Automobile energy absorption box and preparation method thereof

Abstract

The application discloses an automobile energy absorption box and a preparation method thereof, and relates to the technical field of automobile collision safety. The automobile energy absorption box comprises a front-end structure of a core body and a rear-end structure of the core body. The front-end structure of the core body is formed by an array of front-end structure cells of the core body, and the rear-end structure of the core body is formed by an array of rear-end structure cells of the core body. The front-end structure cells of the core body and the rear-end structure cells of the core body are both surrounded by an outer structure and an inner structure. The outer structure is a negative Poisson's ratio structure, and the inner structure is a positive Poisson's ratio structure. The automobile energy absorption box utilizes the torsion, compression and expansion deformation characteristics of the positive and negative Poisson's ratio cooperative structures to resist impact energy, fully absorbs kinetic energy caused by impact, and is integrally formed by SLM, thereby avoiding defects caused by traditional energy absorption box manufacturing and assembly, and improving the reliability and durability of the energy absorption box.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile crash safety, in particular to an automobile energy absorption box and a preparation method thereof. BACKGROUND

[0002] With the rapid development of the automobile industry, the vehicle population continues to grow, and collision accidents occur frequently. The safety performance of the automobile has become the core concern of consumers and industry supervision. As the first line of defense for collision energy absorption, the performance of the energy absorption box directly determines the rationality of the energy transmission path, the control effect of the peak impact force and the protection degree of the key structure such as the vehicle body longitudinal beam during the collision process. At the same time, it needs to take into account the demand for automobile lightweight, so it puts forward strict requirements for the comprehensive performance of the energy absorption box, i.e. lightweight, high energy absorption efficiency and structural stability.

[0003] However, the energy absorption box in the prior art generally has the following defects:

[0004] 1. The traditional energy absorption box generally adopts a simple unit structure, such as a hexagonal honeycomb, a square or a circular structure. When impacted, such a structure only produces a single expansion deformation, the deformation mode is single, the impact resistance is insufficient, and the energy absorption box has poor energy absorption effect, which can only absorb a small amount of collision energy, and the remaining energy will extend to the vehicle body, causing damage to the vehicle, and more seriously, causing harm to the passengers.

[0005] 2. In the traditional process, the energy absorption box has manufacturing and assembly defects, which cause stress concentration at the connection part during the collision, easily causing the core body to fall off or the shell to crack. SUMMARY

[0006] In order to solve the problems of insufficient impact resistance of the energy absorption box, deformation of the core structure of the energy absorption box, single energy absorption mode and assembly defects in the traditional process, the present application aims to provide an automobile energy absorption box and a preparation method thereof. According to the bionic negative Poisson's ratio feature and the hierarchical structure feature of the mantis shrimp's hard forefoot, a positive and negative Poisson's ratio cooperative structure is constructed, and then an embedded energy absorption core is generated. The advantages of SLM technology, such as the torsion, compression and expansion of the positive and negative Poisson's ratio cooperative structure and the advantages of additive manufacturing, such as reducing manufacturing defects, improve the crashworthiness of the energy absorption box and obtain good energy absorption performance.

[0007] The technical scheme is as follows:

[0008] The present application provides an automobile energy absorption box, comprising: two fixed plates and an energy absorption box shell, the two ends of the energy absorption box shell are fixedly connected with the two fixed plates, further comprising two bionic chiral energy absorption cores, the bionic chiral energy absorption cores are filled into the inside of the energy absorption box shell, and the two bionic chiral energy absorption cores are respectively a core front end structure and a core rear end structure.

[0009] The core front end structure is formed by an array of core front end structure cells, and the core rear end structure is formed by an array of core rear end structure cells;

[0010] The core front end structure cell and the core rear end structure cell are both surrounded by an outer structure and an inner structure, the outer structure is a negative Poisson's ratio structure, and the inner structure is a positive Poisson's ratio structure.

[0011] Further, the outer structure of the core front end structure cell is connected by six outer chiral structures, the six outer chiral structures are connected in the shape of a square, the center of the inner structure of the core front end structure cell is a square block, and the square block and the outer chiral structure are fixedly connected through a cylindrical rod.

[0012] Further, the center of the outer chiral structure is a circular ring, four rods are connected to the outer side of the circular ring, the rods are tangent to the circular ring, the angle between adjacent rods is the same, and the end of the rod in each outer chiral structure is connected to the end of the rod of the other two adjacent outer chiral structures.

[0013] The six faces of the square block are respectively opposite to the six circular rings of the outer chiral structures, each circular ring and the face of the square block opposite thereto are fixedly connected through four cylindrical rods, and the cylindrical rods are connected to the center of the edge of the square block.

[0014] Further, the inside of each face of the square block is connected with a cross structure, the cross structure is composed of two circular rods, and the end point of the cross structure is connected to the center of each edge.

[0015] Further, the outer structure of the core rear end structure cell is a negative Poisson's ratio honeycomb structure, the inner structure is a positive Poisson's ratio honeycomb structure, the negative Poisson's ratio honeycomb structure and the positive Poisson's ratio honeycomb structure are connected through a chiral connecting structure, and the chiral connecting structure is a negative Poisson's ratio structure.

[0016] Further, the negative Poisson's ratio honeycomb structure comprises two symmetrical and parallel side faces, the same side of the two side faces is connected through two connected inclined faces, and the two inclined faces are inclined inwardly.

[0017] The outer side of the positive Poisson's ratio honeycomb structure is a cylindrical body, and the center of the cylindrical body is a regular hexagonal cavity.

[0018] The chiral connecting structure is composed of four plates, one end of the four plates is tangent to the outer side of the cylindrical body, the angle between adjacent plates is the same, and the other end of the four plates is connected to the end of the two side faces of the negative Poisson's ratio honeycomb structure.

[0019] Further, the intersection of adjacent core rear end structure cells inside the core rear end structure forms a positive Poisson's ratio honeycomb structure.

[0020] Further, the fixed plate, the energy absorption box shell, the front end structure of the core and the rear end structure of the core are all made of aluminum alloy and plated with an anodic oxidation film.

[0021] The application also provides a preparation method of the automobile energy absorption box.

[0022] Step one, two models of biomimetic chiral energy absorption cores are established according to the helical chirality characteristics, and the two biomimetic chiral energy absorption cores include a front end structure of the core and a rear end structure of the core;

[0023] Step two, the two models of biomimetic chiral energy absorption cores established in step one are imported into three-dimensional printing software, and the two biomimetic chiral energy absorption cores are formed by using selective laser melting technology;

[0024] Step three, the two biomimetic chiral energy absorption cores in step two are filled into the energy absorption box shell;

[0025] Step four, the fixed plate and the energy absorption box shell are welded to complete the preparation of the automobile energy absorption box.

[0026] Further, the two biomimetic chiral energy absorption cores in step two are annealed after being formed.

[0027] The application has the following advantages:

[0028] The core of the automobile energy absorption box is surrounded by an external negative Poisson's ratio structure and an internal positive Poisson's ratio structure. Compared with the traditional honeycomb core energy absorption box, when the automobile energy absorption box is subjected to impact, the core structure of the automobile energy absorption box deforms cooperatively in the positive and negative Poisson's ratio structures, so that the energy absorption box changes from single expansion deformation to torsion-compression-expansion cooperative deformation to resist impact energy, and converts the impact energy into internal energy in the core, thereby fully absorbing the kinetic energy brought by the impact.

[0029] The core of the energy absorption box is designed with a front and rear double-core structure, which has the advantages of multiple deformation modes, multiple force transmission paths and multiple energy absorption, thereby greatly improving the stability of energy dissipation of the energy absorption box.

[0030] The preparation method of the automobile energy absorption box adopts SLM integrated molding, avoids the defects caused by the traditional energy absorption box manufacturing and assembly, improves the reliability and durability of the energy absorption box, and ensures the self-supporting in the 3D printing process. In addition, according to different vehicle models and different working conditions, the size and angle of the positive and negative Poisson's ratio structures and other parameters can be adjusted to cope with different impact conditions, which not only has low design threshold, but also has simple manufacturing process and strong practicability. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a biomimetic design diagram of the two biomimetic chiral energy absorption cores.

[0032] Figure 2 The overall schematic diagram of the automobile energy absorption box of the present application.

[0033] Figure 3 The structural schematic diagram of the two kinds of bionic chiral energy absorption cores of the present application.

[0034] Figure 4 The schematic diagram of the core front end structure cell of the present application.

[0035] Figure 5 The schematic diagram of the core rear end structure cell of the present application.

[0036] The reference signs in the present application are as follows:

[0037] 1, fixed plate, 2, energy absorption box shell;

[0038] 31, core front end structure, 311, outer chiral structure, 312, square box, 313, cylindrical rod, 314, core front end structure cell;

[0039] 32, core rear end structure, 321, negative Poisson's ratio honeycomb structure, 322, positive Poisson's ratio honeycomb structure, 323, chiral connection structure, 324, core rear end structure cell. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0041] Embodiment one: please refer to Figure 2 The present embodiment discloses an automobile energy absorption box, which comprises two fixed plates 1, an energy absorption box shell 2 and two kinds of bionic chiral energy absorption cores.

[0042] The fixed plate 1 is made of a rectangular aluminum alloy plate by numerical control milling, and the plate thickness is designed to be 10 mm. The fixed plate 1 is provided with bolt holes at four corners, one of the fixed plates 1 is connected with the bumper of the automobile through bolts, and the other fixed plate 1 is connected with the longitudinal beam of the automobile body through bolts.

[0043] The energy absorption box shell 2 is made of an extrusion forming process, and the thickness is 10 mm. The two ends of the energy absorption box shell 2 are connected with the two fixed plates 1 through welding respectively. A polyfluoroethylene anticorrosive coating is sprayed at the welding position, and the thickness of the coating is 5 μm, so as to ensure the corrosion resistance and connection reliability.

[0044] Please refer to Figure 1According to the scanning electron microscope image of the front leg of mantis shrimp, it can be found that the spiral chiral characteristics are presented, and the front and rear structural distribution has hierarchical structure characteristics. Therefore, according to the bionic negative Poisson's ratio characteristics and hierarchical structure characteristics of the hard front leg of mantis shrimp, two kinds of bionic chiral energy absorption cores are designed, and the two kinds of bionic chiral energy absorption cores are filled into the front end and the rear end inside the energy absorption box shell 2 respectively to form a multi-stage energy absorption.

[0045] Chirality refers to the characteristic that an object cannot coincide with its mirror image. Due to its unique geometric configuration, the chiral structure can realize uniform energy dissipation through rotation and deformation when impacted, thereby effectively reducing the initial peak force and avoiding stress concentration.

[0046] Please refer to Figure 3 The two kinds of bionic chiral energy absorption cores are the core front end structure 31 and the core rear end structure 32. The fixed plate 1, the energy absorption box shell 2, the core front end structure 31, and the core rear end structure 32 are all made of aluminum alloy and are plated with an anodic oxide film with a thickness of ≥10 μm to prolong the service life.

[0047] Please refer to Figure 2 and Figure 3 The core front end structure 31 and the core rear end structure 32 are filled into the front end and the rear end inside the energy absorption box shell 2 respectively.

[0048] Please refer to Figure 4 The core front end structure 31 is formed by an array of core front end structure cells 314, and the core front end structure cell 314 as a whole is surrounded by an outer structure and an inner structure. The outer structure is connected by six outer chiral structures 311, and the six outer chiral structures 311 are connected in the shape of a cube, which is equivalent to replacing the six planes of the cube with outer chiral structures 311 respectively. The center of the outer chiral structure 311 is a circular ring with an inner diameter of 9.6 mm and an outer diameter of 13.2 mm. The outer side of the circular ring is uniformly connected with four rod bodies, which are tangent to the circular ring. The adjacent rod bodies are spaced at the same angle, and the size of the rod body is 29 mm × 1.8 mm × 2.2 mm. The end of the rod body in each outer chiral structure 311 is connected with the end of the rod body of the other two adjacent outer chiral structures 311, and the connection of every three rod bodies forms the vertex of the outer chiral structure 311.

[0049] The center of the inner structure of the core front end structure cell 314 is a square box body 312, and the thickness of the edge of the square box body 312 is 1.8 mm. The six faces of the square box body 312 are respectively opposite to the circular rings of the six outer chiral structures 311. Each circular ring and the face of the square box body 312 opposite to it are fixedly connected by four cylindrical rods 313, and the cylindrical rods 313 are connected at the center points of the edges of the square box body 312. The cylindrical rods 313 are perpendicular to the edges of the square box body 312, and the diameter of the cylindrical rods 313 is 1.8 mm.

[0050] The inside of each face of the square box 312 is connected with a cross structure, which is composed of two circular rods with a diameter of 1.8 mm, and the end points of the cross structure are connected with the center of each edge of the square box 312.

[0051] For the core front-end structure cell 314, the outside chiral structure 311 has a negative Poisson's ratio characteristic, the square box 312 and the cylindrical rod 313 have a positive Poisson's ratio characteristic, when impacted, the outside outside chiral structure 311 first shrinks and twists, at the same time, the cylindrical rod 313 and the square box 312 expand, realizing the cooperative deformation of positive and negative Poisson's ratio structures to absorb impact energy.

[0052] Please refer to Figure 5 The core rear-end structure cell 324 is surrounded by an outside structure and an inside structure. The outside structure of the core rear-end structure cell 324 is a negative Poisson's ratio honeycomb structure 321, which includes two symmetrical and parallel sides, and the same side of the two sides is connected by two connected inclined surfaces, and the two inclined surfaces are inclined inward. The two sides of the negative Poisson's ratio honeycomb structure 321 and the inclined surfaces connected thereto form four corners. The overall size of the negative Poisson's ratio honeycomb structure 321 is 50mmx50mmx80mm, and the thickness of the side and the inclined surface is 3mm.

[0053] The inside structure of the core rear-end structure cell 324 is a positive Poisson's ratio honeycomb structure 322, and the outside of the positive Poisson's ratio honeycomb structure 322 is a cylindrical body with an outer diameter of 15mm. The center of the cylindrical body is a regular hexagonal cavity with a side length of 4mm.

[0054] The negative Poisson's ratio honeycomb structure 321 and the positive Poisson's ratio honeycomb structure 322 are connected by a chiral connecting structure 323, which is a negative Poisson's ratio structure. Specifically, the chiral connecting structure 323 is composed of four flat plates, one end of the four flat plates is tangent to the outside of the cylindrical body, the adjacent flat plates are spaced at the same angle, and the other end of the four flat plates is connected with the four corners of the negative Poisson's ratio honeycomb structure 321, respectively.

[0055] The core rear end structure 32 is formed by an array of core rear end structure cells 324, preferably, the intersection of adjacent core rear end structure cells 324 inside forms a positive Poisson's ratio honeycomb structure. Specifically, the shape at the top corner of the negative Poisson's ratio honeycomb structure 321 inside is a quarter honeycomb unit, and four quarter honeycomb units are spliced together to form a complete honeycomb structure. In this embodiment, the complete honeycomb structure is a regular hexagon with a side length of 5.4 mm. Through the design of the intersection of the core rear end structure cells 324 forming a positive Poisson's ratio honeycomb structure, a positive and negative Poisson's ratio staggered structure is further formed, and the positive and negative Poisson's ratio structures cooperate to absorb impact energy, realize energy dissipation in multiple deformation modes, and improve the stability of energy dissipation.

[0056] For the core rear end structure cell 324, the negative Poisson's ratio honeycomb structure 321 on the outside has a negative Poisson's ratio characteristic, the positive Poisson's ratio honeycomb structure 322 on the inside has a positive Poisson's ratio characteristic, and the chiral connecting structure 323 has a negative Poisson's ratio characteristic. When impacted, the negative Poisson's ratio honeycomb structure 321 on the outside first shrinks and deforms, driving the chiral connecting structure 323 to further shrink, and the positive Poisson's ratio honeycomb structure 322 twists and deforms, and when shrunk to a certain extent, the positive Poisson's ratio honeycomb structure 322 begins to expand, finally realizing multiple energy dissipation.

[0057] The working principle of the automobile energy absorption box is as follows:

[0058] When the automobile is impacted, the impact energy first acts on the front fixed plate 1, and the fixed plate 1 transmits the energy to the core front end structure 31. The outer chiral structure 311 produces a torsional shrinkage deformation along the center ring, the cylindrical rod 313 realizes energy transmission, and the cylindrical rod 313 and the square box 312 are crushed under the action of the impact force, extruding the outer chiral structure 311 and realizing energy absorption.

[0059] When the core front end structure 31 is completely crushed, the impact force is transmitted to the core rear end structure 32. First, the negative Poisson's ratio honeycomb structure 321 on the outside begins to shrink and deform, driving the chiral connecting structure 323 to twist and deform. The chiral connecting structure 323 also has a negative Poisson's ratio characteristic. When the negative Poisson's ratio honeycomb structure 321 and the chiral connecting structure 323, both of which have a negative Poisson's ratio, are shrunk, they will extrude the positive Poisson's ratio honeycomb structure 322, which will begin to expand, realizing multi-stage absorption of impact energy.

[0060] Finally, the residual impact force after multiple deformations, multiple energy dissipations, and multiple force transmission paths dissipations is smoothly transmitted to the vehicle body longitudinal beam through the rear fixed plate 1, effectively reducing the peak collision force and avoiding the passenger compartment from being subjected to a severe impact, thereby achieving the passive safety protection goal. Embodiment

[0061] The embodiment discloses a preparation method of an automobile energy absorption box, and is used for preparing the automobile energy absorption box as described in the embodiment one, and comprises the following steps:

[0062] Step one, two kinds of bionic chiral energy absorption core models are established according to the spiral chiral characteristics of mantis shrimp forelegs, and the two kinds of bionic chiral energy absorption cores comprise a core front end structure 31 and a core rear end structure 32.

[0063] Step two, the two kinds of bionic chiral energy absorption core models established in step one are introduced into three-dimensional printing software, and the forming of the two kinds of bionic chiral energy absorption cores is completed by using selective laser melting (SLM) technology. In the process, the laser power is 300 W, the scanning speed is 1000 mm / s, the layer thickness is 0.03 mm, the preheating temperature is 200 ℃, and annealing treatment is performed after forming.

[0064] Step three, the two kinds of bionic chiral energy absorption cores in step two are filled into the energy absorption box shell 2, the core front end structure 31 is filled into the front end of the energy absorption box shell 2, and the core rear end structure 32 is filled into the rear end of the energy absorption box shell 2.

[0065] Step four, the two fixing plates 1 and the energy absorption box shell 2 are welded, and the welding places are sprayed with a polyfluoroethylene anticorrosive coating, and the coating thickness is 5 μm, thus the preparation of the automobile energy absorption box is completed.

[0066] The bionic chiral energy absorption core in the energy absorption box is formed by using SLM technology once, which avoids the defects caused by the manufacturing and assembly of the energy absorption box, improves the reliability and durability of the energy absorption box, and the structure of the energy absorption box is layer by layer connected, which can ensure the self-supporting in the 3D printing process, reduce the demand for support materials in the printing process, thereby improving the efficiency, saving materials and improving the surface quality.

[0067] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limited. The present application has been described in detail with reference to the preferred embodiments, and those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, which should be covered in the scope of the present application.

Claims

1. An automotive energy absorbing box comprising: Two fixed plates (1) and energy absorption box shell (2), the two ends of energy absorption box shell (2) are fixedly connected with the two fixed plates (1), characterized by further comprising two kinds of bionic chiral energy absorption core, the bionic chiral energy absorption core is filled into the inside of energy absorption box shell (2), the two kinds of bionic chiral energy absorption core are core front end structure (31) and core rear end structure (32) respectively; The core front end structure (31) is formed by the array of core front end structure cells (314), and the core rear end structure (32) is formed by the array of core rear end structure cells (324); The core front end structure cell (314) and the core rear end structure cell (324) are both surrounded by an outer structure and an inner structure, the outer structure is a negative Poisson's ratio structure, and the inner structure is a positive Poisson's ratio structure; The outer structure of the core front end structure cell (314) is connected by six outer chiral structures (311), the six outer chiral structures (311) are connected in the shape of a square, the center of the inner structure of the core front end structure cell (314) is a square block (312), and the square block (312) and the outer chiral structure (311) are fixedly connected through a cylindrical rod (313); The center of the outer chiral structure (311) is a circular ring, four rod bodies are connected to the outside of the circular ring, the rod bodies are tangent to the circular ring, the angles between adjacent rod bodies are the same, and the end portions of the rod bodies in each outer chiral structure (311) are connected to the end portions of the rod bodies of the other two adjacent outer chiral structures (311); The six faces of the square block (312) respectively face the circular rings of the six outer chiral structures (311), each circular ring and the face of the square block (312) facing it are fixedly connected through four cylindrical rods (313), and the cylindrical rods (313) are connected to the centers of the edges of the square block (312); The outer structure of the core rear end structure cell (324) is a negative Poisson's ratio honeycomb structure (321), the inner structure is a positive Poisson's ratio honeycomb structure (322), the negative Poisson's ratio honeycomb structure (321) and the positive Poisson's ratio honeycomb structure (322) are connected through a chiral connecting structure (323), and the chiral connecting structure (323) is a negative Poisson's ratio structure; The negative Poisson's ratio honeycomb structure (321) comprises two symmetrical and parallel side faces, and the same side of the two side faces is connected through two connected inclined faces, and the two inclined faces are inclined inwardly; The outer side of the positive Poisson's ratio honeycomb structure (322) is a cylindrical body, and the center of the cylindrical body is a regular hexagonal cavity; The chiral connecting structure (323) is composed of four plates, one end of the four plates is tangent to the outer side face of the cylindrical body, the angles between adjacent plates are the same, and the other end of the four plates is connected to the end portions of the two side faces of the negative Poisson's ratio honeycomb structure (321).

2. The automotive energy absorbing box of claim 1, wherein, The inside of each face of the square block (312) is connected with a cross structure, the cross structure is composed of two circular rods, and the end points of the cross structure are connected to the centers of each edge.

3. The automotive energy absorbing box of claim 1, wherein, The intersection of adjacent core rear end structure cells (324) in the core rear end structure (32) forms a positive Poisson's ratio honeycomb structure.

4. The automotive energy absorbing box of claim 1, wherein, The fixed plate (1), the energy absorption box shell (2), the core front end structure (31) and the core rear end structure (32) are all made of aluminum alloy and plated with an anodic oxidation film.

5. A method of manufacturing the energy absorbing box of any one of claims 1-4, characterized in that, The method comprises the following steps: Step one, two kinds of biomimetic chiral energy absorption core models are established according to the helical chiral characteristics, and the two kinds of biomimetic chiral energy absorption cores comprise a core front end structure (31) and a core rear end structure (32); Step two, the two kinds of biomimetic chiral energy absorption core models established in step one are imported into a three-dimensional printing software, and a selective laser melting technology is adopted to complete the forming of the two kinds of biomimetic chiral energy absorption cores; Step three, the two kinds of biomimetic chiral energy absorption cores in step two are filled into an energy absorption box shell (2); Step four, a fixed plate (1) is welded with the energy absorption box shell (2), and the preparation of the automobile energy absorption box is completed.

6. The method of claim 5, wherein the method further comprises the step of: The two kinds of biomimetic chiral energy absorption cores in step two are subjected to annealing treatment after being formed.

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