A method and apparatus for designing mechanical metamaterials with decoupled modulus and density

Abstract

The application discloses a kind of modulus and density decoupling mechanical metamaterial design method and device, this method is based on hexagon structure, constructs metamaterial lattice geometry model;In the symmetry edge of the lattice geometry model, the position of setting is increased to the circular mass block of setting mass.Based on homogenization theory, by controlling single variable, respectively to the modulus of the circular mass block setting radius and the modulus of the metamaterial under the setting wall thickness and the density of the metamaterial are solved, obtain the modulus of the metamaterial and the density of the metamaterial;By adjusting the radius of the circular mass block, the modulus of the metamaterial and the mass of the metamaterial are decoupled;By setting calculation strategy, the propagation data of longitudinal wave and transverse wave in the metamaterial are calculated, and the change rule of sound velocity with the density of the metamaterial is obtained.The application can realize the wide-range adjustable of sound velocity, break the technical bottleneck that high modulus and low sound velocity are difficult to obtain.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new concept material, and particularly relates to a modulus and density decoupling mechanical metamaterial design method and device. BACKGROUND

[0002] Metamaterial is a kind of artificial composite material with super-normal physical properties. By orderly designing the microstructure, it can break through the limitation of some natural laws and produce physical properties that natural materials do not have. Mechanical metamaterial is a major category in the field of metamaterial research, which can realize novel mechanical properties such as negative Poisson's ratio and pressure-torsion conversion, and has broad application prospects in shock resistance, vibration and noise reduction, and medical treatment. The structural innovation design of mechanical metamaterial to obtain more novel mechanical properties has become the mainstream of current research, but the coupling relationship between the modulus and density of mechanical metamaterial is less studied.

[0003] At present, the modulus and density of natural materials increase and decrease together, which makes the propagation speed of sound waves in the material also increase with the increase of modulus, so it is difficult to obtain high modulus and low sound speed at the same time. Exploring the decoupling design method of modulus and density is expected to break the technical bottleneck of high modulus and low sound speed, and has great application prospect in the field of acoustics and vibration control.

[0004] Therefore, how to invent a modulus and density decoupling mechanical metamaterial design method to break the technical bottleneck of high modulus and low sound speed has become a problem to be solved. SUMMARY

[0005] Therefore, the present application provides a modulus and density decoupling mechanical metamaterial design method and device, which realizes the decoupling of modulus and density by changing the structure of the suspended mass block, and further realizes the wide-range adjustment of sound speed, breaking the technical bottleneck of high modulus and low sound speed.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme: a modulus and density decoupling mechanical metamaterial design method, comprising:

[0007] Based on the hexagonal structure, a metamaterial lattice geometric model is constructed; a circular mass block with a set mass is added at a set position on the symmetric edge of the lattice geometric model;

[0008] Based on the homogenization theory, the modulus and density of the metamaterial are solved by controlling a single variable, respectively setting the radius and wall thickness of the circular mass block, and obtaining the modulus and density of the metamaterial; the modulus and mass of the metamaterial are decoupled by adjusting the radius of the circular mass block;

[0009] The propagation data of the longitudinal wave and the transverse wave in the metamaterial is calculated by setting a calculation strategy, and a variation law of the sound velocity with the density of the metamaterial is obtained.

[0010] As a preferred solution of the modulus and density decoupling mechanical metamaterial design method, in the process of adding the circular mass block of the set mass at the set position on the symmetric edge of the lattice geometry model, the wall thickness parameter of the metamaterial lattice geometry model is t_thick, and the range is 0.5-2.5mm; the radius of the circular mass block ranges from 1mm to 4mm.

[0011] As a preferred solution of the modulus and density decoupling mechanical metamaterial design method, the solving step of the modulus of the metamaterial is:

[0012] The node equivalent model is obtained by simulation through COMSOL software;

[0013] The characteristic frequency is calculated and obtained through the modulus matrix and the mass matrix in the node equivalent model;

[0014] The Helmholtz equation is solved according to the characteristic frequency, and the sound velocity is obtained;

[0015] According to the sound velocity, the equivalent Young's modulus of the metamaterial is calculated through COMSOL software Christoffel equation;

[0016] The variation trend of the equivalent Young's modulus in the set direction with the equivalent density is drawn.

[0017] As a preferred solution of the modulus and density decoupling mechanical metamaterial design method, the calculation formula of the characteristic frequency is:

[0018] ([K]-ω 2 [M])[u]=0

[0019] In the formula, K is the modulus matrix; M is the mass matrix; ω is the characteristic frequency; and u is the displacement of each point of the model.

[0020] As a preferred solution of the modulus and density decoupling mechanical metamaterial design method, the step of obtaining the variation law of the sound velocity with the density of the metamaterial is:

[0021] Based on the node equivalent model, the propagation velocity of the sound wave in different structure models is calculated in COMSOL Multiphysics software;

[0022] The propagation velocity is compared with the radius variation of the circular mass block, and the influence of the radius variation of the circular mass block on the propagation velocity is obtained;

[0023] According to the influence, a variation image of the sound velocity with the relative density is drawn.

[0024] The application also provides a modulus and density decoupled mechanical metamaterial design device based on the above modulus and density decoupled mechanical metamaterial design method, comprising:

[0025] A crystal lattice geometry model construction module is configured to construct a metamaterial crystal lattice geometry model based on a hexagonal structure, and add a circular mass block with a set mass at a set position on a symmetric edge of the crystal lattice geometry model;

[0026] A metamaterial modulus and metamaterial density acquisition module is configured to solve metamaterial modulus and metamaterial density under a set radius and a set wall thickness of the circular mass block respectively based on a homogenization theory by controlling a single variable, and acquire the metamaterial modulus and the metamaterial density; and decouple the metamaterial modulus and the metamaterial mass by adjusting the radius of the circular mass block.

[0027] A sound speed change rule acquisition module is configured to calculate propagation data of longitudinal waves and transverse waves in the metamaterial by setting a calculation strategy, and acquire a change rule of sound speed with the metamaterial density.

[0028] As a preferred solution of the modulus and density decoupled mechanical metamaterial design device, in the process of adding the circular mass block with the set mass at the set position on the symmetric edge of the crystal lattice geometry model in the crystal lattice geometry model construction module, the wall thickness parameter of the metamaterial crystal lattice geometry model is t_thick, and the range is 0.5-2.5 mm; the radius range of the circular mass block is 1-4 mm.

[0029] As a preferred solution of the modulus and density decoupled mechanical metamaterial design device, in the metamaterial modulus and metamaterial density acquisition module, the metamaterial modulus solving submodule comprises:

[0030] A node equivalent model acquisition submodule is configured to simulate by COMSOL software to acquire a node equivalent model.

[0031] A characteristic frequency acquisition submodule is configured to calculate a characteristic frequency by a modulus matrix and a mass matrix in the node equivalent model.

[0032] A sound speed acquisition submodule is configured to solve a Helmholtz equation according to the characteristic frequency to acquire a sound speed.

[0033] An equivalent Young's modulus calculation submodule is configured to calculate an equivalent Young's modulus of the metamaterial by a COMSOL software Christoffel equation according to the sound speed.

[0034] A change trend drawing submodule is configured to draw a change trend of the equivalent Young's modulus in a set direction with the equivalent density.

[0035] As a preferred solution of the mechanical metamaterial design device for decoupling modulus and density, in the characteristic frequency obtaining submodule of the metamaterial modulus and metamaterial density obtaining module, the calculation formula of the characteristic frequency is:

[0036] ([K]-ω 2 [M])[u]=0

[0037] In the formula, K is a modulus matrix; M is a mass matrix; ω is a characteristic frequency; and u is the displacement of each point of the model.

[0038] As a preferred solution of the mechanical metamaterial design device for decoupling modulus and density, in the characteristic frequency obtaining submodule of the metamaterial modulus and metamaterial density obtaining module, the calculation formula of the characteristic frequency is:

[0039] The sound wave speed calculation submodule is configured to calculate the propagation speed of sound waves in different structure models based on the node equivalent model in the COMSOL Multiphysics software.

[0040] The mass block radius change influence obtaining submodule is configured to compare the propagation speed with the radius change of the circular mass block, and obtain the influence of the radius change of the circular mass block on the propagation speed.

[0041] The change image drawing submodule is configured to draw a change image of the sound speed with the relative density according to the influence.

[0042] The present application has the following advantages: the present application is based on a hexagonal structure, a metamaterial lattice geometry model is constructed, a circular mass block with a set mass is added at a set position on the symmetric edge of the lattice geometry model, based on the homogenization theory, the metamaterial modulus and the metamaterial density are solved under the condition of a single variable, the metamaterial modulus and the metamaterial density are obtained, the metamaterial modulus and the metamaterial mass are decoupled by adjusting the radius of the circular mass block, the propagation data of longitudinal waves and transverse waves in the metamaterial are calculated by setting a calculation strategy, and the change rule of the sound velocity with the metamaterial density is obtained. Compared with the coupling relationship between the modulus and the density of general materials, the modulus and the density of the material can be adjusted independently, and because the ratio of the sound velocity and the Young's modulus is positively correlated with the density, the present application also makes it possible to adjust the sound velocity of low-speed sound waves. The structure with the added mass block has a significant decreasing trend of the Young's modulus with the equivalent density in the x and y directions compared with the hexagonal structure without the mass block distribution; it can be known from the image trend that different relative densities can be corresponded to the same modulus, and different Young's moduli can be corresponded to the same density, so that the decoupling of the Young's modulus and the density of the material is realized. The decoupling of the Young's modulus and the density makes the sound wave be able to slowly grow with the relative density while keeping a low speed. The variable is simple and controllable, and the effect is significant. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can be derived from the provided drawings without creative labor.

[0044] The structures, proportions, sizes, etc. shown in the specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and do not define the limiting conditions for the implementation of the present application, so they do not have technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the present application, should still fall within the scope covered by the disclosed technical content.

[0045] Figure 1 A design method flowchart of a modulus and density decoupled mechanical metamaterial provided in embodiment 1 of the present application;

[0046] Figure 2 A geometric structure schematic diagram of a metamaterial with decoupled Young's modulus and density in a modulus and density decoupled mechanical metamaterial design method provided in embodiment 1 of the present application;

[0047] Figure 3 Figure 1 is a schematic diagram of the trend of the normalized equivalent Young's modulus in the x direction varying with the normalized equivalent density according to the method for designing a modulus and density decoupled mechanical metamaterial provided in Embodiment 1 of the present application;

[0048] Figure 4 Figure 2 is a schematic diagram of the trend of the normalized equivalent Young's modulus in the y direction varying with the normalized equivalent density according to the method for designing a modulus and density decoupled mechanical metamaterial provided in Embodiment 1 of the present application;

[0049] Figure 5 Figure 3 is a schematic diagram of the trend of the normalized equivalent sound speed in the x direction varying with the normalized equivalent density according to the method for designing a modulus and density decoupled mechanical metamaterial provided in Embodiment 1 of the present application;

[0050] Figure 6 Figure 4 is a schematic diagram of the trend of the normalized equivalent sound speed in the y direction varying with the normalized equivalent density according to the method for designing a modulus and density decoupled mechanical metamaterial provided in Embodiment 1 of the present application;

[0051] Figure 7 Figure 5 is a schematic diagram of the architecture of a device for designing a modulus and density decoupled mechanical metamaterial provided in Embodiment 2 of the present application. DETAILED DESCRIPTION

[0052] The present application is described and explained more fully by specific reference to the drawings set forth below, in which specific embodiments of the application are shown. As would be obvious to those of ordinary skill in the art, the described embodiments are merely preferred embodiments of the application and do not limit the scope of the application. Based on the embodiments described herein, one of ordinary skill in the art would readily understand the general principles of the application and would readily recognize that other embodiments can be utilized and "substantially equivalent" elements can be substituted without departing from the application.

[0053] Embodiment 1

[0054] Reference Figure 1 Embodiment 1 of the present application provides a method for designing a modulus and density decoupled mechanical metamaterial, comprising the following steps:

[0055] S1, based on a hexagonal structure, a metamaterial lattice geometry model is constructed; a circular mass block with a set mass is added at a set position on the symmetric edge of the lattice geometry model;

[0056] S2, based on the homogenization theory, the metamaterial modulus and the metamaterial density under the condition of a set radius of the circular mass block and a set wall thickness are solved by controlling a single variable, and the metamaterial modulus and the metamaterial density are obtained; the metamaterial modulus and the metamaterial mass are decoupled by adjusting the radius of the circular mass block;

[0057] S3, calculate the propagation data of the longitudinal wave and the transverse wave in the metamaterial by setting a calculation strategy, and obtain the variation law of the sound velocity with the density of the metamaterial.

[0058] In this embodiment, in step S1, a metamaterial lattice geometric model is constructed based on a hexagonal structure; a circular mass block with a set mass is added at a set position on a symmetric edge of the lattice geometric model;

[0059] Specifically, as shown in the figure, a metamaterial lattice geometric model is constructed based on a hexagonal honeycomb structure, and a circular mass block is added to the symmetric four edges, and the macro mechanical properties of the structure are studied from the perspective of equivalent medium theory. Figure 2

[0060] The wall thickness parameter of the metamaterial lattice geometric model is t_thick, and the range is 0.5-2.5mm; the radius of the circular mass block ranges from 1 to 4mm.

[0061] In this embodiment, in step S2, based on the homogenization theory, the metamaterial modulus and the metamaterial density under the condition of setting the radius and setting the wall thickness of the circular mass block are solved by controlling a single variable, and the metamaterial modulus and the metamaterial density are obtained; the metamaterial modulus and the metamaterial mass are decoupled by adjusting the radius of the circular mass block.

[0062] Specifically, the integral is used to solve the equivalent density ρ of different structures; when no mass block is added, the wall thickness parameter t_thick is changed, the equivalent density and the equivalent Young's modulus are solved, and the relationship diagram is drawn; the radius parameter r of the circular mass block is increased under different wall thicknesses, and the equivalent density and the equivalent Young's modulus are solved.

[0063] The solving step of the metamaterial modulus is:

[0064] S21, simulate by COMSOL software to obtain a node equivalent model;

[0065] S22, calculate the characteristic frequency by using the modulus matrix and the mass matrix in the node equivalent model;

[0066] Specifically, the calculation formula of the characteristic frequency is:

[0067] ([K]-ω 2 [M])[u]=0

[0068] In the formula, K is the modulus matrix; M is the mass matrix; ω is the characteristic frequency; and u is the displacement of each point of the model.

[0069] S23, solve the Helmholtz equation according to the characteristic frequency to obtain the sound velocity;

[0070] ​S24, according to the sound velocity, the equivalent Young's modulus of the metamaterial is obtained by calculating Christoffel equation through COMSOL software;

[0071] S25, the change trend of the equivalent Young's modulus in the set direction with the equivalent density is drawn.

[0072] Specifically, because the material is anisotropic, the sound wave direction is defined according to x and y respectively; as Figure 3 The change trend of the equivalent Young's modulus in the x direction with the equivalent density is shown in the figure; as Figure 4 The change trend of the equivalent Young's modulus in the y direction with the equivalent density is shown in the figure; Figure 3 And Figure 4 The circle point in the figure represents the change trend of the modulus and the sound velocity with the density when no mass block is added. Figure 3 The triangular points in different directions in the figure correspond to the change trend of Ex with the density caused by the radius of the mass block when the wall thickness is different. It can be seen that simply changing the radius of the mass block makes the material property deviate from the coupling relationship between Young's modulus and density.

[0073] In this embodiment, according to Figure 3 And Figure 4 It can be seen that the relationship between the modulus and the density of the traditional material is changed, the change trend of the modulus with the density appears different, the material corresponds to different modulus under the same density, and the material corresponds to different density under the same modulus, and the decoupling of the modulus and the density is realized.

[0074] In this embodiment, in step S3, the propagation data of the longitudinal wave and the transverse wave in the metamaterial is calculated by setting the calculation strategy, and the change law of the sound velocity with the density of the metamaterial is obtained.

[0075] Specifically, the step of obtaining the change law of the sound velocity with the density of the metamaterial is:

[0076] S31, based on the node equivalent model, the propagation speed of the sound wave in different structure models is calculated in COMSOL Multiphysics software;

[0077] Specifically, the calculation formula of the sound wave propagation speed is:

[0078]

[0079] In the formula, c is the sound wave propagation speed; f is the acoustic frequency; and k is the wave number.

[0080] S32, the change of the radius of the circular mass block is compared with the propagation speed, and the influence of the change of the radius of the circular mass block on the propagation speed is obtained;

[0081] S33, according to the influence, the change image of the sound velocity with the relative density is drawn.

[0082] Specifically, such as Figure 5 The image shown is a graph illustrating the variation of sound velocity in the x-direction with relative density; as shown... Figure 6 The image shown is a graph of the sound velocity in the y-direction as a function of relative density. Figure 5 and Figure 6 In the diagram, the dots represent the changes in modulus and velocity of sound with density when no mass is added. From... Figure 5 and Figure 6 As can be seen from this, the speed of sound decreases with increasing density, providing a theoretical basis for the design of high-modulus, low-speed metamaterial devices.

[0083] In summary, this invention constructs a metamaterial lattice geometric model based on a hexagonal structure; a circular mass block of a predetermined mass is added at a predetermined position on the symmetrical side of the lattice geometric model. Based on homogenization theory, the metamaterial modulus and density are obtained by controlling a single variable and solving for the circular mass block with a predetermined radius and wall thickness; the metamaterial modulus and density are decoupled from the metamaterial mass by adjusting the radius of the circular mass block; and the propagation data of longitudinal and transverse waves in the metamaterial are calculated by setting a calculation strategy to obtain the variation law of sound velocity with the metamaterial density. Compared with the general coupling relationship between material modulus and density, this invention enables the material modulus and density to be independently adjustable. Since the sound velocity and the ratio of Young's modulus to density are positively correlated, this invention also makes it possible to adjust the sound velocity of low-speed sound waves. Compared to the hexagonal structure without mass blocks, the structure with added mass blocks exhibits a significant decreasing trend in Young's modulus in both the x and y directions with increasing equivalent density. Observing the trend in the image reveals that different relative densities correspond to the same modulus, and different Young's moduli correspond to the same density, achieving decoupling between the material's Young's modulus and density. This decoupling allows sound waves to increase slowly with changes in relative density while maintaining a low velocity. Adding mass blocks and varying their size in the structure provides simple, controllable variables with significant effects.

[0084] It should be noted that the method of this disclosure embodiment can be executed by a single device, such as a computer or server. The method of this embodiment can also be applied to a distributed scenario, where multiple devices cooperate to complete the task. In such a distributed scenario, one of these devices may execute only one or more steps of the method of this disclosure embodiment, and the multiple devices will interact with each other to complete the method described.

[0085] It is to be understood that the foregoing description is directed to some embodiments of the disclosure. Other embodiments fall within the scope of the following claims. In some cases, the actions or steps recited in the claims can be performed in a different order and still achieve desirable results. Additionally, processes depicted in the figures do not necessarily require the particular order shown or sequential order to achieve desirable results. In certain implementations, multitasking and parallel processing can be advantageous.

[0086] Embodiment 2

[0087] Referring to Figure 7 Embodiment 2 of the present application also provides a mechanical metamaterial design device with decoupled modulus and density, comprising:

[0088] A lattice geometry model construction module 001 is configured to construct a metamaterial lattice geometry model based on a hexagonal structure, and add a circular mass block with a set mass at a set position on a symmetric edge of the lattice geometry model;

[0089] A metamaterial modulus and metamaterial density acquisition module 002 is configured to solve metamaterial modulus and metamaterial density under a set radius of the circular mass block and a set wall thickness of the metamaterial respectively based on a homogenization theory by controlling a single variable, and obtain the metamaterial modulus and the metamaterial density; and decouple the metamaterial modulus and the metamaterial mass by adjusting the radius of the circular mass block.

[0090] A sound speed variation with density rule acquisition module 003 is configured to calculate propagation data of longitudinal waves and transverse waves in the metamaterial by setting a calculation strategy, and obtain a variation rule of sound speed with the metamaterial density.

[0091] In the present embodiment, in the process of adding the circular mass block with the set mass at the set position on the symmetric edge of the lattice geometry model in the lattice geometry model construction module 001, the wall thickness parameter of the metamaterial lattice geometry model is t_thick, and the range is 0.5-2.5mm; the radius of the circular mass block ranges from 1mm to 4mm.

[0092] In the present embodiment, in the metamaterial modulus and metamaterial density acquisition module 002, the solving submodule of the metamaterial modulus comprises:

[0093] A node equivalent model acquisition submodule 021 is configured to obtain a node equivalent model by simulation through COMSOL software;

[0094] A characteristic frequency acquisition submodule 022 is configured to calculate and obtain a characteristic frequency through a modulus matrix and a mass matrix in the node equivalent model;

[0095] The sound speed obtaining submodule 023 is configured to solve a Helmholtz equation according to the characteristic frequency to obtain a sound speed.

[0096] The equivalent Young's modulus calculation submodule 024 is configured to calculate an equivalent Young's modulus of the metamaterial by a Christoffel equation of COMSOL software according to the sound speed.

[0097] The change trend drawing submodule 025 is configured to draw a change trend of the equivalent Young's modulus in a set direction with respect to the equivalent density.

[0098] In the embodiment, in the characteristic frequency obtaining submodule 022 of the metamaterial modulus and metamaterial density obtaining module 002, the calculation formula of the characteristic frequency is as follows:

[0099] ([K]-ω 2 [M])[u]=0

[0100] In the formula, K is a modulus matrix, M is a mass matrix, ω is a characteristic frequency, and u is a displacement of each point of the model.

[0101] In the embodiment, in the sound speed change rule with respect to density obtaining module 003, the submodule for obtaining the change rule of the sound speed with respect to the metamaterial density comprises:

[0102] The sound wave speed calculation submodule 031 is configured to calculate a propagation speed of a sound wave in different structure models in COMSOL Multiphysics software based on a node equivalent model.

[0103] The mass block radius change influence on sound speed obtaining submodule 032 is configured to compare the propagation speed with a radius change of a circular mass block to obtain an influence of the radius change of the circular mass block on the propagation speed.

[0104] The change image drawing submodule 033 is configured to draw a change image of the sound speed with respect to the relative density according to the influence.

[0105] It should be noted that the information interaction and execution process between the modules of the system described above are based on the same concept as the method embodiment in Embodiment 1 of the present application, and the technical effects brought by the method embodiment are the same as those of the method embodiment of the present application. For specific content, refer to the description of the method embodiment described above. Here, no further description is given.

[0106] Embodiment 3

[0107] Embodiment 3 of the present application provides a non-transitory computer readable storage medium, which stores a program code of a design method of a modulus and density decoupled mechanical metamaterial, the program code comprising instructions for performing the design method of a modulus and density decoupled mechanical metamaterial of embodiment 1 or any possible implementation manner thereof.

[0108] The computer readable storage medium can be any available medium or a data storage device such as a server, data center, etc. integrated with one or more available media. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk (SSD)), etc.

[0109] Embodiment 4

[0110] Embodiment 4 of the present application provides an electronic device, comprising a memory and a processor.

[0111] The processor and the memory complete mutual communication through a bus; the memory stores program instructions executable by the processor, and the processor calling the program instructions can perform the design method of a modulus and density decoupled mechanical metamaterial of embodiment 1 or any possible implementation manner thereof.

[0112] Specifically, the processor can be implemented by hardware or software, when implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor, which is implemented by reading software codes stored in a memory, the memory can be integrated in the processor or exist independently outside the processor.

[0113] In the above embodiments, all or part of them can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of them can be implemented in the form of a computer program product. The computer program product comprises one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable systems. The computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another, for example, the computer instructions can be transferred from one website, computer, server or data center to another through wired (for example, coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (for example, infrared, wireless, microwave, etc.) manner.

[0114] It should be apparent to those skilled in the art that the modules or steps of the application described above can be implemented with a general purpose computing system, which can be centralized on a single computing system or distributed on a network of multiple computing systems, and optionally implemented with program codes executable by a computing system, which can be stored in a storage system and executed by a computing system, and in some cases, the steps shown or described can be executed in an order different from that shown here, or made into individual integrated circuit modules, or made into a single integrated circuit module with multiple modules or steps. Thus, the application is not limited to any particular combination of hardware and software.

[0115] Although the application has been fully described above with particularity with reference to the general description and examples, modifications or improvements can be made to the application, which will be apparent to those skilled in the art. Thus, these modifications or improvements made without departing from the spirit of the application are within the scope of the application claimed.

Claims

1. A method of designing a mechanical metamaterial with decoupled modulus and density, characterized in that, The application relates to a method for calculating the modulus and density of metamaterials. The method comprises the following steps: Based on a hexagonal structure, a metamaterial lattice geometry model is constructed; a circular mass block with a set mass is added to a set position on a symmetric edge of the lattice geometry model; Based on the homogenization theory, the modulus and density of the metamaterials under the condition of a set radius and a set wall thickness of the circular mass block are solved by controlling a single variable, and the modulus and density of the metamaterials are obtained; The modulus of the metamaterials is decoupled from the mass of the metamaterials by adjusting the radius of the circular mass block; Solving equivalent density of different structures by integral ; change the wall thickness parameter t thick when no mass block is added, obtain the equivalent density and the equivalent Young's modulus, and draw the relationship diagram; increase the radius parameter r of the circular mass block under different wall thicknesses, and solve the equivalent density and the equivalent Young's modulus; The propagation data of longitudinal waves and transverse waves in the metamaterials are calculated by setting a calculation strategy, and the variation law of the sound velocity with the density of the metamaterials is obtained; The solving step of the modulus of the metamaterials is as follows: A node equivalent model is obtained by simulation through COMSOL software; The characteristic frequency is calculated through the modulus matrix and the mass matrix in the node equivalent model; The Helmholtz equation is solved according to the characteristic frequency, and the sound velocity is obtained; The equivalent Young's modulus of the metamaterials is calculated through the COMSOL software Christoffel equation according to the sound velocity; The variation trend of the equivalent Young's modulus in a set direction with the equivalent density is drawn; where K is the stiffness matrix; M is the mass matrix; is the characteristic frequency; u is the displacement of each point of the model; The calculation formula of the characteristic frequency is as follows: The step of obtaining the variation law of the sound velocity with the density of the metamaterials is as follows: Based on the node equivalent model, the propagation velocity of sound waves in different structure models is calculated in the COMSOL Multiphysics software; The influence of the radius variation of the circular mass block on the propagation velocity is obtained by comparing the propagation velocity with the radius variation of the circular mass block; 2. The method of designing a mechanical metamaterial with decoupled modulus and density according to claim 1, wherein, According to the influence, a variation image of the sound velocity with the relative density is drawn.

3. A device for designing a mechanical metamaterial with decoupled modulus and density, using the method of designing a mechanical metamaterial with decoupled modulus and density according to any one of claims 1-2, characterized in that, In the process of adding the circular mass block with the set mass to the set position on the symmetric edge of the lattice geometry model, the wall thickness parameter of the metamaterial lattice geometry model is t_thick, and the range is 0.5-2.5 mm; the radius range of the circular mass block is 1-4 mm. The application relates to a method for calculating the modulus and density of metamaterials. The method comprises the following steps: Based on a hexagonal structure, a metamaterial lattice geometry model is constructed; a circular mass block with a set mass is added to a set position on a symmetric edge of the lattice geometry model; 4. The design apparatus of a mechanical metamaterial decoupled in modulus and density of claim 3, wherein, Based on the homogenization theory, the modulus and density of the metamaterials under the condition of a set radius and a set wall thickness of the circular mass block are solved by controlling a single variable, and the modulus and density of the metamaterials are obtained; The modulus of the metamaterials is decoupled from the mass of the metamaterials by adjusting the radius of the circular mass block; The propagation data of longitudinal waves and transverse waves in the metamaterials are calculated by setting a calculation strategy, and the variation law of the sound velocity with the density of the metamaterials is obtained; The solving step of the modulus of the metamaterials is as follows: A node equivalent model is obtained by simulation through COMSOL software; The characteristic frequency is calculated through the modulus matrix and the mass matrix in the node equivalent model; The Helmholtz equation is solved according to the characteristic frequency, and the sound velocity is obtained; The equivalent Young's modulus of the metamaterials is calculated through the COMSOL software Christoffel equation according to the sound velocity; The variation trend of the equivalent Young's modulus in a set direction with the equivalent density is drawn; The calculation formula of the characteristic frequency is as follows: The step of obtaining the variation law of the sound velocity with the density of the metamaterials is as follows: Based on the node equivalent model, the propagation velocity of sound waves in different structure models is calculated in the COMSOL Multiphysics software; The influence of the radius variation of the circular mass block on the propagation velocity is obtained by comparing the propagation velocity with the radius variation of the circular mass block; According to the influence, a variation image of the sound velocity with the relative density is drawn. In the process of adding the circular mass block with the set mass to the set position on the symmetric edge of the lattice geometry model, the wall thickness parameter of the metamaterial lattice geometry model is t_thick, and the range is 0.5-2.5 mm; the radius range of the circular mass block is 1-4 mm.

5. The design apparatus of a mechanical metamaterial decoupled in modulus and density of claim 4, wherein, The metamaterial modulus and the metamaterial density acquisition module, the solving submodule of the metamaterial modulus includes: A node equivalent model acquisition submodule is configured to obtain a node equivalent model by COMSOL software simulation; A characteristic frequency acquisition submodule is configured to calculate a characteristic frequency by using a modulus matrix and a mass matrix in the node equivalent model; A sound speed acquisition submodule is configured to solve a Helmholtz equation according to the characteristic frequency to obtain a sound speed; An equivalent Young's modulus calculation submodule is configured to calculate an equivalent Young's modulus of the metamaterial by COMSOL software Christoffel equation according to the sound speed; A change trend drawing submodule is configured to draw a change trend of the equivalent Young's modulus in a set direction with respect to the equivalent density.

6. The design apparatus of a mechanical metamaterial decoupled in modulus and density of claim 5, wherein, In the characteristic frequency acquisition submodule of the metamaterial modulus and the metamaterial density acquisition module, the calculation formula of the characteristic frequency is: where K is the stiffness matrix; M is the mass matrix; is the characteristic frequency; and u is the displacement of each point of the model.

7. The design apparatus of a mechanically metamaterial with decoupled modulus and density according to claim 6, wherein, In the sound speed change rule acquisition module, the submodule for obtaining the sound speed change rule with respect to the metamaterial density includes: A sound wave speed calculation submodule is configured to calculate a propagation speed of a sound wave in different structure models in COMSOL Multiphysics software based on the node equivalent model; A mass block radius change influence on sound speed acquisition submodule is configured to compare the propagation speed with a radius change of a circular mass block to obtain an influence of the radius change of the circular mass block on the propagation speed; A change image drawing submodule is configured to draw a change image of the sound speed with respect to the relative density according to the influence.

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