Multi-stage negative stiffness-damping system suitable for vibration control of stay cable of real bridge

Abstract

The invention relates to the field of real bridge stay cable vibration reduction control, in particular to a multi-stage negative stiffness-damping system suitable for real bridge stay cable vibration control, which comprises a first hoop fixed on a stay cable, and a damper and a dowel bar connected with the first hoop; a fan-shaped connecting plate is arranged at the bottom of the first hoop, the dampers are symmetrically hinged to connecting holes in the two sides of the fan-shaped connecting plate, and the upper end of the dowel bar is hinged to a connecting hole in the center of the fan-shaped connecting plate; the multi-stage negative stiffness subsystem comprises at least one stage of negative stiffness subsystem with a pre-pressing spring device, and the negative stiffness subsystems are arranged in a layered mode in the axial direction of the dowel bar. The multi-stage negative stiffness subsystem is innovatively designed, multi-stage adjustment of the negative stiffness coefficient is achieved, then effective control over multi-mode vibration of the stay cable is achieved, the three-hole-site design of the fan-shaped connecting plate at the bottom of the first hoop supports symmetrical hinge joint of the damper, and synchronous control over vibration inside and outside the surface of the stay cable is effectively achieved.

Description

Technical Field

[0001] The present invention relates to the field of vibration reduction control of stay cables of real bridges, and in particular to a multi-stage negative stiffness-damping system suitable for vibration control of stay cables of real bridges. Background Art

[0002] Cables are the core load-bearing components of cable-stayed bridges and cable-stayed-suspension bridges. With the continuous increase in the span of cable-stayed bridges, the use of ultra-long cables is becoming increasingly widespread. However, these cables also face significant challenges in dynamic load response. Typical examples include the Ma'anshan Highway-Railway Dual-Use Cable-Stayed Bridge and the Sutong Second Cross-River Channel, both of which have cables exceeding 650 meters in length. These ultra-long cables are susceptible to various harmful vibrations, such as wind-rain vibration and multi-modal high-order vortex vibration, under the influence of wind. These vibrations not only exacerbate fatigue damage in the cables, shortening their service life and posing a serious threat to the safe service and normal operation of the bridge, but also cause discomfort and insecurity for pedestrians and vehicles passing by, potentially attracting widespread public concern. Therefore, effective vibration reduction measures are essential to control the harmful vibrations of ultra-long cables.

[0003] Installing dampers at the anchorage ends near the beams of stay cables is an important means of controlling wind-rain and high-order vortex-induced vibrations in extremely long cables. However, traditional viscous dampers, due to installation height limitations, struggle to provide the required additional damping for the multimodal vibrations of extremely long cables. Recent theoretical and experimental studies have demonstrated that negative stiffness dampers can significantly enhance the effectiveness of viscous dampers in controlling both single-mode and multimodal vibrations in stay cables. Therefore, developing more efficient and practical negative stiffness dampers for stay cables has become an important research direction for controlling cable vibrations.

[0004] Although some patents, such as Patent Application No. 2014103999135 (Magnetic Negative Stiffness Damper) and Patent Application No. 2021104308365 (Magnetic Negative Stiffness Damper for Cable Vibration Isolation Device and Design Method), propose magnetic negative stiffness dampers based on the force of permanent magnets to enhance the vibration damping effect of cable stays, these solutions utilize relatively limited negative stiffness generated by the force of permanent magnets. To meet the negative stiffness requirements for cable vibration reduction, these dampers require a large number of permanent magnet groups, resulting in large dampers and a significant impact on the aesthetics of the bridge. Patent Application No. 2015100599949 (A Passive Spring-Damper Negative Stiffness Damper for Cable Vibration Isolation) proposes utilizing the negative stiffness effect of preloaded coil springs to improve cable control, but its negative stiffness is directly connected in series with the damper, making it difficult to achieve synchronous control of the cable's in-plane and out-of-plane vibrations. Furthermore, the negative stiffness coefficient of this solution cannot be adjusted, and the stiffness of the coil spring is relatively low, making it difficult to meet the negative stiffness coefficient required for actual bridge stay cables. Therefore, it is urgent to develop a multi-stage negative stiffness-damping system suitable for vibration control of actual bridge stay cables to address these technical issues and achieve effective vibration control of actual bridge stay cables, especially ultra-long ones. Summary of the Invention

[0005] In order to solve the problems of limited negative stiffness, excessive size, inability to adjust the stiffness coefficient, and difficulty in achieving synchronous control of in-plane and out-of-plane vibrations in existing negative stiffness dampers, the present invention proposes a multi-stage negative stiffness-damping system suitable for vibration control of real bridge cable-stayed cables. Through the pre-compression and pre-spring device set in the multi-stage negative stiffness subsystem, a negative stiffness effect of amplifying the damper displacement is formed. The number of stages can be increased or decreased according to the vibration reduction requirements of the real bridge cable-stayed cables, thereby realizing dynamic adjustment of the damper amplification factor. Compared with traditional dampers, the installation height and damping coefficient are reduced.

[0006] In order to achieve the above object, the technical solution of the present invention is: A multi-stage negative stiffness-damping system suitable for vibration control of stay cables of real bridges, comprising a first clamp for fixing on the stay cables, and a damper and a force transmission rod connected to the first clamp; The first hoop is provided with a fan-shaped connecting plate at the bottom, and the fan-shaped connecting plate has a plurality of equally spaced connecting holes distributed along the arc direction. The damper is symmetrically hinged to the connecting holes on both sides of the fan-shaped connecting plate, and the upper end of the force transmission rod is hinged to the connecting hole in the center of the fan-shaped connecting plate. It also includes a Y-shaped bracket and a multi-stage negative stiffness subsystem. The Y-shaped bracket is hinged to the damper. The multi-stage negative stiffness subsystem includes at least one stage of negative stiffness subsystem with a pre-stressed spring device arranged in layers along the axial direction of the force transmission rod. The number of stages of the multi-stage negative stiffness subsystem is adjusted according to the vibration reduction requirements of the actual bridge's inclined cable. By setting up the above structure, the vibration of the inclined cable is transmitted to the two symmetrical dampers and the force transmission rod respectively through the first clamp. The force transmission rod 4 transmits the vibration to the multi-stage negative stiffness subsystem. The direction of the resultant elastic restoring force generated by the pre-stressed pre-spring device in the multi-stage negative stiffness subsystem is the same as that of the force transmission rod, forming a negative stiffness effect that amplifies the displacement of the damper piston. Furthermore, each level of the negative stiffness subsystem includes a connecting arm and two pre-stressed spring devices located on both sides of the force transmission rod. The middle part of the connecting arm is fixed on the force transmission rod, and the two ends of the pre-stressed spring device are respectively hinged to the connecting arm and the Y-shaped bracket.

[0007] Furthermore, the preload spring device includes a base and a sleeve connected to the base. The sleeve houses a disc spring guide shaft and a disc spring assembly. The sleeve is hollow and open at both ends. A diaphragm is located within the sleeve. The diaphragm has a center hole. A linear bearing is located on one side of the diaphragm. The disc spring guide shaft passes through the disc spring assembly, the center hole of the diaphragm, and the inner ring of the linear bearing in sequence. The center hole of the diaphragm constrains radial displacement of the disc spring guide shaft.

[0008] Furthermore, the base and sleeve are fixedly connected by a second bolt group. The portion of the disc spring guide shaft extending outside the sleeve is provided with a flange. The base and the disc spring guide shaft flange are fixedly connected by a third bolt group. The ends of the disc spring group respectively abut the diaphragm and the disc spring guide shaft flanges. After installation, the third bolt group of the preload spring device is removed, and the disc spring group releases the preload, causing the system to enter a negative stiffness operating mode.

[0009] Furthermore, the connecting arm is hingedly connected to the base at both ends and includes a first connecting arm, a second connecting arm, and a first bolt assembly. The first connecting arm has an inner surface, and the second connecting arm matches the first connecting arm and has an inner surface. The inner surface of the second connecting arm is opposite to and engages with the inner surface of the first connecting arm. The first bolt assembly passes through corresponding holes in the first and second connecting arms to securely connect the engaged first and second connecting arms to the dowel rod. The connecting arm adopts a split structure to support on-site assembly without disassembling the dowel rod.

[0010] Furthermore, the Y-shaped bracket includes a column and two arms forming a fork. Pairs of second clamps are mounted on the two arms of the Y-shaped bracket. The number of pairs of second clamps matches the number of stages in the multi-stage negative stiffness subsystem. The portion of the disc spring guide shaft extending outside the sleeve is hingedly connected to the second clamps. This structure allows the preload spring device to be hingedly connected to the connecting arms and the Y-shaped bracket at both ends.

[0011] Through the above technical solution, the beneficial effects of the present invention are: Some parts are connected by bolts or pins, which is convenient for on-site assembly and has broad engineering application prospects.

[0012] 1. The present invention provides a multi-stage negative stiffness-damping system suitable for vibration control of stay cables in real bridges. It utilizes the high stiffness and excellent fatigue performance of the disc spring group and innovatively designs a multi-stage negative stiffness subsystem to achieve multi-stage adjustment of the negative stiffness coefficient, thereby being able to adapt to the differentiated requirements of the negative stiffness coefficient for stay cables of different lengths.

[0013] 2. Compared with traditional dampers, this invention offers significant advantages: First, it reduces the installation height and damping coefficient. The multi-stage negative stiffness subsystem effectively reduces the required installation height and damping coefficient of the damper. Second, the overall system structure is simpler, improving the aesthetics of the cable-damper system while reducing the manufacturing cost of the damper. Furthermore, the multi-stage negative stiffness subsystem amplifies the damper's displacement, improving the damper's control of the cable's multimodal vibrations and effectively widening its control frequency band. Furthermore, the preload spring devices symmetrically arranged on both sides of the force transmission rod avoid instability caused by asymmetric force, ensuring the efficient implementation of the negative stiffness effect.

[0014] 3. The multi-stage negative stiffness subsystem of the present invention has a compact structure, and each part is connected by bolts or pins, which is convenient for on-site assembly and has broad engineering application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of the multi-stage negative stiffness-damping system applicable to vibration control of the stay cables of a real bridge according to the present invention; Figure 2 This is a right side view of the structure of the multi-stage negative stiffness-damping system applicable to vibration control of stay cables of a real bridge according to the present invention; Figure 3 Schematic diagram of the first clamp in the multi-stage negative stiffness-damping system applicable to vibration control of stay cables of a real bridge according to the present invention; Figure 4 Schematic diagram of a connecting arm in a multi-stage negative stiffness-damping system applicable to vibration control of stay cables of a real bridge according to the present invention; Figure 5This is a schematic diagram of a pre-stressed spring device before pre-stressing in a multi-stage negative stiffness-damping system applicable to vibration control of stay cables of a real bridge according to the present invention; Figure 6 This is a schematic diagram of a pre-stressed spring device in a multi-stage negative stiffness-damping system suitable for vibration control of stay cables of a real bridge according to the present invention; Figure 7 Schematic diagram of the interior of the sleeve in the multi-stage negative stiffness-damping system applicable to vibration control of stay cables of a real bridge according to the present invention; Figure 8 This is a schematic diagram of the distribution of the second clamp on the Y-shaped bracket in the multi-stage negative stiffness-damping system suitable for vibration control of the inclined cables of a real bridge according to the present invention.

[0016] The reference numerals in the accompanying drawings are: 1. Stay cable; 2. First clamp; 3. Damper; 4. Force transmission rod; 5. Connecting arm; 501. First connecting arm; 502. Second connecting arm; 503. First bolt group; 6. Preload spring device; 601. Base; 602. Sleeve; 603. Partition; 604. Second bolt group, 605. Linear bearing; 606. Disc spring guide shaft; 607. Disc spring group; 608. Third bolt group; 7. Y-shaped bracket; 701. Second clamp. DETAILED DESCRIPTION

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: like Figures 1-8 As shown, this embodiment provides a multi-stage negative stiffness-damping system suitable for vibration control of a real bridge cable-stayed cable, comprising a first clamp 2 for fixing on the cable-stayed cable 1 and a damper 3 and a force transmission rod 4 connected to the first clamp 2; wherein, a fan-shaped connecting plate is provided at the bottom of the first clamp 2, and the fan-shaped connecting plate has three equally spaced connecting holes distributed along the arc direction, the damper 3 is symmetrically hinged to the connecting holes on both sides of the fan-shaped connecting plate, and the upper end of the force transmission rod 4 is hinged to the connecting hole in the center of the fan-shaped connecting plate; it also includes a Y-shaped bracket 7 and a multi-stage negative stiffness subsystem, the Y-shaped bracket 7 and the damper 3 are hinged, and the multi-stage negative stiffness subsystem includes at least one stage of negative stiffness subsystem with a pre-stressed spring device 6 arranged in layers along the axial direction of the force transmission rod 4, and the number of stages of the multi-stage negative stiffness subsystem is adjusted according to the vibration reduction requirements of the real bridge cable-stayed cable 1.

[0018] In this embodiment, the first hoop 2 is fixed to the anchorage end of the inclined cable 1 near the beam by bolts. The distance between the first hoop 2 and the anchorage point of the inclined cable 1 is 1%-3% of the length of the inclined cable 1. The first hoop 2 plays a key role in connecting the inclined cable 1 and the multi-stage negative stiffness subsystem. At the same time, the fan-shaped connecting plate at the bottom of the first hoop 2 has unique advantages. The connection area in a compact space is increased, and the three-hole design of the fan-shaped connecting plate supports the symmetrical articulation of the damper 3, which effectively realizes the synchronous control of the in-plane and out-plane vibration of the inclined cable; the vibration of the inclined cable 1 is transmitted to the two symmetrical dampers 3 and the force transmission rod 4 respectively through the first hoop 2. The force transmission rod 4 transmits the vibration to the multi-stage negative stiffness subsystem. The direction of the resultant elastic restoring force generated by the pre-compression pre-spring device 6 in the multi-stage negative stiffness subsystem is the same as that of the force transmission rod 4, forming a negative stiffness effect that amplifies the piston displacement of the damper 3. This effect helps to further increase the modal damping ratio provided by the damper 3 for the control mode of the inclined cable 1, so as to achieve effective control of the wind-rain vibration and high-order vortex vibration of the inclined cable 1; among them, the multi-stage negative stiffness subsystem adopts a design structure of layered arrangement along the axial direction of the force transmission rod 4, and the number of stages can be increased or decreased according to the vibration reduction requirements of the actual bridge inclined cable, so as to realize dynamic adjustment of the amplification factor of the damper 3.

[0019] Please refer again Figure 2 Each level of the negative stiffness subsystem includes a connecting arm 5 and two preload spring devices 6 located on either side of the dowel rod 4. The middle portion of the connecting arm 5 is fixed to the dowel rod 4, and the ends of the preload spring devices 6 are hinged to the connecting arm 5 and the Y-shaped bracket 7, respectively. The preload spring devices 6 on both sides are symmetrically arranged to eliminate eccentric loads on the dowel rod 4.

[0020] Please refer again Figure 5-Figure 7 The preload spring device 6 includes a base 601 and a sleeve 602 connected to the base 601, and a disc spring guide shaft 606 and a disc spring group 607 are arranged in the sleeve 602; the sleeve 602 is hollow inside and open at both ends, and a transverse partition 603 is arranged in the sleeve 602, and a center hole is opened on the transverse partition 603. A linear bearing 605 is arranged on one side of the transverse partition 603, and the disc spring guide shaft 606 passes through the disc spring group 607, the center hole of the transverse partition 603 and the inner ring of the linear bearing 605 in sequence.

[0021] Among them, a transverse partition 603 and a linear bearing 605 are set inside the sleeve 602 to ensure the stable movement of the disc spring guide shaft 606 and the disc spring group 607, thereby improving the durability and reliability of the system; the center hole of the transverse partition 603 constrains the radial displacement of the disc spring guide shaft 606.

[0022] In this embodiment, the base 601 and sleeve 602 are fixedly connected via a second bolt group 604. The portion of the disc spring guide shaft 606 extending outside the sleeve 602 is provided with a flange. The base 601 and the flange of the disc spring guide shaft 606 are fixedly connected via a third bolt group 608. The ends of the disc spring group 607 abut against the flanges of the diaphragm 603 and the disc spring guide shaft 606, respectively. The second and third bolt groups 604 and 608 each include at least three circumferentially spaced bolts to ensure a stable and reliable connection. After installation, the third bolt group 608 of the preload spring device 6 is removed. After removal, the preload of the disc spring group 607 is released, causing the system to enter a negative stiffness operating mode.

[0023] In the present invention, both ends of the connecting arm 5 are hinged to the base 601. The connecting arm 5 includes a first connecting arm 501, a second connecting arm 502, and a first bolt group 503. The first connecting arm 501 has an inner surface, and the second connecting arm 502 matches the first connecting arm 501 and has an inner surface. The inner surface of the second connecting arm 502 is opposite to and engages with the inner surface of the first connecting arm 501. The first bolt group 503 passes through corresponding holes in the first and second connecting arms 501, 502, and securely connects the engaged first and second connecting arms 501, 502 to the dowel rod 4. The connecting arm 5 is engaged by the first and second connecting arms 501, 502, and the first bolt group 503 radially locks the dowel rod 4. The connecting arm 5 adopts a split structure to support on-site assembly without disassembling the dowel rod 4.

[0024] Please refer again Figure 8 The Y-shaped bracket 7 includes a column and two arms forming a fork. Pairs of second clamps 701 are mounted on the two arms of the Y-shaped bracket 7. The number of pairs of second clamps 701 is the same as the number of stages of the multi-stage negative stiffness subsystem. The portion of the disc spring guide shaft 606 extending outside the sleeve 602 is hingedly connected to the second clamps 701. This structure allows the preload spring device 6 to be hingedly connected to the connecting arm 5 and the Y-shaped bracket 7 at both ends.

[0025] The working principle of the present invention is: The specific installation location of the multi-stage negative stiffness subsystem is determined according to the aesthetics and environmental coordination of the cable-damper system. The negative stiffness coefficient of the multi-stage negative stiffness subsystem and the damping coefficient of damper 3 are determined according to the vibration mode optimization of cable 1. Then, the number of stages of the multi-stage negative stiffness subsystem is determined using the negative stiffness coefficient of the first-stage negative stiffness subsystem.

[0026] When the multi-stage negative stiffness subsystem is installed at the predetermined position of the cable-stayed cable 1, the vibration energy of the cable-stayed cable 1 will be transmitted to the dampers 3 on both sides of the force transmission rod 4 for dissipation; in addition, the vibration of the cable-stayed cable 1 will drive the force transmission rod 4 and the connecting arm 5 to move synchronously, and then drive the preload spring device 6 to rotate through the connecting arm 5. The resultant elastic restoring force generated by the preload spring device 6 on both sides of the force transmission rod 4 is in the same direction as the movement of the force transmission rod 4, forming a negative stiffness effect that amplifies the piston displacement of the damper 3. This effect helps to further increase the modal damping ratio provided by the damper 3 for the control mode of the cable-stayed cable 1, so as to achieve effective control of wind-rain vibration and high-order vortex vibration of the cable 1.

[0027] In summary, the multi-stage negative stiffness-damping system suitable for vibration control of the cable-stayed cable of a real bridge provided by the present invention has the following key improvements: through the joint action of the multi-stage negative stiffness subsystem and the damper, effective control of the wind-rain vibration and high-order vortex vibration of the cable-stayed cable of the real bridge is achieved, and the three-hole design of the fan-shaped connecting plate at the bottom of the first clamp supports symmetrical articulation of the damper, effectively realizing the synchronous control of the inside and outside vibrations of the cable-stayed cable; when the cable vibrates, the force transmission rod transmits the vibration to the multi-stage negative stiffness subsystem, and the vibration of the cable is controlled by the negative stiffness effect of the pre-stressed spring device and the energy dissipation effect of the damper, and the number of stages of the multi-stage negative stiffness subsystem can be adjusted according to the vibration reduction requirements of the cable-stayed cable of the real bridge to achieve a more flexible vibration reduction control effect.

[0028] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, any equivalent changes or modifications made based on the structures, features, and principles described in the patent scope of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A multi-stage negative stiffness-damping system suitable for vibration control of stay cables in real bridges, characterized by: It comprises a first hoop (2) for fixing on the inclined cable (1), and a damper (3) and a force transmission rod (4) connected to the first hoop (2); Wherein, a fan-shaped connecting plate is provided at the bottom of the first hoop (2), and the fan-shaped connecting plate has a plurality of equally spaced connecting holes distributed along the arc direction, the damper (3) is symmetrically hinged to the connecting holes on both sides of the fan-shaped connecting plate, and the upper end of the force transmission rod (4) is hinged to the connecting hole in the center of the fan-shaped connecting plate; It also includes a Y-shaped bracket (7) and a multi-stage negative stiffness subsystem, wherein the Y-shaped bracket (7) and the damper (3) are hinged, and the multi-stage negative stiffness subsystem includes at least one stage of negative stiffness subsystem with a pre-stressed spring device (6) arranged in layers along the axial direction of the force transmission rod (4), and the number of stages of the multi-stage negative stiffness subsystem is adjusted according to the vibration reduction requirements of the actual bridge inclined cable (1).

2. The multi-stage negative stiffness-damping system suitable for vibration control of stay cables of real bridges according to claim 1 is characterized in that: Each level of the negative stiffness subsystem comprises a connecting arm (5) and two pre-stressed spring devices (6) located on both sides of the force transmission rod (4), the middle part of the connecting arm (5) is fixed on the force transmission rod (4), and the two ends of the pre-stressed spring device (6) are respectively hinged to the connecting arm (5) and the Y-shaped bracket (7).

3. The multi-stage negative stiffness-damping system suitable for vibration control of stay cables of real bridges according to claim 2 is characterized in that: The preload spring device (6) includes a base (601) and a sleeve (602) connected to the base (601), wherein a disc spring guide shaft (606) and a disc spring group (607) are arranged in the sleeve (602); the sleeve (602) is hollow inside and open at both ends, and a diaphragm (603) is arranged in the sleeve (602), wherein a center hole is opened on the diaphragm (603), and a linear bearing (605) is arranged on one side of the diaphragm (603), and the disc spring guide shaft (606) passes through the disc spring group (607), the center hole of the diaphragm (603) and the inner ring of the linear bearing (605) in sequence.

4. The multi-stage negative stiffness-damping system suitable for vibration control of stay cables of real bridges according to claim 3 is characterized in that: The base (601) and the sleeve (602) are fixedly connected by a second bolt group (604); a portion of the disc spring guide shaft (606) extending outside the sleeve (602) is provided with a flange; the base (601) and the flange of the disc spring guide shaft (606) are fixedly connected by a third bolt group (608); and the two ends of the disc spring group (607) are respectively in contact with the flanges of the diaphragm (603) and the disc spring guide shaft (606).

5. The multi-stage negative stiffness-damping system suitable for vibration control of stay cables of real bridges according to claim 3 is characterized in that: The two ends of the connecting arm (5) are hinged to the base (601), and the connecting arm (5) comprises a first connecting arm (501), a second connecting arm (502) and a first bolt group (503), wherein the first connecting arm (501) has an inner surface, and the second connecting arm (502) matches the first connecting arm (501) and has an inner surface, and the inner surface of the second connecting arm (502) is opposite to and engaged with the inner surface of the first connecting arm (501); the first bolt group (503) passes through corresponding holes on the first connecting arm (501) and the second connecting arm (502) to fix the engaged first connecting arm (501) and the second connecting arm (502) to the force transmission rod (4).

6. The multi-stage negative stiffness-damping system suitable for vibration control of stay cables of real bridges according to claim 3 is characterized in that: The Y-shaped bracket (7) comprises a column and two arms forming a fork portion. Pairs of second hoops (701) are mounted on the two arms of the Y-shaped bracket (7). The number of pairs of the second hoops (701) is the same as the number of stages of the multi-stage negative stiffness subsystem. The portion of the disc spring guide shaft (606) extending outside the sleeve (602) is hinged to the second hoops (701).

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