A multi-tube combined energy absorbing device based on nested form and vehicle

Abstract

The present invention relates to the field of vehicle engineering, and discloses a multi-tube combined energy absorbing device and a vehicle based on a nested form. The energy absorbing device includes an anti-climber, multiple nested energy absorbing tubes, a thin-walled outer shell, and a rear end plate. The nested energy absorbing tubes are fixed to the rear end plate. The rear end plate is fixedly installed at the front end of the vehicle, and is fixedly provided with an outer shell around it. The outer shell surrounds the nested energy absorbing tubes, and an anti-climber is fixedly provided at the other end of the outer shell. The nested energy absorbing tubes include an outer tube and an inner tube, both of which have thin walls. The cross-sections of the inner and outer tubes are both square. The outer tube protrudes outward at a distance to form a reinforcement ring, and the inner tube is pre-set with multiple folds. The present invention provides a multi-tube combined energy absorbing device and a vehicle based on a nested form. The energy absorbing device has an outer reinforcement ring and inner pre-folds, which can increase the energy absorption of the structure while reducing the load fluctuation amplitude of the load curve.

Description

Technical Field

[0001] The present invention relates to the field of vehicle engineering technology, and in particular to a nested multi-tube combined energy absorbing device and a vehicle. Background Art

[0002] Vehicle front-end energy absorbers are the last line of defense for drivers and passengers in the event of a collision, making research into improving their energy absorption properties crucial. Thin-walled energy absorbers are gaining widespread application due to their simplicity, stable deformation patterns, and low manufacturing costs. As vehicle speeds and crashworthiness standards continue to increase, traditional thin-walled energy absorbers are becoming increasingly incapable of dissipating the increasing kinetic energy of collisions. Consequently, the development of high-performance modular energy absorbers has become a research hotspot.

[0003] At present, the research on combined energy absorption devices is mainly based on two ideas: the introduction of new components and the application of multi-tube combinations. The former mainly refers to the filling of functional materials and the design of internal structures. It has defects such as bottlenecks in improving energy absorption characteristics, complex structural forms, and high processing costs. The more common multi-tube combined energy absorption devices are simple applications of thin-walled pipes with the same configuration or only different heights. Due to the lack of a systematic collaborative design method, the load-displacement curves of each pipe will have a more obvious overlap, resulting in the initial peak and subsequent load fluctuations of the combined structure being significantly amplified. In order to achieve a significant increase in energy absorption while reducing the initial peak and load fluctuations of the combined structure as much as possible, how to separate the load-displacement curves of each pipe is the focus of multi-tube combination design. Summary of the Invention

[0004] In order to overcome the above technical problems, the purpose of the present invention is to propose a multi-tube combined energy absorption device and vehicle based on a nested form, which has a multi-tube combination with differentiated configurations, including inner and outer nested tubes with differentiated configurations, and the distribution of reinforcement rings and folds between different nested tubes is also differentiated. By comprehensively using the reinforcement ring configuration and the pre-fold configuration, the energy absorption characteristics of the single-tube structure are improved, and a multi-tube load curve staggered overlap mechanism is established to further reduce the initial peak and load fluctuation of the combined structure.

[0005] The present invention provides the following technical solutions:

[0006] First aspect

[0007] The present invention provides a multi-tube combined energy absorbing device based on a nested form, which comprises an anti-climber (1), a plurality of nested energy absorbing tubes (2), a thin-walled shell (3) and a rear end plate (4), wherein the nested energy absorbing tubes (2) are fixed on the rear end plate (4); the rear end plate (4) is fixedly installed on the front end of a vehicle, and is fixedly provided with a shell (3) on all four sides thereof, the shell (3) surrounds the nested energy absorbing tubes (2), and the anti-climber (1) is fixedly provided at the other end of the shell (3); the nested energy absorbing tubes (2) comprise an outer tube (21) and an inner tube (22) both having thin walls, and the cross sections of the inner and outer tubes are both square; the outer tube (21) protrudes outwards at intervals along the tube height direction to form a plurality of square annular reinforcement rings (23); a plurality of folds (24) are preset on the inner tube (21), and the folds (24) are arranged inwardly and outwardly at intervals.

[0008] In the above embodiment, the outer reinforcement ring and the inner pre-folds can increase the energy absorption of the energy absorbing device while reducing the load fluctuation amplitude of the load curve.

[0009] According to some embodiments, the parameters of the outer tube (21) include the initial height H and thickness t of the outer tube (21), wherein the height h of the reinforcing ring (23) is r and thickness t r , N r The outer tube (21) is divided into N r+1 regions, each with a height of R ij , wherein i is the serial number of the outer tube (21) or the inner tube (22), j is the serial number of each area of ​​the outer tube (21) or the inner tube (22); the parameters of the inner tube (22) include the side length L of the inner tube (22) ic , initial height H, thickness t, where the fold offset distance ΔP, ΔP = 0.5C ij tanΔθ,N f The inner tube is divided into N parts by the folds f regions, each with a height of C ij , N r and N f Satisfy the following formula:

[0010]

[0011]

[0012] L ic ≤L-2ΔP(3)

[0013] Where δ spis the theoretical half-wavelength of the wrinkles of the thin-walled square tube, I1(β0) and I3(β0) are the energy dissipation coefficients in the super-folding unit theory, L is the side length of the outer tube (21), and L ic is the side length of the inner tube (22).

[0014] According to some embodiments, the t of the reinforcing ring 23 r Satisfy the following requirements:

[0015] PFr≥Fr=MCF(4)

[0016]

[0017]

[0018] Where PF r is the ultimate load of the reinforcing ring 23, F r is the load applied by the outer tube (21) to the reinforcing ring (23), assuming that the maximum load value is MCF, MCF is the theoretical average load value of a traditional thin-walled square tube, and E is the Young's modulus of the thin-walled material used to manufacture the outer tube (21).

[0019] According to some embodiments, the offset distance ΔP of the fold (22) satisfies the following formula:

[0020] PF1≤PF1t(7)

[0021]

[0022]

[0023] Where A is the cross-sectional area of ​​the structure, σ0 is the flow stress of the material, PF1 is the initial theoretical peak load of the inner pre-corrugated tube, and PF 1t is the initial theoretical peak load of a traditional thin-walled square tube with the same number of folds, tube height, and tube thickness, and t is the inner tube wall thickness.

[0024] According to some embodiments, the basic moving distance ΔR of the outer tube (21) is determined according to the number N of the outer tubes (21). i , height H, number N of the reinforcing rings (23) r To confirm:

[0025]

[0026] According to some embodiments, the basic moving distance ΔC of the inner tube (22) is determined according to the number N of the inner tubes (22). i , height H, number N of the folds (23) f To confirm:

[0027]

[0028] Second aspect

[0029] The present invention also provides a vehicle comprising any of the above-mentioned multi-tube combined energy absorbing devices based on a nested form.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention provides a nested multi-tube combined energy absorbing device and vehicle. The energy absorbing device breaks the bottleneck of improving the energy absorption characteristics of existing energy absorbing devices, has a simple structure, low processing cost, and has an outer reinforcement ring and an inner pre-folded form, which can increase the energy absorption of the structure while reducing the load fluctuation amplitude of the load curve.

[0032] 2. By changing the relative positions of the reinforcing ring and the pre-fold, the load curves of different nested structures are fully and equidistantly separated, thereby effectively reducing the load fluctuation of the structure composed of multiple nested tubes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is an overall and exploded schematic diagram of Example 1 provided by the present invention.

[0034] Figure 2 Schematic diagram of the timing control method for peak load formation of inner and outer tubes according to the second embodiment of the present invention.

[0035] Figure 3 The second embodiment of the present invention provides a configuration alienation design method in which the inner and outer pipes have a height difference.

[0036] Figure 4 This is a schematic diagram of the process of determining the enhancement ring structure parameters of the second embodiment provided by the present invention.

[0037] Figure 5 This is a schematic diagram of the process of determining the fold offset distance in the second embodiment provided by the present invention.

[0038] Figure 6 This is a comparison chart of the energy absorption advantages of the traditional square tube nested structure in Example 1 provided by the present invention and this Example 1.

[0039] Figure 7 This is the load curve distribution of each pipe fitting after the height difference-variable configuration distribution design is introduced in the second embodiment provided by the present invention.

[0040] Figure 8 A comparison chart of the energy absorption characteristics of the traditional fixed-configuration distributed multi-tube structure provided by the present invention and the height difference-variable configuration multi-tube structure in Example 2.

[0041] The reference numerals in the accompanying drawings are:

[0042] Anti-climber 1; nested energy-absorbing tube 2; outer tube 21; inner tube 22; reinforcing ring 23; fold 24; outer shell 3; rear end plate 4. DETAILED DESCRIPTION

[0043] The present invention is described in detail below with reference to the embodiments and accompanying drawings. However, it should be understood that the embodiments and accompanying drawings are merely exemplary descriptions of the present invention and do not constitute any limitation on the scope of protection of the present invention. All reasonable variations and combinations within the scope of the inventive concept of the present invention fall within the scope of protection of the present invention.

[0044] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention. The terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In addition, unless otherwise expressly specified and limited, the terms "disposed", "installed", "connected", and "connected" should be understood in a broad sense. For example, they can be fixedly connected, detachably connected, or integrally connected; they can be mechanically connected or electrically connected; they can be directly connected or indirectly connected through an intermediate medium, or they can be internal communication between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] The present invention will be further described below with reference to the accompanying drawings.

[0046] Example 1

[0047] like Figure 1As shown, this embodiment provides a multi-tube combined energy absorbing device based on a nested form, which includes an anti-climber 1, multiple nested energy absorbing tubes 2, a thin-walled shell 3, and a rear end plate 4. The nested energy absorbing tubes 2 are fixed to the rear end plate 4, which is fixedly installed at the front end of the vehicle. The rear end plate 4 is fixed with a shell 3 around it, which surrounds the nested energy absorbing tubes 2. The anti-climber 1 is fixed to the upper part of the shell 3, and a gap is left between the nested energy absorbing tubes 2 and the anti-climber 1. The nested energy absorbing tubes 2 include an outer tube 21 with a thin wall and an inner tube 22 with a thin wall. In this embodiment, the cross-sections of the inner and outer tubes are both square. Along the height direction of the tube, the wall of the outer tube 21 protrudes outward at a certain distance to form a square ring-shaped reinforcement ring 23. The reinforcement ring 23 has a certain thickness. The reinforcement ring 23 divides the outer tube 21 of a single nested energy-absorbing tube 2 into multiple outer tubes. The materials of the reinforcement ring 23 and the outer shell 3 can be selected from thin-walled materials; the inner tube 22 is preset with multiple folds 24, and the multiple folds 24 divide the inner tube 22 into multiple inner tubes, wherein each nested energy-absorbing tube 2 has a different tube height and configuration distribution form (including a variable reinforcement ring distribution form and a variable fold distribution form). One end of the nested energy-absorbing tube 2 is fixed on the rear end plate 4, and the anti-climber 1 and the rear end plate 4 are surrounded by the outer shell 3 to improve the energy absorption stability of the overall energy absorption device.

[0048] Working process description:

[0049] like Figure 6 As shown, the nested energy-absorbing tube 2 with a nested tube structure provided in this embodiment can fully utilize the advantages of the reinforcement ring 23 to improve the structural energy absorption and the preset folds 24 on the inner tube to improve the orderliness of deformation. The nested structure can effectively improve the energy absorption while also effectively reducing the load curve fluctuation amplitude. Among them, the traditional square tube nested structure is that no configuration parameters are set for the inner and outer pipes of the same size, and the existing nested structure with preset reinforcement rings means that the inner and outer pipes of the same size are both provided with reinforcement ring configurations. In this embodiment, a reinforcement ring is set on the outer tube 21 and folds are set on the inner tube 22. In comparison, this embodiment has smaller load fluctuations. The form of the outer reinforcement ring and the inner pre-fold can increase the energy absorption of the structure while reducing the load fluctuation amplitude of the load curve.

[0050] Example 2

[0051] On the basis of the first embodiment, further, the inner and outer pipes are designed with height difference-variable configuration distribution, such as Figure 1 The outer tube 21 is a thin-walled tube, and a reinforcement ring 23 is preset on the outside thereof with a side length L or = 50mm, the initial height H of the outer tube 21 = 150mm, the thickness t = 2mm, where the height h of the reinforcement ring 23 r and thickness t r Both are 4mm. N rThe reinforcing rings 23 divide the outer tube 21 into N r +1 area, each area has a height of R ij , where i is the serial number of the pipe and j is the serial number of each area. The side length L of the inner pipe 22 ic =40mm, initial height H = 150mm, thickness t = 2mm, where fold offset distance ΔP = 1.5mm, ΔP = 0.5C ij tanΔθ. N f The inner tube is divided into N parts by the folds 24 f regions, each with a height of C ij (i is the serial number of the pipe fitting, j is the serial number of each area).

[0052] like Figure 2 .a external tube timing control and Figure 2 .b The timing control of the inner tube is based on the number of configurations N r =N f = 4 as an example, since the setting of the reinforcing ring 23 or the fold 24 can effectively control the macroscopic deformation mode of the structure, that is, each area R divided by the configuration parameter along the loading direction ij or C ij Deformation wrinkles will be formed one by one, and each deformation wrinkle will correspond to a displacement interval D on the load curve. sj It can be seen that by changing the enhancement ring r j and fold connection c j The relative position of the peak load in the subsequent displacement interval can change the distribution position of the peak load in the subsequent displacement interval. j and c j Moving in the positive direction of loading will cause the peak load of the subsequent displacement curve to shift backward accordingly, while moving in the negative direction will cause the peak load formation sequence to shift forward. Obviously, using this peak load formation timing control method can achieve sufficient staggered separation of the load-displacement curves of each tube in the multi-tube composite structure, thereby achieving perfect compatibility between high energy absorption and small load fluctuations.

[0053] like Figure 3 .a, the outer tube 21 is designed with height difference-variable configuration distribution, such as Figure 3 b. The inner tube 22 is designed with a height difference-variable configuration distribution. The inner tube 22 has inward and outward spaced folds 24, which protrude inward or outward for a certain distance. The height difference-variable configuration distribution design is used to make the deformation sequence of each inner and outer tube appear correspondingly spaced during loading, thereby achieving equidistant and sufficient separation of the load-displacement curves of each tube. ΔR and ΔC are the basic movement distances of the configuration, and ΔH p The end region R i1 and C i1The height difference introduced. The height difference is used to separate the initial peak load of each pipe, while the variable configuration distribution is used to separate the subsequent peak loads of each pipe. As can be seen from the figure, as the pipe number i gradually increases, the reinforcement rings and folds set on the inner and outer pipes will move downward, and the distribution position of the subsequent peak load of the pipe will also shift backward accordingly. By reasonably setting the movement distance of the two, it is possible to achieve sufficient offset and overlap of the load-displacement curves of each pipe. Therefore, this embodiment proposes a universal configuration differentiation design method for nested combination structures.

[0054] For the configuration-differentiated multi-tube combination structure, the number of reinforcement rings 23 outside the outer tube 21 is N. r , the number of folds N of the inner tube 22 f , the thickness t of the reinforcing ring 23 r , the height h of the reinforcing ring 23 r , fold offset distance ΔP, configuration base movement distance ΔR (ΔC) directly determine the misalignment of the load-displacement curve of each tube, which will significantly affect the energy absorption characteristics of the composite structure. Configuration number N r and N f It can be determined by the number of folds of traditional thin-walled square tubes at the same height:

[0055]

[0056]

[0057] L ic ≤L-2ΔP(3)

[0058] Where δ sp is the theoretical half-wavelength of the wrinkles of the thin-walled square tube, I1(β0) and I3(β0) are the energy dissipation coefficients in the super-folded unit theory, L is the side length of the outer tube 21, and L ic Is the side length of the inner tube 22. Since the outer tube can control the deformation mode of the inner tube, the number of folds on the inner tube is consistent with the number of reinforcing rings on the outer tube, that is, it is determined according to the side length of the outer tube. Figure 4 As shown in .a, if the outer tube 21 is to form deformation wrinkles between two adjacent reinforcing rings 23, the reinforcing rings 23 must have sufficient strength. According to the load-bearing conditions of the reinforcing rings 23, the thickness t can be adjusted by the stability of the pressure rod. r and height h r Solve. Figure 4 As shown in .b, for the convenience of processing, it is assumed that t r =h r When the thickness of the thin-walled pipe used to manufacture the reinforcement ring 23 is t = 2 mm, t r and h r It needs to be equal to 4 mm to meet the requirements of formula (4).

[0059] PFr≥Fr=MCF(4)

[0060]

[0061]

[0062] Where PF r is the ultimate load of the reinforcement ring 23, and MCF is the theoretical value of the average load of a traditional thin-walled square tube (Equation 2). The reinforcement ring material and the tube material are the same, that is, the two are integral, which is equivalent to the reinforcement ring portion being thicker and the non-reinforcement ring area being thinner.

[0063] like Figure 5 As shown, as the number of folds increases, the initial strength of the pre-corrugated inner tube 22 and the strength of the traditional thin-walled square tube (after the width is reduced) both show a downward trend. 1t The fold offset distance ΔP is solved by the initial theoretical strength PF1 of the pre-folded inner tube 22:

[0064] PF1≤PF1t(7)

[0065]

[0066]

[0067] Where A is the cross-sectional area of ​​the structure, σ0 is the flow stress of the material. PF1 is the initial theoretical peak load of the inner pre-corrugated tube, PF 1t is the initial theoretical peak load of the traditional thin-walled square tube under the same number of folds, tube height, and tube thickness, and t is the thickness of the thin-walled tube.

[0068] The basic moving distances ΔR and ΔC of the configuration can be adjusted according to the number of pipes N i , pipe height H, configuration number N r or N f To confirm:

[0069]

[0070]

[0071] Since one fold corresponds to two peak values ​​and two trough values, the value of ΔC in formula (11) is multiplied by 1 / 2 compared with formula (10).

[0072] According to formulas (1)-(11) and the initial structural parameters of the inner and outer pipes, the specific structural parameters of each pipe in the nested multi-pipe combination structure can be determined. The specific situation is shown in Table 1 (with the number of pipes N i =5 as an example).

[0073] Table 1 R of each inner and outer pipe fitting of nested structure ij (C ij )Region specific value

[0074]

[0075] Working process description:

[0076] like Figure 7 The distribution of the load-displacement curves of each pipe after the nested multi-tube structure introduces a height difference-variable distribution design. It can be clearly seen that all peak loads have been fully and equidistantly analyzed, which can maximize the purpose of staggered superposition of multi-tube load-displacement curves. Figure 8 The load-displacement curves of the nested multi-tube assembly before and after the introduction of the height-difference-variable configuration distribution design are further compared. It is clear from this that the configuration-differentiation design approach proposed in this embodiment achieves a good combination of excellent energy absorption characteristics, such as high energy absorption, low initial peak value, and minimal load fluctuation, significantly dissipating collision kinetic energy more smoothly. By varying the relative positions of the reinforcement ring and pre-folds, the load curves of the different nested structures are fully and equidistantly separated, effectively reducing load fluctuations in the structure composed of multiple nested energy-absorbing tubes 5.

[0077] In the above embodiment 2, only the working condition of combining five heterogeneous nested energy-absorbing tubes 2 for energy absorption is proposed. The five nested tubes have different distribution forms of the configuration (reinforcement ring or pre-fold) of the outer tube or inner tube of each nested tube. In other embodiments, the height H, thickness t, outer tube width L of each nested energy-absorbing tube 2 can be reasonably adjusted according to actual needs. or , Inner tube width L ic , height difference ΔH, number of configurations N r (N f ), configuration base moving distance ΔR (ΔC) and other structural parameters, so that there are heterogeneous distribution forms. The heterogeneous configuration includes the distribution form of the reinforcement ring or the pre-folded ring. The two aspects are different separately or simultaneously, so as to achieve the design goal of minimizing the initial peak load of the composite structure and subsequent load fluctuations while meeting the energy dissipation capacity.

[0078] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of protection of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that can be made by a person skilled in the art without departing from the principles of the present invention are also considered to be within the scope of protection of the present invention.

Claims

1. A multi-tube combined energy absorbing device based on a nested form, comprising an anti-climber (1), a plurality of nested energy absorbing tubes (2), a thin-walled shell (3) and a rear end plate (4), wherein the nested energy absorbing tubes (2) are fixed to the rear end plate (4); the rear end plate (4) is fixedly mounted on the front end of a vehicle, and is fixedly provided with a shell (3) on all four sides thereof, the shell (3) surrounds the nested energy absorbing tubes (2), and the anti-climber (1) is fixedly provided at the other end of the shell (3), characterized in that: The nested energy absorbing tube (2) comprises an outer tube (21) and an inner tube (22) both having thin walls, the cross sections of the inner and outer tubes both being square, the outer tube (21) bulging outwards at intervals along the tube height direction to form a plurality of square annular reinforcement rings (23), the inner tube (22) being pre-set with a plurality of folds (24), the folds (24) being arranged inwardly and outwardly at intervals; The parameters of the outer tube (21) include the initial height H of the outer tube (21) 外 , thickness t 外 , where the height h of the reinforcing ring (23) is r and thickness t r , N r The outer tube (21) is divided into N r+1 regions, each with a height of R ij , wherein i is the serial number of the outer tube (21) or the inner tube (22), j is the serial number of each area of ​​the outer tube (21) or the inner tube (22); the parameters of the inner tube (22) include the side length L of the inner tube (22) ic , initial height H 内 , thickness t 内 , where the fold offset distance ΔP, ΔP = 0.5C ij tanΔθ,N f The inner tube is divided into N parts by the folds f regions, each with a height of C ij , N r and N f Satisfy the following formula: L ic ≤L-2ΔP (3) Where δ sp is the theoretical half-wavelength of the wrinkles of the thin-walled square tube, I1(β0) and I3(β0) are the energy dissipation coefficients in the super-folding unit theory, L is the side length of the outer tube (21), and L ic is the side length of the inner tube (22); The thickness t of the reinforcing ring (23) r Satisfy the following requirements: PF r ≥F r =MCF (4) Where PF r is the limit load of the reinforcing ring (23), F r is the load applied by the outer tube (21) to the reinforcing ring (23), assuming that the maximum load value is MCF, MCF is the theoretical average load value of a traditional thin-walled square tube, σ0 is the flow stress of the material, t r is the thickness of the reinforcing ring, and E is the Young's modulus of the thin-walled material of the outer tube (21).

2. The nested multi-tube combined energy absorbing device according to claim 1, characterized in that: The offset distance ΔP of the fold (24) satisfies the following formula: PF1≤PF 1t (7) Where A is the cross-sectional area of ​​the structure, σ0 is the flow stress of the material, PF1 is the initial theoretical peak load of the inner pre-corrugated tube, and PF 1t is the initial theoretical peak load of a traditional thin-walled square tube with the same number of folds, tube height, and tube thickness, and t is the inner tube wall thickness.

3. The nested multi-tube combined energy absorbing device according to claim 2, characterized in that: The basic moving distance ΔR of the outer tube (21) is determined according to the number N of the outer tubes (21). i , height H 外 , the number N of the reinforcing rings (23) r To confirm:

4. The nested multi-tube combined energy absorbing device according to claim 2, characterized in that: The basic moving distance ΔC of the inner tube (22) is determined according to the number N of the inner tubes (22). i , height H 内 , the number N of the folds (24) f To confirm:

5. A vehicle comprising the nested multi-tube combined energy absorbing device according to any one of claims 1 to 4.

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