Interface contact nonlinear regulation metamaterial and design method thereof
By using nonlinearly controlled metamaterials for interfacial contact design, combined with elastic frames and interfacial contact structures, the buffer design problem of spacecraft landers in complex environments was solved, achieving higher energy dissipation and stability, and optimizing the buffer performance of spacecraft landers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING INST OF TECH
- Filing Date
- 2024-04-28
- Publication Date
- 2026-05-29
AI Technical Summary
Existing spacecraft lander cushioning designs cannot achieve adjustable performance in complex landing environments, and honeycomb structures and particle damping technologies suffer from performance instability and lack of customization.
A metamaterial with nonlinear control of interface contact is designed. By combining an elastic framework and an interface contact structure, and using a classical honeycomb structure theoretical model, an equivalent modulus is established. The equivalent modulus of the overall cell structure is obtained by linear superposition. The interface contact form is optimized to improve the dissipation performance.
It achieves higher energy dissipation performance and stable structural design in complex landing environments, and has lightweight and stable dissipation performance that is superior to simple honeycomb structures and damping particle technology.
Smart Images
Figure CN118447972B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of impact protection technology for aerospace landing structures, and in particular to a metamaterial with nonlinear controllable interface contact and its design method. Background Technology
[0002] The immense impact force during spacecraft landing is one of the main threats to spacecraft landing, significantly impacting the spacecraft's lifespan. With the deepening exploration of exoplanets, the need for landing of new spacecraft is increasing significantly, making impact protection crucial. Such impacts can easily damage the external structure of the lander and cause fatal damage to equipment and personnel inside. Therefore, implementing impact protection measures for the external structure of the lander is essential to effectively prevent or mitigate damage from landing impacts.
[0003] For soft landing impacts, the speed is generally several meters per second or more than ten meters per second, and the maximum impact response acceleration during the landing process is generally more than ten g or tens of g. The existing main buffering technologies are based on the following principles: (1) material deformation technology; (2) airbag form; (3) electromagnetic damping buffer mechanism; (4) particle damping, etc. From the successful experience of various countries in landers, it can be seen that the leg-type buffer landing mechanism is a relatively common buffer design. The main transmission path of the shock wave to the equipment inside the spacecraft during a soft landing is: ground → landing legs → lander body → internal base → equipment / person. From the transmission path of the landing shock wave, it can be seen that improving the impact resistance of the lander mainly starts from the landing legs.
[0004] Research on lander cushioning is similar to the protection strategies for car collisions, but due to the differences in constraints between the space and ground environments, the specific implementation methods often differ significantly. Furthermore, the reliability requirements for landing legs are far higher than those for car protection. While the landing process is brief compared to the entire lifecycle of a spacecraft, it determines its success or failure. Crush material cushioning design has been widely implemented in industry since the last century. With the increasing attention given to porous materials, sandwich structures utilizing plastic deformation have been extensively studied. Related porous materials, such as foam materials, honeycomb materials, and lattice structures, possess excellent impact resistance, reducing the energy acting on the protected object. They dissipate shock wave energy through plastic deformation, ultimately greatly reducing the impact energy transmitted to the protected object. However, this approach suffers from the problem of passively selecting structural performance based on the material. Particle damping and other technologies exhibit characteristics such as performance instability.
[0005] Currently, my country's design of porous materials for landers remains at the level of ordinary honeycomb material properties, making it impossible to customize performance designs. There is a lack of novel energy-absorbing design concepts for achieving adjustable performance in complex landing environments. Summary of the Invention
[0006] The purpose of this invention is to provide an interface contact nonlinear control metamaterial and its design method, which solves the defects of existing honeycomb structures and particle damping buffer technology.
[0007] To achieve the above objectives, this invention provides an interfacial contact nonlinear control metamaterial and its design method, comprising the following steps:
[0008] Step S1: Based on actual needs, the equivalent modulus properties of the metamaterial with nonlinear modulation of interfacial contact are initially determined;
[0009] Step S2: Using the elastic frame as the main support structure of the nonlinearly modulated metamaterial at the interface, the equivalent modulus of the elastic frame is initially established through the classical honeycomb structure theoretical model.
[0010] Step S3: Based on the interface contact structure, preliminarily determine the equivalent modulus of the interface contact structure;
[0011] Step S4: Obtain the equivalent modulus of the overall cell structure through linear superposition;
[0012] Preferably, the nonlinear modulation of the interface contact metamaterial's impact resistance process in step S1 includes the material's compressive deformation, characterized by the compressive deformation of the elastic frame and the slip deformation of the interface contact structure. For an interface contact structure with a circular cross-section, the relationship between the force load and the applied displacement is as follows:
[0013]
[0014] The rotation angle θ of the beam section in the above formula is:
[0015]
[0016] The longitudinal displacement of the beam is:
[0017] x = 2R(Cos[α0] - Cos[α])
[0018] Among them, F x EI represents the force along the axial direction of the structure, μ represents the product of the material's elastic modulus and moment of inertia, R, H, α0 and L0 represent the radius of the circular convex body and other related geometric parameters.
[0019] This leads to a rough equivalent modulus:
[0020]
[0021] Preferably, the formula for establishing the equivalent modulus of the elastic frame in step S2 is as follows:
[0022]
[0023] Where E represents the material modulus, and the other parameters are geometric parameters.
[0024] Preferably, the interface contact structure in step S3 includes a sawtooth interface, a circular interface, an elliptical interface, and an obtuse-angled sawtooth interface.
[0025] Preferably, the equivalent modulus of the obtained elastic frame is linearly superimposed with the equivalent modulus of the interface contact structure to obtain the equivalent modulus of the overall cell structure:
[0026]
[0027] in, K represents the equivalent modulus of the elastic frame. C It represents the equivalent modulus of the interface contact structure.
[0028] Therefore, the interfacial contact nonlinear control metamaterial and its design method using the above-mentioned structure have the following beneficial effects:
[0029] (1) The interface contact cellular unit design provided by the present invention has higher dissipation performance than a simple cellular structure.
[0030] (2) The structural design of the present invention is more stable than that of damping particle technology, and has multiple advantages such as lightweight and stable dissipation performance.
[0031] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0032] Figure 1 This is a schematic diagram of the interface form of the interface contact structure of the present invention;
[0033] Figure 2 This is a schematic diagram of the elastic frame structure of the present invention;
[0034] Figure 3 This is a schematic diagram of the interface contact structure of the present invention;
[0035] Figure 4 This is a schematic diagram showing the changing trend of the equivalent modulus curve of the present invention;
[0036] Figure 5This is a schematic diagram of nonlinear control obtained by selecting different geometric structure-related parameters according to the present invention;
[0037] Attached image labels: 1. Sawtooth interface; 2. Circular interface; 3. Elliptical interface; 4. Obtuse-angled sawtooth interface. Detailed Implementation
[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0039] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0040] Example
[0041] Please see Figure 1-5 This invention provides an interfacial contact nonlinear control metamaterial and its design method, comprising the following steps:
[0042] Step S1: Based on actual needs, the equivalent modulus properties of the metamaterial with nonlinear modulation of interfacial contact are initially determined.
[0043] The nonlinear control process of the interface contact in step S1, which modulates the impact resistance of the metamaterial, includes the compressive deformation of the material. This is characterized by the compressive deformation of the elastic frame and the slip deformation of the interface contact structure. The outer frame primarily provides support for the circular protrusions and provides elastic recovery; therefore, the influence of the outer frame is ignored, and only the contact between the two circular protrusions is discussed to analyze the structural losses. From a mechanical perspective, this can be considered a fixed-support boundary condition; therefore, the calculation model for cantilever beams can be simplified to a typical beam deformation problem under moving loads. For the interface contact structure with a circular cross-section, the relationship between the force load and the applied displacement is as follows:
[0044]
[0045] The rotation angle θ of the beam section in the above formula is:
[0046]
[0047] The longitudinal displacement of the beam is:
[0048] x = 2R(Cos[α0] - Cos[α])
[0049] Among them, F x Represents the force along the axial direction of the structure; EI represents the product of the material's elastic modulus and moment of inertia; μ represents the Coulomb coefficient of friction; R, H, α0, and L0 represent the radius of the circular convex body and other related geometric parameters, and their represented dimensions are as follows: Figure 3 As shown, the geometric parameters of the elements for typical interface contact structures are listed. These parameters are selected to simplify the design. Figure 3 Only two identical snap-fit structures are used, arranged in parallel. The circular protrusions are standard circles. The contact point formed by the contact between the two snap-fit protrusions forms a certain angle with the longitudinal direction of the beam. This angle is denoted by α, where α0 represents the initial contact angle. Let R = 3mm, E = 1403MPa. L0 = 15mm, With μ = 0.2, the force-displacement relationship curve of the contact interface structure with specific values can be obtained.
[0050] This leads to a rough equivalent modulus:
[0051]
[0052] Step S2: Using the elastic frame as the main support structure of the nonlinearly modulated metamaterial at the interface, the equivalent modulus of the elastic frame is initially established through the classical honeycomb structure theoretical model.
[0053] Based on specific spatial dimensions, force-displacement curves, and other constraints, the equivalent modulus required for a preliminary elastic frame is established. The formula is as follows:
[0054]
[0055] Where E represents the material modulus, and the other parameters are geometric parameters, such as... Figure 2 As shown, the frame is designed in a hexagonal honeycomb shape, with no strict requirements on geometric dimensions, matching the geometric dimensions of the interface contact structure. In this embodiment, a circular interface is selected as the typical structure, where b = 10mm, a1 = 2mm, b 10 =60mm, b1=22mm, b8=35mm.
[0056] Step S3: Based on the interface contact structure, preliminarily determine the equivalent modulus of the interface contact structure.
[0057] The interface contact structure in step S3 is as follows Figure 1 As shown, the interfaces include sawtooth interface 1, circular interface 2, elliptical interface 3, and obtuse-angled sawtooth interface 4. The form of the interface contact is designed according to the required function; that is, when the structure slides relative to each other, the deformation caused by mutual constraint due to the interface contact can greatly dissipate energy through dry friction between the interfaces. The geometric parameters of the structure are initially determined based on the required energy loss value, and the preliminary equivalent modulus is obtained.
[0058] Step S4: Based on actual needs, obtain the equivalent modulus of the overall cell structure through linear superposition.
[0059] The equivalent modulus of the obtained elastic frame is linearly superimposed with the equivalent modulus of the interface contact structure to obtain the equivalent modulus of the overall cell structure:
[0060]
[0061] in, K represents the equivalent modulus of the elastic frame. C It represents the equivalent modulus of the interface contact structure.
[0062] By comparing the result with the desired modulus and fine-tuning the geometric parameters of the structure, the force-displacement curves of the elastic frame and the contact structure are superimposed to obtain... Figure 5 S-shaped curve in the middle.
[0063] Figure 4 This is a schematic diagram illustrating the changing trend of the equivalent modulus curve according to the present invention. The force-displacement curve under compressive load on the outer frame of the honeycomb structure is approximately linear, and can be considered as the mechanical behavior of a linear spring. The force-displacement curve under compressive load on the contact interface structure is approximately sinusoidal, exhibiting two different stiffness segments: positive stiffness and negative stiffness. Negative stiffness refers to the property that the force decreases as the loaded displacement increases; in some segments, the force value is also negative.
[0064] Figure 5 This is a schematic diagram of nonlinear control obtained by taking different geometric parameters according to the design method of this invention. By selecting different geometric parameters of the elastic frame, different equivalent moduli can be obtained. The adjustment of the geometric parameters and friction coefficient of the interface also affects the equivalent modulus of the contact interface structure. By assembling the elastic frame and the contact interface structure, the mechanical properties are linearly superimposed, thereby obtaining the equivalent modulus of the overall structure.
[0065] Therefore, the present invention provides an interface contact nonlinear control metamaterial and its design method using the above-mentioned structure. The interface contact honeycomb unit design provided has higher dissipation performance than a simple honeycomb structure. The structural design is more stable than the damping particle technology and has multiple advantages such as lightweight and stable dissipation performance.
[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A metamaterial with nonlinear controllable interfacial contact and its design method, characterized in that, Includes the following steps: Step S1: Based on actual needs, the equivalent modulus properties of the metamaterial with nonlinear modulation of interfacial contact are initially determined; Step S2: Using the elastic frame as the main support structure of the nonlinearly modulated metamaterial at the interface, the equivalent modulus of the elastic frame is initially established through the classical honeycomb structure theoretical model. Step S3: Based on the interface contact structure, preliminarily determine the equivalent modulus of the interface contact structure; Step S4: Obtain the equivalent modulus of the overall cell structure through linear superposition; The impact resistance process of the nonlinear modulation of the interface contact metamaterial in step S1 includes the compressive deformation of the material, characterized by the compressive deformation of the elastic frame and the slip deformation of the interface contact structure. For the interface contact structure with a circular cross-section, the relationship between the force load and the applied displacement is as follows: In the formula, Indicates the rotation angle of the beam cross section; The rotation angle of the beam section in the above formula for: The longitudinal displacement of the beam is: in, This represents the force along the axial direction of the structure. Represents the product of the material's elastic modulus and moment of inertia. Represents the Coulomb friction coefficient. , , and Represents the radius and other related geometric parameters of a circular convex body; This leads to a rough equivalent modulus: The formula for establishing the equivalent modulus of the elastic frame in step S2 is as follows: in, This represents the material modulus; the other parameters are geometric parameters.
2. The interface contact nonlinear control metamaterial and its design method according to claim 1, characterized in that: The interface contact structure in step S3 includes a sawtooth interface, a circular interface, an elliptical interface, and an obtuse-angled sawtooth interface.
3. The interface contact nonlinear control metamaterial and its design method according to claim 2, characterized in that: The equivalent modulus of the obtained elastic frame is linearly superimposed with the equivalent modulus of the interface contact structure to obtain the equivalent modulus of the overall cell structure: in, The equivalent modulus of the elastic frame. It represents the equivalent modulus of the interface contact structure.