Flexible energy absorption structure based on magnetic body element group movement interaction

Abstract

The invention relates to a flexible energy absorption structure based on magnetic body element group movement interaction, which comprises a magnetic particle body element structure and an external flexible wrapping film, the magnetic particle body element structure comprises a plurality of magnetic particle body elements, and the external flexible wrapping film is filled with the magnetic particle body element structure. The outer flexible wrapping film is sealed in a hot melting mode. Compared with the prior art, the composite material has the advantages of light weight, high impact resistance, large design and performance regulation space, high environment adaptability, good self-repairing capability and the like, and is widely applicable to application scenes such as impact resistance structures and vibration reduction protection structures of aircrafts.

Description

Technical Field

[0001] The present invention relates to the field of energy absorption devices, and in particular to a flexible energy absorption structure based on the interactive motion of a group of magnetic elements. Background Art

[0002] The fields of aerospace, drone systems, etc. all have common requirements for energy-absorbing structures that can resist impact, absorb and dissipate kinetic energy, and adapt to complex terrain environments, such as spacecraft recovery and landing, and drone anti-collision. Effectively absorbing impact energy, improving absorption efficiency, and having a low weight are the goals pursued by the design of such energy-absorbing structures.

[0003] However, the current traditional energy absorption structure design scheme mainly focuses on the adjustment of the structure, with a relatively single function, unable to self-repair, and difficult to take into account multiple functions such as lightweight, flexibility, energy dissipation, and absorption of external impact energy, and it is difficult to adapt to complex environmental changes. For example, patent application CN 115899131 A discloses a bistable flexible energy absorption protection structure and a preparation method, including two upper and lower hard horizontal layers, a flexible intermediate layer is arranged between the hard horizontal layers, the flexible intermediate layer includes a trapezoidal self-locking structure, and a flexible elastic rod is connected between the trapezoidal self-locking structures that are spaced relatively apart; the production steps are: using a 3D printer to print the upper and lower hard horizontal layers using resin materials; using acrylic plates to prepare an intermediate layer negative mold consistent with the flexible intermediate layer composed of the flexible elastic rod and the trapezoidal self-locking structure, pouring the silicone rubber mixture into the negative mold for curing and forming; finally, bonding the hard horizontal layer and the cured flexible intermediate layer; the method has a simple structure, is reliable, and is easy to prepare, but can only achieve a good low-speed impact protection function. Under rapid impact, the traditional elastic structure is prone to rebound, causing secondary impact and damage to equipment and devices. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a flexible energy-absorbing structure based on the interactive motion of a group of magnetic elements, so as to effectively realize the conversion of impact energy, prevent damage caused by secondary rebound, and protect the safety of equipment and devices under impact loads.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A flexible energy-absorbing structure based on the interactive motion of a group of magnetic elements comprises a magnetic particle element structure and an external flexible wrapping film, wherein the magnetic particle element structure comprises a plurality of magnetic particle elements, the magnetic particle element structure is filled in the external flexible wrapping film, and the external flexible wrapping film is sealed by hot melting.

[0007] Furthermore, the magnetic particle element is a hollow structure.

[0008] Furthermore, the magnetic particle element comprises an upper and lower part, and the upper and lower parts have the same shape but opposite magnetization directions.

[0009] Furthermore, the upper and lower parts of the magnetic particle element are stably bonded by magnetic force, and a snap-fit ​​design is used to prevent relative rotation.

[0010] Furthermore, the plurality of magnetic particle elements attract each other and are stacked, constrained, gridded, and arranged in a topological manner by virtue of the mutual attraction generated by their own magnetic materials.

[0011] Furthermore, the mutual attraction between any two of the magnetic particle elements is as follows:

[0012]

[0013] In the formula, the subscripts i and j represent two particles, μ0 is the spatial magnetic permeability, and r ij is the relative position vector between magnetic particles i and j, pointing to i, m ir and m jr is the component of the magnetic moment along the relative position vector.

[0014] Furthermore, the plurality of magnetic particle elements are in a densely stacked state, and the contact force exerted on a single magnetic particle element by the surrounding magnetic particle elements is as follows:

[0015] P=2Rwp0

[0016] Where P is the contact force, R is the radius of the magnetic particle, w is the number of magnetic particles, and p0 is the surface stress on the magnetic particles.

[0017] Furthermore, when subjected to an external impact load, the external flexible wrapping membrane constrains the overall deformation of the structure to be within a designed range.

[0018] Furthermore, under an external impact load, the magnetic particle element converts impact energy into energy of separation of the magnetic particle element and energy of contact friction and sliding between a plurality of the magnetic particle elements.

[0019] Furthermore, when the magnetic particle element structure is rubbed, the relationship between the friction force between the plurality of magnetic particle elements and the stress they bear is as follows:

[0020]

[0021] Among them, f is the friction force, α is the function related to the friction sliding surface, σ a is the impact stress, σ R is the normal stress, and p0 is the surface stress on the magnetic particles.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention utilizes the magnetic constraint effect between magnetic body elements and the blocking effect induced by the overall boundary constraint to absorb and dissipate the energy of the external load, generate surface constraint force, and effectively improve the kinetic energy absorption performance of the structure.

[0024] 2. The present invention utilizes the reshapeable magnetic field between magnetic elements to construct mutual dynamic constraints, realizes the flow plasticity of the structure and the adaptability to various dynamic loads, avoids the damage caused by the secondary impact caused by rebound, and achieves the purpose of protecting the onboard equipment.

[0025] 3. The present invention only uses common magnetic materials and flexible outer films. The magnetic particles can be directly manufactured by 3D printing. They are composed of two parts with the same structure and opposite magnetization directions. The two parts are stably bonded due to magnetic force, which is convenient for mass production and application.

[0026] 4. The present invention is based on the characteristics of magnetic potential interaction and exhibits flexible characteristics as a whole. After impact, the main change occurs in the shape, and the shape can be restored to achieve the purpose of reusing the energy-absorbing structure and saving resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention;

[0028] Figure 2 It is a single body perspective view of the magnetic unit energy absorption structure.

[0029] Figure numerals: 1. Magnetic particle volume element structure; 2. External flexible wrapping film. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0031] This embodiment provides a flexible energy absorption structure based on the interaction of magnetic body group motion, such as Figure 1 As shown, it includes a magnetic particle element structure 1 and an external flexible wrapping film 2. The magnetic particle element structure 1 includes a plurality of magnetic particle elements. The magnetic particle element structure 1 is filled in the external flexible wrapping film 2, and the external flexible wrapping film 2 is sealed by hot melting. The external flexible wrapping film 2 imposes flexible constraints on the magnetic particle elements, further enhancing the energy dissipation between the elements, and preventing some elements from escaping under high-speed impact, thereby achieving self-adaptation of the structural morphology.

[0032] like Figure 2As shown in the figure, the magnetic particle element is composed of two parts with the same structure and opposite magnetization directions. It is a hollow structure. The two parts are stably bonded due to magnetic force. At the same time, the buckle design is used to prevent their relative rotation and is not easy to separate under external impact. The magnetic particle element can be directly manufactured by 3D printing. If it is separated due to impact, it is necessary to overcome the close-range magnetic attraction to further absorb the dissipated energy.

[0033] Multiple magnetic particle elements rely on the mutual attraction generated by their own magnetic materials to attract each other, stack and constrain each other, and are arranged in a grid topology.

[0034] The mutual attraction between any two magnetic particle elements is as follows:

[0035]

[0036] In the formula, the subscripts i and j represent two particles, μ0 is the spatial magnetic permeability, and r ij is the relative position vector between magnetic particles i and j, pointing to i, m ir and m jr is the component of the magnetic moment along the relative position vector.

[0037] It can be seen that the attraction of magnetic materials will decay with the distance to a high power. The hollow structure greatly reduces the mass of magnetic particles while retaining most of the magnetic force. The average density of the finished product is 2.12g / mm 3 , which is close to the density of carbon fiber resin commonly used in aircraft.

[0038] Multiple magnetic particle elements are in a densely stacked state, and the contact force on a single magnetic particle element from the surrounding magnetic particle elements is as follows:

[0039] P=2Rwp0

[0040] Where P is the contact force, R is the radius of the magnetic particle, w is the number of magnetic particles, and p0 is the surface stress on the magnetic particles.

[0041] When the magnetic particle element is subjected to an external impact load, the impact energy is converted into the energy of separation of the magnetic particle element and the energy of contact friction and sliding between the magnetic particle elements. The internal magnetic particle element structure 1 will undergo motion modes such as friction, extrusion, collision and separation, and the energy of the external load is absorbed and dissipated during these motions. First, friction will convert the impact energy into frictional heat energy caused by the relative displacement of the particle surface. At the same time, relative extrusion will occur between the magnetic particles, and the generation of this relative displacement between the particles will bring about a change in magnetic potential, thereby converting part of the impact energy into magnetic potential energy dissipation. Further, when a large displacement occurs between the particles, it will cause the movement of the magnetic particles, converting part of the impact energy into kinetic energy, causing separation between the magnetic particles. At the same time, in order to overcome the mutual attraction of magnetic forces at close range, separation requires a large amount of energy. In addition, if the upper and lower parts of the magnetic particle unit are separated, energy will be further absorbed.

[0042] When friction occurs in the magnetic particle element structure 1, the relationship between the friction force between the magnetic particle elements and the stress they bear is as follows:

[0043]

[0044] Among them, α is a function related to the friction sliding surface, σ a is the impact stress, σ R is the normal stress, and p0 is the surface stress on the magnetic particles.

[0045] The constraint of the flexible wrapping film 2 will limit the overall deformation within the design range, and at the same time generate surface constraint force, combining the magnetic constraint between volume elements and the blocking effect induced by the overall boundary constraint. Such blocking effect will further hinder the relative movement inside the magnetic particle unit, thereby further enhancing the energy absorption effect.

[0046] The flexible energy-absorbing structure based on the interactive motion of a group of magnetic elements exhibits flow plasticity on a macroscopic level when subjected to impact loads. The elements adjust their relative positions and use the reshapeable magnetic field to construct dynamic constraints on each other, thereby achieving the flexible flow plasticity of the structural system, which is convenient for matching with various dynamic loads, achieving adaptability to dynamic loads and service environments, and can be reused. At the same time, this flow plasticity also facilitates timely switching of forms when subjected to impact to adapt to complex and changing environmental conditions. In addition, the performance of plastic flow can suppress the rebound effect of the system when it is impacted, thereby avoiding damage to the system caused by secondary impacts caused by elastic rebound, and achieving the purpose of protecting the onboard equipment.

[0047] Density is an important parameter in the design of impact-resistant structures. Impact-resistant design schemes of different densities directly determine whether related equipment can be carried. The magnetic particle element manufactured in this embodiment has a hollow design and reduces the density to approximately the same as that of carbon fiber without sacrificing its own magnetic attraction to a large extent, which is convenient for carrying when used in aerospace and other fields.

[0048] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A flexible energy-absorbing structure based on the interaction of magnetic body group motion, characterized in that: It comprises a magnetic particle element structure (1) and an external flexible wrapping film (2), wherein the magnetic particle element structure (1) comprises a plurality of magnetic particle elements, the magnetic particle element structure (1) is filled in the external flexible wrapping film (2), and the external flexible wrapping film (2) is sealed by hot melting.

2. The flexible energy-absorbing structure based on the interaction of magnetic body group motion according to claim 1 is characterized in that: The magnetic particle element is a hollow structure.

3. The flexible energy-absorbing structure based on the interaction of magnetic body group motion according to claim 1 is characterized in that: The magnetic particle element comprises an upper and a lower part, which have the same shape but opposite magnetization directions.

4. The flexible energy-absorbing structure based on the interaction of magnetic body group motion according to claim 3 is characterized in that: The upper and lower parts of the magnetic particle element are stably bonded by magnetic force, and a snap-fit ​​design is used to prevent relative rotation.

5. The flexible energy-absorbing structure based on the interaction of magnetic body group motion according to claim 1 is characterized in that: The plurality of magnetic particle elements are attracted to each other and stacked and constrained by the mutual attraction generated by their own magnetic materials, and are arranged in a grid topology.

6. The flexible energy-absorbing structure based on the interaction of magnetic body group motion according to claim 5 is characterized in that: The mutual attraction between any two of the magnetic particle elements is as follows: In the formula, the subscripts i and j represent two particles, μ0 is the spatial magnetic permeability, and r ij is the relative position vector between magnetic particles i and j, pointing to i, m ir and m jr is the component of the magnetic moment along the relative position vector.

7. The flexible energy-absorbing structure based on the interaction of magnetic body group motion according to claim 1 is characterized in that: The plurality of magnetic particle elements are in a densely stacked state, and the contact force exerted on a single magnetic particle element by the surrounding magnetic particle elements is as follows: P=2Rwp0 Where P is the contact force, R is the radius of the magnetic particle, w is the number of magnetic particles, and p0 is the surface stress on the magnetic particles.

8. The flexible energy-absorbing structure based on the interaction of magnetic body group motion according to claim 1 is characterized in that: When subjected to external impact loads, the external flexible wrapping membrane (2) constrains the deformation of the entire structure to be within a designed range.

9. The flexible energy-absorbing structure based on the interaction of magnetic body group motion according to claim 1, characterized in that: Under an external impact load, the magnetic particle elements convert impact energy into energy for separation of the magnetic particle elements and energy for contact, friction and sliding between a plurality of the magnetic particle elements.

10. The flexible energy-absorbing structure based on the interaction of magnetic body group motion according to claim 1, characterized in that: When the magnetic particle element structure (1) is rubbed, the relationship between the friction force between the plurality of magnetic particle elements and the stress they bear is as follows: Among them, f is the friction force, α is the function related to the friction sliding surface, σ a is the impact stress, σ R is the normal stress, and p0 is the surface stress on the magnetic particles.

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