Bridge large-amplitude vibration excitation device

Abstract

This invention belongs to the field of large-scale bridge vibration technology. Addressing the problems of existing large-scale excitation equipment being complex, bulky, expensive, and having a narrow operating frequency range, making it difficult to achieve low-frequency large-amplitude steady-state excitation, this invention provides a bridge large-amplitude vibration excitation device that can rapidly and accurately tune its frequency over a wide frequency band. This makes it possible to excite large-amplitude steady-state vibrations of various low-frequency modes in large-scale bridges. This invention introduces sprocket sets and chains of various diameters into the excitation device, providing a mass-distribution-adjustable inertial-compressive flywheel. While achieving large-amplitude reliable transmission between the oscillator and the inertial compressive strength, it meets the wide-frequency band requirements for bridge field excitation, and provides precise, rapid, and efficient frequency tuning. Furthermore, through a series of structural optimization measures, the size of the excitation device is reduced, making it lightweight, compact, and easy to transport, durable, easy to use, and economical. It can be directly applied to large-amplitude steady-state vibration tests of large-scale bridges and other engineering structures in the field for both vertical and torsional vibration.

Description

Technical Field

[0001] This invention belongs to the field of large bridge vibration technology, and relates to a large-amplitude vibration excitation device for bridges. Specifically, it relates to a device that uses a mass-adjustable flywheel and sprocket group transmission technology to realize wide-frequency large-amplitude vertical vibration excitation of large bridges. Background Technology

[0002] Accurate identification of bridge modal parameters provides a reliable basis for bridge performance evaluation and vibration control. The damping ratio of large bridges is a key parameter affecting wind-induced vibration and seismic response, and is closely related to amplitude. The causes of bridge damping are numerous and complex, and are generally identified through physical dynamic testing methods. Environmentally excited bridge vibrations typically have small responses, low signal-to-noise ratios, and low damping ratio identification accuracy, and cannot extract damping information under large amplitude conditions. Vehicle-borne or tumbling excitation of bridge vibrations also results in small responses and significant dispersion in identification results. In-situ excitation testing is a possible means to obtain large-amplitude vertical and torsional vibrations of long-span bridges. Existing large-scale excitation equipment suffers from drawbacks such as complex structure, bulky equipment, high cost, and narrow operating frequency range, and it is difficult to achieve low-frequency, large-amplitude steady-state excitation.

[0003] Existing bridge vertical or torsional vibration excitation devices include eccentric inertial vibrators, servo hydraulic vibrators, and electric vibrators. Eccentric inertial vibrators are limited by the mass of their eccentric oscillator; at lower frequencies, the vibrator's weight increases dramatically with the required excitation force, reaching hundreds of tons, and is generally only suitable for small to medium-span bridges. While servo hydraulic and electric vibrators can provide wider frequency bands, their excitation force is insufficient at low frequencies, and they can only achieve single-point excitation, making them unsuitable for vibrating large-span, low-frequency bridges.

[0004] Based on the above problems, this invention employs inertial capacitance amplification technology to provide the excitation system with an equivalent mass much larger than its own physical mass, thus achieving frequency reduction. Introducing inertial capacitance can significantly reduce the original length of the spring and the weight of the physical oscillator, making the excitation device smaller and lighter, providing a possible solution to the problems of complex, bulky, expensive, and difficult-to-achieve low-frequency excitation in large bridge excitation equipment. Summary of the Invention

[0005] The purpose of this invention is to develop an economical, convenient, high-precision, low-frequency broadband, and sufficiently large excitation force large-amplitude vibration excitation device for large bridges.

[0006] The technical solution of this invention:

[0007] A bridge large-amplitude vibration excitation device includes a support top plate 1, a support column 2, a support bottom plate 3, a vertical tension spring 4, a vibrator 5, a bearing support 6, a bearing collar 7, a lifting ring 8, a bearing 9, a sprocket assembly 10, a rotating shaft 11, an upper chain 12, an upper tensioner 13, a lower chain 14, a lower tensioner 15, a flywheel inertia capacity 16, a counterweight 17, an actuator 18, and an actuator support 19.

[0008] The support top plate 1, support column 2, and support top plate 3 are connected as a whole by welding, bolting, etc., and stand upright on the bridge deck. The upper end of the vertical tension spring 4 is suspended from the support top plate 1, and the lower end is suspended from the vibrator 5, forming a basic vertical vibration system. Fixed bearing supports 6 are symmetrically set on both sides of the vibrator 5. The bearing collar 7 is connected to the bearing support 6 vertically through the lifting ring 8. The bearing 9 is installed in the bearing collar 7. The sprocket assembly 10 is sleeved on the rotating shaft 11. The rotating shaft 11 passes through the bearing 9. The upper chain 12 is wound around the sprocket assembly 10 half a turn, and the lower end is fixed to it. The upper end is connected to the upper tensioner 13 fixed under the support top plate 1. The lower chain 14 is wound around the sprocket assembly 10 half a turn, and the upper end is fixed to it. The lower end is connected to the support fixed under the support bottom plate 3. The lower tensioner 15 is connected, and the upper chain 12 and the lower chain 14 are wound around the sprocket assembly 3 in opposite directions. The sprocket assembly 10 is symmetrically arranged on both sides of the rotating shaft 11 to ensure that the rotating shaft 11 is subjected to symmetrical force. The flywheel inertia capacity 16 is coaxially and symmetrically installed and fixed on the rotating shaft 11 to provide most of the equivalent mass for the vibration system. Multiple counterweights 17 are temporarily and symmetrically arranged on the flywheel inertia capacity 16 as needed. They can slide freely and their positions are easy to fix, so as to achieve rapid and precise adjustment of the system vibration frequency. Actuator brackets 19 of actuators 18 are symmetrically arranged on both sides of the vibrator 5. The upper end of the actuator 18 is hinged to it, and the lower end is hinged to the bracket base plate 3. The actuator 18 is used to excite the entire system to make vertical vibration, thereby exciting the bridge to make vertical vibration.

[0009] Two sets of large-amplitude bridge vibration excitation devices are symmetrically arranged on both sides of the main beam along the transverse direction of the bridge. Reverse excitation can excite torsional vibration of the bridge. This device is not limited to large-amplitude bridge vibration excitation, but can also be used for other large-scale engineering structures.

[0010] The beneficial effects of this invention are as follows: (1) The introduction of sprocket sets and chains can realize a large-scale reliable transmission between a 10-ton physical mass oscillator and a 100-ton equivalent mass inertia, solving the problems of excessive damping, insufficient stiffness of flexible rope belt transmission, and inefficiency or even failure caused by unstable frequency in traditional rigid transmission methods; (2) Sprocket sets of various diameters can realize various equivalent masses, meeting the needs of a wide frequency range of multiple modes of bridge excitation, which is much more convenient than adjusting the equivalent mass of springs, stiffness, and inertia, greatly improving work efficiency; (3) The equivalent mass of the system can be adjusted very efficiently and quickly by using several small mass counterweights, thereby accurately adjusting the frequency and improving excitation efficiency; (4) The actuator is placed on both sides of the oscillator by using a bracket, which greatly reduces the overall height of the excitation device, making it small in size, light in weight, simple and compact in structure, convenient to transport, and economical; (5) In some cases, manual excitation can be used to replace the actuator, and the overall cost may be lower. Attached Figure Description

[0011] Figure 1 This is a structural diagram of a large-amplitude vibration excitation device for bridges;

[0012] Figure 2 This is a schematic diagram illustrating one method of implementing the mass-adjustable flywheel inertia capacity;

[0013] Figure 3 This is a schematic diagram of a sprocket assembly.

[0014] Figure 4 This is a structural diagram of a bearing support structure;

[0015] In the diagram: 1. Support top plate, 2. Support column, 3. Support bottom plate, 4. Vertical tension spring, 5. Vibrator, 6. Bearing bracket, 7. Bearing collar, 8. Lifting eye, 9. Bearing, 10. Sprocket assembly, 11. Shaft, 12. Upper chain, 13. Upper tensioner, 14. Lower chain, 15. Lower tensioner, 16. Flywheel inertia, 17. Counterweight, 18. Actuator, 19. Actuator bracket. Detailed Implementation

[0016] The specific embodiments of the present invention will be described in detail below with reference to the technical solutions and accompanying drawings.

[0017] like Figure 1As shown, the bridge large-amplitude vibration excitation device includes a support top plate 1, a support column 2, a support bottom plate 3, a vertical tension spring 4, a vibrator 5, a bearing support 6, a bearing collar 7, a lifting ring 8, a bearing 9, a sprocket assembly 10, a rotating shaft 11, an upper chain 12, an upper tensioner 13, a lower chain 14, a lower tensioner 15, a flywheel inertia capacity 16, a counterweight 17, an actuator 18, and an actuator support 19. The support top plate 1, support column 2, and support top plate 3 are erected and fixed on the bridge deck through pre-assembly or on-site assembly. The upper end of the vertical tension spring 4 is suspended below the support top plate 1, and the lower end is suspended from the vibrator 5. Fixed bearing supports 6 are symmetrically set on both sides of the vibrator 5. The bearing collar 7 is connected to the bearing support 6 vertically through the lifting ring 8. The bearing 9 is installed in the bearing collar 7. The sprocket assembly 10 is sleeved on the rotating shaft 11. The rotating shaft 11 passes through the bearing 9. The upper chain 12 is wrapped around the sprocket assembly 10 half a turn, and the lower end is fixed to it. The upper end is connected to the upper tensioner 13 fixed under the support top plate 1. The lower chain 14 is wrapped around the sprocket assembly 10 half a turn, and the upper end is fixed to it. The lower end is connected to the lower tensioner 15 fixed under the support bottom plate 3. The upper chain 12 and the lower chain 14 wind around the sprocket assembly 3 in opposite directions. The sprocket assembly 10 is symmetrically arranged on both sides of the rotating shaft 11, thus ensuring that the rotating shaft 11 is subjected to symmetrical forces. The flywheel inertia capacity 16 is coaxially and symmetrically installed and fixed on the rotating shaft 11, providing most of the equivalent mass for the vibration system. Multiple counterweights 17 are temporarily and symmetrically arranged on the flywheel inertia capacity 16 as needed. They can slide freely and their positions are easy to fix, thus enabling rapid and precise adjustment of the system's vibration frequency. Actuator brackets 19 of actuators 18 are symmetrically arranged on both sides of the vibrator 5. The upper end of the actuator 18 is hinged to the bracket, and the lower end is hinged to the bracket base plate 3. The actuator 18 is used to excite the entire system to make vertical vibrations, thereby exciting the vertical vibration of the bridge. The above scheme involves supporting the flywheel's inertia 16 on the oscillator 5, allowing it to vibrate up and down relative to the bridge during rotation. Alternatively, the flywheel's inertia 16 can be supported by bearing brackets 6 on the top plate 1 / column 2 / base plate 3 of the support, preventing it from vibrating up and down with the oscillator 5 and causing only reciprocating rotation relative to the bridge. By symmetrically arranging the two devices along the transverse direction of the bridge on both sides of the main beam and driving the actuators in opposite directions, torsional vibration of the bridge can be excited. This large-amplitude vibration excitation device is not limited to bridges.

[0018] like Figure 2 The diagram shows a structure of a mass-adjustable flywheel with inertia 16, whose spokes extend from the hub and counterweights 17 are distributed on the spokes. The mass and position of these counterweights can be easily adjusted, thereby achieving convenient, efficient, and precise frequency tuning.

[0019] like Figure 3 The diagram shows a sprocket assembly 10, which may contain sprockets of various sizes, with each size appearing in pairs, thereby facilitating large-scale adjustment of equivalent mass and wide-frequency regulation of vibration.

[0020] like Figure 4 The diagram shows a bearing support structure, including a bearing collar 7 and a lifting ring 8, with a bearing 9 installed inside the bearing collar 7.

[0021] The materials and dimensions of the top plate 1 and bottom plate 3 of the support are not limited, but they have sufficient strength and rigidity, are as lightweight as possible, and are easy to transport. They can be made of materials such as steel plates and aluminum plates, and do not necessarily have to be a single plate. They can also be hollowed out, or made of steel pipes, aluminum pipes, etc. to form a checkerboard grid structure.

[0022] The material, size, and quantity of the support column 2 are not limited, but it has sufficient strength and rigidity, is as lightweight as possible, and is easy to transport. It can be made of steel pipe, aluminum pipe, or profile.

[0023] The material, size, cross-sectional shape, and quantity of the vertical tension spring 4 are not limited, but lightweight, high-strength, and linearly elastically stable materials should be used as much as possible.

[0024] The material, size, mass, and construction of the oscillator 5 are not limited.

[0025] The bearing bracket 6 is not limited in material, size, or form, but has sufficient strength and rigidity.

[0026] The bearing collar 7 has sufficient strength and rigidity, and its inner diameter matches the outer diameter of the bearing 9.

[0027] The material, size, and form of the lifting ring 8 are not limited, but it has sufficient strength and rigidity to facilitate tightening of the bearing collar 7 with the bearing bracket 6.

[0028] The bearing 9 is not limited in material, size, or form, but has sufficient strength and rigidity, minimizes frictional resistance, and has an inner diameter that matches the diameter of the rotating shaft 11.

[0029] The material of the sprocket assembly 10 is not limited, and its size needs to be determined comprehensively in combination with requirements such as frequency, amplitude, and equivalent mass. It is symmetrically arranged on both sides of the rotating shaft 11 and can contain sprockets of various sizes. Each size of sprocket appears in pairs and is connected to the upper chain 12 and the lower chain 14 respectively. Under the condition that other parameters remain unchanged, using sprockets of different diameters can achieve different equivalent masses and vibration frequencies, which is convenient for wide-range frequency tuning. The smaller the diameter, the smaller the allowable amplitude, but the higher the mass amplification factor of the inertial capacitive system.

[0030] The material, diameter, length, and quantity of the shaft 11 are not limited. It is recommended to use steel or aluminum pipes, which should be as lightweight, high-strength, smooth, and wear-resistant as possible. Under the condition of meeting the strength and rigidity requirements, the diameter of the shaft 11 and the inner diameter of the bearing 9 in contact with the bearing should be as small as possible. Under the same amplitude conditions, the rolling friction energy consumption of the bearing is smaller. Therefore, the shaft 11 does not necessarily have to use the same diameter throughout its length.

[0031] The upper chain 12 and lower chain 14 have sufficient strength and rigidity to match the sprocket assembly 10, and are wound adjacently in opposite directions, existing in a vertical plane when stationary. This converts the vertical translation of the oscillator 5 into the rotation of the shaft 11, effectively avoiding the high damping and losses caused by friction or collision in traditional transmission systems (such as gears and toothed plates or ball screws), resulting in higher excitation efficiency, lower cost, and easier maintenance. To ensure the symmetry and stability of the transmission, two pairs of symmetrically arranged chains are required. If the mass, amplitude, and frequency of the oscillator 5 are small, and the tension of the upper chain 12 and lower chain 14 is also small, they can be replaced with strips of sufficient strength, rigidity, and width, directly wound around the shaft 11, and the sprocket assembly can be eliminated.

[0032] The upper tensioner 13 and the lower tensioner 15 shall ensure sufficient strength and rigidity. Their materials, forms and sizes are not limited, so as to facilitate reliable adjustment of the force on the upper chain 12 and the lower chain 14 and keep them in a taut state.

[0033] The flywheel inertia capacity 16 should ensure sufficient strength and rigidity. Its material, form and size are not limited, and should be determined by comprehensively considering factors such as economy, convenience and durability.

[0034] The counterweight 17 is not limited in mass, quantity, or form, and can be freely and conveniently arranged at different positions of the flywheel inertia 16. The implementation method is not limited. It is mainly used for quick, efficient, and precise small-amplitude adjustment of vibration frequency. Due to its larger rotation radius and higher equivalent mass, it is more efficient and faster than adjusting the frequency by adding or subtracting mass on the oscillator 5 and / or changing the spring stiffness.

[0035] The actuator 18 is not limited in form or specification, and is generally arranged symmetrically on both sides of the oscillator 5, as long as it meets the requirements of driving force and amplitude of the inertial capacitive system.

[0036] The material and form of the actuator bracket 19 are not limited, but sufficient strength and rigidity must be ensured. The actuator bracket 19 extends outward on the vibrator 5, which allows the actuator 18 to be placed on the side of the vibrator 5 instead of below it, thereby greatly reducing the height of the bracket column 2, making the vibration system more stable and saving costs.

[0037] Under conditions where the bridge tonnage is not very large, the vibration frequency is not very high, and the amplitude is not very large, the vibration of the system can be excited by manually rotating the flywheel inertia capacity 16 (with a large diameter, which can reach 3m or even larger, and the manual rotation arm is large), thereby eliminating the need for actuator 18 and actuator support 19.

[0038] The flywheel inertia capacity 16 is supported on the top plate 1, column 2 or bottom plate 3 of the support by the bearing bracket 6. It does not vibrate up and down with the vibrator 5 and does not vibrate up and down relative to the bridge, but only rotates back and forth.

[0039] 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 bridge large-amplitude vibration excitation device, characterized in that, The large-amplitude vibration excitation device for the bridge includes a support top plate (1), a support column (2), a support bottom plate (3), a vertical tension spring (4), a vibrator (5), a bearing support (6), a bearing collar (7), a lifting ring (8), a bearing (9), a sprocket assembly (10), a rotating shaft (11), an upper chain (12), an upper tensioner (13), a lower chain (14), a lower tensioner (15), a flywheel inertia capacity (16), an actuator (18), and an actuator support (19). The support top plate (1), support column (2), and support top plate (3) are integrated and stand upright on the bridge deck; the upper end of the vertical tension spring (4) is suspended below the support top plate (1), and the lower end is suspended by the vibrator (5), forming a vertical vibration system; fixed bearing supports (6) are symmetrically set on both sides of the vibrator (5), the bearing collar (7) is connected to the bearing support (6) vertically through the hanging ring (8), the bearing (9) is installed in the bearing collar (7), the sprocket assembly (10) is sleeved on the rotating shaft (11), and the two ends of the rotating shaft (11) pass through the bearing (9) respectively; the upper chain (12) is wrapped around the sprocket assembly (10) half a turn, the lower end is fixed to the sprocket assembly (10), and the upper end is fixed to the sprocket assembly (10). The upper tensioner (13) is fixed under the top plate (1) of the support; the lower chain (14) is wound around the sprocket assembly (10) half a turn, the upper end is fixed to the sprocket assembly (10), and the lower end is connected to the lower tensioner (15) fixed under the bottom plate (3) of the support; the flywheel inertia (16) is coaxially and symmetrically installed and fixed at the end of the rotating shaft (11) to provide most of the equivalent mass for the vibration system; the actuator brackets (19) of the actuator (18) are symmetrically arranged on both sides of the oscillator (5), the upper end of the actuator (18) is hinged to it, and the lower end is hinged to the bottom plate (3) of the support. The actuator (18) is used to excite the entire system to make vertical vibration, and then excite the bridge to make vertical vibration.

2. The bridge large-amplitude vibration excitation device according to claim 1, characterized in that, As needed, multiple counterweights (17) are symmetrically arranged on the flywheel inertia (16).

3. The bridge large-amplitude vibration excitation device according to claim 1, characterized in that, The inner diameter of the bearing collar (7) matches the outer diameter of the bearing (9).

4. The bridge large-amplitude vibration excitation device according to claim 1, characterized in that, The inner diameter of the bearing (9) matches the diameter of the shaft (11).

5. The bridge large-amplitude vibration excitation device according to claim 1, characterized in that, The upper chain (12) and the lower chain (14) are wound around the sprocket assembly (3) in opposite directions. In a static state, they are in a vertical plane, converting the up-and-down translation of the oscillator (5) into the rotation of the shaft (11). The sprocket assembly (10) is symmetrically arranged on both sides of the shaft (11) to ensure that the shaft (11) is subjected to symmetrical forces.

6. The bridge large-amplitude vibration excitation device according to claim 1, characterized in that, The diameter of the shaft (11) in contact with the bearing (9) and the inner diameter of the bearing (9) should be as small as possible, and the overall diameter of the shaft (11) may be the same or different.

7. The bridge large-amplitude vibration excitation device according to claim 1, characterized in that, The actuator bracket (19) extends outward on the oscillator (5), allowing the actuator (18) to be placed on the side of the oscillator (5).

8. The bridge large-amplitude vibration excitation device according to claim 1, characterized in that, The flywheel inertia (16) is supported by the bearing bracket (6) on the top plate (1), column (2) or bottom plate (3) of the bracket. It does not vibrate up and down with the vibrator (5) and does not vibrate up and down relative to the bridge, but only rotates back and forth.

9. The bridge large-amplitude vibration excitation device according to claim 1, characterized in that, The bridge can be excited to produce large-amplitude vibrations by artificial excitation, and the actuator (18) and actuator support (19) are eliminated.

10. The bridge large-amplitude vibration excitation device according to claim 1, characterized in that, Two sets of large-amplitude bridge vibration excitation devices are symmetrically arranged on both sides of the main beam along the transverse direction of the bridge. Reverse excitation can excite the torsional vibration of the bridge.

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