A bionic energy absorption box and a preparation method thereof
By designing a combination structure of a tubular outer shell and an internal bionic core for the bionic energy-absorbing box, the problem of local instability of existing energy-absorbing boxes under axial impact was solved, achieving stable and controllable progressive folding deformation and efficient energy absorption, thus improving the collision safety performance of automobiles.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUAIYIN INSTITUTE OF TECHNOLOGY
- Filing Date
- 2026-06-18
- Publication Date
- 2026-07-24
AI Technical Summary
Existing automotive energy-absorbing boxes are prone to local elastic instability under axial impact, generating excessive impact force, which affects the safety of occupants and the safety of the vehicle body structure.
A biomimetic energy-absorbing box is designed, which adopts a combination structure of a tubular shell and an internal biomimetic core. The tubular shell is inclined and has grooves on the side walls. The internal core adopts a variable cross-section single cell array with a functional gradient distribution along the axial direction. Through the synergistic effect of the macro shell and the micro core, the stress transmission path is reconstructed and stable and controllable progressive folding deformation is achieved.
It effectively avoids random structural instability, improves deformation stability and energy absorption efficiency, and achieves dynamic correction of lateral instability through a cross-scale shell-core coupling mechanism, providing stable platform force and continuous energy absorption capacity.
Smart Images
Figure CN122443347A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of automotive passive safety technology, and more specifically, to a biomimetic energy-absorbing box and its preparation method. Background Technology
[0002] With the rapid development of the automotive industry, vehicle collision safety performance has become a core indicator for measuring overall vehicle quality. In frontal collisions, the front bumper beam assembly is the first component to bear and transmit impact loads. The energy-absorbing box, a key buffer component installed between the bumper beam and the vehicle's longitudinal beams, efficiently converts enormous collision kinetic energy into deformation energy through its orderly and controllable plastic deformation, folding, collapse, or fracture. This maximizes the buffering of the impact force transmitted to the passenger compartment, protecting occupants' lives and preventing irreversible and severe damage to the main load-bearing structures such as the vehicle's longitudinal beams.
[0003] In existing technologies, traditional energy-absorbing boxes generally employ thin-walled metal tubular structures with cross-sectional shapes including circular, square, and polygonal. When these structures are subjected to axial impact, the load is completely converted into axial compressive stress on the tube wall, which can easily induce local elastic instability within a very short time, generating excessively high impact forces. This not only exacerbates the biomechanical damage to the occupants but also seriously endangers the safety of the main load-bearing structures such as the rear longitudinal beams. Summary of the Invention
[0004] In view of this, this application provides a biomimetic energy-absorbing box and its preparation method, which solves the problems of unstable deformation mode and low energy absorption efficiency of existing automotive energy-absorbing boxes.
[0005] The technical solution provided in this application is as follows: In a first aspect, this application provides a biomimetic energy-absorbing box, comprising an axially oriented tubular outer shell and a biomimetic core filled inside the tubular outer shell; The cross-sectional side length of the tubular shell increases continuously from both ends to the middle along the axial direction, forming a drum-shaped configuration with the smallest cross-sectional side length at both ends and the largest cross-sectional side length in the middle; the side wall of the tubular shell is inclined relative to the axis of the tubular shell to form a preset deviation angle α; The biomimetic core is composed of a periodically arrayed array of single cells; wherein the rods of the single cells are arc-shaped, and the diameter of the rods at the intersection nodes is larger than the diameter of the middle region; The bionic core is distributed along the axial direction in a functional gradient inside the bionic energy-absorbing box. From the front end to the rear end of the collision, the equivalent density or equivalent stiffness of the bionic core increases continuously.
[0006] In one possible implementation, at least one circumferentially extending groove is provided at the middle section of the side wall of the tubular shell, and the groove extends continuously in a closed loop along the circumference of the tubular shell.
[0007] In one possible implementation, the diameter of the member at the intersection node is made larger than the diameter of the middle region, so as to set a spherical or quasi-spherical reinforcement zone with increased diameter at the member intersection node to form a high-stiffness node.
[0008] In one possible implementation, the diameter of the single rod section of the single cell varies along the axial direction as a continuous function, decreasing and then increasing again.
[0009] In one possible implementation, the bionic core exhibits a continuously evolving mechanical performance functional gradient distribution along the axial direction inside the energy-absorbing box. The region near the collision front end has lower structural stiffness and density, forming a low-impedance front end region, while the region near the rear end connecting longitudinal beam has higher structural stiffness and density, forming a high-impedance rear end region.
[0010] In one possible implementation, the functional gradient distribution is achieved by changing the cross-sectional geometric parameters of the single-cell rod. From the collision front end to the rear end, the cross-sectional geometric parameters change continuously, causing the equivalent density or equivalent stiffness of the biomimetic core to evolve from low to high along the axial direction. The cross-sectional geometric parameters include the rod cross-sectional diameter and / or the normal offset compensation amount of the rod surface.
[0011] Secondly, this application provides a method for preparing the biomimetic energy-absorbing box according to any one of the first aspects, comprising: S1. A tubular shell blank is obtained, and the axial direction of the tubular shell is deviated by a preset angle α; S2. Construct a single-cell model; wherein, at the intersection of the rods in the single cell, there is a reinforced region with increased diameter, the diameter of the middle region of the rod is smaller than the diameter at the intersection of the rods, and the rod has an arc transition configuration; S3. Arrange the single-cell model constructed in S2 in a periodic array to generate a three-dimensional core model; use additive manufacturing process to integrally form the biomimetic core three-dimensional model to obtain the biomimetic core; S4. The bionic core obtained in S3 is placed inside the tubular outer shell obtained in S1 and fixedly connected to obtain the bionic energy-absorbing box.
[0012] In one possible implementation, S1 further includes: machining at least one circumferentially extending groove in the middle section of the side wall of the tubular shell by spinning or machining.
[0013] In one possible implementation, in S3, along the axial direction of the biomimetic core, from the front end to the rear end of the collision, the equivalent density or equivalent stiffness of the core is continuously increased by changing the cross-sectional geometric parameters of the single-cell rod, forming a functional gradient distribution along the axial direction; the cross-sectional geometric parameters include the diameter of the rod cross-section or the normal offset compensation amount of the rod surface.
[0014] In one possible implementation, a functional gradient distribution is formed along the axial direction, the method comprising: The normal offset compensation of the rods in a single cell is performed using a spatial field function. Along the axial direction from the front end of the collision to the rear end, the offset compensation amount increases continuously in a linear manner. In the front-end region of the collision, the normal offset compensation is set to a reference value, so that the front-end region of the collision maintains a low equivalent stiffness and material volume fraction, forming a low impedance region at the front end. In the rear-end region of the collision, the normal offset compensation is increased to a preset value within a preset range, so that the rear-end region of the collision obtains a higher equivalent stiffness and material volume fraction, forming a high impedance region at the rear end. The intermediate region is transitioned using linear interpolation.
[0015] Compared with the prior art, the technical solution provided in this application has the following beneficial effects: This application reconstructs the stress transmission path through the collaborative design of the macroscopic shell deviation angle and circumferential groove, effectively avoiding random structural instability and achieving stable and controllable progressive folding deformation. The nodal reinforcement of the internal biomimetic variable cross-section single cell and the mid-section thinning configuration form a "stress trap" effect, which transforms the stress into membrane stress and forces plastic deformation to concentrate in the flexible region to form a micro-plastic hinge, outputting a stable platform force and significantly improving deformation stability and energy absorption efficiency. At the same time, the macroscopic shell and the micro-gradient core construct a cross-scale shell-core coupling mechanism, dynamically correcting lateral instability, and the functional gradient distribution of the core along the axial direction realizes graded energy absorption and load-bearing capacity optimization matching throughout the collision stroke.
[0016] In addition, the "self-contact" friction and extrusion generated by the intense compression of the variable cross-section rod constitute a second energy dissipation pathway, further enhancing the overall energy absorption capacity; finally, the preparation process route combining traditional shell molding and additive manufacturing is clear and reliable, and suitable for industrial mass production. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of a biomimetic energy-absorbing box for automobiles provided in Embodiment 1 of this application.
[0018] Figure 2 This is a side view of a biomimetic energy-absorbing box for automobiles provided in Embodiment 1 of this application.
[0019] Figure 3This is an enlarged view showing the details of the variable cross-section configuration of a single cell provided in Embodiment 2 of this application.
[0020] Figure 4 This is a schematic diagram of the cross-sectional structure of the bionic core provided in Embodiment 1 of this application.
[0021] Figure 5 This is a flowchart illustrating a method for preparing a biomimetic energy-absorbing box, as provided in Embodiment 2 of this application.
[0022] Figure 6 This is a schematic diagram of the biomimetic design of the biomimetic energy-absorbing core provided in Embodiment 2 of this application.
[0023] Figure 7 This is a flowchart of a method for constructing a functional gradient distribution along the axial direction of a biomimetic core, as provided in Embodiment 2 of this application.
[0024] Explanation of reference numerals in the attached diagram: 1. Tubular outer shell; 2. Bionic core; 3. Groove; 4. High-rigidity node; 5. Pre-set flexible segment. Detailed Implementation
[0025] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0026] Example 1 See Figure 1 This is a schematic diagram of a biomimetic energy-absorbing box for automobiles provided in Embodiment 1 of this application. Figure 1 As shown, the energy-absorbing box includes a tubular outer shell 1 and a biomimetic core 2 filled inside the tubular outer shell 1.
[0027] The cross-sectional side length of the tubular outer shell 1 increases continuously from both ends to the middle along the axial direction, forming a drum-shaped configuration with the smallest cross-sectional side length at both ends and the largest cross-sectional side length in the middle. The sidewalls of the tubular outer shell 1 are inclined relative to the axis of the tubular outer shell 1 to form a predetermined deviation angle α.
[0028] In some embodiments, the tubular outer shell 1 is made of AA6061-T6 aluminum alloy, with a regular hexagonal cross-section, a wall thickness of 1.7 mm, an axial length of 160 mm, and a side length of 60 mm. The side length of the hexagon varies continuously along the axial direction, with the two ends having the smallest side length and the middle side length being the largest, causing the generatrix of the tube wall to form a predetermined deviation angle α relative to the axis, such as... Figure 2 As shown in the figure. Preferably, the value range of the above-mentioned deviation angle α is 5° < α < 10°.
[0029] Furthermore, such as Figure 2 As shown, at least one circumferentially extending groove 3 is provided at the midpoint of the sidewall of the tubular outer shell 1. The groove 3 works in conjunction with the aforementioned deviation angle α to reconstruct the stress transmission path, thereby achieving stress unloading and deformation guidance in the initial stage of the collision. In some embodiments, the groove 3 extends continuously in a closed loop along the circumference of the tubular outer shell 1, and the depth of the groove 3 is 4 mm. The axial width of the groove 3 is 13.16 mm. The groove 3 is located at the midpoint of the axial length of the tubular outer shell 1.
[0030] This application reconstructs the stress transmission path under collision load by combining the deviation angle design of the macro shell with the synergistic effect of the circumferential groove 3. It can actively guide the deformation initiation position in the early stage of collision, induce deformation to start from the groove 3 and gradually extend to both ends, effectively avoid random structural instability, and achieve a stable and controllable gradual folding deformation mode.
[0031] The aforementioned biomimetic core 2 is composed of a periodic array of single-cell units. The single-cell units adopt a variable cross-section rod topology to simulate the "mineralized node-tough fiber" coupling configuration at the microscopic level of a biomimetic eggshell.
[0032] Specifically, the rods in the single cell adopt a body-centered cubic structure. The geometry of the rods is an arc with a slight curvature, the radius of curvature of which is approximately three times the length of the rod, simulating the natural tension state of the tough fibrous membrane inside the eggshell. This arc transition configuration can more uniformly convert axial pressure into membrane stress along the curved surface of the rod, delaying the occurrence of macroscopic instability and forming a structural feature with elastic buffering capacity.
[0033] like Figure 3 As shown, the rods of the single cell employ a variable stiffness design. Spherical reinforcement regions are set at the intersection nodes of the cell rods. These thickened spherical or quasi-spherical reinforcement regions form high-stiffness nodes 4, simulating the papillary layer nodes of eggshell calcium deposition, thus improving the three-dimensional topological stability of the structure by increasing the node volume. The diameter of the middle region of the rods connecting the above nodes is thinned to form a pre-defined flexible segment 5. The diameter of the spherical reinforcement region is the maximum diameter at the node. D max , D max The diameter is 5mm. The diameter of the middle area of the connecting member is thinned, with a minimum diameter of 5mm. D min It is 2mm. D max / D min The ratio is 2.5, which is within the preferred range of 1.5 to 2.5.
[0034] In this embodiment, there is a significant structural stiffness gradient between the high-stiffness node 4 and the preset flexible segment 5. When an impact load is applied, the stress wave preferentially selects the path with lower stiffness, thereby being actively captured and confined in the thinning zone of the middle section of the member, so that the energy absorption path changes from disordered random instability to controlled orderly collapse.
[0035] Furthermore, the cross-sectional diameter D of a single member exhibits a continuous functional variation along the member's axial direction, decreasing and then increasing again, specifically following a sinusoidal transition. With the node center as the origin, extending along the member's axial direction, the cross-sectional diameter D gradually decreases from 5mm at the node to 2mm in the middle of the member, and then gradually increases to 5mm at the other node. This variable cross-section design enhances node stiffness, forcing plastic deformation primarily to occur in the flexible region of the member's middle, allowing each single cell to form an independent micro-plastic hinge, thereby macroscopically outputting a stable plateau force.
[0036] The mathematical expression for the change of the above continuous function is as follows:
[0037] In the formula, x Let the coordinates be along the axial direction of the member. L The total length of the member. D max The maximum diameter at the node. D min The minimum diameter of the middle section of the rod. n To control the positive real number of the curvature of the cross section, n ≥1. This function ensures a smooth and continuous transition of the cross-sectional diameter from the node to the middle section, eliminating stress concentration points and allowing stress to be smoothly captured and concentrated in the thinning zone of the middle section.
[0038] Furthermore, when single cells are periodically arrayed inside a hexagonal energy-absorbing box, the geometric features of the variable cross-section increase the contact area between adjacent cell rods after severe compression. The frictional work and compressive resistance generated by this self-contact constitute a second energy dissipation pathway in addition to the plastic deformation of the material.
[0039] like Figure 4 As shown, the aforementioned biomimetic core 2 exhibits a continuously evolving mechanical performance functional gradient distribution along the axial direction within the energy-absorbing box. The region near the impact front end has lower structural stiffness and density, forming a low-impedance front region. The region near the rear connecting longitudinal beam has higher structural stiffness and density, forming a high-impedance rear region. This gradient design is used to achieve wave impedance matching during the impact stroke.
[0040] Specifically, the aforementioned functional gradient distribution is achieved by altering the cross-sectional geometric parameters of the single-cell rods. These geometric parameters include the rod cross-sectional diameter and the normal offset compensation amount on the rod surface. From the collision front end to the rear end, the rod cross-sectional diameter and the normal offset compensation amount continuously increase, so that the equivalent density or equivalent stiffness of the biomimetic core 2 evolves from low to high along the axial direction.
[0041] Based on this, the working principle of the bionic energy-absorbing box provided in Embodiment 1 of this application is as follows: When a car is involved in a frontal collision, the impact load first acts on the front end of the energy-absorbing box, and the load is transmitted rearward along the axial direction of the energy-absorbing box. During this process, the macroscopic outer shell of the energy-absorbing box and the internal bionic core 2 work together to efficiently dissipate the collision kinetic energy in stages and regions.
[0042] In the initial stage of the collision, the deviation angle of the tubular outer shell 1 α First, it plays a crucial role. Due to the 5°~10° inclination angle of the tube wall generatrix relative to the axis, the tubular outer shell 1 has a drum-shaped configuration that is smaller at both ends and larger in the middle. When an axial impact force is applied to the tube end, the inclined tube wall converts part of the axial pressure into an outward radial component, causing the tube wall to exhibit a radial expansion tendency. This effect reduces the axial compressive stress component directly borne by the tube wall, while the radial expansion is constrained and supported by the internal core, forming a shell-core coupled synergistic load-bearing structure. This avoids the local elastic instability caused by the complete conversion of the load into axial compressive stress in traditional straight tube energy-absorbing boxes.
[0043] As the collision progresses, deformation gradually extends from the outer shell groove 3 towards both ends, resulting in stable, gradual folding deformation of the shell. During this process, the biomimetic core 2, filling the shell, begins to participate extensively in energy absorption. The variable cross-section design of the single cell within the core exhibits a stress trapping effect: under compressive loads, the nodal reinforcement regions of the cell members possess high local stiffness due to their large cross-sectional diameter and material volume, forming strong support points. In contrast, the cross-sectional diameter of the thinned region in the middle section of the member is only 1 / 2.5 to 1 / 1.5 of that at the nodal, significantly reducing local stiffness. When stress waves propagate within the member, they are actively guided to concentrate in the thinned region in the middle section, preventing plastic deformation from occurring in the stiffer nodal regions and instead "capturing" it in the pre-designed flexible region in the middle of the member.
[0044] After the mid-section thinning zone of each member reaches the yield limit, it forms an independent microplastic hinge. The member undergoes controlled bending deformation around this hinge point. During compression, the entire single cell exhibits an ordered deformation mode of progressive collapse from the center node to the corner node. A large number of single cells undergo the above-mentioned microplastic hinge deformation synchronously or sequentially in the periodic array, outputting a stable plateau force on the macroscopic force-displacement curve, avoiding the drastic force fluctuations caused by local instability in traditional structures.
[0045] In the later stages of the collision, the functional gradient distribution along the axial direction of the core begins to play a hierarchical energy absorption role. In the low-density region near the impact front, the cell members are thinner and have higher porosity, preferentially undergoing collapse deformation to buffer the impact with less reaction force. As deformation progresses rearward, the core density increases layer by layer, with each layer of cells participating in deformation energy absorption sequentially. In the high-density region near the longitudinal beam connection end, the cell members are thicker and have higher stiffness, only beginning to participate in large-scale energy absorption after the low-density region at the front has fully deformed, providing continuous and sufficient kinetic energy dissipation capacity for the later stages of the collision.
[0046] When a single unit cell is compressed to a compacted stage, the geometric characteristics of the variable cross-section rods result in numerous contacts between the rods of adjacent units. Because the rod cross-section varies axially, the contact between adjacent rods after deformation is not a simple point or line contact, but rather a surface contact. This self-contact generates significant frictional work, while the mutual compression between the rods also constitutes additional compressive resistance. This frictional work and compressive resistance, as a second energy dissipation pathway besides the plastic deformation of the material, further enhance the total energy absorbed by the energy-absorbing box.
[0047] Example 2 See Figure 5 This is a flowchart illustrating a method for preparing a biomimetic energy-absorbing box according to Embodiment 2 of this application. Figure 5 As shown, the specific implementation steps of the above method include: Step 1. Prepare a tubular shell blank 1 and make the axial direction of the tubular shell 1 produce a preset deviation angle α.
[0048] In this embodiment, aluminum alloy material is selected, and a tubular outer shell 1 with a regular hexagonal cross-section is obtained through extrusion molding or sheet metal roll welding. A predetermined deviation angle α is generated in the axial direction of the tubular outer shell 1 through bending or die stamping processes, with the deviation angle α ranging from 5° < α < 10°. Then, at least one circumferentially extending groove 3 is machined in the middle section of the side wall of the tubular outer shell 1 through spinning or machining, resulting in the energy-absorbing tubular outer shell 1.
[0049] Step 2. Construct a single-cell model; wherein, at the intersection of the rods in the single cell, there is a reinforced region with increased diameter, the diameter of the middle region of the rod is smaller than the diameter at the intersection of the rods, and the rods have an arc transition configuration.
[0050] like Figure 6As shown, a single-cell model is constructed using 3D modeling software based on the biomimetic eggshell microscopic "mineralized node-tough fiber" coupled configuration. At the junctions of the rods in the single cell, there are spherical or quasi-spherical reinforcement regions with increased diameter. The diameter of the middle region of the rods connecting the nodes is thinned and has an arc-shaped transition configuration. The cross-sectional diameter D of a single rod changes continuously along the axial direction, decreasing and then increasing again. The maximum diameter Dmax at the node connection is set to 1.5 to 2.5 times the minimum diameter Dmin of the middle region.
[0051] Step 3. Arrange the single cell model constructed in Step 2 in a periodic array to generate a three-dimensional core model; use additive manufacturing process to integrally form the above biomimetic core 2.
[0052] Specifically, the single-cell model constructed in step two is spatially arranged in a periodic array to generate a three-dimensional core model. Along the core axis, from the collision front end to the rear end, by changing the cross-sectional geometric parameters of the single-cell rods, the equivalent density or equivalent stiffness of the core is made to continuously increase, forming a functional gradient distribution along the axial direction. The aforementioned cross-sectional geometric parameters include the rod cross-sectional diameter and / or the normal offset compensation amount of the rod surface.
[0053] like Figure 7 As shown, the specific steps to make the equivalent density or equivalent stiffness of the core continuously increase to form a functional gradient distribution along the axial direction include: Step 301. Use the space field function to compensate for the normal offset of the rods in the single cell. Along the axial direction from the front end of the collision to the rear end, the offset compensation amount increases continuously in a linear manner.
[0054] In some embodiments, the initial core generated in step 2 is stiffened using a spatial field function. A linear mapping function Φ(z) along the axial height z is defined to drive an implicit operator to compensate for the normal offset of the single-cell rod. At the collision initiation point of z=0, the offset compensation amount is set as a baseline value to preserve the induced deformation sensitivity of the biomimetic variable cross-section rod. As the z value increases, the offset compensation amount increases linearly and continuously, reaching 0.5 mm at z=160 mm.
[0055] Step 302. In the collision front region, the normal offset compensation amount is set as the reference value, so that the collision front region maintains a low equivalent stiffness and material volume fraction, forming a low impedance front region.
[0056] Step 303. In the rear-end region of the collision, the normal offset compensation is increased to a preset value within a preset range, so that the rear-end region of the collision obtains a higher equivalent stiffness and material volume fraction, forming a high-resistivity rear-end region.
[0057] Step 304. The intermediate region is transitioned using linear interpolation.
[0058] Furthermore, selective laser melting or electron beam melting additive manufacturing processes are used to integrally form the three-dimensional model of the core to obtain the biomimetic core 2. Optionally, the selective laser melting parameters are: laser power 150~300W, scanning speed 600~1200mm / s, and layer thickness 20~50μm.
[0059] Step 4. Place the bionic core 2 obtained in Step 3 into the tubular outer shell 1 obtained in Step 1 and fix it in place to obtain the bionic energy-absorbing box.
[0060] Specifically, the bionic core 2 obtained in step 3 is placed inside the tubular outer shell 1 obtained in step 1, and the bionic core 2 and the tubular outer shell 1 are fixedly connected by means of interference fit, welding or gluing to obtain the finished bionic energy-absorbing box.
[0061] In another alternative implementation, to further enhance shell-core coupling and eliminate assembly interfaces, SLM technology can be used to achieve integrated molding of the shell and core, that is, to print the energy-absorbing box with macroscopic grooves 3 and functionally graded cores in one go, so that the shell and core form an interface-free metallurgical bond, maximizing the collision energy transfer efficiency.
[0062] Compared with the prior art, the technical solution provided in this application has the following beneficial effects: (1) This application reconstructs the stress transmission path under collision load by combining the deviation angle design of the macro shell with the synergistic effect of the circumferential groove 3. It can actively guide the deformation start position in the early stage of collision, effectively avoid random structural instability, and realize a stable and controllable progressive folding deformation mode.
[0063] (2) The core of this application adopts a variable cross-section single cell with a biomimetic eggshell microstructure. Its topological configuration of node strengthening, mid-section thinning and arc transition transforms the stress state of the rod during the collision from simple axial compressive stress to membrane stress distribution along the curved surface, delaying the occurrence of macroscopic instability and significantly improving the deformation stability and energy absorption efficiency of the structure.
[0064] (3) This application constructs a cross-scale shell-core coupling synergistic enhancement mechanism between the macroscopic shell and the microscopic core. The induced groove 3 of the shell pre-sets the macroscopic deformation phase, while the internal gradient cell dynamically corrects the lateral instability of the shell during the crushing process through its radial support force. The two work together to achieve precise matching of energy dissipation in the spatiotemporal dimension.
[0065] (4) The variable cross-section design of the single cell in this application has a "stress trap" effect. By artificially pre-setting the plastic deformation zone in the flexible zone in the middle of the rod, each single cell forms an independent micro-plastic hinge. The energy absorption path changes from disordered random instability to controlled orderly collapse, thereby outputting a stable platform force on a macroscopic scale and effectively buffering collision impact.
[0066] (5) The core of this application is functionally gradient distributed along the axial direction. The low-density area at the front end can induce progressive collapse and buffer the initial impact of the collision, while the high-density area at the rear end provides continuous structural support and kinetic energy absorption capacity, thus achieving an optimized match between energy absorption and load-bearing capacity throughout the entire collision process.
[0067] (6) After the variable cross-section unit cell of this application is severely compressed, the self-contact area between adjacent rods increases significantly. The resulting frictional work and extrusion resistance constitute a second energy dissipation path in addition to the plastic deformation of the material, further enhancing the overall energy absorption capacity.
[0068] (7) The preparation method of this application combines mature shell molding process with advanced additive manufacturing technology. The shell can be manufactured by traditional extrusion or roll welding process, and the internal gradient core can be integrally formed by selective laser melting or electron beam melting. The process route is clear and reliable and suitable for industrial mass production.
[0069] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A biomimetic energy-absorbing box, characterized in that, It includes an axially oriented tubular shell (1) and a biomimetic core (2) filled inside the tubular shell (1). The cross-sectional side length of the tubular shell (1) increases continuously from both ends to the middle along the axial direction, forming a drum-shaped configuration with the smallest cross-sectional side length at both ends and the largest cross-sectional side length in the middle; the side wall of the tubular shell (1) is inclined relative to the axis of the tubular shell (1) to form a preset deviation angle α; The biomimetic core (2) is composed of a periodically arrayed array of single cells; wherein the rods of the single cells are arc-shaped, and the diameter of the rods at the intersection nodes is larger than the diameter of the middle region; The bionic core (2) is distributed along the axial direction in the bionic energy-absorbing box with a functional gradient. From the front end to the rear end of the collision, the equivalent density or equivalent stiffness of the bionic core (2) increases continuously.
2. The biomimetic energy-absorbing box according to claim 1, characterized in that, At least one groove (3) extending circumferentially is provided in the middle section of the side wall of the tubular shell (1), and the groove (3) extends continuously in a closed loop along the circumference of the tubular shell (1).
3. The biomimetic energy-absorbing box according to claim 1, characterized in that, Make the diameter of the member at the intersection node larger than the diameter of the middle area, so as to set a spherical or quasi-spherical reinforcement zone with increased diameter at the member intersection node to form a high stiffness node (4).
4. The biomimetic energy-absorbing box according to claim 1, characterized in that, The diameter of the single rod section of the single cell varies along the axial direction as a continuous function, decreasing and then increasing again.
5. A biomimetic energy-absorbing box according to claim 1, characterized in that, The bionic core (2) has a continuously evolving mechanical performance functional gradient distribution along the axial direction inside the energy absorption box. The area near the front collision front has lower structural stiffness and density, forming a low impedance area at the front, while the area near the rear connecting longitudinal beam has higher structural stiffness and density, forming a high impedance area at the rear.
6. The biomimetic energy-absorbing box according to claim 1, characterized in that, The functional gradient distribution is achieved by changing the cross-sectional geometric parameters of the single-cell rod. From the front end to the rear end of the collision, the cross-sectional geometric parameters change continuously, so that the equivalent density or equivalent stiffness of the biomimetic core (2) evolves from low to high along the axial direction. The cross-sectional geometric parameters include the diameter of the rod cross-section and / or the normal offset compensation of the rod surface.
7. A method for preparing a biomimetic energy-absorbing box as described in any one of claims 1-6, characterized in that, include: S1. A tubular shell blank is obtained, and the axial direction of the tubular shell (1) is given a preset deviation angle α; S2. Construct a single-cell model; wherein, at the intersection of the rods in the single cell, there is a reinforced region with increased diameter, the diameter of the middle region of the rod is smaller than the diameter at the intersection of the rods, and the rod has an arc transition configuration; S3. Arrange the single cell model constructed in S2 in a periodic array to generate a three-dimensional core model; use additive manufacturing process to integrally form the three-dimensional bionic core model to obtain the bionic core (2). S4. The bionic core (2) obtained in S3 is placed inside the tubular shell (1) obtained in S1 and fixedly connected to obtain the bionic energy-absorbing box.
8. The method for preparing a biomimetic energy-absorbing box according to claim 7, characterized in that, The S1 further includes: machining at least one circumferentially extending groove in the middle section of the side wall of the tubular shell (1) by spinning or machining.
9. The method for preparing a biomimetic energy-absorbing box according to claim 7, characterized in that, In S3, along the axial direction of the bionic core (2), from the front end to the rear end of the collision, the equivalent density or equivalent stiffness of the bionic core (2) is continuously increased by changing the cross-sectional geometric parameters of the single-cell rod, forming a functional gradient distribution along the axial direction; the cross-sectional geometric parameters include the diameter of the rod cross-section and / or the normal offset compensation amount of the rod surface.
10. The preparation method according to claim 9, characterized in that, The method for forming a functional gradient distribution along the axial direction includes: The normal offset compensation of the rods in a single cell is performed using a spatial field function. Along the axial direction from the front end of the collision to the rear end, the offset compensation amount increases continuously in a linear manner. In the front-end region of the collision, the normal offset compensation is set to a reference value, so that the front-end region of the collision maintains a low equivalent stiffness and material volume fraction, forming a low impedance region at the front end. In the rear-end region of the collision, the normal offset compensation is increased to a preset value within a preset range, so that the rear-end region of the collision obtains a higher equivalent stiffness and material volume fraction, forming a high-impedance region at the rear end; the middle region is transitioned by linear interpolation.