Adjustable ternary damper for stay cable and design method of adjustable ternary damper

Abstract

The invention relates to an adjustable ternary damper for a stay cable and a design method of the adjustable ternary damper. The adjustable ternary damper comprises a receiving part and a damping part. The receiving part comprises a support, a lever, a connecting rod and a receiving rod; the damping component comprises a supporting frame, a magnetic negative stiffness unit, an inertia flywheel, a rotary eddy current damping unit and a transmission assembly. By means of the lever amplification principle, the displacement and speed input to the damping component are increased, and the inertia parameter, the equivalent negative stiffness coefficient and the equivalent damping coefficient of the damping component are amplified, so that the device is more sensitive to tiny vibration, can effectively reduce the vibration amplitude and is suitable for application occasions with high precision and efficient vibration reduction. By changing the connecting state of the connecting rod and the lever, the inertia parameter, the equivalent negative stiffness coefficient and the equivalent damping coefficient can be adjusted, and the vibration reduction performance of the adjustable ternary damper is optimized; according to the design method, the inertial parameters, the equivalent negative stiffness coefficient and the equivalent damping coefficient can be adjusted according to needs.

Description

Technical Field

[0001] The invention relates to the technical field of damper preparation, and in particular to an adjustable three-dimensional damper for a stay cable and a design method thereof. Background Art

[0002] The cable-stayed cable is an important component for transmitting the main beam load to the cable tower on a long-span bridge. Under normal circumstances, the cable-stayed cable will encounter the phenomenon of wind-rain excitation, that is, under the combined action of wind and rain, the cable-stayed cable itself will produce large-scale vibrations, posing a serious threat to the safety and service life of the bridge body. At present, the common vibration control measures for the cable-stayed cable include four categories: pneumatic, auxiliary cable, mechanical damping and mixed measures, among which mechanical damping measures are the most widely used. Inspired by the binary passive vibration reduction, the tuning effect of the spring stiffness element was introduced to develop into the three-dimensional passive vibration reduction of the cable-stayed cable. Related studies have shown that compared with the binary passive vibration reduction, the three-dimensional passive vibration reduction has specific and significant advantages in the single-mode vibration control of the cable-stayed cable. A magnetic negative stiffness damper cable-stayed vibration reduction device published in publication number CN112942104A is a device that utilizes binary passive vibration reduction; the vibration reduction device includes a support frame, a magnetic negative stiffness unit, a rotary eddy current damping unit, and a transmission mechanism; the vibration reduction device utilizes a ball screw to amplify the rotation speed of the rotary eddy current damping element, improves the energy efficiency of the magnetic negative stiffness damper, and effectively improves the multi-modal vibration control effect of the cable-stayed cable. However, this type of binary passive vibration reduction device still has problems such as stiffness, inflexible damping parameter adjustment, limited installation space, and difficult maintenance. Summary of the invention

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

[0004] The technical solution of the present invention is: an adjustable three-element damper for a stay cable comprises a receiving component, a sensor and a damping component; The receiving component includes a support, a lever, a connecting rod, and a receiving rod; a plurality of adjusting holes A are evenly distributed horizontally on the support; a plurality of adjusting holes B are evenly distributed horizontally in the middle of the lever; 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 receiving rod applies the vibration generated by the inclined cable to the left end of the lever; the right end of the lever is hinged to the upper end of the sensor; the lever amplifies the vibration and transmits it to the sensor; the sensor detects the force applied to the right end of the lever; the two ends of the connecting rod are hinged to the adjusting hole A and the adjusting hole B respectively; different combinations of adjusting holes A and adjusting holes B can form equivalent negative stiffness coefficients and equivalent damping coefficients with different magnification factors; the hinge of the lower end of the connecting rod and the adjusting hole B enables the right end of the lever to output vertical reciprocating vibration, which is beneficial to sensor detection and vibration consumption by the damping component; The damping component includes a support frame, a magnetic negative stiffness unit, an inertial flywheel, a rotating eddy current damping unit and a transmission assembly; the magnetic negative stiffness unit, the inertial flywheel and the rotating eddy current damping unit are sequentially installed on the support frame; the magnetic negative stiffness unit, the inertial flywheel and the rotating eddy current damping unit realize the parallel connection of a three-dimensional vibration reduction configuration, give full play to the coordinated vibration reduction effect of the magnetic negative stiffness unit, the inertial flywheel and the rotating eddy current damping unit, and increase the equivalent inertia of the damping component by adopting the high rotational inertia amplification effect of the inertial flywheel; the transmission assembly vertically penetrates the support frame, and includes a sliding rod and a rotating rod; The magnetic negative stiffness unit includes an upper permanent magnet, a lower permanent magnet, and a lifting plate; the upper permanent magnet and the lower permanent magnet are both fixedly connected to the support frame and are distributed around the circumference of the transmission component; a permanent magnet A is arranged on the top of the lifting plate; the permanent magnet A corresponds to the position of the upper permanent magnet and has an opposite polarity; a permanent magnet B is arranged on the bottom of the lifting plate; the permanent magnet B corresponds to the position of the lower permanent magnet and has an opposite polarity; The rotary eddy current damping unit comprises 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, fixedly connected 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 matched with the top of the supporting frame; the bottom of the sliding rod is fixedly connected to the top of the lifting plate; a ball nut that matches the thread of the upper end of the rotating rod is installed at the bottom of the lifting plate; the middle of the rotating rod is coaxially and detachably connected with the inertia flywheel and the conductor copper plate; the lower end of the rotating rod is rotatably connected to the supporting frame. The vertical repetitive vibration transmitted from the lower end of the sensor acts on the sliding rod, so that the sliding rod drives the lifting plate to lift and lower back and forth; when the lifting plate rises, the upper permanent magnet's suction force on permanent magnet A is enhanced, and the lower permanent magnet's suction force on permanent magnet B is weakened; when the lifting plate descends, the upper permanent magnet's suction force on permanent magnet A is weakened, and the lower permanent magnet's suction force on permanent magnet B is enhanced; the lifting action of the lifting plate is strengthened and amplified; the lifting plate acts on the rotating rod through the ball nut to rotate the rotating rod; the rotating rotating rod acts on most of the vibration energy on the inertial flywheel and converts it into mechanical kinetic energy; the lifting plate rises to drive the inertial flywheel to rotate forward; the lifting plate descends to drive the inertial flywheel to rotate reversely, thereby realizing mutual consumption of energy; the rotating rotating rod acts on the conductor copper plate; under the action of permanent magnet C, the rotating conductor copper plate realizes eddy current damping to consume the vibration energy transmitted by the inclined cable.

[0005] Preferably, the upper permanent magnets and the lower permanent magnets are an even number with equal numbers and corresponding positions, so as to ensure the uniformity of the lifting and lowering efficiency enhancement of the lifting plate by the magnetically induced negative stiffness unit.

[0006] Furthermore, the magnetic poles of adjacent upper permanent magnets are opposite; the magnetic poles of adjacent lower permanent magnets are opposite; in this way, the vertical lifting stability of the lifting plate is improved, and at the same time, the magnetic field strength above and below the lifting plate is enhanced; the upper permanent magnet directly above a permanent magnet A shows opposite attraction to the permanent magnet A; the upper permanent magnets on both sides above the permanent magnet A show like repulsion to the permanent magnet A; the permanent magnet A can easily maintain the vertical lifting state; similarly, permanent magnet B and the lower permanent magnet can also produce a similar matching relationship; in this way, the overall vertical lifting stability of the lifting plate is improved.

[0007] Furthermore, the positions of permanent magnet A and permanent magnet B correspond and their magnetic properties are opposite; permanent magnet A and permanent magnet B interact with each other to clamp the lifting plate, and the connection relationship between permanent magnet A, permanent magnet B and the lifting plate is more stable.

[0008] Preferably, a radial groove is provided in 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 on the radial strip hinged 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; the radial strip cooperates with the radial groove to limit the rotation range of the lever within a certain range, thereby preventing the axial back-and-forth movement of the sliding shaft of the damping component beyond the safety limit.

[0009] Preferably, the middle part of the sliding rod is vertically slidably matched with the top of the support frame through a linear bearing to prevent vertical vibration from 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 sliding rod surface and the support frame.

[0010] Preferably, the sliding rod and the rotating rod are coaxially arranged, which is beneficial to the transmission of vertical vibration.

[0011] Furthermore, a cavity corresponding to the upper end of the rotating rod is provided at the lower end of the sliding rod; the upper end of the rotating rod is inserted into the cavity; in this way, when the sliding shaft moves downward, the top end of the rotating rod is prevented from colliding with the top end of the sliding shaft cavity, causing damage to both, and at the same time, the damping component structure is made more compact.

[0012] Preferably, a square column section is provided in the middle of the rotating rod; the inertia flywheel is disc-shaped as a whole, including semi-disc A, semi-disc B, a connecting plate, a connecting bolt, and a connecting nut; semi-disc A and semi-disc B are respectively provided with notches A and B in the center that match the square column section; notches A and B cooperate with each other to form a limiting connection with the square column section to prevent the inertia flywheel and the outer wall of the rotating rod from rotating and slipping when they rotate together; there are at least two connecting plates, which are arranged 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 threadedly connected to the connecting nut; the middle of the connecting bolt passes through semi-disc A / semi-disc B and the connecting plate; the inertia flywheel and the rotating rod form a detachable structure, which is convenient for replacing the inertia flywheel as needed.

[0013] Furthermore, the upper and lower ends of the square column section of the rotating rod are both provided with protruding edges; the protruding edges limit the inertia flywheel axially, thereby increasing the connection stability between the inertia flywheel and the rotating rod.

[0014] Preferably, a flange nut is provided under the conductor copper plate; the flange nut comprises a flange plate and a nut body which are coaxially connected; the flange plate is connected to the conductor copper plate through bolts and nuts; the nut body is threadedly matched with the lower end of the rotating rod; the flange nut realizes a detachable connection of the conductor copper plate.

[0015] Preferably, the support frame is mounted on the support to make the overall structure more stable.

[0016] A design method of the above-mentioned adjustable three-element damper for a stay cable comprises the following steps: ① Investigate the wind-induced vibration of the cable and determine the vibration frequency of the cable; ② Determine the stiffness parameter requirements and damping parameter requirements of the adjustable three-element damper of the cable installed on the main beam according to the vibration frequency of the cable; ③ According to the stiffness parameter requirements of the adjustable three-element damper, adjust the inertia coefficient of the inertial 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 both ends of the connecting rod; ④ Design and develop an adjustable three-element damper prototype and conduct mechanical performance tests. The test results show stable performance and reasonable design; ⑤ Carry out various orders of forced vibration tests on model cables and adjustable ternary damper-cable vibration reduction tests.

[0017] The beneficial effects of the present invention are as follows: the adjustable three-element damper for a stay cable of the present invention has the following advantages: (1) The present invention uses the amplification principle of the lever to increase the displacement and velocity input to the damping component, thereby amplifying the inertia parameter, equivalent negative stiffness coefficient, and equivalent damping coefficient of the damping component. This makes the present invention more sensitive to small vibrations and can effectively reduce the vibration amplitude, making it suitable for some high-precision, high-efficiency vibration reduction applications. By changing the connection state between the connecting rod and the lever, the inertia parameter, equivalent negative stiffness coefficient, and equivalent damping coefficient can be adjusted to optimize the vibration reduction performance of the adjustable three-element damper; (2) The present invention connects the magnetic negative stiffness unit, the inertial flywheel and the rotating eddy current damping unit in parallel, giving full play to the coordinated vibration reduction effect of the magnetic negative stiffness unit, the inertial flywheel and the rotating eddy current damping unit, and realizing the amplification effect by adopting the high rotational inertia of the inertial flywheel, thereby increasing the equivalent inertia of the damping component; (3) The inertial flywheel and the rotating rod of the present invention form a detachable structure, which is convenient for replacing the inertial flywheel as needed.

[0018] (4) The adjustable three-dimensional damper for the cable-stayed cable of the present invention has strong adaptability, simple structure, convenient installation, and strong energy dissipation, which solves the difficulties of traditional dampers in terms of space limitation, size, load distribution, installation and maintenance.

[0019] The design method can adjust the inertia parameter, equivalent negative stiffness coefficient and equivalent damping coefficient as needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a stereoscopic diagram of an adjustable three-element damper for a stay cable according to the present invention; Figure 2 yes Figure 1 I magnified view of; Figure 3 yes Figure 1 Side view of Figure 4 yes Figure 3 AA section view; Figure 5 yes Figure 4 II enlarged view; Figure 6 yes Figure 4 BB cross-sectional view; Figure 7 yes Figure 5 CC section view; Figure 8 yes Figure 5 DD cross-sectional view; Fig. 9 yes Figure 5 EE cross-sectional view; Fig.10 It is the comparison between the test value and theoretical value of the axial force time history curve of the adjustable three-element damper; Fig.11 This is a comparison chart between the simulation value and the experimental value of the equivalent inertial mass of the adjustable three-element damper mechanical performance test; Fig.12 It is a comparison chart between the simulation value and the test value of the equivalent negative stiffness coefficient of the adjustable three-element damper mechanical performance test; Fig.13 is the acceleration free decay curve of the measuring point at the mid-span position of the first-order mode of the cable; Fig.14 This is a real-life photo of the adjustable three-element damper; Fig.15 This is a photo of the vibration reduction test of the adjustable three-element damper; In the figure: 11. support, 111. adjustment hole A, 12. lever, 121. adjustment 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. magnetostrictive 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. semicircular disk A, 3311. notch A, 332. semicircular disk B, 3321. notch B, 333. connecting piece, 334. connecting bolt, 335. connecting nut, 34. rotary eddy current damping unit, 341. conductor copper plate, 342. permanent magnet C, 3431. flange, 3432. nut body, 351. sliding rod, 3511. cavity, 352. rotating rod, 3521. square column section, 3522. convex edge. DETAILED DESCRIPTION

[0021] Example 1: See Figure 1-9 , an adjustable three-element damper for a stay cable comprises a receiving component, a sensor 2 and a damping component; The receiving component includes a support 11, a lever 12, a connecting rod 13, and a receiving rod 14; a plurality of adjusting holes A 111 are evenly distributed on the support 11; a plurality of adjusting holes B 121 are evenly distributed in the middle of the lever 12; there are four adjusting holes A 111 and four adjusting holes B 121 in this embodiment; the upper end of the receiving rod 14 is connected to the inclined cable, and the lower end is hinged to the left end of the lever 12; the receiving rod 14 applies the vibration generated by the inclined cable to the left end of the lever 12; the right end of the lever 12 is hinged to the upper end of the sensor 2; the lever 12 applies the vibration to the left end of the lever 12 After the dynamic amplification, it is transmitted to the sensor 2; the sensor 2 detects the force applied to the right end of the lever 12; the two ends of the connecting rod 13 are respectively hinged with the adjusting hole A 111 and the adjusting hole B 121; different combinations of adjusting holes A 111 and adjusting holes B 121 can form magnifications of equivalent negative stiffness coefficients and equivalent damping coefficients with different magnifications; the hinge connection between the lower end of the connecting rod 13 and the adjusting hole B 121 enables the right end of the lever 12 to output vertical reciprocating vibration, which is beneficial to the detection of the sensor 2 and the consumption of vibration by the damping component; The distance from the left end of the adjustment hole 111 of the lever 12 to the hinge point of the lower end of the receiving rod 14 is called the load arm; the distance from the adjustment hole 111 of the lever 12 to the hinge point of the upper end of the sensor 2 is called the force arm; by translating the position of the connecting rod 13 to perform different magnification changes, 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 force arm length to the load arm length, that is, x1 / x2=l1 / l2, among which l1, l2, x1, and x2 are the force arm length, load arm length, vertical displacement of the force arm end, and vertical displacement of the load arm end, respectively.

[0022] According to the principle of conservation of energy, in the lever 12 system, the relationship between the force and length of the lever arm and the load arm end follows the formula: input force × lever arm length = output force × load arm length, that is, f1 × l1 = f2 × l2, where f1 and f2 are input force and output force respectively. Combined with formula k i =f i / x i , k i is the equivalent negative stiffness coefficient, and the equivalent negative stiffness coefficient magnification factor of different connecting rod 13 positions can be obtained respectively. i =f i / v i , the equivalent damping coefficient magnification of different connecting rod 13 positions can be obtained, v i is the axial velocity.

[0023] The adjustment hole 111 where the load arm and the force arm are equal in length is the center position of the lever 12. At this time, the displacement magnification factor is 1, and the equivalent negative stiffness coefficient and the equivalent damping coefficient magnification factors are also 1; the other three adjustment holes 111 are equidistant from each other. According to the above theory, the magnification factors of the equivalent negative stiffness coefficient and the equivalent damping coefficient are respectively the squares of the ratios of the force arm length to the load arm length.

[0024] The damping component includes a support frame, a magnetic negative stiffness unit 32, an inertial flywheel 33, a rotating eddy current damping unit 34 and a transmission assembly; the magnetic negative stiffness unit 32, the inertial flywheel 33 and the rotating eddy current damping unit 34 are sequentially mounted on the support frame; the magnetic negative stiffness unit 32, the inertial flywheel 33 and the rotating eddy current damping unit 34 realize the parallel connection of a three-dimensional vibration reduction configuration, give full play to the coordinated vibration reduction effect of the magnetic negative stiffness unit 32, the inertial flywheel 33 and the rotating eddy current damping unit 34, and increase the equivalent inertia of the damping component by adopting the high rotational inertia amplification effect of the inertial flywheel 33; the transmission assembly vertically penetrates the support frame, and includes a sliding rod 351 and a rotating rod 352; The magnetic negative stiffness unit 32 includes 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 to the support frame and are distributed around the circumference of the transmission component; a permanent magnet A 3231 is arranged on the top of the lifting plate 323; the permanent magnet A 3231 corresponds to the position of the upper permanent magnet 321 and has opposite polarity; a permanent magnet B 3232 is arranged on the bottom of the lifting plate 323; the permanent magnet B 3232 corresponds to the position of the lower permanent magnet 322 and has opposite polarity; The rotary eddy current damping unit 34 includes 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 fixedly connected to the support frame; The top of the sliding rod 351 is connected to the lower end of the sensor 2; the middle part of the sliding rod 351 is vertically slidably matched with the top of the supporting frame; the bottom of the sliding rod 351 is fixedly connected to the top of the lifting plate 323; the bottom of the lifting plate 323 is installed with a ball nut 3233 that is threadedly matched with the upper end of the rotating rod 352; the middle part of the rotating rod 352 is coaxially and detachably connected with the inertial flywheel 33 and the conductor copper plate 341; the lower end of the rotating rod 352 is rotatably connected to the supporting frame. The vertical repetitive vibration transmitted from 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 lift and lower. When the lifting plate 323 rises, the suction force of the upper permanent magnet 321 on the permanent magnet A 3231 is strengthened, and the suction force of the lower permanent magnet 322 on the permanent magnet B 3232 is weakened. When the lifting plate 323 descends, the suction force of the upper permanent magnet 321 on the permanent magnet A 3231 is weakened, and the suction force of the lower permanent magnet 322 on the permanent magnet B 3232 is strengthened. The lifting action of the lifting plate 323 is strengthened and amplified. The lifting plate 323 is connected to the upper and lower parts of the lifting plate 323 by the ball nut. 3233 acts on the rotating rod 352 to rotate the rotating rod 352; the rotating rotating rod 352 acts on most of the vibration energy on the inertial flywheel 33 and converts it into mechanical kinetic energy; the lifting plate 323 rises to drive the inertial flywheel 33 to rotate in the forward direction; the lifting plate 323 descends to drive the inertial flywheel 33 to rotate in the reverse direction, thereby realizing mutual consumption of energy; the rotating rotating rod 352 acts on the conductor copper plate 341; the rotating conductor copper plate 341, under the action of the permanent magnet C 342, realizes eddy current damping to consume the vibration energy transmitted by the inclined cable.

[0025] Compared with the prior art, the present invention uses the amplification principle of the lever 12 to increase the displacement and speed input to the damping component, thereby amplifying the inertia parameter, equivalent negative stiffness coefficient, and equivalent damping coefficient of the damping component, which makes the present invention more sensitive to small vibrations, can effectively reduce the vibration amplitude, and is suitable for some high-precision, high-efficiency vibration reduction applications. By changing the connection state of the connecting rod 13 and the lever 12, the inertia parameter, equivalent negative stiffness coefficient, and equivalent damping coefficient can be adjusted to optimize the vibration reduction performance of the adjustable three-element damper.

[0026] The present invention connects the magnetic negative stiffness unit 32, the inertial flywheel 33 and the rotating eddy current damping unit 34 in parallel, giving full play to the coordinated vibration reduction effect of the magnetic negative stiffness unit 32, the inertial flywheel 33 and the rotating eddy current damping unit 34, and realizing the amplification effect by adopting the high rotational inertia of the inertial flywheel 33, thereby increasing the equivalent inertia of the damping component.

[0027] The upper permanent magnets 321 and the lower permanent magnets 322 are an even number with equal numbers and corresponding positions, so as to ensure the uniformity of the lifting and lowering efficiency enhancement of the lifting plate 323 by the magnetically induced negative stiffness unit 32 .

[0028] 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 at the same time, the magnetic field strength above and below the lifting plate 323 is enhanced; the upper permanent magnet 321 directly above a permanent magnet A 3231 shows opposite attraction to the permanent magnet A 3231; the upper permanent magnets 321 on both sides above the permanent magnet A 3231 show like repulsion to the permanent magnet A 3231; the permanent magnet A 3231 can easily maintain the vertical lifting state; similarly, the permanent magnet B 3232 and the lower permanent magnet 322 can also produce a similar matching relationship; in this way, the overall vertical lifting stability of the lifting plate 323 is improved.

[0029] The positions of permanent magnet A 3231 and permanent magnet B 3232 correspond and their magnetic properties are opposite; permanent magnet A 3231 and permanent magnet B 3232 interact with each other to clamp the lifting plate 323, and the connection relationship between permanent magnet A 3231, permanent magnet B 3232 and the lifting plate 323 is more stable.

[0030] A radial groove 141 is provided in the middle of the lower end of the receiving rod 14; a radial strip 122 extending outward and matching the radial groove 141 is provided at the left end of the lever 12; a hinge hole A is provided in the radial groove 141; the radial strip 122 is provided with a hinge hole B hinged to 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, thereby preventing the axial back-and-forth movement of the sliding shaft of the damping component beyond the safety limit.

[0031] The middle part of the sliding rod 351 is vertically slidably matched with the top of the support frame through the linear bearing 311 to prevent vertical vibration from acting on the support frame, increasing the contact friction between the sliding shaft and the support frame, and damaging the surface of the sliding rod 351 and the support frame.

[0032] The sliding rod 351 and the rotating rod 352 are coaxially arranged, which is beneficial to the transmission of vertical vibration.

[0033] The lower end of the sliding rod 351 is provided with a cavity 3511 which is larger 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, when the sliding shaft moves downward, the top end of the rotating rod 352 is prevented from colliding with the top end of the sliding shaft cavity 3511, causing damage to both, and at the same time making the damping component structure more compact.

[0034] A square column section 3521 is provided in the middle of the rotating rod 352; the inertia flywheel 33 is in the shape of a disk as a whole, including a semi-disc A 331, a semi-disc B 332, a connecting piece 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 in the center corresponding to the square column section 3521; the notch A 3311 and the notch B 3321 cooperate with each other to form a limit connection with the square column section 3521 to prevent the inertia flywheel 33 from being entangled with the rotating rod The outer wall of 352 rotates and slips when rotating together; there are at least two connecting pieces 333, which are arranged on both sides of the square column section 3521; the bottom of the connecting piece 333 is connected with the semicircular disk A 331 and the semicircular disk B 332; the end of the connecting bolt 334 is threadedly connected with the connecting nut 335; the middle of the connecting bolt 334 passes through the semicircular disk A 331 / semicircular disk B 332 and the connecting piece 333; the inertial flywheel 33 and the rotating rod 352 form a detachable structure, which is convenient for replacing the inertial flywheel 33 as needed. There are two connecting pieces 333 in this embodiment.

[0035] The upper and lower ends of the square column section 3521 of the rotating rod 352 are both extended with convex edges 3522; the convex edges 3522 axially limit the inertia flywheel 33, thereby increasing the connection stability between the inertia flywheel 33 and the rotating rod 352.

[0036] A flange nut is provided below the conductor copper plate 341; the flange nut comprises a coaxially connected flange 3431 and a nut body 3432; the flange 3431 is connected to the conductor copper plate 341 through bolts and nuts 315; the nut body 3432 is threadedly matched with the lower end of the rotating rod 352; the flange nut realizes a detachable connection of the conductor copper plate 341.

[0037] The supporting 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 to the bottom of the upper top plate 3121; the lower permanent magnet 322 is connected to the top of the upper bottom plate 3122; the upper support column 3123 is distributed around the circumference of the transmission component, 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 rotatably connected to the lower bottom plate 3142; the lower support column 3143 is distributed around the circumference of the transmission component, 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 distributed around the circumference of the transmission component, connecting the upper bottom plate 3122 and the lower top plate 3141.

[0038] After the upper end of the upper support column 3123 passes through the upper top plate 3121, it is threadedly engaged with a nut 315; a threaded hole 31231 is coaxially provided at the lower end of the upper support column 3123; an upper threaded section 31311 threadedly engaged with the threaded hole 31231 is provided at the upper end of the middle support column 3131; a lower threaded section 31312 is provided at the lower end of the middle support column 3131; the lower threaded section 31312 passes through the lower top plate 3141 and is threadedly engaged with a nut 315.

[0039] The lower top plate 3141 is installed with a thrust bearing 31421 ; the thrust bearing 31421 is connected to the rotating rod 352 .

[0040] Embodiment 2: Embodiment 2 is basically the same as Embodiment 1, and the similarities are not repeated here. The differences are: the support frame is installed on the support 11 to make the overall structure more stable; the support frame is connected to the support 11 as a whole and can be directly installed on the main body of the building.

[0041] Example 3: See Figure 10-13 A design method of an adjustable three-element damper for a stay cable according to Embodiment 1 comprises the following steps: ① Investigate the wind-induced vibration of the cable and determine the vibration frequency of the cable; ② Determine the stiffness parameter requirements and damping parameter requirements of the adjustable three-element damper of the cable installed on the main beam according to the vibration frequency of the cable; ③ According to the stiffness parameter requirements of the adjustable three-element damper, adjust the inertia coefficient of the inertial flywheel 33, the number of permanent magnet groups of the magnetic negative stiffness unit 32 and the rotary eddy current damping unit 34, and the hinge positions at both ends of the connecting rod 13.

[0042] ④ Design and develop an adjustable three-element damper prototype and conduct mechanical performance tests. The test results show that the performance is stable and the design is reasonable.

[0043] See also Fig.10It can be concluded that the relative errors between the simulation value and the test value of the mechanical properties test of the ternary damper are within 15%. The results show that the design method of the ternary damper developed here is correct, the parameters are stable, and the performance is good.

[0044] ⑤ Carry out 1st, 2nd and 3rd order forced vibration tests on model cables and adjustable ternary damper-cable vibration reduction tests.

[0045] After the exciter is turned off, the cable enters a free decay vibration state. Fig.13 The acceleration free decay curve of the first-order mode of the cable at the mid-span position is given by Fig.13 It can be seen that the vibration acceleration of the cable under each working condition shows a typical logarithmic attenuation law; the first-order modal damping ratio of the cable increases from 0.09% (uncontrolled) to 1.71% (adjustable one-element damper control), to 2.25% (adjustable two-element damper control), and further increases to 3.10% (adjustable three-element damper control). The analysis of the test results of adjustable three-element damper-cable vibration reduction verifies the vibration reduction effect of the adjustable three-element damper-cable and the feasibility of the design method of adjustable three-element damper for cable vibration reduction.

Claims

1. An adjustable three-element damper for a stay cable, characterized in that: It includes a receiving component, a sensor and a damping component; The receiving component includes a support, a lever, a connecting rod, and a receiving rod; a plurality of adjusting holes A are evenly distributed horizontally on the support; a plurality of adjusting holes B are evenly distributed horizontally in the middle of the lever; 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 the adjusting hole A and the adjusting hole B; The damping component includes a support frame, a magnetic negative stiffness unit, an inertial flywheel, a rotary eddy current damping unit and a transmission assembly; the magnetic negative stiffness unit, the inertial flywheel and the rotary eddy current damping unit are sequentially mounted on the support frame; the transmission assembly vertically penetrates the support frame and includes a sliding rod and a rotating rod; The magnetic negative stiffness unit includes an upper permanent magnet, a lower permanent magnet, and a lifting plate; the upper permanent magnet and the lower permanent magnet are both fixedly connected to the support frame and are distributed around the circumference of the transmission component; a permanent magnet A is arranged on the top of the lifting plate; the permanent magnet A corresponds to the position of the upper permanent magnet and has an opposite polarity; a permanent magnet B is arranged on the bottom of the lifting plate; the permanent magnet B corresponds to the position of the lower permanent magnet and has an opposite polarity; The rotary eddy current damping unit comprises 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, fixedly connected 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 matched with the top of the supporting frame; the bottom of the sliding rod is fixedly connected to the top of the lifting plate; a ball nut that matches the thread of the upper end of the rotating rod is installed at the bottom of the lifting plate; the middle of the rotating rod is coaxially and detachably connected with the inertia flywheel and the conductor copper plate; the lower end of the rotating rod is rotatably connected to the supporting frame.

2. The adjustable three-element damper for a stay cable according to claim 1, characterized in that: A radial groove is provided in 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 on the radial strip hinged 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. The adjustable three-element damper for a stay cable according to claim 1, characterized in that: The middle part of the sliding rod is vertically slidably matched with the top of the supporting frame through a linear bearing.

4. The adjustable three-element damper for a stay cable according to claim 1, characterized in that: The sliding rod is coaxially arranged with the rotating rod.

5. The adjustable three-element damper for a stay cable according to claim 4, characterized in that: 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.

6. The adjustable three-element damper for a stay cable according to claim 1, characterized in that: A square column section is arranged in the middle of the rotating rod; the inertia flywheel is in the shape of a disc as a whole, and comprises a semi-disc A, a semi-disc B, a connecting plate, a connecting bolt and a connecting nut; the semi-disc A and the semi-disc B are respectively provided with a notch A and a notch B matching the square column section at the center; there are at least two connecting plates, which are arranged on both sides of the square column section; the bottom of the connecting plate is connected with the semi-disc A and the semi-disc B; the end of the connecting bolt is threadedly connected with the connecting nut; the middle of the connecting bolt passes through the semi-disc A / semi-disc B and the connecting plate.

7. The adjustable three-element damper for a stay cable according to claim 6, characterized in that: The upper and lower ends of the square column section of the rotating rod are both provided with convex edges extending outwards.

8. The adjustable three-element damper for a stay cable according to claim 1, characterized in that: A flange nut is arranged below the conductor copper plate; the flange nut comprises a flange plate and a nut body which are coaxially connected; the flange plate is connected to the conductor copper plate through bolts and nuts; and the nut body is threadedly matched with the lower end of the rotating rod.

9. The adjustable three-element damper for a stay cable according to claim 1, characterized in that: The supporting frame is mounted on the support.

10. A design method for an adjustable three-element damper for a stay cable according to claim 1, characterized in that: The following steps are involved: ① Investigate the wind-rain-induced vibration conditions of the cable and determine the vibration frequency of the cable; ② Determine the stiffness parameter requirements and damping parameter requirements of the adjustable three-element damper of the cable installed on the main beam according to the vibration frequency of the cable; ③ According to the stiffness parameter requirements of the adjustable three-element damper, adjust the inertia coefficient of the inertial 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 both ends of the connecting rod; ④ Design and develop an adjustable three-element damper prototype and conduct mechanical performance tests; ⑤ Carry out various orders of forced vibration tests on model cables and adjustable ternary damper-cable vibration reduction tests.

Images