Multi-level interpenetrating lattice structure with high energy absorption and high bearing performance

Abstract

The invention relates to the technical field of structural lightweight and structural energy absorption, in particular to a multi-level interpenetrating lattice structure with high energy absorption and high bearing performance, which is composed of a macroscopic hierarchical structure and a microscopic hierarchical structure, the macroscopic hierarchical structure is located inside the microscopic hierarchical structure, and the microscopic hierarchical structure is located inside the macroscopic hierarchical structure. The macroscopic hierarchical structure and the mesoscopic hierarchical structure are two types of three-period minimal curved surface lattice structures with different unit cell sizes. The multi-level interpenetrating lattice structure is formed by combining in a multi-level combination mode, the bearing performance and the energy absorption performance of the whole structure can be improved, and the bearing performance and the energy absorption performance of the multi-level interpenetrating lattice structure are superior to those of a single-level lattice structure.

Description

Technical Field

[0001] This invention relates to the fields of lightweight structure and energy absorption structure, specifically a multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity. Background Technology

[0002] As aerospace, rail transportation, and other transportation equipment evolve towards lightweight, high load-bearing, and high energy absorption, the demand for lightweight, high-strength, and multifunctional integrated new structures is becoming increasingly urgent. Lattice structures, with their high specific strength, excellent energy absorption and vibration reduction performance, and significant lightweight potential, demonstrate significant advantages in transportation equipment design. However, existing lattice structures are mainly based on single-type topological configurations, such as body-centered cubic and face-centered cubic structures. Their mechanical properties are related to their topological configuration and volume fraction, resulting in limited adjustable parameters for mechanical properties. This presents a technical bottleneck in achieving synergistic effects of high energy absorption and high load-bearing capacity.

[0003] Chinese patent application (CN118003715A, A High-Specific-Energy-Absorbing Variable-Density Lattice Structure) discloses a variable-density diamond-shaped lattice structure, which is a gradient lattice structure formed by stacking multiple layers of lattice structures with different densities. The variable-density lattice structure designed by this method exhibits a layer-by-layer collapse failure mode during compression deformation, which can ensure the integrity of the lattice structure and improve its specific energy absorption performance. However, the gradient lattice structure formed by this method has low strength, making it difficult to simultaneously improve load-bearing capacity and energy absorption performance.

[0004] Chinese patent application (CN116432495A, Design method of novel lattice cell combining truss and curved surface) discloses a novel lattice structure design method. This method combines truss and curved surface to form a novel lattice structure, which is used to improve the mechanical performance of the lattice structure. However, due to the discontinuity of the nodal area of ​​the truss, stress concentration is prone to occur, which affects the load-bearing performance of the structure.

[0005] Therefore, achieving a synergistic improvement in the load-bearing capacity and energy absorption capacity of lattice structures has become an urgent problem to be solved. Nature contains numerous biological structures with excellent mechanical properties, such as the multi-scale hierarchical structure in starfish skeletons, which is lightweight, high-strength, and has high energy absorption characteristics. By mimicking the multi-scale hierarchical structure in starfish skeletons and combining lattice structures of different scales to form multi-level interpenetrating lattice structures, it is possible to achieve a synergistic effect of high energy absorption and high load-bearing capacity, among other mechanical properties. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity, while simultaneously improving the load-bearing capacity and energy absorption performance of the lattice structure.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity, comprising a macroscopic hierarchical structure and a mesoscopic hierarchical structure, wherein the macroscopic hierarchical structure is located inside the mesoscopic hierarchical structure, and the macroscopic hierarchical structure and the mesoscopic hierarchical structure are two three-period minimal surface lattice structures with different unit cell sizes.

[0008] Preferably, the macroscopic hierarchical structure is a rod-shaped primitive three-period minimal surface lattice structure, and the microscopic hierarchical structure is a shell-shaped gyroid three-period minimal surface lattice structure.

[0009] Preferably, the ratio of the unit cell size of the macroscopic hierarchical structure to that of the mesoscopic hierarchical structure is 3:1.

[0010] Preferably, the unit cell size of the multi-level interpenetrating lattice structure is 12mm×12mm×12mm, the unit cell size of the macroscopic hierarchical structure is 12mm×12mm×12mm, and the unit cell size of the microscopic hierarchical structure is 4mm×4mm×4mm.

[0011] Preferably, the volume fraction of the multi-level interpenetrating lattice structure is 10% to 30%.

[0012] Preferably, the volume of the macroscopic hierarchical structure accounts for 20% to 80% of the volume of the multi-level interpenetrating lattice structure.

[0013] Preferably, the multi-level interpenetrating lattice structure is integrally formed using additive manufacturing technology.

[0014] Compared with the prior art, the beneficial effects of the present invention are: by combining multiple levels to form a multi-level interpenetrating lattice structure, the load-bearing capacity and energy absorption capacity of the overall structure are improved, and its load-bearing capacity and energy absorption capacity are superior to those of a single-level lattice structure. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of a single cell of the multi-level interpenetrating lattice structure provided by the present invention;

[0017] Figure 2 A top view of a unit cell of the multi-level interpenetrating lattice structure provided by the present invention;

[0018] Figure 3A schematic diagram of a unit cell representing a macroscopic hierarchical structure;

[0019] Figure 4 A schematic diagram of a single cell showing a detailed hierarchical structure;

[0020] Figure 5 A schematic diagram of a multi-level interpenetrating lattice structure formed by a multi-level interpenetrating lattice structure unit cell array.

[0021] Figure 6 A schematic diagram of quasi-static compression deformation of a macroscopic hierarchical rod-shaped primitive three-period minimal surface lattice structure;

[0022] Figure 7 A schematic diagram of the quasi-static compressive deformation of the hierarchical shell-like gyroid three-period minimal surface lattice structure for detailed observation;

[0023] Figure 8 A schematic diagram of quasi-static compressive deformation of a multi-level interpenetrating lattice structure;

[0024] Figure 9 To obtain the stress-strain curves of multi-level interpenetrating lattice structures and single-level lattice structures through quasi-static mechanical compression experiments;

[0025] Figure 10 This is a comparison diagram of energy absorption and compressive strength between a multi-level interpenetrating lattice structure and a single-level lattice structure. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used is for describing particular embodiments only and is not intended to limit the invention.

[0028] Please see Figures 1 to 5 As shown, a multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity includes a macroscopic hierarchical structure and a mesoscopic hierarchical structure. The macroscopic hierarchical structure is located inside the mesoscopic hierarchical structure. The macroscopic hierarchical structure and the mesoscopic hierarchical structure are two three-period minimal surface lattice structures with different unit cell sizes.

[0029] Specifically, the microscopic hierarchical structure adopts a shell-like gyroid three-period minimal surface lattice structure to provide high energy absorption performance, while the macroscopic hierarchical structure adopts a rod-like primitive three-period minimal surface lattice structure to provide high load-bearing capacity. Moreover, the three-period minimal surfaces are smooth and continuous, which can reduce stress concentration.

[0030] Two lattice structures are modeled using implicit function expressions. The expression for the rod-shaped primitive three-periodic minimal surface lattice structure is as follows:

[0031]

[0032] The expression for the shell-like gyroid three-period minimal surface lattice structure is:

[0033]

[0034] In the formula, parameter a controls the size of the lattice unit cell, and parameters t1 and t2 control the volume fraction of the lattice unit cell.

[0035] Furthermore, the ratio of the unit cell size of the multi-macro-level structure to the meso-level structure is 3:1, and the unit cell of the multi-level interpenetrating lattice structure contains 3×3×3 unit cells of the shell-like gyroid three-period minimal surface lattice structure and 1×1×1 unit cell of the rod-like primitive three-period minimal surface lattice structure.

[0036] Furthermore, the unit cell size of the multi-level interpenetrating lattice structure is 12mm×12mm×12mm, the unit cell size of the macroscopic hierarchical structure is 12mm×12mm×12mm, and the unit cell size of the mesoscopic hierarchical structure is 4mm×4mm×4mm. The value of 'a' in the implicit function expression of the rod-shaped primitive three-period minimal surface lattice structure is 12, and the value of 'a' in the implicit function expression of the shell-shaped gyroid three-period minimal surface lattice structure is 4.

[0037] Furthermore, the volume fraction of the multi-level interpenetrating lattice structure is 30%, that is, the sum of the volume fractions of the rod-shaped primitive three-period minimal surface lattice structure and the shell-shaped gyroid three-period minimal surface lattice structure is 30%.

[0038] The volume fraction is defined as the percentage of the volume occupied by the multi-level interpenetrating lattice structure in the 12mm×12mm×12mm cube structure being 30%, that is, the volume of a single cell of the multi-level interpenetrating lattice structure is 518.4mm3, thereby ensuring that the structure has the wall thickness required for forming during the forming process.

[0039] Furthermore, the volume of the macroscopic hierarchical structure accounts for 40% of the volume of the multi-level interpenetrating lattice structure. Therefore, by taking the parameter t1=-1.33, the volume fraction of the rod-shaped primitive three-period minimal surface lattice structure is controlled to be 12%, and its volume is 207.36 mm3; by taking the parameter t2=-0.28, the volume fraction of the shell-shaped gyroid three-period minimal surface lattice structure is controlled to be 18%, and its volume is 311.04 mm3.

[0040] Furthermore, the multi-level interpenetrating lattice structure is integrally formed using additive manufacturing technology. The additive manufacturing technology selected is selective laser melting (SLM), using Ti-6Al-4V alloy powder as the material. The formed multi-level interpenetrating lattice structure is composed of a 2×2×2 unit cell array.

[0041] To further demonstrate the high energy absorption and high load-bearing capacity of the multi-level interpenetrating lattice structure proposed in this invention, the additively manufactured samples were subjected to compression performance tests. The compression rate was kept constant at 2 mm / min at room temperature. The test was repeated twice for the same parameters, and the average value of the results was taken to reduce the error.

[0042] The deformation obtained in the experiment is shown in the figure. Figure 6-8 For single-level lattice structures, the fracture of the rod-shaped primitive three-period minimal surface lattice structure occurs on the vertical rods at the connection points of the structural unit cells, and exhibits 45° shear failure; the shell-shaped gyroid lattice structure undergoes oblique shear band fracture failure, which further develops into an "X" shape.

[0043] For the multi-level interpenetrating lattice structure, no oblique shear band failure was found, resulting in more uniform layered collapse, which enabled the multi-level interpenetrating lattice structure to maintain a high load-bearing capacity even after failure. Figure 9 To obtain the stress-strain curves of multi-level interpenetrating lattice structures and single-level lattice structures through quasi-static mechanical compression experiments, it was found that the load-bearing capacity of the rod-shaped primitive three-period minimal surface lattice structure decreases rapidly after failure, and although it has high load-bearing capacity, it cannot continuously absorb energy; while the shell-shaped gyroid three-period minimal surface lattice structure has a stress plateau after failure, and although it can continuously absorb energy, its load-bearing capacity is weak; the multi-level interpenetrating lattice structure proposed in this invention can maintain a higher stress plateau after failure, and has excellent energy absorption performance while maintaining high strength.

[0044] Figure 10The diagram shows a comparison of the energy absorption and compressive strength of a multi-level interpenetrating lattice structure and a single-level lattice structure. The multi-level interpenetrating lattice structure proposed in this invention has better energy absorption performance and compressive strength than the single-level lattice structure. Specifically, compared with the rod-shaped primitive three-period minimal surface lattice structure and the shell-shaped gyroid three-period minimal surface lattice structure, the energy absorption performance is improved by approximately 719.8% and 66.36%, respectively, and the compressive strength is improved by approximately 245.07% and 61.53%, respectively.

[0045] Furthermore, compared with the sum of the performance of the rod-shaped primitive three-period minimal surface lattice structure and the shell-shaped gyroid three-period minimal surface lattice structure, the multi-level interpenetrating lattice structure proposed in this invention has 59.45% and 9.12% higher energy absorption performance and compressive strength, respectively, and has high energy absorption and high load-bearing performance characteristics.

[0046] The three-period minimal surface lattice structure is not necessarily defined as a rod-shaped primitive or a shell-shaped gyroid three-period minimal surface lattice structure; it can be replaced by other three-period minimal surface lattice structures.

[0047] It should be noted that, as will be apparent to those skilled in the art, the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0048] Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0049] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity, characterized in that: It includes a macroscopic hierarchical structure and a mesoscopic hierarchical structure, wherein the macroscopic hierarchical structure is located inside the mesoscopic hierarchical structure, and the macroscopic hierarchical structure and the mesoscopic hierarchical structure are two three-period minimal surface lattice structures with different unit cell sizes.

2. The multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity according to claim 1, characterized in that, The macroscopic hierarchical structure is a rod-shaped primitive three-period minimal surface lattice structure, and the mesoscopic hierarchical structure is a shell-shaped gyroid three-period minimal surface lattice structure.

3. The multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity according to claim 1, characterized in that, The ratio of the unit cell size of the macroscopic hierarchical structure to that of the mesoscopic hierarchical structure is 3:

1.

4. The multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity according to claim 3, characterized in that, The unit cell size of the multi-level interpenetrating lattice structure is 12mm×12mm×12mm, the unit cell size of the macroscopic hierarchical structure is 12mm×12mm×12mm, and the unit cell size of the mesoscopic hierarchical structure is 4mm×4mm×4mm.

5. A multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity according to claim 1, characterized in that, The volume fraction of the multi-level interpenetrating lattice structure is 10% to 30%.

6. The multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity according to claim 1, characterized in that, The volume of the macroscopic hierarchical structure accounts for 20% to 80% of the volume of the multi-level interpenetrating lattice structure.

7. A multi-level interpenetrating lattice structure with high energy absorption and high load-bearing capacity according to claim 1, characterized in that, The multi-level interpenetrating lattice structure is integrally formed using additive manufacturing technology.

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