Closed-cell foamed aluminum acoustic performance simulation method based on Voronoi model

Abstract

The invention relates to the technical field of material simulation, and discloses a closed-cell foamed aluminum acoustic performance simulation method based on a Voronoi model, which comprises the following steps: model construction: constructing a three-dimensional solid model of closed-cell foamed aluminum with adjustable porosity, aperture and wall thickness parameters based on the Voronoi principle; performing model optimization: performing homogenization processing on a Voronoi polyhedral structure in the three-dimensional entity model by adopting a random point homogenization algorithm so as to improve the quality of the model; and acoustic simulation: importing the optimized three-dimensional solid model into finite element simulation software, building a simulation model, and calculating the sound absorption performance or sound insulation performance of the simulation model. According to the method, the technical problems that an existing simulation model is distorted and the grid quality is poor are solved, the accuracy and reliability of a simulation result are remarkably improved by constructing the solid model which is accurate in geometry and uniform in structure, and a set of complete and verifiable technical method is provided for acoustic performance prediction and structural design of the closed-cell foamed aluminum.

Description

Technical Field

[0001] This invention relates to the field of materials simulation technology, specifically to a method for simulating the acoustic properties of closed-cell aluminum foam based on the Voronoi model. Background Technology

[0002] Closed-cell aluminum foam, as a new type of multifunctional material integrating structure and function, has shown broad application prospects in aerospace, rail transportation and construction engineering due to its light weight, high specific strength and excellent energy absorption, vibration reduction and acoustic performance. Among them, its complex internal porous structure is the key to achieving sound absorption and noise reduction and sound insulation performance. In the product research and development and design stage, accurate prediction of its acoustic performance is crucial for guiding the structural optimization of the material.

[0003] Currently, research on the acoustic properties of closed-cell aluminum foam largely relies on physical experiments. While this method is direct and reliable, it has limitations such as long preparation cycles, high costs, and difficulty in conducting systematic parameterization studies. Therefore, using computer simulation as an alternative or auxiliary means has become a technological development trend in this field. However, how to accurately construct a digital model that can reflect its true random microstructure is a key bottleneck in achieving effective simulation.

[0004] Existing simulation modeling methods have several shortcomings. Some methods use idealized regular geometries (such as hexahedrons or tetrahedrons) to stack and approximate the internal structure of aluminum foam. This oversimplified model is far removed from the complex topology of real aluminum foam, and therefore simulation results based on such models often deviate significantly from experimental data, making it difficult to meet engineering accuracy requirements. To more realistically simulate its morphology, some technical solutions use the Voronoi diagram principle for modeling. However, in practice, a common approach is to generate a Voronoi sheet model without thickness and then assign it a thickness attribute. This method produces geometric interference and volume overlap at the boundaries of polyhedra, leading to errors in the subsequent finite element mesh generation stage, making acoustic simulation impossible or distorting the results. In addition, the initial Voronoi model generated from purely random points often has a highly uneven distribution of internal pore sizes, with some pores that are too large or too small. This not only does not match the pore morphology of the actual material but also seriously affects the quality of the simulation mesh, thereby reducing the reliability of the calculation results.

[0005] Although CT scan reconstruction technology can obtain high-fidelity models, its high equipment cost and time consumption limit its widespread application in routine product development and design optimization. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a simulation method for the acoustic performance of closed-cell aluminum foam based on the Voronoi model. This method solves the problems in existing technologies, such as geometric interference caused by using sheet thickening for modeling, and low model quality caused by uneven pore size distribution, which leads to difficulties in simulation mesh generation, low accuracy of calculation results, and insufficient reliability.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a simulation method for the acoustic performance of closed-cell aluminum foam based on the Voronoi model, comprising the following steps: Model construction: Based on the Voronoi principle, a three-dimensional solid model of the closed-cell aluminum foam with adjustable porosity, pore size and wall thickness parameters is constructed.

[0008] In one specific implementation, this step involves bidirectionally offsetting the bisecting faces of the Voronoi polyhedron to form hole walls with a set wall thickness, thereby constructing the three-dimensional solid model that avoids the problem of overlapping wall thicknesses.

[0009] Specifically, the equations of the two perpendicular bisectors after offset can be expressed as: ; in, , , Let be the coordinates of any point on the offset perpendicular bisector plane; , , The coordinates are the midpoint of the line connecting the two random points before the offset. , , Let be the unit normal vector component of the bisecting plane; The thickness is the wall thickness of the three-dimensional solid model.

[0010] Model optimization: A random point homogenization algorithm is used to homogenize the Voronoi polyhedral structure in the 3D solid model to improve the model quality.

[0011] In one specific implementation, the random point homogenization algorithm operates as follows: After generating the initial Voronoi polyhedron, the random nucleation points of each polyhedron are adjusted to the centroid position of the polyhedron through multiple iterations until the three-dimensional solid model with uniform aperture distribution is obtained. Furthermore, the algorithm also includes improving the spatial distribution uniformity of the initial nucleation points by setting and constraining the minimum distance between any two points when generating the initial nucleation points.

[0012] Acoustic simulation: The optimized three-dimensional solid model is imported into finite element simulation software to build a simulation model and calculate its sound absorption or sound insulation performance.

[0013] In one specific implementation, before proceeding to this step, the porosity of the three-dimensional solid model is first calculated using the following formula. : ; in, The porosity of the three-dimensional solid model; The volume occupied by the skeleton in the three-dimensional solid model; The total volume of the three-dimensional solid model.

[0014] Specifically, when calculating the sound absorption performance, this step performs virtual perforation on the three-dimensional solid model and calculates its sound absorption coefficient at different frequencies in finite element simulation software. When calculating the sound insulation performance, this step uses the three-dimensional solid model without perforation and calculates its sound insulation at different frequencies in finite element simulation software.

[0015] Experimental verification: A closed-cell aluminum foam sample with parameters consistent with the three-dimensional solid model was fabricated, and experimental data was obtained through acoustic impedance tube testing. The results were then compared and verified with those from the acoustic simulation steps.

[0016] In one specific implementation, the sample is processed using a medium-speed wire EDM or a high-speed EDM machine to ensure that the geometric parameters of the sample are consistent with the parameters of the three-dimensional solid model.

[0017] In one specific embodiment, the model building step is implemented in ABAQUS software through its Python script interface; the acoustic simulation step is performed in the COMSOL multiphysics simulation platform.

[0018] This invention provides a simulation method for the acoustic performance of closed-cell aluminum foam based on the Voronoi model. It has the following beneficial effects: 1. This invention constructs a three-dimensional solid model with real wall thickness by bidirectionally offsetting the bisecting plane of the Voronoi polyhedron. This method structurally avoids the volume overlap problem at the polyhedron interface when assigning thickness to the traditional shell model. The non-interference characteristic of this geometry ensures the correctness of subsequent finite element mesh generation, enabling the model to more accurately represent the real internal pore wall structure of closed-cell aluminum foam.

[0019] 2. This invention uses a random point homogenization algorithm to optimize the internal structure of the model. By iteratively adjusting the position of the core points, a three-dimensional solid model with uniform aperture distribution is obtained. This optimization solves the problem of poor local mesh quality or failure to mesh due to the large differences in the internal aperture size of the unprocessed Voronoi model, thereby significantly improving the convergence and accuracy of acoustic performance simulation calculations.

[0020] 3. This invention integrates the entire process of parametric modeling, targeted simulation, and experimental verification. By comparing the simulation calculation results with the measured data of physical samples processed with the same parameters, a closed-loop verification is formed, which confirms the credibility of the simulation method and provides a reliable technical basis for predicting the acoustic performance and optimizing the structure of closed-cell aluminum foam. This reduces the reliance on a large number of physical experiments in the R&D stage and shortens the product development cycle. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the two-dimensional method flow of the present invention. Figure 2 This is a two-dimensional Voronoi diagram of the present invention; Figure 3 This is a three-dimensional Voronoi diagram of the present invention; Figure 4 This is a schematic diagram comparing the two-dimensional Voronoi polygon and the closed-cell aluminum foam structure of the present invention. Figure 5 This is a schematic diagram of the three-dimensional Voronoi shell model of the present invention; Figure 6 This is a schematic diagram comparing the sheet model and the solid model of the present invention; Figure 7 This is a schematic diagram illustrating the causes of porosity errors between the sheet model and the solid model of the present invention. Figure 8 This is a schematic diagram of the unoptimized model of the present invention and closed-cell aluminum foam; Figure 9 This is a flowchart of the random point homogenization algorithm of the present invention; Figure 10 This is a schematic diagram of the Voronoi three-dimensional model obtained after random point homogenization according to the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example: Please see the appendix Figure 1 - Appendix Figure 10 This invention provides a method for simulating the acoustic performance of closed-cell aluminum foam based on the Voronoi model, including: S1. Model Construction: Based on the Voronoi principle, a three-dimensional solid model of closed-cell aluminum foam with adjustable porosity, pore size and wall thickness parameters is constructed. First, the Voronoi principle was chosen as the theoretical basis for model construction because the three-dimensional Voronoi structure is highly similar in topological morphology to the internal cellular structure of closed-cell aluminum foam prepared by melt foaming or powder metallurgy. Both are continuous polyhedral structures formed by outward growth and mutual compression from nucleation points in space. This inherent similarity allows the model built based on the Voronoi principle to better reproduce the irregular and random pore distribution characteristics of real aluminum foam in terms of morphology.

[0024] In the initial exploration of this embodiment, a direct modeling approach is: First, a set of random points are generated in a preset 3D space as the nucleation points of the Voronoi polyhedron. Then, the vertex coordinate data of each polyhedron is generated by calculation. Next, through a secondary development interface, such as using a Python script, these vertex coordinate data are imported into computer-aided engineering (CAE) software. Inside the software, by executing automated instructions to generate lines from points, stitch lines into surfaces, and combine surfaces into solids, a Voronoi shell model, also known as a sheet model, is finally generated, consisting of a large number of thin polygonal planes.

[0025] However, this sheet model has significant technical flaws, making it unsuitable for rigorous acoustic performance simulations. First, the model is merely a geometric shell without thickness, failing to accurately reflect the pore wall structure of closed-cell aluminum foam with a defined wall thickness. Second, and more critically, directly assigning thickness attributes to this sheet model in subsequent finite element analysis software will lead to severe geometric interference at the edges and vertices where different polyhedra intersect, i.e., volume overlap of wall thickness. Acoustic simulation calculations have extremely strict requirements for mesh quality, and this volume overlap will directly cause distorted meshes or even meshing failures during mesh generation, thus making simulation calculations impossible or producing unreliable results.

[0026] To address the aforementioned issues, this embodiment proposes an improved method for constructing three-dimensional solid models. The core of this method is no longer to assign thickness to the generated sheet, but to directly generate a solid structure with wall thickness during the geometry definition stage.

[0027] The specific implementation method is as follows: In the process of constructing the Voronoi polyhedron, for any two adjacent nucleation points in space, the perpendicular bisector of the line is no longer used as the final geometric interface. Instead, along the normal direction of the bisector, it is symmetrically offset to both sides by half the preset wall thickness (D / 2). Through this operation, a single bisector is transformed into two parallel planes with a distance of D between them.

[0028] This offset process can be accurately described by the following equation, where the equation of the perpendicular bisector before the offset is: ; The equations for the two parallel planes after the offset are: ; in, , , Let be the coordinates of any point on the offset perpendicular bisector plane; , , The coordinates are the midpoint of the line connecting the two random points before the offset. , , The components of the unit normal vector of the bisecting plane on each coordinate axis; This is a pre-set parameter representing the thickness of the aluminum foam pore wall.

[0029] After performing the above bidirectional offset operation on the perpendicular bisectors of all nucleation point pairs in space, the intersecting families of these offset planes naturally form a continuous network structure composed of solid hole walls with a defined wall thickness. This structure is the three-dimensional solid model of the present invention. This model fundamentally avoids the problems of geometric interference and volume overlap of wall thickness, ensuring the topological integrity and geometric correctness of the model, and providing a solid foundation for subsequent high-quality mesh generation and accurate acoustic simulation calculations.

[0030] Based on this three-dimensional solid model, its key physical parameters, such as porosity, can also be accurately calculated. It can be obtained through the following formula: ; in, Porosity of the three-dimensional solid model; This represents the total volume occupied by all the solid skeletons in the model, a value that can be accurately calculated directly by CAE software. This calculation represents the macroscopic total volume of the model, and is more accurate than methods that estimate porosity based on sheet models and approximate formulas.

[0031] Preferably, the entire process of constructing the above-mentioned three-dimensional solid model, including the generation of initial random points, Voronoi geometric calculations, bidirectional offset of the plane, and final solid assembly in CAE software (such as ABAQUS), can be achieved by writing automated scripts. By setting wall thickness D, the number and distribution of nucleation points, etc., as adjustable parameters in the script, a series of three-dimensional solid models with different microstructural characteristics such as porosity, pore size, and wall thickness can be easily generated, providing an efficient modeling tool for subsequent systematic research on the influence of structural parameters on acoustic performance.

[0032] S2. Model Optimization: A random point homogenization algorithm is used to homogenize the Voronoi polyhedral structure in the 3D solid model to improve the model quality. In this embodiment, after constructing a preliminary three-dimensional solid model of closed-cell aluminum foam through the aforementioned steps, in order to further improve the geometric quality of the model, make it more consistent with the microstructure of real closed-cell aluminum foam, and meet the stringent requirements of subsequent acoustic simulation for mesh quality, this invention provides a model optimization method.

[0033] It should be noted that while Voronoi models generated directly from a set of completely random nucleation points exhibit randomness on a macroscopic scale, they often suffer from structural inhomogeneity at the microscopic scale. Specifically, the model may contain both excessively large polyhedral pores and excessively small, distorted pores. This extreme distribution of pore size differs from the relatively concentrated pore size distribution of real aluminum foam structures prepared by the foaming method. Furthermore, in finite element analysis (especially acoustic simulation), excessively small or oddly shaped pore structures can greatly complicate mesh generation, easily producing low-quality distorted meshes or even causing mesh generation failure, thus severely affecting the convergence and accuracy of the simulation results.

[0034] To address the aforementioned technical issues, this embodiment employs a random point homogenization algorithm to homogenize the internal Voronoi polyhedral structure of the three-dimensional solid model. The core idea of ​​this algorithm is to adjust the spatial distribution of Voronoi nucleation points to guide the size and shape of the polyhedral pores to become more uniform, thereby obtaining a three-dimensional solid model with a more regular and uniform internal structure.

[0035] The specific implementation methods include the following operations: First, after generating the initial Voronoi polyhedron structure, the position coordinates of the geometric centroid of each polyhedron cell in the model are calculated. The geometric centroid is the geometric center point of the polyhedron's volume.

[0036] Next, an iterative optimization process is initiated, in which the original random nucleation point coordinates of each polyhedron are updated to the geometric centroid coordinates of the polyhedron itself. In other words, the nucleation point is moved to the center of the cell pore of the polyhedron it generates.

[0037] After all the nucleation point positions have been updated, the entire three-dimensional Voronoi structure is reconstructed based on this new set of nucleation point positions. Since the positions of the nucleation points have changed, the new Voronoi polyhedron partitions will also change accordingly.

[0038] Repeat the above iterative loop of calculating the centroid, updating the points, and reconstructing the structure. Through multiple iterations, the originally randomly located nucleation points will gradually tend towards the stable center of their respective cell pores. This will gradually reduce the size difference between the cells and make the shape more regular, thereby achieving the homogenization of the internal structure of the entire model. Preferably, the iterative process can set a maximum number of iterations or a threshold for judging convergence to control the termination of the algorithm.

[0039] Furthermore, to improve the initial uniformity of the model from the source, thereby enhancing the efficiency and effectiveness of subsequent iterative optimization, this embodiment also improves the process of generating initial random core points. Compared to using an unconstrained random function to generate the point set, a constrained permutation method is preferred. This method ensures that when generating each new random point, its distance to all existing points is greater than a preset minimum distance value.

[0040] By applying this minimum distance constraint, the initial nucleation points can be effectively prevented from forming local clusters or overly sparse regions in space. A more uniformly distributed initial set of points provides a better starting point for the subsequent centroid iteration process, thereby further improving the uniformity of the final 3D solid model.

[0041] After processing by the above random point homogenization algorithm, the internal structural features of the final obtained 3D solid model are as follows: Its polyhedral pore size distribution is more concentrated, avoiding the occurrence of extremely large or extremely small pore diameters, and the pore morphology is closer to a regular polyhedron. This optimized model not only more closely approximates the real closed-cell aluminum foam structure in terms of morphology, but more importantly, it provides a high-quality model foundation for subsequent acoustic analysis in multiphysics simulation platforms such as COMSOL, ensuring that high-quality finite element meshes can be successfully generated, thus providing the necessary prerequisites for obtaining accurate and reliable acoustic performance simulation results.

[0042] S3. Acoustic simulation: Import the optimized three-dimensional solid model into the finite element simulation software, build the simulation model and calculate its sound absorption or sound insulation performance. In this embodiment, after the construction and optimization of the three-dimensional solid model of closed-cell aluminum foam is completed, the technical solution of the present invention further includes an acoustic simulation step. The purpose of this step is to use the high-quality model obtained in the aforementioned steps, whose geometric shape and structural parameters are precisely controlled, to quantitatively predict and analyze its acoustic performance in a virtual computing environment.

[0043] Specifically, the acoustic simulation step in this embodiment begins by importing the homogenized three-dimensional solid model obtained from the aforementioned model optimization step into a finite element multiphysics simulation platform. Preferably, the platform can be COMSOL Multiphysics software, as it can handle multiphysics problems such as acoustic-structure coupling well.

[0044] After importing the model, a simulation model needs to be built to simulate the standard acoustic testing environment. In this embodiment, the simulation model is designed to simulate the testing environment of acoustic impedance tubes, which is a common standard method for testing the sound absorption and sound insulation performance of acoustic materials. For this purpose, a virtual pipe domain containing three-dimensional solid model samples needs to be constructed in the simulation platform.

[0045] The specific model settings, physics field selection, and boundary condition application vary depending on the acoustic performance to be evaluated, and are described below: Simulation of sound absorption performance: When the simulation objective is to evaluate the sound absorption performance of closed-cell aluminum foam, it is usually aimed at closed-cell aluminum foam that has been perforated. Therefore, it is necessary to first preprocess the imported three-dimensional solid model, namely virtual perforation processing. This processing is achieved by creating and arranging multiple cylindrical geometries in the model and performing Boolean subtraction operations to generate through circular channels with specific pore diameters and pore spacings on the solid skeleton. This operation transforms the originally sound-impermeable closed-cell structure into a perforated structure that allows sound waves to enter the interior.

[0046] Subsequently, this model, which has undergone virtual perforation, is placed in a virtual impedance tube. In terms of the physical field settings, the air domain inside the tube is given acoustic properties, while the solid skeleton of the aluminum foam is given solid mechanical properties.

[0047] The boundary conditions are set as follows: a sound source is set at one end of the virtual impedance tube to emit a plane wave with a specific frequency range as the incident sound wave. The sidewall of the tube is usually set as an acoustic hard boundary to simulate a rigid tube wall, and the rear surface of the model is set as a rigid backing, i.e., a total reflection boundary, which is consistent with the standard settings in actual impedance tube testing.

[0048] During the solution process, the finite element software calculates the entire process of sound wave propagation in the pipe, interaction with the perforated aluminum foam model, and reflection. By setting virtual microphone points in the incident sound field region and measuring the sound pressure information of the incident and reflected waves, the sound absorption coefficient of the model at different frequencies can be calculated based on the principles of the dual-microphone method or the standing wave ratio method.

[0049] Simulation of sound insulation performance: When the simulation objective is to evaluate the sound insulation performance of closed-cell aluminum foam, a three-dimensional solid model that retains its complete closed-cell structure without any perforation is used. The core of this simulation process lies in solving the acoustic-structural coupling problem.

[0050] In this scenario, the virtual testing environment is divided into three domains: The sound field includes the incident sound field, the solid domain containing the three-dimensional solid model, and the transmitted sound field. A plane wave sound source is also placed at one end of the incident sound field.

[0051] Setting up the physics field requires both the acoustic module and the solid mechanics module to be enabled. Sound waves act as a pressure load on the front surface of the model, causing the solid aluminum foam skeleton to vibrate. The vibration of the skeleton then acts as a sound source, radiating sound waves to the transmission sound field on its back surface. This is a typical energy transfer process from sound energy to mechanical vibration energy and then back to sound energy.

[0052] The boundary conditions are set as follows: At the interface between the incident sound field and the solid domain, and at the interface between the solid domain and the transmitted sound field, acoustic structure coupling boundaries need to be set. At the end of the transmitted sound field, a plane wave radiation boundary or a perfectly matched layer is usually set to simulate a free sound field without reflection and prevent sound wave reflection from interfering with the calculation results.

[0053] By solving this coupling field, the acoustic power incident on the model and the acoustic power transmitted to the other side can be obtained respectively. Finally, the sound insulation is defined as the ratio of incident acoustic power to transmitted acoustic power, and expressed in decibels.

[0054] Through the two simulation settings described above, this invention can utilize a unified, high-quality model to conduct a comprehensive quantitative analysis of the acoustic performance of closed-cell aluminum foam in different application scenarios, providing direct and quantifiable simulation data support for the structural design and performance optimization of the material.

[0055] S4. Experimental verification: Process closed-cell aluminum foam samples with parameters consistent with the three-dimensional solid model, obtain experimental data through acoustic impedance tube testing, and compare and verify the results with the acoustic simulation steps.

[0056] In this embodiment, the technical solution provided by the present invention ultimately includes an experimental verification step. The purpose of this step is to physically confirm the accuracy and reliability of the results obtained from the aforementioned series of simulation processes, thereby forming a complete technical closed loop from theoretical calculation to practical verification.

[0057] It should be noted that the value of any simulation method ultimately depends on the degree to which its predictions match the behavior of the real physical world. Therefore, verifying the simulation method itself through a designed physical experiment that strictly corresponds to the simulation conditions is a necessary step in establishing the effectiveness of the method.

[0058] Therefore, the experimental verification steps of this embodiment first require the fabrication of a closed-cell aluminum foam physical sample that is consistent with the key parameters of the three-dimensional solid model. The consistency of parameters is the fundamental premise for ensuring the comparability of simulation and experiment. It includes not only the macroscopic dimensions of the sample, but also its microstructural characteristics, such as the porosity and average pore size range corresponding to the values ​​set in the simulation model, as well as the perforation diameter and open area ratio introduced when conducting sound absorption performance tests.

[0059] During the sample preparation process, considering the relatively soft texture and delicate, easily damaged pore structure of closed-cell aluminum foam, a high-precision special processing method was prioritized to ensure processing accuracy and avoid damage to the sample's microstructure. Specifically, a cylindrical sample matching the inner diameter of the acoustic impedance tube was precisely cut from a large piece of closed-cell aluminum foam using a wire EDM process. This method ensures smooth sample edges and accurate dimensions.

[0060] Furthermore, when it is necessary to prepare perforated samples for sound absorption performance testing, it is preferable to use a high-speed electrical discharge drilling machine to drill holes in the samples. Compared with traditional mechanical drilling, electrical discharge drilling is a non-contact processing method that does not generate cutting force. This can effectively avoid squeezing deformation or tearing of the fragile hole wall structure around the hole, thereby obtaining perforations with accurate hole diameter and regular hole walls, ensuring that the perforation parameters of the physical sample are completely consistent with the settings in the simulation model.

[0061] After obtaining a physical sample that meets the requirements, this embodiment places it into a standard acoustic impedance tube testing system for experimental measurement of acoustic performance. The acoustic impedance tube is a standard device designed according to relevant international standards for the accurate measurement of the acoustic properties of materials. During the test, the sample is tightly installed at a designated position in the pipe, a plane sound wave of known frequency is emitted through a speaker at one end of the pipe, and the sound field information is measured using a microphone array arranged in the pipe.

[0062] Depending on the test configuration, the system can measure the sound absorption coefficient and sound insulation of the material respectively. By processing and analyzing the collected sound pressure signal, the experimental data curve of the physical sample in the corresponding frequency range can be obtained.

[0063] The final step in this embodiment is to plot the simulation result curve calculated in the aforementioned acoustic simulation steps with the experimental data curve obtained through impedance tube testing in this step on the same coordinate system for direct comparison and analysis.

[0064] By comparing the overall trend, peak frequency position, and numerical similarity of the two curves, the effectiveness of the entire simulation method proposed in this invention can be objectively evaluated. If the simulation curve and the experimental curve show good consistency, it proves that the series of technical means adopted in this invention, from the construction of three-dimensional solid models and homogenization optimization to acoustic calculation, are correct and reliable. This also confirms that the simulation method can serve as an effective prediction tool to guide and optimize the acoustic structure design of closed-cell aluminum foam, thereby largely replacing the cumbersome and costly trial-and-error physical experiments in the early research and development.

Claims

1. A method for simulating the acoustic performance of closed-cell aluminum foam based on the Voronoi model, characterized in that, Includes the following steps: Based on the Voronoi principle, a three-dimensional solid model of the closed-cell aluminum foam with adjustable porosity, pore size and wall thickness parameters was constructed. A random point homogenization algorithm is used to homogenize the Voronoi polyhedral structure in the three-dimensional solid model to improve the model quality. The optimized three-dimensional solid model is imported into finite element simulation software to build a simulation model and calculate its sound absorption or sound insulation performance. A closed-cell aluminum foam sample with parameters consistent with the three-dimensional solid model was fabricated, and experimental data was obtained through acoustic impedance tube testing. The results were then compared and verified with those from the acoustic simulation steps.

2. The method of simulating the acoustic performance of a closed-cell aluminum foam based on a Voronoi model according to claim 1, wherein, The model construction specifically involves: bidirectionally offsetting each bisecting facet of the Voronoi polyhedron to form a hole wall with a set wall thickness, thereby constructing the three-dimensional solid model that avoids the problem of wall thickness overlap.

3. The method of simulating the acoustic performance of a closed-cell aluminum foam based on a Voronoi model according to claim 2, wherein, The equations of the two perpendicular bisecting planes after the offset are: ； wherein, , , is the coordinate of any point on the offset vertical bisector plane; , , is the coordinate of the midpoint of the line connecting the two random points before offset; , , is the unit normal vector component of the bisector plane; is the wall thickness of the three-dimensional solid model.

4. The method for simulating the acoustic performance of closed-cell aluminum foam based on the Voronoi model according to claim 1, characterized in that, The random point homogenization algorithm specifically includes: After generating the initial Voronoi polyhedron, the random nucleation points of each polyhedron are adjusted to the centroid position of the polyhedron through multiple iterations until the three-dimensional solid model with uniform aperture distribution is obtained.

5. The method for simulating the acoustic performance of closed-cell aluminum foam based on the Voronoi model according to claim 4, characterized in that, The random point homogenization algorithm further includes: When generating initial nucleation points, the spatial distribution uniformity of the initial nucleation points is improved by setting and constraining the minimum distance between any two points.

6. The method for simulating the acoustic performance of closed-cell aluminum foam based on the Voronoi model according to claim 1, characterized in that, Prior to the acoustic simulation step, the porosity of the three-dimensional solid model is calculated using the following formula. : ； in, The porosity of the three-dimensional solid model; The volume occupied by the skeleton in the three-dimensional solid model; The total volume of the three-dimensional solid model.

7. The method for simulating the acoustic performance of closed-cell aluminum foam based on the Voronoi model according to claim 1, characterized in that, When calculating the sound absorption performance, the acoustic simulation steps are as follows: The three-dimensional solid model is subjected to virtual drilling, and its sound absorption coefficient at different frequencies is calculated in finite element simulation software.

8. The method for simulating the acoustic performance of closed-cell aluminum foam based on the Voronoi model according to claim 1, characterized in that, When calculating the sound insulation performance, the acoustic simulation steps are as follows: The three-dimensional solid model without any perforation was used, and its sound insulation at different frequencies was calculated using finite element simulation software.

9. The method for simulating the acoustic performance of closed-cell aluminum foam based on the Voronoi model according to claim 1, characterized in that, The sample processing in the experimental verification step is specifically completed using wire EDM or high-speed EDM to ensure that the sample parameters are consistent with the parameters of the three-dimensional solid model.

10. The method for simulating the acoustic performance of closed-cell aluminum foam based on the Voronoi model according to claim 1, characterized in that, The model was built in ABAQUS software through its Python script interface, and the acoustic simulation steps were performed in the COMSOL multiphysics simulation platform.

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