A low-frequency tuned mass system with variable stiffness-inertia enhancement and vibration absorption method

Abstract

The present invention relates to a low-frequency tuned mass system and vibration absorption method with variable stiffness and inertia enhancement. The upper portion of a recovery unit is provided with an arcuate groove, on which a rack is provided. The rotating element of the inertial unit meshes with the rack via a gear set. The rotating shaft of the rotating element is connected to the rotating shaft of the gear set via a connecting frame. The connecting frame is connected to the upper structure. The recovery unit is connected to a tuning vibration absorption unit. A fixed rack track is connected to the lower structure. A slide rail is provided next to the fixed rack track. The tuning vibration absorption unit is mounted on the slide rail. The tuning vibration absorption unit is provided with a fixed shaft. The rotating element of the inertial unit flywheel is fixedly connected to a gear. The rotating element and the gear are sleeved on the fixed shaft. The gear meshes with the fixed rack track. A first permanent magnet is embedded in the rotating element, and a second permanent magnet is disposed in a cavity of the rotating element. Compared with the prior art, the present invention achieves multi-band widening of the tuning frequency band, energy absorption and vibration reduction of low-frequency offset, and adaptive recovery of the tuned mass system.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering and relates to a low-frequency tuned mass system with variable stiffness and inertia enhancement and a vibration absorption method. Background Art

[0002] Tuned vibration absorption technology is an effective means of controlling structural vibrations. However, improving the performance of traditional tuned vibration absorption systems relies on the addition of additional tuning mass. This is limited by the practical space and cost constraints of installation in actual projects, which limits the performance improvement and application of traditional dynamic vibration absorption technology. Furthermore, traditional tuned vibration absorption systems typically use springs and other stiffness elements to create a recovery mechanism, which makes it difficult to adapt to the permanent residual deformation of the tuned vibration absorption mass caused by friction within the device. Therefore, developing methods to increase the mass efficiency of dynamic tuned vibration absorption systems and their self-restoring mechanisms is crucial for improving the performance of tuned vibration absorption systems.

[0003] With the rapid advancement of engineering technology, the vibration problems faced by various engineering structures are becoming increasingly complex and diverse. Low-frequency vibration, in particular, poses a serious threat to the stability, safety, and service life of structures. Traditional tuned vibration absorption systems often suffer from limitations such as limited tuning range and insufficient energy efficiency when dealing with low-frequency vibration. Therefore, the exploration of new vibration control mechanisms and technologies is of paramount importance.

[0004] Patent CN119122123A discloses a coaxial counter-rotating gear set type inertia damping negative stiffness ternary resonance unit and super foundation. The driving outer cylinder is sleeved on the screw, the nut and the driving gear are sleeved on the screw, the driving gear is fixedly connected to the nut, and the driving gear is meshed with the first counter-rotating gear and the second counter-rotating gear. The second counter-rotating gear is sleeved on the central shaft through the second rotating cylinder and fixedly sleeved on the second rotating cylinder. The first counter-rotating gear is sleeved on the central shaft through the first rotating cylinder and fixedly sleeved on the first rotating cylinder. The first rotating cylinder and the second rotating cylinder are arranged inside and outside. The central shaft is fixedly connected to the base. The first inertia disk is fixedly connected to the first rotating cylinder. The second inertia disk is fixedly connected to the second rotating cylinder. An energized coil is provided between the first inertia disk and the second inertia disk. The energized coils are arranged in pairs and fixedly connected to the inertia disk. However, this patent utilizes a ternary resonance unit in combination with different forms of resonant masses to form a local resonance unit based on metamaterials. The resonance unit is only connected to a single-port driving outer cylinder, making it difficult to achieve dual / multiple inertial mass efficiency enhancement and inertial energy absorption, thereby affecting the dissipation and absorption efficiency of vibration energy. In addition, the recovery characteristics of the resonance unit are only adjusted by a tuning spring, with relatively few adjustable parameters. The adjustment of the recovery characteristics is limited, making it difficult to achieve complex nonlinear behaviors. This patent utilizes the negative stiffness of inertial capacitance damping to achieve energy efficiency enhancement. The technical path of the energized coil requires the consumption of additional electrical energy and energy loss to generate a variable magnetic field, and there are problems with device stability and anti-dynamic interference. In addition, the device has multiple nested and rotating components, and requires high processing accuracy and installation accuracy of each component. There are problems such as poor gear meshing and uneven rotation, which in turn affects the effects of structural stiffness adjustment and vibration energy absorption.

[0005] Patent CN115585221A discloses a rack-and-pinion tuned mass damping inertia container suitable for a wind turbine tower, which includes a mass block, a rigid spring, an inertia element, an eddy current damping device, a track, and a bracket; the track is connected to the bracket; the mass block can move along the track; the rigid spring is respectively connected to the bracket and the mass block and provides elastic force for the movement of the mass block along the track; the inertia element is respectively connected to the mass block and the bracket and drives the flywheel to rotate through a gear assembly to increase the adjustable inertia range of the tuned mass system; the eddy current damping device is respectively connected to the mass block and the bracket and provides damping force for the movement of the mass block along the track. However, this patent only utilizes the inertial adjustment properties of the apparent mass of the inertial element, ignores the inertial characteristics of the physical mass of the inertial element itself and its objective influence on the design of the device, and cannot achieve dual / multiple inertial mass synergy and inertial energy absorption; tuned vibration absorption depends on a larger tuning mass, and the motion mode of the large-mass tuning system is difficult to be excited, the tunable frequency range is limited, and the low-frequency energy absorption characteristics are restricted; the stiffness adjustment path of this patent only relies on rigid springs, lacks adaptive adjustment of multi-stage variable stiffness, and its recovery characteristics cannot be adjusted after the stiffness is fixed, which cannot meet the needs of adaptive vibration reduction. Summary of the Invention

[0006] The purpose of the present invention is to overcome at least one of the defects of the above-mentioned prior art and provide a low-frequency tuned mass system and vibration absorption method with variable stiffness-inertia enhancement. The present invention realizes multi-segment widening of the tuning frequency band, energy absorption and vibration reduction of low-frequency offset, and adaptive recovery of the tuned mass system.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] One of the technical solutions of the present invention is to provide a low-frequency tuned mass system with variable stiffness and inertia enhancement, which includes an adaptive recovery device and an electromagnetic dynamic vibration absorption device connected in an upper and lower manner.

[0009] The adaptive recovery device includes an inertia unit and a recovery unit. An arc-shaped groove is provided on the upper portion of the recovery unit, and a rack is provided on the arc-shaped groove. The inertia unit includes a rotating body and a gear set. The rotating body is engaged with the rack through the gear set. The rotating shaft of the rotating body is connected to the rotating shaft of the gear set through a connecting frame. The connecting frame is connected to the upper structure.

[0010] The electromagnetic dynamic vibration absorption device includes a tuned vibration absorption unit, a fixed shaft, an inertia container, a negative stiffness control unit and a fixed rack track. The recovery unit is connected to the tuned vibration absorption unit, and the fixed rack track is connected to the lower structure. A slide rail is provided next to the fixed rack track. The tuned vibration absorption unit is mounted on the slide rail. A fixed shaft is provided on the tuned vibration absorption unit. The inertia container includes a flywheel, which includes a rotating body and a gear. The rotating body is fixedly connected to the gear. The rotating body and the gear are sleeved on the fixed shaft. The gear is meshed with the fixed rack track. The negative stiffness control unit includes a first permanent magnet and a second permanent magnet. The first permanent magnet is embedded in the rotating body, and the second permanent magnet is provided in the cavity of the rotating body.

[0011] As a preferred technical solution, the upper structure and the lower structure adopt rigid supports or beam-slab components.

[0012] Furthermore, the adaptive recovery device further comprises a damping unit, a fixed end of the damping unit being vertically fixedly connected to the upper structure, and an output end of the damping unit being vertically fixedly connected to the connecting frame.

[0013] Furthermore, the gear set includes a driving pinion, a driven large gear and a driven pinion, the rotating body of the inertial unit is fixedly connected to the driven pinion, the driven pinion is meshed with the driven large gear, the driven large gear is fixedly connected to the driving pinion, the driving pinion is meshed with the rack, the rotating shafts of the rotating body and the driven pinion are connected to the connecting frame through a rotating bearing, and the rotating shafts of the driven large gear and the driving pinion are connected to the connecting frame through a rotating bearing.

[0014] Furthermore, the recovery unit is fixedly mounted on the tuned vibration absorbing unit and moves horizontally with the tuned vibration absorbing unit. The recovery unit with the arc-shaped rack as the core moves horizontally with the tuned vibration absorbing unit while causing the inertial unit to rotate through gear meshing. The centroid of the inertial unit moves vertically up and down along the axis of the damping unit, compressing the damping unit.

[0015] Furthermore, the fixed rack rail is fixedly mounted on the lower structure, and a fixed shaft is fixedly mounted on the tuning vibration absorbing unit.

[0016] Furthermore, the inertia container includes a driving flywheel and a driven flywheel, the driving flywheel includes a driving rotor and a driving gear, the driven flywheel includes a driven rotor and a driven gear, the driving rotor is fixedly connected to the driving gear, the driven rotor is fixedly connected to the driven gear, and the driving rotor, driving gear, driven rotor and driven gear are sleeved on a fixed shaft via a rotating bearing.

[0017] Furthermore, a rack is provided on the inner surface of the active rotating body, a cross frame is fixedly installed on the fixed shaft inside the active rotating body, a transmission gear is installed on the cross frame, the active gear is engaged with the fixed rack track, the rack is engaged with the transmission gear, and the transmission gear is engaged with the driven gear.

[0018] Furthermore, the first permanent magnets are symmetrically distributed in pairs and embedded in the active rotating body, with the same magnetic poles in the horizontal direction and opposite magnetic poles in the vertical direction. The second permanent magnets are fixedly mounted on the fixed shaft and are located in the magnetic field of the first permanent magnet. The magnetic poles at both ends of the second permanent magnet are opposite to the magnetic poles of the first permanent magnet in the same horizontal direction. The negative stiffness control unit with magnetic pole control as the core is used to control the dynamic tuning vibration absorption unit with the inertia container as the core and provide negative stiffness.

[0019] As a preferred technical solution, in the adaptive restoring device, the angle or curvature of the rack of the arc-shaped groove of the restoring unit can be adjusted according to design requirements to achieve adjustment of the stiffness characteristics of the restoring unit.

[0020] As a preferred technical solution, in the electromagnetic dynamic vibration absorption device, the negative stiffness characteristics of the negative stiffness control unit can be adjusted by adjusting the arrangement angle between the magnetic poles. The negative stiffness control unit can drive the flywheel via gears or chains. The apparent mass adjustment of the inertia coefficient of the inertia container can be achieved by designing the radii of the driving flywheel, transmission gears, and driven gears. Theoretically, multiple groups of transmission gears and driven flywheels can be connected in series to achieve multi-stage amplification of the apparent mass. The multi-stage amplification and efficiency enhancement of the flywheel's apparent mass can be achieved through coaxial rotation or non-coaxial rotation.

[0021] Furthermore, in the initial equilibrium position, the second permanent magnet is located on the central axis of the first permanent magnet which is symmetrical in the horizontal direction, and the driving pinion of the gear set is located at the lowest point of the arc-shaped groove.

[0022] One of the technical solutions of the present invention is to provide a low-frequency tuned vibration absorption method with variable stiffness-inertia synergy, which uses the system to absorb vibration of the main structure, and the method includes the following steps:

[0023] When the system is working, the tuning vibration absorbing unit and the fixed rack track produce relative horizontal displacement to achieve dynamic tuning function;

[0024] The tuning vibration absorbing unit generates translational motion to drive the active flywheel to rotate. At the same time, the flywheel will move horizontally along the fixed shaft fixed to the tuning vibration absorbing unit. The physical mass of the flywheel acts as a tuning mass to achieve efficiency enhancement.

[0025] When the system is in its original equilibrium state, for a multi-stage variable stiffness electromagnetic dynamic vibration absorption device, the second permanent magnet is located on the central axis of the first permanent magnet, which is symmetrical in the horizontal direction. At this time, the magnetic field state is in an arbitrary equilibrium position. The maintenance of the arbitrary equilibrium position (taking into account the influence of secondary factors that may destroy the arbitrary equilibrium) and recovery rely on the inertia unit being at the lowest point of the recovery unit.

[0026] When the system is excited by external vibration, the tuned vibration absorption unit is displaced and the active flywheel rotates. At this time, the magnetic field of the first permanent magnet also rotates with the active flywheel, breaking the original balanced magnetic field of the first and second permanent magnets. Due to the greater attraction on one side of the asymmetric opposite poles of the first and second permanent magnets after rotation, negative stiffness characteristics are generated on the active flywheel, thereby driving the horizontal displacement of the tuned vibration absorption unit.

[0027] When the rotation angle reaches a state where the magnetic poles of the first permanent magnet and the magnetic poles of the second permanent magnet are opposite to each other, the magnetic field is in a static equilibrium state, that is, the maximum value of the negative stiffness range; the inertia unit climbs a certain height along the arc groove of the restoring unit;

[0028] If the active flywheel rotation angle exceeds the maximum value of the negative stiffness range, the static balance of the magnetic field is destroyed, and the first and second permanent magnets exhibit positive stiffness characteristics due to the opposite poles attracting each other and the same poles repelling each other, thus limiting the horizontal displacement of the tuned vibration absorbing unit.

[0029] When the rotation angle reaches a state where the magnetic poles of the first permanent magnet and the magnetic poles of the second permanent magnet are facing each other, the magnetic field is in a random equilibrium state, that is, the maximum value of the positive stiffness range; the inertia unit climbs to the maximum height along the arc groove of the restoring unit;

[0030] The rotation of the active flywheel will also drive the coaxial rotation of the driven flywheel through the transmission gear, realizing the secondary amplification of the flywheel inertia;

[0031] Because the tuned vibration absorption unit is fixedly connected to the arc-shaped rack of the restoring unit, the restoring unit will produce horizontal displacement relative to the centroid of the inertial unit. At this time, the arc-shaped rack will drive the gear of the inertial unit to rotate. As the inertial unit rotates, its centroid will be raised by the arc-shaped rack, compressing the output end of the damping unit. The two ends of the damping unit will produce relative displacement and relative velocity, realizing nonlinear damping energy dissipation.

[0032] Based on its own weight, the inertia unit applies normal pressure to the restoration unit through the arc-shaped rack. The horizontal component of the normal pressure causes the tuned vibration absorption unit to move horizontally. When the tuned vibration absorption unit moves back to the equilibrium state from the horizontal maximum displacement position, the positive and negative stiffness ranges of the magnetic field are swapped, preferentially exhibiting the negative stiffness characteristics that promote the restoration movement of the tuned vibration absorption unit, thereby promoting the tuned vibration absorption unit to return to its initial equilibrium position.

[0033] As a preferred technical solution, during the design process, the gear ratio of the active flywheel and the fixed rack track and the maximum stroke of the damping unit output are designed to limit the maximum horizontal displacement of the tuned vibration absorbing unit to not exceed the maximum value of the positive stiffness range.

[0034] As a preferred technical solution, assuming that the physical mass of the inertial unit is G, the surface equation of the restoration unit is f(x), x represents the horizontal displacement of the tuned vibration absorbing unit relative to the inertial unit, when the system is in the initial equilibrium state, x = 0, the inclination angle at any position of the surface is θ, and tanθ = f'(x); when relative displacement occurs, the restoring force exerted by the inertial unit on the restoration unit is F x =G / cosθ×sinθ=Gtanθ=Gf'(x).

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) Dual inertial mass synergistic mechanism and inertial energy absorption path. The present invention makes full use of dual inertial mass and utilizes the energy storage and release mechanism of the inertial container to adjust the energy distribution of the system. In the traditional damping energy dissipation process, the deformation generated by the damping unit is relatively limited, and its energy dissipation effect is limited to a certain extent. However, the present invention introduces an inertial container unit into the adaptive recovery device and utilizes the rotation of the inertial mass to make the adaptive recovery device exhibit negative stiffness characteristics, thereby achieving a local amplification effect on the deformation of the damping unit and dissipating more vibration energy. In a low-frequency vibration environment, the traditional tuned vibration absorption system is often unable to effectively absorb vibration energy due to the high tuning frequency. The present invention introduces an inertial container into the electromagnetic power vibration absorption device to achieve the amplification of the apparent mass of the electromagnetic power vibration absorption device, thereby reducing the tuning vibration absorption frequency. As the system tuning frequency decreases, the system can better match the frequency of the low-frequency vibration source, and the energy absorption capacity of the system in the low-frequency range is greatly improved.

[0037] (2) Adjustable vertical adaptive recovery mechanism of the tuned mass system. The traditional tuned vibration absorption system mainly relies on springs and other stiffness elements to achieve recovery characteristics, while the present invention adopts a new recovery mechanism form; the adaptive recovery device generates a restoring force with the help of the inertial unit's own weight. When the system is disturbed and displaced, the inertial unit's own weight acts on the gear meshing with the arc-shaped rack, and the gear transmission causes the tuned vibration absorption unit to return to the equilibrium position; by changing the angle or curvature of the arc-shaped rack, the motion trajectory and force state of the gear on the arc-shaped rack can be effectively controlled, thereby realizing flexible adjustment of the stiffness characteristics of the adaptive recovery device; this method of adjusting stiffness based on geometric parameters provides a high degree of flexibility for optimizing the dynamic characteristics of the system, enabling the system to accurately adapt to various complex working conditions and changing vibration environments, greatly expanding the application potential of the system in engineering practice;

[0038] (3) Multi-stage variable stiffness-inertia-enhanced low-frequency tuned mass system. Traditional tuned vibration absorption relies on bulky tuning mass. The motion mode of the large-mass tuning system is difficult to be excited. The negative stiffness mechanism shows superior characteristics, which can enable the system to achieve tuned vibration absorption function in a wider frequency range. The electromagnetic dynamic vibration absorption device realizes the innovation of multi-stage variable stiffness mechanism through the specific arrangement of magnetic poles. The arrangement of magnetic poles is designed to enable the electromagnetic dynamic vibration absorption device to generate negative stiffness and provide a certain positive stiffness. When the tuned vibration absorption unit is excited by vibration, The electromagnetic power vibration absorption device preferentially exhibits negative stiffness characteristics, driving the inertial container flywheel to rotate and the tuned vibration absorption unit to move horizontally; when the translational displacement exceeds the negative stiffness range, the electromagnetic power vibration absorption device exhibits positive stiffness characteristics, providing appropriate restoring force and constraint force, effectively limiting the horizontal displacement of the tuned vibration absorption unit, and ensuring the stability and vibration absorption effect of the system; at the same time, an innovative form of inertia enhancement is implemented, that is, the physical mass of the inertial container itself is used to achieve tuned vibration absorption enhancement; the physical mass of the inertial container will generate inertial force during the vibration process, thereby increasing the tuning mass and enhancing the vibration absorption effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the three-dimensional structure of a low-frequency tuned mass system with variable stiffness-inertia enhancement according to an embodiment of the present invention;

[0040] Figure 2 Schematic diagram of the cross-sectional structure of a low-frequency tuned mass system with variable stiffness-inertia enhancement according to an embodiment of the present invention;

[0041] Figure 3 Schematic diagram of the mechanism of the negative stiffness interval in an embodiment of the present invention;

[0042] Figure 4 Schematic diagram of the structure of the electromagnetic dynamic vibration absorption device in an embodiment of the present invention.

[0043] Description of the marks in the figure:

[0044] 1—superstructure, 2—damping unit, 3—inertia unit, 4—rotating bearing, 5—restoring unit, 6—tuned vibration absorbing unit, 7—fixed shaft, 8—driving flywheel, 9—driven flywheel, 10—fixed rack track, 11—slide rail, 12—second permanent magnet, 13—first permanent magnet, 14—transmission gear. DETAILED DESCRIPTION

[0045] 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.

[0046] 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.

[0047] 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.

[0048] Example:

[0049] A low-frequency tuned mass system with variable stiffness-inertia enhancement, such as Figure 1 and Figure 2 As shown, it includes an adaptive recovery device and an electromagnetic dynamic vibration absorption device connected up and down.

[0050] The adaptive recovery device includes an inertia unit 3 and a recovery unit 5. An arc-shaped groove is provided on the upper portion of the recovery unit 5, and a rack is provided on the arc-shaped groove. The inertia unit 3 includes a rotating body and a gear set. The rotating body is engaged with the rack through the gear set. The rotating shaft of the rotating body is connected to the rotating shaft of the gear set through a connecting frame. The connecting frame is connected to the upper structure 1.

[0051] The electromagnetic dynamic vibration absorption device includes a tuned vibration absorption unit 6, a fixed shaft 7, an inertia container, a negative stiffness control unit, and a fixed rack track 10. The recovery unit 5 is connected to the tuned vibration absorption unit 6, and the fixed rack track 10 is connected to the lower structure. A slide rail 11 is provided next to the fixed rack track 10. The tuned vibration absorption unit 6 is mounted on the slide rail 11. The tuned vibration absorption unit 6 is provided with a fixed shaft 7. The inertia container includes a flywheel, which includes a rotating body and a gear. The rotating body is fixedly connected to the gear. The rotating body and the gear are sleeved on the fixed shaft 7. The gear is meshed with the fixed rack track 10. The negative stiffness control unit includes a first permanent magnet 13 and a second permanent magnet 12. The first permanent magnet 13 is embedded in the rotating body, and the second permanent magnet 12 is provided in the cavity of the rotating body.

[0052] The upper structure 1 and the lower structure adopt rigid supports or beam-slab components. In this embodiment, the upper structure 1 is preferably a rigid support (I-beam), and the lower structure is preferably a beam-slab component (floor slab);

[0053] The adaptive recovery device further comprises a damping unit 2, the fixed end of the damping unit 2 being vertically fixedly connected to the upper structure 1, and the output end being vertically fixedly connected to the connecting frame;

[0054] The gear set includes a driving pinion, a driven large gear, and a driven pinion. The rotating body of the inertia unit 3 is fixedly connected to the driven pinion, the driven pinion meshes with the driven large gear, the driven large gear is fixedly connected to the driving pinion, and the driving pinion meshes with the rack. The rotating shafts of the rotating body and the driven pinion are connected to the connecting frame via a rotating bearing 4. The rotating shafts of the driven large gear and the driving pinion are connected to the connecting frame via a rotating bearing 4.

[0055] In this embodiment, the damping unit 2 is a damper, and the rotating body of the inertia unit 3 is a turntable. The fixed end of the damping unit 2 is vertically fixedly installed under the upper structure 1, and the output end is vertically downward. A pair of damping units 2 and a connecting frame are installed on the outside of a pair of rotating bodies. The pair of rotating bodies are installed on both sides of a driven pinion, and a pair of driving pinions are installed on both sides of a driven large gear.

[0056] The restoring unit 5 is fixedly mounted on the tuned vibration absorbing unit 6 and can move horizontally with the tuned vibration absorbing unit 6. The restoring unit 5, with the arc-shaped rack as its core, moves horizontally with the tuned vibration absorbing unit 6 while causing the inertial unit 3 to rotate through gear meshing. The centroid of the inertial unit 3 moves vertically up and down along the axis of the damping unit 2, compressing the damping unit 2.

[0057] In this embodiment, the restoration unit 5 and the tuning vibration absorbing unit 6 are both made of mass blocks, made of steel or concrete, preferably made of steel, and a pair of restoration units 5 are vertically fixedly installed on both sides of the top of the tuning vibration absorbing unit 6;

[0058] The fixed rack rail 10 is fixedly mounted on the lower structure, and the fixed shaft 7 is fixedly mounted on the tuning vibration absorbing unit 6;

[0059] In this embodiment, the slide rail 11 is a smooth slide rail that provides vertical support for the tuning vibration absorbing unit 6 to ensure its horizontal motion. The smooth contact surface can reduce friction between the mass block and the slide rail to ensure that a preset phase difference is maintained between the tuning vibration absorbing unit 6 and the fixed rack rail 10. A pair of fixed rack rails 10 are vertically fixedly mounted on the lower structure, and the slide rail 11 is horizontally mounted between the pair of fixed rack rails 10. A pair of fixed shafts 7 are horizontally fixedly mounted on both sides of the tuning vibration absorbing unit 6, and a pair of inertia containers are mounted on both sides of the tuning vibration absorbing unit 6.

[0060] like Figure 4 As shown, the inertia container includes a driving flywheel 8 and a driven flywheel 9. The driving flywheel 8 includes a driving rotor and a driving gear. The driven flywheel 9 includes a driven rotor and a driven gear. The driving rotor is fixedly connected to the driving gear, and the driven rotor is fixedly connected to the driven gear. The driving gear is engaged with a fixed rack track 10. The driving rotor, the driving gear, the driven rotor and the driven gear are sleeved on the fixed shaft 7 through a rotating bearing 4.

[0061] In this embodiment, the active rotor is a rotary drum with one side closed, and the driven rotor is a turntable. A driven rotor is mounted on the unclosed side of the active rotor. One side of the closed surface of the active rotor is fixedly connected to the active gear outside the inner cavity, and one side of the driven rotor is fixedly connected to the driven gear toward the inner cavity of the active rotor.

[0062] A rack is provided on the inner surface of the active rotating body. A cross frame is fixedly mounted on the fixed shaft 7 inside the active rotating body. A transmission gear 14 is mounted on the cross frame. The rack meshes with the transmission gear 14, and the transmission gear 14 meshes with the driven gear.

[0063] In this embodiment, a horizontal frame is fixedly mounted on the fixed shaft 7 in the inner cavity of the active rotating body, and a pair of transmission gears 14 are horizontally mounted on both sides of the horizontal frame. The pair of transmission gears 14 are horizontally meshed with the driven gear.

[0064] The first permanent magnets 13 are symmetrically distributed in pairs and embedded in the active rotating body, with the same magnetic poles in the horizontal direction and opposite magnetic poles in the vertical direction. The second permanent magnets 12 are fixedly mounted on the fixed shaft 7 and are located in the magnetic field of the first permanent magnets 13. The magnetic poles at both ends of the second permanent magnets 12 are opposite to the magnetic poles of the first permanent magnets 13 in the same horizontal direction. The negative stiffness control unit with magnetic pole control as the core is used to control the dynamic tuning vibration absorption unit with the inertia container as the core and provide negative stiffness.

[0065] In this embodiment, four first permanent magnets 13 are symmetrically distributed in pairs and embedded in the active rotating body. Two S (N) poles are symmetrically installed on both sides of the vertical axis above the horizontal axis, and two N (S) poles are symmetrically installed on both sides of the vertical axis below the horizontal axis. The second permanent magnet 12 is vertically fixed on the horizontal frame. The upper side of the second permanent magnet 12 is the N (S) pole, and the lower side is the S (N) pole.

[0066] In the adaptive restoring device, the angle or curvature of the rack of the arc-shaped groove of the restoring unit 5 can be adjusted according to the design requirements to achieve the adjustment of the stiffness characteristics of the restoring unit 5;

[0067] In the electromagnetic dynamic vibration absorption device, the negative stiffness characteristics of the negative stiffness control unit can be adjusted by adjusting the arrangement angle between the magnetic poles. The driving effect of the negative stiffness control unit on the flywheel can be achieved through gears or chains. The apparent mass adjustment of the inertia coefficient of the inertia container can be achieved through the radius design of the active flywheel 8, the transmission gear 14 and the driven gear 9. In theory, multiple groups of transmission gears 14 and driven flywheels 9 can be connected in series to achieve multi-stage amplification of the apparent mass. The multi-stage amplification and efficiency enhancement of the flywheel's apparent mass can be achieved in the form of coaxial rotation or non-coaxial rotation.

[0068] A low-frequency tuned vibration absorption method with variable stiffness and inertia enhancement is provided, which uses the above system to absorb vibration of the main structure. The specific steps are as follows:

[0069] When the system is working, the tuning vibration absorbing unit 6 and the fixed rack track 10 produce relative horizontal displacement to achieve the dynamic tuning function;

[0070] The tuning vibration absorbing unit 6 generates translational motion to drive the active flywheel 8 to rotate. At the same time, the flywheel will generate horizontal movement along the fixed shaft 7 fixedly mounted on the tuning vibration absorbing unit 6. The physical mass of the flywheel acts as a tuning mass to achieve efficiency enhancement.

[0071] When the system is in its original equilibrium state, for the multi-stage variable stiffness electromagnetic dynamic vibration absorption device, the second permanent magnet 12 is located on the central axis of the first permanent magnet 13, which is symmetrical in the horizontal direction. At this time, the magnetic field state is in an arbitrary equilibrium position. The maintenance of the arbitrary equilibrium position (taking into account the influence of secondary factors that may destroy the arbitrary equilibrium) and the restoration of the arbitrary equilibrium position rely on the inertia unit 3 being at the lowest point of the recovery unit 5.

[0072] like Figure 3 As shown, when the system is excited by external vibration, assuming that the tuned vibration absorbing unit 6 is displaced to the left and the active flywheel 8 rotates counterclockwise (viewed from the front to the back), the S pole on the upper right of the first permanent magnet 13 approaches the N pole of the second permanent magnet 12, while the S pole on the upper left of the first permanent magnet 13 moves away from the N pole of the second permanent magnet 12, so that the S pole on the upper right exhibits a greater attractive force, thereby exhibiting a negative stiffness characteristic (similarly, the corresponding characteristics of the S pole below the second permanent magnet 12 are the same, and the forces are superimposed);

[0073] When the rotation angle reaches the state where the S pole at the upper right of the first permanent magnet 13 and the N pole of the second permanent magnet 12 are opposite to each other, the magnetic field is in a static equilibrium state, that is, the maximum value of the negative stiffness range; the inertia unit 3 climbs a certain height along the arc-shaped groove of the recovery unit 5;

[0074] If the rotation angle of the first permanent magnet 13 exceeds the maximum value of the negative stiffness range, the static balance of the magnetic field is destroyed, and the S pole at the upper right of the first permanent magnet 13 and the N pole of the second permanent magnet 12 attract each other, while the N pole at the lower right of the first permanent magnet 13 and the N pole of the second permanent magnet 12 repel each other, showing a positive stiffness characteristic that restores the static balance of the magnetic field (similarly, the corresponding characteristic of the S pole below the second permanent magnet 12 is the same, and the forces are superimposed);

[0075] When the rotation angle reaches the state where the N pole at the lower right of the first permanent magnet 13 and the N pole of the second permanent magnet 12 are facing each other, the magnetic field is in a random equilibrium state, that is, the maximum value of the positive stiffness range; the inertia unit 3 climbs to the maximum height along the arc-shaped groove of the recovery unit 5;

[0076] When the tuning vibration absorbing unit 6 is displaced to the right due to vibration, the magnetic field state and characteristics are similar to the above process;

[0077] The rotation of the active flywheel 8 will also drive the coaxial rotation of the driven flywheel 9 through the transmission gear 14, realizing the secondary amplification of the flywheel inertia;

[0078] Since the tuned vibration absorbing unit 6 is fixedly connected to the arc-shaped rack of the restoring unit 5, the restoring unit 5 will produce a horizontal displacement relative to the centroid of the inertial unit 3. At this time, the arc-shaped rack will drive the gear of the inertial unit 3 to rotate. As the inertial unit 3 rotates, its centroid will be raised by the arc-shaped rack, compressing the output end of the damping unit 2. The two ends of the damping unit 2 will produce relative displacement and relative velocity, realizing nonlinear damping energy dissipation.

[0079] Based on its own weight, the inertia unit 3 applies a normal pressure to the recovery unit 5 through the arc-shaped rack. The horizontal component of the normal pressure causes the tuned vibration absorbing unit 6 to move horizontally. When the tuned vibration absorbing unit 6 recovers from the horizontal maximum displacement position to the system equilibrium state, the positive and negative stiffness intervals of the magnetic field are swapped, preferentially exhibiting a negative stiffness characteristic that promotes the recovery of the tuned vibration absorbing unit 6, thereby promoting the tuned vibration absorbing unit 6 to return to the initial equilibrium position where the driving pinion of the gear set is at the lowest point of the arc-shaped groove.

[0080] During the design process, the gear ratio of the active flywheel 8 and the fixed rack track 10, as well as the maximum stroke of the output end of the damping unit 2, are designed to limit the maximum horizontal displacement of the tuned vibration absorbing unit 6 to not exceed the maximum value of the positive stiffness range (i.e., the N pole at the lower right of the first permanent magnet 13 and the N pole of the second permanent magnet 12 are facing each other).

[0081] Assume that the physical mass of the inertial unit 3 is G, and the surface equation of the restoration unit 5 is f(x), where x represents the horizontal displacement of the tuned vibration absorbing unit 6 relative to the inertial unit 3. When the system is in the initial equilibrium state, x = 0, the inclination angle at any position of the surface is θ, and tanθ = f'(x); when relative displacement occurs, the restoring force exerted by the inertial unit 3 on the restoration unit 5 is F x =G / cosθ×sinθ=Gtanθ=Gf'(x).

[0082] The present invention innovates a dual inertial mass synergy mechanism and inertial energy absorption path. It regulates energy distribution by storing and releasing energy in the inertial container, introduces the inertial container unit 3 to achieve deformation amplification and energy dissipation of the damping unit, and introduces the inertial container's own weight and apparent mass to reduce the tuned vibration absorption frequency, improve low-frequency energy absorption capacity, and expand application potential. The present invention adopts a new vertical adaptive recovery mechanism, relying on the return balance of the inertial container unit 3's own weight and the arc-shaped rack and pinion transmission, and adjusts the stiffness based on geometric parameters to adapt to complex working conditions and vibration environments. The present invention innovates a low-frequency tuned mass system with multi-stage variable stiffness-inertia synergy, using a negative stiffness mechanism to broaden the tuning range. The electromagnetic dynamic vibration absorption device innovates a variable stiffness mechanism, combined with the inertial synergy of the physical mass of the inertial container to ensure system stability and vibration absorption effect.

[0083] 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 low-frequency tuned mass system with variable stiffness-inertia enhancement, characterized in that: The system includes an adaptive recovery device and an electromagnetic dynamic vibration absorption device connected up and down. The adaptive recovery device comprises an inertia unit (3) and a recovery unit (5), wherein an arcuate groove is provided on the upper portion of the recovery unit (5), and a rack is provided on the arcuate groove. The inertia unit (3) comprises a rotating body and a gear set, wherein the rotating body is meshed with the rack through the gear set, and the rotating shaft of the rotating body is connected to the rotating shaft of the gear set through a connecting frame, and the connecting frame is connected to the upper structure (1). The electromagnetic dynamic vibration absorbing device comprises a tuning vibration absorbing unit (6), a fixed shaft (7), an inertia container, a negative stiffness control unit and a fixed rack track (10), the recovery unit (5) is connected to the tuning vibration absorbing unit (6), the fixed rack track (10) is connected to the lower structure, a slide rail (11) is provided next to the fixed rack track (10), the tuning vibration absorbing unit (6) is mounted on the slide rail (11), a fixed shaft (7) is provided on the tuning vibration absorbing unit (6), the inertia container comprises a flywheel, the flywheel comprises a rotating body and a gear, the rotating body is fixedly connected to the gear, the rotating body and the gear are sleeved on the fixed shaft (7), the gear is meshed with the fixed rack track (10), the negative stiffness control unit comprises a first permanent magnet (13) and a second permanent magnet (12), the first permanent magnet (13) is embedded in the rotating body, and the second permanent magnet (12) is provided in the cavity of the rotating body; The adaptive recovery device further comprises a damping unit (2), wherein a fixed end of the damping unit (2) is vertically fixedly connected to the upper structure (1), and an output end is vertically fixedly connected to the connecting frame; The inertia container includes a driving flywheel (8) and a driven flywheel (9), the driving flywheel (8) includes a driving rotor and a driving gear, the driven flywheel (9) includes a driven rotor and a driven gear, the driving rotor is fixedly connected to the driving gear, the driven rotor is fixedly connected to the driven gear, and the driving rotor, the driving gear, the driven rotor and the driven gear are sleeved on the fixed shaft (7) through a rotating bearing (4); The first permanent magnets (13) are symmetrically distributed in pairs and embedded in the active rotating body, with the same magnetic poles in the horizontal direction and opposite magnetic poles in the vertical direction. The second permanent magnets (12) are fixedly mounted on the fixed shaft (7) and are located in the magnetic field of the first permanent magnet (13). The magnetic poles at both ends of the second permanent magnet (12) are opposite to the magnetic poles of the first permanent magnet (13) in the same horizontal direction.

2. A low-frequency tuned mass system with variable stiffness and inertia enhancement according to claim 1, characterized in that: The gear set comprises a driving pinion, a driven large gear and a driven pinion, the rotating body of the inertial unit (3) is fixedly connected to the driven pinion, the driven pinion is meshed with the driven large gear, the driven large gear is fixedly connected to the driving pinion, the driving pinion is meshed with the rack, the rotating shafts of the rotating body and the driven pinion are connected to the connecting frame via a rotating bearing (4), and the rotating shafts of the driven large gear and the driving pinion are connected to the connecting frame via a rotating bearing (4).

3. The low-frequency tuned mass system with variable stiffness and inertia enhancement according to claim 1, characterized in that: The recovery unit (5) is fixedly mounted on the tuning vibration absorbing unit (6).

4. The low-frequency tuned mass system with variable stiffness and inertia enhancement according to claim 1, characterized in that: The fixed rack rail (10) is fixedly mounted on the lower structure, and the fixed shaft (7) is fixedly mounted on the tuning vibration absorbing unit (6).

5. The low-frequency tuned mass system with variable stiffness and inertia enhancement according to claim 1, characterized in that: A rack is provided on the inner surface of the active rotating body, a cross frame is fixedly mounted on the fixed shaft (7) in the active rotating body, a transmission gear (14) is mounted on the cross frame, the active gear is meshed with the fixed rack track (10), the rack is meshed with the transmission gear (14), and the transmission gear (14) is meshed with the driven gear.

6. The low-frequency tuned mass system with variable stiffness and inertia enhancement according to claim 1, characterized in that: In the initial equilibrium position, the second permanent magnet (12) is located on the central axis of the first permanent magnet (13) which is symmetrical in the horizontal direction, and the driving pinion of the gear set is located at the lowest point of the arc groove.

7. A low-frequency tuning vibration absorption method with variable stiffness-inertia enhancement, characterized in that: The method uses the system according to any one of claims 1 to 6 to absorb vibration of the main structure, and the method comprises the following steps: The tuning vibration absorbing unit (6) and the fixed rack track (10) generate relative horizontal displacement to achieve a dynamic tuning function; The tuning vibration absorbing unit (6) generates translational motion to drive the active flywheel (8) to rotate, and at the same time, the flywheel generates horizontal motion along with the fixed shaft (7) fixedly mounted on the tuning vibration absorbing unit (6), and the physical mass of the flywheel is used as a tuning mass to achieve efficiency enhancement; When the system is in an original equilibrium state, the second permanent magnet (12) is located on the central axis of the first permanent magnet (13) which is symmetrical in the same horizontal direction. The magnetic field state at this time is an arbitrary equilibrium position. The maintenance and recovery of the arbitrary equilibrium position depends on the inertia unit (3) being at the lowest point of the recovery unit (5). When the system is excited by external vibration, the tuning vibration absorbing unit (6) is displaced and the active flywheel (8) is rotated. At this time, the magnetic field of the first permanent magnet (13) also rotates with the active flywheel (8), and the original equilibrium magnetic field of the first permanent magnet (13) and the second permanent magnet (12) is broken. Due to the greater attraction on one side of the asymmetric opposite poles of the first permanent magnet (13) and the second permanent magnet (12) after rotation, a negative stiffness characteristic is generated on the active flywheel (8), thereby driving the horizontal displacement of the tuning vibration absorbing unit (6); When the rotation angle reaches a state where the magnetic poles of the first permanent magnet (13) and the magnetic poles of the second permanent magnet (12) are opposite to each other, the magnetic field is in a static equilibrium state, i.e., the maximum value of the negative stiffness range; the inertia unit (3) climbs along the arc groove of the recovery unit (5); If the rotation angle of the active flywheel (8) exceeds the maximum value of the negative stiffness range, the static balance of the magnetic field is destroyed, and the first permanent magnet (13) and the second permanent magnet (12) exhibit positive stiffness characteristics due to the different poles on one side attracting and the same poles on the other side repelling, thereby limiting the horizontal displacement of the tuned vibration absorbing unit (6); When the rotation angle reaches a state where the magnetic poles of the first permanent magnet (13) and the magnetic poles of the second permanent magnet (12) are opposite to each other, the magnetic field is in a random equilibrium state, that is, the maximum value of the positive stiffness range; the inertia unit (3) climbs to the maximum height along the arc groove of the recovery unit (5); The rotation of the active flywheel (8) also drives the coaxial rotation of the driven flywheel (9) through the transmission gear (14), thereby achieving a secondary amplification of the flywheel inertia; Since the tuned vibration absorbing unit (6) is fixedly connected to the arc-shaped rack of the restoring unit (5), the restoring unit (5) generates a horizontal displacement relative to the centroid of the inertial unit (3). At this time, the arc-shaped rack drives the gear of the inertial unit (3) to rotate. While the inertial unit (3) rotates, its centroid is raised by the arc-shaped rack, compressing the output end of the damping unit (2). The two end points of the damping unit (2) generate relative displacement and relative velocity, thereby realizing nonlinear damping energy dissipation. The inertial unit (3) applies a normal pressure to the restoration unit (5) through the arc-shaped rack based on the unit's own weight. The horizontal component of the normal pressure causes the tuned vibration absorbing unit (6) to move horizontally. When the tuned vibration absorbing unit (6) moves back to the system equilibrium state from the horizontal maximum displacement position, the positive and negative stiffness intervals of the magnetic field are swapped, preferentially showing a negative stiffness characteristic that promotes the tuned vibration absorbing unit (6) to move back to the initial equilibrium position.

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