A novel negative poisson's ratio spider-web dot array energy absorption structure and a design method thereof

Abstract

The present application relates to the technical field of energy-absorbing lattice structure, and particularly relates to a novel negative Poisson's ratio spider-web-like lattice energy-absorbing structure and a design method thereof, which is composed of N three-dimensional negative Poisson's ratio unit structures arranged in a periodic array in a three-dimensional space, the three-dimensional negative Poisson's ratio unit structure is based on a two-dimensional negative Poisson's ratio unit structure minimum representative unit, is formed after rotation transformation and symmetric processing, and finally four structure planes with a preset included angle are constructed. The present application takes natural spider webs as a biomimetic prototype, fuses the abnormal deformation characteristics of the negative Poisson's ratio structure, constructs a lattice unit topology containing multiple types of construction points, defines key geometric parameters such as concave angles and rod diameters, and establishes a relative density calculation model to realize controllable design of the structure parameters.

Description

Technical Field

[0001] This invention relates to the field of energy-absorbing lattice structure technology, specifically to a novel negative Poisson's ratio spiderweb-like energy-absorbing structure and its design method. Background Technology

[0002] Lattice structures possess lightweight, high specific strength, high specific stiffness, and excellent designability, making them promising for applications in aerospace, engineering protection, and transportation equipment. Negative Poisson's ratio metamaterials, unlike traditional materials, exhibit an anomalous mechanical response, exhibiting lateral contraction under compression and lateral expansion under tension. This significantly enhances the structure's impact resistance, energy absorption, shear resistance, and sound insulation and vibration reduction performance, providing new insights for the design of high-performance engineering structures.

[0003] Currently, most spiderweb-like lattice structures focus on two-dimensional planar configurations, with limited research on three-dimensional spatial structure design. Furthermore, the synergistic mechanism between three-dimensional spiderweb-like structures and the negative Poisson's ratio effect remains unclear, making it difficult to achieve synergistic improvement in mechanical performance and failing to meet the usage requirements under complex load conditions.

[0004] In view of this, the inventors of this case conducted in-depth research on the above-mentioned problems, which led to the creation of this case. Summary of the Invention

[0005] The purpose of this invention is to provide a novel negative Poisson's ratio spiderweb-like energy-absorbing structure, which can effectively reduce stress concentration in key parts of the structure and improve the uniformity of load transfer. At the same time, by utilizing the characteristics of compressive contraction and controllable deformation of the negative Poisson's ratio structure, the impact resistance and energy absorption efficiency of the structure are significantly improved, thereby enhancing the overall structural safety and reliability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A novel negative Poisson's ratio spiderweb-like energy-absorbing structure is composed of N three-dimensional negative Poisson's ratio unit cells arranged in a periodic array in three-dimensional space. Each three-dimensional negative Poisson's ratio unit cell is formed based on the smallest representative unit of a two-dimensional negative Poisson's ratio unit cell through rotation and symmetry processing, ultimately constructing four structural planes with predetermined angles between them. Each three-dimensional negative Poisson's ratio unit cell includes concave hexagonal structures and triangular and / or polygonal structures, with the triangular and / or polygonal structures embedded within the concave hexagonal structures. The concave points of two adjacent three-dimensional negative Poisson's ratio unit cells in the X-axis direction are fixedly connected by pillars. The negative Poisson's ratio spiderweb-like energy-absorbing structure is composed of any m × n three-dimensional negative Poisson's ratio unit cells, where m and n are both positive integers.

[0007] As a preferred embodiment of the present invention, the preset included angle between each adjacent structural plane is 90°, and the four structural planes are arranged perpendicular to each other in pairs.

[0008] In a preferred embodiment of the present invention, the cross-section of the support column is one of trapezoidal, I-shaped, channel-shaped, rectangular, circular, rhomboid, or regular polygonal.

[0009] In a preferred embodiment of the present invention, the number of struts constituting the three-dimensional negative Poisson's ratio unit cell structure is 76, and the number of pillars is 6.

[0010] As a preferred embodiment of the present invention, the parameters of the three-dimensional negative Poisson's ratio unit cell structure include: the length of the support rod in the X-axis direction. L Y-axis height H The diameter of the support column D concave angle in the X-axis direction α The length from the end point of the X-axis support rod to the intersection point where it is recessed into the support column. R The indentation distance of the intersection point of the recessed support relative to the vertex of the regular hexagon connected to the recessed support. d and total cell length S The three-dimensional negative Poisson's ratio unit cell structure also includes a geometric parameter W characterizing the side length of the internal regular hexagons, and the structural parameters satisfy a matching relationship: ; .

[0011] Another objective of this invention is to provide a novel design method for a negative Poisson's ratio spiderweb-like energy-absorbing structure, which achieves the technical effects of strong adaptability to additive manufacturing processes, stable negative Poisson's ratio characteristics, high buffering energy absorption efficiency, and excellent lightweight structure.

[0012] A novel design method for a negative Poisson's ratio spiderweb-like lattice energy-absorbing structure includes the following steps: S1. Based on the improvement of two-dimensional concave honeycomb lattice unit cell structure and the principle of hybrid unit cell, an innovative three-dimensional negative Poisson's ratio unit cell structure is designed to meet the process constraints of additive manufacturing. S2. Define the geometric parameters and their range of values ​​for the three-dimensional negative Poisson's ratio unit cell structure, and establish the limiting relationships and matching rules between the geometric parameters; S3. Based on the finite element mesh node unit information, the three-dimensional negative Poisson's ratio unit cell structure is filled into the ring structure and arranged in an array to generate a three-dimensional negative Poisson's ratio spider web lattice energy-absorbing structure suitable for finite element analysis; S4. Convergence verification of finite element analysis parameters for negative Poisson's ratio simulated spider web lattice energy-absorbing structures; S5. Generate an arithmetic sequence within the range of geometric parameters, conduct single-factor analysis, and determine the optimal parameters affecting the buffer energy absorption performance; S6. Perform multi-objective optimization on the basic optimization parameters to obtain the optimal combination of geometric parameters.

[0013] As a preferred embodiment of the present invention, the three-dimensional negative Poisson's ratio unit cell structure is formed by constructing the smallest representative unit of negative Poisson's ratio, and then performing rotational transformation and symmetry processing to form a unit cell configuration with four preset included angle structural planes.

[0014] In a preferred embodiment of the present invention, the geometric parameters include the length of the support rod in the X-axis direction. L Y-axis height H The diameter of the support column D concave angle in the X-axis direction α The length from the end point of the X-axis support rod to the intersection point where it is recessed into the support column. R The indentation distance of the intersection point of the recessed support relative to the vertex of the regular hexagon connected to the recessed support. d and total cell length S The three-dimensional negative Poisson's ratio unit cell structure also includes a geometric parameter W characterizing the side length of the internal regular hexagons, and the structural parameters satisfy a matching relationship: ; .

[0015] In a preferred embodiment of the present invention, the three-dimensional negative Poisson's ratio unit cell structure is arranged in an m×n periodic array, where m and n are both positive integers.

[0016] By adopting the aforementioned design scheme, the beneficial effects of this invention are: using natural spider webs as biomimetic prototypes, integrating the anomalous deformation characteristics of negative Poisson's ratio structures, constructing a lattice unit cell topology containing multiple types of construction points, defining key geometric parameters such as concave angles and rod diameters, and establishing a relative density calculation model, thereby achieving controllable design of structural parameters. Attached Figure Description

[0017] Figure 1 This invention relates to the configuration evolution of negative Poisson's ratio in a spider web-like honeycomb structure. Figure 2 These are all the construction points of the NPS lattice unit cell of this invention; Figure 3 This is the structural topology of the NPS lattice unit cell of the present invention; Figure 4 This is the geometric representation of the structural topology in this invention; Figure 5 Structural design for inventing NPS; Figure 6 This is a schematic diagram of the structure of a power battery system in which the present invention is applied; Figure 7 This is a simplified model diagram of the battery of the present invention; Figure 8The present invention is applied to the geometric model of the protective plate structure, wherein a) is the three-dimensional model of the protective plate, b) is the front view of the protective plate, and c) is a partial enlarged view of the NPS structure. Detailed Implementation

[0018] 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.

[0019] Reference Figures 1 to 8 : The simulated honeycomb structure uses regular hexagonal units as its basic components, achieving efficient force transmission and dispersion based on a multi-unit collaborative load-bearing mechanism. When a vertical load is applied to the top of the structure, the load is uniformly transmitted to the surrounding units and the bottom support system through the hexagonal boundary surfaces in the form of multi-directional components, such as horizontal and oblique components. The geometric characteristics of the regular hexagon allow it to transform concentrated loads into multi-directional dispersed forces, effectively avoiding the generation of local stress concentration. Thanks to this force dispersion and collaborative load-bearing effect, this structure ensures load-bearing capacity and deformation resistance while also possessing lightweight advantages. It is widely used in engineering fields with dual requirements for lightweighting and load-bearing performance, such as honeycomb sandwich structures in the aerospace industry.

[0020] Negative Poisson's ratio structures exhibit the mechanical property of opposite lateral and vertical deformation. Under vertical pressure, the structure undergoes inward contraction in the horizontal direction. From a mechanical perspective, under vertical loads, the structural units' oblique or specially constructed components undergo relative movement, causing horizontal contraction deformation during vertical compression. This unique deformation characteristic endows the structure with excellent energy absorption and impact resistance, while also maintaining overall stability during deformation, reducing localized damage caused by uncoordinated lateral deformation. It has potential applications in impact protection and other engineering scenarios.

[0021] This embodiment provides a novel negative Poisson's ratio (NPS) spiderweb-like lattice structure. Based on the spiderweb-like honeycomb design concept, it integrates the mechanical properties of traditional two-dimensional and three-dimensional negative Poisson's ratio structures, achieving synergistic enhancement of biomimetic configuration and negative Poisson's ratio effect. It possesses excellent buffering, energy absorption, impact resistance, and lightweight performance. This embodiment can be widely applied to various buffering, energy absorption, and protection scenarios, including but not limited to new energy vehicle battery packs, footwear and textile products, and other engineering structures and equipment with energy absorption, impact resistance, and lightweight requirements.

[0022] like Figure 1As shown, the spiderweb-like honeycomb structure with negative Poisson's ratio integrates the multi-node force transmission of a spiderweb, the modular synergy of a honeycomb, and the anomalous deformation characteristics of negative Poisson's ratio. The spiderweb-like biomimetic design is manifested in the complex nested connection of triangles or polygons within the structure, increasing the number of nodes and force transmission paths; the modularity of the honeycomb ensures the structure's modularity and scalability. When a vertical load is applied, the load is transmitted through multiple paths in a spiderweb-like manner. With the help of the negative Poisson's ratio units, the structure undergoes inward deformation in the horizontal direction during vertical compression. This multi-mechanism integrated structure, through the multi-path force dispersion effect of the spiderweb structure, the energy absorption and deformation regulation characteristics of negative Poisson's ratio, and the synergistic load-bearing effect of the honeycomb units, optimizes the force transmission efficiency and the overall mechanical performance of the structure. It has application potential in engineering fields requiring high energy absorption and high stability, such as protective structures and vibration damping devices.

[0023] Specifically, a novel negative Poisson's ratio spiderweb-like energy-absorbing structure is composed of N three-dimensional negative Poisson's ratio unit cells arranged in a periodic array in three-dimensional space. The three-dimensional negative Poisson's ratio unit cells are formed based on the smallest representative unit of a two-dimensional negative Poisson's ratio unit cell after rotational transformation and symmetry processing, ultimately constructing four structural planes with predetermined angles between them. Specifically, the angle between any two adjacent two-dimensional negative Poisson's ratio unit cells is 90°.

[0024] As a preferred embodiment of the present invention, the three-dimensional negative Poisson's ratio unit cell structure includes a concave hexagonal structure and triangular and / or polygonal structures, wherein the triangular and / or polygonal structures are embedded inside the concave hexagonal structure.

[0025] In a preferred embodiment of the present invention, the concave points of two adjacent three-dimensional negative Poisson's ratio unit cells in the X-axis direction are fixedly connected by a support column. The negative Poisson's ratio spiderweb-like energy-absorbing structure is composed of any m×n three-dimensional negative Poisson's ratio unit cells, where m and n are both positive integers.

[0026] This embodiment also proposes a novel design method for a negative Poisson's ratio spiderweb-like energy-absorbing structure, which can achieve the technical effects of strong adaptability to additive manufacturing processes, stable negative Poisson's ratio characteristics, high buffer energy absorption efficiency, and excellent lightweight structure.

[0027] A novel design method for a negative Poisson's ratio spiderweb-like lattice energy-absorbing structure includes the following steps: S1. Based on the improvement of two-dimensional concave honeycomb lattice unit cell structure and the principle of hybrid unit cell, an innovative three-dimensional negative Poisson's ratio unit cell structure is designed to meet the process constraints of additive manufacturing. S2. Define the geometric parameters and their range of values ​​for the three-dimensional negative Poisson's ratio unit cell structure, and establish the limiting relationships and matching rules between the geometric parameters; S3. Based on the finite element mesh node unit information, the three-dimensional negative Poisson's ratio unit cell structure is filled into the ring structure and arranged in an array to generate a three-dimensional negative Poisson's ratio spider web lattice energy-absorbing structure suitable for finite element analysis; S4. Convergence verification of finite element analysis parameters for negative Poisson's ratio simulated spider web lattice energy-absorbing structures; S5. Generate an arithmetic sequence within the range of geometric parameters, conduct single-factor analysis, and determine the optimal parameters affecting the buffer energy absorption performance; S6. Perform multi-objective optimization on the basic optimization parameters to obtain the optimal combination of geometric parameters.

[0028] Typically, the unit cell of a lattice structure has a side length of... L The design is carried out within the cubic envelope space. Therefore, the NPS lattice unit cell is also designed within the cubic envelope space.

[0029] For this NPS lattice unit cell, four types of construction points were designed, totaling 36, such as... Figure 2 As shown: 1) Construction points of the 8 cube vertices (black); 2) Construction points of the 24 cube faces (red); 3) Construction points inside the two cubes (blue); 4) Construction points on the outside of the 6 cubes (pink).

[0030] like Figure 3 As shown, connecting the construction points forms the structural topology of an NPS lattice unit cell: 1) Connect the construction points on the 24 cube faces to form 24 support rods (blue); 2) Connect the construction points on the 8 vertices of the cube to the construction points on the 24 faces of the cube to form 36 supports (purple). 3) Connect the two internal structural points to the nearest surface structural points to form 16 support rods (green, some not shown); 4) Connect the two internal structural points to the two nearest external structural points to form two pillars (green); connect the remaining four external structural points to the nearest surface structural points to form pillars (green).

[0031] The resulting structural topology has 76 struts on the envelope space surface and 6 pillars inside the envelope space.

[0032] like Figure 4 and Figure 5 As shown, the topology of an NPS lattice unit cell structure can be characterized by three independent geometric parameters: ① Length of the outer envelope (using symbols) L express); ② Deformation coefficient (using symbols) α express); ③ Unit cell diameter (using symbols) D express).

[0033] This structure is built based on a rotationally symmetric construction method using two-dimensional negative Poisson's ratio elements. It generates four structural planes at specific angles (90° in this embodiment) and introduces two key construction points at the inner and outer boundaries of the envelope space, thereby completing the topology optimization of the unit cell. Subsequently, a complete lattice structure is constructed by periodically arranging the unit cells in three-dimensional space. Figure 5 The spatial connection methods of each component are shown in detail, revealing the intrinsic mechanism by which the structure achieves a negative Poisson's ratio effect while maintaining its lightweight characteristics.

[0034] The design parameter of the unit cell is the length of the horizontal bar. L Vertical height H rod diameter D Concave angle α And the length from the end of the horizontal support to the intersection of the recessed support. R The indentation distance of the intersection point of the concave support relative to the vertex of the regular hexagon connected to the concave support. d Total length of unit cell S These parameters characterize the displacement properties of the three-dimensional concave unit cell structure. Another geometric parameter represents the side length of the internal regular hexagons. W It can be derived from the following formula Derivation. Therefore, based on the feasibility of unit cell design, the parameter design has the following limiting relationship: ; .

[0035] Three parameters (rod diameter) D Concave angle α Distance from the indentation R All three studies constructed a scientifically sound parameter space from the perspectives of forming constraints, mechanical functionality, and response adjustability. Through system performance analysis under parameter combinations, the study not only revealed the mechanism by which geometric variables affect the structure's negative Poisson's ratio behavior and energy absorption capacity, but also provided theoretical basis and data support for subsequent multi-objective structural optimization and high-performance lattice unit design.

[0036] This embodiment uses the power battery system structure of a typical electric bus as an example to apply this structure to a power battery. Figure 6As can be seen, a typical automotive power battery pack system consists of an upper protective plate, battery modules, a bottom protective plate, and crossbeams. The battery modules are located between the floor and the protective plate, with a gap between their top and the floor to address the risk of battery module intrusion; the power battery pack has external dimensions of 1060mm × 630mm × 240mm.

[0037] After simplifying components such as the cooling system, its basic configuration is as follows: Figure 7 As shown. The battery module contains 48 lithium-ion batteries. Considering the arrangement of cooling pipes, the 48 battery cells are arranged in parallel into three groups of 16, with a spacing of 3mm between groups and a spacing of 1mm between cells within a group.

[0038] The optimal parameters for the NPS unit cell structure can be obtained through analysis and experimentation. This protective plate employs a double-layer arrangement, and its structure consists of three parts: an upper panel, a lower panel, and a negative Poisson's ratio core layer. Its structural parameters are as follows: Figure 8 As shown. The negative Poisson ratio protective plate has a length L=923.0mm, a width W=412.11mm, a top and bottom panel thickness T=1.0mm, and a total height H=22.0mm. The negative Poisson ratio protective plate is made of 316L stainless steel, while the water-cooling plate and battery module shell are made of Alu3003 aluminum alloy. According to the newly added bottom impact test requirements of the power battery pack in the national standard GB38031-2025 "Safety Requirements for Power Batteries for Electric Vehicles", the impact analysis of the water-cooling plate shows that the NPS structure has the best impact resistance. With a 44% decrease in overall mass, its maximum equivalent strain is the lowest at only 0.010, which is 78% lower than the 0.046 of the BRAS structure. The NPS structure significantly improves the load distribution capability, effectively alleviates stress concentration, and exhibits excellent impact resistance.

[0039] By adopting the aforementioned design scheme, the beneficial effects of this invention are: using natural spider webs as biomimetic prototypes, integrating the anomalous deformation characteristics of negative Poisson's ratio structures, constructing a lattice unit cell topology containing multiple types of construction points, defining key geometric parameters such as concave angles and rod diameters, and establishing a relative density calculation model, thereby achieving controllable design of structural parameters.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A novel negative Poisson's ratio spiderweb-like lattice energy-absorbing structure, characterized in that: The structure is composed of N three-dimensional negative Poisson's ratio unit cells arranged in a periodic array in three-dimensional space. Each three-dimensional negative Poisson's ratio unit cell is based on the smallest representative unit of a two-dimensional negative Poisson's ratio unit cell, formed through rotation and symmetry processing, ultimately constructing four structural planes with predetermined angles between them. Each three-dimensional negative Poisson's ratio unit cell includes concave hexagonal structures and triangular and / or polygonal structures, with the triangular and / or polygonal structures embedded within the concave hexagonal structures. The concave points of two adjacent three-dimensional negative Poisson's ratio unit cells in the X-axis direction are fixedly connected by pillars. The negative Poisson's ratio spiderweb-like lattice energy-absorbing structure is composed of any m × n three-dimensional negative Poisson's ratio unit cells, where m and n are both positive integers.

2. The novel negative Poisson's ratio spiderweb-like lattice energy-absorbing structure according to claim 1, characterized in that: The preset included angle between each adjacent structural plane is 90°, and the four structural planes are arranged perpendicular to each other in pairs.

3. The novel negative Poisson's ratio spiderweb-like lattice energy-absorbing structure according to claim 1, characterized in that: The cross-section of the support column is one of the following: trapezoidal, I-shaped, channel-shaped, rectangular, circular, rhomboid, or regular polygonal.

4. The novel negative Poisson's ratio spiderweb-like lattice energy-absorbing structure according to claim 1, characterized in that: The number of struts constituting the three-dimensional negative Poisson's ratio unit cell structure is 76, and the number of struts is 6.

5. The novel negative Poisson's ratio spiderweb-like lattice energy-absorbing structure according to claim 1, characterized in that: The parameters of the three-dimensional negative Poisson's ratio unit cell structure include: the length of the support rod in the X-axis direction. L Y-axis height H The diameter of the support column D concave angle in the X-axis direction α The length from the end point of the X-axis support rod to the intersection point where it is recessed into the support column. R The indentation distance of the intersection point of the recessed support relative to the vertex of the regular hexagon connected to the recessed support. d and total cell length S The three-dimensional negative Poisson's ratio unit cell structure also includes a geometric parameter W characterizing the side length of the internal regular hexagons, and the structural parameters satisfy a matching relationship: ； 。 6. A design method for a novel negative Poisson's ratio spiderweb-like lattice energy-absorbing structure, characterized in that: Includes the following steps: S1. Based on the improvement of two-dimensional concave honeycomb lattice unit cell structure and the principle of hybrid unit cell, an innovative three-dimensional negative Poisson's ratio unit cell structure is designed to meet the process constraints of additive manufacturing. S2. Define the geometric parameters and their range of values ​​for the three-dimensional negative Poisson's ratio unit cell structure, and establish the limiting relationships and matching rules between the geometric parameters; S3. Based on the finite element mesh node unit information, the three-dimensional negative Poisson's ratio unit cell structure is filled into the ring structure and arranged in an array to generate a three-dimensional negative Poisson's ratio spider web lattice energy-absorbing structure suitable for finite element analysis; S4. Convergence verification of finite element analysis parameters for negative Poisson's ratio simulated spider web lattice energy-absorbing structures; S5. Generate an arithmetic sequence within the range of geometric parameters, conduct single-factor analysis, and determine the optimal parameters affecting the buffer energy absorption performance; S6. Perform multi-objective optimization on the basic optimization parameters to obtain the optimal combination of geometric parameters.

7. The design method of a novel negative Poisson's ratio spiderweb-like lattice energy-absorbing structure according to claim 6, characterized in that: The three-dimensional negative Poisson's ratio unit cell structure is formed by constructing the smallest representative unit of the two-dimensional negative Poisson's ratio unit cell structure, and then performing rotational transformation and symmetry processing to form a unit cell configuration with four preset included angle structural planes.

8. The design method of a novel negative Poisson's ratio spiderweb-like lattice energy-absorbing structure according to claim 6, characterized in that: The geometric parameters include the length of the support rod in the X-axis direction. L Y-axis height H , diameter of the support column D concave angle in the X-axis direction α The length from the end point of the X-axis support rod to the intersection point where it is recessed into the support column. R The indentation distance of the intersection point of the recessed support relative to the vertex of the regular hexagon connected to the recessed support. d and total cell length S The three-dimensional negative Poisson's ratio unit cell structure also includes a geometric parameter W characterizing the side length of the internal regular hexagons, and the structural parameters satisfy a matching relationship: ； 。 9. The design method of a novel negative Poisson's ratio spiderweb-like lattice energy-absorbing structure according to claim 6, characterized in that: The three-dimensional negative Poisson's ratio unit cell structure is arranged in an m×n periodic array, where m and n are both positive integers.

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