchor bolts (16), etc. Its main purpose is to assemble the various components into a whole, anchor the frequency-modulated mass damper unit, and connect it to the main structure. More specifically, the two ends of the spring guide shaft (14) are respectively set on the upper cover plate (11) and the lower cover plate (12), and the frequency-modulated mass block (15) passes through the spring guide shaft (14) and is set between the upper cover plate (11) and the lower cover plate (12); the multiple support springs (13) are respectively sleeved on the multiple spring guide shafts (14) and set below the frequency-modulated mass block (15), thereby supporting the frequency-modulated mass block (15). The anchor bolts (16) are used to fix the spring guide shaft and the upper and lower cover plates, and to fix the entire TMD to the roof.

[0028] The truss structure in the large-span steel truss roof 20 is commonly used in public buildings such as factories, exhibition halls, stadiums, and bridges with large spans. It is usually called a roof truss and is generally supported on concrete walls 30. It has advantages such as simple design, fabrication, and installation, and the ability of the truss to adapt to a wide range of spans, so its application is very widespread. However, it has low lateral stiffness and high flexibility, and is greatly affected by wind vibration, so vibration reduction and isolation measures are required.

[0029] Compared with existing technologies, the present invention can achieve beneficial technical effects:

[0030] 1) Large-scale TMD group in a distributed configuration. Due to the large span and the fact that the floor slab is a flexible system with a low overall fundamental frequency and relatively concentrated vibration modes, it is particularly suitable for frequency tuning and vibration reduction using TMDs. Utilizing the peak-to-peak positions of each excitation mode, a distributed arrangement of TMD groups is adopted. This TMD group scheme can effectively control the low-frequency vibration response of large-span roofs. Furthermore, when using a distributed configuration, the mass and volume of each individual TMD are relatively small, making placement convenient.

[0031] 2) Precise control capability. Based on the vibration reduction principle of TMD, this paper proposes to optimize the arrangement of large-scale TMD groups by utilizing the peak-peak positions of each mode shape, based on the fact that low-frequency pulsating loads can easily excite multiple overall modes of the floor slab. This achieves precise suppression of the vibration harmonic response of the floor slab and reduces the harm caused by low-frequency pulsation.

[0032] 3) Rear-mounted adjustable support. The TMD group adopts both rear-mounted and support types: the support type allows the TMD to be installed inside the roof, saving space; it can be installed after the roof construction is completed, and the damper position and parameters can be adjusted and maintained non-destructively in the later stages, which is conducive to improving the convenience and efficiency of later construction.

[0033] The present invention has been described above through specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should understand that various modifications, equivalent substitutions, and changes can be made to the present invention, and such changes, as long as they do not depart from the spirit of the present invention, should be within the protection scope of the present invention. Furthermore, the phrase "one embodiment" mentioned above refers to different embodiments, and of course, all or part of them can be combined in one embodiment.

Claims

1. A method for controlling TMD group vibration under low-frequency wind vibration of large-span floor slabs, characterized in that, include: 1) Under the action of low-frequency pulsating wind load, large-span floor slabs generate multiple easily excitable modes; as well as 2) Perform modal analysis and, based on the results of the modal analysis, distribute the TMD clusters on the long-span floor slab. The TMD includes an upper cover plate (11), a lower cover plate (12), multiple support springs (13), multiple spring guide shafts (14), and a frequency-modulated mass block (15). The two ends of the spring guide shafts (14) are respectively disposed on the upper cover plate (11) and the lower cover plate (12). The frequency-modulated mass block (15) passes through the spring guide shafts (14) and is disposed between the upper cover plate (11) and the lower cover plate (12). The multiple support springs (13) are respectively sleeved on the multiple spring guide shafts (14) and disposed below the frequency-modulated mass block (15), thereby supporting the frequency-modulated mass block (15). Step 2) includes determining the easily excitable modes and their mode shape participation coefficients based on modal analysis, determining their peak points and frequencies, determining the corresponding distributed TMD placement location and frequency based on the peak points of each easily excitable mode, and then determining the stiffness and mass of the TMD based on the placement location, frequency, and overall mass of the floor structure of each distributed TMD.

2. The method for controlling TMD group vibration under low-frequency wind vibration of large-span floor slabs according to claim 1, characterized in that, The frequency modulation quality block (15) consists of multiple blocks.

3. The method for controlling TMD group vibration under low-frequency wind vibration of large-span floor slabs according to claim 1, characterized in that, The mass ratio of the frequency-modulated mass block (15) to the mass of the large-span floor slab is μ, where 0.01 < μ < 0.

05.

4. The method for controlling TMD group vibration under low-frequency wind vibration of large-span floor slabs according to claim 1, characterized in that, Modal analysis contributes to 75% of the overall quality.

5. The method for controlling TMD group vibration under low-frequency wind vibration of large-span floor slabs according to claim 1, characterized in that, The TMD is a post-support type, installed after the large-span floor slab is constructed.

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