Low-frequency tuned mass damping device for reversely stretching compression spring

Abstract

The invention belongs to the technical field of low-frequency vibration control, and provides a low-frequency tuned mass damping device for reversely stretching a compression spring in order to solve the problem that a traditional tuned mass damper is limited in use of a vertical space due to too large net deformation of the spring under the low-frequency condition. According to the device, large compression deformation and reverse tensile deformation of the spring are fully realized in a limited vertical space in a manner of performing super-compression-reverse tensile treatment on the compression spring, relatively low rigidity required by a vibration system is achieved, low-frequency tuning can be realized in the limited vertical space of a bridge girder, and the rigidity of the vibration system is improved. The frequency application range of the tuned mass device is greatly expanded; and meanwhile, the problems that the stability problem is caused when a traditional compression spring mass body is arranged on the spring and the damping is too high and unstable due to the fact that a guide component is added are solved. The device is simple in structure, low in damping, low in space requirement and good in stability, and can be applied to vertical, lateral and torsional multi-type low-frequency vibration control of various engineering structures.

Description

Technical Field

[0001] This invention belongs to the field of low-frequency vibration control technology and relates to a low-frequency tuned mass damping device that reverses the stretching of a compression spring. Background Technology

[0002] Long-span bridges with main spans of over 1,000 meters may experience vertical or torsional vortex-induced vibrations (vortex-induced vibrations) with frequencies below 0.2 Hz under wind loads, affecting driving comfort and even safety. For example, the vortex-induced vibration frequencies of the Xihoumen Bridge and Humen Bridge in Zhejiang Province are as low as 0.1 Hz and 0.17 Hz, respectively. Traditional tuned mass dampers, if installed within a 3m vertical space within the main beam, can be used to control high-frequency (e.g., >0.3 Hz) vortex-induced vibrations in bridges. Tuned mass damper springs generally take the form of tension or compression, and their deformation under the action of the mass body... With vibration frequency Generally satisfied The relationship between tension springs and compression springs is complex. Tension springs offer flexible installation and structural stability, but for main beams with only 3-4m of vertical installation space, after deducting the original spring length, mass thickness, and vibration space, the space left for spring tensile deformation is at most 2-3m, making them suitable for frequencies generally no lower than 0.3Hz. Compression springs are compact and have a larger deformable range than tension springs. For main beams with 3-4m of vertical installation space, spring compression deformation can reach 6m or even 8m, theoretically suitable for vortex-induced vibration control at 0.15Hz. However, installation is difficult, and they face compressive stability issues, requiring additional lateral stabilization measures. This leads to complex construction and inevitably introduces frictional damping caused by the guiding device, which is difficult to control precisely, severely impacting vibration control effectiveness. To achieve lower vibration frequency tuning, inertial capacitance elements can be introduced to reduce the static deformation of the spring, but their control efficiency decreases significantly, and their control effect is more sensitive to various parameters such as frequency ratio and damping ratio. Their economic efficiency and applicability are also somewhat lacking, making them difficult to apply in practical engineering. Summary of the Invention

[0003] Addressing the technical limitations of traditional tuned mass dampers and tuned mass inertial-capacitive dampers in low-frequency vibration control, this invention aims to provide a novel concept: a tuned mass system with frequencies as low as 0.1Hz achieved by supporting a mass body with springs within a 3-4m vertical space of the main beam of a long-span bridge. Taking a compression spring with an initial length of approximately 25m as an example, the bottom coil of the spring is fixed, and compression is gradually applied from the top coil. Each coil of the spring is stretched in the opposite direction from the central hole or the outer periphery. Ultimately, all the original coils of the spring can be lower than the bottom coil. At this point, the compression spring becomes a reverse-tension spring, with an actual deformation exceeding 25m. Suspending a suitable mass ensures that the spring is essentially under tension, achieving a frequency as low as 0.1Hz.

[0004] The technical solution of the present invention:

[0005] A low-frequency tuned mass damping device for reverse stretching of a compression spring includes a helical compression spring, a mass body, and a damping element.

[0006] The helical compression spring is placed vertically, horizontally, or at an angle, with its bottom ring fixed to a correspondingly sized ring. Pressure is continuously applied to the top ring or a localized area within the spring until the top ring passes through or overlays the bottom ring, causing it to flip. The spring is then fixed in this flipped state. The bottom ring of the flipped spring is then mounted on the top plate of the box girder or the top of the box girder's internal support. In this state, the spring is in reverse rotation. The top ring, at its lowest movable end, connects to the mass body for suspension. The reverse-rotating spring balances the mass body's weight and provides stiffness to the vibration system, forming a tuning mass device. The original length of the helical compression spring is large, and its stiffness is low. After reverse stretching, although it occupies little space, it can withstand a significant weight of the mass body while maintaining a relatively constant low stiffness, thus enabling low-frequency tuning. Because the helical compression spring transitions from an initial compressed state to a tensile state, it avoids the instability issues common to compression springs and requires no additional lateral connection, resulting in very low damping. In addition, by setting appropriate parameters for damping elements as needed, additional damping can be provided for the low-frequency tuned mass damping device to achieve optimal control performance.

[0007] The material, size, and cross-sectional shape of the helical compression spring are not limited. To facilitate overcompression deformation and reverse tension, the spring index should be as large as possible (e.g., >20). It should be made into a tapered (tower-shaped) spring with a gradually changing outer diameter; the taper is not limited and can be designed according to requirements. Zero taper means a traditional constant-diameter spring. The larger the taper, the easier it is to perform overcompression and reverse tension, but the taper should not be too large, otherwise the strength and stiffness difference between adjacent coils will be large, resulting in unreasonable stress. An excessively long helical compression spring may not be convenient for overcompression and reverse tension; therefore, it can be segmented and flipped, and then connected in series. It can also be symmetrically arranged on both sides of a torsional vibration structure to control low-frequency torsional vibration. When the helical compression spring is used as a horizontal spring for low-frequency vibration control, and horizontal space is limited, the same treatment method can be used for horizontal helical compression springs to perform overcompression and reverse tension, achieving low-frequency tuning. The helical compression spring can be arranged vertically, horizontally, or inclined.

[0008] The specific material and structural form of the mass body are not limited. Compared with the mass body used in traditional tuned mass dampers (usually a steel plate with a high density), its space constraints are more relaxed. Therefore, concrete blocks or water tanks with lower density and lower cost by one or even two orders of magnitude can be used, which has strong competitiveness in engineering applications.

[0009] The damping element is used to adjust the damping of the low-frequency tuned mass damping device so that the system damping reaches the ideal target value and ensures the vibration control effect. Its form is not limited.

[0010] The beneficial effects of the present invention are as follows: (1) The initial compression spring is changed from being compressed to being stretched, and the axial stiffness remains basically unchanged. The deformation that can be achieved in the same vertical space is greater, so a lower frequency can be achieved compared with the traditional compression spring; (2) The traditional compression spring is always under compression and faces stability problems, while the spring of the present invention is always under tension and does not have stability problems; (3) The present invention does not require the addition of multiple layers of horizontal stabilizing plates or vertical guide rods. The structure is simple, the damping is low, the stability is good, and the vibration control efficiency is guaranteed; (4) A lower tuning frequency can be achieved in a limited vertical space, which greatly expands the frequency application range of the tuning mass device; (5) The spring of the present invention can be arranged vertically, horizontally, or inclined, and can be set as needed. The form is free and can be applied to the vertical, lateral and torsional low-frequency vibration control of various engineering structures, with a wide range of applicable scenarios. Attached Figure Description

[0011] Figure 1 This is a structural diagram of a low-frequency tuned mass damping device installed inside the main beam of a bridge, which over-compresses and reverse-stretches a compression spring.

[0012] Figure 2 This is a schematic diagram of the overcompression-reverse tension deformation process of a positive conical spring;

[0013] Figure 3 This is a schematic diagram of the overcompression-reverse tension deformation process of an inverted conical spring;

[0014] In the diagram: 1. Helical compression spring; 2. Mass; 3. Damping element; , , These are three markings representing the top coil, a middle coil, and the bottom coil of a conical spring, used to visually illustrate the over-compression and reverse stretching deformation process of a helical compression spring. 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, a low-frequency tuned mass damping device for reverse-stretching a compression spring includes a helical compression spring 1, a mass body 2, and a damping element 3. The specific implementation is illustrated below using two typical cases of vertically placed springs as examples. The specific steps are as follows: the helical compression spring 1 is placed vertically, and its bottom ring is fixed to a suitably sized circular ring. For Figure 2As shown, axial pressure is applied to the top ring to fully compress it until the springs, except for the bottom ring, pass through the middle of the bottom ring to complete the flipping. For Figure 3 As shown, axial pressure is applied to the top of the helical compression spring 1 to fully compress it until all coils except the bottom coil have passed over the bottom coil and completed the flip. For the two typical types of springs mentioned above, after the flip is completed, it is fixed in the flipped state, and the specific fixing method is not limited. Then, the bottom coil of the helical compression spring 1 in the flipped and stretched state is installed on the top plate of the box girder or the top of the box girder's internal support, and the specific connection method is not limited. The suspended helical compression spring 1 (which can be called the reverse helical compression spring 1 at this time) initially has its top coil at the bottom movable end, connected to the mass body 2, suspending the mass body 2. The reverse helical compression spring 1 is used to balance the weight of the mass body 2 and provide stiffness for the vibration system, and the two form a tuning mass device. The original length of the helical compression spring 1 is very large and its stiffness is very small. After reverse stretching, although it occupies very little space, it can bear a large weight of the mass body 2. Within a limited space, the large compression deformation and reverse stretching deformation of the spring are fully realized, while maintaining a basically unchanged low stiffness. Therefore, low-frequency tuning can be achieved. Since the helical compression spring 1 transitions from an initial compressed state to a tensile state during operation, it does not encounter the instability problems faced by traditional compression springs, nor does it require additional lateral contact, resulting in very low damping. A damping element 3 with appropriate parameters can be placed at suitable locations as needed to provide additional damping for the tuned mass damping device, achieving optimal control performance.

[0017] 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 low-frequency tuned mass damping device for reverse stretching of a compression spring, characterized in that, The low-frequency tuned mass damping device includes a helical compression spring (1) and a mass body (2). Place the helical compression spring (1) vertically, horizontally, or at an angle, with the bottom ring fixed on a ring of the corresponding size. Apply pressure to the helical compression spring (1) continuously at the top ring or a local position in the middle until the top ring of the helical compression spring (1) passes through or wraps around the bottom ring and flips over, fixing the helical compression spring (1) in the flipped state. Install the bottom ring of the helical compression spring (1) in the flipped state on the top plate of the box girder or on the top of the box girder's internal support. At this time, the helical compression spring (1) is the reverse helical compression spring (1). The top ring of the helical compression spring (1) is at the lowest movable end and is connected to the mass body (2) for suspending the mass body (2). The reverse helical compression spring (1) is used to balance the gravity of the mass body (2) and provide stiffness. The two form a low-frequency tuned mass damping device.

2. The low-frequency tuned mass damping device according to claim 1, characterized in that, The low-frequency tuned mass damping device also includes a damping element (3) to provide the required damping for the low-frequency tuned mass damping device.

3. The low-frequency tuned mass damping device according to claim 1, characterized in that, The spiral compression spring (1) is made into a gradually tapered or tower-shaped spring.

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