Multiple eddy current tuned mass damper suitable for inhaul cable multi-mode vortex vibration control

Abstract

The invention discloses a multi-eddy current tuned mass damper suitable for inhaul cable multi-mode vortex vibration control. The multi-eddy current tuned mass damper is composed of a frequency modulation mass system and two damping-adjustable plate type eddy current damping systems. Wherein the frequency modulation mass system is composed of a main steel strand, two main mass blocks, two auxiliary steel strands and four auxiliary mass blocks; the plate-type eddy current damper comprises a permanent magnet group fixed on a mass block of the frequency modulation mass system, a conductor copper plate, an L-shaped magnetic steel plate for adjusting a gap between a permanent magnet and the conductor copper plate, and an eddy current damper cable clamp. The vibration frequency and the damping ratio of each mass block of the frequency modulation mass system are continuously adjustable, and the mass blocks can be assembled on site. Due to the fact that the frequency modulation mass system comprises six mass blocks and has six tuning frequencies, efficient control over multi-mode vortex vibration of the stay cable can be achieved through the multiple eddy current tuned mass damper, in addition, the frequency and damping of all the tuned mass damper elements are continuously adjustable, and optimal control over the stay cable can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of vibration control of inclined cables, and in particular relates to a multiple eddy current tuned mass damper suitable for multi-modal vortex vibration control of cables. Background Art

[0002] Cables are the main load-bearing components of cable-stayed bridges. However, cables are very prone to multi-modal vortex vibration under the action of wind. Since 2018, vortex vibration of cables has been reported on many large-span cable-stayed bridges in my country. For example, the NA09U, NA29U, NA30U and NA31U cables of the Sutong Bridge have all experienced high-order vortex vibration, among which the RMS acceleration per minute of NA30U is close to 15m / s 2 The maximum vibration frequency is 12.30Hz (corresponding to the 47th mode of the cable); the maximum vortex vibration acceleration of the JB01 cable of the Jingyue Yangtze River Bridge reaches 25m / s 2 , the vortex vibration mode order is 12 to 14. The high-order vortex vibration of the cable will not only cause fatigue damage to the cable and shorten the fatigue life of the cable, but also cause the cable damper connector to be damaged, resulting in the failure of the damper to control the wind-rain vibration of the cable.

[0003] In order to effectively control the multi-modal high-order vortex vibration of the cable, the patent "A cable vibration reduction device for a cable-stayed bridge" proposes to install a large-mass tuned mass damper on the cable to control the cable vibration. However, the control frequency of the device is relatively single, and the tuned mass damper uses a spring as an elastic element, and the frequency and damping are difficult to adjust; the patents "A combined vibration reduction device and method for a cable" and "A collision-type vibration reduction hammer for a bridge cable" propose to use an anti-vibration hammer to suppress the high-order vortex vibration of the cable, but the anti-vibration hammer only includes 4 main frequencies, and the frequency and damping ratio of the anti-vibration hammer are difficult to adjust, making it difficult to achieve optimal control of the multi-modal vibration reduction of the cable. The patent "A multi-directional multi-tuned mass damper for cable structure vibration reduction" proposes to use multiple anti-vibration hammers to suppress the multi-modal vortex vibration of the cable structure, but the damping parameters of each anti-vibration hammer are completely provided by the steel strand, and the damping is difficult to adjust, and the optimal control of the tuned mass damper cannot be achieved. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of limited control modes, difficult frequency and damping adjustment, and low durability of the damping system of the existing vortex vibration control device of the inclined cable, and to provide a multi-eddy current tuned mass damper suitable for multi-mode vortex vibration control of the cable;

[0005] In order to achieve the above-mentioned object, the present invention adopts the following technical scheme: a multiple eddy current tuned mass damper suitable for multi-modal vortex vibration control of a cable, comprising: a cable clamp, a connecting plate, a steel strand fixing clamp, a main frequency modulation mass system, a secondary frequency modulation mass system, a plate-type eddy current damping system, and a cable clamp connecting the plate-type eddy current damping system;

[0006] The plate-type eddy current damping system is installed on the inclined cable through the plate-type eddy current damping system connecting cable clamp, and is connected to the main frequency modulation mass system through the auxiliary frequency modulation mass system respectively. The steel strand fixing clamp is arranged on the main frequency modulation mass system, and the steel strand fixing clamp is connected to the cable clamp through a connecting plate. The cable clamp is arranged at the vibration amplitude of the main frequency mode of vortex vibration of the inclined cable or the maximum allowable installation height.

[0007] Further, the main frequency modulation mass system includes: a main stranded wire, two main mass blocks and a first bolt group;

[0008] The steel strand fixing clamp is connected to the main strand, and oblong holes are provided on the two main mass blocks. The two ends of the main strand are respectively inserted into the two main mass blocks through the oblong holes, and are fixed to the two main mass blocks by a first bolt group. Through holes are provided on the sides of the two main mass blocks for connecting the auxiliary frequency modulation mass system.

[0009] Further, the auxiliary frequency modulation mass system comprises: an auxiliary stranded wire, two auxiliary mass blocks, a second bolt group and a third bolt group;

[0010] The auxiliary stranded wire passes through the through hole on the side of the main mass block and is fixed to the main mass block through the second bolt group. The two auxiliary mass blocks are fixed to the two ends of the auxiliary stranded wire through the third bolt group.

[0011] Furthermore, the mass of the main mass block is greater than the mass of the secondary mass block.

[0012] Furthermore, the plate-type eddy current damping system comprises: a permanent magnet group, a conductor copper plate and an L-shaped magnetic steel plate;

[0013] The permanent magnet groups are respectively arranged on the main mass block and the auxiliary mass block, the L-shaped magnetic steel plate is installed on the plate-type eddy current damper connecting cable clamp through the fourth bolt group, and a straight slot hole is opened on the L-shaped magnetic steel plate, and the conductor copper plate is installed on the L-shaped magnetic steel plate.

[0014] Furthermore, in the vibration direction of the inclined cable, the permanent magnet poles of the permanent magnet group are arranged oppositely, and the permanent magnet spacing is half of the side length of the permanent magnet. In the direction perpendicular to the vibration direction of the inclined cable, the permanent magnet poles of the permanent magnet group are arranged identically, and the permanent magnet spacing should not exceed 0.1 times the side length of the permanent magnet.

[0015] Beneficial effect: by adjusting the main frequency-modulating mass system and the auxiliary frequency-modulating mass system, the damper generates multiple vibration frequencies tuned to the vibration modes of the inclined cable, and at the same time, the plate-type eddy current damping system is adjusted to make the damper produce different damping ratios, thereby realizing effective control of multi-modal high-order vortex vibrations of the inclined cable, and the frequency and damping ratio of the damper of the present invention are continuously adjustable, which can achieve optimal control of multi-modal high-order vortex vibrations of the inclined cable, and the various parts of the damper are connected by bolt groups, which is convenient for on-site assembly. At the same time, the installation position of the damper of the present invention is located at the anchor end of the inclined cable only on the bridge deck, and no mounting bracket is required, so the installation is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0017] Figure 2 It is a schematic diagram of the structure of the main frequency modulation quality system of the present invention.

[0018] Figure 3 It is a schematic diagram of the installation structure of the permanent magnet group of the auxiliary frequency modulation mass system and the plate-type eddy current damping system of the present invention.

[0019] Figure 4 The present invention is a schematic diagram of the installation structure of the plate-type eddy current damping system connecting the cable clamp, the L-shaped magnetic steel plate, and the conductor copper plate.

[0020] Figure 5 It is a schematic diagram of the cable clamp structure of the plate-type eddy current damping system of the present invention.

[0021] Figure 6 The figure is a schematic diagram of an L-shaped magnetic steel plate of the plate-type eddy current damping system of the present invention.

[0022] In the figure: 1. inclined cable, 2. cable clamp, 201. fifth bolt group, 3. connecting plate, 4. steel strand fixing clamp, 401. sixth bolt group, 5. main frequency modulation mass system, 501. main strand, 502. main mass block, 503. first bolt group, 6. auxiliary frequency modulation mass system, 601. auxiliary strand, 602. auxiliary mass block, 603. second bolt group, 604. third bolt group, 7. plate-type eddy current damping system, 701. permanent magnet group, 702. conductor copper plate, 703. L-shaped magnetic steel plate, 704. straight slot hole, 705. fourth bolt group, 8. plate-type eddy current damping system connecting cable clamp. DETAILED DESCRIPTION

[0023] The present invention will be further explained below in conjunction with the accompanying drawings.

[0024] like Figure 1As shown, a multiple eddy current tuned mass damper suitable for multi-modal vortex vibration control of a cable is characterized in that it includes: a cable clamp 2, a connecting plate 3, a steel strand fixing clamp 4, a main frequency modulation mass system 5, two auxiliary frequency modulation mass systems 6, two plate-type eddy current damping systems 7 and two plate-type eddy current damping system connecting cable clamps 8;

[0025] Two auxiliary frequency modulation mass systems 6, two plate-type eddy current damping systems 7 and two plate-type eddy current damping system connecting cable clamps 8 are respectively located on the left and right sides of the cable clamp 2. The plate-type eddy current damping system 7 on the left is installed on the left side of the inclined cable 1 through the plate-type eddy current damping system connecting cable clamp 8 on the left, and is respectively connected to the left side of the main frequency modulation mass system 5 through the auxiliary frequency modulation mass system 6 on the left. The plate-type eddy current damping system 7 on the right is installed on the right side of the inclined cable 1 through the plate-type eddy current damping system connecting cable clamp 8 on the right, and is respectively connected to the right side of the main frequency modulation mass system 5 through the auxiliary frequency modulation mass system 6 on the right. The steel strand fixing clamp 4 is arranged on the main frequency modulation mass system 5, and the steel strand fixing clamp 4 is connected to the cable clamp 2 through the connecting plate 3. The cable clamp 2 is fixed to the vibration amplitude of the vortex vibration main frequency mode of the inclined cable 1 or the maximum allowable installation height through the fifth bolt group 201.

[0026] In this embodiment, when the cable 1 has adopted a damper to control wind-rain vibration, the multiple eddy current tuned mass damper of the present invention is preferably installed near the midpoint between the damper and the anchor point of the cable.

[0027] like Figure 2 As shown, the main frequency modulation mass system 5 includes: a main strand 501, two main mass blocks 502 and a first bolt group 503;

[0028] The steel strand fixing clamp 4 is fixed to the main strand 501 by the sixth bolt group. Long circular holes are opened on the two main mass blocks 502 and are located on the left and right sides of the steel strand fixing clamp 4. The two ends of the main strand 501 pass through the long circular holes and penetrate into the main mass block 502 on the left and the main mass block 502 on the right respectively, and are fixed to the main mass block 502 on the left and the main mass block 502 on the right by the first bolt group 503. Through holes are opened on the sides of the main mass block 502 on the left and the main mass block 502 on the right for connecting the two auxiliary frequency modulation mass systems 6.

[0029] like Figure 3 As shown, the two auxiliary frequency modulation mass systems 6 each include: an auxiliary stranded wire 601, two auxiliary mass blocks 602, a second bolt group 603 and a third bolt group 604;

[0030] In the sub-frequency modulation mass system 6 on the left: the sub-stem strand 601 on the left passes through the through hole on the side of the main mass block 502 on the left, and is fixed to the main mass block 502 on the left by the second bolt group 603, and the two sub-mass blocks 602 are fixed to the upper and lower ends of the sub-stem strand 601 on the left by the third bolt group 604.

[0031] In the sub-frequency modulation mass system 6 on the right side: the sub-stem strand 601 on the right side passes through the through hole on the side of the main mass block 502 on the right side, and is fixed to the main mass block 502 on the right side by the second bolt group 603, and the two sub-mass blocks 602 are fixed to the upper and lower ends of the sub-stem strand 601 on the right side by the third bolt group 604.

[0032] In this embodiment, the two main mass blocks 502 can slide along the main strand 501 before the first bolt group 503 is fixed, and the two auxiliary mass blocks 602 can slide along the auxiliary strand 601 before the third bolt group 604 is fixed. The mass of the main mass block 502 is greater than the mass of the auxiliary mass block 602.

[0033] like Figure 4-6 As shown, the two plate-type eddy current damping systems 7 both include: a permanent magnet group 701, a conductor copper plate 702 and an L-shaped magnetic steel plate 703;

[0034] In the plate-type eddy current damping system 7 on the left: the permanent magnet group 701 on the left is respectively arranged on the main mass block 502 on the left and the two auxiliary mass blocks 602 of the auxiliary frequency-modulated mass system 6 on the left, the L-shaped magnetic steel plate 703 on the left is installed at the bottom of the plate-type eddy current damper connecting cable clamp on the left through the fourth bolt group 705, and a straight slot hole 704 is opened on the L-shaped magnetic steel plate 703 on the left, and the conductor copper plate 702 on the left is installed on the L-shaped magnetic steel plate 703 on the left.

[0035] In the plate-type eddy current damping system 7 on the right: the permanent magnet group 701 on the right is respectively arranged on the main mass block 502 on the right and the two auxiliary mass blocks 602 of the auxiliary frequency-modulated mass system 6 on the right, the L-shaped magnetic steel plate 703 on the right is installed at the bottom of the plate-type eddy current damper connecting cable clamp on the right through the fourth bolt group 705, and a straight slot hole 704 is opened on the L-shaped magnetic steel plate 703 on the right, and the conductor copper plate 702 on the right is installed on the L-shaped magnetic steel plate 703 on the left.

[0036] In this embodiment, before installing the fourth bolt group 705, the L-shaped magnetic steel plate 703 should be able to move along the axial direction of the inclined cable 1, the permanent magnet group 701 is in the vibration direction of the inclined cable 1, the permanent magnet poles are arranged oppositely, and the permanent magnet spacing is half of the side length of the permanent magnet, the permanent magnet group 701 is perpendicular to the vibration direction of the inclined cable 1, the permanent magnet poles are arranged in the same way, and the permanent magnet spacing should not be greater than 0.1 times the side length of the permanent magnet.

[0037] by Figure 3 For reference, the multi-tuned mass damper for multi-modal vortex vibration control of the cable in this embodiment includes 6 tuning frequencies, namely:

[0038] The effective vibration mass of the first tuning frequency includes the main mass block 502 on the left and two auxiliary mass blocks 602 of the auxiliary frequency tuning mass system 6 on the left, and the frequency is adjusted by the distance between the center of mass position of the three mass blocks and the steel strand fixing clamp 4;

[0039] The effective vibration mass of the second tuning frequency includes the main mass block 502 on the right side and two auxiliary mass blocks 602 of the auxiliary frequency tuning mass system 6 on the right side, and the frequency is adjusted by the distance between the center of mass position of the three mass blocks and the steel strand fixing clamp 4;

[0040] The effective vibration mass of the third tuning frequency is determined by the auxiliary mass block 602 on the lower side of the auxiliary frequency-modulated mass system 6 on the left, and the frequency is adjusted by the distance between the center of mass of the auxiliary mass block 602 on the lower side of the auxiliary frequency-modulated mass system 6 on the left and the lower side edge of the main mass block 502 on the left;

[0041] The effective vibration mass of the fourth tuning frequency is determined by the auxiliary mass block 602 on the lower side of the auxiliary frequency-modulated mass system 6 on the right side, and the frequency is adjusted by the distance between the center of mass of the auxiliary mass block 602 on the lower side of the auxiliary frequency-modulated mass system 6 on the right side and the lower side edge of the main mass block 502 on the right side;

[0042] The effective vibration mass of the fifth tuning frequency is determined by the auxiliary mass block 602 on the upper side of the auxiliary frequency-modulated mass system 6 on the left, and the frequency is adjusted by the distance between the center of mass of the auxiliary mass block 602 on the upper side of the auxiliary frequency-modulated mass system 6 on the left and the upper side edge of the main mass block 502 on the left;

[0043] The effective vibration mass of the sixth tuning frequency is determined by the auxiliary mass block 602 on the upper side of the auxiliary frequency-modulated mass system 6 on the right, and the frequency is adjusted by the distance between the center of mass of the auxiliary mass block 602 on the upper side of the auxiliary frequency-modulated mass system 6 on the right and the upper side edge of the main mass block 502 on the right.

[0044] by Figure 3 For reference, the damping ratio adjustment method of each tuning frequency of the multiple tuned mass damper applicable to multi-mode vortex vibration control of the inclined cable in this embodiment includes:

[0045] The damping ratio of the tuned mass damper corresponding to the first tuning frequency is adjusted substantially by adjusting the static spacing between the left conductor copper plate 702 and the left permanent magnet group 701, and then fine-tuned by the number of permanent magnets of the left mass block 502;

[0046] The damping ratio of the tuned mass damper corresponding to the second tuning frequency is substantially adjusted by adjusting the static spacing between the conductor copper plate 702 on the right and the permanent magnet group 701 on the right, and then fine-tuned by the number of permanent magnets on the mass block 502 on the right;

[0047] The damping ratio of the tuned mass damper corresponding to the third tuning frequency is adjusted by the number of permanent magnets on the auxiliary mass block 602 on the lower side of the auxiliary frequency tuning mass system 6 on the left side;

[0048] The damping ratio of the tuned mass damper corresponding to the fourth tuning frequency is adjusted by the number of permanent magnets on the auxiliary mass block 602 on the lower side of the auxiliary frequency tuning mass system 6 on the right side;

[0049] The damping ratio of the tuned mass damper corresponding to the fifth tuning frequency is adjusted by the number of permanent magnets on the auxiliary mass block 602 on the upper side of the auxiliary frequency tuning mass system 6 on the left side;

[0050] The damping ratio of the tuned mass damper corresponding to the sixth tuning frequency is adjusted by the number of permanent magnets on the auxiliary mass block 602 on the upper side of the auxiliary frequency-tuned mass system 6 on the right side.

[0051] The working principle of this embodiment is as follows:

[0052] According to the measured vortex-vibration mode of the cable, the mass of each mass block of the multiple eddy current tuned mass damper, the frequency and damping ratio of the main frequency-modulated mass system and the auxiliary frequency-modulated mass system are designed; the multiple eddy current tuned mass damper is installed at the predetermined position of the cable, and the frequency and damping ratio of the main frequency-modulated mass system and the auxiliary frequency-modulated mass system are adjusted to the optimal design value. When the cable 1 vibrates, the vibration of the cable will drive the main frequency-modulated mass system and the auxiliary frequency-modulated mass system of the multiple eddy current tuned mass damper to vibrate. Since the vibration control force of each tuned mass damper is opposite to the vibration direction of the cable, the vibration of the cable is reduced. In addition, the additional damping generated by the multiple eddy current tuned mass damper on the cable can offset the pneumatic negative damper of the vortex-vibration of the cable, thereby preventing the occurrence of vortex-vibration of the cable.

[0053] The present invention adjusts the main frequency-modulating mass system and the auxiliary frequency-modulating mass system so that the damper generates multiple different frequencies, and simultaneously adjusts the plate-type eddy current damping system so that the damper generates different damping ratios, thereby achieving effective control of multi-modal high-order vortex vibrations of the inclined cable. The frequency and damping ratio of the damper of the present invention are continuously adjustable, and optimal control of multi-modal high-order vortex vibrations of the inclined cable can be achieved. The various parts of the damper are connected by a bolt group, which is convenient for on-site assembly. At the same time, the installation position of the damper of the present invention is located at the anchor end of the inclined cable only on the bridge deck, and no mounting bracket is required, so the installation is more convenient.

[0054] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multiple eddy current tuned mass damper suitable for multi-mode vortex vibration control of cables, characterized in that: include: A cable clamp (2), a connecting plate (3), a steel strand fixing clamp (4), a main frequency modulation mass system (5), a secondary frequency modulation mass system (6), a plate-type eddy current damping system (7), and a cable clamp (8) connecting the plate-type eddy current damping system; The plate-type eddy current damping system (7) is installed on the inclined cable (1) via a plate-type eddy current damping system connecting cable clamp (8), and is connected to the main frequency modulation mass system (5) via a secondary frequency modulation mass system (6), the steel strand fixing clamp (4) is arranged on the main frequency modulation mass system (5), the steel strand fixing clamp (4) is connected to the cable clamp (2) via a connecting plate (3), and the cable clamp (2) is arranged at the vibration amplitude of the vortex vibration main frequency mode of the inclined cable (1) or at the maximum allowable installation height.

2. The multiple eddy current tuned mass damper suitable for multi-modal vortex vibration control of cables according to claim 1, characterized in that: The main frequency modulation mass system (5) comprises: a main strand (501), two main mass blocks (502) and a first bolt group (503); The steel strand fixing clamp (4) is connected to the main strand (501), and oblong holes are provided on the two main mass blocks (502). The two ends of the main strand (501) are respectively inserted into the two main mass blocks (502) through the oblong holes, and are fixed to the two main mass blocks (502) through the first bolt group (503). Through holes are provided on the sides of the two main mass blocks (502) for connecting the auxiliary frequency modulation mass system (6).

3. The multiple eddy current tuned mass damper suitable for multi-modal vortex vibration control of cables according to claim 2, characterized in that: The auxiliary frequency modulation mass system (6) comprises: an auxiliary stranded wire (601), two auxiliary mass blocks (602), a second bolt group (603) and a third bolt group (604); The secondary strand (601) passes through the through hole on the side of the main mass block (502) and is fixed to the main mass block (502) by a second bolt group (603). The two secondary mass blocks (602) are fixed to the two ends of the secondary strand (601) by a third bolt group (604).

4. The multiple eddy current tuned mass damper suitable for multi-modal vortex vibration control of cables according to claim 3 is characterized in that: The mass of the main mass block (502) is greater than the mass of the secondary mass block (602).

5. The multiple eddy current tuned mass damper suitable for multi-modal vortex vibration control of cables according to claim 3, characterized in that: The plate-type eddy current damping system (7) comprises: a permanent magnet group (701), a conductor copper plate (702) and an L-shaped magnetic steel plate (703); The permanent magnet groups (701) are respectively arranged on the main mass block (502) and the auxiliary mass block (602); the L-shaped magnetic steel plate (703) is installed on the plate-type eddy current damper connecting cable clamp via a fourth bolt group (705); a straight slot hole (704) is provided on the L-shaped magnetic steel plate (703); and the conductor copper plate (702) is installed on the L-shaped magnetic steel plate (703).

6. The multiple eddy current tuned mass damper suitable for multi-modal vortex vibration control of cables according to claim 5, characterized in that: The permanent magnet group (701) has magnetic poles arranged opposite to each other in the vibration direction of the inclined cable (1), and the spacing between the permanent magnets is half the length of the permanent magnet side. The permanent magnet group (701) has magnetic poles arranged identically in a direction perpendicular to the vibration direction of the inclined cable (1), and the spacing between the permanent magnets should not exceed 0.1 times the length of the permanent magnet side.

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