Heterogeneous superstructure

Abstract

The application discloses a heterogeneous superstructure, comprising a periodic distribution of three-dimensional composite unit cells, each unit at least containing a topological substructure with different Poisson's ratio characteristics, and the topological substructures are mechanically coupled through three-dimensional gradient surfaces; wherein the topological substructure comprises: a first-level structure composed of regular polygonal cells connected by surface connection structures, which presents a positive Poisson's ratio response of radial expansion when compressed in the plane; a second-level structure composed of concave polygonal cells nested in the first-level structure and connected by surface connection structures, which presents a negative Poisson's ratio response of radial contraction when compressed in the plane; the three-dimensional gradient surface has a curvature continuous transition feature, so that the Poisson's ratio responses of the first-level structure and the second-level structure form a nonlinear superposition, and when the axial compression load reaches a critical threshold, a stiffness gradient jump effect is generated at the cell interface. The internal negative Poisson's ratio area absorbs energy, and the external positive Poisson's ratio area disperses stress, and the two areas work together to improve the stiffness.

Description

Technical Field

[0001] This invention relates to the field of engineering structure technology, and more specifically to a superstructure with stiffness enhancement effect. Background Technology

[0002] In the field of engineering vibration control and energy dissipation, damping technology, as a core means of suppressing structural vibration and absorbing impact energy, is widely used in scenarios such as building seismic resistance, mechanical vibration reduction, vehicle suspension, and precision instrument protection. Traditional passive damping devices mainly rely on the following two types of technologies: Hydraulic dampers: These dissipate energy based on the viscous effect of Newtonian fluids (such as silicone oil), but their linear response characteristics make it difficult to adapt to dynamic load requirements with wide frequency ranges and varying amplitudes, and they are prone to fluid leakage or sealing failure under extreme impacts. Viscoelastic material dampers: These absorb energy using the hysteretic properties of polymer materials, but they are prone to material fatigue under long-term cyclic loading, resulting in insufficient performance stability and difficulty in achieving compatibility with both high-frequency and low-frequency vibrations. In recent years, smart materials (such as magnetorheological fluids and electrorheological fluids) have achieved active control of damping characteristics by regulating fluid viscosity through external magnetic or electric fields. However, such technologies have significant drawbacks: dependence on external energy supply (requiring continuous power or magnetization, resulting in high system complexity and the risk of failure during power outages); response delay and electromagnetic interference (the transmission and execution of external control signals are lagging, making it difficult to meet the real-time control requirements of transient impacts, and electromagnetic interference may affect the operation of precision equipment). Non-Newtonian fluids, due to their unique rheological properties (such as shear thickening or shear thinning effects), offer a new direction for passive adaptive damping technology. However, existing non-Newtonian fluid damping structures still suffer from the following technical bottlenecks: structural design limitations (mostly employing a closed design with a rigid cavity and piston, leading to uneven fluid distribution, local stress concentration, and piston movement easily causing seal failure); lack of self-resetting capability (traditional rigid structures cannot return to their initial shape after load removal, making it difficult to meet long-term stability requirements under cyclic loads); manufacturing process constraints (complex cavity structures are difficult to seal with high precision using conventional processing techniques, limiting the performance of non-Newtonian fluids). To address the aforementioned issues, a novel composite structure is urgently needed. Through the synergistic optimization of materials and geometric design, this structure can overcome the limitations of existing damping technologies and achieve a passive, adaptive, highly reliable, and self-resetting energy dissipation mechanism. Summary of the Invention

[0003] To address the technical problems existing in the background art, the present invention proposes a heterogeneous superstructure comprising periodically distributed three-dimensional composite unit cells, each unit cell containing at least a topological substructure with different Poisson bit properties, wherein the topological substructures are mechanically coupled through a three-dimensional gradient surface.

[0004] The topological substructure includes:

[0005] The first-level structure is composed of regular polygonal unit cells connected by curved surfaces, and exhibits a positive Poisson's ratio response with radial expansion when compressed in the plane.

[0006] The second-level structure, which is a concave polygonal unit cell nested within the first-level structure, is formed by a curved surface connection structure and exhibits a radially contracting negative Poisson's ratio response when compressed in the plane.

[0007] The three-dimensional gradient surface has a continuous curvature transition feature, which makes the Poisson's ratio response of the first-level structure and the second-level structure form a nonlinear superposition. When the axial compressive load reaches the critical threshold, a stiffness gradient jump effect is generated at the unit cell interface.

[0008] Furthermore, the structural parameters include in-plane thickness t, concave angle θ1, convex angle θ2, total height h, total length d1, and total width d2.

[0009] Furthermore, the unit cell is specifically a concave hexagonal structure with an outward convex angle of θ2 and an inward concave angle of θ1 set at d2 / 2 along the Y-axis, so that the concave hexagon is coupled within the regular hexagonal unit cell.

[0010] Furthermore, the three-dimensional gradient surface is composed of four surfaces of equal area connected together to form horizontal and vertical creases.

[0011] Furthermore, during compression, the positive Poisson's ratio region disperses pressure laterally, while the negative Poisson's ratio region triggers a coupling effect after being compacted through lateral creases.

[0012] Furthermore, the parameters are set as follows: θ1 = θ2 = 45°, d1 = d2 = 18 mm, h = 12 mm, and t = 1 mm.

[0013] Furthermore, the angle between the transverse crease and the axial crease is 60°-120°.

[0014] The beneficial effects of this invention are: the internal negative Poisson's ratio region absorbs energy, and the external positive Poisson's ratio region disperses stress, resulting in a synergistic effect that improves stiffness. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] Figure 1 A diagram of a hexagonal honeycomb unit cell structure provided in an embodiment of the present invention;

[0017] Figure 2 The following are front view, side view, and sectional view of a hexagonal honeycomb unit cell provided in the embodiments of the present invention;

[0018] Figure 3 It consists of traditional regular hexagonal unit cells and concave hexagonal unit cells;

[0019] Figure 4 Force-displacement curves of the hexagonal reinforced unit cell structure and the other two unit cells provided in this embodiment of the invention;

[0020] Figure 5 Energy absorption curves of the hexagonal enhanced unit cell structure and the other two unit cells provided in this embodiment of the invention;

[0021] Figure 6 The specific energy absorption curves of the hexagonal enhanced unit cell structure and the other two unit cells provided in the embodiments of the present invention are shown. Detailed Implementation

[0022] Reference Figure 1-6 This invention proposes a heterogeneous superstructure comprising periodically distributed three-dimensional composite unit cells, each unit cell containing at least a topological substructure with different Poisson ratios. These topological substructures are mechanically coupled through a three-dimensional gradient surface. The topological substructure includes: a first-level structure, composed of regular polygonal unit cells connected by a surface structure, exhibiting a radially expanding positive Poisson ratio response under in-plane compression; and a second-level structure, composed of concave polygonal unit cells nested within the first-level structure connected by a surface structure, exhibiting a radially contracting negative Poisson ratio response under in-plane compression. The three-dimensional gradient surface possesses a continuous curvature transition characteristic, causing the Poisson ratio responses of the first-level and second-level structures to form a nonlinear superposition. When the axial compressive load reaches a critical threshold, a stiffness gradient jump effect is generated at the unit cell interface.

[0023] Among them, see Figure 1-2 The three-dimensional surface achieves deformation coupling through transverse and longitudinal creases. The transverse creases guide axial contraction during compression. (See...) Figure 4-6 The longitudinal creases induce lateral contraction, the internal negative Poisson's ratio region absorbs energy, and the external positive Poisson's ratio region disperses stress, which work together to improve stiffness.

[0024] Furthermore, the structural parameters include in-plane thickness t, concave angle θ1, convex angle θ2, total height h, total length d1, and total width d2. See [link / reference] Figure 2 Among them, θ1 and θ2 control the concave and convex curvatures, and the d1 / d2 ratio affects the deformation synergy. Parametric design can be adapted to different load scenarios and optimize stiffness and energy absorption efficiency.

[0025] The unit cell is specifically a concave regular hexagonal structure. The outward convex angle of the unit cell is θ2, and an inward concave angle θ1 is set at d2 / 2 along the Y-axis, so that the concave hexagon is coupled within the regular hexagonal unit cell. See [the diagram]. Figure 3 When θ1=θ2=45°, the concave / convex structure is symmetrically coupled. The symmetrical design can avoid stress concentration and improve structural stability.

[0026] Furthermore, the three-dimensional gradient surface is composed of four surfaces of equal area connected together, forming horizontal and vertical creases. (See...) Figure 1 The design of four curved surfaces with equal areas ensures uniform load distribution, eliminates localized weakened areas, and improves overall load-bearing capacity.

[0027] Furthermore, during compression, the positive Poisson's ratio region disperses pressure laterally, while the negative Poisson's ratio region, after compaction through lateral creases, triggers a coupling effect. See [the relevant documentation]. Figure 1 After the transverse crease is compacted, the axial crease contracts inward, enabling the two-stage deformation mechanism to achieve gradual energy absorption and avoid brittle failure.

[0028] Compared to traditional concave hexagonal structures, this design retains the dominant bending deformation mode and increases material utilization in the out-of-plane thickness direction through a three-dimensional curved surface. The three-dimensional curved surface replaces straight or circular rods, reducing porosity; without increasing mass, material utilization is improved by 20%-30% (see...). Figure 6 (Specific energy absorption curve).

[0029] Furthermore, the parameters are set as follows: θ1 = θ2 = 45°, d1 = d2 = 18 mm, h = 12 mm, t = 1 mm. See [link / reference]. Figure 4 The examples demonstrate that this parameter combination results in the most significant increase in stiffness, and optimizing the parameters makes the stiffness more than three times that of the traditional structure.

[0030] Furthermore, the energy absorption curve shows a linear increasing trend, and the specific energy absorption value is higher than that of traditional regular hexagonal and concave hexagonal unit cells, see... Figure 5 The three-dimensional curved surface co-bearing structure increases the energy absorption rate by 40%, making it suitable for high-dynamic impact scenarios, such as aerospace cushioning components.

[0031] Furthermore, the three-dimensional curved surface design in the out-of-plane thickness direction causes the specific energy absorption value to continuously increase with increasing strain. See Figure 6 Among them, the energy absorption value at 50% strain is 2.5 times that of the traditional structure, achieving high energy density absorption in lightweight design.

[0032] Furthermore, the angle between the transverse crease and the axial crease is 60°-120°. See Figure 1 The crease angle controls the unfolding angle of the three-dimensional curved surface, and the optimization of the angle improves the deformation coordination by 15%-25%.

[0033] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A heterogeneous superstructure, characterized in that, It includes periodically distributed three-dimensional composite unit cells, each containing at least a topological substructure with different Poisson bit properties, the topological substructures forming mechanical coupling through a three-dimensional gradient surface; The topological substructure includes: The first-level structure is composed of regular polygonal unit cells connected by curved surfaces, and exhibits a positive Poisson's ratio response with radial expansion when compressed in the plane. The second-level structure, which is a concave polygonal unit cell nested within the first-level structure, is formed by a curved surface connection structure and exhibits a radially contracting negative Poisson's ratio response when compressed in the plane. The three-dimensional gradient surface has a continuous curvature transition feature, which makes the Poisson's ratio response of the first-level structure and the second-level structure form a nonlinear superposition. When the axial compressive load reaches the critical threshold, a stiffness gradient jump effect is generated at the unit cell interface.

2. The superstructure according to claim 1, characterized in that, The structural parameters include in-plane thickness t, concave angle θ1, convex angle θ2, total height h, total length d1, and total width d2.

3. The superstructure according to claim 1, characterized in that, The unit cell is a concave regular hexagonal structure with an outward convex angle of θ2. An inward concave angle θ1 is set at d2 / 2 along the Y-axis, so that the concave hexagon is coupled within the regular hexagonal unit cell.

4. The superstructure according to claim 1, characterized in that, The three-dimensional gradient surface is composed of four surfaces of equal area connected together, forming horizontal and vertical creases.

5. The superstructure according to claim 4, characterized in that, During compression, the positive Poisson's ratio region disperses pressure laterally, while the negative Poisson's ratio region triggers a coupling effect after being compacted through lateral creases.

6. The superstructure according to claim 2, characterized in that, The parameters are θ1=θ2=45°, d1=d2=18mm, h=12mm, and t=1mm.

7. The superstructure according to claim 1, characterized in that, The angle between the horizontal crease and the axial crease is 60°-120°.

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