A bionic bulkhead filling structure with sound absorption and noise reduction functions and a preparation method thereof

Abstract

This invention discloses a biomimetic bulkhead filling structure with sound absorption and noise reduction functions and its preparation method, belonging to the field of shipbuilding and marine engineering technology. This invention extracts the microscopic hollow structure characteristics of crane feathers and integrates the sound absorption principle of Helmholtz resonators to establish four biomimetic lattice structures. By drawing on the hollow structure characteristics of crane feathers through biomimetic design, a lattice structure base with high mechanical robustness is constructed. At the same time, the sound absorption principle of Helmholtz resonators is integrated to organically combine the resonant sound absorption structure with the biomimetic lattice base. This structure inherits the mechanical advantages of crane feathers in terms of light weight and high mechanical robustness, and also has efficient sound absorption and noise reduction capabilities, meeting the integrated requirements of ship bulkheads for lightweight, high mechanical performance, and wide-band efficient sound absorption and noise reduction.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding and marine engineering technology, and more specifically, to a biomimetic bulkhead filling structure with sound absorption and noise reduction functions and its preparation method. Background Technology

[0002] Ship bulkheads, as core load-bearing and spatial partition structures in the field of shipbuilding and marine engineering, must serve for extended periods in extremely complex marine environments, including those affected by coupled wind, waves, and currents. The continuous dynamic loads generated by the ship's propulsion systems, power systems, and various operational equipment are efficiently transferred to the bulkhead structures through the hull structure. This not only easily leads to mechanical failures such as fatigue damage, buckling deformation, and even fracture in the bulkheads, but also induces broadband noise pollution, severely reducing the structural safety of the ship during navigation. Furthermore, it significantly impacts the living comfort of personnel working inside the bulkheads and substantially interferes with the stable operation and reliability of precision instruments and equipment within them.

[0003] At present, the internal filling structure of ship bulkheads mostly adopts traditional homogeneous metal structure, porous foam material or conventional simple lattice structure. However, all of the above structures have significant performance shortcomings and cannot meet the comprehensive use requirements of modern ship equipment for bulkhead structure lightweighting, high mechanical stability and broadband sound absorption and noise reduction integration. They are also difficult to meet the high performance service requirements of high-end ships, special operation ships and ocean-going ships.

[0004] Specifically, for traditional homogeneous metal-filled structures, the industry currently mostly chooses carbon steel and ordinary aluminum alloys as the base material. While carbon steel possesses excellent static strength and structural load-bearing capacity, its high density significantly increases the overall weight of the hull, increasing the ship's navigation load and thus reducing its effective payload, cruising range, and sailing economy. Although ordinary aluminum alloys have a lower density than carbon steel, their resistance to seawater corrosion and resistance to alternating load fatigue are poor. When operating in the marine environment with salt spray and alternating wave impact for extended periods, they are highly susceptible to stress corrosion cracking and fatigue crack propagation, failing to meet the long-term service requirements of ships for long service life and high reliability.

[0005] In addition, while porous foam materials possess certain sound absorption properties due to their structural characteristics, they suffer from low mechanical strength and poor impact resistance, making them prone to failure under complex mechanical conditions on ships and resulting in a short service life. Conventional metal lattice structures (such as octagonal lattice structures) balance lightweight indicators and basic mechanical properties to a certain extent, effectively reducing the structural weight. However, their micro-configuration design lacks biomimetic optimization, leading to significant local stress concentration under load, making them highly susceptible to overall crush failure and exhibiting poor structural robustness. Furthermore, these structures have not incorporated acoustic resonance sound absorption principles for configuration optimization, resulting in a narrow sound absorption frequency band and low sound absorption efficiency, making them unable to effectively absorb broadband noise generated by ship navigation. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a biomimetic bulkhead filling structure and its preparation method that combine sound absorption and noise reduction functions, thereby meeting the integrated requirements of lightweight, high mechanical performance, and wide-bandwidth, high-efficiency sound absorption and noise reduction for ship bulkheads.

[0007] The specific plan is as follows: The first aspect of this invention provides a method for preparing a biomimetic cabin wall filling structure with sound absorption and noise reduction functions, comprising the following steps: Step 1: Extract the microscopic hollow structure features of the gray crane feathers and integrate the sound absorption principle of the Helmholtz resonator to carry out biomimetic structure design. Based on 3D modeling software, construct a model of the biomimetic lattice structure. The biomimetic lattice structure includes at least one of the following: hollow octagonal truss lattice structure HOS-1, hollow cubic lattice structure HFS-1, hollow octagonal truss lattice structure HOS-0, and hollow cubic lattice structure HFS-0. Step 2: Based on the model of the biomimetic lattice structure established in Step 1, fabricate the biomimetic lattice structure; Step 3: The biomimetic lattice structure prepared in Step 2 is chemically polished to remove residual powder adhering to the surface and internal voids of the structure, and then dried.

[0008] Furthermore, the construction method of the hollow octagonal truss lattice structure HOS-1 is as follows: In 3D modeling software, draw a cube of size a×a×a using a 3D sketch. Then select one vertex of the cube and connect it with three vertices diagonally opposite to that vertex to obtain a tetrahedral sketch. Then, using a circle with a diameter of D as the scanning outline, the scanning operation is performed along the tetrahedral sketch to generate the corresponding cylinder, thus constructing the cylindrical tetrahedron. Next, using a circle with diameter t as the cutting outline, perform solid scan cutting along the tetrahedron sketch to complete the construction of the hollow tetrahedron. The four faces of the hollow tetrahedron are filled with triangular perforated plates to form a closed cavity, thus completing the construction of one-eighth of the cell. Then, three reference planes are created. The three reference planes are perpendicular to each other and all pass through the body center of the cube. They are parallel or perpendicular to the outer surface of the cube. Then, mirroring operations are performed sequentially with the three reference planes as mirror planes to complete the construction of the HOS-1 cell. Finally, the HOS-1 cells are arrayed multiple times along the x, y, and z directions to complete the overall construction of the hollow octagonal truss lattice structure HOS-1.

[0009] Furthermore, the construction method of the hollow cubic lattice structure HFS-1 is as follows: In 3D modeling software, draw a cube of size a×a×a using a 3D sketch. Then select one vertex of the cube and connect it with three vertices diagonally opposite to that vertex to obtain a tetrahedral sketch. Then, using a circle with a diameter of D as the scanning outline, select three straight lines that coincide with a vertex of the tetrahedron and are located on the cube. Combine this with the tetrahedron sketch to perform the scanning operation and generate the corresponding cylinder. In this way, a square cylindrical tetrahedron is constructed. Then, using a circle with diameter t as the cutting contour, perform a sweep cut operation along the sketch of the square cylindrical tetrahedron to complete the construction of the hollow square cylindrical tetrahedron. The four faces of a hollow square cylindrical tetrahedron are filled with triangular perforated plates to form a closed cavity, thus completing the construction of a square one-eighth cell. Create three reference planes, each of which coincides with the three planes of the initial cube, and none of these three planes contain the three lines selected earlier. Perform mirroring operations sequentially using these three reference planes as mirror planes to complete the construction of the HFS-1 cell. Finally, the HFS-1 cells were arrayed multiple times along the x, y, and z directions to complete the overall construction of the hollow cubic lattice structure HFS-1.

[0010] Furthermore, the construction method of the hollow octagonal truss lattice structure HOS-0 is as follows: Based on the HOS-1 cell, a cube with dimensions of 2a×2a×2a was first drawn using 3D sketches, and the HOS-1 cell was then enclosed inside the cube. Then, select the four vertices and the center point of any surface of the cube as the center of the sphere, and cut off the spheres with a diameter of d respectively. Then, with the body center of the cube as the reference, create the first reference axis. The first reference axis is perpendicular to the surface of the cube. Then, perform a circular array operation around the first reference axis after the previous sphere cutting operation. Set the rotation angle to 360° and the array number to 4 to complete the construction of the HOS-0 cell. Finally, the HOS-0 cells are arrayed multiple times along the x, y, and z directions of the spatial rectangular coordinate system to complete the overall construction of the hollow octagonal truss lattice structure HOS-0.

[0011] Furthermore, the construction method of the hollow cubic lattice structure HFS-0 is as follows: Based on the HFS-1 cell, a cube with dimensions of 2a×2a×2a was first drawn using 3D sketches, and the HFS-1 cell was then enclosed inside the cube. Then, select the four vertices and the center point of any surface of the cube as the center of the sphere, and cut off the spheres with a diameter of d respectively. Next, with the center of the cube as the reference, create the second reference axis. The second reference axis is perpendicular to the surface of the cube. Then, perform a circular array operation around the second reference axis after the previous sphere cutting operation. The rotation angle is set to 360° and the array number is set to 4 to complete the construction of the HFS-0 cell. Finally, the HFS-0 cells are arrayed multiple times along the x, y, and z directions of the Cartesian coordinate system to complete the overall construction of the hollow cubic lattice structure HFS-0.

[0012] Furthermore, the outer part of the triangular perforated plate is triangular, and a through hole is formed at the center of the triangle.

[0013] Furthermore, in step two, TC4 titanium alloy is used to print a biomimetic lattice structure based on selective laser melting technology.

[0014] Furthermore, the printing parameters used were: laser power 180 W, scanning rate 800 mm / s, layer thickness 20 μm, and scanning spacing 60 μm.

[0015] Furthermore, the specific process of chemical polishing in step three is as follows: Concentrated nitric acid with a concentration of 15.8 mol / L and concentrated sulfuric acid with a concentration of 18.4 mol / L were mixed at a volume ratio of 1:3 to prepare an etching solution. The biomimetic lattice structure prepared in step two was immersed in the etching solution to remove residual powder adhering to the surface and internal pores of the structure.

[0016] The second aspect of the present invention provides a biomimetic cabin wall filling structure with sound absorption and noise reduction functions, which is prepared by the preparation method of the biomimetic cabin wall filling structure with sound absorption and noise reduction functions according to the first aspect of the present invention.

[0017] The beneficial effects of this invention are as follows: The four biomimetic lattice structures prepared in this invention have superior specific energy absorption performance compared with traditional lattice structures, and can absorb impact energy more efficiently. At the same time, their force-displacement curves fluctuate less, the stress process is stable, they are not prone to sudden collapse failure, and their service life is significantly extended. Compared to the poor mechanical properties of conventional porous structures, the biomimetic lattice structure designed in this invention can maintain good sound absorption and noise reduction capabilities while bearing high loads, and its acoustic performance is significantly better than that of traditional octagonal structures. It achieves integrated and synergistic optimization of mechanical and acoustic performance, and can better meet the actual engineering application needs of ship cabin bulkheads. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the design principle of the present invention.

[0019] Figure 2 This is a flowchart illustrating the structural design of the hollow octagonal truss lattice structure HOS-1 of the present invention.

[0020] Figure 3 This is a flowchart illustrating the structural design of the hollow cubic lattice structure HFS-1 of the present invention.

[0021] Figure 4 This is a flowchart illustrating the structural design of the hollow octagonal truss lattice structure HOS-0 of the present invention.

[0022] Figure 5 This is a flowchart illustrating the structural design of the hollow cubic lattice structure HFS-0 of the present invention.

[0023] Figure 6 This is a comparison diagram of the force-displacement curves of the biomimetic lattice structure of this invention and the traditional octagonal structure.

[0024] Figure 7 for Figure 6 A magnified view of the peak force in the force-displacement curve.

[0025] Figure 8 The diagram shows the energy absorption and fluctuation coefficients of the biomimetic lattice structure of this invention and the traditional octagonal structure.

[0026] Figure 9 This is a graph showing the variation of the sound absorption coefficient of the biomimetic lattice structure of this invention and the traditional octagonal structure with the frequency of the incident sound wave.

[0027] The reference numerals in the appendix of this invention are as follows: 1. Bionic lattice structure; 11. Hollow octagonal truss lattice structure HOS-1; 12. Hollow cubic lattice structure HFS-1; 13. Hollow octagonal truss lattice structure HOS-0; 14. Hollow cubic lattice structure HFS-0; 2. Octagonal body structure; 111. HOS-1 cell; 112. HFS-1 cell; 113. HOS-0 cell; 114. HFS-0 cell; 115. Cylindrical tetrahedron; 116. Hollow tetrahedron; 117. One-eighth cell; 118. Square cylindrical tetrahedron; 119. Hollow square cylindrical tetrahedron; 120. Square one-eighth cell. Detailed Implementation

[0028] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0029] Please see Figure 1 The method for preparing a biomimetic cabin wall filling structure with sound absorption and noise reduction functions disclosed in this embodiment includes the following steps: Step 1: Extract the microscopic hollow structure features of the gray crane feathers and integrate the sound absorption principle of the Helmholtz resonator to carry out biomimetic structure design. Based on 3D modeling software, construct a model of biomimetic lattice structure 1, and at the same time construct a model of traditional octagonal structure 2 as a comparison sample.

[0030] Crane feathers possess both lightweight properties and excellent mechanical robustness. Their microstructure exhibits a unique hollow structure, which allows the hollow rods to disperse stress through elastic deformation when subjected to external loads, optimizing the force transmission path and significantly improving the structure's impact and deformation resistance. Simultaneously, the hollow configuration enables lightweight design, showcasing a balance of rigidity and flexibility in mechanical properties. The Helmholtz resonator, through the resonance effect of the air column within the cavity, can efficiently dissipate sound energy in specific frequency bands through the conversion of acoustic and mechanical energy, exhibiting excellent directional sound absorption performance. This embodiment, through biomimetic design, draws inspiration from the hollow structure of crane feathers to construct a highly mechanically robust lattice structure substrate. Simultaneously, it integrates the sound absorption principle of the Helmholtz resonator, organically combining the resonant sound-absorbing structure with the biomimetic lattice substrate. This allows the structure to inherit the lightweight and highly mechanically robust mechanical advantages of crane feathers while also possessing efficient sound absorption and noise reduction capabilities. Compared to traditional single-function structures, it further achieves an integrated force-sound function that combines structural mechanical load-bearing and sound absorption / noise reduction.

[0031] The biomimetic lattice structure 1 includes at least one of the following: Hollow Octet-truss structure HOS-1 (Hollow Octet-truss structure-1) 11, Hollow Square Structure HFS-1 (Hollow Square Structure-1) 12, Hollow Octet-truss structure HOS-0 (Hollow Octet-truss structure-0) 13, and Hollow Square Structure HFS-0 (Hollow Square Structure-0) 14.

[0032] Please see Figure 2 The construction method of the hollow octagonal truss lattice structure HOS-1 11 is as follows: First, draw a cube of size a×a×a in SolidWorks using 3D sketch. Then, select one vertex of the cube and connect it to three vertices diagonally opposite to that vertex. The distance between any two vertices in these four vertices is equal, thus obtaining a tetrahedral sketch. Then, using a circle with a diameter of D as the scanning outline, the scanning operation is performed along the tetrahedral sketch to generate the corresponding cylinder, thus constructing the cylindrical tetrahedron 115. Next, the "Scan-Cut" command is invoked, and a circle with a diameter of t is used as the cutting outline. The solid is scanned and cut along the tetrahedral sketch, so that the outer edge of each cylindrical rod on the cylindrical tetrahedron 115 forms an arc-shaped notch, thus completing the construction of the hollow tetrahedron 116. Next, select the positions that coincide with the four triangular faces of the tetrahedron sketch and construct four reference planes respectively. Then, on each reference plane, with the tetrahedron sketch as a reference, call the equidistant solid command to generate triangles, and set the equidistant distance to b. Then, draw a circular sketch with a diameter of c at the center of each triangle. Perform an extrusion operation on the generated triangles and circular sketches, and set the extrusion distance to e. Finally, connect the hollow rod of the hollow tetrahedron 116 through four triangular perforated plates to form a closed body, and complete the construction of the eighth cell 117. Then create three reference planes, namely Figure 2 Reference plane 1, reference plane 2 and reference plane 3 are perpendicular to each other and coincide with the outer surface of the cube. Then, mirroring operations are performed sequentially with each of the three reference planes as mirror planes to complete the construction of HOS-1 cell 111. Finally, the HOS-1 cell 111 is arrayed three times along the x, y, and z directions to complete the overall construction of the hollow octagonal truss lattice structure HOS-1 11.

[0033] Please see Figure 3 The construction method of the hollow cubic lattice structure HFS-112 is as follows: In SolidWorks software, draw a cube of size a×a×a using 3D sketching. Then select one vertex of the cube and connect it to three vertices diagonally opposite to that vertex. The distance between any two vertices in these four vertices is equal, thus obtaining a tetrahedral sketch. Then, using a circle with a diameter of D as the scanning outline, select three straight lines that coincide with a vertex of the tetrahedron and are located on the cube. Combine the tetrahedron sketch with the scanning operation to generate the corresponding cylinder, thereby constructing the square cylindrical tetrahedron 118. Then, using a circle with a diameter of t as the cutting outline, a scanning cutting operation is performed along the sketch of the square cylindrical tetrahedron 118, so that an arc-shaped notch is formed on the outer edge of each cylindrical rod on the square cylindrical tetrahedron 118, thus completing the construction of the hollow square cylindrical tetrahedron 119. Next, select the positions that coincide with the four triangular faces of the tetrahedral sketch, and construct four reference planes respectively. Then, on each reference plane, with the tetrahedral sketch as a reference, call the equidistant solid command to generate triangles, and set the equidistant distance to b. Then, draw a circular sketch with a diameter of c at the center of each triangle. Perform an extrusion operation on the generated triangles and circular sketches, and set the extrusion distance to e. Finally, connect the hollow rod of the hollow square cylindrical tetrahedron 119 through four triangular perforated plates to form a closed body, and complete the construction of the square one-eighth cell 120. Then create three more reference planes, namely Figure 3 Reference plane 1, reference plane 2 and reference plane 3 are selected. Each reference plane coincides with the three planes of the initial cube, and none of the three planes contain the three lines selected earlier. Then, the "mirror" command is called to perform the mirror operation in sequence with the three reference planes as mirror planes to complete the construction of HFS-1 cell 112. Finally, the HFS-1 cell 112 was arrayed three times along the x, y, and z directions to complete the overall construction of the hollow cubic lattice structure HFS-1 12.

[0034] Please see Figure 4 The construction method of the hollow octagonal truss lattice structure HOS-013 is as follows: The construction of the hollow octagonal truss lattice structure HOS-0 13 is based on HOS-1 cell 111. Specifically, based on HOS-1 cell 111, a cube with a size of 2a×2a×2a is first drawn through 3D sketch, and HOS-1 cell 111 is wrapped inside the cube. Then, select the four vertices and the center point of any surface of the cube as the center of the sphere, and cut off the spheres with a diameter of d respectively. Then, with the body center of the cube as the reference, create the first reference axis. The first reference axis is perpendicular to the surface of the cube. Then, perform a circular array operation around the first reference axis on the aforementioned sphere cutting operation. The rotation angle is set to 360° and the array number is set to 4 to complete the construction of HOS-0 cell 113. Finally, the HOS-0 cell 113 is arrayed three times along the x, y, and z directions of the spatial rectangular coordinate system to complete the overall construction of the hollow octagonal truss lattice structure HOS-0 13.

[0035] Please see Figure 5 The construction method of the hollow cubic lattice structure HFS-014 is as follows: The construction of the hollow cubic lattice structure HFS-0 14 is based on HFS-1 cell 112. Specifically, a cube with dimensions of 2a×2a×2a is first drawn using a 3D sketch, and the HFS-1 cell 112 is then enclosed inside the cube. Then, select the four vertices and the center point of any surface of the cube as the center of the sphere, and cut off the spheres with a diameter of d respectively. Then, with the body center of the cube as the reference, create the second reference axis. The second reference axis is perpendicular to the surface of the cube. Then, perform a circular array operation around the second reference axis on the aforementioned sphere cutting operation. The rotation angle is set to 360° and the array number is set to 4 to complete the construction of HFS-0 cell 114. Finally, the HFS-0 cell 114 is arrayed three times along the x, y, and z directions of the spatial rectangular coordinate system to complete the overall construction of the hollow cubic lattice structure HFS-0 14.

[0036] Traditional octagonal structure 2, such as Figure 1 As shown, its cell structure differs from that of HOS-1 cell 111 in that each cylinder on its tetrahedron is solid, and the cylinder rods on each face of the tetrahedron are connected by a closed triangular plate to form a closed body.

[0037] The unified specifications of the above five structures are as follows: the unit cell size of all structures is 7×7×7 mm, the rod diameter D is 1.5 mm, the hollow circle diameter t is 0.8 mm, the hole diameter c of the perforated plate is 0.6 mm, and the plate thickness e is 0.3 mm; among them, the rod diameter of the octagonal structure 2 is consistent with the four cell structures of the biomimetic lattice structure 1, which is 1.5 mm.

[0038] Step 2: Based on the models of the biomimetic lattice structure 1 and the traditional octagonal structure 2 established in Step 1, prepare the biomimetic lattice structure 1 and the octagonal structure 2. The biomimetic lattice structure 1 can be used as the filling structure of the bulkhead.

[0039] Specifically, the five structural models designed in step one were converted into STL format files, imported into Magics software for preprocessing, and structural samples made of TC4 titanium alloy were prepared based on selective laser melting technology and using TC4 titanium alloy material.

[0040] The fabrication was carried out using a laser powder bed fusion printing system. The printing parameters were set as follows: laser power 180W, scanning rate 800mm / s, layer thickness 20μm, and scanning spacing 60μm. This parameter strategy has been verified to print a dot matrix structure with an accuracy of 0.1mm.

[0041] TC4 titanium alloy, as a typical high-performance structural metal material, has low density, high specific strength, excellent seawater corrosion resistance and fatigue damage resistance. It can perfectly meet the service requirements of extreme marine environments. Using it as the core substrate of lattice-filled structures can give full play to the performance advantages of the material itself and make up for the inherent defects of traditional metal substrates.

[0042] Step 3: Chemically polish the biomimetic lattice structure 1 and octagonal structure 2 prepared in Step 2 to remove residual powder adhering to the surface and internal voids of the structure, and then dry them to complete the preparation of five samples.

[0043] The specific process of chemical polishing is as follows: Concentrated nitric acid (HNO3) with a concentration of 15.8 mol / L and concentrated sulfuric acid (H2SO4) with a concentration of 18.4 mol / L were mixed at a volume ratio of 1:3 to prepare an etching solution. The biomimetic lattice structure 1 and octagonal structure 2 prepared in step 2 were immersed in the etching solution for 45 seconds to remove residual powder adhering to the surface and internal voids of the structure.

[0044] After the above five types of samples were dried, quasi-static compression mechanical properties and acoustic sound absorption properties were tested on each group of samples. The mechanical and acoustic performance indicators of each sample were tested and summarized.

[0045] A universal testing machine with a range of 300 kN was used to test the dried samples at a compression rate of 2 mm / min to ensure they met the requirements of a quasi-static compression test. Each test was performed three times to minimize experimental error. Sound absorption was tested using a BSWA SW series impedance tube within the range of 1000-6300 Hz.

[0046] Please see Figure 6 and Figure 7 ,from Figure 6 and Figure 7 The mechanical curves show that the initial peak load of the traditional octagonal structure 2 is 124.75 kN, while the initial peak loads that the hollow octagonal truss lattice structures HOS-1 11 and HOS-0 13 can withstand are 123.45 kN and 118.33 kN, respectively, which are 1% and 5% lower than those of the traditional octagonal structure 2. The initial peak loads of the hollow cubic lattice structures HFS-1 12 and HFS-0 14 are 129.62 kN and 131.42 kN, respectively, which are 4% and 5% higher than those of the traditional octagonal structure 2. These data indicate that the biomimetic lattice structure 1 designed in this invention has a bearing capacity comparable to that of the traditional octagonal structure 2 in terms of initial peak load, and can meet the application requirements of traditional structures in the field of mechanical bearing.

[0047] To characterize the mechanical stability and energy absorption efficiency of a structure under load, a fluctuation coefficient is introduced: ; The mechanical robustness of surface structures, among which , and These represent the maximum force, minimum force, and average force under strains ranging from 0.1 to 0.5, respectively.

[0048] Please see Figure 8 Under a strain of 0.5, the specific energy absorption of the traditional octagonal structure 2 is 31.82 J / g, while the specific energy absorption of the four biomimetic lattice structures 1 of the present invention is 58.91 J / g, 61.82 J / g, 56.88 J / g, and 58.29 J / g, respectively. The specific energy absorption of the four biomimetic lattice structures 1 of the present invention is increased by 85.13%, 94.28%, 78.75%, and 83.18% compared with the traditional octagonal structure 2, respectively. In terms of fluctuation coefficient, the fluctuation coefficient of the traditional octagonal structure 2 is 1.14, while the fluctuation coefficients of the four biomimetic lattice structures 1 of the present invention are 0.44, 0.32, 0.47, and 0.42, respectively. The fluctuation coefficients of the four biomimetic lattice structures 1 of the present invention are reduced by 61.40%, 71.93%, 58.77%, and 63.16% compared with the traditional octagonal structure 2, respectively. Among them, the biomimetic lattice structure 1 with the best fluctuation coefficient is reduced by 71.93% compared with the traditional structure. The above data fully demonstrate that the energy absorption efficiency of the biomimetic lattice structure 1 designed in this invention is significantly better than that of the traditional octagonal structure 2, and its mechanical stability under load is greatly improved, making it more suitable for practical engineering structural applications.

[0049] Please see Figure 8 The highest sound absorption coefficient of the traditional octagonal structure 2 is only about 0.6, while the biomimetic lattice structure 1 of the present invention can achieve a sound absorption coefficient of 1 at a specific frequency, thus achieving a perfect sound absorption effect. Within the frequency range of 1000–6300 Hz, the acoustic performance parameters of each biomimetic lattice structure 1 and the traditional octagonal structure 2 are as follows: the average sound absorption coefficient of the hollow cubic lattice structure HFS-0 14 is 0.59, and the half-absorption bandwidth is 3020 Hz; the average sound absorption coefficient of the hollow cubic lattice structure HFS-1 12 is 0.60, and the half-absorption bandwidth is 3277.5 Hz; the average sound absorption coefficient of the hollow octagonal truss lattice structure HOS-0 13 is 0.65, and the half-absorption bandwidth is 5187.5 Hz; the average sound absorption coefficient of the hollow octagonal truss lattice structure HOS-1 11 is 0.63, and the half-absorption bandwidth is 5062.5 Hz; while the average sound absorption coefficient of the traditional octagonal structure 2 is only 0.33, and the half-absorption bandwidth is 1032.5 Hz.

[0050] The above data shows that the biomimetic lattice structure 1 designed in this invention significantly improves acoustic performance compared to the traditional octagonal structure 2, successfully achieving a wide-frequency sound absorption effect. Among them, the hollow octagonal truss lattice structure HOS-0 13 exhibits the most outstanding acoustic performance optimization effect, with its average sound absorption coefficient increasing by 97.0% and its effective sound absorption range increasing by 402.42% compared to the traditional structure. In summary, the biomimetic lattice structure 1 of this invention successfully achieves integrated design of force and acoustic performance, possessing excellent mechanical load-bearing capacity, energy absorption performance, and efficient sound absorption and noise reduction capabilities, which can meet the dual requirements of structural mechanical performance and acoustic performance in engineering applications.

[0051] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a bionic bulkhead filling structure with sound absorption and noise reduction functions, characterized in that, Includes the following steps: Step 1: Extract the microscopic hollow structure features of the gray crane feathers and integrate the sound absorption principle of the Helmholtz resonator to carry out biomimetic structure design. Based on the three-dimensional modeling software, construct the model of the biomimetic lattice structure (1). The biomimetic lattice structure (1) includes at least one of the following: hollow octagonal truss lattice structure HOS-1 (11), hollow cubic lattice structure HFS-1 (12), hollow octagonal truss lattice structure HOS-0 (13), and hollow cubic lattice structure HFS-0 (14). Step 2: Based on the model of the biomimetic lattice structure (1) established in Step 1, prepare the biomimetic lattice structure (1). Step 3: Chemically polish the biomimetic lattice structure (1) prepared in Step 2 to remove residual powder adhering to the surface and internal voids of the structure, and then dry it.

2. The method for preparing the bionic bulkhead filling structure with sound absorption and noise reduction functions according to claim 1, characterized in that, The construction method of the hollow octagonal truss lattice structure HOS-1 (11) is as follows: In 3D modeling software, draw a cube of size a×a×a using a 3D sketch. Then select one vertex of the cube and connect it with three vertices diagonally opposite to that vertex to obtain a tetrahedral sketch. Then, using a circle with a diameter of D as the scanning outline, the scanning operation is performed along the tetrahedral sketch to generate the corresponding cylinder, thus constructing the cylindrical tetrahedron (115). Next, using a circle with diameter t as the cutting outline, perform solid scanning cutting along the tetrahedron sketch to complete the construction of the hollow tetrahedron (116); The four faces of the hollow tetrahedron (116) are filled with triangular perforated plates to form a closed cavity, thus completing the construction of the eighth cell (117); Then, three reference planes are created, which are perpendicular to each other and coincide with the outer surface of the cube. Then, mirroring operations are performed sequentially with these three reference planes as mirror planes to complete the construction of the HOS-1 cell (111). Finally, the HOS-1 cell (111) is arrayed multiple times along the x, y, and z directions to complete the overall construction of the hollow octagonal truss lattice structure HOS-1 (11).

3. The method for preparing the biomimetic cabin wall filling structure with sound absorption and noise reduction functions according to claim 1, characterized in that, The construction method of the hollow cubic lattice structure HFS-1 (12) is as follows: In 3D modeling software, draw a cube of size a×a×a using a 3D sketch. Then select one vertex of the cube and connect it with three vertices diagonally opposite to that vertex to obtain a tetrahedral sketch. Then, using a circle with a diameter of D as the scanning outline, select three straight lines that coincide with a vertex of the tetrahedron and are located on the cube. Combined with the tetrahedron sketch, perform the scanning operation to generate the corresponding cylinder, thereby constructing a square cylindrical tetrahedron (118). Then, using a circle with diameter t as the cutting outline, perform a sweep cut operation along the sketch of the square cylindrical tetrahedron (118) to complete the construction of the hollow square cylindrical tetrahedron (119); The four faces of the hollow square cylindrical tetrahedron (119) are filled with triangular perforated plates to form a closed cavity, thus completing the construction of the square one-eighth cell (120); Create three reference planes, each of which coincides with the three planes of the initial cube, and none of these three planes contain the three lines selected earlier. Perform mirroring operations sequentially using these three reference planes as mirror planes to complete the construction of HFS-1 cell (112). Finally, the HFS-1 cell (112) is arrayed multiple times along the x, y, and z directions to complete the overall construction of the hollow cubic lattice structure HFS-1 (12).

4. The method for preparing the biomimetic cabin wall filling structure with sound absorption and noise reduction functions according to claim 2, characterized in that, The construction method of the hollow octagonal truss lattice structure HOS-0 (13) is as follows: Based on the HOS-1 cell (111), a cube with dimensions of 2a×2a×2a is first drawn using 3D sketches, and the HOS-1 cell (111) is enclosed inside the cube. Then, select the four vertices and the center point of any surface of the cube as the center of the sphere, and cut off the spheres with a diameter of d respectively. Then, with the center of the cube as the reference, create the reference axis one. The reference axis one is perpendicular to the surface of the cube. Then, perform a circular array operation around the reference axis one, with the previous sphere cutting operation. The rotation angle is set to 360° and the array number is set to 4 to complete the construction of HOS-0 cell (113). Finally, the HOS-0 cell (113) is arrayed multiple times along the x, y, and z directions of the spatial rectangular coordinate system to complete the overall construction of the hollow octagonal truss lattice structure HOS-0 (13).

5. The method for preparing the biomimetic cabin wall filling structure with sound absorption and noise reduction functions according to claim 3, characterized in that, The construction method of the hollow cubic lattice structure HFS-0 (14) is as follows: Based on the HFS-1 cell (112), a cube with dimensions of 2a×2a×2a is first drawn using 3D sketches, and the HFS-1 cell (112) is enclosed inside the cube. Then, select the four vertices and the center point of any surface of the cube as the center of the sphere, and cut off the spheres with a diameter of d respectively. Then, with the body center of the cube as the reference, create the second reference axis. The second reference axis is perpendicular to the surface of the cube. Then, perform a circular array operation around the second reference axis after the previous sphere cutting operation. The rotation angle is set to 360° and the array number is set to 4 to complete the construction of HFS-0 cell (114). Finally, the HFS-0 cell (114) is arrayed multiple times along the x, y, and z directions of the spatial rectangular coordinate system to complete the overall construction of the hollow cubic lattice structure HFS-0 (14).

6. The method for preparing the biomimetic cabin wall filling structure with sound absorption and noise reduction functions according to claim 2, characterized in that, The triangular perforated plate has a triangular shape on the outside and a through hole in the center of the triangle.

7. The method for preparing the biomimetic cabin wall filling structure with sound absorption and noise reduction functions according to claim 1, characterized in that, In step two, TC4 titanium alloy material is used to print a biomimetic lattice structure based on selective laser melting technology (1).

8. The method for preparing the biomimetic cabin wall filling structure with sound absorption and noise reduction functions according to claim 7, characterized in that, The printing parameters used were: laser power 180 W, scanning rate 800 mm / s, layer thickness 20 μm, and scanning spacing 60 μm.

9. The method for preparing the biomimetic cabin wall filling structure with sound absorption and noise reduction functions according to claim 7, characterized in that, The specific process of chemical polishing in step three is as follows: Concentrated nitric acid with a concentration of 15.8 mol / L and concentrated sulfuric acid with a concentration of 18.4 mol / L were mixed at a volume ratio of 1:3 to prepare an etching solution. The biomimetic lattice structure (1) prepared in step two was immersed in the etching solution to remove residual powder adhering to the surface and internal pores of the structure.

10. A biomimetic bulkhead filling structure with sound absorption and noise reduction functions, characterized in that, The biomimetic cabin wall filling structure with sound absorption and noise reduction functions is prepared according to any one of claims 1 to 9.

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