A tuned damper for air track girder vortex vibration control and air track

Abstract

This invention relates to a tuned damper and a monorail for controlling vortex-induced vibration of a monorail main beam. The damper includes a damping box, a mass block assembly, a spring, a guide shaft, a guide assembly, and damping fluid. One end of the spring is connected to the bottom of the damping box cavity, and the other end is connected to the bottom of the mass block assembly. One end of the guide shaft is connected to the bottom of the damping box cavity, and the other end is connected to the top of the damping box cavity, passing through the mass block assembly. The guide assembly is fixedly connected to the mass block assembly and symmetrically arranged on both sides of the guide shaft. The damping fluid is disposed within the damping box cavity. The advantages of this invention are: 1. By limiting lateral displacement through the guide assembly, stability is increased; 2. Adjusting the base allows for adjustment of the gap between the roller and the guide shaft without affecting the vertical vibration of the mass block assembly, thus promoting stable and long-term operation of the device; 3. The mass block assembly optimizes the adjustment efficiency.

Description

Technical Field

[0001] This invention relates to the field of rail transit technology, and in particular to a tuned damper for controlling vortex vibration of the main beam of a monorail and the monorail itself. Background Technology

[0002] With the rapid development of urban rail transit, monorails have become increasingly popular due to their advantages, such as not occupying road rights, low cost, short construction period, strong environmental adaptability, good landscape effect, and no gas emissions. Monorails, also known as suspended monorail trains, differ from traditional modes of transportation in that their tracks are supported in the air by steel structural columns.

[0003] The monorail track beam is characterized by its large span, light weight, and low damping. Due to its high elevation, it is prone to vortex-induced resonance under wind loads. Wind-induced vortex-induced resonance requires the gradual accumulation of energy to increase the amplitude of the main beam. Since the monorail has a short passage time, vibration reduction measures are only needed to control the vibration of the main beam when there are no vehicles, ensuring that vortex-induced resonance does not occur before a vehicle passes. Wind dynamic tests show that increasing the damping ratio of the structure can effectively suppress vortex-induced resonance; adding a tuned damper is an effective method.

[0004] The natural frequency of the track beam in a monorail can be as low as 0.8 Hz, which is relatively low. Conventional TMD dampers are insufficient to meet the requirements due to excessive static compression of the springs. Chinese patent CN201610223224.8 proposes a vertical fluid-structure interaction tuned mass damper, which can reduce the frequency of the damper under the action of the liquid added mass of the damping oil. However, it still has some problems in low-frequency applications: 1) The setting of the upper and lower springs disperses the stiffness of the springs, making the stiffness of each spring smaller, resulting in poor system stability. During the up and down movement of the mass, the springs are prone to lateral bending and loss of stability; 2) Adjusting the damper parameters requires reprocessing the mass or springs, which can easily lead to material waste. Summary of the Invention

[0005] This invention provides a tuned damper and an air track for controlling vortex vibration of the main beam of an air track, which can solve the problems of 1. poor stability of traditional damper systems and 2. easy material waste in related technologies.

[0006] On one hand, embodiments of the present invention provide a tuned damper for vortex vibration control of a solid track main beam.

[0007] The device includes a damping box, a mass block assembly, a spring, a guide shaft, a guide assembly, and a damping fluid. One end of the spring is connected to the bottom of the inner cavity of the damping box, and the other end is connected to the bottom of the mass block assembly. One end of the guide shaft is connected to the bottom of the inner cavity of the damping box, and the other end is connected to the top of the inner cavity of the damping box, and passes through the mass block assembly. The guide assembly is fixedly connected to the mass block assembly and is symmetrically arranged on both sides of the guide shaft. The damping fluid is disposed in the inner cavity of the damping box.

[0008] In some embodiments, the mass block assembly includes a bottom mass block and multiple side mass plates fixedly connected to both sides, and multiple flow holes are provided through the bottom mass block and the side mass plates.

[0009] In some embodiments, the guide assembly includes a base symmetrically disposed on both sides of the guide shaft and fixed to the side mass plate by a screw. A roller is connected to the base and the roller is tactilely connected to the guide shaft.

[0010] In some embodiments, a baffle is further included, the baffle being U-shaped and snapped between the base and the side mass plate, for adjusting the size between the flow hole and the guide shaft.

[0011] In some embodiments, the guide shaft is disposed on the central axis of the spring and the flow hole.

[0012] In some embodiments, one end of the spring is connected to the bottom of the damping box cavity, and the other end is connected to the bottom mass block.

[0013] In some embodiments, the bottom mass block has an inverted V-shaped cross-section, and multiple intermediate mass plates are fixedly connected to the recess of the inverted V-shaped bottom mass block.

[0014] On one hand, embodiments of the present invention provide an air track, including the tuned damper described above.

[0015] In some embodiments, the tuned damper is provided with a fixing hole.

[0016] In some embodiments, an empty track is included, a connector is welded onto the empty track, a screw is provided on the connector, and the tuned damper is fixedly connected to the connector through the fixing hole.

[0017] The beneficial effects of the technical solution provided by this invention include:

[0018] 1. By limiting lateral offset through guide components, stability is increased;

[0019] 2. By adjusting the base, the gap between the roller and the guide shaft can be adjusted, which will not affect the vertical vibration of the mass block assembly and is conducive to the stable and long-term operation of the device.

[0020] 3. The frequency of the damper can be changed by increasing or decreasing the number of side mass plates and middle mass plates, making the operation more standardized and reasonable, and avoiding material waste.

[0021] 4. By adjusting the position of the baffle, the flow rate of the damping fluid in the flow hole during the up-and-down movement of the mass block assembly can be adjusted, thereby adjusting the damping ratio of the damper, making the adjustment more convenient and precise.

[0022] 5. The structure of this application does not require replacing the spring to change the stiffness, thus reducing unnecessary waste;

[0023] 6. This application is reasonably designed, easy to adjust, reduces material waste, and is conducive to its widespread promotion. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is one of the structural schematic diagrams of a tuned damper for vortex vibration control of a main beam of an air rail according to the present invention;

[0026] Figure 2 This is an enlarged view of point A of a tuned damper for vortex vibration control of a main beam of an air rail according to the present invention.

[0027] Figure 3 This is the second schematic diagram of a tuned damper for vortex vibration control of a main beam of an air rail according to the present invention.

[0028] Figure 4 This is an enlarged view of section B of a tuned damper for vortex vibration control of a main beam of an air rail according to the present invention.

[0029] Figure 5 This is an enlarged view of the bottom mass block of a tuned damper for vortex vibration control of a main beam of an air rail according to the present invention.

[0030] Figure 6 A cross-sectional view of a tuned damper for vortex vibration control of a main beam of an air rail system according to the present invention.

[0031] Figure 7 This is a schematic diagram of one embodiment of a tuned damper for vortex vibration control of a main beam of an air rail according to the present invention.

[0032] Figure 8 This is a schematic diagram of the overall structure of an air track according to the present invention;

[0033] Figure 9 This is a schematic diagram of the assembly of a tuned damper and connecting parts for an empty track according to the present invention.

[0034] In the diagram: 1. Damping box; 2. Mass block assembly; 21. Bottom mass block; 22. Side mass plate; 23. Middle mass plate; 24. Flow hole; 3. Spring; 4. Guide shaft; 5. Guide assembly; 51. Base; 52. Roller; 6. Damping fluid; 7. Baffle; 8. Tuned damper; 81. Fixing hole; 9. Empty rail; 91. Connector. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] See Figures 1 to 6 As shown, this embodiment of the invention provides a tuned damper for vortex vibration control of a solid track main beam, including a damping box 1 and a mass block assembly 2.

[0037] Spring 3 has one end connected to the bottom of the inner cavity of the damping box 1 and the other end connected to the bottom of the mass block assembly 2;

[0038] The guide shaft 4 is connected at one end to the bottom of the inner cavity of the damping box 1 and at the other end to the top of the inner cavity of the damping box 1, and passes through the mass block assembly 2.

[0039] The guide assembly 5 is fixedly connected to the mass block assembly 2 and is symmetrically arranged on both sides of the guide shaft 4;

[0040] Damping fluid 6 is disposed in the inner cavity of the damping box 1.

[0041] In this embodiment, damping fluid 6 is added to the inner cavity of the damping box 1, and the mass block assembly 2 is immersed in the damping fluid 6. The amount of damping fluid 6 can be increased or decreased according to actual needs.

[0042] Meanwhile, in the existing technology, the vibration frequency of the damper can be reduced by the liquid added mass of the damping oil. However, there are still some problems in the application of low frequency scenarios: 1) The setting of the upper and lower springs disperses the stiffness of the springs, making the stiffness of each spring smaller, resulting in poor system stability. During the up and down movement of the mass block, the spring is prone to lateral bending and loss of stability; 2) Adjusting the parameters of the damper requires reprocessing the mass block or springs, which can easily lead to material waste.

[0043] In this design, one end of the guide shaft 4 is connected to the bottom of the inner cavity of the damping box 1, and the other end is connected to the top of the inner cavity of the damping box 1, and passes through the mass block assembly 2; the guide assembly 5 is fixedly installed on the mass block assembly 2, and the guide assembly 5 is symmetrically arranged on both sides of the guide shaft 4 under the action of the guide assembly 5. Therefore, the mass block assembly 2 can stably move up and down under the action of the guide assembly 5, and there will be no lateral movement during the up and down movement.

[0044] Optionally, the mass block assembly 2 includes a bottom mass block 21 and multiple side mass plates 22 fixedly connected to both sides. Multiple flow holes 24 are provided through the bottom mass block 21 and the side mass plates 22.

[0045] Optionally, the guide shaft 4 is located on the central axis of the spring 3 and the flow hole 24.

[0046] Optionally, one end of the spring 3 is connected to the bottom of the inner cavity of the damping box 1, and the other end is connected to the bottom mass block 21.

[0047] Optionally, the bottom mass block 21 has an inverted V-shaped cross section, and multiple intermediate mass plates 23 are fixedly connected to the recess of the inverted V-shaped bottom mass block 21.

[0048] In this embodiment, by providing flow holes 24 through the bottom mass block 21 and the side mass plate 22 in an inverted V shape, and placing the guide shaft 4 inside the flow holes 24, the damping fluid 6 flows in the flow holes 24 of the bottom mass block 21 and the side mass plate 22 during low-frequency vibration, thereby realizing the adjustment of the damping ratio ξ.

[0049] Meanwhile, the difference from existing technologies lies in the following: Existing technologies require S01. Determining the mass m of the moving mass block, the target frequency f, and the target damping ratio ξ in the ultra-low frequency liquid mass tuned damper based on the vibration reduction target; S02. Determining the static deformation δ of the spring based on the amplitude and allowable space of the ultra-low frequency liquid mass tuned damper; S03. Preliminarily determining the shape of the mass block based on the target damping ratio ξ; S04. Experimentally determining the additional liquid mass δm based on the shape of the mass block and the frequency f; S05. Applying the formula k=(2πf) 2. Determine the stiffness k of the spring assembly using (m + δm); S06. Determine the equivalent density of the mass block using the formula m·g=ρ·g·V+k·δ; S07. Measure the frequency of the damper. If the deviation is large, adjust it by changing the spring stiffness k. If the deviation is small, adjust it by changing the mass or equivalent density of the mass block to ensure that the frequency f and the static deformation δ of the spring meet the requirements; S08. Measure the damping ratio of the damper. If there is a deviation, adjust the damping ratio by changing the shape or gap of the mass block; S09. Repeat S07 and S08 until both the frequency and the damping ratio meet the requirements.

[0050] Compared with existing technologies, this embodiment of the solution has a wider range of damping ratio adjustment and is more practical.

[0051] In this embodiment, through holes are provided on both sides and in the recess of the inverted V-shaped bottom mass block 21. Through holes are also provided on multiple side mass plates 22 and multiple middle mass plates 23. During installation, the center of the through holes on the multiple middle mass plates 23 is aligned with the center of the through holes in the recess of the inverted V-shaped bottom mass block 21, and the multiple middle mass plates 23 are fixed to the inverted V-shaped bottom mass block 21 with bolts. Similarly, the center of the through holes on the multiple side mass plates 22 is aligned with the center of the through holes on both sides of the inverted V-shaped bottom mass block 21, and the multiple side mass plates 22 are fixed to both sides of the inverted V-shaped bottom mass block 21 with bolts.

[0052] Meanwhile, in the existing technology, adjusting the damping ratio by changing the stiffness of the spring, or by changing the shape or gap of the entire mass block, has the following problems: 1. Replacing the spring stiffness is costly; 2. Changing the shape of the entire mass block means replacing the entire mass block, increasing costs. This application, however, can adjust the frequency by changing the number of side mass plates 22 or the middle mass plates 23, which not only saves costs but also improves work efficiency.

[0053] Optionally, the guide assembly 5 includes a base 51, which is symmetrically arranged on both sides of the guide shaft 4 and fixed to the side mass plate 22 by screws. A roller 52 is connected to the base 51, and the roller 52 is tactilely connected to the guide shaft 4.

[0054] Optionally, a baffle 7 is also included. The baffle 7 is U-shaped and is snapped between the base 51 and the side mass plate 22 for adjusting the size between the flow hole 24 and the guide shaft 4.

[0055] In this embodiment, the baffle 7 is snapped between the base 51 and the side mass plate 22. When it is necessary to adjust the flow of the damping fluid 6 at the flow hole 24 to adjust the damping ratio ξ, first loosen the screw, move the base 51 away from the side mass plate 22, and then the baffle 7 can move along the direction of the notch. Adjust the baffle 7 to a suitable position, then tighten the screw, and the base 51 and the side mass plate 22 will snap the baffle 7 in place, thereby completing the adjustment of the damping ratio ξ.

[0056] In another embodiment of this solution, the guide shaft 4 and spring 3 are configured as three groups, see [reference]. Figure 7 As shown, the bottom mass block 21 in the shape of an inverted "V" has one flow hole 24 on one side and two flow holes 24 on the other side. Correspondingly, one flow hole 24 is provided on one side mass plate 22 and two flow holes 24 are provided on the other side mass plate 22. Three guide shafts 4 are provided inside the damping box 1. One end of the three guide shafts 4 is fixed to the bottom of the inner cavity of the damping box 1 and the other end is fixed to the top of the inner cavity of the damping box 1. The guide shafts 4 pass through the flow holes 24. A pair of guide components 5 and baffles 7 are fixed on one side mass plate 22. The guide components 5 and baffles 7 are symmetrically arranged on both sides of the guide shafts 4. Two pairs of guide components 5 and baffles 7 are fixed on the other side mass plate 22. The above method can be used when the vertical vibration is small, thereby saving materials.

[0057] In another embodiment of this solution, the guide shaft 4 and spring 3 are set to four or more groups, and guide components 5 are symmetrically arranged on both sides of each guide shaft 4. This method can be used when there is a large vertical vibration. The number of components can be increased or decreased according to actual needs, thereby saving materials.

[0058] In this embodiment, to ensure that the mass block assembly 2 does not shift in the horizontal direction during its up-and-down movement, this solution can provide multiple options according to actual needs, such as appropriately increasing the spring 3, guide shaft 4, guide assembly 5, and baffle 7 to further ensure horizontal stability.

[0059] See Figures 8 to 9 As shown, in one aspect, an embodiment of the present invention provides an air track, including the above-mentioned tuned damper 8.

[0060] Optionally, the tuned damper 8 is provided with a fixing hole 81.

[0061] Optionally, it includes an empty track 9, on which a connector 91 is welded, and a screw is provided on the connector 91. The tuned damper 8 is fixedly connected to the connector 91 through the fixing hole 81.

[0062] In this embodiment, a fixing hole 11 is provided on the damping box 1 of the tuned damper 8, and a screw is provided on the connector 91. The fixing hole 11 and the fixing position of the screw are aligned, and the tuned damper 8 is fixed on the connector 91 by the screw and the fixing hole 11.

[0063] In one embodiment of this scheme, a monorail track beam, after finite element analysis, is prone to vortex-induced vibration in its first-order vertical bending mode under wind load. The natural frequency is 0.93Hz, and the modal mass is 450t. Based on preliminary selection of damper parameters, eight tuned dampers (8) are installed for vortex vibration control of the monorail main beam. Each damper has a moving mass m1 = 562.5kg, a damper frequency f1 = 0.93Hz, and an optimal damping ratio ζ = 6.1%. After the track beam is erected, actual measurements show a deviation between the first-order vertical bending frequency and the finite element calculation result, at f2 = 0.90Hz. To ensure the damping effect of the dampers, the frequency deviation between the dampers and the structure being damped should not exceed 1%. Therefore, the damper parameters need to be adjusted. According to the formula...

[0064]

[0065] The final determined active mass of the damper was m² = 587.5 kg, an increase of 25 kg from the original mass. Frequency adjustment was achieved by adding two 12.5 kg mass plates. The measured damping ratio of the damper was 7.5%, which is greater than the optimal damping ratio. By adjusting the position of the baffle to increase the flow area of ​​the flow orifice, the damping ratio was reduced to 6.1%, thus completing the damping ratio adjustment. Testing showed that the damper exhibits excellent stability and robustness during operation, preventing yaw and instability during vibration and effectively suppressing track beam vibration.

[0066] The beneficial effects of this invention are as follows:

[0067] 1. By limiting lateral offset through guide components, stability is increased;

[0068] 2. By adjusting the base, the gap between the roller and the guide shaft can be adjusted, which will not affect the vertical vibration of the mass block assembly and is conducive to the stable and long-term operation of the device.

[0069] 3. The frequency of the damper can be changed by increasing or decreasing the number of side mass plates and middle mass plates, making the operation more standardized and reasonable, and avoiding material waste.

[0070] 4. By adjusting the position of the baffle, the flow rate of the damping fluid in the flow hole during the up-and-down movement of the mass block assembly can be adjusted, thereby adjusting the damping ratio of the damper, making the adjustment more convenient and precise.

[0071] 5. The structure of this application does not require replacing the spring to change the stiffness, thus reducing unnecessary waste;

[0072] 6. This application is reasonably designed, easy to adjust, reduces material waste, and is conducive to its widespread promotion.

[0073] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0074] It should be noted that, in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising," or any other variation thereof, is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0075] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A tuned damper for controlling vortex-induced vibration of a main beam in a monorail system, characterized in that, It includes a damping box (1) and a mass block assembly (2). The spring (3) is connected at one end to the bottom of the inner cavity of the damping box (1) and at the other end to the bottom of the mass block assembly (2); The guide shaft (4) is connected at one end to the bottom of the inner cavity of the damping box (1) and at the other end to the top of the inner cavity of the damping box (1), and passes through the mass block assembly (2). The guide assembly (5) is fixedly connected to the mass block assembly (2) and is symmetrically arranged on both sides of the guide shaft (4); Damping fluid (6) is disposed in the inner cavity of the damping box (1); The mass block assembly (2) includes a bottom mass block (21) and multiple side mass plates (22) fixedly connected to both sides. Multiple flow holes (24) are provided through the bottom mass block (21) and the side mass plates (22). The bottom mass block (21) has an inverted V-shaped cross section, and multiple intermediate mass plates (23) are fixedly connected to the recess of the inverted V-shaped bottom mass block (21). The guide assembly (5) includes a base (51), which is symmetrically arranged on both sides of the guide shaft (4) and fixed on the side mass plate (22) by screws. A roller (52) is connected to the base (51), and the roller (52) is tactilely connected to the guide shaft (4). It also includes a baffle (7), which is U-shaped and is snapped between the base (51) and the side mass plate (22) for adjusting the size between the flow hole (24) and the guide shaft (4).

2. A tuned damper for vortex vibration control of a solid track main beam as described in claim 1, characterized in that, The guide shaft (4) is located on the central axis of the spring (3) and the flow hole (24).

3. A tuned damper for vortex vibration control of a solid track main beam as described in claim 1, characterized in that, One end of the spring (3) is connected to the bottom of the inner cavity of the damping box (1), and the other end is connected to the bottom mass block (21).

4. An empty track, characterized in that, Includes the tuned damper (8) as described in any one of claims 1 to 3.

5. The air track as described in claim 4, characterized in that, The tuned damper (8) is provided with a fixing hole (81).

6. The air track as described in claim 5, characterized in that, Includes an empty track (9), on which a connector (91) is welded, and a screw is provided on the connector (91). The tuned damper (8) is fixedly connected to the connector (91) through the fixing hole (81).

Images