Double-layer pyramid interlayer energy absorption structure for vehicle

Abstract

The invention relates to a double-layer pyramid interlayer energy absorption structure for an automobile, and relates to the field of automobile passive safety protection. Comprising an interlayer panel and a sandwich, the sandwich panel and the sandwich core adopt epoxy resin as an adhesive; the interlayer panel is made of a carbon fiber reinforced composite material and comprises four layers of carbon fiber plates, each layer of carbon fiber plate is formed by laying three layers of carbon fiber layers, the thickness of each layer of carbon fiber plate is the same, and the laying angle of each layer of carbon fiber plate can be freely designed. The sandwich structure is low in initial peak force, excellent in energy absorption performance and stable in deformation mode, the defects of a traditional sandwich structure in the aspects of specific energy absorption, light weight level, total energy absorption capacity and deformation stability are overcome, and therefore impact damage to passengers is reduced to the maximum extent when a vehicle collides.

Description

Technical Field

[0001] This invention relates to the field of automotive passive safety protection, specifically a double-layer pyramid sandwich energy-absorbing structure for vehicles. Background Technology

[0002] In recent years, with the rapid development of the automotive industry, the number of road traffic accidents has continued to increase, leading to a year-on-year rise in the casualty rate. Improving vehicle safety performance has become increasingly urgent. As an important component of the automotive safety system, passive safety performance mainly refers to the vehicle's ability to absorb impact energy through the plastic deformation of the vehicle body structure during a collision, thereby reducing the impact load on occupants. During a car collision, an excellent energy-absorbing structure can effectively absorb kinetic energy and mitigate impact loads. Although various structures and materials are currently used in vehicle body sandwich structures, traditional sandwich structures still have certain limitations in terms of mechanical performance, functional integration, and manufacturing processes.

[0003] The sandwich structure disclosed in CN106891598A is made of carbon steel, stainless steel, magnesium alloy, aluminum alloy, titanium alloy or load-bearing material. It is a corrugated sandwich structure that effectively improves specific strength and specific stiffness. However, the upper and lower panels of this corrugated sandwich structure are easily debonded when subjected to impact, and the stability of energy absorption is difficult to guarantee.

[0004] The sandwich structure manufacturing method disclosed in CN108656641A introduces initial defects, resulting in weak energy absorption capacity, insufficient structural strength, and unreliable impact resistance.

[0005] Carbon fiber reinforced composites possess significant advantages such as high specific energy absorption, excellent lightweight properties, and high specific strength. However, they are sensitive to impact loads and prone to sudden catastrophic failure under dynamic impact. In contrast, metallic materials excel in deformation stability and ductility, but also have inherent limitations such as high self-weight and limited energy absorption efficiency per unit mass. Combining the two through rational structural design can achieve complementary and synergistic performance improvements, fully leveraging the combined advantages of the high energy absorption characteristics of composite materials and the stable deformation mechanism of metallic materials. Introducing prefabricated geometric designs into the structure can effectively control its buckling behavior and failure modes, thereby optimizing the structure's axial compressive load response and significantly improving its impact resistance and energy absorption efficiency. Therefore, it is essential to design and develop a novel sandwich structure that deeply integrates the advantages of the aforementioned materials and structures to achieve simultaneous improvement in energy absorption efficiency and impact resistance. Summary of the Invention

[0006] To address at least one of the technical problems in the background art, the present invention provides a sandwich structure with low initial peak force, excellent energy absorption performance and stable deformation mode, which solves the shortcomings of traditional sandwich structures in terms of specific energy absorption, lightweight level, total energy absorption capacity and deformation stability, thereby minimizing impact injury to occupants in the event of a vehicle collision.

[0007] To achieve the above objectives, the present invention provides a double-layer pyramid sandwich energy-absorbing structure for automobiles, comprising: a sandwich panel and a core; The sandwich panel and the core are bonded together with epoxy resin. The sandwich panel is made of carbon fiber reinforced composite material and includes four layers of carbon fiber plates. Each layer of carbon fiber plate is made up of three layers of carbon fiber layup with the same thickness. The laying angle of each layer of carbon fiber plate can be freely designed.

[0008] Furthermore, the angle of the carbon fiber layup on the sandwich panel is 0° in the positive direction of the x-axis, positive in the positive direction of the y-axis, and negative in the opposite direction, with a maximum angle of 90°.

[0009] Furthermore, the angles of the carbon fiber layups in the sandwich panel from top to bottom are successively 45 degrees. -45 45 -45 .

[0010] Furthermore, the sandwich panel includes an upper base plate and a lower base plate, and the core is bonded between the upper base plate and the lower base plate.

[0011] Furthermore, the sandwich panel is formed by winding T700 carbon fiber bundles pre-impregnated with 3234 epoxy resin.

[0012] Furthermore, the core is made of stainless steel and manufactured by 3D printing, and is designed as a double-layer pyramid structure.

[0013] Furthermore, the pre-designed double-layer pyramid structure of the sandwich core is generated by arranging identical unit cells. The length of the structural members is L, the width and thickness of the member cross-section are D, the length and height of the legs are T1 and T2, the tilt angle of the members is θ, and the height of the unit cell node position of the sandwich structure is a, the width is b, and the tilt angle of the members θ and the height of the legs T2 can be freely designed.

[0014] Furthermore, the sandwich core is composed of 13 periodically arranged unit cells, the length L of the structural rod is 15mm, the width and thickness D of the rod cross-section are 2mm, the length and height T1 of the support are 5mm, T2 are 2mm, the inclination angle θ of the rod is 45°, and the height a of the unit cell node position of the sandwich structure is 4mm and the width b is 2mm.

[0015] The beneficial effects of this invention are as follows: 1. Excellent energy absorption performance and significantly improved energy absorption capacity. This invention significantly improves the energy absorption performance of the structure by making double-layer improvements to the traditional pyramid sandwich structure and introducing vertical pillars and reinforcing ribs; it exhibits a wider plateau energy absorption zone during compression, and its unique dual-unit contraction deformation mode, together with the synergistic effect of vertical pillars and reinforcing ribs, makes the energy absorption process more stable and sufficient.

[0016] 2. High load-bearing capacity and significantly improved structural stability. Through a double-layer design and the introduction of reinforcing ribs, the out-of-plane compressive performance and overall stiffness of the sandwich structure are effectively improved, avoiding the instability that easily occurs in traditional structures during compression. The structure exhibits high load-bearing capacity and stable deformation modes under quasi-static compression, with a controllable structural failure mechanism and a smooth deformation process, making it suitable for protection requirements under high-load conditions.

[0017] 3. Significant weight reduction and outstanding energy absorption performance. The application of carbon fiber panels achieves significant weight reduction while maintaining high energy absorption. The introduction of carbon fiber not only reduces structural mass but also optimizes load distribution through rational ply design, further enhancing specific energy absorption. This gives the structure excellent lightweight and high-efficiency characteristics, making it particularly suitable for weight-sensitive transportation and protective equipment.

[0018] 4. Adjustable structural parameters and controllable, optimizable energy absorption performance. Key parameters such as leg size and angle significantly influence the structure's energy absorption behavior. Parameter analysis shows that a 2mm leg size achieves optimal energy absorption; increasing the leg angle extends the platform's energy absorption phase and improves total energy absorption. While the arrangement of carbon fiber panels has a relatively small impact, proper design can still reduce peak loads and enhance protection capabilities, providing a clear technical path for engineering optimization.

[0019] 5. Mature manufacturing process with industrialization potential. The selective laser melting (SLM) additive manufacturing technology used in this invention is mature and can achieve integrated molding of complex structures. The samples have high forming quality and good consistency, and have good engineering applicability and promotion prospects. It can be widely used in lightweight and protective structures such as automotive anti-collision beams, battery box protection, and door protection systems. Attached Figure Description

[0020] Figure 1 These are schematic diagrams of various structures in embodiments of the present invention; Figure 2 This is a schematic diagram of the cell arrangement in an example of the present invention; Figure 3 This is a schematic diagram of the layup angle on the sandwich panel of an example of the present invention; Figure 4 A schematic diagram of the unit cell that makes up the sandwich core; Figure 5 This is a schematic diagram of the manufacturing process of an example of the present invention; Figure 6 A finished product drawing of an embodiment related to the sandwich structure; Figure 7 Load-displacement curves and compression process diagrams of quasi-static axial compression experiments for sandwich structures, specifically specimens 1, 2, and 3. Figure 8 Compressed comparison diagram of simulation and experiment for relevant embodiments of sandwich structures; In the diagram: 1-Mezzanine panel; 2-Core. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0024] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0025] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0026] Example

[0027] To achieve the above objectives, such as Figures 1 to 3 As shown, the present invention provides a double-layer pyramid sandwich energy-absorbing structure for vehicles, comprising: a sandwich panel 1 and a core 2; The sandwich panel 1 and the core 2 are bonded together with epoxy resin. The sandwich panel 1 is made of carbon fiber reinforced composite material and comprises four layers of carbon fiber sheets. Each carbon fiber sheet consists of three layers of carbon fiber lay-up with the same thickness, and the laying angle of each carbon fiber sheet can be freely designed. Figure 4 (a) and Figure 4 As shown in (b), the angle of the carbon fiber layup on the sandwich panel 1 is 0° in the positive direction of the x-axis, positive in the positive direction of the y-axis, and negative in the opposite direction, with a maximum angle of 90°.

[0028] The technical solution is further optimized so that the angles of the carbon fiber layups in the sandwich panel 1 from top to bottom are 45 degrees. -45 45 -45 This layup method can effectively suppress the warping and deformation of sandwich panels, while improving buckling stability.

[0029] The technical solution is further optimized. The sandwich panel 1 includes an upper base plate and a lower base plate, and the core 2 is bonded between the upper base plate and the lower base plate.

[0030] The technical solution has been further optimized. The sandwich panel 1 is formed by winding T700 carbon fiber bundles pre-impregnated with 3234 epoxy resin, which achieves the effect of lightweighting.

[0031] To further optimize the technical solution, the sandwich core 2 is made of stainless steel and manufactured using 3D printing, with a pre-designed double-layer pyramid structure. It possesses advantages such as high strength and good ductility, and exhibits a positive interaction effect with the carbon fiber reinforcement material. This metal composite hybrid structure has a beneficial interactive effect on energy absorption and impact resistance.

[0032] To further optimize the technical solution, the double-layer pyramid structure of the sandwich core 2 is generated by the arrangement of identical unit cells, as shown in the schematic diagram of the unit cell arrangement. Figure 2 As shown, the length of the structural member is L (mm), the width and thickness of the member section are D (mm), the length and height of the support are T1 (mm) and T2 (mm), the inclination angle of the member is θ, and the height of the unit cell node of the sandwich structure is a (mm) and the width is b (mm). The inclination angle of the member θ and the height of the support T2 can be freely designed.

[0033] To further optimize the technical solution, the sandwich core 2 is composed of 13 periodically arranged unit cells. The length L of the structural rod is 15mm, the width and thickness D of the rod cross-section are 2mm, the length and height T1 of the support are 5mm, T2 are 2mm, the inclination angle θ of the rod is 45°, and the height a of the unit cell node of the sandwich structure is 4mm and the width b is 2mm.

[0034] The sandwich energy-absorbing structure of this embodiment was subjected to compression testing using a 200KN universal testing machine. Before the test, the specimen was placed in the center of the fixed platform. During the test, the compression head began to compress downwards at a loading speed of 4mm / min, with a total compression displacement of 15mm. The signal sensor on the compression head recorded and transmitted relevant data to the computer in real time. After the experiment, the relevant data was processed, and the specific energy absorption was found to be 8.26KJ / kg. Figure 5 It can also be observed that the load transition in this embodiment is relatively smooth, with good collision force efficiency, avoiding local stress concentration and sudden structural failure.

[0035] This invention uses epoxy resin as an adhesive to cure and bond the core to the carbon fiber panel. This adhesive cures at room temperature and can withstand a temperature range of -60°C to +120°C. Furthermore, the bonding process is simple, easy to use, and cures rapidly.

[0036] Figure 6 As shown in the relevant embodiments of the present invention, I and II in the left side view serve as comparative examples, III is a preferred example, and the right side... Figure 6 (a) Figure 6 (b) and Figure 6(c) shows the front view of each example, with the red circles representing the unit cells that make up each example. Structure III exhibits higher load-bearing capacity and superior performance, as well as better energy absorption performance. Compared to I and II, III has a wider energy absorption region. This is due to its unique two-unit structure, which tends to contract inward during compression. The synergistic effect of the vertical support columns and reinforcing ribs enhances the overall structural strength, enabling the structure to maintain a smooth and stable deformation mode during compression, thereby achieving excellent energy absorption characteristics.

[0037] Figure 7 (a) shows the load-displacement curves obtained by experiment III after three experiments. Figure 7 (b) shows that the curve increases linearly with increasing load, and when the displacement reaches 3.1 mm, the curve begins to increase slowly before reaching the maximum load. With increasing displacement, local buckling of the support legs occurs first, followed by large-scale deformation and torsion of the support legs. Subsequently, bending failure of the vertical support columns is observed. The building still maintains relatively high load-bearing strength to this day. As the diagonal support legs and vertical columns begin to bend to bear the external load, the curve moves along a relatively flat path, with delamination occurring after approximately 6 mm of displacement, resulting in a brief and slight drop in the force-displacement curve. After the peak load, a smoother load transition is observed in III, thus exhibiting better impact force efficiency and avoiding localized stress concentration and sudden structural failure.

[0038] Figure 8 The finite element model of the III sandwich structure and its deformation during compression experiments are shown. By comparing the deformation patterns in the experiments and simulations, it can be found that there are slight differences between the finite element model and the experimental model, but their trends are basically consistent. A comprehensive analysis of the deformation consistency during the quasi-static compression process demonstrates the reliability of the experimental results presented in this paper.

[0039] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A double-pyramid sandwich energy-absorbing structure for vehicles, characterized in that, The application relates to a sandwich panel (1) and a sandwich core (2). The sandwich panel (1) and the sandwich core (2) are bonded by epoxy resin. The sandwich panel (1) is made of carbon fiber reinforced composite material and comprises four carbon fiber plates, each of which is made of three carbon fiber layers and has the same thickness, and the laying angle of each carbon fiber plate can be freely designed. The angle of the carbon fiber layer on the sandwich panel (1) is 0 degrees in the positive direction of the x-coordinate axis, is positive in the positive direction of the y-coordinate axis, is negative in the opposite direction, and the maximum angle is 90 degrees.

2. A double-pyramid sandwich energy-absorbing structure for vehicles as claimed in claim 1, wherein, The sandwich panel (1) comprises an upper bottom plate and a lower bottom plate, and the sandwich core (2) is bonded between the upper bottom plate and the lower bottom plate.

3. A double-pyramid sandwich energy-absorbing structure for vehicles as claimed in claim 1 or 2, wherein, The sandwich panel (1) from top to bottom is 45 , -45 , 45 , -45 .

4. A double-pyramid sandwich energy-absorbing structure for vehicles as defined in claim 3, wherein The sandwich panel (1) is made of T700 carbon fiber bundles impregnated with 3234 epoxy resin.

5. A double-pyramid sandwich energy-absorbing structure for vehicles as defined in claim 1, wherein The sandwich core (2) is made of stainless steel material and is made by 3D printing, and is preset as a double-layer pyramid structure.

6. A double-pyramid sandwich energy-absorbing structure for vehicles as defined in claim 1, wherein The double-layer pyramid structure of the sandwich core (2) is generated by the same unit cell arrangement, the length of the structural rod is L, the width and thickness of the rod section are D, the length and height of the foot are T1 and T2, the inclination angle of the rod is theta, the height of the node position of the sandwich structure unit cell is a, the width is b, and the inclination angle theta of the rod and the foot height T2 can be freely designed.

7. A double-pyramid sandwich energy-absorbing structure for vehicles as defined in claim 6, wherein The sandwich core (2) is composed of 13 periodically arranged unit cells, the length of the structural rod L is 15 mm, the width and thickness of the rod section D are 2 mm, the length and height of the foot T1 are 5 mm, T2 is 2 mm, the inclination angle of the rod theta is 45 degrees, the height of the node position of the sandwich structure unit cell a is 4 mm, and the width b is 2 mm.

8. A double-pyramid sandwich energy-absorbing structure for vehicles as defined in claim 7, wherein ​

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