Adjustable three-element damper for a stay cable and method of designing the same

Abstract

The present application relates to a kind of adjustable three-damping for stay cable and its design method;The adjustable three-damping includes receiving component and damping component;Receiving component includes support, lever, connecting rod, receiving rod;Damping component includes support frame, magnetic negative stiffness unit, inertia flywheel, rotary eddy current damping unit and transmission assembly;The present application utilizes lever amplification principle, increases the displacement and speed input to damping component, amplifies the inertial parameter of damping component, equivalent negative stiffness coefficient, equivalent damping coefficient, which makes the present application more sensitive to small vibration, can effectively reduce vibration amplitude, applicable to some high-precision, high-efficiency damping application occasion.By changing the connection state of connecting rod and lever, the inertial parameter, equivalent negative stiffness coefficient, equivalent damping coefficient can be adjusted, and the damping performance of adjustable three-damping can be optimized;Its design method can adjust the inertial parameter, equivalent negative stiffness coefficient, equivalent damping coefficient according to needs.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of damper preparation, and particularly relates to an adjustable three-element damper for a stay cable and a design method thereof. BACKGROUND

[0002] The stay cable is an important component for transmitting the load of a main beam to a cable tower on a large-span bridge. The stay cable usually encounters wind-rain-induced vibration, that is, the stay cable itself produces large-amplitude vibration under the combined action of wind and rain, which seriously threatens the safety and service life of the bridge main body. The common stay cable vibration control measures include four categories of air damping, auxiliary cable, mechanical damping and hybrid measures, among which the mechanical damping measure is the most widely used. Inspired by the two-element passive damping, the tuning effect of the spring stiffness element is introduced to develop the three-element passive damping of the stay cable. Related studies show that compared with the two-element passive damping, the three-element passive damping has specific and significant advantages in the single-mode vibration control of the stay cable. The stay cable damping device of the magnetic negative stiffness damper disclosed in CN112942104A is a device using two-element passive damping; the damping device comprises a support frame, a magnetic negative stiffness unit, a rotary eddy current damping unit and a transmission mechanism; the damping device uses a ball screw to amplify the rotating speed of the rotary eddy current damping element, improves the energy dissipation efficiency of the magnetic negative stiffness damper, and effectively improves the multi-mode vibration control effect of the stay cable. However, the two-element passive damping device still has problems such as inflexible adjustment of stiffness and damping parameters, limited installation space and difficult maintenance. SUMMARY

[0003] The purpose of the present application is to solve the above problems, and provide an adjustable three-element damper for a stay cable and a design method thereof.

[0004] The technical scheme of the present application is: an adjustable three-element damper for a stay cable comprises a receiving component, a sensor and a damping component;

[0005] The receiving component comprises a support, a lever, a connecting rod and a receiving rod; a plurality of adjusting holes alpha are evenly arranged on the support; a plurality of adjusting holes beta are evenly arranged on the middle part of the lever; the upper end of the receiving rod is connected with the stay cable, and the lower end is hingedly connected with the left end of the lever; the receiving rod applies the vibration generated by the stay cable to the left end of the lever; the right end of the lever is hingedly connected with the upper end of the sensor; the lever transmits the vibration to the sensor after amplification; the sensor detects the force applied to the right end of the lever; the connecting rod is hingedly connected with the adjusting holes alpha and the adjusting holes beta at both ends; different combinations of the adjusting holes alpha and the adjusting holes beta can form different amplification multiples of the equivalent negative stiffness coefficient and the equivalent damping coefficient; the hingedly connected lower end of the connecting rod and the adjusting holes beta enable the right end of the lever to output vertical reciprocating vibration, which is conducive to the detection of the sensor and the consumption of the vibration by the damping component;

[0006] The damping component comprises a support frame, a magnetostrictive negative stiffness unit, an inertial flywheel, a rotary eddy current damping unit and a transmission assembly; the magnetostrictive negative stiffness unit, the inertial flywheel and the rotary eddy current damping unit are sequentially installed on the support frame; the magnetostrictive negative stiffness unit, the inertial flywheel and the rotary eddy current damping unit realize parallel connection of a ternary vibration reduction configuration, fully play a coordinated damping effect of the magnetostrictive negative stiffness unit, the inertial flywheel and the rotary eddy current damping unit, and the equivalent inertia of the damping component is further increased through the high rotational inertia amplification effect of the inertial flywheel; the transmission assembly vertically penetrates through the support frame and comprises a sliding rod and a rotating rod.

[0007] The magnetostrictive negative stiffness unit comprises upper permanent magnets, lower permanent magnets and a lifting plate; the upper permanent magnets and the lower permanent magnets are fixedly connected with the support frame and are circumferentially distributed around the transmission assembly; the lifting plate is provided with permanent magnet A at the top thereof; the permanent magnet A is opposite in polarity to the upper permanent magnets and is in position correspondence with the upper permanent magnets; the lifting plate is provided with permanent magnet B at the bottom thereof; the permanent magnet B is opposite in polarity to the lower permanent magnets and is in position correspondence with the lower permanent magnets.

[0008] The rotary eddy current damping unit comprises a conductor copper plate and permanent magnets C; the permanent magnets C are symmetrically arranged on the upper and lower sides of the conductor copper plate and are fixedly connected with the support frame and opposite in polarity.

[0009] The sliding rod is connected with the lower end of the sensor at the top thereof; the middle part of the sliding rod is vertically slidably connected with the top of the support frame; the bottom of the sliding rod is fixedly connected with the top of the lifting plate; the bottom of the lifting plate is provided with a ball nut which is threadedly connected with the upper end of the rotating rod; the middle part of the rotating rod is coaxially and detachably connected with the inertial flywheel and the conductor copper plate; the lower end of the rotating rod is rotatably connected with the support frame. The vertical repeated vibration transmitted by the lower end of the sensor acts on the sliding rod, so that the sliding rod drives the lifting plate to reciprocatingly lift and lower; when the lifting plate is lifted, the attraction of the upper permanent magnets to the permanent magnet A is enhanced, and the attraction of the lower permanent magnets to the permanent magnet B is weakened; when the lifting plate is lowered, the attraction of the upper permanent magnets to the permanent magnet A is weakened, and the attraction of the lower permanent magnets to the permanent magnet B is enhanced; the lifting and lowering action of the lifting plate is strengthened and amplified; the lifting plate acts on the rotating rod through the ball nut, so that the rotating rod rotates; the rotating rotating rod acts on the inertial flywheel, and most of the vibration energy is converted into mechanical energy; the lifting of the lifting plate drives the inertial flywheel to rotate in the forward direction; the lowering of the lifting plate drives the inertial flywheel to rotate in the reverse direction; thereby realizing mutual consumption of energy; the rotating rotating rod acts on the conductor copper plate; the rotating conductor copper plate is subjected to the eddy current damping under the action of the permanent magnets C, so as to consume the vibration energy transmitted by the stay cable.

[0010] Preferably, the upper permanent magnets and the lower permanent magnets are even in number and are in position correspondence, so as to ensure uniformity of the magnetostrictive negative stiffness unit in enhancing the lifting and lowering of the lifting plate.

[0011] Further, the adjacent upper permanent magnet poles are opposite; the adjacent lower permanent magnet poles are opposite; in this way, the vertical lifting stability of the lifting plate is improved, and the magnetic field intensity above and below the lifting plate is enhanced; the upper permanent magnet directly above a certain permanent magnet A shows opposite sex attraction to the permanent magnet A; the upper permanent magnets on both sides of the permanent magnet A show same sex repulsion to the permanent magnet A; the permanent magnet A is easy to maintain the vertical lifting state; similarly, the permanent magnet B and the lower permanent magnet can also produce similar matching relationship; in this way, the vertical lifting stability of the lifting plate as a whole is improved.

[0012] Further, the positions of the permanent magnet A and the permanent magnet B correspond, and the magnetism is opposite; the permanent magnet A and the permanent magnet B interact to clamp the lifting plate, and the connection relationship between the permanent magnet A, the permanent magnet B and the lifting plate is more stable.

[0013] Preferably, the middle part of the receiving rod lower end is provided with a radial slot; the left end of the lever is provided with a radial strip extending outward and matched with the radial slot; the radial slot is provided with a hinge hole A; the radial strip is provided with a hinge hole B hinged with the hinge hole A; the distance L1 from the hinge hole A to the inner end of the radial slot is less than the distance L2 from the hinge hole B to the outer edge of the radial strip; the radial strip and the radial slot cooperate to limit the rotation range of the lever within a certain range, preventing the sliding shaft from moving back and forth on the axis beyond the safety limit.

[0014] Preferably, the middle part of the sliding rod is vertically slidably connected with the top of the support frame through a linear bearing, avoiding the vertical vibration directly acting on the inner wall of the support frame, increasing the contact friction between the sliding shaft and the support frame, and damaging the surface of the sliding rod and the support frame.

[0015] Preferably, the sliding rod and the rotating rod are coaxially arranged, which is conducive to the transmission of vertical vibration.

[0016] Further, the lower end of the sliding rod is provided with a cavity corresponding to the upper end of the rotating rod; the upper end of the rotating rod is inserted into the cavity; in this way, the top end of the rotating rod is prevented from colliding with the top end of the sliding shaft cavity when the sliding shaft moves downward, causing damage to both, and the structure of the damping component is more compact.

[0017] Preferably, the middle part of the rotating rod is provided with a square column segment; the inertia flywheel is in the shape of a disc, including a half disc A, a half disc B, a connecting piece, a connecting bolt and a connecting nut; the half disc A and the half disc B are respectively provided with a notch A and a notch B corresponding to the square column segment at the center; the notch A and the notch B cooperate with each other to form a limiting connection with the square column segment, preventing the inertia flywheel and the outer wall of the rotating rod from rotating and slipping during the common rotation; the connecting piece has at least two, arranged on both sides of the square column segment; the bottom of the connecting piece is connected with the half disc A and the half disc B; the end of the connecting bolt is threadedly connected with the connecting nut; the middle part of the connecting bolt penetrates the half disc A / half disc B and the connecting piece; the inertia flywheel and the rotating rod form a detachable structure, which is convenient for replacing the inertia flywheel according to needs.

[0018] Further, the square column section of the rotating rod is externally provided with a convex edge at the upper end and the lower end; the convex edge axially limits the inertia flywheel, and increases the connection stability of the inertia flywheel and the rotating rod.

[0019] Preferably, a flange nut is arranged below the conductor copper plate; the flange nut comprises a flange plate and a nut body coaxially connected; the flange plate is connected with the conductor copper plate through bolts and nuts; the nut body is threadedly connected with the lower end of the rotating rod; and the flange nut realizes detachable connection of the conductor copper plate.

[0020] Preferably, the support frame is mounted on the support, so that the overall structure is more stable.

[0021] A design method of the adjustable three-element damper for the stay cable comprises the following steps:

[0022] ①Investigate the wind-induced vibration condition of the stay cable, and determine the vibration frequency of the stay cable;

[0023] ②Determine the stiffness parameter requirement and the damping parameter requirement of the adjustable three-element damper for the stay cable installed on the main beam according to the vibration frequency of the stay cable;

[0024] ③Adjust the inerter coefficient of the inertia flywheel, the number of permanent magnet groups of the magnetic negative stiffness unit and the rotary eddy current damping unit, and the hinge positions at the two ends of the connecting rod according to the stiffness parameter requirement of the adjustable three-element damper;

[0025] ④Design and develop a prototype of the adjustable three-element damper and perform mechanical performance test; the test result is stable in performance and the design is reasonable;

[0026] ⑤Carry out forced vibration test of each order of the model cable and vibration reduction test of the adjustable three-element damper-cable.

[0027] The adjustable three-element damper for the stay cable has the following advantages:

[0028] (1) The damper part of the present application is amplified by the lever amplification principle, which increases the displacement and velocity input to the damper part, thereby amplifying the mass parameter, equivalent negative stiffness coefficient and equivalent damping coefficient of the damper part, which makes the present application more sensitive to small vibrations, effectively reduces the vibration amplitude, and is suitable for some high-precision and high-efficiency vibration reduction applications. By changing the connection state of the connecting rod and the lever, the mass parameter, equivalent negative stiffness coefficient and equivalent damping coefficient can be adjusted, and the vibration reduction performance of the adjustable three-element damper can be optimized;

[0029] (2) The magnetic negative stiffness unit, the inertia flywheel and the rotary eddy current damping unit are connected in parallel, the coordinated damping effect of the magnetic negative stiffness unit, the inertia flywheel and the rotary eddy current damping unit is fully exerted, the amplification effect is realized through the high rotational inertia of the inertia flywheel, and the equivalent inertia of the damping component is increased;

[0030] (3) The inertia flywheel and the rotating rod form a detachable structure, so that the inertia flywheel can be replaced according to needs.

[0031] (4) The adjustable three-element damper for a stay cable has high adaptability, simple structure, convenient installation and strong energy dissipation, and solves the difficulties of traditional dampers in space limitation, size, load distribution, installation and maintenance and the like.

[0032] The design method can adjust the inertial mass parameter, the equivalent negative stiffness coefficient and the equivalent damping coefficient according to needs. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a perspective view of the adjustable three-element damper for a stay cable;

[0034] Figure 2 is an I enlarged view of Figure 1

[0035] Figure 3 is a side view of Figure 1

[0036] Figure 4 is an A-A sectional view of Figure 3

[0037] Figure 5 is an II enlarged view of Figure 4

[0038] Figure 6 is a B-B sectional view of Figure 4

[0039] Figure 7 is a C-C sectional view of Figure 5

[0040] Figure 8 is a D-D sectional view of Figure 5

[0041] Figure 9 is an E-E sectional view of Figure 5

[0042] Figure 10 is a comparison between the test value and the theoretical value of the axial force time history curve of the adjustable three-element damper;

[0043] Figure 11 ​​​​​​​​is a comparison chart of simulation value and test value of equivalent inertia mass in mechanical property test of adjustable ternary damper;

[0044] Figure 12 is a comparison chart of simulation value and test value of equivalent negative stiffness coefficient in mechanical property test of adjustable ternary damper;

[0045] Figure 13 is a free decay curve of acceleration of a measuring point at the mid-span position of the first order mode of the stay cable;

[0046] Figure 14 is a photograph of the adjustable ternary damper;

[0047] Figure 15 is a photograph of the damping test of the adjustable ternary damper;

[0048] In the figure: 11. support, 111. adjusting hole A, 12. lever, 121. adjusting hole B, 122. radial strip, 13. connecting rod, 14. receiving rod, 141. radial groove, 2. sensor, 311. linear bearing, 312. upper frame, 3121. upper top plate, 3122. upper bottom plate, 3123. upper support column, 31231. threaded hole, 313. middle frame, 3131. middle support column, 31311. upper threaded section, 31312. lower threaded section, 314. lower frame, 3141. lower top plate, 3142. lower bottom plate, 31421. thrust bearing, 3143. lower support column, 315. nut, 32. magnetically-induced negative stiffness unit, 321. upper permanent magnet, 322. lower permanent magnet, 323. lifting plate, 3231. permanent magnet A, 3232. permanent magnet B, 3233. ball nut, 33. inertia flywheel, 331. half disc A, 3311. notch A, 332. half disc B, 3321. notch B, 333. connecting sheet, 334. connecting bolt, 335. connecting nut, 34. rotary electric eddy current damping unit, 341. conductor copper plate, 342. permanent magnet C, 3431. flange plate, 3432. nut body, 351. sliding rod, 3511. cavity, 352. rotating rod, 3521. square column section, 3522. convex edge. DETAILED DESCRIPTION

[0049] Example One: Refer to Figures 1-9 An adjustable ternary damper for a stay cable includes a receiving component, a sensor 2, and a damping component;

[0050] The receiving component comprises a support 11, a lever 12, a connecting rod 13 and a receiving rod 14. The support 11 is horizontally provided with a plurality of adjusting holes 111. The lever 12 is horizontally provided with a plurality of adjusting holes 121. In the embodiment, each of the adjusting holes 111 and the adjusting holes 121 has four holes. The upper end of the receiving rod 14 is connected with the stay cable, and the lower end is hingedly connected with the left end of the lever 12. The receiving rod 14 transmits the vibration generated by the stay cable to the left end of the lever 12. The right end of the lever 12 is hingedly connected with the upper end of the sensor 2. The lever 12 transmits the vibration to the sensor 2 after amplification. The sensor 2 detects the force applied to the right end of the lever 12. The two ends of the connecting rod 13 are hingedly connected with the adjusting holes 111 and the adjusting holes 121, respectively. Different combinations of the adjusting holes 111 and the adjusting holes 121 can form different amplification multiples of the equivalent negative stiffness coefficient and the equivalent damping coefficient. The hingedly connected lower end of the connecting rod 13 with the adjusting holes 121 enables the right end of the lever 12 to output vertical reciprocating vibration, which is conducive to the detection of the sensor 2 and the consumption of the vibration by the damping component.

[0051] The distance between the left end of the adjusting hole 111 of the lever 12 and the hingedly connected lower end of the receiving rod 14 is called the load arm. The distance between the adjusting hole 111 of the lever 12 and the hingedly connected upper end of the sensor 2 is called the force arm. The position of the translating connecting rod 13 is changed to change the different amplification multiples. According to the principle of similar triangles, the ratio of the vertical displacement of the force arm end to the vertical displacement of the load arm end is equal to the ratio of the length of the force arm to the length of the load arm, i.e. x1 / x2=l1 / l2, wherein l1, l2, x1 and x2 are the length of the force arm, the length of the load arm, the vertical displacement of the force arm end and the vertical displacement of the load arm end, respectively.

[0052] According to the principle of energy conservation, in the lever 12 system, the force and length relationship at the ends of the force arm and the load arm follows the formula: input force x force arm length = output force x load arm length, i.e. f1x l1=f2x l2, wherein f1 and f2 are the input force and the output force, respectively. Combined with the formula k i =f i / x i , k i is the equivalent negative stiffness coefficient, the equivalent negative stiffness coefficient amplification multiple at different positions of the connecting rod 13 can be obtained. Similarly, according to c i =f i / v i , the equivalent damping coefficient amplification multiple at different positions of the connecting rod 13 can be obtained, v i is the axial velocity.

[0053] The adjustment hole 111 with the same length of the load arm and the force arm is the center position of the lever 12, at this time, the displacement amplification factor is 1, and the equivalent negative stiffness coefficient and the equivalent damping coefficient amplification factor are also 1; the other three adjustment holes 111 are equidistant, and through the above theory, the equivalent negative stiffness coefficient and the equivalent damping coefficient amplification factor are the square of the ratio of the length of the force arm and the length of the load arm, respectively.

[0054] The damping component comprises a support frame, a magnetic negative stiffness unit 32, an inertia flywheel 33, a rotary eddy current damping unit 34 and a transmission assembly; the magnetic negative stiffness unit 32, the inertia flywheel 33 and the rotary eddy current damping unit 34 are sequentially installed on the support frame; the magnetic negative stiffness unit 32, the inertia flywheel 33 and the rotary eddy current damping unit 34 realize parallel connection of the ternary damping configuration, fully play the coordinated damping effect of the magnetic negative stiffness unit 32, the inertia flywheel 33 and the rotary eddy current damping unit 34, and increase the equivalent inertia of the damping component through the high rotational inertia amplification effect of the inertia flywheel 33; the transmission assembly vertically penetrates the support frame and comprises a sliding rod 351 and a rotating rod 352;

[0055] The magnetic negative stiffness unit 32 comprises an upper permanent magnet 321, a lower permanent magnet 322 and a lifting plate 323; the upper permanent magnet 321 and the lower permanent magnet 322 are fixedly connected with the support frame and are circumferentially distributed around the transmission assembly; the lifting plate 323 is provided with a permanent magnet A 3231 on the top; the permanent magnet A 3231 corresponds to the upper permanent magnet 321 in position and is opposite in polarity; the lifting plate 323 is provided with a permanent magnet B 3232 on the bottom; the permanent magnet B 3232 corresponds to the lower permanent magnet 322 in position and is opposite in polarity;

[0056] The rotary eddy current damping unit 34 comprises a conductor copper plate 341 and a permanent magnet C 342; the permanent magnet C 342 is symmetrically arranged on the upper and lower sides of the conductor copper plate 341 and is fixedly connected with the support frame;

[0057] The top of the sliding rod 351 is connected with the lower end of the sensor 2, the middle of the sliding rod 351 is vertically slidably connected with the top of the support frame, and the bottom of the sliding rod 351 is fixedly connected with the top of the lifting plate 323. The bottom of the lifting plate 323 is provided with a ball nut 3233 which is threadedly connected with the upper end of a rotating rod 352. The middle of the rotating rod 352 is coaxially and detachably connected with an inertia flywheel 33 and a conductor copper plate 341. The lower end of the rotating rod 352 is rotatably connected with the support frame. The vertical and repeated vibration transmitted by the lower end of the sensor 2 acts on the sliding rod 351, so that the sliding rod 351 drives the lifting plate 323 to reciprocatingly lift. When the lifting plate 323 lifts, the suction force of the upper permanent magnet 321 to the permanent magnet A 3231 is enhanced, and the suction force of the lower permanent magnet 322 to the permanent magnet B 3232 is weakened. When the lifting plate 323 descends, the suction force of the upper permanent magnet 321 to the permanent magnet A 3231 is weakened, and the suction force of the lower permanent magnet 322 to the permanent magnet B 3232 is enhanced. The lifting action of the lifting plate 323 is strengthened and amplified. The lifting plate 323 acts on the rotating rod 352 through the ball nut 3233, so that the rotating rod 352 rotates. The rotating rotating rod 352 acts on the inertia flywheel 33, and most of the vibration energy is converted into mechanical kinetic energy. The lifting of the lifting plate 323 drives the forward rotation of the inertia flywheel 33. The descent of the lifting plate 323 drives the reverse rotation of the inertia flywheel 33. Thus, the energy is consumed. The rotating rotating rod 352 acts on the conductor copper plate 341. The rotating conductor copper plate 341 is subjected to the action of the permanent magnet C 342, and the eddy current damping is realized. The vibration energy transmitted by the cable-stayed cable is consumed.

[0058] Compared with the prior art, the present application amplifies the displacement and speed input to the damping component by the amplification principle of the lever 12, thereby amplifying the mass parameter, equivalent negative stiffness coefficient and equivalent damping coefficient of the damping component. This makes the present application more sensitive to slight vibration, effectively reduces the vibration amplitude, and is suitable for some high-precision and high-efficiency vibration reduction applications. By changing the connection state of the connecting rod 13 and the lever 12, the mass parameter, equivalent negative stiffness coefficient and equivalent damping coefficient can be adjusted to optimize the vibration reduction performance of the adjustable three-element damper.

[0059] The magnetic negative stiffness unit 32, the inertia flywheel 33 and the rotary eddy current damping unit 34 are connected in parallel in the present application, and the coordinated vibration reduction effect of the magnetic negative stiffness unit 32, the inertia flywheel 33 and the rotary eddy current damping unit 34 is fully utilized. The amplification effect is realized by using the high rotational inertia of the inertia flywheel 33, and the equivalent inertia of the damping component is increased.

[0060] The number of the upper permanent magnets 321 and the lower permanent magnets 322 is even and the positions are corresponding, which ensures the uniformity of the lifting efficiency of the magnetic negative stiffness unit 32 to the lifting plate 323.

[0061] The adjacent upper permanent magnets 321 have opposite magnetic poles; the adjacent lower permanent magnets 322 have opposite magnetic poles; in this way, the vertical lifting stability of the lifting plate 323 is improved, and the magnetic field intensity above and below the lifting plate 323 is enhanced; the upper permanent magnet 321 directly above a certain permanent magnet A 3231 shows opposite sex attraction to the permanent magnet A 3231; the upper permanent magnets 321 on both sides above the permanent magnet A 3231 show same sex repulsion to the permanent magnet A 3231; the permanent magnet A 3231 is easy to maintain the vertical lifting state; similarly, the permanent magnet B 3232 and the lower permanent magnet 322 can also produce similar matching relationship; in this way, the vertical lifting stability of the lifting plate 323 as a whole is improved.

[0062] The positions of the permanent magnet A 3231 and the permanent magnet B 3232 correspond to each other and are opposite in magnetic properties; the permanent magnet A 3231 and the permanent magnet B 3232 interact to clamp the lifting plate 323, and the connection relationship between the permanent magnet A 3231, the permanent magnet B 3232 and the lifting plate 323 is more stable.

[0063] The lower end of the receiving rod 14 is provided with a radial groove 141; the left end of the lever 12 is provided with a radial strip 122 extending outward and matched with the radial groove 141; the radial groove 141 is provided with a hinge hole A; the radial strip 122 is provided with a hinge hole B hinged with the hinge hole A; the distance L1 from the hinge hole A to the inner end of the radial groove 141 is less than the distance L2 from the hinge hole B to the outer edge of the radial strip 122; the radial strip 122 cooperates with the radial groove 141 to limit the rotation range of the lever 12 within a certain range, preventing the sliding shaft of the damping part from moving back and forth in the axial direction beyond the safety limit.

[0064] The middle part of the sliding rod 351 is vertically slidably connected with the top of the support frame through a linear bearing 311, so as to avoid the vertical vibration acting on the support frame, increase the contact friction force between the sliding shaft and the support frame, and damage the surface of the sliding rod 351 and the support frame.

[0065] The sliding rod 351 is coaxially arranged with the rotating rod 352, which is conducive to the transmission of vertical vibration.

[0066] The lower end of the sliding rod 351 is provided with a larger cavity 3511 than the upper end of the rotating rod 352; the upper end of the rotating rod 352 is inserted into the cavity 3511; in this way, the top end of the rotating rod 352 is prevented from colliding with the top end of the cavity 3511 of the sliding shaft when the sliding shaft moves downward, causing damage to both, and the structure of the damping part is more compact.

[0067] The middle part of the rotating rod 352 is provided with a square column section 3521; the inertia flywheel 33 is in the shape of a disc, comprising a semi-disc A 331, a semi-disc B 332, a connecting plate 333, a connecting bolt 334, and a connecting nut 335; the semi-disc A 331 and the semi-disc B 332 are respectively provided with a notch A 3311 and a notch B 3321 corresponding to the square column section 3521; the notch A 3311 and the notch B 3321 are matched with each other to form a limiting connection with the square column section 3521, preventing the inertia flywheel 33 from rotating and slipping when rotating together with the outer wall of the rotating rod 352; the connecting plate 333 is provided with at least two connecting plates 333 distributed on both sides of the square column section 3521; the bottom of the connecting plate 333 is connected with the semi-disc A 331 and the semi-disc B 332; the end of the connecting bolt 334 is threadedly connected with the connecting nut 335; the middle part of the connecting bolt 334 penetrates through the semi-disc A 331 / semi-disc B 332 and the connecting plate 333; the inertia flywheel 33 and the rotating rod 352 form a detachable structure, which is convenient for replacing the inertia flywheel 33 according to needs. The connecting plate 333 in the embodiment has two connecting plates 333.

[0068] The square column section 3521 of the rotating rod 352 is provided with a protrusion 3522 at the upper and lower ends; the protrusion 3522 axially limits the inertia flywheel 33, increasing the connection stability of the inertia flywheel 33 and the rotating rod 352.

[0069] The conductor copper plate 341 is provided below with a flange nut; the flange nut comprises a flange plate 3431 and a nut body 3432 coaxially connected; the flange plate 3431 is connected with the conductor copper plate 341 through the bolt and the nut 315; the nut body 3432 is threadedly connected with the lower end of the rotating rod 352; the flange nut realizes detachable connection of the conductor copper plate 341.

[0070] The support frame comprises an upper frame 312, a middle frame 313, and a lower frame 314; the upper frame 312 comprises an upper top plate 3121, an upper bottom plate 3122, and an upper support column 3123; the upper permanent magnet 321 is connected with the bottom of the upper top plate 3121; the lower permanent magnet 322 is connected with the top of the upper bottom plate 3122; the upper support column 3123 is circumferentially distributed around the transmission assembly, connecting the upper top plate 3121 and the upper bottom plate 3122; the lower frame 314 comprises a lower top plate 3141, a lower bottom plate 3142, and a lower support column 3143; the lower end of the rotating rod 352 is rotationally connected with the lower bottom plate 3142; the lower support column 3143 is circumferentially distributed around the transmission assembly, connecting the lower top plate 3141 and the lower bottom plate 3142; the middle frame 313 comprises a middle support column 3131; the middle support column 3131 is circumferentially distributed around the transmission assembly, connecting the upper bottom plate 3122 and the lower top plate 3141.

[0071] The upper support column 3123 upper end penetrates the upper top plate 3121, and is screwed with a nut 315; the upper support column 3123 lower end is coaxially provided with a threaded hole 31231; the middle support column 3131 upper end is provided with an upper threaded section 31311 screwed with the threaded hole 31231; the middle support column 3131 lower end is provided with a lower threaded section 31312; the lower threaded section 31312 penetrates the lower top plate 3141, and is screwed with a nut 315.

[0072] The lower top plate 3141 is installed with a thrust bearing 31421; the thrust bearing 31421 is connected with the rotating rod 352.

[0073] Embodiment two: Embodiment two is basically the same as embodiment one, and the same parts will not be repeated. The difference is that the support frame is installed on the support 11, so that the overall structure is more stable; the support frame and the support 11 are integrated, and can be directly installed on the main body of the building.

[0074] Embodiment three: see Figures 10-13 A design method of the adjustable three-element damper for the stay cable described in embodiment one, comprising the following steps:

[0075] ①Investigate the wind-induced vibration of the stay cable, and determine the vibration frequency of the stay cable;

[0076] ②According to the vibration frequency of the stay cable, determine the stiffness parameter requirement and the damping parameter requirement of the adjustable three-element damper installed on the main beam of the stay cable;

[0077] ③According to the stiffness parameter requirement of the adjustable three-element damper, adjust the inertial flywheel 33, the inertial coefficient, the magnetic negative stiffness unit 32, the permanent magnet group number of the rotating eddy current damping unit 34, and the hinge position at both ends of the connecting rod 13.

[0078] ④Design and develop the adjustable three-element damper prototype and perform mechanical performance test. The test results are stable in performance and reasonable in design.

[0079] See Figure 10 It can be concluded that the relative error between the simulation value and the test value of the mechanical performance test of the three-element damper is within 15%, and the results show that the design method of the developed three-element damper is correct, the parameters are stable, and the performance is good.

[0080] ⑤Carry out the model stay cable 1, 2, and 3 order forced vibration test and the adjustable three-element damper-stay cable vibration reduction test.

[0081] After the exciter is turned off, the stay cable enters a free decay vibration state. Figure 13 The acceleration free decay curve of the stay cable at the first order modal midspan position is given by Figure 13It is found that the vibration acceleration of the cable under each working condition presents a typical logarithmic decay law. The first-order modal damping ratio of the cable increases from 0.09% (without control) to 1.71% (adjustable one-unit damper control), to 2.25% (adjustable two-unit damper control), and to 3.10% (adjustable three-unit damper control). The analysis of the test results of the adjustable three-unit damper-cable vibration reduction verifies the vibration reduction effect of the adjustable three-unit damper-cable and the feasibility of the design method of the adjustable three-unit damper for cable vibration reduction.

Claims

1. An adjustable three-dimensional damper for stay cables, characterized in that, Includes receiving components, sensors, and damping components; The receiving component includes a support, a lever, a connecting rod, and a receiving rod; the support has several adjustment holes A evenly distributed horizontally; the lever has several adjustment holes B evenly distributed horizontally in the middle; the upper end of the receiving rod is connected to the inclined cable, and the lower end is hinged to the left end of the lever; the right end of the lever is hinged to the upper end of the sensor; the two ends of the connecting rod are respectively hinged to adjustment holes A and adjustment holes B. The damping components include a support frame, a magnetostrictive negative stiffness unit, an inertial flywheel, a rotating eddy current damping unit, and a transmission assembly; the magnetostrictive negative stiffness unit, the inertial flywheel, and the rotating eddy current damping unit are sequentially mounted on the support frame; the transmission assembly extends vertically through the support frame and includes a sliding rod and a rotating rod; The magnetostrictive negative stiffness unit includes an upper permanent magnet, a lower permanent magnet, and a lifting plate; both the upper and lower permanent magnets are fixed to the support frame and are distributed around the circumference of the transmission component; a permanent magnet A is provided at the top of the lifting plate; the position of permanent magnet A corresponds to that of the upper permanent magnet, but the polarity is opposite; a permanent magnet B is provided at the bottom of the lifting plate; the position of permanent magnet B corresponds to that of the lower permanent magnet, but the polarity is opposite. The rotating eddy current damping unit includes a conductor copper plate and a permanent magnet C; the permanent magnet C is symmetrically arranged on the upper and lower sides of the conductor copper plate, fixed to the support frame, and has opposite polarities. The top of the sliding rod is connected to the lower end of the sensor; the middle of the sliding rod is vertically slidably connected to the top of the support frame; the bottom of the sliding rod is fixedly connected to the top of the lifting plate; a ball nut that is threaded to the upper end of the rotating rod is installed at the bottom of the lifting plate; an inertial flywheel and a conductor copper plate are detachably connected coaxially in the middle of the rotating rod; the lower end of the rotating rod is rotatably connected to the support frame. The rotating rod has a square column section in the middle; the inertia flywheel is disc-shaped, including semi-disc A, semi-disc B, connecting plate, connecting bolt, and connecting nut; semi-disc A and semi-disc B have notches A and B at their centers that match the square column section respectively; there are at least two connecting plates, which are set on both sides of the square column section; the bottom of the connecting plate is connected to semi-disc A and semi-disc B; the end of the connecting bolt is threaded to the connecting nut; the middle of the connecting bolt passes through semi-disc A / semi-disc B and the connecting plate.

2. The adjustable three-dimensional damper for stay cables according to claim 1, characterized in that: A radial groove is provided at the middle of the lower end of the receiving rod; a radial strip extending outward and matching the radial groove is provided at the left end of the lever; a hinge hole A is provided in the radial groove; a hinge hole B is provided in the radial strip and hinges to the hinge hole A; the distance L1 from the hinge hole A to the inner end of the radial groove is less than the distance L2 from the hinge hole B to the outer edge of the radial strip.

3. An adjustable three-dimensional damper for stay cables according to claim 1, characterized in that: The middle part of the sliding rod is vertically slidably engaged with the top of the support frame via a linear bearing.

4. An adjustable three-dimensional damper for stay cables according to claim 1, characterized in that: The sliding rod and the rotating rod are set coaxially.

5. An adjustable three-dimensional damper for stay cables according to claim 4, characterized in that: The lower end of the sliding rod has a cavity that corresponds to and matches the upper end of the rotating rod; the upper end of the rotating rod is inserted into the cavity.

6. An adjustable three-dimensional damper for stay cables according to claim 1, characterized in that: The square column section of the rotating rod has protruding edges at both the top and bottom.

7. An adjustable three-dimensional damper for stay cables according to claim 1, characterized in that: A flange nut is provided below the conductor copper plate; the flange nut includes a flange and a nut body that are coaxially connected; the flange is connected to the conductor copper plate by bolts and nuts; the nut body is threaded to the lower end of the rotating rod.

8. An adjustable three-dimensional damper for stay cables according to claim 1, characterized in that: The support frame is mounted on the support.

9. A design method for an adjustable three-dimensional damper for stay cables as described in claim 1, characterized in that: Includes the following steps: ① Investigate the wind and rain excitation conditions of the cable-stayed cable and determine its vibration frequency; ② Determine the stiffness and damping parameter requirements of the adjustable three-dimensional damper for the stay cable installed on the main beam based on the vibration frequency of the stay cable; ③ Adjust the inertia coefficient of the inertial flywheel, the number of permanent magnet groups of the magnetostrictive negative stiffness unit and the rotating eddy current damping unit, and the hinge position at both ends of the connecting rod according to the stiffness parameter requirements of the adjustable three-dimensional damper. ④ Design and develop an adjustable three-dimensional damper prototype and conduct mechanical performance tests; ⑤ Conduct forced vibration tests of various orders of model cables and vibration reduction tests of adjustable three-dimensional dampers-cables.

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