Strength cross-progressive buffer energy-absorbing structure

Abstract

This invention provides a strength-advanced buffer energy-absorbing structure, relating to the fields of impact protection and buffering technology. It employs a negative Poisson's ratio honeycomb structure with carbon fiber reinforcement units grafted between the layers, thereby constructing a cross-network of strength along the direction perpendicular to the impact force. The internal friction performance of the carbon fiber reinforcement units is optimized by adjusting the amount of carbon fiber incorporated. The spring-like stiffness of the carbon fiber reinforcement units is flexibly controlled by adjusting their wall thickness. The elastic deformation range of the structure is expanded by ensuring that the gaps between adjacent carbon fiber reinforcement units are smaller than the elastic deformation of the negative Poisson's ratio structure. Based on the deformation and failure characteristics of the negative Poisson's ratio honeycomb structure, carbon fiber reinforcement units with different parameters are configured in a top-to-bottom order to achieve a progressive distribution of strength along the impact force direction. This ensures load-bearing capacity while simultaneously matching and coordinating the increase in the structure's elastic deformation range and the improvement of energy absorption rate, resulting in a structure that combines high energy absorption, high load-bearing capacity, and high elasticity.

Description

Technical Field

[0001] This invention relates to the field of impact protection and cushioning technology, and in particular to a cross-strength progressive cushioning energy absorption structure. Background Technology

[0002] The cushioning molding pad is a key device that provides personalized support and protection for astronauts. Its ideal functional requirements are: closely conforming to the astronaut's body curves, having a certain load-bearing capacity, being able to efficiently absorb the huge impact energy when the return capsule lands, and responding quickly and recovering from low and medium speed impacts caused by parachute deployment, airflow disturbances, and retro-rockets.

[0003] Currently, most existing cushioning pads use highly elastic polymer foam materials or conventional honeycomb structures. However, these structures have an inherent trade-off in terms of mechanical properties: if high-density, high-strength materials or cell configurations are used, although the load-bearing capacity is improved, the structural stiffness is too high, the elastic deformation range is small, and the impact energy is mainly dissipated by material crushing, making it difficult to achieve multiple cushioning and rapid recovery; conversely, if low-density, highly elastic materials or cell configurations are used, although larger elastic deformation and good resilience can be obtained, the load-bearing capacity is insufficient, and under high-speed impact, it is prone to overall penetration or local collapse, with limited energy absorption efficiency.

[0004] More importantly, existing honeycomb structures are typically spatially uniform or have a single gradient, meaning that within the same structure, the material properties and geometric parameters of each layer or region are essentially the same. This uniform design results in a lack of phased control over the structure's mechanical response during impact: either local yielding occurs in the early stages of impact, or the remaining energy cannot be effectively dissipated in the later stages. Therefore, existing technologies struggle to simultaneously meet the synergistic requirements of "high energy absorption, high load-bearing capacity, and high elasticity." This problem severely limits the full effectiveness of cushioning pads in protecting astronauts from impact and is a significant reason why astronauts face a higher risk of fractures during reentry and landing.

[0005] Most innovative research on negative Poisson's ratio honeycomb structure configurations is based on changes in cell geometry parameters, selection of new functional materials, or foam filling. These methods improve the impact protection capability of the structure by changing the force-displacement relationship in the plateau region and the plateau reinforcement region. For low-velocity impacts, impact protection is achieved through irreversible plastic deformation. Summary of the Invention

[0006] This invention proposes a strength-crossing progressive buffer energy absorption structure, which aims to solve the technical problem that existing buffer structures, due to their single configuration, are difficult to coordinate in terms of high energy absorption, high load-bearing capacity and high elasticity, and cannot achieve phased and controllable dissipation of impact energy.

[0007] This invention provides a strength-crossing progressive buffer energy absorption structure, which includes multiple negative Poisson's ratio honeycomb structure sheets. The structure is characterized in that carbon fiber reinforced unit structure sheets composed of multiple carbon fiber reinforced units are embedded between the multiple negative Poisson's ratio honeycomb structure sheets. The energy-absorbing buffer structure consists of negative Poisson's ratio honeycomb structure sheets and carbon fiber reinforced unit structure sheets arranged alternately along the direction perpendicular to the impact force. The surface of each carbon fiber reinforced unit structural sheet is connected to the opposite surface of the negative Poisson's ratio honeycomb structural sheet; The carbon fiber reinforcing units are arranged in a cross pattern according to the strength parameters along the direction perpendicular to the impact force, and the carbon fiber reinforcing units are distributed progressively along the direction of the impact force in order of increasing strength parameters.

[0008] Furthermore, the Poisson's ratio honeycomb structure sheet is composed of multiple nodes and interconnections between the nodes.

[0009] Furthermore, the material of the negative Poisson's ratio honeycomb structure layer is thermoplastic polyurethane; the material of the carbon fiber reinforcement unit is carbon fiber reinforced polyurethane elastomer composite material.

[0010] Furthermore, the carbon fiber reinforcing unit includes a type I carbon fiber reinforcing unit, which is a spring-shaped rotating structure with a hollow interior; the two end faces of the type I carbon fiber reinforcing unit are respectively connected to the nodes on the surface of adjacent negative Poisson's ratio honeycomb structure sheets.

[0011] Furthermore, the carbon fiber reinforcement unit includes a type II carbon fiber reinforcement unit (4), which is an hourglass-shaped hollow tensile structure; the two end faces of the type II carbon fiber reinforcement unit are respectively connected to the surface of the adjacent negative Poisson's ratio honeycomb structure sheet, and the centroid of the type II carbon fiber reinforcement unit coincides with the centroid of the node on the surface of the negative Poisson's ratio honeycomb structure sheet.

[0012] Furthermore, the carbon fiber reinforcing unit includes a type III carbon fiber reinforcing unit, which is a four-arm fan-shaped structure. The two end faces of the type III carbon fiber reinforcing unit are respectively connected to the surface of the adjacent negative Poisson's ratio honeycomb structure sheet, and the centroid of the type III carbon fiber reinforcing unit coincides with the centroid of the node on the surface of the negative Poisson's ratio honeycomb structure sheet.

[0013] Furthermore, the gap between two adjacent carbon fiber reinforcing units is smaller than the elastic deformation of the negative Poisson's ratio honeycomb structure sheet.

[0014] Furthermore, the buffer energy-absorbing structure also includes sealing plates disposed at both ends of the negative Poisson's ratio honeycomb structure sheet along the impact direction.

[0015] Furthermore, the strength parameter is determined by three factors: the wall thickness of the carbon fiber reinforcement unit, the amount of carbon fiber incorporated, or the cross-sectional shape.

[0016] Compared with the prior art, the present invention has the following advantages: (1) The structure design with cross-strength along the vertical direction of the impact force and progressive strength along the direction of the impact force is adopted. The carbon fiber reinforced polyurethane elastomer and thermoplastic polyurethane negative Poisson's ratio honeycomb structure are organically combined. Compared with the traditional buffer structure, this cross-strength progressive structure can achieve the three functions of high energy absorption, high load-bearing capacity and high elasticity.

[0017] (2) The carbon fiber reinforced unit adopts carbon fiber reinforced polyurethane elastomer composite material, which greatly improves the internal friction energy absorption efficiency of the material. Under the same impact conditions, the energy absorption rate is better than that of traditional foam and conventional honeycomb structure.

[0018] (3) The strength is progressively distributed along the direction of impact force to gradually improve the structural bearing capacity. Under high-speed impact, it is not easy to cause overall crushing and failure, and the stability is stronger.

[0019] (4) The carbon fiber reinforced unit has three forms: Type I spring-shaped rotating body structure, Type II hourglass-shaped hollow tensile body structure, and Type III four-arm fan blade structure. It can be selected according to the impact level and the environment in which it is used, and has high flexibility.

[0020] (5) The carbon fiber reinforced unit adopts a spring-like section design, and its spring-like stiffness can be flexibly adjusted by adjusting the wall thickness. The gap between adjacent connected units is controlled to be less than the elastic deformation of the negative Poisson's ratio structure, thereby expanding the elastic deformation range of the structure.

[0021] (6) The Type I connecting unit is a spring-shaped rotating body structure. Its internal hollow part has the same shape as the outside and is a rotating body structure. When it is impacted, it will spread the impact force to all sides, which improves the buffering and energy absorption capacity.

[0022] (7) The Type II connecting unit is an hourglass-shaped hollow tensile body structure. The inside is hollow and the outside is an hourglass-shaped tensile body. When the structure is subjected to impact in its tensile direction, it has a stronger buffering and energy absorption capacity.

[0023] (8) The Type III connecting unit is a four-arm fan blade structure. When it is impacted, the impact force will be dispersed along the direction of the fan blades. The fan blades contact each other and can quickly buffer and absorb energy through the fan blades.

[0024] (9) The strength cross-progression structure of the present invention can achieve buffer energy absorption through large elastic deformation range and high internal friction during low-speed impact, delaying the plastic deformation of the structure while maintaining a certain load-bearing capacity, effectively reducing the damage to the structure caused by low-speed impact during parachute opening, airflow disturbance and retro-thrust ignition, and improving the protective effect of the buffer shaping pad on astronauts during landing. Attached Figure Description

[0025] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein: Figure 1 This is a layered diagram of a type I carbon fiber reinforcement unit with a strength-progressive cross structure. Figure 2 Front view (left) and left view (right) of negative Poisson's ratio layer diagram; Figure 3 Isometric view of a type I carbon fiber reinforced unit with a strength-advancing cross structure; Figure 4 Front view (left) and cross-sectional view (right) of Type I carbon fiber reinforced unit; Figure 5 Cell diagram of a type I carbon fiber reinforced unit with a strength-progressive cross structure; Figure 6 Isometric view of a type II carbon fiber reinforced unit with a strength-advancing cross structure; Figure 7 This is a front view of a Type II carbon fiber reinforced unit; Figure 8 This is a cell diagram of a type II carbon fiber reinforcement unit with a strength-progressive cross structure. Figure 9 Isometric view of a Type III carbon fiber reinforced unit with a strength-advancing cross structure; Figure 10 Front view of a Type III carbon fiber reinforced unit and three different surfaces; Figure 11 This is a cell diagram of a type III carbon fiber reinforced unit with a strength-advancing cross-strength structure.

[0026] In the figure: 1. Sealing plate; 2. Negative Poisson's ratio honeycomb structure layer; 3. Type I carbon fiber reinforcement unit; 4. Type II carbon fiber reinforcement unit; 5. Type III carbon fiber reinforcement unit; 6. Carbon fiber reinforcement unit structure layer. Detailed Implementation

[0027] The exemplary embodiments disclosed in this application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0028] This invention is based on the principles of momentum and energy conservation. Through the implementation of this invention, during experiments, reference is made to... Figure 1 In terms of connection, the structure uses thermoplastic polyurethane negative Poisson's ratio honeycomb structure layer 2 as the main deformation energy-absorbing unit. Multiple negative Poisson's ratio honeycomb structure layers 2 can be arranged sequentially along the vertical direction of impact. The carbon fiber reinforced unit structure layer 6 is set between the negative Poisson's ratio honeycomb structure layers 2 or in the local connection areas of the negative Poisson's ratio honeycomb structure layers 2, and is used to realize force transmission and coordinated deformation between adjacent honeycomb units or adjacent negative Poisson's ratio honeycomb structure layers 2. The carbon fiber reinforced unit structure layer 6 is composed of multiple carbon fiber reinforced units, and the carbon fiber reinforced units are not uniformly and singly arranged, but are spatially distributed according to the design principle of cross-strength parameters and progression along the impact force direction: in the vertical direction of impact force, connection areas with different strengths or different material parameters are arranged cross-stitched to avoid the impact load being concentrated in a single area; in the direction of impact force, the strength of each layer or each connection area changes progressively according to a predetermined gradient, so that the structure can deform in stages and absorb energy step by step during the impact process.

[0029] The effect of the carbon fiber reinforcement units crossing in the direction perpendicular to the impact force and advancing in the direction of the impact force is to increase the elastic range of the structure. This effect is generated in both the transverse and longitudinal directions, thereby improving the structural yield strength and structural energy absorption rate.

[0030] The blending ratio of carbon fiber reinforcement units can be freely adjusted according to requirements. For example, it can be adjusted so that the strength of the structure is either enhanced from top to bottom (along the direction of impact force) or degraded.

[0031] The carbon fiber reinforcement units in the carbon fiber reinforced unit structure layer 6 include three types: type I carbon fiber reinforcement unit 3, type II carbon fiber reinforcement unit 4, and type III carbon fiber reinforcement unit 5.

[0032] refer to Figures 1 to 11A strength-crossing progressive buffer energy-absorbing structure includes a sealing plate 1, a negative Poisson's ratio honeycomb structure layer 2, and type I carbon fiber reinforcement units 3. First, the spatial distribution relationship between the type I carbon fiber reinforcement units 3 and the thermoplastic polyurethane negative Poisson's ratio honeycomb structure layer 2 needs to be established, and this spatial distribution relationship is mapped to structural parameters of strength crossing along the vertical direction of the impact force and strength progression along the impact force direction. Second, based on the target protection requirements, the size of the negative Poisson's ratio honeycomb structure layer 2, cell configuration, position of the type I carbon fiber reinforcement units 3, material composition of the type I carbon fiber reinforcement units 3, carbon fiber doping amount of the type I carbon fiber reinforcement units 3, and strength gradient of each layer are determined. Third, a quadratic sequential programming algorithm is used to combine and optimize the above configuration parameters to obtain the optimal configuration scheme that meets the requirements of high elasticity, high load-bearing capacity, and high energy absorption. Finally, the optimized type I carbon fiber reinforcement units 3 and the negative Poisson's ratio honeycomb structure layer 2 are molded or assembled according to the determined spatial distribution relationship to form a strength-crossing progressive carbon fiber reinforced composite material structure.

[0033] In use, the energy-absorbing buffer structure is fixed or embedded in the location requiring protection, such as seat cushions, reentry capsule molding pads, or other parts subjected to impact loads. The upper surface of the structure faces the source of the impact load, and the lower surface contacts the protected object or supporting substrate, thus achieving energy absorption during an impact. Connecting units of different shapes, wall thicknesses, and carbon fiber incorporation amounts are selected based on the actual impact conditions, load-bearing requirements, and allowable deformation space. Thicker walls are less prone to permanent deformation under heavy loads, but under light loads, excessive thickness makes deformation difficult and the effect insignificant; the wall thickness is selected based on the required load. The carbon fiber incorporation amount is a general term; it refers to controlling the energy properties of the material by adjusting the amount of carbon fiber incorporated. Regarding cross-sectional shapes, Type I has moderate strength, Type II has slightly weaker strength, and Type III has the highest strength.

[0034] By adjusting the wall thickness of the type I carbon fiber reinforced unit 3, its spring-like stiffness can be changed; by adjusting the carbon fiber incorporation amount, the strength and internal friction energy dissipation performance of the connecting units can be optimized; by setting the gap between adjacent connecting units to be smaller than the elastic deformation of the thermoplastic polyurethane negative Poisson's ratio structure, the elastic deformation range of the overall structure can be expanded; by configuring connecting units with different parameters sequentially from top to bottom along the impact force transmission direction, the structural strength is distributed progressively along the impact force direction. The carbon fiber reinforced units near the impact end can preferentially undergo elastic deformation and absorb the initial impact energy, while the middle and lower carbon fiber reinforced units further bear, buffer, and dissipate the remaining impact energy, thereby avoiding premature local failure of the structure; when an external impact acts on the structure, the negative Poisson's ratio honeycomb structure layer 2 first undergoes synergistic deformation, and its contraction or expansion characteristics along the vertical direction of the impact force help improve the overall stability and compressive strength of the structure; at the same time, the carbon fiber reinforced units of the negative Poisson's ratio honeycomb structure layer 2 undergo bending, compression, torsion, or contact deformation, converting the impact energy into material internal friction energy, elastic deformation energy, and structural deformation energy dissipation.

[0035] For Type III carbon fiber reinforced unit 5, i.e., fan-blade type connecting unit, the impact force can be dispersed along the fan blade direction, and further rapid buffering and energy absorption can be achieved through the contact of adjacent fan blades. Under low-speed impact conditions, the cross-strength distribution along the perpendicular direction of the impact force can disperse the impact load, delay local plastic deformation of the structure, and at the same time maintain a high load-bearing capacity. The progressive strength distribution along the impact force direction can dissipate the impact energy step by step along the impact direction, expanding the effective elastic deformation range of the structure. Under high-speed impact conditions, this structure can promote the sequential participation of different regions in deformation and energy absorption, improve the ultimate energy absorption capacity of the structure, and reduce the relative velocity difference between adjacent loads. Single material or uniform strength structures are prone to local stress concentration, local collapse, or insufficient energy absorption under impact, making it difficult to simultaneously meet the requirements of high load-bearing capacity, high energy absorption, and large elastic deformation. By introducing a negative Poisson's ratio honeycomb layer 2, the overall coordinated deformation capacity of the structure under compressive impact can be improved; by introducing carbon fiber reinforcement units of carbon fiber reinforced polyurethane elastomer composite material, the nonlinear mechanical response and load-bearing capacity of polyurethane elastomer composite material can be improved; by arranging the strength in a cross pattern along the vertical direction of the impact force, the load can be redistributed in the plane, suppressing premature failure of weak areas; by arranging the strength in a progressive pattern along the impact force direction, the structure can deform and absorb energy step by step along the impact direction, thereby achieving controllable dissipation of impact energy.

[0036] Type II carbon fiber reinforced unit 4 is an hourglass-shaped hollow tensile structure. Its two end faces are connected to the surfaces of adjacent negative Poisson's ratio honeycomb structure layers 2, and the centroid of Type II carbon fiber reinforced unit 4 coincides with the centroid of the nodes on the surface of the negative Poisson's ratio honeycomb structure layer 2. Because this structure contracts in the middle and expands at both ends, under impact loads, the load is first transferred and dispersed at the connection points at both ends, and then progressive deformation and local buckling occur in the contracted middle section, thus achieving stepwise absorption of impact energy. Simultaneously, the coincident centroid setting helps reduce eccentric forces and torsional effects, improving connection stability and overall buffer consistency. Compared to Type I carbon fiber reinforced units, the deformation of the Type II structure is more progressive; compared to Type III carbon fiber reinforced units, its load-bearing strength and energy absorption strength are at an intermediate level, making it suitable for buffering and energy absorption scenarios under moderate impact conditions.

[0037] When a Type I is subjected to force, the force is evenly diffused along the edge of the connecting unit. When a Type II is subjected to force, the force is diffused along the vertical direction of the four inclined sides. When a Type III is subjected to force, the force is diffused as a whole through the contact of the fan blades. Type I is more widely applicable, Type II is suitable for scenarios with slightly smaller forces, and Type III is used in scenarios with large impacts.

[0038] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A strength-crossing progressive buffer energy absorption structure, the buffer energy absorption structure comprising multiple negative Poisson's ratio honeycomb structure layers (2), characterized in that, A carbon fiber reinforced unit structure layer (6) consisting of multiple carbon fiber reinforced units arranged together is embedded between multiple negative Poisson ratio honeycomb structure layers (2). The buffer energy absorption structure consists of negative Poisson's ratio honeycomb structure sheets (2) and carbon fiber reinforced unit structure sheets (6) arranged alternately along the direction perpendicular to the impact force. The surface formed by each carbon fiber reinforced unit structural sheet (6) is connected to the opposite surface of the negative Poisson's ratio honeycomb structural sheet (2); The carbon fiber reinforcing units are arranged in a cross pattern according to the strength parameters along the direction perpendicular to the impact force, and the carbon fiber reinforcing units are distributed progressively along the direction of the impact force in order of increasing strength parameters.

2. The strength-advanced buffer energy absorption structure according to claim 1, characterized in that, The Poisson's ratio honeycomb structure sheet (2) is composed of multiple nodes and the interconnection between the multiple nodes.

3. The strength-advanced buffer energy absorption structure according to claim 1, characterized in that, The material of the negative Poisson's ratio honeycomb structure layer (2) is thermoplastic polyurethane; the material of the carbon fiber reinforcement unit is carbon fiber reinforced polyurethane elastomer composite material.

4. The strength-advanced buffer energy absorption structure according to claim 1, characterized in that, The carbon fiber reinforcement unit includes a type I carbon fiber reinforcement unit (3), which is a spring-shaped rotating structure with a hollow interior. The two ends of the type I carbon fiber reinforced unit (3) are respectively connected to the nodes on the surface of the adjacent negative Poisson's ratio honeycomb structure layer (2).

5. The strength-advanced buffer energy absorption structure according to claim 1, characterized in that, The carbon fiber reinforcement unit includes a type II carbon fiber reinforcement unit (4), which is an hourglass-shaped hollow tensile body structure; The two ends of the Type II carbon fiber reinforced unit (4) are respectively connected to the surface of the adjacent negative Poisson's ratio honeycomb structure sheet (2), and the centroid of the Type II carbon fiber reinforced unit (4) coincides with the centroid of the node on the surface of the negative Poisson's ratio honeycomb structure sheet (2).

6. The strength-advanced buffer energy absorption structure according to claim 1, characterized in that, The carbon fiber reinforcement unit includes a type III carbon fiber reinforcement unit (5), which is a four-arm fan-shaped structure. The two ends of the type III carbon fiber reinforcement unit (5) are respectively connected to the surface of the adjacent negative Poisson's ratio honeycomb structure sheet (2), and the centroid of the type III carbon fiber reinforcement unit (5) coincides with the centroid of the node on the surface of the negative Poisson's ratio honeycomb structure sheet (2).

7. The strength-advanced buffer energy-absorbing structure according to claim 1, characterized in that, The gap between two adjacent carbon fiber reinforcement units is smaller than the elastic deformation of the negative Poisson's ratio honeycomb structure sheet (2).

8. The strength-advanced buffer energy absorption structure according to claim 1, characterized in that, The buffer energy absorption structure also includes sealing plates (1) respectively disposed at both ends of the negative Poisson's ratio honeycomb structure sheet (2) along the impact direction.

9. The strength-advanced buffer energy absorption structure according to claim 1, characterized in that, The strength parameter is determined by three factors: the wall thickness of the carbon fiber reinforcement unit, the amount of carbon fiber incorporated, or the cross-sectional shape.

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