Elliptical conical foamed aluminum energy absorption structure suitable for multi-angle impact working condition

Abstract

The utility model relates to an elliptical conical foamed aluminum energy absorption structure suitable for a multi-angle impact working condition, which is characterized in that an AA6063T5 aluminum alloy elliptical conical pipe forms a shell, and an industrial-grade closed-cell foamed aluminum material with the density of 0.25-0.4 g / cm < 3 > is filled in the shell in a layered manner to form a gradient density energy absorption core. Under the working condition of axial impact, the gradient foamed aluminum realizes layer-by-layer transmission and absorption of impact load; under the lateral impact working condition of 0-30 degrees, the elliptical cross section structure is beneficial to tangential diffusion of impact energy, and local stress concentration and damage are relieved. The structure shows excellent energy management capability under a multi-angle impact condition through geometric shape optimization and multi-stage material combination. Multi-index evaluation based on an entropy weight method shows that the structure has lower peak breaking force and higher specific energy absorption capacity under axial and bias impact conditions, and has good engineering adaptability and safety guarantee potential.

Description

Technical Field

[0001] This utility model belongs to the field of vehicle safety technology, specifically relating to an energy-absorbing structure used in a collision protection system for special vehicles, and more specifically, to the design and application of an elliptical cone-shaped aluminum foam energy-absorbing structure suitable for multi-angle impact conditions. Background Technology

[0002] With the rapid development of the modern automotive industry, vehicle safety and lightweight design have become core research topics. Energy-absorbing structures play a crucial role in overall vehicle safety during collisions, absorbing and dissipating collision energy through material deformation, thereby reducing injury to occupants. In recent years, foamed metal, as an emerging material, has gradually gained widespread application in energy-absorbing structures due to its excellent energy absorption characteristics and lightweight advantages.

[0003] Aluminum foam is a typical material among foamed metals, possessing low density, excellent energy absorption capacity, and high specific strength. Upon impact, the unique porous structure of aluminum foam effectively absorbs energy through compression deformation, thereby reducing structural damage from the impact force. Furthermore, the lightweight properties of aluminum foam allow it to significantly reduce vehicle weight while meeting energy absorption requirements, contributing to improved fuel efficiency and reduced emissions. Therefore, aluminum foam has become an important research direction in the design of automotive collision energy-absorbing structures.

[0004] However, the design of traditional energy-absorbing structures is often limited to a single geometry and material distribution, failing to fully consider the randomness of various collision conditions in automobiles. Therefore, studying the geometry and material distribution of energy-absorbing structures has a significant impact on their comprehensive mechanical performance under different impact directions. For example, in axial impact, a reasonable material distribution should be able to rapidly absorb energy and reduce peak stress; while in lateral impact, the energy-absorbing structure needs to have better stress dispersion capabilities to avoid local stress concentration. Therefore, optimizing the structural design while ensuring energy absorption effectiveness and improving its comprehensive performance under multi-angle impact conditions has become a key challenge in the current design of energy-absorbing structures. Utility Model Content

[0005] (1) Technical problems to be solved

[0006] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide an energy-absorbing structure with excellent comprehensive energy absorption performance suitable for multi-angle impact conditions, and to solve the technical problem that the current energy-absorbing structure cannot simultaneously exhibit excellent comprehensive energy absorption effect under axial and lateral impact conditions.

[0007] (2) Technical solution

[0008] Based on the aforementioned problems, this invention proposes an elliptical conical aluminum foam energy-absorbing structure suitable for multi-angle impact conditions. This energy-absorbing structure, through its internal filling with gradient-density aluminum foam material, can gradually transfer and disperse impact forces under impacts from different directions. The elliptical cross-section design not only improves the structure's energy absorption capacity in lateral impacts but also effectively reduces the combined peak breaking force during axial and lateral impacts. Simultaneously, the gradient-density aluminum foam filling material further enhances energy absorption performance, thus exhibiting excellent comprehensive energy absorption performance under multi-angle conditions, providing a new approach for optimizing vehicle energy-absorbing structures.

[0009] Furthermore, the elliptical cone-shaped aluminum foam energy-absorbing structure suitable for multi-angle impact conditions includes aluminum foam filler, a metal tube, and an energy-absorbing structure base. The metal tube is fixed to the energy-absorbing structure base by welding, while the aluminum foam filler is firmly adhered to the inner wall of the metal tube by tube wall adhesive, ensuring the overall stability of the structure.

[0010] Furthermore, the aluminum foam filler is designed with a gradient density and is bonded together with epoxy resin. Compared to aluminum foam filler with uniform density, this structure exhibits a more uniform energy absorption capacity under axial impact conditions.

[0011] Furthermore, the metal tube is designed as an elliptical cone, with its major and minor radii gradually increasing from top to bottom, thereby enabling the energy-absorbing structure to have excellent comprehensive impact resistance under lateral impacts at different angles.

[0012] (3) Beneficial effects

[0013] Compared with existing energy-absorbing structures, the beneficial effects of this invention are as follows:

[0014] 1. This utility model, through the design of a gradient-varying aluminum foam filling material, can significantly improve the energy absorption efficiency of the energy-absorbing structure under axial impact, effectively alleviate the damage of impact force to the structure, and enhance the overall impact resistance of the structure.

[0015] 2. This utility model adopts an elliptical cone tube design with an elliptical cross section, which makes it exhibit better energy dispersion ability under lateral impact conditions at different angles, and enhances the comprehensive energy absorption effect of the energy absorption structure under multi-angle impact conditions.

[0016] 3. This utility model uses the entropy weight method to evaluate the comprehensive performance of the structure, proving that the elliptical cone energy-absorbing structure filled with gradient density aluminum foam has superior comprehensive energy absorption performance and exhibits stronger impact adaptability and energy absorption capacity under multi-angle impact conditions. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 This is a schematic diagram of an elliptical cone-shaped aluminum foam energy-absorbing structure suitable for multi-angle impact conditions according to this utility model.

[0019] Figure 2 This is a graph showing the mechanical properties of the metal tube material of this utility model.

[0020] Figure 3 This is a schematic diagram of the overall structure of this utility model under loading conditions in the case of multi-angle impact.

[0021] Figure 4 This is a schematic diagram of the compression test of the structure of this utility model, wherein (a) is the compression process of the cylindrical energy-absorbing structure without aluminum foam filling; (b) is a schematic diagram of the structure before and during the compression process; (e) is a cylindrical energy-absorbing structure filled with uniform aluminum foam; (d) is a schematic diagram of the structure before and during the compression process; and (c) is a schematic diagram of the test machine.

[0022] Figure 5 This is a three-quarter cross-sectional view of the elliptical cone-shaped energy-absorbing structure filled with gradient density aluminum foam of this utility model.

[0023] Figure 6 These are schematic diagrams of four energy-absorbing structures of this utility model, wherein (a) is a cylindrical energy-absorbing structure without aluminum foam filling; (b) is a cylindrical energy-absorbing structure filled with uniform aluminum foam; (c) is an elliptical cone energy-absorbing structure filled with uniform aluminum foam; and (d) is an elliptical cone energy-absorbing structure filled with gradient density aluminum foam.

[0024] Figure 7 These are front sectional views and top cross-sectional views of four energy-absorbing structures of this utility model, wherein (a) is a cylindrical energy-absorbing structure without aluminum foam filling; (b) is a cylindrical energy-absorbing structure filled with uniform aluminum foam; (c) is an elliptical cone energy-absorbing structure filled with uniform aluminum foam; and (d) is an elliptical cone energy-absorbing structure filled with gradient density aluminum foam.

[0025] In the attached diagram: 1 represents aluminum foam filler, and 111 represents 0.4 g / cm³. 3 The aluminum foam, 112, has a concentration of 0.37 g / cm³. 3 The aluminum foam, 113, has a concentration of 0.34 g / cm³. 3 The aluminum foam, 114, has a concentration of 0.31 g / cm³. 3 The aluminum foam, 115, has a concentration of 0.28 g / cm³. 3 The aluminum foam, 116, has a concentration of 0.25 g / cm³. 312 is aluminum foam, 13 is aluminum foam adhesive, 2 is pipe wall adhesive, 2 is metal pipe, 21 is cylindrical pipe, 22 is elliptical conical pipe, 3 is energy-absorbing structure base, and 4 is bolt hole. Detailed Implementation

[0026] like Figure 1 and Figure 5 As shown, this utility model provides an elliptical conical aluminum foam energy-absorbing structure suitable for multi-angle impact conditions. The cross-section of the elliptical conical tube 22 is elliptical, with a major radius of 50mm and a minor radius of 40mm. The elliptical conical tube 22 has an inclination angle of 80° and a height of 230mm. The elliptical conical tube 22 contains aluminum foam filler 1, with the density of the aluminum foam decreasing sequentially from top to bottom. The density of 111 is 0.4g / cm³. 3 The aluminum foam, 112, has a concentration of 0.37 g / cm³. 3 The aluminum foam, 113, has a concentration of 0.34 g / cm³. 3 The aluminum foam, 114, has a concentration of 0.31 g / cm³. 3 The aluminum foam, 115, has a concentration of 0.28 g / cm³. 3 The aluminum foam, 116, has a concentration of 0.25 g / cm³. 3 The aluminum foam is bonded together with polyurethane adhesive 12 to form aluminum foam filler 1. The aluminum foam filler 1 is bonded to the elliptical conical tube 22 with epoxy resin adhesive 13. The elliptical conical tube 22 is coaxially placed with the energy-absorbing structure base 3 and connected by welding. The energy-absorbing structure base 3 has four bolt holes 4 for fixing to the top of the car frame.

[0027] like Figure 6-7 As shown, (a) is a cylindrical energy-absorbing structure without aluminum foam filling, consisting of a cylindrical tube 21 and an energy-absorbing structure base 3 welded together. (b) is a cylindrical energy-absorbing structure filled with uniform aluminum foam, consisting of a cylindrical tube 21, aluminum foam filler 1, and an energy-absorbing structure base 3. The aluminum foam filler 1 has a concentration of 0.4 g / cm³. 3 The aluminum foam 111, cylindrical tube 21 and energy-absorbing structure base 3 are welded together, and cylindrical tube 21 and aluminum foam filler 1 are bonded together by tube wall adhesive 13. (c) is an elliptical cone-shaped energy-absorbing structure filled with uniform aluminum foam, consisting of elliptical cone tube 22, aluminum foam filler 1 and energy-absorbing structure base 3, the aluminum foam filler 1 being 0.4 g / cm³. 3 The aluminum foam 111, the elliptical conical tube 22 and the energy-absorbing structure base 3 are welded together, and the elliptical conical tube 22 and the aluminum foam filler 1 are bonded together by the tube wall adhesive 13.

[0028] In this invention, the outer metal tube 2 of the energy-absorbing structure is made of commercial AA6063T5 aluminum alloy with a wall thickness of t=2.0mm, a density ρ=2700kg / m3, and mechanical properties of Young's modulus E=69Gpa, Poisson's ratio μ=0.3, yield stress σe=138.7MPa, ultimate strength σm=170.7MPa, and characteristic stress σn=132.6MPa. To obtain its mechanical properties, a B557M sample was prepared according to ASTM standards, and the tensile test sample was obtained from a 2mm thick AA6063T5 aluminum plate cut by wire cutting. Figure 2 As shown, the stress-strain curves of the tensile specimens obtained by uniaxial static tensile testing on an MTS testing machine are displayed. All aluminum foam fillers 1 are industrial-grade closed-cell aluminum foam materials.

[0029] like Figure 6 The cylindrical energy-absorbing structure without aluminum foam filling was tested using a WDW-100 testing machine from Changchun Kexin Testing Instrument Co., Ltd. (Example data follows) Figure 4 (a) and (b); axial compression tests were conducted on cylindrical energy-absorbing structures filled with uniformly packed aluminum foam, elliptical conical energy-absorbing structures filled with uniformly packed aluminum foam, and elliptical conical energy-absorbing structures filled with gradient-density aluminum foam using the WAW-2000A testing equipment from Jinan Test Metal Group Co., Ltd., to study the energy absorption capacity of these structures. Figure 4 (d) and (e). The entire experiment was conducted in accordance with ISO 13314-2011 standard, with a constant rate of 10. -2 s -1 The stress-strain curve was obtained through an experiment. The bottom was fixed to a rigid base, while the top was subjected to vertical compression by a machine platform at a constant speed of 10 mm / min. The entire compression process lasted 16.1 min, with a displacement of 161 mm.

[0030] like Figure 6 and Figure 7 The finite element software Abaqus / Explicit was used to simulate all structures in order to obtain realistic mechanical data.

[0031] In the field of energy-absorbing structures, numerous evaluation standards have been established to assess their impact resistance, including Energy Absorption (EA), Specific Energy Absorption (SEA), and Peak Crushing Force (PCF). Specifically, EA measures the total amount of energy absorbed by a structure through plastic deformation, directly reflecting its energy buffering capacity; SEA focuses on the energy absorption performance per unit mass and is widely recognized as a more comprehensive and accurate indicator of a structure's energy absorption efficiency; PCF represents the peak crushing force during impact, revealing the ultimate load-bearing capacity of the structure.

[0032] The method for calculating energy absorption (EA) is as follows:

[0033]

[0034] Where d is the crushing distance and F is the crushing force. SEA can be calculated as:

[0035]

[0036] Where M is the mass of the material, and the larger the SEA value, the better the energy absorption capacity of the energy-absorbing structure. The PCF of the structure can be read from the stress-strain curve.

[0037] This invention introduces a new comprehensive crashworthiness evaluation index, ISEA, IPCF, and provides the following definitions:

[0038]

[0039]

[0040]

[0041]

[0042] in, and This indicates that at a specific impact angle α x / α k Energy absorption values ​​and peak crushing forces under (x=k=1, 2, 3, 4, ..., Nα), where Nα represents the total number of impact angles considered, such as... Figure 3 This invention uses impact angles of 0°, 5°, 10°, 15°, 20°, 25°, and 30° for testing and verification, with Nα set to 7. and This represents the weight value under each impact angle relative to the condition.

[0043] This invention utilizes the entropy weight method to determine the proportion of comprehensive crashworthiness performance evaluation. The entropy weight method, derived from information entropy theory, is an advanced tool for quantitatively analyzing the information content and relative importance of evaluation indicators. It can objectively reflect the variability and uncertainty of each indicator and is widely used in economics, engineering, and other fields. It typically involves calculating the information entropy Ej for each set of data, further deriving the weights Wi of each indicator, and forming an importance score Si to support multi-dimensional evaluation problems.

[0044] In this invention, fourteen indicators (SEA and PCF values ​​under seven collision angles) of the energy-absorbing structure were compared through experiments and simulations to evaluate its energy absorption performance, as shown in Table 1. The numerical results in Table 1 provide the basic data for entropy weight method analysis. In the safety design of automotive components, SEA and PCF are respectively used as key positive and negative indicators for measuring energy absorption performance, meaning that an ideal energy-absorbing structure must have both high SEA and low PCF values. Table 1 obtains the numerical results of the experimental tests of the energy-absorbing structure, where SEA is in J / kg and PCF is in kN. Table 2 obtains the information entropy Ej and weight Wj values ​​for each set of data based on the original data and entropy weight method theory. Table 3 reveals the conclusion of the entropy weight method analysis, namely, the ranking of the energy-absorbing structures: elliptical conical tube filled with gradient density aluminum foam > elliptical conical tube filled with uniform aluminum foam > cylindrical tube filled with uniform aluminum foam > cylindrical tube without aluminum foam. This clearly indicates that the elliptical conical energy-absorbing structure filled with gradient density aluminum foam exhibits the best overall crashworthiness under multi-angle collision conditions. This invention emphasizes the key role of foam filling, elliptical cross-sectional shape, and elliptical cone with a moderate tilt angle in the optimization of energy-absorbing structures.

[0045]

[0046]

[0047]

[0048] Furthermore, it should be noted that the elliptical cone-shaped aluminum foam energy-absorbing structure designed in this utility model, which is suitable for multi-angle impact conditions, can have its specific density parameters varied according to the application conditions, and its thickness can also be increased or decreased as needed.

[0049] The elliptical cone energy-absorbing structure designed using this technical method, applied to the structural design of special vehicles, achieves a dual comprehensive optimization effect under both axial and lateral impacts by filling it with gradient-density aluminum foam. In axial impacts, this structure effectively reduces the instantaneous transmission of impact force, prolonging the energy absorption process and thus reducing the risk of structural damage. Under lateral impacts, the special design of the elliptical cross-section gives it higher resistance to deformation, improving overall structural stability and energy absorption efficiency. Using this evaluation method, namely the entropy weight method, the energy absorption performance of the filling material under various impact conditions is comprehensively evaluated, ensuring the scientific rigor and accuracy of the evaluation process. This method effectively balances the energy absorption performance in different impact directions, providing precise performance feedback, ultimately optimizing the design scheme, improving the overall performance of the energy-absorbing structure, and contributing to enhanced vehicle collision safety.

Claims

1. An elliptical cone-shaped aluminum foam energy-absorbing structure suitable for multi-angle impact conditions, characterized in that, The system includes aluminum foam filler (1), a metal tube (2), and an energy-absorbing structural base (3). The metal tube (2) is welded to the energy-absorbing structural base (3). The metal tube (2) is made of AA6063T5 aluminum alloy and its cross-section is designed as an elliptical cone tube (22). The major radius of the ellipse at the bottom of the ellipse tube (22) is 50 mm, the minor radius is 40 mm, the inclination of the cone is 80°, the height is 230 mm, and the wall thickness is 2.0 mm. The aluminum foam filler (1) is fixed to the inner wall of the metal tube (2) and bonded together with a tube wall adhesive (13). The aluminum foam filler (1) is industrial-grade closed-cell aluminum foam with a gradient density from top to bottom of 0.4 g / cm³. 3 0.37g / cm 3 0.34g / cm 3 0.31g / cm 3 0.28g / cm 3 and 0.25g / cm 3 It is composed of aluminum foam segments, and the segments of each density are bonded together by aluminum foam adhesive (12) to form a whole. It is used to realize the layer-by-layer transmission and dispersion of impact load under multi-angle impact conditions of 0-30°, and improve the overall energy absorption performance and impact resistance of the structure.

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