Anti-wind-vibration device and method for ancient famous wood based on particle damping

Abstract

The invention discloses an ancient-name wood wind vibration resistance device and method based on particle damping, the ancient-name wood wind vibration resistance device comprises a plurality of unit-cell particle damping shock absorbers which are periodically arranged and connected, each unit-cell particle damping shock absorber comprises a box body, a damping interlayer is laid on the inner wall of each box body, and the box bodies are filled with damping particles. The device is fixed to the position of a branch or a crotch of a tall famous tree through binding belts, binding rings, nailing and the like to achieve the wind vibration resisting effect. The device can be fixed on the surface of a tree or any other object, so that the device is convenient to mount and wide in applicability; a proper amount of damping particles can be added according to the vibration frequency of the tree, so that the advantages of wide vibration reduction frequency band, high reliability, low cost and the like can be realized.

Description

Technical Field

[0001] The present invention relates to the technical fields of gardening and vibration reduction, and in particular to a device and method for resisting wind vibration of ancient famous trees based on particle damping. Background Art

[0002] Typhoon-induced strong winds can knock down trees, damage houses, and harm infrastructure. Every year, strong winds in southern China frequently cause tree downfalls. Urban gardens often use wood or steel to support tree trunks. However, tall, valuable trees are generally less resistant to wind vibration. Due to their limited support, these bracing systems are unable to withstand strong winds. However, little research has been conducted on wind-resistant vibration design for these valuable trees.

[0003] Particle damping (PD) is a passive vibration reduction technology that fills the cavity of a vibrating structure with tiny particles (such as steel balls, ceramics, and glass beads). The technology utilizes friction and inelastic collisions between the particles and between the particles and the cavity walls to dissipate the system's vibration energy, thereby suppressing structural vibration. Particle damping technology offers advantages such as minimal impact on structural stiffness, low added mass, suitability for harsh environments such as high temperature and corrosion, and stable vibration reduction performance over time. The vibration reduction mechanism of particle damping involves complex nonlinear dynamic behavior between particles and between particles and the wall, including collisions and friction. The energy dissipation process is influenced by factors such as particle filling fraction, particle size, material properties, external excitation frequency, and acceleration. Models such as the discrete element method (DEM) are often used for simulation and analysis to study the vibration reduction effect of particle damping.

[0004] Traditional tuned mass dampers (TMDs) utilize system resonance to absorb vibration energy and reduce vibration in equipment or foundations. Because their structural parameters cannot be changed and their natural frequency cannot be adjusted, traditional dynamic vibration absorbers can only reduce vibration at a single frequency, resulting in a narrow frequency adjustment range and limited vibration reduction effectiveness. In reality, wind loads are complex, and tree vibrations are not fixed and have complex and variable frequencies. Therefore, a single damper cannot effectively mitigate wind vibrations. Summary of the Invention

[0005] The purpose of the present invention is to provide a device for resisting wind vibration of ancient famous trees based on particle damping, which solves the technical problem of insufficient wind vibration resistance of trees.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a particle damping-based device for resisting wind vibrations of ancient and famous trees, comprising a plurality of periodically arranged and connected single-cell particle dampers. Each particle damper comprises a box, the inner wall of which is paved with a damping interlayer and filled with damping particles. The device is secured to the branches or forks of a tall and famous tree using straps, lashing rings, or nails to achieve wind vibration resistance.

[0007] Preferably, the side of the damping interlayer facing the damping particles is provided with array-arranged protrusions.

[0008] Preferably, the convex points are one of hemispherical convex points, polygonal pyramid convex points, polygonal prism convex points, and cylindrical convex points.

[0009] Preferably, the damping particles are spherical particles. The damping particles dissipate energy through friction with each other, nonlinear deformation at contact points between the damping particles, and resonance of the damping particle material.

[0010] Preferably, the damping particles include a convex base and a concave elastic body wrapped around the convex base, which is beneficial for increasing the attachment area between the convex base and the concave elastic body, making it easier to consolidate into a whole, and also helping the concave elastic body to exert better damping properties.

[0011] Preferably, the convex base is made of a hard material, and the concave elastic body is made of an elastic material. The collision between the hard convex base and the concave elastic body, which contain different damping particles, can better dissipate energy (absorb vibration energy) during the compression of the elastic material, compared to the collision between hard particles alone, thereby achieving a better vibration reduction effect.

[0012] Preferably, the hard material is one or more of hard alloy, hard plastic, ceramic, iron, and tempered glass; and the elastic material is one or more of rubber, styrene, polyurethane, polyolefin, and polyamide.

[0013] Preferably, the convex base includes a sphere, and cylinders are provided in six directions of the sphere; the concave elastic body is a hollow structure, and the shape of the hollow structure matches the convex base.

[0014] Preferably, an upper cover is provided on one side of the box body, and a damping interlayer is laid on the inner wall of the upper cover.

[0015] Preferably, the cross section of the box body is rectangular or fan-shaped.

[0016] A particle damping-based method for resisting wind vibration of ancient trees involves installing single-cell particle damping vibration isolators on the surface of trees or any other objects that need to resist wind vibration. The appropriate damping particle matrix and elastomer material, damping particle filling rate, and periodic combination of the damping vibration isolators are selected according to wind load and vibration frequency.

[0017] Compared with the prior art, the present invention has the following beneficial effects: Because the present invention can be fixed to trees or any other surface requiring wind vibration resistance, it is easy to install and has wide applicability. The damping particle matrix and elastomer material, the damping particle filling ratio, and the periodic combination of the damping absorber can be selected based on the tree's vibration frequency under different wind loads. Due to the nonlinearity of the damping material, the nonlinearity of the collision, and the bandgap characteristics of the periodic structure, broadband vibration reduction can be achieved with high reliability. The damping absorber is manufactured using inexpensive materials and a simple process, resulting in low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention (1 / 4 cross-sectional view); Figure 2 Schematic diagram of the single-cell particle damping vibration absorber of the present invention (1 / 4 cross-sectional view); Figure 3 This is a schematic structural diagram of a convex base according to an embodiment of the present invention; Figure 4 This is a schematic structural diagram of a concave elastic body according to an embodiment of the present invention (1 / 4 cross-sectional view); Figure 5 This is a schematic cross-sectional structure diagram of a box body and a damping interlayer according to an embodiment of the present invention; Figure 6 Schematic diagram of the cross-sectional structure of another box body and damping interlayer according to an embodiment of the present invention; Figure 7 Schematic diagram of the structure of the damping interlayer according to an embodiment of the present invention; Figure 8 for Figure 7 AA cross-sectional structural diagram; Figure 9 is a schematic diagram of damping particle momentum; Figure 10 Schematic diagram comparing the vibration reduction effects before and after installation of the present invention.

[0019] In the figure: 1, single-cell particle damping vibration isolator, 2, upper cover, 3, box body, 4, damping particles, 5, damping interlayer, 41, convex base, 42, concave elastic body, 411, sphere, 412, cylinder. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] See also Figure 1-Figure 2A wind-vibration-resistant device for ancient famous trees based on particle damping includes a plurality of periodically arranged and connected single-cell particle damping vibration absorbers 1. The single-cell particle damping vibration absorber 1 includes a box body 3, the inner wall of the box body 3 is fixedly paved with a damping interlayer 5, and the box body 3 is filled with damping particles 4.

[0022] By setting multiple layers, multiple rows, and multiple columns, such as Figure 1 In the 3*3*3 structure, multiple single-cell particle dampers 1 form a periodic particle damper, which utilizes the band gap to prevent the propagation of wind vibrations within it. The periodic particle damper can be secured to the branches or forks of tall, prestigious trees using straps, lashing rings, or nails to mitigate wind vibrations. It can also be used on other objects requiring wind and vibration protection.

[0023] like Figure 3-Figure 4 As shown, the damping particles 4 are spherical particles. The damping particles 4 include a convex base 41 and a concave elastomer 42 wrapped around the convex base 41. The convex base 41 is made of a hard material, which is one or more of hard alloy, hard plastic, ceramic, iron, and tempered glass. The concave elastomer 42 is made of an elastic material, which is one or more of rubber, styrene, polyurethane, polyolefin, and polyamide. Compared with the collision between simple hard particles, the collision between the hard convex bases of different damping particles and the concave elastomer can better dissipate energy (absorb vibration energy) during the extrusion of the elastic material, thereby achieving a better vibration reduction effect.

[0024] In a specific embodiment, the convex base 41 comprises a sphere 411, with cylindrical bodies 412 positioned in six directions around the sphere 411; the spheres 411 and cylindrical bodies 412 form an integral structure. The concave elastic body 42 is hollow, its shape matching that of the convex base 41. The convex base 41 is positioned within the concave elastic body 42 by bonding, vulcanization, or other methods. This design increases the attachment area between the convex base and the concave elastic body, facilitating their integration and enhancing the damping properties of the concave elastic body.

[0025] like Figure 5-Figure 8 As shown, the box body 3 is provided with an upper cover 2 on one side, and the inner wall of the upper cover 2 is provided with a damping interlayer 5. The shape of the box body can be adjusted according to the shape of the restrained object. The cross-section of the box body 3 can be designed to be rectangular or fan-shaped, so that it fits the restrained object better and achieves better wind resistance and vibration reduction. When the cross-section of the box body 3 is fan-shaped, multiple single-cell particle dampers can be connected end to end to form a ring structure, which can be installed on cylindrical objects such as tree trunks or branches.

[0026] The damping interlayer 5 has an array of raised bumps on one side facing the damping particles 4 and a flat surface on the other side. The damping interlayer 5 is secured to the inner walls of the upper cover 2 and the box body 3 by adhesive bonding or other means. The raised bumps can be hemispherical, pyramidal, prismatic, or cylindrical. The damping interlayer 5 can be made of modified polyurethane urea, sponge, plastic, rubber, polyurethane, or other materials.

[0027] A particle damping-based method for resisting wind vibration of ancient trees involves installing single-cell particle damping vibration isolators on the surface of trees or any other objects that need to resist wind vibration. The appropriate damping particle matrix and elastomer material, damping particle filling rate, and periodic combination of the damping vibration isolators are selected according to wind load and vibration frequency.

[0028] Under wind loads, the present invention can block vibrations of a certain frequency through band gaps. Damping particles 4 collide with each other, or with the damping interlayer 5. During the collision, energy is dissipated through impact, and the viscoelastic damping material converts vibration kinetic energy into heat by squeezing the concave elastomer 42 and the damping interlayer 5. Particles dissipate energy through friction, nonlinear deformation at contact points, and resonance of the granular material. The collision of damping particles also exhibits nonlinear characteristics, resulting in a vibration-damping effect and a wide frequency bandwidth.

[0029] In multibody dynamics and discrete element methods, damping particles dissipate energy in the form of friction and collision. This example uses the Hertz-Mindlin soft-sphere model to calculate the normal and tangential contact of damping particles during collision. Normal motion is simplified to a spring-damper element, while tangential motion is simplified to the combined force of the spring damper and sliding friction.

[0030] Damping the collision force between particles : (1); Where, Damping particles and damping particles The force of collision between is the normal stiffness between the damping particles; is the relative displacement between damping particles; is the relative velocity between damping particles; is the damping coefficient between damping particles. For particles quality, For particles quality.

[0031] Similarly, the collision force between the damping particles and the damping interlayer can be obtained: (2); Where, Damping particles The force of collision between the damping interlayer and the damping interlayer; is the stiffness between the damping particles and the damping interlayer; is the displacement of the damping particle; is the velocity of the damping particle; is the damping coefficient between the damping particles and the damping interlayer.

[0032] Based on the forces between the damping particles and between the damping particles and the damping interlayer, Newton's laws of motion are used to calculate the velocities of the damping particles before and after the collision. Relative velocities are divided into normal and tangential cases.

[0033] (3); Where, is the normal velocity of the damping particle, is the tangential velocity of the damping particles; 、 Damping particles , angular velocity; , Damping particles , radius.

[0034] Therefore, the inelastic collision energy dissipation between damping particles can be obtained as: (4); Where, To damp the energy dissipated by inelastic collisions between particles; is the restitution coefficient of the surface material of the damping particles; is the relative velocity of the two damping particles before collision.

[0035] The energy consumption of damping particles is mainly composed of collision and friction. The friction energy consumption between any two damping particles is: (5); Where, To damp the friction energy between particles, is the friction coefficient between the damping particles; is the relative displacement between the damping particles in the tangential direction.

[0036] The total energy consumption of damping particles is: (6); Where, is the total energy consumption of the damping particles; To damp the energy dissipated by inelastic collisions between particles; is the friction energy dissipated between the two damping particles.

[0037] like Figure 9 As shown in the figure, by establishing a coupled multi-body dynamics and discrete element model, the vibration reduction effect of the periodic particle damping shock absorber is calculated and analyzed. Figure 10 As shown, it can be found that the wind vibration reduction rate of the tall and famous wood with periodic particle damping vibration isolators installed is more than 70%, and it can basically achieve vibration reduction effects in all frequency bands.

Claims

1. A wind-vibration-resistant device for ancient famous trees based on particle damping, characterized in that: The invention comprises a plurality of periodically arranged and connected single-cell particle damping vibration absorbers (1), wherein the single-cell particle damping vibration absorber (1) comprises a box body (3), the inner wall of the box body (3) is paved with a damping interlayer (5), and the box body (3) is filled with damping particles (4).

2. The device for resisting wind vibration of ancient famous trees based on particle damping according to claim 1 is characterized in that: The side of the damping interlayer (5) facing the damping particles (4) is provided with array-arranged convex points.

3. The device for resisting wind vibration of ancient famous trees based on particle damping according to claim 2 is characterized in that: The convex points are one of hemispherical convex points, polygonal pyramid convex points, polygonal column convex points and cylindrical convex points.

4. The device for resisting wind vibration of ancient famous trees based on particle damping according to claim 1 is characterized in that: The damping particles (4) are spherical particles.

5. The device for resisting wind vibration of ancient famous trees based on particle damping according to claim 4 is characterized in that: The damping particles (4) include a convex base (41) and a concave elastic body (42) wrapped around the convex base (41).

6. The device for resisting wind vibration of ancient famous trees based on particle damping according to claim 5 is characterized in that: The convex base (41) is made of a hard material, and the concave elastic body (42) is made of an elastic material.

7. The device for resisting wind vibration of ancient famous trees based on particle damping according to claim 6 is characterized in that: The hard material is one or more of hard alloy, hard plastic, ceramic, iron, and tempered glass; the elastic material is one or more of rubber, styrene, polyurethane, polyolefin, and polyamide.

8. The device for resisting wind vibration of ancient famous trees based on particle damping according to claim 5 is characterized in that: The convex base (41) includes a sphere (411), and cylinders (412) are provided in six directions of the sphere (411); the concave elastic body (42) is a hollow structure, and the shape of the hollow structure matches the convex base (41).

9. The device for resisting wind vibration of ancient famous trees based on particle damping according to claim 1 is characterized in that: An upper cover (2) is provided on one side of the box body (3), and a damping interlayer (5) is laid on the inner wall of the upper cover (2).

10. The ancient famous wood wind-vibration resistance device based on particle damping according to claim 1 is characterized in that: The cross section of the box body (3) is rectangular or fan-shaped.

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