Steel trunk-branch bionic ultra-low frequency seismic hypersurface

Abstract

The application relates to the field of building earthquake resistance, and particularly relates to a steel trunk-branch bionic ultralow-frequency earthquake hypersurface. The steel trunk-branch bionic ultralow-frequency earthquake hypersurface comprises a tree-shaped resonator, a plurality of resonators enclosing a protected object in the center, the tree-shaped resonator comprises a steel trunk and steel branches, the steel trunk is vertically fixed on the surface of the ground, the steel branches comprise a plurality of stages of steel branches, wherein a steel first-order branch is fixedly connected with the top of the steel trunk, and the top of the steel branch is fixedly connected with the bottom of the lower-order steel branch in sequence. The steel trunk-branch bionic ultralow-frequency earthquake hypersurface is fixed on the ground around the protected object, when surface waves reach the array, a Rayleigh wave and other surface wave components are converted into deep body waves through wave mode conversion, and the structure earthquake resistance is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building earthquake resistance, and particularly relates to a steel trunk-branch bionic ultra-low frequency earthquake hypersurface. BACKGROUND

[0002] Earthquake is a sudden and destructive natural disaster, which causes serious harm to people's life safety and property safety. At present, the main way to resist such a huge natural disaster as earthquake is to set various anti-seismic structures in buildings. Although anti-seismic supports and shear walls and other anti-seismic measures have achieved certain anti-seismic effect, there are still problems of high cost and difficulty in protecting the existing buildings.

[0003] Seismic waves are divided into body waves and surface waves, among which Rayleigh waves as a kind of surface waves have the characteristics of long propagation distance and great destructive power, and are the main factor causing structural damage. The application of hypersurface to regulate and control seismic surface waves is a relatively innovative anti-seismic way, which can regulate Rayleigh waves through surface resonance, thereby mode-converting the surface waves and leading them into the deep crust, so as to protect buildings and cities from the influence of earthquakes. For the problem of ultra-low frequency band gap within 0-8Hz, the existing earthquake metamaterials still have the problems of high band gap position and high manufacturing cost, which leads to the difficulty of applying the hypersurface in actual engineering. SUMMARY

[0004] The purpose of the present application is to overcome the above-mentioned defects in the prior art, and to provide a steel trunk-branch bionic ultra-low frequency earthquake hypersurface for attenuating seismic surface waves below 8Hz. The hypersurface is fixed on the ground around the protected object. When the surface wave reaches the array, the Rayleigh wave component and other surface wave components are converted into deep body waves through wave mode conversion, so as to realize structural earthquake resistance.

[0005] The technical scheme of the present application is as follows: a steel trunk-branch bionic ultra-low frequency earthquake hypersurface, comprising

[0006] The tree-shaped resonator encloses the protected object in the center.

[0007] The tree-shaped resonator comprises a steel trunk and a steel branch. The steel trunk is vertically fixed on the ground surface. The steel branch comprises several stages of steel branches, wherein the first-order steel branch is fixedly connected to the top of the steel trunk, and the top of the steel branch is fixedly connected to the bottom of the lower-order steel branch in sequence.

[0008] In the present application, the tree-shaped resonator comprises a steel trunk and a first-order steel branch. The top of the steel trunk is fixed with several first-order steel branches, and the first-order steel branches are arranged obliquely between the steel trunk.

[0009] The steel trunk is a cuboid, the steel first-order branch is an inclined quadrangular prism, and the cross-sectional shape of the steel trunk and the steel first-order branch is a square.

[0010] The top of the steel first-order branch is fixed with a plurality of steel second-order branches, and the steel second-order branches and the steel first-order branch are arranged in an inclined manner.

[0011] The steel trunk is a cuboid, the steel first-order branch is an inclined quadrangular prism, and the cross-sectional shape of the steel trunk and the steel first-order branch is a square.

[0012] The steel second-order branch is an inclined triangular prism, and the cross-sectional shape of the steel second-order branch is an isosceles right triangle.

[0013] The material parameters of the steel trunk and the steel branch are: Young's modulus E st = 210 Gpa, Poisson's ratio mu st = 0.3, mass density rho st = 7850 kg / m 3 .

[0014] The beneficial effects of the present application are:

[0015] (1) The seismic super surface is composed of only one kind of steel material, and only needs to be assembled by bolts or welding when assembled, without involving the combination of steel and rubber and other materials, and without the need to bury the steel column or other artificial bodies underground, but is directly fixed on the ground around the protected building;

[0016] (2) The super surface can utilize the band gap characteristics to convert the Love wave with long propagation distance and very harmful into deep body wave, so that the building structure is protected from the earthquake;

[0017] (3) By changing the diameter of the steel trunk, the angle and number of the steel branch, the position of the band gap center frequency can be further reduced, and more band gaps can be opened, which can greatly reduce the Love wave energy of the surface around the building, and provide a new way for building seismic resistance and urban area seismic resistance.

[0018] In summary, the present application provides an ultra-low frequency seismic super surface for attenuating seismic surface waves below 8Hz, which is fixed on the ground around the protected object, and converts the Love wave and other surface wave components into deep body waves by wave mode conversion when the surface wave reaches the array. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a seismic protection schematic diagram in which the present application is arranged around the building;

[0020] Figure 2is a structural schematic diagram of arranging a steel trunk-branch bionic superlow-frequency seismic super surface for any protected building in Example 1;

[0021] Figure 3 is a structural schematic diagram of the application in Example 1;

[0022] Figure 4 is a band gap distribution of the application in Example 1;

[0023] Figure 5 is a steady-state frequency domain response of the application in Example 1;

[0024] Figure 6 is a steady-state surface wave mode conversion simulation result of the application in Example 1;

[0025] Figure 7 is a structural schematic diagram of the application in Example 2;

[0026] Figure 8 is a structural schematic diagram of arranging a steel trunk-branch bionic superlow-frequency seismic super surface for any specified protected area in Example 3.

[0027] In the figure: 1 Rayleigh wave; 2 tree resonator; 3 protected building; 4 protected area; 5 steel trunk; 6 steel branch I; 7 steel branch II; 8 steel branch III; 9 steel branch IV; 10 steel first-order branch; 11 steel second-order branch. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0029] In the following description, specific details are set forth in order to provide a thorough understanding of the application. However, the application can be practiced without the specific details, other than in the examples, and it will be apparent to those skilled in the art that the application can be practiced without departing from the scope of the application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0030] Example 1

[0031] The steel trunk-branch bionic superlow-frequency seismic super surface comprises a plurality of tree resonators, which are distributed around the protected building in space according to a certain period and enclose the protected building in the center.

[0032] As Figure 1 and Figure 2As shown, the steel trunk-branch bionic super-low frequency seismic super surface in the embodiment includes a plurality of tree-shaped resonators 2 arranged in a square lattice period, and the tree-shaped resonators 2 are vertically fixed on the ground surface around the protected building 3 to form a seismic super surface. The seismic super surface generally surrounds the protected building 3 and encloses the protected building 3 to achieve seismic protection of the protected building. When Rayleigh wave 1 in any direction reaches the seismic super surface, the Rayleigh wave 1 is converted into body wave in the deep crust by the super surface structure, thereby achieving structural seismic resistance.

[0033] As shown in the figure, Figure 3 The tree-shaped resonator includes a steel trunk 5 arranged vertically to the ground surface, and four steel branches, namely steel branch I 6, steel branch II 7, steel branch III 8 and steel branch IV 9, fixed to the top of the steel trunk 5. In the embodiment, the steel trunk 5 is a rectangular prism with a size of 1.5 m*1.5 m*15 m, and the bottom end of the steel trunk 5 is fixed vertically to the ground. The steel branch is an inclined quadrilateral prism with a size of 0.5 m*0.5 m*10 m, and is arranged obliquely between the steel trunk 5 and the steel branch. The bottom end of the four steel branches is fixedly connected to the top center of the steel trunk, which can be fixedly connected by welding or bolt. By adjusting the length of the steel trunk and the steel branch, and the inclination angle between the steel trunk and the steel branch, the band gap position and the band gap width can be adjusted.

[0034] The steel used is ordinary Q235 steel or other building steel, and the material parameters of the steel are as follows: Young's modulus E st = 210 Gpa, Poisson's ratio μ st = 0.3, mass density ρ st = 7850 kg / m 3 .

[0035] The tree-shaped resonator is fixed to the ground, and the contact surface of the resonator and the ground is flanked by two materials with extremely large impedance ratios. At this time, the materials on both sides of the contact surface can form impedance matching, so that the tree-shaped resonator can convert the surface wave in the band gap range into body wave in the deep crust through the impedance matching mechanism, thereby achieving seismic resistance of the protected building.

[0036] As shown in the figure, Figure 4 The band gap distribution of the steel branch-trunk super-low frequency seismic super surface in the embodiment is shown in the figure. According to the figure, the steel branch-trunk super-low frequency seismic super surface in the embodiment has four low frequency band gaps, namely 0 Hz-0.5 Hz, 3.7 Hz-4 Hz, 4.1 Hz-5.6 Hz and 6.8 Hz-8.0 Hz, and the four band gaps are all below 8 Hz,

[0037] As shown in the figure, Figure 5The figure shows the steady-state frequency domain response of the steel tree branch-trunk ultra-low frequency seismic metasurface in this embodiment. It has four obvious transmission valleys in 0Hz-0.5Hz, 3.7Hz-4Hz, 4.1Hz-5.6Hz, and 6.8Hz-8.0Hz, indicating that surface waves are significantly suppressed in these frequency ranges.

[0038] like Figure 6 The figure shows the steady-state response of the 5Hz elastic wave. It can be seen that the 5Hz ultra-low frequency surface wave changed its original propagation direction under the action of the steel tree branch-trunk ultra-low frequency seismic metasurface and was converted into a deep body wave.

[0039] Example 2

[0040] like Figure 7 As shown, in this embodiment, the order of the steel branches in the tree resonator can be further increased, that is, further branching can be made on the steel branches in Embodiment 1.

[0041] The tree-shaped resonator in this embodiment includes a steel trunk 5, first-order steel branches 10, and second-order steel branches 11. The bottom of the steel trunk 5 is vertically fixed to the ground surface, and several first-order steel branches 10 are fixed to the top of the steel trunk 5, with the first-order steel branches 10 inclined to the steel trunk 5. The bottom of the first-order steel branches 10 is fixedly connected to the top of the steel trunk 5 by welding or bolts. Several second-order steel branches 11 are fixed to the top of the first-order steel branches 10, with the second-order steel branches 11 inclined to the first-order steel branches 10.

[0042] The steel trunk 5 is a cuboid measuring 1.5m x 1.5m x 15m, with its base vertically fixed to the ground. The first-order steel branch 10 is a 0.5m x 0.5m x 10m oblique quadrangular prism, and the second-order steel branch 11 is an oblique triangular prism with a cross-section of a 0.5m x 0.5m isosceles right triangle. By adjusting the lengths of the steel trunk, first-order steel branches, and second-order steel branches, as well as the angles between the steel trunk and first-order steel branches, and between the first-order and second-order steel branches, the bandgap position and width can be adjusted. Furthermore, by adjusting the height and angle of the second-order steel branches, resonance at other frequencies can be induced, opening up more localized resonant bandgaps.

[0043] Everything else is the same as in Example 1.

[0044] Example 3

[0045] like Figure 8 As shown, the tree-shaped resonators 2 are spatially distributed and arranged periodically around the protected area 4, with the tree-shaped resonators 2 enclosing the protected area 4 at its center. The protected area 4 can be a designated area of ​​any size.

[0046] The tree resonator 2 in the embodiment 1 can adopt the tree resonator in the standard form of the embodiment 1 or the tree resonator in the extended form of the embodiment 2.

[0047] The other is the same as the embodiment 1.

[0048] The steel stem-branch bionic ultralow-frequency seismic hypersurface provided by the present application is described in detail above. The principles and implementation manners of the present application are described by using specific examples in this paper, and the above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application. The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications of these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A steel trunk-branch biomimetic ultra-low frequency seismic metasurface, characterized in that, Comprising The tree resonator encloses the protected object in the center; The tree resonator includes a steel trunk and a steel branch, the steel trunk is fixed vertically on the ground surface, the steel branch includes several levels of steel branches, wherein the steel first-order branch is fixedly connected with the top of the steel trunk, the top of the steel branch is fixedly connected with the bottom of the lower-order steel branch in turn, and the steel trunk and the steel branch are arranged in an inclined manner; The length of the steel trunk and the steel branch, and the inclination angle between the steel trunk and the steel branch are adjusted to adjust the band gap position and the band gap width.

2. The steel trunk-branch bionic ultra-low frequency seismic hypersurface according to claim 1, wherein The tree resonator includes a steel trunk and a steel first-order branch, the top of the steel trunk is fixed with a plurality of steel first-order branches, and the steel first-order branch and the steel trunk are arranged in an inclined manner.

3. The steel trunk-branch bionic ultra-low frequency seismic hypersurface according to claim 1, wherein The tree resonator includes a steel trunk, a steel first-order branch and a steel second-order branch, the top of the steel trunk is fixed with a plurality of steel first-order branches, and the steel first-order branch and the steel trunk are arranged in an inclined manner; The top of the steel first-order branch is fixed with a plurality of steel second-order branches, and the steel second-order branch and the steel first-order branch are arranged in an inclined manner.

4. The steel trunk-branch bionic ultra-low frequency seismic hypersurface according to claim 2 or 3, wherein The steel trunk is a rectangular solid, the steel first-order branch is a slanting quadrangular prism, and the cross sections of the steel trunk and the steel first-order branch are both square.

5. The steel trunk-branch bionic ultra-low frequency seismic hypersurface according to claim 3, wherein The steel second-order branch is a slanting triangular prism, and the cross section of the steel second-order branch is an isosceles right triangle.

6. The steel trunk-branch bionic ultra-low frequency seismic hypersurface according to claim 1, wherein The material parameters of the steel trunk and steel branches are: Young's modulus E st = 210 GPa, Poisson's ratio μ st = 0.3, mass density ρ st = 7850 kg / m 3 .

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