Tuned mass damping device for controlling low-frequency vertical bending vortex vibration of large-span bridge

Abstract

The invention belongs to the technical field of vibration control, and discloses a tuned mass damping device for controlling low-frequency vertical bending vortex vibration of a large-span bridge, which consists of a fixed pulley, a mass block, a high-strength light force transmission cable, a spring, a hanging ring and a damper. Fixed pulleys and mass blocks are arranged at the positive and negative maximum displacement positions of a longitudinal bridge direction mode of a main beam respectively, a suspension system is formed by a full-length force transmission cable, and the gravity of the two mass blocks is basically balanced; the mass block is connected through the spring and is close to the bridge vibration control target frequency. When the bridge vibrates, the two mass blocks generate inertia forces which are opposite in direction but overlapped with each other, the driving system and the bridge form resonance, and therefore bridge vibration is effectively restrained. The gravity of the mass block can be self-balanced, the strength and the number of the springs are greatly reduced compared with those of a traditional TMD, any low-frequency tuning can be conducted in a vertical limited space, and the engineering cost is remarkably reduced. The device can be used for controlling vertical bending and torsional vibration of various engineering structures; the damper is replaced by an actuator, so that active control can be realized or the damper can be used as a structural excitation device.

Description

Technical Field

[0001] This invention belongs to the field of vibration control technology and relates to a tuned mass damping device for controlling low-frequency vertical bending vortex-induced vibration of long-span bridges. Background Technology

[0002] Vertical vortex-induced vibrations occur frequently in long-span bridges. Although they usually do not endanger structural safety, they can affect driving comfort and may easily cause public panic. As bridge spans continue to increase, the frequency of vertical vortex-induced vibrations in the main girder may decrease to below 0.2Hz. In this low-frequency range, traditional spring-supported tuned mass dampers (TMDs) are difficult to use in situations with limited vertical space (typically 2.5-4m) in the main girder due to excessive static deformation. Tuned mass capacitive dampers (TMDIs) can achieve even lower operating frequencies in limited spaces, but under the same mass conditions, their control efficiency and robustness are weaker than traditional TMDs. They often require a significant increase in the mass of the mass block to ensure control effectiveness, which inevitably increases the structural load and engineering cost, resulting in poor applicability and difficulty in engineering implementation. Therefore, there is an urgent need for a vertical vortex-induced vibration control device that can achieve low-frequency tuning within a limited height, requires minimal springs, and is cost-effective.

[0003] To address the aforementioned problems, this invention proposes a tuned mass damping device (TMD) for controlling low-frequency vertical bending vortex-induced vibration in long-span bridges. Depending on the target vortex-induced vibration mode to be controlled (e.g., first-order or higher-order symmetric / anti-symmetric vertical bending), fixed pulleys and mass blocks are respectively installed at the points of maximum positive and maximum negative displacement of the mode in the longitudinal direction of the bridge. The two mass blocks are suspended from the two fixed pulleys by a long rope, ensuring that the gravity of the two mass blocks is essentially balanced. A short spring connects the mass blocks, enabling arbitrary low-frequency tuning of the vibration system. This solves the problems of excessively long springs and limited installation space required by traditional TMDs, significantly reduces the number of springs used, and substantially lowers the device's engineering cost. Summary of the Invention

[0004] Based on the above-mentioned technical problems, the present invention provides a tuned mass damping device for controlling low-frequency vertical bending vortex-induced vibration of long-span bridges.

[0005] The technical solution of the present invention:

[0006] A tuned mass damping device for controlling low-frequency vertical bending vortex-induced vibration of a long-span bridge includes a fixed pulley 1, a mass block, a force transmission cable 4, and a spring. For controlling the first-order anti-symmetric vertical bending vortex-induced vibration of a long-span bridge, the corresponding vibration mode has two maximum displacement sections with equal magnitude and opposite direction of vibration displacement in the longitudinal direction of the bridge. The fixed pulley 1, mass block, spring, and force transmission cable 4 are respectively installed inside the main beam of the two maximum displacement sections. The mass block is divided into a first mass block 2 and a second mass block 3, and the spring is divided into a first spring 5 and a second spring 6. The two ends of the force transmission cable 4 are respectively connected to the mass block and suspended on the fixed pulley 1 of the maximum displacement section. One end of the first spring 5 and the second spring 6 are respectively connected to the first mass block 2 and the second mass block 3, and the other end is connected to the long-span bridge.

[0007] Furthermore, the tuned mass damping device also includes lifting rings 7, and the force transmission cable 4 is supported by several lifting rings 7 suspended at intervals on the top plate of the main beam, so that the force transmission cable 4 is in a horizontal state.

[0008] Furthermore, the tuned mass damping device also includes a damper, which is placed between the mass block and the bridge to adjust the damping ratio of the tuned mass damping device.

[0009] Furthermore, by replacing the damper with an actuator or replacing the damper with an actuator while removing the spring, active control of vertical bending vortex vibration can be achieved.

[0010] Furthermore, for controlling the first-order symmetrical vertical bending vortex-induced vibration, higher-order anti-symmetrical vertical bending vortex-induced vibration, or higher-order symmetrical vertical bending vortex-induced vibration of long-span bridges, the position of the fixed pulley (1) and the mass block in the tuned mass damping device for the first-order anti-symmetrical vertical bending vortex-induced vibration of long-span bridges is adjusted. The position adjustment follows the following two criteria: ① The two mass blocks are installed as close as possible to the area near the maximum vertical relative displacement in the corresponding vibration mode; ② The horizontal distance between the two mass blocks is as small as possible.

[0011] The beneficial effects of this invention are: (1) It abandons the idea that the weight of the traditional TMD mass block is borne entirely by the spring, and divides the mass block into two parts and sets them on different sections of the bridge. All or most of their weight is self-balancing. When the bridge vibrates, the two parts of the mass block vibrate in opposite directions. The inertial forces will not cancel each other out, but will instead be superimposed, driving the mass block to resonate significantly and controlling the bridge vibration; (2) Since the mass block is self-balancing entirely or most of its weight, the spring does not need to bear the weight of the mass block, or only bears a small part of the weight of the mass block. During the vibration of the mass block, the spring only needs to be kept in a taut state. Therefore, the strength and number of springs are significantly reduced compared to the traditional TMD. 3) The spring deformation only needs to meet the amplitude requirements of the mass block, so that the tuned mass damping device can achieve arbitrary low-frequency tuning in the main beam with limited vertical installation space (2.5-4m); (4) Although this invention is mainly designed for low-frequency vertical bending vibration control of long-span bridges, it can also be applied to the control of higher frequency vertical bending and torsional vibration of various structures as appropriate, since it can save a lot of springs; (5) The damper of this tuned mass damping device is replaced with an actuator, and an active mass damper can be formed without springs. The mass of the mass block is greatly reduced and the vibration control efficiency is greatly improved; the adjusted device can also be used as a vibration excitation device for bridges, so it has powerful functions. Attached Figure Description

[0012] Figure 1 Schematic diagram of a tuned mass damping device for controlling low-frequency vertical bending vortex-induced vibration in long-span bridges

[0013] Figure 2 Schematic diagram of vibration modes of long-span bridges

[0014] In the diagram: 1. Fixed pulley, 2. First mass block, 3. Second mass block, 4. High-strength lightweight force transmission cable, 5. First spring, 6. Second spring, 7. Ring, 8. First damper, 9. Second damper. Detailed Implementation

[0015] The specific embodiments of the present invention will be described in detail below with reference to the technical solutions and accompanying drawings.

[0016] like Figure 1 As shown, the present invention proposes a tuned mass damping device for controlling low-frequency vertical bending vortex-induced vibration of long-span bridges, comprising a fixed pulley 1, a first mass block 2, a second mass block 3, a force transmission cable 4, a first spring 5, a second spring 6, a lifting ring 7, a first damper 8, and a second damper 9.

[0017] For controlling the first-order antisymmetric vertical bending vortex-induced vibration of a long-span suspension bridge, the corresponding vibration mode typically has two maximum displacement sections with equal magnitude and opposite directions in the longitudinal direction of the bridge. Fixed pulleys 1, mass blocks, springs, and force transmission cables 4 are installed inside the main beam at these two maximum displacement sections. The two ends of the force transmission cable 4 are connected to the mass blocks and suspended supports on the fixed pulleys 1 at the maximum displacement sections, respectively. One end of the first spring 5 and the second spring 6 are connected to the first mass block 2 and the second mass block 3, respectively, and the other end is connected to the bridge. This is used for frequency tuning of the entire mass-spring vibration system, bringing it closer to the target frequency of the controlled vortex-induced vibration mode to facilitate resonance and control the bridge's vortex-induced vibration. Since the horizontal distance between the first mass block 2 and the second mass block 3 inside the bridge is usually large, the force transmission cable 4 is supported by several hanging rings 7 suspended from the top plate of the main beam at intervals, keeping it basically horizontal and eliminating its nonlinear stiffness effect. Depending on actual needs, a damper is installed between the mass blocks and the bridge to adjust the damping ratio of the tuned mass damping device to near its optimal value. When a bridge vibrates, the inertial forces of the two mass blocks are opposite, and the mass blocks resonate with the bridge, controlling the bridge's vibration.

[0018] For controlling the first-order symmetrical vertical bending vortex-induced vibration, the second-order anti-symmetrical vertical bending vortex-induced vibration, or the third-order symmetrical vertical bending vortex-induced vibration of a long-span bridge, the position of the mass blocks in the tuned mass damping device for controlling the first-order anti-symmetrical vertical bending vortex-induced vibration of a long-span bridge is adjusted. The selection of the positions of the first mass block 2 and the second mass block 3 follows the following two criteria: ① The two mass blocks are installed at the point of maximum vertical relative displacement in the corresponding vibration mode, thereby generating greater inertial force, achieving greater amplitude and more energy dissipation; ② The horizontal distance between the two mass blocks is minimized, thereby shortening the length of the force transmission cable 4 and reducing the number of lifting rings 6. In actual engineering, sometimes, in order to shorten the horizontal distance between the first mass block 2 and the second mass block 3, one mass block may be placed at the vibration stagnation point (i.e., where no vertical vibration occurs), or even placed at the point where the vibration displacement is in the same phase (note that it is not the point where the displacement is the same, but the point where the vibration direction is the same, in which case the inertial force will partially cancel each other out). The optimal solution is achieved by considering multiple factors.

[0019] In a static equilibrium state, the first mass block 2 and the second mass block 3 are suspended, and most or even all of their weight cancels each other out. The springs mainly bear the inertial force during the vibration of the mass blocks. During the vibration of the bridge, the two mass blocks vibrate in opposite directions, but the inertial forces they generate are superimposed in the same direction in the force transmission system, thus effectively driving the device to work. If the first mass block 2 and the second mass block 3 have equal masses, their self-weights completely cancel each other out, requiring the arrangement of a first spring 5 and a second spring 6. The first spring 5 and the second spring 6 can be the same or different, and both must be in a tensioned state. If the first mass block 2 and the second mass block 3 have different masses, only the first spring 5 or the second spring 6, or both, need to be arranged. In short, the first spring 5 and / or the second spring 6 do not need to bear the entire self-weight of the mass blocks as in traditional tuned mass damping devices, significantly reducing the force requirements of the springs. Therefore, under the same mass block conditions, the number of springs required by this device can be significantly reduced, possibly only 10% of that of traditional TMD springs, or even less; and the lower the vibration frequency, the greater the reduction rate of spring usage. Furthermore, the working deformation of the spring is no longer limited by the tuning frequency, enabling the device to achieve extremely low frequency tuning requirements within the limited vertical space of the bridge (typically 2.5-4m).

[0020] The specific form, type, and number of the fixed pulley 1 are not limited, but it should have a low coefficient of friction and a large wheel diameter. This ensures that the rotation angle of the fixed pulley 1 is as small as possible under the same vertical amplitude conditions as the first mass block 2 and the second mass block 3, thereby ensuring that the damping ratio of the tuned mass damping device is lower than the optimal damping ratio required by the tuned mass damping device.

[0021] The material, type, and quantity of the first mass block 2 and the second mass block 3 are not limited, and their masses can be equal or unequal.

[0022] The material of the force transmission cable 4 is not limited, and it can be a fiber material with high stiffness, high strength and low density.

[0023] The material and type of the first spring 5 and the second spring 6 are not limited. They can be tension coil springs, compression coil springs or other elastic components. As needed, the first spring 5 and the second spring 6 can be the same or different, or only the first spring 5 or the second spring 6 can be provided.

[0024] The material, size, type, and quantity of the lifting ring 7 are not limited, and other lightweight flexible components can also be used to achieve the function of suspending the force transmission cable 4. Because the force transmission cable 4 is very lightweight, the frictional damping between it and the lifting ring 7 is very small.

[0025] The specifications, type, and quantity of the first damper 8 and the second damper 9 are not limited, and the connection method with the mass block is not limited. They are used to adjust the damping ratio of the tuned mass damping device to be close to the optimal value. The first damper 8 and the second damper 9 can be the same or different. Under certain conditions, the tuned mass damping device may not require the first damper 8 and / or the second damper 9 to compensate for the damping ratio, which can further save costs.

[0026] By replacing the first damper 8 and the second damper 9 with actuators, the first spring 5 and the second spring 6 are no longer needed, thus converting it into an active mass damper. Even with a significant reduction in the mass of the first mass block 2 and the second mass block 3, the vibration control efficiency can be greatly improved. This tuned mass damping device can also be used as a vibration excitation device for bridges when moved to the bridge deck.

[0027] This device differs from traditional TMDs in its force application and operating mode. It can achieve arbitrary low-frequency vibration control within a limited vertical space using a small number of springs. For high-frequency vertical vibrations, it can also reduce the amount of springs required. However, as the frequency increases, the amount of springs and the required vertical space decrease significantly, making the advantages of this tuned mass damping device relatively weaker. Its advantages are more pronounced for frequencies below 0.4Hz. Arranging this tuned mass damping device on both sides of a transverse bridge can also control torsional vortex-induced vibrations, and even torsional flutter and flexural-torsional coupled flutter. This tuned mass damping device is not limited to bridge vibration control but can also be used for vibration control of other engineering structures.

[0028] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any equivalent changes, modifications, or variations made by those skilled in the art to the above examples using the technical solutions of the present invention shall still fall within the scope of the technical solutions of the present invention.

Claims

1. A tuned mass damper device for controlling low frequency vertical bending vortex vibration of a long span bridge, characterized in that, The tuned mass damper device comprises a fixed pulley (1), a mass block, a force transmission cable (4) and a spring; for controlling the first-order anti-symmetrical vertical bending vortex of a long-span bridge, the corresponding vibration mode has two maximum displacement sections in the longitudinal direction of the bridge, with equal vibration displacement and opposite directions; the fixed pulley (1), the mass block, the spring and the force transmission cable (4) are arranged inside the two maximum displacement sections, respectively; the mass block is divided into a first mass block (2) and a second mass block (3), and the spring is divided into a first spring (5) and a second spring (6); the force transmission cable (4) is connected to the mass blocks at both ends and is suspended on the fixed pulley (1) at the maximum displacement sections; one end of the first spring (5) and the second spring (6) is connected to the first mass block (2) and the second mass block (3), respectively, and the other end is connected to the long-span bridge.

2. The tuned mass damper device for controlling low-frequency vertical bending vortex vibration of a long-span bridge according to claim 1, characterized in that, The tuned mass damper device further comprises a lifting ring (7), and the force transmission cable (4) is supported by the lifting ring (7) suspended on the top plate of the main girder at intervals, so that the force transmission cable (4) is in a horizontal state.

3. The tuned mass damper device for controlling low-frequency vertical bending vortex vibration of a long-span bridge according to claim 1, characterized in that, The tuned mass damper device further comprises a damper, and the damper is arranged between the mass block and the bridge, for adjusting the damping ratio of the tuned mass damper device.

4. The tuned mass damper device for controlling low-frequency vertical bending vortex vibration of a long-span bridge according to claim 3, characterized in that, The damper is replaced by an actuator, or the damper is replaced by an actuator while the spring is removed, so as to realize active control of the vertical bending vortex.

5. The tuned mass damper device for controlling low frequency vertical bending vortex vibration of a long-span bridge according to claim 1, wherein For controlling the first-order symmetric vertical bending vortex, the high-order anti-symmetric vertical bending vortex or the high-order symmetric vertical bending vortex of a long-span bridge, the positions of the fixed pulley (1) and the mass block in the tuned mass damper device for controlling the first-order anti-symmetric vertical bending vortex of the long-span bridge are adjusted, and the position adjustment follows the following two criteria: ① the two mass blocks are installed as close as possible to the positions with the maximum vertical relative displacement in the corresponding vibration mode; and ② the horizontal distance between the two mass blocks is as small as possible.

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