A lightweight impact-resistant structure mimicking cattail fibers

Abstract

The present application relates to a kind of light impact-resistant structure of imitated cattail fiber, belong to energy-absorbing protective structure technical field, the present application is by several imitated cattail fiber impact-resistant unit plane array, spiral stacking, cutting forming composition;Impact-resistant unit includes flexible cavity structure and fiber thin wall structure, reliable connection is realized by positioning buckle and curl interlocking, flexible cavity structure imitates bionic cattail fiber diaphragm partition type hollow feature, fiber thin wall structure section imitates bionic cattail fiber heteromorphic section feature.The present application constructs "cavity compression-heteromorphic section toughening-rigid-flexible coupling" synergistic impact resistance mechanism, realizes gradient energy dissipation under dynamic impact, simultaneously, mechanical property precision customization can be realized by regulating structure parameter, with light weight, high buffering, high energy absorption and high structural stability advantage, and using modular design, maintenance and replacement are convenient, it is suitable for the light weight impact-resistant protection needs of aerospace, transportation, high-end protective equipment and other fields.

Description

Technical Field

[0001] This invention relates to a lightweight and impact-resistant structure based on imitation cattail fiber, which is suitable for applications such as aerospace, transportation, and high-end protective equipment where both lightweight and impact resistance are required. It belongs to the field of energy-absorbing protective structure technology. Background Technology

[0002] Composite materials, due to their excellent comprehensive properties, have been widely used in aerospace, transportation, and protective equipment. Among them, carbon fiber composites, with their advantages of low density, high specific strength, and high specific modulus, are gradually replacing traditional metal materials as the core material for key components such as aircraft skin and wings. The mechanical properties of carbon fiber composites can be controlled through layup design and structural optimization. For example, the helical layup method, which mimics the Brigan structure of a mantis shrimp, can deflect vertical crack propagation paths, thereby improving damage tolerance and impact resistance.

[0003] However, traditional carbon fiber composite materials have inherent technical defects: high overall stiffness and insufficient toughness, lack of flexible deformation capacity and multi-level energy dissipation mechanism, single impact energy dissipation form, easy to delamination, matrix cracking and fiber breakage under dynamic impact such as hail, sand and gravel, and birds, and strong concealment of impact damage, making it difficult to meet the high-efficiency protection requirements under complex dynamic impact.

[0004] Cattail fiber is a natural plant fiber with excellent properties. Its density is only half that of cotton, resulting in significant lightweight advantages. The tensile strength of the main fiber bundle can reach 106.9 MPa, about six times that of cotton fiber, and its cushioning and impact resistance are far superior to cotton. Its unique multi-chamber hollow structure is divided into multiple cavities by diaphragms, and the surface has bamboo-like protrusions. Compared with the single cylindrical hollow structure of kapok fiber, it has better structural stability and anti-collapse performance. At the same time, cattail fiber contains high levels of lignin and wax, which endows it with good structural stiffness, dimensional stability, hydrophobicity, and corrosion resistance. When subjected to impact, it can achieve multi-stage energy dissipation through cavity compression, diaphragm deformation, fiber slippage, and interfacial friction, simultaneously taking into account lightweight, cushioning, and impact resistance.

[0005] Currently, research on porous structures in fiber composites mainly focuses on honeycomb structures and metamaterial configurations. The application of biomimetic technology in composites is largely limited to layup optimization and wave-shaped structure design, resulting in relatively simple material systems and structural forms. Existing technologies have not yet achieved efficient integration of natural biomimetic fibers (cattail fibers) with traditional reinforcing materials (carbon fibers), nor have they developed composite structural forms suitable for this integration method. This has become a key technology restricting the development of lightweight, high-impact composite materials. Summary of the Invention

[0006] To address the challenges of low toughness, limited energy dissipation mechanisms, insufficient impact resistance, poor interlaminar toughness, and highly concealed impact damage in traditional carbon fiber composites, which are prone to failure under complex dynamic impacts, and the limited biomimetic applications of existing fiber composites that fail to organically integrate natural high-performance fibers such as cattail fibers with industrial carbon fibers, resulting in a lack of composite impact-resistant structures that combine lightweight, high cushioning, high energy absorption, and high structural stability, this invention provides a lightweight impact-resistant structure inspired by cattail fibers. Through a rigid-flexible coupled multi-level biomimetic configuration, it integrates the energy absorption advantages of flexible cavities with the load-bearing capacity of thin-walled fibers, solving the technical problems of low toughness, limited energy dissipation mechanisms, and insufficient impact resistance in traditional carbon fiber composites, and achieving a synergistic unity of lightweight, high cushioning, high energy absorption, and high structural stability.

[0007] A lightweight impact-resistant structure imitating cattail fluff fiber is formed by several cattail fluff fiber impact-resistant units arranged in a planar array, spirally stacked, and cut into shape; the cattail fluff fiber impact-resistant unit includes a flexible cavity structure and a fiber thin-wall structure, which are reliably connected by positioning buckles and curling interlocking. The flexible cavity structure is a cavity chamber. The main body of the cavity chamber is a ring-shaped semi-closed cavity composed of flexible thin walls, with an ear-shaped shape and a hollow feature with biomimetic cattail fiber membrane separation. The bottom annular area of ​​the cavity chamber is larger than the top annular area. The line connecting the geometric centers of the upper and lower annular rings is perpendicular to their respective planes. The thin-walled curves of the side walls are perpendicular to the upper and lower annular surfaces. A groove is opened on the inner side of the bottom of the cavity chamber. The top is closed by a rectangular flexible sheet with a large opening only at the bottom. Long strip through grooves are opened on both sides of the top sheet. Flow holes are provided at the front and rear of the upper part of the cavity chamber. The fiber thin-walled structure, from bottom to top, includes a π-type connector, an impact-resistant fiberboard layer, and a cup-shaped connector, with a cross-section that mimics the irregular cross-sectional features of cattail fluff fibers. The π-type connector is a micro-sized boss snap-fit ​​structure that matches the through groove at the top of the cavity for positioning and installation. The impact-resistant fiberboard layer is formed by spirally laying and hot-pressing multiple layers of fiber cloth. The cup-shaped connector is a raised interlocking structure that matches the size of the groove at the bottom of the cavity, and is engaged and locked by edge curling and flanging. The bottom of the cup-shaped connector matches the shape of the impact-resistant fiberboard layer.

[0008] The bottom annular area of ​​the cavity is more than 1.1 times the top annular area, and the height of the cavity does not exceed 1 / 2 of its width; the flow hole is circular, and its area does not exceed 1 / 8 of the cross-sectional area of ​​the cavity in the width direction; the cavity has rounded corners both inside and outside, and the surface is smooth, continuous, and free of stress concentration.

[0009] The cavity is made of thermoplastic polyurethane, and the fiber thin-wall structure is made of carbon fiber prepreg. The π-type connector and the cup-type connector are made of carbon fiber cloth pre-coated with epoxy resin, and the cross-section is biomimetic to the irregular cross-section characteristics of cattail fluff fiber.

[0010] The assembly method of a single imitation cattail fiber impact-resistant unit is as follows: epoxy resin is pre-coated on the upper plane of the cavity, the π-type connector of the fiber thin-wall structure is aligned with the through groove at the top of the cavity and assembled, and the unit is assembled after compaction and curing; two sets of units are inserted into the bottom groove of the cavity through cup-type connectors, and the curled and flanged edges are engaged and locked to achieve stable interlayer connection.

[0011] The lightweight and impact-resistant structure of the imitation cattail fiber is formed as follows: multiple hollow chambers are arrayed in planar array to form panel units, and multiple π-type connectors and cup-type connectors are arrayed to form corresponding panels. They are stacked and assembled in sequence to form a unit assembly, and cut into the target shape according to the usage scenario. The deflection angle is set between layers to achieve adjustable lateral stiffness.

[0012] The cup-shaped connector consists of a flanged cover and a flanged sealing ring. The flanged sealing ring has an annular hook-shaped cross section that precisely matches the cross section of the groove at the bottom of the cavity. After assembly, the flanged sealing ring is fully engaged with one side of the groove at the bottom of the cavity.

[0013] The π-type connector consists of two symmetrical slots and slot covers, with the lower curved semi-circular protrusion of the slot being slightly shorter than the upper straight section.

[0014] The impact-resistant fiberboard layer is laid up in one of the following ways: unidirectional layup, orthogonal layup, or biomimetic spiral layup.

[0015] The cavity is prepared by injection molding or high-precision photopolymerization 3D printing, and the fiber thin-walled structure is prepared by resin transfer molding or continuous carbon fiber 3D printing integral molding.

[0016] In the lightweight and impact-resistant structure of the imitation cattail fiber, the uppermost cup-shaped connector and the lowermost π-shaped connector are replaced with flat carbon fiber sheets. After overall hot pressing and curing, a structure with flat upper and lower surfaces is formed.

[0017] This invention, through a rigid-flexible coupled multi-level biomimetic configuration, integrates the energy absorption advantages of flexible cavities and the load-bearing capacity of thin-walled fibers, achieving a synergistic unity of lightweight, high buffering, high energy absorption, and high structural stability. Compared with existing technologies, it has the following outstanding and substantial technical effects: 1. Constructing a multi-level gradient energy dissipation mechanism significantly improves impact resistance and energy absorption efficiency: Inheriting the advantages of the multi-level structure of cattail fiber, a synergistic impact resistance mechanism of "cavity compression - irregular cross-section toughening - rigid-flexible coupling" is created to achieve gradient energy dissipation under dynamic impact. During impact, the rigid fiber thin-walled layer first disperses the load and initially absorbs energy; then, the multi-chamber hollow cavity of cattail fiber is elastically compressed, and secondary energy is dissipated through wall buckling and diaphragm deformation; finally, the TPU film is stretched, debonded, slipped, and squeezed to achieve tertiary energy dissipation. The multi-level process is progressive until the impactor is completely stationary, solving the problem of the single energy dissipation mechanism of traditional carbon fiber composite materials.

[0018] 2. Suppressing interlaminar crack propagation and improving structural stability and service life: Traditional thick fiberboard is broken down into multiple thin fiberboards, fundamentally preventing the large-scale initiation and propagation of interlaminar cracks; flexible TPU material is used to connect adjacent fiberboard layers, effectively hindering crack extension and shock wave propagation, and avoiding early failure caused by local stress concentration. At the same time, the irregular cross-section of the thin-walled fibers provides additional stiffness support for the carbon fiber layers, achieving a synergistic improvement in lightweight and impact resistance without significantly increasing weight.

[0019] 3. Precisely controllable mechanical properties to adapt to various application scenarios: By adjusting the diameter of the flow holes, the layup method of the impact-resistant fiberboard layers, and the interlayer angle, the structural stiffness and mechanical properties can be precisely customized. The diameter of the flow holes can adjust the damping of the cavity structure (small diameter provides high damping and strong support, while large diameter provides good vibration isolation), and the structural stiffness gradient distribution can be achieved through differentiated flow hole sizes; the layup method can be selected according to requirements, such as unidirectional (high bending resistance), orthogonal (high impact resistance), or biomimetic spiral (superior overall performance); the interlayer deflection angle can achieve directional reinforcement of the structure, adapting to load requirements in different directions, thus solving the problem of limited adaptability of existing impact-resistant structures.

[0020] 4. Modular design, convenient maintenance and low cost: The structure is assembled from independent impact-resistant unit arrays. After an impact, only the damaged unit or structural layer needs to be removed and replaced, without replacing the entire component, which significantly reduces maintenance costs and shortens the maintenance cycle. At the same time, the structural layer that has not broken can restore its initial shape through the deformation recovery capability of TPU, maintain the structural integrity, resist repeated impacts, improve the reusability of the structure, and ensure long-term stable service. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the lightweight and impact-resistant structure of the imitation cattail fiber of the present invention; Figure 2 This is a schematic diagram illustrating the assembly method of a lightweight, impact-resistant structure imitating cattail fiber to achieve the deflection effect between adjacent layer units according to the present invention. Figure 3 This is a half-sectional schematic diagram of the impact-resistant unit structure of the imitation cattail fiber in the lightweight impact-resistant structure of the imitation cattail fiber of the present invention. Figure 4 This is an exploded view of the impact-resistant unit structure of the imitation cattail fiber in the lightweight impact-resistant structure of the imitation cattail fiber of the present invention. Figure 5 This is a schematic diagram of the π-type connector in a lightweight, impact-resistant structure that mimics cattail fiber according to the present invention. Figure 6 This is a schematic diagram of the stacking of the impact-resistant fiberboard layer unidirectional carbon fiber resin composite material of the present invention; Figure 7 This is a half-sectional schematic diagram of the structure of the cup-shaped connector of the present invention.

[0023] In the diagram: 1-Cup connector; 101-Flanged cover; 102-Flanged sealing ring; 2-Impact-resistant fiberboard layer; 3-π-type connector; 301-Slot; 302-Slot cover; 4-Cavity. Detailed Implementation

[0024] 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.

[0025] like Figure 1 As shown, the lightweight impact-resistant structure of the imitation cattail fiber of the present invention is composed of several imitation cattail fiber impact-resistant units arranged in a planar array, stacked between layers and hot-pressed, and the whole is arranged in a modular manner, which can be cut and shaped according to the size and shape requirements of the application scenario.

[0026] like Figure 2 As shown, in order to achieve directional control of interlayer mechanical properties and optimization of impact resistance, multiple sets of cavity panels and fiber thin-walled structure panels can be prefabricated. During interlayer assembly, the fiber thin-walled structure deflects by a preset angle layer by layer. The deflection angle of adjacent unit panels is precisely controlled by the relative angle between the π-type connector and the cup-type connector. By adjusting the deflection angle, the anisotropic stiffness of the structure can be customized to adapt to load requirements in different directions.

[0027] like Figure 3 and Figure 4 As shown, a single imitation cattail fiber impact-resistant unit consists of four parts: a cup-shaped connector 1, an impact-resistant fiberboard layer 2, a π-shaped connector 3, and a cavity 4. These components are mechanically interlocked and bonded with resin to achieve an integrated connection. The cup-shaped connector 1 is composed of a flanged cover 101 and a flanged sealing ring 102, and its structure is as follows: Figure 7 As shown. The flanged sealing ring 102 has an annular hook-shaped cross-section, and its size is precisely matched with the cross-section of the bottom groove of the cavity 4. After assembly, the flanged sealing ring 102 can fully engage with one side of the bottom groove of the cavity 4. By pressing, the bottom plane of the cavity 4 is tightly attached to the surface of the flanged sealing ring 102, which not only achieves interlayer sealing, but also forms a reliable mechanical locking connection, avoiding interlayer separation under impact. The impact-resistant fiberboard layer 2 is made of carbon fiber prepreg through spiral layup and hot pressing, and the layup method is as follows. Figure 6 As shown, in this embodiment, a helical layup with an angle of 15° is preferred, which can effectively deflect the vertical crack propagation path and improve the damage tolerance and impact resistance of the laminate. Depending on the application scenario, unidirectional layup (0°), orthogonal layup (±45°), or biomimetic hybrid layup can also be used to achieve directional optimization of bending, shear, and impact resistance. The π-type connector 3 consists of two symmetrical slots 301 and slot caps 302, and its structure is as follows: Figure 5 As shown, the lower curved semi-circular protrusion of the slot 301 is slightly shorter than the upper straight section, providing sufficient installation space for the through slot of the upper thin plate of the cavity 4, ensuring that the π-type connector 3 can be accurately inserted during assembly and avoiding interference.

[0028] As a preferred embodiment, a single imitation cattail fiber impact-resistant unit is 5mm long, 1.2mm wide, and 0.9mm high.

[0029] In a preferred embodiment, the structural parameters of the cavity 4 are set as follows: height 0.55mm, side wall thickness 0.03mm~0.05mm, ensuring structural support rigidity while maintaining good elastic deformation capacity; an arched flow hole is provided at the upper part of the cavity 4, the upper straight edge of the flow hole is flush with the upper surface of the cavity, the arch height is 0.1mm, and the lower arc radius is 0.05mm, which can improve airflow smoothness while ensuring structural damping characteristics; a through groove is opened at the top of the cavity 4, the through groove is 4.8mm long and 0.3mm wide, for precise matching with the π-type connector 3; all corner positions of the cavity 4 are provided with rounded chamfers of 0.02mm~0.04mm to eliminate stress concentration, improve structural impact resistance, and facilitate smooth demolding of the molding mold.

[0030] In a preferred embodiment, the cavity 4 is prepared by injection molding. The injection mold is made of aluminum alloy material and is integrally formed by 3D printing. The surface of the mold cavity is finely polished to a smooth state to ensure that the cavity after molding has uniform thin walls, smooth surface, high dimensional accuracy, and no flash, shrinkage marks, or bubble defects.

[0031] The cavity 4 is prepared using a high-precision photopolymerization 3D printing process, which can further improve the forming accuracy, surface quality and geometric consistency of the thin-walled structure, and meet the requirements for the preparation of high-precision biomimetic structures.

[0032] In a preferred embodiment, the cup-shaped connector 1, the impact-resistant fiberboard layer 2, and the π-type connector 3 in the fiber thin-walled structure are all manufactured using resin transfer molding (RTM) technology. This allows for the integrated and synchronous molding of the three components, ensuring the interfacial bonding strength and structural integrity. The resin transfer molding mold adopts a segmented design, adapting to the complex configurations of the cup-shaped connector 1 and the π-type connector 3 respectively, ensuring the complete molding of complex structural parts. Specifically, the π-type connector 3 is formed by laying three layers of unidirectional carbon fiber prepreg, with the fiber layup direction perpendicular to the length direction of the π-type connector 3, significantly improving the tensile strength, shear strength, and pull-out resistance of the connection area. The impact-resistant fiberboard layer 2 is continuously laid in a spiral layup manner, with the cup-shaped connector 1 laid on the top layer. A single layer of woven carbon fiber cloth is used, first laying the flanged sealing ring 102 area, then laying the flanged cap 101 area. After resin injection and hot-press curing, excess material is removed, and the surface is finely polished to obtain a smooth, dimensionally accurate fiber thin-walled structure.

[0033] As a preferred embodiment, the dimensions of each part of the fiber thin-walled structure are set as follows: the cup-shaped connector 1 has a single-layer plate thickness of 0.2 mm and a flange height of 0.2 mm; the impact-resistant fiberboard layer 2 is made of seven layers of carbon fiber prepreg spirally laid at a 15° angle, and the thickness after hot pressing and curing is 0.6 mm to 0.8 mm; the π-type connector 3 has a plate thickness of 0.3 mm and a connection protrusion height of 0.07 mm to ensure reliable engagement and sealing connection with the groove of the cavity 4.

[0034] The fiber thin-walled structure is integrally formed by continuous carbon fiber 3D printing, which can eliminate the lay-up and mold steps, and improve the structure forming efficiency, dimensional consistency and interface bonding performance.

[0035] After the cavity 4 is mass-produced in the form of a multi-unit integrated panel, epoxy resin adhesive is evenly sprayed onto the top thin sheet surface, and then precisely aligned and assembled with the fiber thin-walled π-type connector 3. During the assembly process, a special thin sheet positioning tool is used for auxiliary positioning, so that the edge of the through groove on the top of the cavity 4 is stably and accurately inserted into the protruding part of the π-type connector 3, ensuring that the assembly is in place, without deviation or warping. After the adhesive has initially cured, the subsequent interlayer stacking assembly and cutting process is carried out.

[0036] In preparing the overall surface and bottom layers of the imitation cattail fiber lightweight impact-resistant structure, the uppermost cup-shaped connector 1 and the lowermost π-shaped connector 3 are replaced with planar carbon fiber sheets. After overall hot-pressing composite and curing, the desired result can be obtained. Figure 1 The above and below surfaces are flat and smooth, forming a standard impact-resistant filling structure.

[0037] The impact energy absorption process of the structure: When the structure of this invention is subjected to external impact loads, its impact energy absorption process is divided into multi-stage progressive energy dissipation, and it has the characteristics of post-impact recovery and convenient maintenance: 1. Primary energy absorption: The top rigid carbon fiber plane evenly distributes the concentrated impact load to each impact-resistant unit below, and the initial energy dissipation is achieved in local areas through fiber micro-fracture, matrix cracking and pore formation.

[0038] 2. Secondary energy absorption: The cavity 4 adjacent to the impact surface encloses the fiber fragments and the impacting object, restricting fragment splashing and impact object slippage, and generating continuous elastic deformation under impact pressure until the TPU film is stretched, torn and fails, completing the secondary energy absorption; at the same time, the arrayed cavity 4 compresses and deforms synchronously, constrained by the cross-sectional size of the flow hole and the gas release rate, forming a controllable damping effect inside, efficiently absorbing and dissipating energy through cavity deformation, wall buckling and gas damping.

[0039] 3. Multi-stage energy continuation: If the remaining kinetic energy of the impactor is not completely dissipated, the fiber thin-walled rigid structure and the flexible cavity structure alternately bear the load and fail step by step. Energy is continuously absorbed through mechanisms such as interlayer debonding, snap-fit ​​slippage, fiber breakage, and cavity compression until the impactor comes to a complete stop.

[0040] 4. Post-impact recovery and repair: After the impact process ends, the structural layers that have not fractured or broken will recover their initial shape through the deformation recovery capability of TPU, maintaining structural integrity to resist repeated impacts; during equipment maintenance, only the damaged structural layers or local units need to be removed and replaced, without the need to replace the entire component, which significantly reduces maintenance costs and shortens the maintenance cycle.

[0041] This invention inherits the advantages of the multi-level structure of cattail fluff fibers and constructs a synergistic impact resistance mechanism of "cavity compression - irregular cross-section toughening - rigid-flexible coupling," which can achieve gradient energy dissipation under dynamic impact. Upon impact, the rigid fiber thin-walled layer first undergoes localized breakage and deformation, dispersing the impact load to a larger bearing surface and initially absorbing the impact energy. Subsequently, the multi-chamber hollow cavity imitating cattail fluff undergoes elastic compression, further dissipating energy through cavity wall buckling and diaphragm deformation. Simultaneously, a thermoplastic polyurethane (TPU) film bonded to the impacted fiber layer encapsulates the broken fibers and the impactor. During stretching, the film gradually detaches and slips from the π-type connector, continuously compressing the local cavity until the polyurethane ruptures, achieving the third stage of energy dissipation. These multi-level energy dissipation stages proceed progressively and continuously until the impactor comes to a complete stop, significantly improving the structure's impact resistance and energy absorption efficiency.

[0042] This invention breaks down traditional thick fiberboard into multiple thin fiberboard layers, fundamentally suppressing the large-scale initiation and propagation of interlayer cracks. Adjacent fiberboard layers are connected by a flexible material, effectively hindering crack extension and shock wave propagation, making it difficult for crack nuclei to form in fiberboards far from the impact surface, thus avoiding early failure caused by localized stress concentration. Simultaneously, the irregular cross-sectional structure of the thin-walled fibers provides additional stiffness support to the carbon fiber layers, achieving a synergistic improvement in lightweighting and impact resistance without significantly increasing the overall structural weight. Furthermore, thermoplastic polyurethane, as a superelastic material, can self-recover through elastic deformation after impact, providing a reliable guarantee for the long-term stable service of the structure. This invention achieves precise control over structural stiffness and mechanical properties by adjusting the diameter of the flow holes, the layup method of the impact-resistant fiberboard layers, and the interlayer angles. The cattail-like impact-resistant unit has a long strip configuration and exhibits significant anisotropy (stiffness in the width direction is lower than in the length direction). By adjusting the interlayer deflection angle, directional reinforcement of the structure can be achieved to adapt to load requirements in different directions. The impact-resistant fiberboard layers can be laid in unidirectional directions (0°, high bending strength), orthogonal layup (±45°, high impact resistance), or biomimetic spiral layup (excellent comprehensive performance), etc., to customize performance for different application scenarios and expand the applicability of the structure. Adjusting the diameter of the flow holes can change the structural damping of the cavity, similar to the principle of high-speed rail air springs: the smaller the diameter of the flow holes, the higher the structural damping and the stronger the cavity support effect, but the vibration isolation effect is weakened; the larger the diameter of the flow holes, the lower the structural damping and the stronger the vibration isolation effect, but the impact resistance is reduced. Furthermore, by using different flow hole sizes in different layers of the cavity, a gradient distribution of structural stiffness can be achieved, improving environmental adaptability.

[0043] In summary, this invention provides a lightweight impact-resistant structure based on cattail fiber. Through a multi-level biomimetic hollow configuration, a rigid-flexible coupling energy dissipation mechanism, and a modular and replaceable design, it improves the structure's impact resistance, energy absorption efficiency, and reusability while ensuring lightweight design. It is suitable for lightweight impact protection needs in aerospace, transportation, and high-end protective equipment fields.

[0044] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A lightweight, impact-resistant structure imitating cattail fluff fiber, characterized in that: It is composed of several imitation cattail fiber impact-resistant units arranged in a planar array, spirally stacked, and cut into shape; the imitation cattail fiber impact-resistant unit includes a flexible cavity structure and a fiber thin-wall structure, which are reliably connected by positioning buckles and curling interlocking. The flexible cavity structure is a cavity chamber. The main body of the cavity chamber is a ring-shaped semi-closed cavity composed of flexible thin walls, with an ear-shaped shape and a hollow feature with biomimetic cattail fiber membrane separation. The bottom annular area of ​​the cavity chamber is larger than the top annular area. The line connecting the geometric centers of the upper and lower annular rings is perpendicular to their respective planes. The thin-walled curves of the side walls are perpendicular to the upper and lower annular surfaces. A groove is opened on the inner side of the bottom of the cavity chamber. The top is closed by a rectangular flexible sheet with a large opening only at the bottom. Long strip through grooves are opened on both sides of the top sheet. Flow holes are provided at the front and rear of the upper part of the cavity chamber. The fiber thin-walled structure comprises, from bottom to top, a π-type connector, an impact-resistant fiberboard layer, and a cup-type connector. The π-type connector is a micro-sized boss snap-fit ​​structure that matches the through groove at the top of the cavity for positioning and installation. The impact-resistant fiberboard layer is formed by spirally laying and hot-pressing multiple layers of fiber cloth. The cup-type connector is a raised interlocking structure that matches the size of the groove at the bottom of the cavity. It achieves engagement and locking by curling and flanging the edges. The bottom of the cup-type connector matches the shape of the impact-resistant fiberboard layer.

2. The lightweight and impact-resistant structure of imitation cattail fiber according to claim 1, characterized in that: The bottom annular area of ​​the cavity is more than 1.1 times the top annular area, and the height of the cavity does not exceed 1 / 2 of its width; the flow hole is circular, and its area does not exceed 1 / 8 of the cross-sectional area of ​​the cavity in the width direction; the cavity has rounded corners both inside and outside, and the surface is smooth, continuous, and free of stress concentration.

3. The lightweight, impact-resistant structure of imitation cattail fiber according to claim 1 or 2, characterized in that: The cavity is made of thermoplastic polyurethane, and the fiber thin-wall structure is made of carbon fiber prepreg; the π-type connector and the cup-type connector are made of carbon fiber cloth pre-coated with epoxy resin.

4. The lightweight and impact-resistant structure of imitation cattail fiber according to claim 1, characterized in that: The assembly method of a single imitation cattail fiber impact-resistant unit is as follows: epoxy resin is pre-coated on the upper plane of the cavity, the π-type connector of the fiber thin-wall structure is aligned with the through groove at the top of the cavity and assembled, and the unit is assembled after compaction and curing; two sets of units are inserted into the bottom groove of the cavity through cup-type connectors, and the curled and flanged edges are engaged and locked to achieve stable interlayer connection.

5. The lightweight, impact-resistant structure of imitation cattail fiber according to claim 1 or 4, characterized in that: The lightweight and impact-resistant structure of the imitation cattail fiber is formed as follows: multiple hollow chambers are arrayed in planar array to form panel units, and multiple π-type connectors and cup-type connectors are arrayed to form corresponding panels. They are stacked and assembled in sequence to form a unit assembly, and cut into the target shape according to the usage scenario. The deflection angle is set between layers to achieve adjustable lateral stiffness.

6. The lightweight and impact-resistant structure of imitation cattail fiber according to claim 1, characterized in that: The cup-shaped connector consists of a flanged cover and a flanged sealing ring. The flanged sealing ring has an annular hook-shaped cross section that precisely matches the cross section of the groove at the bottom of the cavity. After assembly, the flanged sealing ring is fully engaged with one side of the groove at the bottom of the cavity.

7. The lightweight and impact-resistant structure of imitation cattail fiber according to claim 1, characterized in that: The π-type connector consists of two symmetrical slots and slot covers, with the lower curved semi-circular protrusion of the slot being shorter than the upper straight section.

8. The lightweight and impact-resistant structure of imitation cattail fiber according to claim 1, characterized in that: The impact-resistant fiberboard layer is laid up in a unidirectional layup, orthogonal layup, or biomimetic spiral layup.

9. The lightweight and impact-resistant structure of imitation cattail fiber according to claim 1, characterized in that: The cavity is prepared by injection molding or high-precision photopolymerization 3D printing, and the fiber thin-walled structure is prepared by resin transfer molding or continuous carbon fiber 3D printing integral molding.

10. The lightweight and impact-resistant structure of imitation cattail fiber according to claim 1, characterized in that: In the lightweight and impact-resistant structure of the imitation cattail fiber, the uppermost cup-shaped connector and the lowermost π-shaped connector are replaced with flat carbon fiber sheets. After overall hot pressing and curing, a structure with flat upper and lower surfaces is formed.

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