A ladder-suspended magnetorheological vibration absorber structure and a single-tube tower vibration reduction method

Abstract

The present invention relates to a ladder-suspended magnetorheological vibration absorber structure and a single-tube tower vibration reduction method. The substructure comprises a ladder, a shape memory alloy spring, and a magnetorheological capacitive damper disposed within a tower. The ladder is provided with an internal magnetic element, and the tower's inner wall is provided with an internal magnetic element, magnetically attaching the ladder to one side of the tower's inner wall. The shape memory alloy spring is connected to the tower's top and the ladder, and the magnetorheological capacitive damper is connected to the ladder and the tower's bottom via a cable. During normal use, the ladder is attached to the tower's edge, with the shape memory alloy spring and cable taut. During abnormal vibration, the shape memory alloy spring pulls the detached ladder back to the tower's center, where the shape memory alloy spring and magnetorheological capacitive damper absorb and dissipate vibration energy. Compared to existing technologies, this invention eliminates the need for additional mass blocks, achieving efficient adaptive tuning vibration absorption and energy dissipation.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering and relates to a ladder-suspended magnetorheological vibration absorber structure and a single-tube tower vibration reduction method. Background Art

[0002] In the supplementary vibration subsystem used for vibration reduction on communication towers, the masses are primarily located at the tower top. However, due to their high height, communication towers primarily experience bending deformation under external excitations such as wind and seismic loads. When the masses are placed at the tower top, the relative deformation between the supplementary vibration subsystem and the tower body is small, limiting the energy absorption and vibration reduction capabilities. Further exploration is needed to design supplementary vibration subsystem layouts that can fully utilize the large differential deformation between the tower top and bottom under bending to improve the efficiency of tuned vibration absorption. Furthermore, the masses in supplementary vibration subsystems are typically additional, serving a single purpose, and exhibiting poor economic efficiency.

[0003] Most supplementary vibration subsystems used for vibration reduction on communication towers employ passive control, which has a narrow applicable frequency band and high frequency sensitivity. This makes traditional tuned mass dampers (TMDs) difficult to adapt to the tuning and vibration reduction requirements of communication towers. Further exploration is needed to apply semi-active or active control technologies to communication tower vibration reduction systems to improve their intelligence and efficiency.

[0004] Patent CN117847126A discloses a multi-directional vibration reduction eddy current damping device installed on a wind turbine, including a tower wall and a rotating platform. A deck is provided inside the tower wall. The bottom of the rotating platform is fixed on the deck and connected to a microcontroller. The other end of the microcontroller is connected to a displacement sensor. A horizontal eddy current damper is fixed to the upper part of the rotating platform. A permanent magnet is fixed to the bottom of the mass block, and buffer springs are provided at both ends of the mass block. The other end of the spring is connected to the base to achieve fixed frequency tuning and limiting effects to prevent the tuning displacement amplitude of the mass block from exceeding the limit. When the patented eddy current damper is subjected to external excitation, the permanent magnet at the bottom of the mass block moves along the connecting rod direction, thereby generating a changing magnetic field; in this process, the copper and iron sheets cut the magnetic lines of force, thereby generating a damping force; however, since the device uses permanent magnets, the internal magnetic field strength remains basically stable; therefore, the magnitude of the damping force mainly depends on the movement speed of the permanent magnet relative to the base; in the case of low-frequency vibration of the structure, the relative movement speed of the permanent magnet is slow, resulting in a small eddy current intensity, which cannot provide effective damping force; the additional cost of the additional mass and the installation space limitation also further limit the vibration control effect of the device in the full frequency domain.

[0005] Patent CN118746038A discloses a flexible pulley inertia damping vibration reduction device, comprising a first connecting plate, a second connecting plate, multiple pulley blocks, a one-way inertial mass damper, and a cable. The first connecting plate is connected to the top of the tower or the tail of the blade; the second connecting plate is connected to the bottom of the tower or the root of the blade; multiple pulley blocks are connected between the first connecting plate and the second connecting plate, wherein the pulley blocks are connected to the second connecting plate via a ball joint support; one end of the one-way inertial mass damper is connected to the side of the second connecting plate facing the first connecting plate via a ball joint support; one end of the cable is connected to the second connecting plate, and the other end is sequentially passed through multiple pulley blocks and connected to the one-way inertial mass damper. Although the one-way inertial mass damper of this patent achieves one-way transmission through a ratchet mechanism, during reverse motion, due to the torque at the fixed position, cumulative errors may occur, causing the position of the flywheel to shift, affecting the vibration reduction effect.

[0006] Patent CN113513557A discloses a magnetorheological damper and a method for controlling the loading force under wind-load vibration. The magnetorheological damper includes a piston rod, a cylinder, a positioning disk, a guide disk, a winding disk, an excitation coil and a spring; the cylinder is coaxially sleeved on the outer periphery of the middle portion of the piston rod, and the front and rear ends of the cylinder are sealed and slidably connected to the piston rod through a flange; the guide disk and the winding disk are tightly staggered along the axial direction on the piston rod in the cylinder, and a magnetorheological fluid channel is formed between the inner circumference of the guide disk and the winding disk and the piston rod, and the magnetorheological cavity is filled with magnetorheological fluid; an excitation coil is wound on each winding disk, and the excitation coils on all winding disks are connected in series; the positioning disk is coaxially sleeved on the piston rod located outside the front flange; the spring is sleeved on the outer periphery of the cylinder, one end of the spring is mounted on the positioning disk, and the other end of the spring is mounted on the flange located at the rear end; one end of the positioning disk is connected to the roller O a or O b , the piston rod on the side away from the positioning plate is connected to the roller O b or O a However, in the patented magnetorheological damper, the design of the guide disk and winding disk needs to balance the magnetic induction intensity and structural strength. If the guide disk is too thick, the magnetic induction intensity may reach saturation prematurely, resulting in the magnetorheological damper output damping force failing to reach the required maximum damping force. If the guide disk is too thin, it may weaken the structural strength and affect the overall performance of the device. Summary of the Invention

[0007] The purpose of the present invention is to provide a ladder-suspended magnetorheological absorber structure and a single-tube tower vibration reduction method in order to overcome at least one of the defects of the above-mentioned prior art. The present invention does not require additional mass blocks to achieve efficient adaptive tuning vibration absorption and energy consumption.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] One of the technical solutions of the present invention is to provide a ladder-suspended magnetorheological oscillator structure. The structure includes a ladder, a shape memory alloy (SMA) spring, and a magnetorheological capacitive damper disposed within a tower body. A ladder internal magnetic attraction member is disposed within the ladder, and a tower internal magnetic attraction member is disposed on the inner wall of the tower body. The ladder is magnetically attracted to one side of the inner wall of the tower body. The ladder is designed as a solid mass block. The ladder, shape memory alloy spring, and magnetorheological capacitive damper together constitute a tuned mass damper (TMD) system.

[0010] The shape memory alloy spring is connected to the tower top and the ladder, and the shape memory alloy spring causes the ladder to generate corresponding displacement when the tower body vibrates, thereby absorbing vibration energy;

[0011] The magnetorheological inertial damper is connected to the ladder and the tower base via a cable. The magnetorheological inertial damper provides amplified additional inertial mass to effectively absorb and dissipate vibration energy between the ladder mass block and the tower body, and adjusts the vibration absorption frequency of the ladder suspension.

[0012] During normal use, the ladder is adsorbed on the edge of the tower body, and the shape memory alloy spring and the cable are tightened. During abnormal vibration, the shape memory alloy spring pulls the detached ladder back to the center of the tower body, and the shape memory alloy spring and magnetorheological inertia damper absorb and dissipate vibration energy and realize the self-reset function.

[0013] As a preferred technical solution, at least one pair of lifting rings is respectively provided on both sides of the top and bottom of the tower body, at least two pairs of lifting rings are provided on the ladder, the two ends of at least one pair of shape memory alloy springs are respectively connected to the lifting rings of the tower top and the ladder, and the two ends of at least one pair of magnetorheological inertia dampers are respectively connected to the lifting rings of the ladder and the bottom of the tower body through cables.

[0014] Furthermore, the material of the shape memory alloy spring is selected from one or more of nickel-titanium shape memory alloy (Ni-Ti SMA), copper-based shape memory alloy (Cu SMA), and iron-based shape memory alloy (Fe SMA). The shape memory alloy spring has a unique shape memory effect and superelastic properties, and is connected to the ladder and the tower body to ensure that the ladder can generate corresponding reverse movement when the structure vibrates.

[0015] As a preferred technical solution, the natural frequency of the tuned mass damper system is adjusted by adjusting the stiffness of the shape memory alloy spring.

[0016] Furthermore, magnetic components are provided in the hollow vertical rods on both sides of the ladder, and magnetic components are provided on the inner wall of the tower body at positions opposite to the magnetic components in the ladder. The magnetic components in the ladder and the magnetic components in the tower form a magnetic connection assembly, and the magnetic components in the tower attract the magnetic components in the ladder, thereby connecting the ladder to the tower body in a non-rigid manner.

[0017] The magnetic attraction parts inside the ladder and the magnetic attraction parts inside the tower are made of a combination of electromagnets and magnetic materials. The adsorption of the magnetic material is achieved by controlling the power supply of the electromagnet. Under normal use, the magnetic connection component is in a powered state, and there is an attractive force between the electromagnet and the magnetic material, which can firmly adsorb the ladder to the tower body. When the disconnect signal from the control unit is received, the power is cut off and the ladder is detached from the tower body, thereby obtaining shaking space during the vibration process.

[0018] As a preferred technical solution, the magnetorheological inertial damper, the magnetic attraction parts in the ladder and the magnetic attraction parts in the tower are connected to a circuit assembly, which includes cables, hooks, and a wiring ring device. Cables are laid in the tower body, and hooks are provided on the inner wall of the tower body, the ladder and the cable. The hooks are provided with a wiring ring device, and a number of cable clamping sleeves are arranged on the wiring ring device. During the wiring process, the cables in the tower body are pressed into the groove of each cable clamping sleeve to ensure that the cables are tightly and parallelly attached to the inner wall of the tower body, thereby achieving an efficient and stable wiring layout.

[0019] As an optimal technical solution, the cable is connected to the excitation coil in the magnetorheological inertial damper, the magnetic parts in the ladder and the magnetic parts in the tower, and is connected to the power regulation and supply equipment to adjust the current according to the signal of the control unit.

[0020] Furthermore, the magnetorheological inertia damper includes an inner sleeve and an outer sleeve, the inner sleeve extends into the outer sleeve, the exposed end of the inner sleeve and the end opposite to the outer sleeve are respectively connected to the cable, and an outer piston is provided on the end of the inner sleeve that extends. When the ladder vibrates, the cable will pull the inner sleeve. At this time, the inner sleeve is equivalent to a guide rod, which in turn pulls the outer piston to move. A screw nut is fixedly provided in the inner sleeve of the outer piston, and the outer piston is sleeved on the ball screw through the screw nut. The smooth end of the ball screw is rotatably arranged in the outer sleeve through a bearing, and the screw nut drives the ball screw to rotate. A flywheel is sleeved on the ball screw in the inner sleeve, and limit plates are provided on both sides of the flywheel in the inner sleeve, so that the flywheel is limited by the limit plates. When blocked, it can be driven by the ball screw to rotate around the ball screw. The ball screw system converts the axial translational acceleration into rotational acceleration, and the flywheel further converts the translational kinetic energy into rotational kinetic energy. Due to the existence of the flywheel's rotational inertia, an inertial force will be generated. The essence of the inertia coefficient is the translational equivalent of the rotational inertia force. Since the inertial effect generated by the flywheel's rotational inertia is much greater than the inertial effect of the flywheel's physical mass, the magnetorheological inertia damper can use a smaller physical mass to generate a larger apparent mass and its enhanced inertial force, thereby achieving the effect of inertia enhancement. That is, at this time, the inertia coefficient of the flywheel is much greater than the actual physical mass of the flywheel. The amplified additional inertial mass can adjust the suspension vibration absorption frequency of the ladder to improve the vibration reduction performance of the traditional tuned mass damper.

[0021] As a preferred technical solution, by adjusting the actual physical mass of the flywheel, a certain inertia coefficient that meets the structural control requirements can be generated.

[0022] Furthermore, thrust ball bearings are provided on both sides of the flywheel, and the thrust ball bearings are sleeved on the ball screw. The bearing tight ring of the thrust ball bearing is connected to the flywheel, and the bearing loose ring is connected to the limit plate.

[0023] Furthermore, the two threaded sections of the ball screw with opposite thread directions are respectively sleeved with at least one pair of flywheels, and the two flywheels can rotate in opposite directions by changing the thread direction of the ball screw to reduce torque.

[0024] Furthermore, an inner piston is provided on the part into which the inner sleeve extends, and the inner piston also moves under the pull of the inner sleeve. The cavity between the inner sleeve and the outer sleeve is filled with magnetorheological fluid, and an excitation coil is provided in the outer sleeve at a position relative to the inner piston. Under the squeezing of the inner piston, the magnetorheological fluid will pass through the damping channel between the inner piston and the excitation coil, thereby generating a certain amount of damping force.

[0025] The magnetorheological fluid has special rheological properties. Under zero magnetic field, the particles of the magnetorheological fluid are distributed randomly and irregularly. However, under the action of a magnetic field, the particles are arranged in a chain-like shape along the direction of the magnetic field, causing the magnetorheological fluid to transform from its original fluid state to a solid-like state. During this process, the magnetorheological fluid generates a shear yield strength, which increases with the increase of magnetic field intensity. The damping generated by the magnetorheological fluid when flowing through the damping channel also increases, thereby correspondingly increasing the output damping force of the magnetorheological inertia damper. The rheological process of the magnetorheological fluid can be achieved in an extremely short time, and this transformation is reversible.

[0026] As an optimal technical solution, the viscosity of the magnetorheological fluid is changed by adjusting the access current of the excitation coil in real time, and then the damping force of the magnetorheological inertial damper is adjusted in real time, thereby achieving vibration control and energy dissipation in a wider frequency range.

[0027] As a preferred technical solution, the magnetorheological fluid provides an inertia effect by changing the size of the cavity between the inner sleeve and the outer sleeve. Different cavity sizes achieve different magnetorheological fluid masses to achieve different inertia coefficients.

[0028] As a preferred technical solution, the sensor acquires the response signal of the structure, and the main processor performs semi-active control operations based on the acquired signal to output a control voltage signal. The programmable current source outputs an excitation current based on the voltage signal to change the magnetic field. The magnetorheological fluid changes its rheological properties under the action of the external magnetic field, that is, under the action of the magnetic field, the flow properties of the magnetorheological fluid change, thereby changing the damping coefficient and liquid inertia coefficient of the magnetorheological inertial damper. The magnetorheological inertial damper has the advantages of fast response speed and continuously adjustable damping force, which enables it to quickly adapt to the tracking of the optimal control force and realize semi-active control.

[0029] Furthermore, a spiral pipe is axially opened on the outer wall of the cavity between the inner sleeve and the outer sleeve in the outer sleeve, and the magnetorheological fluid circulates in the cavity and the spiral pipe. In this process, the original translational motion caused by the force on the inner piston and the outer piston is converted into rotation of the magnetorheological fluid around the spiral pipe. Although the fluid flow rate of the magnetorheological fluid in the spiral pipe and the cavity is the same, the difference in the contact area between the piston and the magnetorheological fluid in the cavity and the cross-sectional area of ​​the spiral pipe causes the flow velocity of the magnetorheological fluid to change. The flow velocity of the magnetorheological fluid in the spiral pipe is much greater than the flow velocity in the cavity. The inertia amplification effect in this process also causes the magnetorheological inertia damper to generate a larger inertial force.

[0030] Furthermore, pads are provided between the contact surfaces of the top and bottom of the ladder and the tower body, which can reduce the friction effect when the ladder shakes;

[0031] The material of the pad is selected from one or more of polytetrafluoroethylene, ultra-high molecular weight polyethylene, and polyurethane. The pads of these materials have low friction characteristics. Arranging low-friction plates on the contact surface can reduce the friction force generated by the contact surface in the opposite direction of relative movement when the ladder shakes, so that the ladder can shake relative to the single-tube tower during vibration and will not stop or shake too little due to the resistance at the contact surface.

[0032] One of the technical solutions of the present invention is to provide a single-tube tower vibration reduction method, which uses the substructure to reduce the vibration of the single-tube tower, and the method includes the following steps:

[0033] Under normal use, the electromagnet is energized, and there is magnetic attraction between the magnetic parts inside the ladder and the magnetic parts inside the tower. The ladder is firmly adsorbed to one side of the inner wall of the single-tube tower, and the shape memory alloy springs and cables on both sides of the ladder are in a taut state.

[0034] When the sensor detects abnormal vibration, the control unit outputs a signal to adjust the current, causing the electromagnet to be de-energized, the ladder to detach, and under the tension of the shape memory alloy spring, it returns from the edge of the single-tube tower to the center.

[0035] When the main structure of the single-tube tower vibrates, the ladder, under the action of the shape memory alloy spring, moves in the opposite direction of the structural vibration, generating an inertial force in the opposite direction of the vibration of the single-tube tower. When the structure vibrates under the action of external excitation, since the single-tube tower is connected to the ladder via the shape memory alloy spring, the ladder vibrates with the single-tube tower and reacts the inertial force generated by the relative movement to the main structure of the single-tube tower. By tuning this inertial force, it can effectively offset some structural vibrations, so that the vibration response of the main structure is attenuated and controlled.

[0036] When the main structure of the single-tube tower vibrates, the inner sleeve drives the ball screw and flywheel to rotate, converting translational kinetic energy into rotational kinetic energy. The inertia component composed of the ball screw and flywheel has a mass amplification effect, which can achieve a larger apparent mass with a smaller mass to absorb and dissipate the vibration energy of the ladder. The larger the inertia coefficient, the stronger the magnetorheological inertia damper's ability to absorb and dissipate energy. At the same time, the magnetorheological inertia damper works in conjunction with the series cable to locally amplify the relative deformation of the magnetorheological damping unit, thereby effectively reducing the relative displacement of the ladder with respect to the single-tube tower.

[0037] Driven by the inner sleeve, the inner and outer pistons move linearly, forcing the magnetorheological fluid to flow along the spiral pipe into the cavity between the inner and outer sleeves, forming a circulation flow of the magnetorheological fluid in the cavity and the spiral pipe. The inertial amplification effect caused by the difference in flow velocity between the magnetorheological fluid in the spiral pipe and the cavity also causes the magnetorheological inertial damper to generate a large inertial force, further consuming the vibration energy of the ladder.

[0038] When the magnetorheological fluid passes through the gap between the inner piston and the excitation coil, it produces shear and extrusion effects, thereby generating a damping force, which consumes the relative motion energy between the ladder and the single-tube tower, gradually stabilizing the tuned mass damper system and reducing the vibration amplitude and duration of the structure, thereby achieving semi-active efficiency enhancement and multi-objective vibration absorption and reduction of the single-tube tower under random external excitations such as wind loads and earthquakes.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The present invention innovatively utilizes a ladder to absorb vibration energy. The ladder inside the single-tube tower is designed as a movable mass block, so that the ladder has dual structural and vibration reduction functions. Under normal use, it is fixed to the inner wall of the single-tube tower by magnetic attraction, and serves as a passage for workers to install, maintain, and repair the single-tube tower structure and upper equipment. When abnormal vibration of the main structure of the single-tube tower is detected, the ladder is detached and forms a tuned mass damper system with the shape memory alloy spring and the magnetorheological inertia damper, directly participating in the vibration reduction process. The internal space of the single-tube tower is used for tuned vibration absorption, and no additional tuned vibration absorption mass is added, which effectively reduces the complexity and cost of the system.

[0041] (2) The present invention directly uses the ladder as the mass block in the tuned mass damper system, which is equivalent to arranging the mass block throughout the height. The single-tube tower is mainly composed of a large-diameter tapered steel tube and is a self-supporting tall steel structure. Under the action of wind load and seismic load, the internal force is mainly controlled by the bending moment, and the main bending deformation occurs. After deformation, the vertical cross-section unit presents a trapezoidal or quasi-trapezoidal shape, and the inter-layer deformation is small. The layout of the present invention can fully utilize the large deformation difference between the top and bottom of the single-tube tower under bending deformation, thereby improving the tuning vibration absorption capacity and efficiency;

[0042] (3) The present invention uses a magnetorheological capacitive damper to provide damping force for the tuned mass damper system. In the tuned mass damper system, the ladder absorbs part of the vibration energy through interaction with the single-tube tower body, and the magnetorheological capacitive damper then dissipates the energy.

[0043] (4) Shape memory alloy springs have shape memory effect and superelastic effect. Their recoverable strain is as high as 6-8%, which is much higher than that of traditional building materials. After the external force is unloaded, the shape of the alloy will be completely restored, with basically no residual deformation, and it has a certain hysteresis energy dissipation capacity. The magnetorheological damping part designed based on the rheological characteristics of magnetorheological fluid can control the output damping force in real time by changing the loading current. The inertia part can provide an amplified equivalent apparent inertial mass to achieve efficient vibration energy absorption. The inertia part works together with the magnetorheological damping part to achieve semi-active magnetorheological inertia. The deformation of the damper is amplified; however, since the top installation space of the tuned mass damper is limited when it is used as a single-tube tower vibration reduction structure, it is difficult to synergistically give play to the advantages of the above-mentioned technologies; in view of this, the ladder-suspended magnetorheological vibration absorber structure proposed in the present invention can make full use of the self-resetting performance of the shape memory alloy spring and the adjustable characteristics of the damping force and inertia coefficient of the magnetorheological inertia damper, combined with the real-time sensing data of the single-tube tower, to build a semi-active vibration reduction control substructure and adaptive control suitable for the single-tube tower structure, which is conducive to further realizing the tuning energy consumption efficiency improvement of the single-tube tower vibration reduction system. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the cross-sectional structure of the ladder-suspended magnetorheological absorber structure in an embodiment of the present invention;

[0045] Figure 2 Schematic diagram of the top view of the ladder-suspended magnetorheological absorber structure in an embodiment of the present invention;

[0046] Figure 3 This is a schematic cross-sectional view of a ladder according to an embodiment of the present invention;

[0047] Figure 4 Schematic diagram of the cross-sectional structure of the magnetorheological inertia damper in an embodiment of the present invention.

[0048] Description of the marks in the figure:

[0049] 1—ladder, 2—shape memory alloy spring, 3—magnetorheological inertia damper, 4—shim, 5—magnetic component in ladder, 6—magnetic component in tower, 7—inner sleeve, 8—outer sleeve, 9—cable, 10—flywheel, 11—ball screw, 12—screw nut, 13—thrust ball bearing, 14—inner piston, 15—outer piston, 16—magnetorheological fluid, 17—excitation coil, 18—spiral pipe. DETAILED DESCRIPTION

[0050] The present invention is described in detail below with reference to specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0051] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like, used to describe common objects, merely refer to different instances of the same object and are not intended to imply that the objects described must be in a given order, whether temporally, spatially, sequentially, or in any other manner.

[0052] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0053] Example:

[0054] A ladder-suspended magnetorheological oscillator structure, such as Figure 1 and Figure 2 As shown, it includes a ladder 1, a shape memory alloy (SMA) spring 2, and a magnetorheological inertial damper 3 disposed in a tower body. An internal ladder magnetic attraction member 5 is disposed in the ladder 1, and an internal tower magnetic attraction member 6 is disposed on the inner wall of the tower body. The ladder 1 is adsorbed to one side of the inner wall of the tower body by magnetic attraction. The ladder 1 is designed as a whole and serves as a solid mass block. The ladder 1, the shape memory alloy spring 2, and the magnetorheological inertial damper 3 together constitute a tuned mass damper (TMD) system.

[0055] The shape memory alloy spring 2 is connected to the tower top and the ladder 1. The shape memory alloy spring 2 causes the ladder 1 to produce corresponding displacement when the tower body vibrates, thereby absorbing vibration energy.

[0056] The shape memory alloy spring 2 is made of one or more of a nickel-titanium-based shape memory alloy (Ni-Ti SMA, such as nickel-titanium-copper (Ni-Ti-Cu)), a copper-based shape memory alloy (Cu SMA, such as copper-zinc-aluminum (Cu-Zn-Al)), and an iron-based shape memory alloy (FeSMA, such as iron-manganese-silicon (Fe-Mn-Si)). In this embodiment, nickel-titanium-copper is preferred. The shape memory alloy spring 2 has a unique shape memory effect and superelastic properties. It is connected to the ladder 1 and the tower body to ensure that the ladder 1 can generate corresponding reverse movement when the structure vibrates.

[0057] By adjusting the stiffness of the shape memory alloy spring 2, the natural frequency of the tuned mass damper system is adjusted;

[0058] The magnetorheological inertial damper 3 is connected to the ladder 1 and the tower base via a cable 9. The magnetorheological inertial damper 3 provides amplified additional inertial mass to effectively absorb and dissipate vibration energy between the ladder 1 mass block and the tower body, and adjusts the suspension vibration absorption frequency of the ladder 1.

[0059] At least one pair of lifting rings is welded on both sides of the top and bottom of the tower body. In this embodiment, it is preferably a pair of two at the top of the tower body and a pair of two at the bottom of the tower body. At least two pairs of lifting rings are welded on the middle section of the ladder 1. In this embodiment, it is preferably two pairs of four. The two ends of at least one pair of shape memory alloy springs 2 are respectively connected to the lifting rings at the top of the tower body and the middle section of the ladder 1. In this embodiment, it is preferably a pair of two shape memory alloy springs 2. The two ends of at least one pair of magnetorheological inertia dampers 3 are respectively connected to the lifting rings at the middle section of the ladder 1 and the bottom of the tower body through cables 9. In this embodiment, it is preferably a pair of two magnetorheological inertia dampers 3.

[0060] During normal use, the ladder 1 is adsorbed on the edge of the tower body, and the shape memory alloy spring 2 and the cable 9 are tightened. In the event of abnormal vibration, the shape memory alloy spring 2 pulls the detached ladder 1 back to the center of the tower body. The shape memory alloy spring 2 and the magnetorheological inertia damper 3 absorb and dissipate the vibration energy and realize the self-reset function.

[0061] Pads 4 are provided between the contact surfaces of the top and bottom of the ladder 1 and the tower body, and the pads 4 can reduce the friction effect when the ladder 1 shakes;

[0062] The material of the pad 4 is selected from one or more of polytetrafluoroethylene, ultra-high molecular weight polyethylene, and polyurethane. In this embodiment, polytetrafluoroethylene is preferably used. The pad 4 of these materials has low friction properties. Arranging a low-friction plate on the contact surface can reduce the friction force generated on the contact surface in the opposite direction of relative motion when the ladder 1 shakes, so that the ladder 1 can shake relative to the single-tube tower during vibration without being stationary or shaking too little due to resistance at the contact surface.

[0063] like Figure 3 As shown, the ladder 1 is provided with internal magnetic parts 5 in the hollow uprights on both sides, and the tower body is provided with internal magnetic parts 6 on the inner wall of the tower body at a position opposite to the internal magnetic parts 5. The internal magnetic parts 5 and the internal magnetic parts 6 form a magnetic connection assembly. The internal magnetic parts 6 attract the internal magnetic parts 5 to connect the ladder 1 to the tower body in a non-rigid manner.

[0064] The magnetic attraction member 5 in the ladder and the magnetic attraction member 6 in the tower are a combination of an electromagnet and a magnetic material. In this embodiment, the magnetic attraction member 5 in the ladder is an electromagnet, and the magnetic attraction member 6 in the tower can be made of steel. By controlling the power supply of the electromagnet, the magnetic material is adsorbed. Under normal use, the magnetic connection assembly is in a powered state, and there is an attractive force between the electromagnet and the magnetic material, which can firmly adsorb the ladder 1 on the tower body. When a disconnect signal is received from the control unit, the power is cut off and the ladder 1 is detached from the tower body, thereby obtaining a shaking space during the vibration process.

[0065] The magnetorheological inertia damper 3, the magnetic attraction member 5 in the ladder, and the magnetic attraction member 6 in the tower are connected to the circuit assembly. The circuit assembly includes cables, hooks, and a wiring ring device. Cables are arranged in the tower body. Hooks are provided on the inner wall of the tower body, the ladder 1, and the cable 9. The hooks are provided with a wiring ring device. The wiring ring device is provided with several cable clamping sleeves. During the wiring process, the cables in the tower body are pressed into the grooves of each cable clamping sleeve to ensure that the cables are tightly and parallelly attached to the inner wall of the tower body, thereby achieving an efficient and stable wiring layout;

[0066] The cable is connected to the excitation coil 17 in the magnetorheological inertial damper 3, the magnetic attraction component 5 in the ladder, and the magnetic attraction component 6 in the tower. It is also connected to the power supply and regulation equipment such as the transformer and distribution cabinet of the communication base station, and the current is adjusted according to the signal of the control unit.

[0067] like Figure 4As shown, the magnetorheological inertia damper 3 includes an inner sleeve 7 and an outer sleeve 8. The inner sleeve 7 extends into the outer sleeve 8. The exposed end of the inner sleeve 7 and the end opposite to the outer sleeve 8 are respectively connected to the cable 9. An outer piston 15 is provided on the end of the inner sleeve 7. When the ladder 1 vibrates, the cable 9 will pull the inner sleeve 7. At this time, the inner sleeve 7 is equivalent to a guide rod, which in turn pulls the outer piston 15 to move. A screw nut 12 is fixedly provided in the inner sleeve 7 of the outer piston 15. The outer piston 15 is sleeved on the ball screw 11 through the screw nut 12. The smooth end of the ball screw 11 is rotatably arranged in the outer sleeve 8 through a bearing. The screw nut 12 drives the ball screw 11 to rotate. A flywheel 10 is sleeved on the ball screw 11 in the inner sleeve 7. Limit plates are provided on both sides of the flywheel 10 in the inner sleeve 7, so that the flywheel 10 is limited. When the position plate blocks it, it can be driven by the ball screw 11 to rotate around the ball screw 11, the ball screw system converts the axial translational acceleration into rotational acceleration, and the flywheel 10 further converts the translational kinetic energy into rotational kinetic energy. Due to the existence of the rotational inertia of the flywheel 10, an inertial force will be generated. The essence of the inertia coefficient is the translational equivalent of the rotational inertial force. Since the inertial effect generated by the rotational inertia of the flywheel 10 is much greater than the inertial effect of the physical mass of the flywheel 10, the magnetorheological inertia damper 3 can use a smaller physical mass to generate a larger apparent mass and its synergistic inertial force, thereby achieving the effect of inertia synergy, that is, at this time the inertia coefficient of the flywheel 10 is much greater than the actual physical mass of the flywheel 10. The amplified additional inertial mass can adjust the suspension vibration absorption frequency of the ladder 1 to improve the vibration reduction performance of the traditional tuned mass damper.

[0068] By adjusting the actual physical mass of the flywheel 10, a certain size of inertia coefficient that meets the structural control requirements can be generated;

[0069] Thrust ball bearings 13 are provided on both the upper and lower sides of the flywheel 10. The thrust ball bearings 13 are sleeved on the ball screw 11. The bearing tight ring of the thrust ball bearing 13 is connected to the flywheel 10, and the bearing loose ring is connected to the limit plate.

[0070] The upper and lower threaded sections of the ball screw 11 with opposite thread directions are respectively provided with at least one pair of flywheels 10. In this embodiment, preferably a pair is provided. By changing the thread direction of the ball screw 11, the two flywheels 10 rotate in opposite directions to reduce torque.

[0071] An inner piston 14 is provided on the central portion where the inner sleeve 7 extends. The inner piston 14 also moves under the pull of the inner sleeve 7. The cavity between the inner sleeve 7 and the outer sleeve 8 is filled with magnetorheological fluid 16. An excitation coil 17 is provided in the outer sleeve 8 at a position opposite to the inner piston 14. Under the pressure of the inner piston 14, the magnetorheological fluid 16 passes through the damping channel between the inner piston 14 and the excitation coil 17, thereby generating a certain amount of damping force.

[0072] The components of the magnetorheological fluid 16 include magnetic particles, a non-magnetic carrier fluid, and additives. The magnetic particles are selected from one or more of carbonyl iron powder, ferroferric oxide (Fe3O4) powder, and cobalt powder. The non-magnetic carrier fluid is selected from one or more of silicone oil, water, and mineral oil with different viscosity coefficients. The additives are selected from one or more of a dispersant, an anti-settling agent, a lubricant, and a thixotropic agent. The material of the magnetorheological fluid 16 is selected from one or more of Bohai A172 magnetorheological fluid, Bohai A181 magnetorheological fluid, and MRF15 magnetorheological fluid. In this embodiment, Bohai A172 magnetorheological fluid is preferred. The magnetorheological fluid 16 has unique rheological properties. Under zero magnetic field, the particles of the magnetorheological fluid 16 are distributed randomly and irregularly. However, under the action of a magnetic field, the particles are arranged in a chain-like manner along the magnetic field direction, causing the magnetorheological fluid 16 to transform from its original fluid state to a solid-like state. During this process, the magnetorheological fluid 16 develops a shear yield strength that increases with increasing magnetic field intensity. The damping generated by the magnetorheological fluid 16 when flowing through the damping channel also increases, thereby correspondingly increasing the output damping force of the magnetorheological inertia damper 3. The rheological process of the magnetorheological fluid 16 can be achieved in a very short time, and this transformation is reversible.

[0073] By adjusting the current of the excitation coil 17 in real time to change the viscosity of the magnetorheological fluid 16, and then adjusting the damping force of the magnetorheological inertia damper 3 in real time, vibration control and energy dissipation in a wide frequency range are achieved;

[0074] The magnetorheological fluid 16 provides an inertia effect by changing the size of the cavity between the inner sleeve 7 and the outer sleeve 8. Different cavity sizes achieve different masses of magnetorheological fluid 16 to achieve different inertia coefficients.

[0075] The sensor collects the response signal of the structure, and the main processor performs semi-active control operations based on the collected signal, outputting a control voltage signal. The programmable current source outputs an excitation current based on the voltage signal, thereby changing the magnetic field. The magnetorheological fluid 16 changes its rheological properties under the action of the external magnetic field. That is, under the action of the magnetic field, the flow properties of the magnetorheological fluid 16 change, thereby changing the damping coefficient and liquid inertia coefficient of the magnetorheological inertia damper 3. The magnetorheological inertia damper 3 has the advantages of fast response speed and continuously adjustable damping force, which enables it to quickly adapt to the tracking of the optimal control force and realize semi-active control.

[0076] A spiral pipe 18 is axially provided on the outer wall of the cavity between the inner sleeve 7 and the outer sleeve 8 in the outer sleeve 8, and the magnetorheological fluid 16 circulates in the cavity and the spiral pipe 18. During this process, the original translational motion of the inner piston 14 and the outer piston 15 caused by the force is converted into the rotation of the magnetorheological fluid 16 around the spiral pipe 18. Although the fluid flow rate of the magnetorheological fluid 16 in the spiral pipe 18 and the cavity is the same, the difference in the contact area between the piston and the magnetorheological fluid 16 in the cavity and the cross-sectional area of ​​the spiral pipe 18 causes the flow velocity of the magnetorheological fluid 16 to change. The flow velocity of the magnetorheological fluid 16 in the spiral pipe 18 is much greater than the flow velocity in the cavity. The inertia amplification effect in this process also causes the magnetorheological inertia damper 3 to generate a larger inertial force.

[0077] A single-tube tower vibration reduction method uses the above-mentioned substructure to reduce the vibration of the single-tube tower, and the specific steps are as follows:

[0078] Under normal use, the electromagnet is energized, and there is a magnetic attraction between the magnetic attraction part 5 in the ladder and the magnetic attraction part 6 in the tower. The ladder 1 is firmly adsorbed on one side of the inner wall of the single-tube tower, and the shape memory alloy springs 2 and cables 9 on both sides of the ladder 1 are in a taut state.

[0079] When the sensor detects abnormal vibration, the control unit outputs a signal to adjust the current, so that the electromagnet is de-energized, the ladder 1 is detached, and under the tension of the shape memory alloy spring 2, it returns from the edge of the single-tube tower to the center.

[0080] When the main structure of the single-tube tower vibrates, the ladder 1 moves in the opposite direction of the structural vibration under the action of the shape memory alloy spring 2, generating an inertial force in the opposite direction of the vibration of the single-tube tower. When the structure vibrates under the action of external excitation, since the single-tube tower is connected to the ladder 1 via the shape memory alloy spring 2, the ladder 1 vibrates with the single-tube tower and reacts the inertial force generated by the relative movement to the main structure of the single-tube tower. By tuning this inertial force, it can effectively offset some structural vibrations, so that the vibration response of the main structure is attenuated and controlled;

[0081] When the main structure of the single-tube tower vibrates, the inner sleeve 7 drives the ball screw 11 and the flywheel 10 to rotate, converting the translational kinetic energy into rotational kinetic energy. The inertia portion formed by the ball screw 11 and the flywheel 10 has a mass amplification effect, which can achieve a larger apparent mass with a smaller mass to absorb and dissipate the vibration energy of the ladder 1. The larger the inertia coefficient, the stronger the ability of the magnetorheological inertia damper 3 to absorb and dissipate energy. At the same time, the magnetorheological inertia damper 3 works in conjunction with the series-connected cable 9 to locally amplify the relative deformation of the magnetorheological damping unit, thereby effectively reducing the relative displacement of the ladder 1 with respect to the single-tube tower.

[0082] Driven by the inner sleeve 7, the inner piston 14 and the outer piston 15 move linearly, forcing the magnetorheological fluid 16 to flow along the spiral pipe 18 into the cavity between the inner sleeve 7 and the outer sleeve 8, forming a circulation flow of the magnetorheological fluid 16 in the cavity and the spiral pipe 18. The inertial amplification effect caused by the difference in flow velocity of the magnetorheological fluid 16 in the spiral pipe 18 and in the cavity also causes the magnetorheological inertial damper 3 to generate a large inertial force, further consuming the vibration energy of the ladder 1;

[0083] When the magnetorheological fluid 16 passes through the gap between the inner piston 14 and the excitation coil 17, it produces shearing and squeezing effects, thereby generating a damping force, consuming the relative motion energy between the ladder 1 and the single-tube tower, making the tuned mass damper system gradually stabilize, reducing the vibration amplitude and duration of the structure, and realizing semi-active efficiency enhancement and multi-objective vibration absorption and reduction of the single-tube tower under random external excitations such as wind loads and earthquakes.

[0084] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. 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 scope of protection of the present invention.

Claims

1. A ladder-suspended magnetorheological oscillator structure, characterized in that: The substructure comprises a ladder (1), a shape memory alloy spring (2) and a magnetorheological inertial damper (3) arranged in a tower body, wherein a ladder internal magnetic attraction component (5) is arranged in the ladder (1), and a tower internal magnetic attraction component (6) is arranged on the inner wall of the tower body, and the ladder (1) is adsorbed to one side of the inner wall of the tower body by magnetic attraction, and the ladder (1) is designed as a whole and used as a solid mass block, and the ladder (1), the shape memory alloy spring (2) and the magnetorheological inertial damper (3) together constitute a tuned mass damper system; The shape memory alloy spring (2) is connected to the tower top and the ladder (1), and the magnetorheological inertia damper (3) is connected to the ladder (1) and the tower bottom via a cable (9); During normal use, the ladder (1) is adsorbed on the edge of the tower body, and the shape memory alloy spring (2) and the cable (9) are tightened. During abnormal vibration, the shape memory alloy spring (2) pulls the detached ladder (1) back to the center of the tower body, and the shape memory alloy spring (2) and the magnetorheological inertia damper (3) absorb and dissipate vibration energy. The magnetorheological inertia damper (3) includes an inner sleeve (7) and an outer sleeve (8), the inner sleeve (7) extends into the outer sleeve (8), the exposed end of the inner sleeve (7) and the end opposite to the outer sleeve (8) are respectively connected to the cable (9), an outer piston (15) is provided on the end of the inner sleeve (7) that extends into the outer sleeve, a screw nut (12) is fixedly provided in the inner sleeve (7) in the outer piston (15), the outer piston (15) is sleeved on the ball screw (11) through the screw nut (12), the ball screw (11) is rotatably provided in the outer sleeve (8), a flywheel (10) is sleeved on the ball screw (11) in the inner sleeve (7), and limit plates are provided on both sides of the flywheel (10) in the inner sleeve (7); An inner piston (14) is provided on the portion into which the inner sleeve (7) extends, a cavity between the inner sleeve (7) and the outer sleeve (8) is filled with magnetorheological fluid (16), an excitation coil (17) is provided in the outer sleeve (8) at a position relative to the inner piston (14), and the magnetorheological fluid (16) passes through a damping channel between the inner piston (14) and the excitation coil (17) under the pressure of the inner piston (14).

2. The ladder-suspended magnetorheological oscillator structure according to claim 1, characterized in that: The material of the shape memory alloy spring (2) is selected from one or more of nickel-titanium-based shape memory alloy, copper-based shape memory alloy, and iron-based shape memory alloy.

3. The ladder-suspended magnetorheological oscillator structure according to claim 1, characterized in that: The ladder (1) is provided with internal magnetic parts (5) in the hollow vertical rods on both sides, and internal magnetic parts (6) are provided on the inner wall of the tower body at a position opposite to the internal magnetic parts (5) of the ladder, and the ladder (1) is connected to the tower body by the internal magnetic parts (6) adsorbing the internal magnetic parts (5) of the ladder; The magnetic attraction component (5) in the ladder and the magnetic attraction component (6) in the tower are made of a combination of electromagnets and magnetic materials.

4. The ladder-suspended magnetorheological oscillator structure according to claim 1, characterized in that: Thrust ball bearings (13) are provided on both sides of the flywheel (10). The thrust ball bearings (13) are sleeved on the ball screw (11). The bearing tight ring of the thrust ball bearing (13) is connected to the flywheel (10), and the bearing loose ring is connected to the limit plate.

5. The ladder-suspended magnetorheological oscillator structure according to claim 1, characterized in that: Two threaded sections of the ball screw (11) with opposite thread directions are respectively sleeved with at least one pair of flywheels (10).

6. The ladder-suspended magnetorheological oscillator structure according to claim 1, characterized in that: A spiral pipe (18) is provided axially around the wall of the cavity between the inner sleeve (7) and the outer sleeve (8) in the outer sleeve (8), and the magnetorheological fluid (16) circulates in the cavity and the spiral pipe (18).

7. The ladder-suspended magnetorheological oscillator structure according to claim 1, characterized in that: Pads (4) are provided between the contact surfaces of the top and bottom of the ladder (1) and the tower body. The material of the pads (4) is selected from one or more of polytetrafluoroethylene, ultra-high molecular weight polyethylene, and polyurethane.

8. A single-tube tower vibration reduction method, characterized in that: The method uses the substructure according to any one of claims 1 to 7 to perform vibration reduction of a single-tube tower, and the method comprises the following steps: In normal use, the electromagnet is energized, and there is a magnetic attraction between the magnetic attraction part (5) in the ladder and the magnetic attraction part (6) in the tower. The ladder (1) is adsorbed on one side of the inner wall of the single-tube tower, and the shape memory alloy springs (2) and the cables (9) on both sides of the ladder (1) are in a taut state. When abnormal vibration occurs, the electromagnet is powered off, the ladder (1) is detached, and under the pulling force of the shape memory alloy spring (2), it returns to the center from the edge of the single-tube tower; When the main structure of the single-tube tower vibrates, under the action of the shape memory alloy spring (2), the ladder (1) moves in the opposite direction to the structural vibration direction, generating an inertial force in the opposite direction to the vibration direction of the single-tube tower. The ladder (1) follows the vibration of the single-tube tower and reacts the inertial force generated by the relative movement to the main structure of the single-tube tower, so that the vibration response of the main structure is attenuated and controlled. When the main structure of the single-tube tower vibrates, the inner sleeve (7) drives the ball screw (11) and the flywheel (10) to rotate, converting the translational kinetic energy into rotational kinetic energy, which has a mass amplification effect to absorb and dissipate the vibration energy of the ladder (1); at the same time, the magnetorheological inertial damper (3) and the series-connected cable (9) work together to effectively reduce the relative displacement between the ladder (1) and the single-tube tower; The inner piston (14) and the outer piston (15) move linearly under the drive of the inner sleeve (7), forcing the magnetorheological fluid (16) to flow along the spiral pipe (18) into the cavity between the inner sleeve (7) and the outer sleeve (8), forming a circulation flow of the magnetorheological fluid (16) in the cavity and the spiral pipe (18). The inertial amplification effect generated thereby also causes the magnetorheological inertial damper (3) to generate inertial force, further consuming the vibration energy of the ladder (1); When the magnetorheological fluid (16) passes through the gap between the inner piston (14) and the excitation coil (17), a damping force is generated, thereby consuming the relative motion energy between the ladder (1) and the single-tube tower.

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