A method of coding reconfigurable topology phononic crystal waveguide

Abstract

The application discloses a kind of encoding reconfigurable topology phononic crystal waveguide methods, adopt neodymium iron boron base structure design reconfigurable topology phononic crystal structure form;Based on reconfigurable topology phononic crystal structure form, the supercell dispersion curve of in situ scatterer is calculated, obtains K point feature;Adjust the angle of scatterer α, calculate corresponding cell dispersion curve and obtain K point feature, obtain corresponding topology Chen number C K Phononic crystal;Two kinds of phononic crystal supercells obtained by encoding combination construct strip-shaped phononic crystal, calculate dispersion curve and obtain edge state characteristics, obtain edge state band, realize encoding reconfigurable phononic crystal waveguide method.The application is easy to operate, and can realize the directional regulation and control of propagation path under surface wave waveguide.

Description

Technical Field

[0001] This invention belongs to the field of phononic crystal technology, specifically relating to a coded reconfigurable topological phononic crystal waveguide method. Background Technology

[0002] With the development of phononic crystals in the field of acoustic waveguide technology, it has become increasingly important to achieve highly robust transmission of sound waves and precise control of the transmission path. Phononic crystal waveguides are divided into bulk wave type and surface wave type, corresponding to bulk waves and surface waves respectively. Due to the strong coupling relationship and the complexity of waves, existing surface wave phononic crystals are not reconfigurable and waveguide setup is difficult. Therefore, reconfigurable surface wave phononic crystals have great application prospects in the field of acoustic waveguides.

[0003] Surface acoustic wave phononic crystal waveguides are classified into bandgap and topological methods based on their principles. Compared to the bandgap method, topological phononic crystals, which are widely used in surface acoustic wave waveguides, have advantages such as low loss, high robustness, and strong controllability, making them more suitable for controlling acoustic wave transmission and transmission path manipulation. Topological phononic crystal technology considers introducing multiple wave modes into elastic wave systems, mainly manifested in the construction of pseudospin at the K-point (Dirac point). The specific approach is to adjust the geometric characteristics of the phononic crystal supercell designed by topological adjustment. Based on breaking the time reversal symmetry of the hexagonal lattice structure supercell, the pseudospin multipole mode inversion of surface acoustic waves is induced (e.g., by changing the angle of the scatterer in the supercell). Topological boundary states coupled with topological trivial and nontrivial states and pseudospin orbitals are constructed, thereby designing topological phononic crystal waveguides with various transmission paths.

[0004] Although surface wave topological phononic crystal waveguide technology can achieve precise control of surface waves and has advantages such as simple structure, some problems still exist. For surface wave systems, unlike bulk wave systems, the waveguide and the wave propagation substrate need an external coupling means to achieve successful coupling (bulk waves can couple on their own using air or water). For example, using strong coupling agents (adhesives) for connection and fixation will first introduce undesirable strong coupling agent materials, increasing the design error of the phononic crystal supercell and affecting the transmission performance of the phononic crystal waveguide. Secondly, the introduction of strong coupling agents is not conducive to the topological adjustment of the phononic crystal supercell. This strong coupling relationship needs to be removed before the supercell topological adjustment can be performed, and the coupling means need to be reused for connection and fixation. This reduces the convenience of adjustment, setup and use of the topological phononic crystal waveguide and increases the implementation difficulty. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a coded reconfigurable topological phononic crystal waveguide method based on the magnetic attraction of a neodymium iron boron substrate. This method is used to solve the technical problems that the introduction of strong coupling agent materials causes large structural errors and affects the transmission performance of phononic crystal waveguides, as well as the inconvenience and difficulty in adjusting phononic crystal waveguides under strong coupling relationships.

[0006] The present invention adopts the following technical solution:

[0007] A coded reconfigurable topological phononic crystal waveguide method includes the following steps:

[0008] S1. A reconfigurable topological phononic crystal structure is designed using a neodymium iron boron substrate structure.

[0009] S2. Based on the reconfigurable topological phononic crystal structure obtained in step S1, calculate the supercell dispersion curve of the in-situ scatterer and obtain the K-point feature.

[0010] S3. Adjust the scatterer angle α, calculate the corresponding cell dispersion curve and obtain the K-point feature, then obtain the corresponding topological Chern number C. K Phononic crystals;

[0011] S4. Construct a strip phononic crystal by combining the two phononic crystal supercells obtained in step S3, calculate the dispersion curve and obtain the edge state characteristics, obtain the edge state frequency band, and realize the coded reconfigurable phononic crystal waveguide method.

[0012] Specifically, in step S1, the reconfigurable topological phononic crystal structure is composed of several phononic crystal supercells, each of which is a top-bottom symmetrical structure.

[0013] Furthermore, the NdFeB substrate is symmetrically distributed on the upper and lower surfaces of the aluminum plate. By adjusting the angle of the carbon steel scatterer on the NdFeB substrate, the pseudospin mode of the surface wave can be controlled. This is achieved by adjusting the topological Chern number C of each supercell. K Construct topological edge states.

[0014] Furthermore, the angle of the corresponding scatterer can be adjusted mechanically.

[0015] Furthermore, the NdFeB substrate has a circular structure.

[0016] Specifically, in step S1, the material parameters of the reconfigurable topological phonon crystal structure include: the density, Young's modulus, and Poisson's ratio of the scatterer carbon steel are 7890 kg / m³. 3 209 GPa, 0.269, NdFeB substrate density, Young's modulus, and Poisson's ratio are 7500 kg / m³. 3160 GPa, 0.24, density, Young's modulus, and Poisson's ratio of 6061 aluminum plate are 2700 kg / m³. 3 70 GPa, 0.33; Structural parameters include: a = 25 mm, R = 12 mm, s = 11 mm, w = 4 mm, α = 0°, l = 10 mm, t = 0.5 mm, h = 4 mm.

[0017] Specifically, in step S2, the finite element model and Floquet periodic boundary are set in the COMSOL simulation software, and the dispersion curve of the in-situ scattering supercell is calculated along the first simplest Brillouin zone wave vector direction of the lattice.

[0018] Specifically, in step S3, the finite element model and Floquet periodic boundary are set in the COMSOL simulation software, and the dispersion curve of the supercell is calculated along the wave vector direction of the first simplest Brillouin zone of the lattice.

[0019] Furthermore, the scatterer angle α = -30° or α = 30°.

[0020] Specifically, in step S4, the finite element model and Floquet periodic boundary are set in the COMSOL simulation software, and the dispersion curve of the strip phononic crystal is calculated along the horizontal wave vector direction to obtain the edge state characteristics and obtain the edge state frequency band.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] A coded reconfigurable topological phononic crystal waveguide method is proposed, which achieves the purpose of coded reconfigurable topological waveguide transmission by reconfiguring the angle of the supercell scatterer to change its topological boundary state.

[0023] Furthermore, the top-bottom symmetric structure of the supercell is beneficial for enhancing the Bragg scattering effect and improving waveguide transmission stability.

[0024] Furthermore, by abandoning the traditional adhesive coupling method, the reconfigurable adjustment of the carbon steel scatterer angle greatly improves the convenience and reusability of waveguide adjustment.

[0025] Furthermore, mechanical adjustment of the corresponding scatterer angle makes waveguide adjustment simpler and more convenient.

[0026] Furthermore, the circular structure of the NdFeB substrate facilitates processing and shaping.

[0027] Furthermore, the material and structural parameters of each part in the reconfigurable topological phononic crystal structure are set for finite element calculation to obtain the corresponding properties.

[0028] Furthermore, the dispersion curve of the in-situ scatterer supercell is calculated to observe its time reversal symmetry and Dirac point, which serve as a reference benchmark for subsequent supercells.

[0029] Furthermore, the dispersion curves of the supercells were calculated to observe their time-reversal symmetry and Dirac points, and the frequency range of the Dirac breakpoints and the topological Chern number C were observed. K .

[0030] Furthermore, the Dirac point is opened to the greatest extent when the scatterer angle α = -30° or α = 30°, and the time reversal symmetry is most significantly broken.

[0031] Furthermore, calculating the dispersion curve of the strip phononic crystal and obtaining the edge state characteristics can verify the feasibility of waveguide transmission in advance, as the edge state frequency band is related to the frequency range of waveguide transmission.

[0032] In summary, the present invention is easy to operate and can achieve directional control of the propagation path under surface wave waveguides.

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0034] Figure 1 This diagram illustrates the implementation steps of the topological phononic crystal waveguide of the present invention.

[0035] Figure 2 The diagram shows a supercell of a topological phononic crystal, where (a) is a top view and (b) is a three-dimensional view.

[0036] Figure 3 This is a dispersion curve of a supercell (α = 0°) of an in-situ scatterer in a topological phononic crystal;

[0037] Figure 4 The graphs are supercell dispersion curves of a rotating scatterer in a topological phononic crystal, where (a) is α = -30° and (b) is α = 30°.

[0038] Figure 5 This is a schematic diagram of a topological boundary state banded phononic crystal, where (a) is the structure diagram and (b) is the dispersion curve diagram;

[0039] Figure 6 This is a schematic diagram of linear and polygonal waveguides for coded combinations;

[0040] Figure 7 These are schematic diagrams of surface wave propagation corresponding to straight and broken waveguides;

[0041] Figure 8 This is a schematic diagram of a complex piecewise linear waveguide with coded combinations;

[0042] Figure 9This is a schematic diagram of surface wave propagation corresponding to a complex polygonal waveguide;

[0043] Figure 10 This is a schematic diagram of a complex hexagonal waveguide with coded combination, where (a) is of type 0-1 and (b) is of type 1-0.

[0044] Figure 11 This is a schematic diagram of surface wave transmission corresponding to a complex hexagonal waveguide, where (a) is type 0-1 and (b) is type 1-0. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0047] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0049] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0050] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0051] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0052] This invention provides a coded reconfigurable topological phononic crystal based on the magnetic attraction of a NdFeB substrate. The surface waveguide is composed of several phononic crystal supercells, each of which has a vertically symmetrical structure and its scatterer angle can be mechanically adjusted. A circular NdFeB substrate symmetrically distributed on the upper and lower surfaces of an aluminum plate provides magnetic attraction to achieve coupling. Adjusting the angle of the carbon steel scatterer on the NdFeB substrate can control the pseudospin mode of the surface wave. By adjusting the pseudospin mode of each supercell, topological edge states are constructed, thereby realizing the setting of the corresponding waveguide structure and the control of acoustic wave transmission and transmission path. Through the reconfigurable supercell topological adjustment based on the magnetic attraction of the NdFeB substrate, various waveguide structures can be independently changed, achieving the setting and conversion of the "decoupling" topological phononic crystal waveguide.

[0053] Please see Figure 1 The present invention discloses a method for implementing a coded reconfigurable topological phonon crystal based on the magnetic attraction of a neodymium iron boron substrate, comprising the following steps:

[0054] S1. Design the reconfigurable topological phononic crystal structure, determine the material and structural parameters of each part, and introduce a neodymium iron boron substrate structure to provide the possibility for the realization of coded reconfigurable topological phononic crystal waveguides.

[0055] S2. Calculate the dispersion curve of the cell (α=0°) of the in-situ scatterer to obtain the K-point characteristics, which provides a basis for constructing the coded topological phonon crystal cell;

[0056] S3. Adjust the scatterer angle (change α), calculate the dispersion curves of the corresponding cells (α = -30° and α = 30°), obtain the K-point characteristics, obtain the corresponding pseudospin modes, and provide a basis for constructing edge states;

[0057] S4. Construct a strip phononic crystal using the two phononic crystal cells (denoted as "0" and "1") obtained by encoding and combining step S3, calculate the dispersion curve and obtain the edge state characteristics, obtain the edge state frequency band, and provide an encoded reconfigurable phononic crystal waveguide method.

[0058] S5. By combining phononic crystal cells with coding, straight and broken waveguides are set up to verify the transmission robustness and stability of simple waveguides, providing a foundation for the realization of complex waveguides.

[0059] S6. By encoding and combining phononic crystal cells to set up various complex waveguides, the transmission robustness and stability of complex waveguides are further verified, realizing the directional and highly robust transmission of surface waves.

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0061] In this embodiment, the dimensions of the aluminum plate, the two circular NdFeB magnetic substrates, and the two carbon steel scatterers are a = 25 mm, R = 12 mm, s = 11 mm, w = 4 mm, α = 0°, l = 10 mm, t = 0.5 mm, and h = 4 mm. α is variable. Figure 2 As shown.

[0062] The dispersion curves of phononic crystal cells (α = 0°, α = -30°, and α = 30°) were calculated using COMSOL. When α = 0°, the cell exhibits time-reversal symmetry, the Dirac point is not destroyed, and the Dirac point frequency is 15.9 kHz. Figure 3 As shown;

[0063] When α = -30°, the cellular time-reversal symmetry is broken, the Dirac point is destroyed, and the band gap at the Dirac break point ranges from 12.9 to 20.5 kHz. The valley Chern number of this topological phononic crystal is C. K =0.5,C K’ = -0.5; when α = -30°, similarly, the band gap at the Dirac break point ranges from 12.9 to 20.5 kHz, and the valley Chern number of this topological phononic crystal is C. K =-0.5, C K’ =0.5, such as Figure 4 As shown.

[0064] The combination of '0' and '1' to construct a strip phononic crystal has the following dispersion curve: Figure 5 As shown, the color gradient represents the normalized out-of-plane displacement, the edge state frequency range is 8–16 kHz, and the contrast-selective excitation frequency is 13.9 kHz. The encoded combined phonon crystal cell is configured with linear and piecewise waveguides as follows: Figure 6 As shown, the corresponding simple waveguide transmission at an operating frequency of 13.9kHz is as follows: Figure 7 As shown, the color gradient represents the normalized out-of-plane displacement, indicating that the waveguide transmission is stable and robust.

[0065] In the simulation process, complex waveguides are set up as the research object in the coding, such as... Figure 8 As shown, the control region is set as the encoding region, and the remaining regions are fixed. Only the scatterer of the unit cell to be encoded is rotated to encode the combination of '0' and '1' phonon crystal cells. Two Z-shaped and one bifurcated waveguides are shown in the diagram. The corresponding complex waveguide transmission at the operating frequency of 13.9 kHz is as follows. Figure 9 As shown, the color gradient represents the normalized out-of-plane displacement. The surface waves of the three waveguide transmissions are consistent with the set path, which shows that the waveguide transmission is stable and robust.

[0066] The coding scheme uses a hexagonal complex waveguide as the research object, such as... Figure 10 As shown, by simply rotating the scatterer of the unit cell to be encoded, the encoding combinations of '0' and '1' phonon crystal cells are used to set up the two types of hexagonal complex waveguides illustrated. The corresponding complex waveguide transmission at an operating frequency of 13.9 kHz is as follows. Figure 11 As shown, the color gradient represents the normalized out-of-plane displacement. The surface waves of both waveguide transmissions are consistent with the set path, indicating that the waveguide transmission is stable and robust.

[0067] In summary, the present invention provides an coded reconfigurable topological phononic crystal based on the magnetic attraction of a neodymium iron boron substrate, which can achieve directional control of the propagation path under a surface wave waveguide. Waveguide control is achieved by independently encoding and adjusting the angle of each cell. After coupling, the surface wave will form a topological boundary state at the set waveguide position. By adjusting the cell angle, the waveguide and the topological boundary state can be changed, thus achieving the purpose of coded reconfigurable topological waveguide transmission.

[0068] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for encoding reconfigurable topological phononic crystal waveguides, characterized in that, Includes the following steps: S1. A reconfigurable topological phononic crystal structure is designed using a neodymium iron boron (NdFeB) substrate. This structure consists of several phononic crystal supercells, each with a top-bottom symmetry. The NdFeB substrate is symmetrically distributed on the upper and lower surfaces of an aluminum plate. The surface wave pseudospin modes are controlled by adjusting the angle of the carbon steel scatterer on the NdFeB substrate. The topological Chern number C of each supercell is also adjusted. K Construct topological edge states; S2. Based on the reconfigurable topological phononic crystal structure obtained in step S1, calculate the supercell dispersion curve of the in-situ scatterer and obtain the K-point feature. S3. Adjust the angle of the scatterer. α Calculate the corresponding cell dispersion curve and obtain the K-point feature to obtain the corresponding topological Chern number C. K Phononic crystals; S4. Construct a strip phononic crystal by combining the two phononic crystal supercells obtained in step S3, calculate the dispersion curve and obtain the edge state characteristics, obtain the edge state frequency band, and realize the coded reconfigurable phononic crystal waveguide method.

2. The coded reconfigurable topological phononic crystal waveguide method according to claim 1, characterized in that, The angle of the corresponding scatterer is adjusted mechanically.

3. The coded reconfigurable topological phononic crystal waveguide method according to claim 1, characterized in that, The NdFeB substrate has a circular structure.

4. The coded reconfigurable topological phononic crystal waveguide method according to claim 1, characterized in that, In step S1, the material parameters in the reconfigurable topological phonon crystal structure include: the carbon steel density, Young's modulus, and Poisson's ratio of the scatterer are 7890 kg / m³. 3 209 GPa, 0.269, NdFeB substrate density, Young's modulus, and Poisson's ratio are 7500 kg / m³. 3 160 GPa, 0.24, density, Young's modulus, and Poisson's ratio of 6061 aluminum plate are 2700 kg / m³. 3 70 GPa, 0.33; structural parameters include: a= 25 mm , R= 12 mm , s= 11 mm , w= 4 mm , α= 0 , l= 10 mm , t= 0.5 mm , h= 4 mm .

5. The coded reconfigurable topological phononic crystal waveguide method according to claim 1, characterized in that, In step S2, the finite element model and Floquet periodic boundary are set in the COMSOL simulation software, and the dispersion curve of the in-situ scattering supercell is calculated along the wave vector direction of the first simplest Brillouin zone of the lattice.

6. The coded reconfigurable topological phononic crystal waveguide method according to claim 1, characterized in that, In step S3, the finite element model and Floquet periodic boundary are set in the COMSOL simulation software, and the dispersion curve of the supercell is calculated along the wave vector direction of the first simplest Brillouin zone of the lattice.

7. The coded reconfigurable topological phononic crystal waveguide method according to claim 6, characterized in that, scatterer angle α =-30 or α =30 .

8. The coded reconfigurable topological phononic crystal waveguide method according to claim 1, characterized in that, In step S4, the finite element model and Floquet periodic boundary are set in the COMSOL simulation software, and the dispersion curve of the strip phononic crystal is calculated along the horizontal wave vector direction to obtain the edge state characteristics and the edge state frequency band.

Images