A 3D-printed cement-based multilayer perforated plate sound-absorbing structure and its design method

Abstract

This invention discloses a 3D-printed cement-based multi-layer perforated plate sound-absorbing structure and its design method. This 3D-printed cement-based multi-layer perforated plate sound-absorbing structure utilizes the numerous pores inherent in the cement-based material. Combined with the design of the top perforated plate, sound waves entering the 3D-printed cement-based multi-layer perforated plate sound-absorbing structure undergo resonance, friction, reflection, and interference. The internal cavities regulate the sound wave propagation path and enhance the sound absorption effect. This multi-layered structure design allows the 3D-printed cement-based multi-layer perforated plate sound-absorbing structure to exhibit excellent sound absorption performance over a wide frequency range. Furthermore, the design method of this invention combines solid specimen measurement and simulation to pre-determine the structural parameters for optimal sound absorption performance within the target external dimensions. Combined with 3D printing technology, a 3D-printed cement-based multi-layer perforated plate sound-absorbing structure with the optimal sound absorption coefficient within the target external dimensions can be obtained.

Description

Technical Field

[0001] This invention belongs to the field of sound absorption and noise reduction technology, specifically a 3D printed cement-based multilayer perforated plate sound absorption structure and its design method. Background Technology

[0002] With the rapid development of modern science and technology, a large amount of environmental pollution has also followed. Noise has gradually become one of the sources of pollution that endanger human health. Traditional sound absorption methods include porous material sound absorption and resonant sound absorption. Although they can alleviate noise problems to a certain extent, they still have limitations. Porous sound-absorbing materials generally refer to solids containing cavities, channels, or pores. When sound waves propagate within them, they rub against the material matrix, thereby achieving the purpose of sound energy dissipation. Although porous sound-absorbing materials perform well in high-frequency noise conditions, they are difficult to absorb low-frequency sound waves. The noise encountered in industrial manufacturing processes is characterized by strong randomness and wide frequency range, which porous sound-absorbing materials cannot meet. Resonant sound-absorbing structures utilize resonance characteristics to dissipate energy. When the sound wave is at the same frequency as the structure's natural frequency, the structure resonates, thereby absorbing sound energy. Although this sound absorption method has a significant sound absorption effect at specific frequencies, its sound absorption bandwidth is narrow, limiting its widespread application.

[0003] Perforated panels, as a type of resonant sound-absorbing structure, have been extensively studied by scholars due to their advantages such as simple structure, environmental friendliness, and light weight. However, a drawback of perforated panels is their narrow sound absorption bandwidth, which has long been the reason why they have not been able to replace porous materials in the field of sound absorption. Therefore, it is necessary to design a sound-absorbing structure with broadband sound absorption capabilities.

[0004] The micro-perforated plate sound-absorbing structure disclosed in CN115731912A is based on the principle of coupled resonance sound absorption of a folded cavity (composed of a folded cavity and an incident cavity) and a micro-perforated plate. It employs a subwavelength sound-absorbing structure, where the incident sound wave passes perpendicularly through the micro-perforated plate into the folded cavity. Because the wavelength of the low-frequency sound wave is much larger than the cross-sectional size of the channel, the sound wave propagates freely within the folded channel and interacts with the perforated plate to generate a coupling effect, thus achieving sound absorption. However, due to limitations in resonance characteristics, its peak bandwidth is relatively narrow, failing to meet the requirements of broadband sound absorption. Furthermore, as the sound absorption bandwidth widens, the overall thickness of the structure also increases, failing to achieve the goal of space saving. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a 3D-printed cement-based multilayer perforated plate sound-absorbing structure and its design method, which exhibits excellent sound absorption performance. The design method combines solid specimen measurement and simulation to pre-determine the structural parameters for optimal sound absorption performance within the target external dimensions. Combined with 3D printing technology, a 3D-printed cement-based multilayer perforated plate sound-absorbing structure with the optimal sound absorption coefficient within the target external dimensions can be obtained, demonstrating significant practical application value.

[0006] The technical solution adopted by the present invention to solve the aforementioned technical problem is as follows: a 3D printed cement-based multi-layer perforated plate sound-absorbing structure is designed, characterized in that its external shape is a cylinder, and its internal structure specifically includes a top perforated plate (100), an inner perforated plate (200), a side wall (4), and a bottom plate (5). The top perforated plate (100) is parallel to the bottom plate (5), and the top perforated plate (100), the side wall (4), and the bottom plate (5) are connected together from top to bottom to form a cylinder; at least one inner perforated plate (200) parallel to the top perforated plate (100) is provided in the cavity (300) between the top perforated plate (100) and the bottom plate (5);

[0007] The cavity (300) on the side near the top perforated plate (100) is the incident cavity (310), and the remaining cavity is the internal cavity (320). The incident cavity (310) and the internal cavity (320) have the same cross-sectional area.

[0008] The through holes (110) on the top perforated plate (100) and the through holes (210) on the inner perforated plate (200) are the same in size and number and are positioned directly opposite each other along the axial direction of the cylinder.

[0009] Furthermore, this invention provides a design method for a 3D-printed cement-based multilayer perforated plate sound-absorbing structure. The method is applicable to the 3D-printed cement-based multilayer perforated plate sound-absorbing structure described above, and includes the following steps:

[0010] S1: Use a powder 3D printer to manufacture a solid cylindrical cement-based specimen with the target external dimensions, and then measure the sound absorption coefficient of the obtained solid cylindrical cement-based specimen with the target external dimensions to obtain its sound absorption coefficient curve.

[0011] S2: The acoustic properties of the solid cylindrical cement-based specimen in S1 are described using the JCA model. The formula for calculating the sound absorption coefficient α is as follows:

[0012]

[0013] In the formula: ρ eq For dynamic mass density, α ∞Let be the tortuosity factor, ρ0 be the air equilibrium density, and j be the imaginary unit, and j 2 =-1, ω is the angular frequency, ∧ is the viscous characteristic length, ∧' is the thermal characteristic length, σ is the flow resistance, γ is the specific heat ratio of air, P r Let P0 be Planck's coefficient, P0 be air pressure, and c0 be the speed of sound in air. ρ0, γ, and P are the porosity of the porous material, and η is the aerodynamic viscosity; where ρ0, γ, and P are... r P0, c0, and η are known quantities;

[0014] S3: The porosity of the solid cylindrical cement-based specimen in S1 was obtained by mercury intrusion porosimetry. Then, the sound frequency range of the sound absorption coefficient curve in S1 is selected at fixed intervals, starting from 0Hz, with discrete frequency points f. i The corresponding sound absorption coefficient is defined as A mea (f i This refers to the measured sound absorption coefficient value; it will be measured at frequency point f. i The sound absorption coefficient calculated by the JCA model is defined as follows: The sound absorption coefficient value obtained from the simulation is used as the objective function:

[0015]

[0016] In the formula, f i This represents the frequency value of the sound wave. For flow resistance σ and tortuosity factor α ∞ An array of viscous characteristic length ∧ and thermal characteristic length ∧', i.e., the target parameter array; Let A be the objective function. mea (f i The value is the actual measured sound absorption coefficient. The sound absorption coefficient value is obtained from the simulation calculation; N is the number of selected discrete frequency points;

[0017] porosity Value, frequency point f i Substituting into the JCA model, the Nelder-Mead method is used to find the value of the objective parameter array corresponding to the minimum value of the objective function through iterative search, that is, the optimal value of the objective parameter array;

[0018] S4: Based on the target external dimensions of the solid cylindrical cement-based specimen in S1, the porosity obtained in S3, and the values ​​of the optimal target parameter array, and combined with the known quantities in S2, according to the construction of the 3D printed cement-based multi-layer perforated plate sound-absorbing structure as described above, the thickness of the sidewall (4) and the thickness of the bottom plate (5) are set. Geometric modeling is performed in COMSOL, and the sound absorption performance of the 3D printed cement-based multi-layer perforated plate sound-absorbing structure with different internal detail dimensions under the target external dimensions is simulated to obtain the internal detail dimension data of the simulated multi-layer perforated plate sound-absorbing structure with the best sound absorption performance and the corresponding optimal frequency range; the internal detail dimensions include the perforation rate of the top perforated plate (100), the diameter of the through holes on the top perforated plate (100), the thickness of the top perforated plate (100), the thickness and number of the internal perforated plates (210), and the thickness of the incident cavity.

[0019] S5: Based on the target external dimensions of the solid cylindrical cement-based specimen in S1, combined with the internal detailed dimension data of the simulated multi-layer perforated plate structure with the best sound absorption performance obtained in S4, and the set thickness of the side wall (4) and the thickness of the bottom plate (5), a 3D model is established and manufactured using a powder 3D printer to obtain the 3D printed cement-based multi-layer perforated plate sound absorption structure.

[0020] Compared with existing technologies, the 3D-printed cement-based multi-layer perforated plate sound-absorbing structure designed in this invention has several advantages. First, the cement-based material has a large number of pores, making it a porous material with sound energy absorption capabilities. Second, the presence of the top perforated plate causes sound waves to resonate inside the 3D-printed cement-based multi-layer perforated plate sound-absorbing structure, achieving sound wave dissipation. The through-holes on the internal perforated plate generate friction with the sound waves entering the 3D-printed cement-based multi-layer perforated plate sound-absorbing structure, dissipating sound energy. In addition, the multi-layer structure design of the 3D-printed cement-based multi-layer perforated plate sound-absorbing structure requires sound waves to undergo multiple reflections and interferences during propagation. The incident cavity and the internal perforated plate can absorb and reflect sound waves to a certain extent, while the internal cavity plays a role in adjusting the sound wave propagation path and enhancing the sound absorption effect. This multi-layer structure design allows the 3D-printed cement-based multi-layer perforated plate sound-absorbing structure to exhibit good sound absorption performance over a wide frequency range. Furthermore, the design method for 3D printed cement-based multi-layer perforated plate sound-absorbing structure of the present invention combines solid specimen measurement and simulation methods to obtain the structural parameters of the target external dimensions with the optimal sound absorption performance in advance. Combined with 3D printing technology, a 3D printed cement-based multi-layer perforated plate sound-absorbing structure with the optimal sound absorption coefficient of the target external dimensions can be obtained, which has strong practical application value. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the internal structure of an embodiment of the 3D-printed cement-based multilayer perforated plate sound-absorbing structure of the present invention (section view along the longitudinal plane).

[0022] Figure 2 This is a schematic diagram of the external structure of an embodiment of the 3D printed cement-based multilayer perforated plate sound-absorbing structure of the present invention.

[0023] Figure 3 The results are the measurement and simulation results of the sound absorption coefficient of the 3D printed cement-based multilayer perforated plate sound-absorbing structure in Example 1.

[0024] Figure 4 The results are the measurement and simulation results of the sound absorption coefficient of the 3D printed cement-based multilayer perforated plate sound-absorbing structure in Example 2.

[0025] Figure 5 The results are the measurement and simulation results of the sound absorption coefficient of the 3D printed cement-based multilayer perforated plate sound-absorbing structure in Example 3.

[0026] In the figure: 100—top perforated plate; 110—top perforation; 200—internal perforated plate; 210—internal perforation; 300—cavity; 310—injection cavity; 320—internal cavity; 4—side wall; 5—bottom plate. Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0028] This invention provides a 3D-printed cement-based multi-layer perforated plate sound-absorbing structure, manufactured using 3D printing technology. The printing material used is a cement-based porous sound-absorbing material. See [link to relevant documentation]. Figures 1 to 2 The 3D printed cement-based multi-layer perforated plate sound-absorbing structure is an integrated structure with an external cylindrical shape. Its internal structure includes a top perforated plate (100), an internal perforated plate (200), a side wall (4), and a bottom plate (5). The top perforated plate (100) is parallel to the bottom plate (5). The top perforated plate (100), the side wall (4), and the bottom plate (5) are connected together from top to bottom to form a cylinder. At least one internal perforated plate (200) parallel to the top perforated plate (100) is provided in the cavity (300) between the top perforated plate (100) and the bottom plate (5).

[0029] The cavity (300) on the side near the top perforated plate (100) is the incident cavity (310), and the remaining cavity is the internal cavity (320). The incident cavity (310) and the internal cavity (320) have the same cross-sectional area.

[0030] The through holes (110) on the top perforated plate (100) and the through holes (210) on the inner perforated plate (200) are the same in size and number and are positioned directly opposite each other along the axial direction of the cylinder.

[0031] As one embodiment, the multi-layer perforated plate structure is a cylinder with a diameter of 30 mm and a thickness of 35 mm.

[0032] As one embodiment, the diameter of the through hole (110) on the top perforated plate (100) is 3 mm.

[0033] As one embodiment, the sidewall (4) has a thickness of 1.5 mm and the bottom plate (5) has a thickness of 5 mm.

[0034] Optionally, the perforation rate of the top perforated plate (100) is 6%, 9%, 12% or 16%, the thickness of the top perforated plate (100) is 3mm to 12mm, and the thickness of the inner perforated plate (200) is 3mm to 12mm.

[0035] Furthermore, the present invention provides a design method for a 3D-printed cement-based multilayer perforated plate sound-absorbing structure. This design method is applicable to the aforementioned 3D-printed cement-based multilayer perforated plate sound-absorbing structure and includes the following steps:

[0036] S1: A solid cylindrical cement-based specimen with a target external size is manufactured using a powder 3D printer. As an example, this is specifically a cylindrical cement-based specimen with a thickness of 35 mm and a diameter of 30 mm. Then, the sound absorption coefficient of the obtained solid cylindrical cement-based specimen with the target external size is measured to obtain its sound absorption coefficient curve.

[0037] S2: The acoustic properties of the solid cylindrical cement-based specimen in S1 are described using the JCA (Johnson-Champoux-Allard) model. The JCA model is an important theoretical model for describing the propagation characteristics of sound waves in porous media. Solving acoustic problems requires a set of macroscopic parameters of the material, including porosity. Flow resistance σ, tortuosity factor α ∞ The formulas for calculating the sound absorption coefficient α, based on the viscous characteristic length ∧ and the thermal characteristic length ∧', are as follows:

[0038]

[0039]

[0040] In the formula: ρ eq For dynamic mass density, α ∞ Let be the tortuosity factor, ρ0 be the air equilibrium density, and j be the imaginary unit, and j 2=-1, ω is the angular frequency, ∧ is the viscous characteristic length, ∧' is the thermal characteristic length, σ is the flow resistance, γ is the specific heat ratio of air, P r Let P0 be Planck's coefficient, P0 be air pressure, and c0 be the speed of sound in air. ρ0, γ, and P are the porosity of the porous material, and η is the aerodynamic viscosity; where ρ0, γ, and P are... r P0, c0, and η are known quantities.

[0041] S3: The porosity of the solid cylindrical cement-based specimen in S1 was obtained by mercury intrusion porosimetry. Then, the sound frequency range of the sound absorption coefficient curve in S1 is selected as discrete frequency points starting from 0Hz at 100Hz intervals. In this embodiment, 50 discrete frequency points are selected, and the frequency points f are... i The corresponding sound absorption coefficient is defined as A mea (f i This refers to the measured sound absorption coefficient value; it will be measured at frequency point f. i The sound absorption coefficient calculated by the JCA model is defined as follows: The sound absorption coefficient value obtained from the simulation is used as the objective function:

[0042]

[0043] In the formula, f i This represents the frequency value of the sound wave. For flow resistance σ and tortuosity factor α ∞ An array of viscous characteristic length ∧ and thermal characteristic length ∧', i.e., the target parameter array; Let A be the objective function. mea (f i The value is the actual measured sound absorption coefficient. This represents the sound absorption coefficient value obtained from simulation calculations. N is the number of selected discrete frequency points.

[0044] porosity Value, frequency point f i Substituting into the JCA model, the Nelder-Mead method is used to iteratively search for the minimum value of the objective function, which corresponds to the value of the objective parameter array, i.e., the optimal value of the objective parameter array.

[0045] The above Nelder-Mead method is existing technology. For its specific implementation process, please refer to the following literature: Nelder JA, Mead RA Simplex Method for Function Minimization[J].The Computer Journal,1964,7(4):308-313.

[0046] Porosity The optimal non-acoustic parameters of the specimen are obtained by using the optimal objective parameter array as the optimal non-acoustic parameters. The final optimal non-acoustic parameters of the solid cylindrical cement-based specimen in S1 are shown in Table 1:

[0047] Table 1 Optimal values ​​of nonacoustic parameters

[0048]

[0049] S4: Based on the target external dimensions of the solid cylindrical cement-based specimen in S1, the porosity obtained in S3, and the values ​​of the optimal target parameter array, and combined with the known quantities in S2, according to the above-mentioned construction of the 3D printed cement-based multi-layer perforated plate sound-absorbing structure, the thickness of the sidewall (4) and the thickness of the bottom plate (5) are set. Geometric modeling is performed in COMSOL, and the sound absorption performance of the 3D printed cement-based multi-layer perforated plate sound-absorbing structure with different internal detail dimensions under the target external dimensions is simulated to obtain the internal detail dimension data of the simulated multi-layer perforated plate sound-absorbing structure with the best sound absorption performance and the corresponding optimal frequency range. The internal detail dimensions include the perforation rate of the top perforated plate (100), the diameter of the through holes on the top perforated plate (100), the thickness of the top perforated plate (100), the thickness and number of the internal perforated plates (210), and the thickness of the incident cavity.

[0050] S5: Based on the target external dimensions of the solid cylindrical cement-based specimen in S1, combined with the internal detailed dimensions of the simulated multi-layer perforated plate sound-absorbing structure with the best sound absorption performance obtained in S4, and the set thickness of the side wall (4) and the thickness of the bottom plate (5), a 3D model is established and manufactured using a powder 3D printer to obtain the 3D printed cement-based multi-layer perforated plate sound-absorbing structure.

[0051] When the target outer dimensions are a diameter of 30 mm and a thickness of 35 mm, the thickness of the sidewall (4) is set to 1.5 mm, the thickness of the bottom plate (5) is set to 5 mm, and the diameter of the through hole (110) on the top perforated plate (100) is set to 3 mm. Three sets of 3D printed cement-based multilayer perforated plate sound-absorbing structures are set to verify the effect of the design method of the present invention. Among them, the other specific dimensional parameters of the 3D printed cement-based multilayer perforated plate sound-absorbing structure in Example 1 are: the perforation rate is 16%, the thickness of the top perforated plate is 3 mm, and the thickness of the incident cavity is 7 mm; two internal perforated plates are set, the thickness of the first internal perforated plate is 3 mm, the thickness of the first internal cavity is 7 mm, the thickness of the second internal perforated plate is 7 mm, and the thickness of the second internal cavity is 3 mm. Figure 3 The results are the measurement (i.e., experimental) and simulation results of the sound absorption coefficient of the 3D printed cement-based multilayer perforated plate sound-absorbing structure in Example 1.

[0052] The internal structural dimensions of the 3D-printed cement-based multilayer perforated sound-absorbing structure in Example 2 are as follows: perforation rate of 16%, thickness of top perforated plate of 3mm, thickness of incident cavity of 12mm, thickness of inner perforated plate of 3mm, and thickness of inner cavity of 12mm. Figure 4 The results are the measurement (i.e., experimental) and simulation results of the sound absorption coefficient of the 3D printed cement-based multilayer perforated plate sound-absorbing structure in Example 2.

[0053] The internal structural dimensions of the 3D-printed cement-based multilayer perforated sound-absorbing structure in Example 3 are as follows: perforation rate of 6%, thickness of the top perforated plate of 3mm, thickness of the incident cavity of 7mm, and two internal perforated plates are provided. The thickness of the first internal perforated plate is 3mm and the thickness of the internal cavity is 7mm, and the thickness of the second internal perforated plate is 7mm and the thickness of the internal cavity is 3mm. Figure 5 The results are the measurement (i.e., experimental) and simulation results of the sound absorption coefficient of the 3D printed cement-based multilayer perforated plate sound-absorbing structure in Example 1.

[0054] The results show that the 3D-printed cement-based multilayer perforated plate sound-absorbing structure in the embodiment exhibits excellent sound absorption performance, with a maximum sound absorption coefficient of 0.98. When the sound absorption coefficient is above 0.6, its sound absorption bandwidth is 3847Hz, 3223Hz, and 3285Hz, respectively, achieving broadband sound absorption. Comparison between the actual measured sound absorption coefficient and the simulated sound absorption coefficient proves the feasibility of the design method of this invention.

[0055] The working principle of this invention's cement-based multi-layer perforated plate sound-absorbing structure is as follows: The sound absorption capacity of the cement-based perforated plate depends on the design of its surface perforations. When sound waves are incident on the perforated plate, resonance is utilized to achieve sound absorption. The perforated design significantly increases the contact area between the cement-based material and the air, making it easier for sound waves to penetrate the material's interior during propagation. In addition to the increased contact area with air due to the perforated design, the rough surface of the cement-based material itself also generates frictional energy dissipation when sound waves are incident on the perforated plate, further enhancing the sound absorption effect.

[0056] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A 3D-printed cement-based multilayer perforated plate sound-absorbing structure, characterized in that, Its external shape is a cylinder, and its internal structure specifically includes a top perforated plate (100), an inner perforated plate (200), a side wall (4), and a bottom plate (5). The top perforated plate (100) is parallel to the bottom plate (5), and the top perforated plate (100), the side wall (4), and the bottom plate (5) are connected together from top to bottom to form a cylinder. At least one inner perforated plate (200) parallel to the top perforated plate (100) is provided in the cavity (300) between the top perforated plate (100) and the bottom plate (5). The cavity (300) on the side near the top perforated plate (100) is the incident cavity (310), and the remaining cavity is the internal cavity (320). The incident cavity (310) and the internal cavity (320) have the same cross-sectional area. The through holes (110) on the top perforated plate (100) and the through holes (210) on the inner perforated plate (200) are the same in size and number and are positioned directly opposite each other along the axial direction of the cylinder.

2. The 3D-printed cement-based multilayer perforated plate sound-absorbing structure according to claim 1, characterized in that, This 3D-printed cement-based multi-layer perforated sound-absorbing structure is an integral structure manufactured using 3D printing technology, and the printing material used is cement-based porous sound-absorbing material.

3. The 3D-printed cement-based multilayer perforated plate sound-absorbing structure according to claim 1, characterized in that, The 3D-printed cement-based multi-layer perforated sound-absorbing structure is a cylinder with a diameter of 30mm and a thickness of 35mm.

4. The 3D-printed cement-based multi-layer perforated plate sound-absorbing structure according to claim 3, characterized in that, The diameter of the through hole (110) on the top perforated plate (100) is 3 mm.

5. The 3D-printed cement-based multi-layer perforated plate sound-absorbing structure according to claim 3, characterized in that, The thickness of the sidewall (4) is 1.5 mm, and the thickness of the bottom plate (5) is 5 mm.

6. The 3D-printed cement-based multilayer perforated plate sound-absorbing structure according to claim 1, characterized in that, The perforation rate of the top perforated plate (100) is 6%, 9%, 12%, or 16%.

7. The 3D-printed cement-based multi-layer perforated plate sound-absorbing structure according to claim 3, characterized in that, The thickness of the top perforated plate (100) is 3mm to 12mm, and the thickness of the inner perforated plate (200) is 3mm to 12mm.

8. A design method for a 3D-printed cement-based multilayer perforated plate sound-absorbing structure, characterized in that, The design method is applicable to the 3D-printed cement-based multilayer perforated plate sound-absorbing structure as described in any one of claims 1-7, and the design method includes the following steps: S1: Use a powder 3D printer to manufacture a solid cylindrical cement-based specimen with the target external dimensions, and then measure the sound absorption coefficient of the obtained solid cylindrical cement-based specimen with the target external dimensions to obtain its sound absorption coefficient curve. S2: The acoustic properties of the solid cylindrical cement-based specimen in S1 are described using the JCA model. The formula for calculating the sound absorption coefficient α is as follows: In the formula: ρ eq For dynamic mass density, α ∞ Let be the tortuosity factor, ρ0 be the air equilibrium density, and j be the imaginary unit, and j 2 =-1, ω is the angular frequency, ∧ is the viscous characteristic length, ∧' is the thermal characteristic length, σ is the flow resistance, γ is the specific heat ratio of air, P r Let P0 be Planck's coefficient, P0 be air pressure, and c0 be the speed of sound in air. η is the porosity of the porous material, and η is the aerodynamic viscosity. Wherein, ρ0, γ, P r P0, c0, and η are known quantities; S3: The porosity of the solid cylindrical cement-based specimen in S1 was obtained by mercury intrusion porosimetry. Then, the sound frequency range of the sound absorption coefficient curve in S1 is selected at fixed intervals, starting from 0Hz, with discrete frequency points f. i The corresponding sound absorption coefficient is defined as A mea (f i This refers to the measured sound absorption coefficient value; it will be measured at frequency point f. i The sound absorption coefficient calculated by the JCA model is defined as follows: The sound absorption coefficient value obtained from the simulation is used as the objective function: In the formula, f i This represents the frequency value of the sound wave. For flow resistance σ and tortuosity factor α ∞ An array of viscous characteristic length ∧ and thermal characteristic length ∧', i.e., the target parameter array; Let A be the objective function. mea (f i The value is the actual measured sound absorption coefficient. The sound absorption coefficient value is obtained from the simulation calculation; N is the number of selected discrete frequency points; porosity Value, frequency point f i Substituting into the JCA model, the Nelder-Mead method is used to find the value of the objective parameter array corresponding to the minimum value of the objective function through iterative search, that is, the optimal value of the objective parameter array; S4: Based on the target external dimensions of the solid cylindrical cement-based specimen in S1, the porosity obtained in S3, and the values ​​of the optimal target parameter array, and combined with the known quantities in S2, according to the construction of the 3D printed cement-based multi-layer perforated plate sound-absorbing structure as described in any one of claims 1-7, the thickness of the sidewall (4) and the thickness of the bottom plate (5) are set, and geometric modeling is performed in COMSOL. The sound absorption performance of the 3D printed cement-based multi-layer perforated plate sound-absorbing structure with different internal detail dimensions under the target external dimensions is simulated to obtain the internal detail dimension data of the simulated multi-layer perforated plate sound-absorbing structure with the best sound absorption performance and the corresponding optimal frequency range; the internal detail dimensions include the perforation rate of the top perforated plate (100), the diameter of the through holes on the top perforated plate (100), the thickness of the top perforated plate (100), the thickness and number of the internal perforated plates (210), and the thickness of the incident cavity. S5: Based on the target external dimensions of the solid cylindrical cement-based specimen in S1, combined with the internal detailed dimensions of the simulated multi-layer perforated plate sound-absorbing structure with the best sound absorption performance obtained in S4, and the set thickness of the side wall (4) and the thickness of the bottom plate (5), a 3D model is established and manufactured using a powder 3D printer to obtain the 3D printed cement-based multi-layer perforated plate sound-absorbing structure.

9. The design method for a 3D-printed cement-based multilayer perforated plate sound-absorbing structure according to claim 8, characterized in that, In S3, the fixed interval is 100Hz.

10. The design method for a 3D-printed cement-based multilayer perforated plate sound-absorbing structure according to claim 8, characterized in that, In S3, N is 50.

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