Modulus and density decoupling mechanical metamaterial design method and device

Abstract

The invention discloses a modulus and density decoupling mechanical metamaterial design method and device, and the method comprises the steps: building a metamaterial lattice geometric model based on a hexagonal structure; and adding circular mass blocks with set mass at set positions on symmetrical edges of the lattice geometric model. Based on the homogenization theory, solving the metamaterial modulus and the metamaterial density under the set radius and the set wall thickness of the circular mass block respectively by controlling a single variable to obtain the metamaterial modulus and the metamaterial density; decoupling the metamaterial modulus and the metamaterial mass by adjusting the radius of the circular mass block; and calculating propagation data of the longitudinal waves and the transverse waves in the metamaterial by setting a calculation strategy to obtain a change rule of the sound velocity along with the density of the metamaterial. The sound velocity can be adjusted in a large range, and the technical bottleneck that high modulus and low sound velocity are difficult to obtain at the same time is broken through.

Description

Technical Field

[0001] The present invention relates to the technical field of new concept materials, and particularly relates to a design method and device for a mechanical metamaterial with decoupled modulus and density. Background Art

[0002] A metamaterial is an artificial composite material with extraordinary physical properties. By designing its microstructure in an orderly manner, it can break through the limitations of certain natural laws and generate physical properties that natural materials do not possess. Mechanical metamaterials are a major category in the research field of metamaterials, which can achieve novel mechanical properties such as negative Poisson's ratio and compression-torsion conversion, and also have broad application prospects in anti-impact, vibration reduction and noise reduction, and medical treatment. Regarding the structural innovation design of mechanical metamaterials to obtain more novel mechanical properties has also become the mainstream of current research, but the research on the coupling relationship between the modulus and density of mechanical metamaterials is less.

[0003] Currently, 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 the modulus. Therefore, it is difficult to obtain both high modulus and low sound speed at the same time. Exploring a decoupled design method for modulus and density is expected to break through the technical bottleneck that it is difficult to have both high modulus and low sound speed, and also has great application prospects in the fields of acoustic and vibration control.

[0004] Therefore, how to invent a design method for a mechanical metamaterial with decoupled modulus and density to break through the technical bottleneck that it is difficult to have both high modulus and low sound speed has become an urgent problem to be solved. Summary of the Invention

[0005] To this end, the present invention provides a design method and device for a mechanical metamaterial with decoupled modulus and density. By changing the structure of the suspended mass block, the decoupling of modulus and density is achieved, and then the large-range adjustable sound speed is realized, breaking through the technical bottleneck that it is difficult to have both high modulus and low sound speed.

[0006] To achieve the above object, the present invention provides the following technical solutions: A design method for a mechanical metamaterial with decoupled modulus and density, comprising:

[0007] Based on a hexagonal structure, a geometric model of the metamaterial lattice is constructed; circular mass blocks with a set mass are added at set positions on the symmetric sides of the lattice geometric model;

[0008] Based on the homogenization theory, by controlling a single variable, the metamaterial modulus and the metamaterial density under the set radius and set wall thickness of the circular mass block are respectively solved to obtain the metamaterial modulus and the metamaterial density; the decoupling of the metamaterial modulus and the metamaterial mass is achieved by adjusting the radius of the circular mass block;

[0009] By setting a calculation strategy, calculate the propagation data of longitudinal waves and transverse waves in the metamaterial to obtain the variation law of the sound speed with the density of the metamaterial.

[0010] As an optimal solution of a mechanical metamaterial design method for decoupling modulus and density, during the process of adding circular mass blocks with the set mass at the set positions on the symmetric sides of the lattice geometric model, the wall thickness parameter of the metamaterial lattice geometric model is t_thick, with a range of 0.5 - 2.5 mm; the radius range of the circular mass blocks is 1 - 4 mm.

[0011] As an optimal solution of a mechanical metamaterial design method for decoupling modulus and density, the steps for solving the metamaterial modulus are as follows:

[0012] Perform simulations through COMSOL software to obtain a node equivalent model;

[0013] Calculate the characteristic frequency through the modulus matrix and mass matrix in the node equivalent model;

[0014] Solve the Helmholtz equation according to the characteristic frequency to obtain the sound speed;

[0015] According to the sound speed, calculate the equivalent Young's modulus of the metamaterial through the Christoffel equation in COMSOL software;

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

[0017] As an optimal solution of a mechanical metamaterial design method for decoupling modulus and density, the calculation formula for 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; u is the displacement of each point of the model.

[0020] As an optimal solution of a mechanical metamaterial design method for decoupling modulus and density, the steps for obtaining the variation law of the sound speed with the density of the metamaterial are as follows:

[0021] Based on the node equivalent model, calculate the propagation speed of sound waves in different structural models in COMSOL Multiphysics software;

[0022] Compare the propagation speed with the radius change of the circular mass blocks to obtain the influence of the radius change of the circular mass blocks on the propagation speed;

[0023] Draw an image of the sound speed varying with the relative density according to the influence.

[0024] The present invention also provides a mechanical metamaterial design device for decoupling modulus and density. Based on the above mechanical metamaterial design method for decoupling modulus and density, it includes:

[0025] A lattice geometry model construction module for constructing a metamaterial lattice geometry model based on a hexagonal structure; adding circular mass blocks with a set mass at set positions on the symmetric edges of the lattice geometry model;

[0026] A metamaterial modulus and metamaterial density acquisition module for solving the metamaterial modulus and metamaterial density under the set radius and set wall thickness of the circular mass blocks respectively by controlling a single variable based on the homogenization theory, to obtain the metamaterial modulus and the metamaterial density; decoupling the metamaterial modulus and the metamaterial mass by adjusting the radius of the circular mass blocks;

[0027] A sound velocity variation law with density acquisition module for calculating the propagation data of longitudinal waves and transverse waves in the metamaterial through setting a calculation strategy, to obtain the variation law of the sound velocity with the metamaterial density.

[0028] As a preferred scheme of a mechanical metamaterial design device for decoupling modulus and density, in the lattice geometry model construction module, during the process of adding the circular mass blocks with the set mass at the set positions on the symmetric edges of the lattice geometry model, the wall thickness parameter of the metamaterial lattice geometry model is t_thick, with a range of 0.5 - 2.5 mm; the radius range of the circular mass blocks is 1 - 4 mm.

[0029] As a preferred scheme of a mechanical metamaterial design device for decoupling modulus and density, in the metamaterial modulus and metamaterial density acquisition module, the solution sub-module for the metamaterial modulus includes:

[0030] A node equivalent model acquisition sub-module for obtaining a node equivalent model through simulation with COMSOL software;

[0031] A characteristic frequency acquisition sub-module for calculating and obtaining the characteristic frequency through the modulus matrix and mass matrix in the node equivalent model;

[0032] A sound velocity acquisition sub-module for solving the Helmholtz equation according to the characteristic frequency to obtain the sound velocity;

[0033] An equivalent Young's modulus calculation sub-module for calculating and obtaining the equivalent Young's modulus of the metamaterial through the Christoffel equation of COMSOL software according to the sound velocity;

[0034] A variation trend plotting sub-module for plotting the variation trend of the equivalent Young's modulus in a set direction with the equivalent density.

[0035] As a preferred solution for a mechanical metamaterial design device with decoupled modulus and density, in the characteristic frequency acquisition sub-module of the metamaterial modulus and metamaterial density acquisition module, the calculation formula for the characteristic frequency is:

[0036] ([K] - ω 2 [M])[u] = 0

[0037] Where 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.

[0038] As a preferred solution for a mechanical metamaterial design device with decoupled modulus and density, in the sound velocity variation law acquisition module, the sub-module for obtaining the variation law of the sound velocity with the metamaterial density includes:

[0039] The acoustic wave velocity calculation sub-module, which is used to calculate and obtain the propagation velocity of acoustic waves in different structural models in the COMSOL Multiphysics software based on the node equivalent model;

[0040] The influence acquisition sub-module of the change in the radius of the mass block on the sound velocity, which is used to compare the propagation velocity with the change in the radius of the circular mass block to obtain the influence of the change in the radius of the circular mass block on the propagation velocity;

[0041] The variation image drawing sub-module, which is used to draw the variation image of the sound velocity with the relative density according to the influence.

[0042] The present invention has the following advantages: Based on a hexagonal structure, a geometric model of a metamaterial lattice is constructed; circular mass blocks with a set mass are added at set positions on the symmetric sides of the lattice geometric model; based on the homogenization theory, by controlling a single variable, the metamaterial modulus and the metamaterial density are respectively solved for the circular mass blocks with a set radius and a set wall thickness, obtaining the metamaterial modulus and the metamaterial density; the metamaterial modulus and the metamaterial mass are decoupled by adjusting the radius of the circular mass block; by setting a calculation strategy, the propagation data of longitudinal and transverse waves in the metamaterial are calculated, obtaining the variation law of the sound speed with the metamaterial density. Compared with the coupling relationship between the modulus and density of general materials, the present invention can make the modulus and density of the material adjustable separately. Since the sound speed is positively correlated with the ratio of the Young's modulus to the density, the present invention also makes it possible to adjust the sound speed of low-speed sound waves. The structure with added mass blocks shows an obvious decreasing trend in the Young's modulus with the increase of the equivalent density in both the x and y directions compared to the hexagonal structure without mass block distribution; observing the trend of the image shows that different relative densities can correspond to the same modulus, and different Young's moduli can also correspond to the same density, realizing the decoupling of the Young's modulus and density of the material. The decoupling of the Young's modulus and density enables the sound wave to grow slowly with the change of the relative density while maintaining a low speed. Adding mass blocks to the structure and changing the size of the mass blocks, the variables are simple and controllable, and the effect is significant. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0044] The structures, ratios, sizes, etc. depicted in this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have any technical substance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0045] Figure 1 It is a schematic flow chart of a design method for a mechanical metamaterial with decoupled modulus and density provided in Embodiment 1 of the present invention;

[0046] Figure 2 It is a schematic geometric structure diagram of a metamaterial with decoupled Young's modulus and density in a design method for a mechanical metamaterial with decoupled modulus and density provided in Embodiment 1 of the present invention;

[0047] Figure 3 Schematic diagram of the variation trend of the normalized equivalent Young's modulus in the x-direction with respect to the normalized equivalent density in a mechanical metamaterial design method with decoupled modulus and density provided in Embodiment 1 of the present invention;

[0048] Figure 4 Schematic diagram of the variation trend of the normalized equivalent Young's modulus in the y-direction with respect to the normalized equivalent density in a mechanical metamaterial design method with decoupled modulus and density provided in Embodiment 1 of the present invention;

[0049] Figure 5 Schematic diagram of the variation of the normalized equivalent sound velocity in the x-direction with respect to the normalized equivalent density in a mechanical metamaterial design method with decoupled modulus and density provided in Embodiment 1 of the present invention;

[0050] Figure 6 Schematic diagram of the variation of the normalized equivalent sound velocity in the y-direction with respect to the normalized equivalent density in a mechanical metamaterial design method with decoupled modulus and density provided in Embodiment 1 of the present invention;

[0051] Figure 7 Schematic diagram of the architecture of a mechanical metamaterial design device with decoupled modulus and density provided in Embodiment 2 of the present invention. Detailed implementation manners

[0052] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0053] Embodiment 1

[0054] Refer to Figure 1 , Embodiment 1 of the present invention provides a mechanical metamaterial design method with decoupled modulus and density, including the following steps:

[0055] S1. Based on a hexagonal structure, construct a geometric model of the metamaterial lattice; add circular mass blocks with a set mass at set positions on the symmetric sides of the lattice geometric model;

[0056] S2. Based on the homogenization theory, by controlling a single variable, solve the metamaterial modulus and the metamaterial density of the circular mass blocks with a set radius and a set wall thickness respectively to obtain the metamaterial modulus and the metamaterial density; decouple the metamaterial modulus and the metamaterial mass by adjusting the radius of the circular mass blocks;

[0057] S3. By setting calculation strategies, calculate the propagation data of longitudinal waves and transverse waves in the metamaterial to obtain the variation law of the sound speed with the density of the metamaterial.

[0058] In this embodiment, in step S1, based on the hexagonal structure, construct a lattice geometric model of the metamaterial; add circular mass blocks with a set mass at set positions on the symmetric sides of the lattice geometric model.

[0059] Specifically, as Figure 2 shown, based on the hexagonal honeycomb structure, construct a lattice geometric model of the metamaterial, add circular mass blocks on the four symmetric sides, and study the macroscopic mechanical properties of this structure from the perspective of the equivalent medium theory.

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

[0061] In this embodiment, in step S2, based on the homogenization theory, by controlling a single variable, solve the metamaterial modulus and the metamaterial density under the set radius and the set wall thickness of the circular mass block respectively to obtain the metamaterial modulus and the metamaterial density; decouple the metamaterial modulus and the metamaterial mass by adjusting the radius of the circular mass block.

[0062] Specifically, use integration to solve the equivalent density ρ of different structures; change the wall thickness parameter t_thick when no mass block is added, obtain the equivalent density and the equivalent Young's modulus, draw a relationship diagram between the two, and increase the radius parameter r of the circular mass block under different wall thicknesses to solve the equivalent density and the equivalent Young's modulus.

[0063] Among them, the steps for solving the metamaterial modulus are as follows:

[0064] S21. Perform simulation through COMSOL software to obtain a node equivalent model.

[0065] S22. Calculate and obtain the characteristic frequency through the modulus matrix and the mass matrix in the node equivalent model.

[0066] Specifically, the calculation formula for 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; 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 speed.

[0070] S24. Calculate the equivalent Young's modulus of the metamaterial through the Christoffel equation in COMSOL software according to the sound velocity;

[0071] S25. Plot the variation trend of the equivalent Young's modulus in a set direction with respect to the equivalent density.

[0072] Specifically, since the material is anisotropic, the sound wave directions are defined separately for x and y; as Figure 3 shown is the variation trend of the equivalent Young's modulus in the x direction with respect to the equivalent density; as Figure 4 shown is the variation trend of the equivalent Young's modulus in the y direction with respect to the equivalent density; Figure 3 And Figure 4 the dots in represent the variation trends of the modulus and the sound velocity with respect to the density when no mass block is added. Figure 3 The triangular points with different orientations in correspond to the variation trends of Ex caused by the radius of the mass block with respect to the density for different wall thicknesses. It can be seen that simply changing the radius of the mass block deviates the material properties from the coupling relationship between the Young's modulus and the density.

[0073] In this embodiment, according to Figure 3 and Figure 4 it can be known that the single corresponding relationship between the modulus and the density of the traditional material is changed, so that different trends appear in the variation of the modulus with respect to the density, realizing that the material corresponds to different moduli at the same density and different densities at the same modulus, and realizing the decoupling of the modulus and the density.

[0074] In this embodiment, in step S3, by setting the calculation strategy, the propagation data of longitudinal and transverse waves in the metamaterial are calculated to obtain the variation law of the sound velocity with respect to the density of the metamaterial.

[0075] Specifically, the steps to obtain the variation law of the sound velocity with respect to the density of the metamaterial are as follows:

[0076] S31. Based on the node equivalent model, calculate the propagation velocity of sound waves in different structural models in COMSOL Multiphysics software;

[0077] Specifically, the calculation formula for the sound wave propagation velocity is:

[0078]

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

[0080] S32. Compare the propagation velocity with the change in the radius of the circular mass block to obtain the influence of the change in the radius of the circular mass block on the propagation velocity;

[0081] S33. Draw an image of the sound velocity varying with the relative density according to the influence.

[0082] Specifically, as Figure 5 shown, it is the variation image of the sound velocity in the x direction with respect to the relative density; as Figure 6 shown, it is the variation image of the sound velocity in the y direction with respect to the relative density; Figure 5 In Figure 6 , the dots represent the variation trends of the modulus and the sound velocity with density when no mass block is added. From Figure 5 In Figure 6 , it can be seen that the sound velocity decreases as the density increases, providing a theoretical basis for the design of high-modulus and low-sound-velocity metamaterial devices.

[0083] In summary, the present invention constructs a geometric model of a metamaterial lattice based on a hexagonal structure; circular mass blocks with a set mass are added at set positions on the symmetric sides of the lattice geometric model. Based on the homogenization theory, by controlling a single variable, the modulus and density of the metamaterial are respectively solved under the set radius and set wall thickness of the circular mass blocks to obtain 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; by setting a calculation strategy, the propagation data of longitudinal and transverse waves in the metamaterial are calculated to obtain the variation law of the sound velocity with the density of the metamaterial. Compared with the coupling relationship between the modulus and density of general materials, the present invention can make the modulus and density of the material adjustable separately. Since the sound velocity is positively correlated with the ratio of the Young's modulus to the density, the present invention also makes it possible to adjust the sound velocity of low-speed sound waves. Comparing the structure with added mass blocks with the hexagonal structure without mass block distribution, the Young's modulus in both the x and y directions shows an obvious decreasing trend as the equivalent density increases; observing the image trend, it can be seen that different relative densities can correspond to the same modulus, and different Young's moduli can also correspond to the same density, realizing the decoupling of the Young's modulus and density of the material. The decoupling of the Young's modulus and density enables the sound wave to grow slowly with the change of relative density while maintaining a low speed. Adding mass blocks to the structure and changing the size of the mass blocks, the variables are simple and controllable, and the effect is remarkable.

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

[0085] It should be noted that some embodiments of the present disclosure have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the above embodiments and still achieve the desired results. Additionally, the processes depicted in the drawings do not necessarily require the particular order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0086] Embodiment 2

[0087] See Figure 7 , Embodiment 2 of the present invention further provides a mechanical metamaterial design device for decoupling modulus and density, including:

[0088] A lattice geometry model construction module 001, configured to construct a metamaterial lattice geometry model based on a hexagonal structure; add circular mass blocks with a set mass at set positions on the symmetric edges of the lattice geometry model;

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

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

[0091] In this embodiment, in the lattice geometry model construction module 001, during the process of adding the circular mass blocks with the set mass at the set positions on the symmetric edges 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 blocks is 1 - 4 mm.

[0092] In this embodiment, in the metamaterial modulus and metamaterial density acquisition module 002, the solution sub-module for the metamaterial modulus includes:

[0093] A node equivalent model acquisition sub-module 021, configured to obtain a node equivalent model through simulation by COMSOL software;

[0094] A characteristic frequency acquisition sub-module 022, configured to calculate and obtain the characteristic frequency through the modulus matrix and mass matrix in the node equivalent model;

[0095] The sound velocity acquisition sub-module 023 is used to solve the Helmholtz equation according to the characteristic frequency to obtain the sound velocity;

[0096] The equivalent Young's modulus calculation sub-module 024 is used to calculate the equivalent Young's modulus of the metamaterial through the Christoffel equation of COMSOL software according to the sound velocity;

[0097] The change trend plotting sub-module 025 is used to plot the change trend of the equivalent Young's modulus in a set direction with respect to the equivalent density.

[0098] In this embodiment, in the characteristic frequency acquisition sub-module 022 of the metamaterial modulus and metamaterial density acquisition module 002, the calculation formula of the characteristic frequency is:

[0099] ([K] - ω 2 [M])[u] = 0

[0100] Where K is the modulus matrix; M is the mass matrix; ω is the characteristic frequency; u is the displacement of each point of the model.

[0101] In this embodiment, in the sound velocity change law acquisition module 003, the sub-modules for obtaining the change law of the sound velocity with respect to the metamaterial density include:

[0102] The acoustic wave velocity calculation sub-module 031 is used to calculate the propagation velocity of acoustic waves in different structural models based on the node equivalent model in COMSOL Multiphysics software;

[0103] The influence of the change in the radius of the mass block on the sound velocity acquisition sub-module 032 is used to compare the propagation velocity with the change in the radius of the circular mass block to obtain the influence of the change in the radius of the circular mass block on the propagation velocity;

[0104] The change image plotting sub-module 033 is used to plot the change image of the sound velocity with respect to the relative density according to the influence.

[0105] It should be noted that the information interaction, execution process, etc. between the above system modules, since they are based on the same concept as the method embodiment in Embodiment 1 of the present application, bring the same technical effects as the method embodiment of the present application. For the specific content, reference can be made to the description in the method embodiment shown above in the present application, and details will not be repeated here.

[0106] Embodiment 3

[0107] Embodiment 3 of the present invention provides a non-transitory computer-readable storage medium, in which program code for a mechanical metamaterial design method with decoupled modulus and density is stored. The program code includes instructions for executing the mechanical metamaterial design method with decoupled modulus and density according to Embodiment 1 or any possible implementation thereof.

[0108] The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that integrates 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 invention provides an electronic device, including: a memory and a processor;

[0111] The processor and the memory communicate with each other through a bus; the memory stores program instructions executable by the processor, and the processor can execute the mechanical metamaterial design method with decoupled modulus and density according to Embodiment 1 or any possible implementation thereof by invoking the program instructions.

[0112] Specifically, the processor can be implemented by hardware or by 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 code stored in the memory. The memory can be integrated in the processor or can exist independently outside the processor.

[0113] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions according to the embodiments of the present invention are generated in whole or in part. 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 transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or a wireless manner (such as infrared, wireless, microwave, etc.).

[0114] Obviously, those skilled in the art should understand that the various modules or steps of the present invention described above can be implemented by a general-purpose computing system. They can be concentrated on a single computing system or distributed over a network composed of multiple computing systems. Optionally, they can be implemented by program code executable by the computing system. Thus, they can be stored in the storage system and executed by the computing system. And in some cases, the steps shown or described can be executed in a sequence different from that here, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module for implementation. In this way, the present invention is not limited to any specific combination of hardware and software.

[0115] Although the present invention has been described in detail above with general descriptions and specific embodiments, on the basis of the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A mechanical metamaterial design method for decoupling modulus and density, characterized in that: include: Based on the hexagonal structure, a metamaterial lattice geometric model is constructed; a circular mass block of a set mass is added at a set position on a symmetrical side of the lattice geometric model; Based on the homogenization theory, by controlling a single variable, the metamaterial modulus and the metamaterial density under the set radius and the set wall thickness of the circular mass are solved respectively to obtain the metamaterial modulus and the metamaterial density; Decoupling the metamaterial modulus from the metamaterial mass by adjusting the radius of the circular mass block; By setting a calculation strategy, the propagation data of longitudinal waves and transverse waves in the metamaterial are calculated to obtain the variation law of sound speed with the density of the metamaterial.

2. The method for designing a mechanical metamaterial with modulus and density decoupling according to claim 1, characterized in that: In the process of adding the circular mass block of the set mass at the set position on the symmetrical side of the lattice geometric model, the wall thickness parameter of the metamaterial lattice geometric model is t_thick, ranging from 0.5-2.5mm; the radius range of the circular mass block is 1-4mm.

3. The method for designing a mechanical metamaterial with modulus and density decoupling according to claim 2, characterized in that: The steps for solving the metamaterial modulus are: The node equivalent model is obtained by simulation using COMSOL software; The characteristic frequency is calculated by using the modulus matrix and the mass matrix in the node equivalent model; Solving the Helmholtz equation according to the characteristic frequency to obtain the sound velocity; According to the sound velocity, the equivalent Young's modulus of the metamaterial is obtained by calculating the Christoffel equation using COMSOL software; Plot the variation trend of equivalent Young's modulus versus equivalent density in a set direction.

4. The method for designing a mechanical metamaterial with modulus and density decoupling according to claim 3, characterized in that: The calculation formula of the characteristic frequency is: ([K]-ω 2 [M])[u]=0 Where K is the modulus matrix; M is the mass matrix; ω is the characteristic frequency; u is the displacement of each point in the model.

5. The method for designing a mechanical metamaterial with modulus and density decoupling according to claim 4, characterized in that: The steps of obtaining the variation law of the sound velocity with the density of the metamaterial are: Based on the node equivalent model, the propagation speed of the sound wave in different structural models is calculated in COMSOL Multiphysics software; Comparing the propagation velocity with the radius change of the circular mass block to obtain the influence of the radius change of the circular mass block on the propagation velocity; The variation of sound velocity with relative density is plotted according to the effects.

6. A mechanical metamaterial design device with modulus and density decoupling, using a mechanical metamaterial design method with modulus and density decoupling according to any one of claims 1 to 5, characterized in that: include: A lattice geometry model building module is used to build a metamaterial lattice geometry model based on a hexagonal structure; and to add a circular mass block of a set mass at a set position on a symmetrical side of the lattice geometry model; The metamaterial modulus and metamaterial density acquisition module is used to solve the metamaterial modulus and metamaterial density of the circular mass block with a set radius and a set wall thickness based on the homogenization theory by controlling a single variable, so as to obtain the metamaterial modulus and the metamaterial density; the metamaterial modulus and the metamaterial mass are decoupled by adjusting the radius of the circular mass block; The module for obtaining the law of sound velocity changing with density is used to calculate the propagation data of longitudinal waves and transverse waves in the metamaterial by setting a calculation strategy, and obtain the law of sound velocity changing with the density of the metamaterial.

7. The mechanical metamaterial design device for modulus and density decoupling according to claim 6, characterized in that: In the lattice geometry model construction module, in the process of adding a circular mass block of the set mass at the set position on the symmetrical side of the lattice geometry model, the wall thickness parameter of the metamaterial lattice geometry model is t_thick, ranging from 0.5-2.5mm; the radius range of the circular mass block is 1-4mm.

8. The mechanical metamaterial design device for modulus and density decoupling according to claim 7, characterized in that: In the metamaterial modulus and metamaterial density acquisition module, the metamaterial modulus solution submodule includes: The node equivalent model acquisition submodule is used to obtain the node equivalent model by simulation through COMSOL software; The characteristic frequency acquisition submodule is used to calculate the characteristic frequency through the modulus matrix and the mass matrix in the node equivalent model; A sound speed acquisition submodule, used for solving the Helmholtz equation according to the characteristic frequency to obtain the sound speed; An equivalent Young's modulus calculation submodule, used to calculate the equivalent Young's modulus of the metamaterial according to the sound velocity by using the Christoffel equation of COMSOL software; The variation trend drawing submodule is used to draw the variation trend of the equivalent Young's modulus with the equivalent density in the set direction.

9. The mechanical metamaterial design device for decoupling modulus and density according to claim 8, characterized in that: In the characteristic frequency acquisition submodule of the metamaterial modulus and metamaterial density acquisition module, the calculation formula of the characteristic frequency is: ([K]-ω 2 [M])[u]=0 Where K is the modulus matrix; M is the mass matrix; ω is the characteristic frequency; u is the displacement of each point in the model.

10. The mechanical metamaterial design device with modulus and density decoupling according to claim 9, characterized in that: In the module for obtaining the law of sound velocity changing with density, the submodule for obtaining the law of sound velocity changing with the density of the metamaterial includes: The acoustic wave velocity calculation submodule is used to calculate the propagation velocity of acoustic waves in different structural models in COMSOL Multiphysics software based on the node equivalent model; A submodule for obtaining the effect of the change in the radius of the mass block on the speed of sound, used for comparing the propagation speed with the change in the radius of the circular mass block to obtain the effect of the change in the radius of the circular mass block on the propagation speed; The variation image drawing submodule is used to draw an image of the variation of sound speed with relative density according to the influence.

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