A hysteretic damping type auxiliary cable using inerter

Abstract

The application belongs to the technical field of engineering structure vibration control, and particularly relates to a kind of inertia hysteresis damping type auxiliary cable, including inertia hysteresis damping device, auxiliary cable and connecting cable clamp assembly. Inertia hysteresis damping device is composed of outer frame, rubber damping element, inner box, ball screw, rotating mass and connecting clamp. Auxiliary cable adopts steel strand. Inertia hysteresis damping device is connected with cable clamp through rotating shaft, and finally connected with stay cable. Inertia hysteresis damping type auxiliary cable provided by the application adopts the form of shear type high damping rubber damper and parallel inertia container. High damping rubber damper has the characteristics of large stiffness and no liquid substance, so it is easy to combine with auxiliary cable. Inertia container can amplify displacement and effectively improve the additional damping provided by damper. Inertia hysteresis damping type auxiliary cable provided by the application can better control the broadband multi-mode vibration of super-long cable-stayed cable.

Description

Technical Field

[0001] This invention belongs to the field of vibration control technology for engineering structures, specifically relating to a cable-stayed bridge cable vibration reduction device formed by a combination of an inertial capacitive hysteresis damping device and a steel strand auxiliary cable. Background Technology

[0002] Due to their low inherent damping, low mass per unit length, and low lateral stiffness, stay cables are highly susceptible to vibration problems caused by external loads, such as wind and rain vibration and vortex-induced vibration. Common vibration reduction measures for stay cables include aerodynamic devices, dampers, and auxiliary cables. Practice has shown that these measures can generally meet the vibration reduction requirements for medium- and short-length stay cables (below 300m). However, vibration reduction for ultra-long stay cables remains a challenging problem in stay cable vibration control.

[0003] Traditional vibration reduction measures are no longer sufficient to meet the vibration reduction requirements of long-span cable-stayed bridges, and vibration reduction of ultra-long cable-stayed bridges faces new challenges: cable-stayed bridge vibration exhibits multi-mode and multi-mechanism characteristics. The fundamental frequency of ultra-long cable-stayed bridges has dropped to around 0.2Hz, and the number of low-order wind and rain vibration control modes (usually below 3Hz) is as high as 13. Even after installing cable-end dampers, high-frequency vortex-induced vibration still occurs, with frequencies reaching above 10Hz; the shortcomings of traditional vibration reduction measures are becoming increasingly apparent. Aerodynamic vibration reduction measures have been proven to have limited effectiveness in numerous practical applications. The installation height of dampers is limited, especially for cable-stayed bridges anchored with anchor plates. Furthermore, the frequency-dependent performance parameters of dampers make it difficult to meet the wide-frequency-range vibration reduction requirements of ultra-long cable-stayed bridges. In addition, damper measures suffer from a "vibration control blind spot" problem located at the stagnation point of the vibration mode. Traditional auxiliary cable measures introduce insufficient damping, leading to localized cable segment vibrations in the cable net system.

[0004] Current aerodynamic and damping measures are insufficient to effectively address the vibration problems of ultra-long cable-stayed bridges. Damped auxiliary cable measures may become an unavoidable vibration reduction measure for long-span cable-stayed bridges. Against this backdrop, this invention, considering the vibration characteristics of ultra-long cable-stayed bridges and the advantages and disadvantages of traditional vibration reduction measures, proposes an inertial-capacitive hysteretic damping auxiliary cable device. In installation, the auxiliary cable (steel strand) is fixed to the back cable, tensioned, and anchored to the bridge tower, main beam, or inner cable. Then, an inertial-capacitive hysteretic damping device is installed at the intersection of the auxiliary cable and the cable. Structurally, the inertial-capacitive hysteretic damping auxiliary cable refers to the installation of an inertial-capacitive hysteretic damping device at the overlap between the traditional auxiliary cable and the cable. The inertial-capacitive hysteretic damping device adopts a parallel inertial container form of a shear-type high-damping rubber damper. The high-damping rubber damper has characteristics such as high stiffness and no liquid substances, therefore, it is easily integrated with the auxiliary cable. Inertial containers can overcome the limitations of inertial mass units in terms of mass and size in engineering practice, achieving higher mass efficiency. Inertial containers can amplify displacement, effectively enhancing the additional damping provided by dampers. This invention proposes an inertial capacitive hysteretic damping auxiliary cable vibration reduction device, which is expected to better control the wide-frequency multimodal vibration of ultra-long cable-stayed cables. Summary of the Invention

[0005] This invention addresses the challenge of traditional auxiliary cables failing to improve the damping of cable-stayed bridge systems by proposing a cable-stayed bridge cable vibration reduction device formed by combining an inertial-capacitive hysteretic damping device with a steel strand auxiliary cable. The damping-type auxiliary cable of this invention increases the system's damping margin by installing an inertial-capacitive hysteretic damping device at the intersection of the auxiliary cable and the cable, utilizing the damping enhancement mechanism of the inertial container to achieve a comprehensive improvement in the multi-modal damping and frequency of the cable-stayed bridge.

[0006] The technical solution of the present invention is described as follows:

[0007] An inertial-capacitive hysteresis damping type auxiliary cable, comprising a high-damping rubber damper connected in parallel with an inertial container device at the junction of the auxiliary cable and the tension cable, including an inertial-capacitive hysteresis damping device, an auxiliary cable, and connecting cable clamps. The high-damping rubber damper connected in parallel with the inertial container device is installed at the junction of the auxiliary cable and the tension cable. The inertial-capacitive hysteresis damping device includes an outer frame, an inner box, rubber damping elements, ball screws, a rotating mass block, and connecting clamps. The rubber damping elements are symmetrically installed between the outer frame and the inner box. The screw is fixed to the bottom of the outer frame and passes through the interior of the inner box. The rotating mass block passes through the screw and is connected to the inner box via ball screws on its top and bottom surfaces. Connecting clamps are provided on both sides of the outer frame for fixing the auxiliary cable.

[0008] Preferably, the auxiliary cable is made of steel strand.

[0009] Preferably, the rubber damping element is symmetrically installed between the outer frame and the inner box by bolts.

[0010] Preferably, the inertial hysteresis damping device is connected to the cable clamp via a rotating shaft and is ultimately connected to the cable; the rotating shaft can rotate 360 ​​degrees, which can be adapted to any installation angle of the auxiliary cable.

[0011] Preferably, the cable clamp is bolted to the cable.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] The inertial-capacitive hysteretic damping auxiliary cable of this invention employs a shear-type high-damping rubber damper connected in parallel with an inertial container. The high-damping rubber damper features high stiffness and the absence of liquid substances, making it easily integrated with the auxiliary cable. The inertial container amplifies displacement, effectively increasing the additional damping provided by the damper. This inertial-capacitive hysteretic damping auxiliary cable vibration reduction measure is expected to better control the wide-frequency multi-mode vibration of ultra-long cable-stayed cables. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an inertial-capacitive hysteresis damping auxiliary cable;

[0015] Figure 2 This is a top view schematic diagram of an inertial-capacitive hysteresis-damped auxiliary cable;

[0016] Figure 3 for Figure 2 Diagram of direction A in the middle;

[0017] Figure 4 for Figure 2 Diagram of direction B in the middle;

[0018] Figure 5 This is a type of inertial-capacitive hysteresis damping auxiliary cable-stayed bridge layout;

[0019] Figure 6 This is a model of a single-cable-double-inertial-hysteresis-damped auxiliary cable system;

[0020] Figure 7 The results are for the example calculation.

[0021] In the diagram: 1-1, outer frame; 1-2, rubber damping element; 1-3, inner box; 1-4, lead screw; 1-5, rotating mass block; 1-6, ball bearing; 1-7, connecting clamp; 2, auxiliary cable; 3, rotating shaft; 4, cable clamp; 5, cable. Detailed Implementation

[0022] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0023] like Figures 1 to 5 As shown, an inertial-capacitive hysteresis damping auxiliary cable of the present invention includes an inertial-capacitive hysteresis damping device, an auxiliary cable, and a connecting cable clamp. The inertial-capacitive hysteresis damping device consists of an outer frame 1-1, a rubber damping element 1-2, an inner box 1-3, a lead screw 1-4, a rotating mass block 1-5, a ball bearing 1-6, and a connecting clamp 1-7; the auxiliary cable is made of steel strand 2; the inertial-capacitive hysteresis damping device is connected to the cable clamp 4 via a rotating shaft 3, and is finally connected to the tension cable 5.

[0024] Two rubber damping elements 1-2 are symmetrically installed between the outer frame 1-1 and the inner box 1-3 by bolts; the lead screw 1-4 is fixed to the bottom of the outer frame 1-1 and passes through the interior of the inner box 1-3; the rotating mass 1-5 passes through the lead screw 1-4 and is connected to the inner box 1-3 on both sides by ball bearings 1-6. When the lead screw 1-4 moves up and down, the rotating mass 1-5 can rotate; connecting clips 1-7 are provided on both sides of the outer frame 1-1, and the connecting clips 1-7 are used to fix the connecting steel strand 2.

[0025] The inertial hysteresis damping device is connected to the cable clamp 4 via a rotating shaft 3. The rotating shaft can rotate 360 ​​degrees, which can accommodate any installation angle of the auxiliary cable.

[0026] Explanation of the vibration reduction effect of the present invention:

[0027] To verify the effectiveness of the proposed cable-stayed inertial hysteresis damping auxiliary cable vibration reduction device, an analysis was conducted based on a single-cable-stayed cable-double-auxiliary-cable system model, as shown in the figure. Figure 6 As shown. The cable is placed horizontally with a chord length of L, a horizontal tension of H, and a mass per unit length of m. Parameters of auxiliary cable 1: hysteretic damping stiffness K1, hysteretic damping loss factor. Inertial container inertial mass parameter b1, auxiliary cable stiffness k1. Auxiliary cable 2 parameters: hysteresis damping stiffness K2, hysteresis damping loss factor. The inertial container's inertial mass parameter is b2, and the auxiliary cable stiffness is k2. The distance from auxiliary cable 1 to the left end of the cable is l1, and the distance from auxiliary cable 2 to the right end of the cable is l3. l2 = L - l1 - l3.

[0028] A complex modal analysis method was used to establish a model of a single-cable-stayed cable-double-auxiliary-cable system. The complex characteristic frequency equation of the system is as follows:

[0029]

[0030] in,

[0031]

[0032] Dimensionless parameters

[0033]

[0034] By solving the complex frequency equation (1) using numerical methods, the complex frequency ω of the nth mode of the system can be obtained. n and the corresponding complex wave number β n Furthermore, the cable modal damping ratio ζ can be obtained from formula (2). n

[0035]

[0036] Figure 7 Some analysis results are presented, namely the relationship curves between the system's first eight modal frequencies and damping ratio and hysteretic damping stiffness. Specific parameter settings for the auxiliary cables are shown in [link to analysis]. Figure 7 The frequency curves show that the modal frequencies of the system always increase with the increase of hysteretic damping stiffness, while there exists an optimal stiffness value for the damping ratio of each modality. When a hysteretic damping auxiliary cable (without inertial capacitance) is installed on the stay cable, the modal damping of the system can be significantly improved. It was also found that there are modes with relatively low modal damping and undamped modes. When an inertial capacitance device is added to the hysteretic damping auxiliary cable, the change in system modal frequency is smaller, and the modal damping ratio is significantly improved. The system has a margin of safety in multi-modal damping, allowing for further increases in hysteretic damping stiffness to further enhance the system frequency while ensuring damping requirements are met. Undamped modes also exist. Installing a single auxiliary cable is similar to damping measures, but there is a "vibration control blind spot". That is, when the auxiliary cable is installed at l1 / L=0.2, it is exactly located at the stagnation point of the fifth mode, resulting in zero damping ratio of that mode. When the auxiliary cable is distributed at two points of the stay cable, the system frequency, especially the fundamental frequency, can be further improved, while also taking into account the improvement of damping of all modes.

[0037] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. An inertial-capacitive hysteretic damping auxiliary cable, characterized in that: The device includes an inertial-capacitive hysteresis damping device, an auxiliary cable, and connecting cable clamps. A shear-type high-damping rubber damper is installed at the junction of the auxiliary cable and the main cable, connected in a parallel inertial container device. The inertial-capacitive hysteresis damping device includes an outer frame, an inner box, rubber damping elements, a ball screw, a rotating mass, and connecting clamps. The rubber damping elements are symmetrically installed between the outer frame and the inner box. The ball screw is fixed to the bottom of the outer frame and passes through the interior of the inner box. The rotating mass passes through the screw and is connected to the inner box via balls on both sides. Connecting clamps are provided on both sides of the outer frame to fix and connect the auxiliary cable. The inertial-capacitive hysteresis damping device is connected to the cable clamps via a rotating shaft and ultimately connected to the main cable.

2. The inertial-capacitive hysteresis damping auxiliary cable as described in claim 1, characterized in that: The auxiliary cable is made of steel strand.

3. The inertial-capacitive hysteretic damping auxiliary cable as described in claim 1, characterized in that: The rubber damping element is symmetrically installed between the outer frame and the inner box by bolts.

4. The inertial-capacitive hysteretic damping auxiliary cable as described in claim 1, characterized in that: The cable clamp is bolted to the cable.

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