Three-dimensional honeycomb structure based on waveform curved surface nesting and preparation method thereof

Abstract

The invention relates to a three-dimensional honeycomb structure based on waveform curved surface nesting and a preparation method thereof.The three-dimensional honeycomb structure comprises a first waveform curved surface component and a second waveform curved surface component, the first waveform curved surface component and the second waveform curved surface component are both periodic concave-convex curved surfaces extending along the x-y plane, and each period comprises one wave crest and one wave trough; in the two-dimensional sections of the first waveform curved surface component and the second waveform curved surface component in the x direction or the y direction, the waveforms of the sections in the same direction altogether have n periods, the lengths of the periods are L1 and L2 respectively, L1 is equal to 2 and L2, and N is equal to 2n; the first wave-shaped curved surface component and the second wave-shaped curved surface component are nested and buckled through concave and convex curved surfaces to form a single-layer composite unit; and the plurality of single-layer composite units are periodically stacked in the z-axis positive direction of the space coordinate system o-xyz to form a three-dimensional honeycomb structure. The preparation method comprises the steps of hot press molding and assembling. The structure can bear loads from different directions, has high compression rigidity and excellent shearing performance, and is very suitable for multi-axis loads.

Description

Technical Field

[0001] This invention belongs to the field of mechanical metamaterials technology, specifically relating to a three-dimensional honeycomb structure based on nested waveform surfaces and its preparation method. Background Technology

[0002] Existing honeycomb structures are mainly used in aerospace, shipbuilding, construction, automotive, and mechanical engineering. Traditional honeycomb structures are a typical lightweight, high-strength porous material. Their configuration is primarily based on the periodic arrangement of hexagonal honeycombs found in nature, offering advantages such as lightweight, high strength, earthquake resistance, and high space utilization. To meet the specific needs of different working conditions, various honeycomb structures have been developed based on the traditional hexagonal honeycomb, including square honeycomb, triangular honeycomb, circular honeycomb, and hybrid honeycomb (such as a combination of quadrilateral and hexagonal structures), satisfying both mechanical performance and engineering requirements.

[0003] Significant progress has been made in the design, fabrication, mechanical characterization, and application of mechanical metamaterials. Most applications focus on their multifunctional properties, such as inherent isomorphism and energy absorption. The mechanical properties of metamaterials depend primarily on the specific configuration and arrangement of their internal structure, rather than the properties of the material itself. In other words, the macroscopic properties of metamaterials largely depend on the unique topological form of their internal cellular structure. Because the mechanical properties of metamaterials are closely related to their cellular topological configuration, optimizing the topological configuration of metamaterials can improve their mechanical properties.

[0004] Compared to traditional materials, metamaterials are artificially designed materials with extraordinary physical properties that natural materials do not possess, such as high porosity, low relative density, and high energy absorption and dissipation. The most distinctive feature of metamaterial design is the topology optimization design and spatially ordered distribution on the key physical dimensions of the material structure, which enables the material structure with special multi-scale (macro and micro) mechanical design to exhibit metamaterial properties that natural materials do not possess.

[0005] Based on traditional honeycomb structures, mechanical metamaterials are introduced into honeycomb structures through structural design, forming honeycomb metamaterial structures. Among these honeycomb metamaterials, those that achieve improved specific stiffness and specific strength or other special physical properties by nesting smaller-scale honeycomb structures within traditional honeycomb walls are called multi-level honeycomb metamaterials. The core idea is "layered optimization of structure," that is, repeating or changing honeycomb units at different scales to enhance their mechanical properties.

[0006] However, in current nested cellular structures, the nested unit geometry is simple, which can only achieve unidirectional stiffness enhancement (along the nesting direction), resulting in an imbalance of multi-directional load-bearing capacity and making it difficult to meet the requirements of complex multi-axis loads; stress concentration is significant at the nested parts, reducing structural reliability. Summary of the Invention

[0007] The purpose of this invention is to provide a three-dimensional honeycomb structure based on nested waveform surfaces and its preparation method, which helps to solve the problems of single load-bearing direction, low stiffness and significant anisotropy of traditional honeycomb structures in the engineering field.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a three-dimensional honeycomb structure based on nested waveform surfaces, comprising a first waveform surface component and a second waveform surface component. Both the first and second waveform surface components are periodic concave-convex surfaces extending along the xy plane, each period containing one peak and one trough. In the two-dimensional cross-section of the first waveform surface component in the x or y direction, the waveform in the same direction has a total of n periods, and the period length is L1. In the two-dimensional cross-section of the second waveform surface component in the x or y direction, the waveform in the same direction has a total of n periods, and the period length is L2, and L1=2L2, N=2n in the same direction. The first waveform surface component and the second waveform surface component are nested and interlocked to form a single-layer composite unit. The four vertices of the outer edges of the two components coincide. One wave peak of the first waveform surface component corresponds to two adjacent wave peaks of the second waveform surface component. The wave trough of the first waveform surface component contacts the corresponding wave peak of the second waveform surface component. Using the two adjacent sides of a single-layer composite unit as the x-axis and y-axis of the spatial coordinate system o-xyz, multiple single-layer composite units are periodically stacked along the positive z-axis of the spatial coordinate system o-xyz to form a three-dimensional honeycomb structure. In two adjacent single-layer composite units, the crest of the first waveform surface component of one single-layer composite unit is inserted into the crest of the second waveform surface component of the other single-layer composite unit, and the tops of the two crests do not contact each other.

[0009] Furthermore, the cross-sectional waveform of the first waveform surface component in the two-dimensional cross-section in the x-direction or y-direction has an inclination angle θ1, and the value of θ1 ranges from 30° to 60°.

[0010] Furthermore, the cross-sectional waveform of the second waveform surface component in the two-dimensional cross-section in the x or y direction has an inclination angle θ2, the value of θ2 is in the range of 30°~60°, and θ1≠θ2.

[0011] Furthermore, the first and second waveform surface components are made of aluminum alloy plates or steel plates.

[0012] Furthermore, the edges of the first and second waveform surface components extend outward by a certain distance.

[0013] This invention also proposes a method for preparing a three-dimensional honeycomb structure, wherein the three-dimensional honeycomb structure adopts the above-described three-dimensional honeycomb structure based on nested waveform surfaces, and includes the following steps: Step 1: Prepare the first mold and the second mold, which have cavities corresponding to the first and second waveform surface components, respectively; Step 2: Place the sheet material in the first mold and hot press it to form the first wave-shaped curved surface component; Step 3: Place the sheet material in the second mold and hot press it to form the second wave-shaped curved surface component; Step 4: Assemble the prepared first and second waveform surface components and bond them together with adhesive at the contact points to obtain a single-layer composite unit; Step 5: Stack multiple single-layer composite units at the same angle and bond them together with adhesive at the contact points to obtain the desired three-dimensional honeycomb structure.

[0014] Furthermore, the sheet material used is aluminum alloy sheet or steel sheet. For aluminum alloy sheet, the hot pressing temperature is 380°~450° and the pressure value is 50-150MPa; for steel sheet, such as low carbon steel, the hot pressing temperature is 700°-900° and the pressure value is 50-200MPa.

[0015] The beneficial effects of this invention are: This invention breaks through the limitations of traditional two-dimensional or simple three-dimensional honeycomb structures in design and manufacturing. It adopts a three-dimensional honeycomb structure based on nested wave surfaces to construct a honeycomb model with a concave topology. The concave-convex matching can withstand loads from different directions and has a certain buffering effect. It has a unique deformation mechanism, high compressive stiffness and excellent shear performance, and is very suitable for multiaxial loads. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural schematic diagram of the first waveform surface component of the present invention; Figure 2 This is a three-dimensional structural schematic diagram of the second waveform surface component of the present invention; Figure 3 This is a three-dimensional assembly diagram of the three-dimensional honeycomb structure of the present invention; Figure 4 This is a two-dimensional cross-sectional view of the first waveform surface component; Figure 5 This is a two-dimensional cross-sectional view of the second waveform surface component; The markings in the figure are: 1. First waveform surface component, 2. Second waveform surface component, 3. Single-layer composite unit, 4. Two-dimensional section. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the invention in any way.

[0018] Example 1 See attached document Figure 3 As shown, a three-dimensional honeycomb structure based on nested waveform surfaces includes multiple single-layer composite units 3, each of which includes a first waveform surface component 1 and a second waveform surface component 2.

[0019] like Figure 1 , 2 As shown, the first waveform surface component 1 and the second waveform surface component 2 are both periodic concave and convex surfaces extending along the xy plane, and each period contains one peak and one trough.

[0020] like Figure 4 As shown, in the two-dimensional cross-section 4 of the first waveform surface component 1 in the x-direction, the cross-sectional waveform is a sine wave with an inclination angle of θ1 and a period length of L1. There are a total of n periods in the same direction, so the total length l is n·L1. The first waveform surface component 1 also has the same waveform in the two-dimensional cross-section 4 in the y-direction as in the x-direction.

[0021] like Figure 5 As shown, in the two-dimensional cross-section 4 of the second waveform surface component 2 in the x-direction, the cross-sectional waveform is a sine wave with an inclination angle of θ2 and a period length of L2. There are a total of N periods in the same direction, so the total length l is N·L2. The second waveform surface component 2 also has the same waveform in the two-dimensional cross-section 4 in the y-direction as in the x-direction.

[0022] like Figure 4 , 5 As shown, the tilt angle θ1 is defined as follows: In the two-dimensional section 4 of the first waveform surface component 1, with the lowest point (valley) of a single complete waveform (containing one peak and one trough) as the origin O and the horizontal direction as the x-axis, a tangent line is drawn from the origin O to the rising segment of the waveform curve on the peak side. The maximum angle between this tangent line and the positive x-axis is the tilt angle θ1. The tilt angle θ2 in the two-dimensional section of the second waveform surface component is defined in the same way as the tilt angle θ1.

[0023] The period length refers to the projection length of a complete waveform (peak + trough) in the horizontal direction (x-axis or y-axis) in the two-dimensional cross section of the first waveform surface component 1 (or the second waveform surface component 2).

[0024] In this invention, L1=2 L2, N=2n, n·L1= N·L2, the values ​​of tilt angle θ1 and tilt angle θ2 are in the range of 30°~60°, and θ1≠θ2.

[0025] In this embodiment, the tilt angle θ1 of the first waveform surface component 1 is 60°, L1 is 60mm, and the number of periods n is 5. Therefore, the total horizontal length l of the two-dimensional cross-section 4 of the first waveform surface component 1 is 300mm, and the height of the first waveform surface component 1, i.e., the vertical distance from the crest to the trough, is approximately 26mm. In other embodiments, the tilt angle θ1 of the first waveform surface component 1 is 45°, L1 is 60mm, the number of periods n is 5, and the height is approximately 15mm.

[0026] The tilt angle θ2 of the second wave-shaped surface component 2 is 30°, L2 is 30mm, and the number of periods n is 10. Therefore, the total horizontal length l of the two-dimensional cross-section 4 of the second wave-shaped surface component 2 is 300mm, and the height of the second wave-shaped surface component 2, i.e., the vertical distance from the crest to the trough, is approximately 4mm. In other embodiments, the tilt angle θ2 of the second wave-shaped surface component 2 is 60°, L2 is 30mm, the number of periods n is 10, and the height is approximately 7.5mm.

[0027] Furthermore, the first waveform surface component 1 can be formed through the following process: establishing a spatial coordinate system o-xyz, with respective coordinates on the x-axis and y-axis. Figure 4 The waveforms shown (ignoring their thickness) intersect at the origin o at their endpoints. The waveform on the x-axis is moved along the y-axis to obtain... Figure 1 The first waveform surface component 1 is shown. It can be obtained in the same way. Figure 2 The second waveform surface component 2 is shown.

[0028] The single-layer composite unit 3 is formed by nesting and interlocking the first waveform surface component 1 and the second waveform surface component 2 with concave and convex surfaces. Since the total length of the two-dimensional cross-section 4 of the first waveform surface component 1 and the second waveform surface component 2 is the same in the horizontal direction, the four vertices of the outer edges of the two components completely overlap. After interlocking, one peak of the first waveform surface component 1 corresponds to two adjacent peaks of the second waveform surface component 2, and all peaks protrude in the same direction. The trough of the first waveform surface component 1 contacts the corresponding peak of the second waveform surface component 2.

[0029] In this invention, the first waveform surface component 1 and the second waveform surface component 2 are rectangular. Therefore, with the adjacent two sides of the single-layer composite unit 3 as the x-axis and y-axis of the spatial coordinate system o-xyz, multiple single-layer composite units 3 are periodically stacked along the positive z-axis of the spatial coordinate system o-xyz to form a three-dimensional honeycomb structure. In the three-dimensional honeycomb structure, the convex side of the first waveform surface component 1 of one single-layer composite unit 3 can be inserted into the concave side of the second waveform surface component 2 of the other single-layer composite unit 3, but the tops of the two peaks do not contact each other; instead, the curved surfaces near the peaks contact each other.

[0030] This invention constructs a novel omnidirectional, high-stiffness, three-dimensional multilayer auxiliary honeycomb structure by imitating an egg tray model, in order to solve the problems of low stiffness and significant anisotropy faced by traditional three-dimensional materials.

[0031] Example 2 A method for preparing the three-dimensional honeycomb structure described in Example 1 includes the following steps: Step 1: Prepare the first mold and the second mold. The first mold and the second mold have cavities corresponding to the first wave-shaped surface component 1 and the second wave-shaped surface component 2, respectively. Step 2: Place the sheet material in the first mold and hot press it to form the first wave-shaped curved surface component 1; Step 3: Place the sheet material in the second mold and hot press it to form the second wave-shaped curved surface component 2; Step 4: Assemble the prepared first waveform surface component 1 and second waveform surface component 2, and bond them together with adhesive at the contact points to obtain a single-layer composite unit 3; Step 5: Stack multiple single-layer composite units 3 at the same angle and bond them together with adhesive at the contact points to obtain the desired three-dimensional honeycomb structure.

[0032] In this method, the sheet material used is aluminum alloy sheet or steel sheet. For aluminum alloy sheet, the hot pressing temperature is 380°~450° and the pressure value is 50-150MPa; for steel sheet, such as low carbon steel, the hot pressing temperature is 700°-900° and the pressure value is 50-200MPa.

[0033] The edges of the first wave-shaped surface component 1 and the second wave-shaped surface component 2 extend outward by a certain distance to facilitate bonding, for example, they can extend outward by 3mm.

[0034] In this invention, the three-dimensional honeycomb structure is considered a thin-film structure without any platform. Considering that the bending stiffness of each layer is negligible compared to its tensile / compressive stiffness, each layer can be further simplified to a mechanism composed of infinitely parallelograms connected by hinges. The four nodes at the four corners of each layer can be considered as four hinge supports, and this mechanism has been proven to be a single-degree-of-freedom motion system. Given that the model has five independent design parameters: angles θ1 and θ2, total length L, and component thicknesses t1 and t2, to emphasize the significant influence of the bending angle on adjusting the macroscopic elasticity of the structure, this invention focuses on the influence of two main geometric parameters, θ1 and θ2. A series of representative angles are selected and combined, with a fixed total length L = 300 mm and thicknesses t1 = t2 = 1 mm. The complex 3D honeycomb is decomposed into two types of alternating stacked curved egg tray-shaped structures, and the elasticity of the three-dimensional honeycomb structure under different angle combinations is analyzed. The study shows that the macroscopic strain of the three-dimensional honeycomb structure along the three principal axes of this invention is only related to the angles of the model under the theoretical model.

[0035] In this embodiment, the prepared three-dimensional honeycomb structure was tested by a quasi-static compression test and modeled and simulated using the finite element software ABAQUS.

[0036] When using the quasi-static compression test, the upper and lower pressure plates are in contact with the upper and lower end faces of the three-dimensional honeycomb structure. The lower pressure plate is fixed, and a preset compression displacement is applied at the center position of the upper pressure plate, pressing down at 0.1 mm / s for 20 mm.

[0037] When using simulation calculations for verification, the friction coefficient between the pressure plate and the three-dimensional honeycomb structure in the quasi-static compression test was simulated, and the downward pressure was set to 20 mm.

[0038] Using the same method, the three-dimensional honeycomb structure was flipped 90° vertically and subjected to a quasi-static compression test, with compressive displacement applied to the left and right directions of the three-dimensional honeycomb structure for testing. Simultaneously, the finite element software ABAQUS was used for modeling and simulation verification.

[0039] Coupled experimental and simulation results, the findings demonstrate that the three-dimensional honeycomb structure of this invention possesses high compressive stiffness and excellent omnidirectional shear performance, making it highly suitable for multiaxial loading. It also exhibits strong anisotropic elastic adjustment capabilities and a controllable dominant deformation mechanism. Compared to traditional three-dimensional molding materials, the three-dimensional reinforced structure studied in this invention exhibits superior specific stiffness. This work helps overcome limitations in areas such as 3D oxygen-enriched materials, and is particularly crucial in applications requiring robust load-bearing capacity.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the specific implementation of the present invention with reference to the above embodiments. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the pending claims.

Claims

1. A three-dimensional honeycomb structure based on nested waveform surfaces, characterized in that: The system includes a first waveform surface component and a second waveform surface component. Both the first and second waveform surface components are periodic concave-convex surfaces extending along the xy plane, with each period containing one peak and one trough. In the two-dimensional cross-section of the first waveform surface component in the x or y direction, the waveform in the same direction has a total of n periods, and the period length is L1. In the two-dimensional cross-section of the second waveform surface component in the x or y direction, the waveform in the same direction has a total of n periods, and the period length is L2. In the same direction, L1 = 2L2, and N = 2n. The first waveform surface component and the second waveform surface component are nested and interlocked to form a single-layer composite unit. The four vertices of the outer edges of the two components coincide. One wave peak of the first waveform surface component corresponds to two adjacent wave peaks of the second waveform surface component. The wave trough of the first waveform surface component contacts the corresponding wave peak of the second waveform surface component. Using the two adjacent sides of a single-layer composite unit as the x-axis and y-axis of the spatial coordinate system o-xyz, multiple single-layer composite units are periodically stacked along the positive z-axis of the spatial coordinate system o-xyz to form a three-dimensional honeycomb structure. In two adjacent single-layer composite units, the crest of the first waveform surface component of one single-layer composite unit is inserted into the crest of the second waveform surface component of the other single-layer composite unit, and the tops of the two crests do not contact each other.

2. The three-dimensional honeycomb structure according to claim 1, characterized in that: The first waveform surface component has a tilt angle θ1 in the two-dimensional cross-section in the x or y direction, and the value of θ1 is in the range of 30° to 60°.

3. The three-dimensional honeycomb structure according to claim 2, characterized in that: The second waveform surface component has a tilt angle θ2 in the two-dimensional cross section in the x or y direction. The value of θ2 is in the range of 30° to 60°, and θ1 ≠ θ2.

4. The three-dimensional honeycomb structure according to claim 1, characterized in that: The first and second waveform surface components are made of aluminum alloy plates or steel plates.

5. The three-dimensional honeycomb structure according to claim 1, characterized in that: The edges of the first and second waveform surface components extend outward by a certain distance.

6. A method for fabricating a three-dimensional honeycomb structure, wherein the three-dimensional honeycomb structure adopts the three-dimensional honeycomb structure based on waveform surface nesting as described in any one of claims 1-5, characterized in that: Includes the following steps: Step 1: Prepare the first mold and the second mold, which have cavities corresponding to the first and second waveform surface components, respectively; Step 2: Place the sheet material in the first mold and hot press it to form the first wave-shaped curved surface component; Step 3: Place the sheet material in the second mold and hot press it to form the second wave-shaped curved surface component; Step 4: Assemble the prepared first and second waveform surface components and bond them together with adhesive at the contact points to obtain a single-layer composite unit; Step 5: Stack multiple single-layer composite units at the same angle and bond them together with adhesive at the contact points to obtain the desired three-dimensional honeycomb structure.

7. The method for preparing a three-dimensional honeycomb structure according to claim 6, characterized in that: The sheet material used is aluminum alloy sheet or steel sheet. For aluminum alloy sheet, the hot pressing temperature is 380°~450° and the pressure is 50-150MPa; for steel sheet, such as low carbon steel, the hot pressing temperature is 700°-900° and the pressure is 50-200MPa.

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