Energy absorption structure with directionally changed rigidity

Abstract

The invention relates to the technical field of railway vehicle buffering, in particular to an energy absorption structure with rigidity changing directionally. Comprising a plurality of rectangular units which are mutually connected in the horizontal direction and the vertical direction, free ends are arranged in the four directions of each rectangular unit, every two adjacent free ends of every two adjacent rectangular units are connected through a unit connecting plate, each rectangular unit comprises four metal plate frames, and the four metal plate frames are overlapped and nested to form the rectangular unit. And in the rigidity gradient increasing direction, the free end of the inner side of the metal plate frame of each layer of rectangular unit is gradually prolonged. Each rectangular unit internally comprises four same metal plate frames, the four metal plate frames are overlapped and nested, the free ends of the metal plate frames in the rectangular units are gradually prolonged in the rigidity gradient increasing direction, and an energy absorption structure with the rigidity changing directionally is formed. According to the energy absorption structure, rigidity directional change can be achieved through length change of the metal plate frame, and compared with an energy absorption structure without rigidity change, the energy absorption structure has better buffering capacity.

Description

Technical Field

[0001] The invention relates to the technical field of rail vehicle buffering, and in particular to an energy absorbing structure with directionally varying stiffness. Background Art

[0002] In rail train collision accidents, secondary collisions pose a serious threat to the life safety of passengers. Since rail trains are usually not equipped with personal safety protection equipment for passengers, passengers lack effective buffer protection in secondary collision accidents. In application scenarios such as collision protection, traditional energy-absorbing structures are usually one-piece and have uniform stiffness. However, this structure with uniform stiffness may not be able to fully utilize the deformation capacity of the material during the energy absorption process. Through local stiffness regulation, the energy-absorbing structure can more reasonably distribute deformation and energy absorption in different areas according to the actual situation of the collision, thereby improving the energy absorption efficiency. To achieve precise regulation of local stiffness, strict requirements are placed on the processing accuracy of the material. For the preparation of gradient stiffness structures, whether it is to change the material thickness or the internal microstructure to achieve stiffness changes, precision processing equipment and processes are required. Traditional processing methods are difficult to meet such high-precision requirements, and although advanced processing technologies (such as 3D printing) have certain advantages, they also face problems such as high cost and low efficiency. Summary of the invention

[0003] In order to overcome the technical problems in the prior art of complex processing methods, high processing costs and low efficiency of energy-absorbing structures with directional stiffness changes, the present invention provides an energy-absorbing structure with directional stiffness changes.

[0004] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: an energy-absorbing structure with directional stiffness variation, comprising a plurality of rectangular units interconnected in the horizontal direction and the vertical direction, each rectangular unit is provided with free ends in four directions, and two adjacent free ends of two adjacent rectangular units are connected by a unit connecting plate, the rectangular unit comprises four metal plate frames, the four metal plate frames are overlapped and nested to form a rectangular unit, and the free ends inside the metal plate frames of each layer of rectangular units are gradually extended along the direction of increasing stiffness gradient;

[0005] Preferably, the stiffness gradient increasing direction includes from top to bottom, from bottom to top, from left to right, from right to left, and from the middle to the upper and lower ends;

[0006] Preferably, the metal plate frame in the rectangular unit of the first layer includes a first connecting plate, a second connecting plate, and a third connecting plate, wherein the first connecting plate, the second connecting plate, and the third connecting plate are vertically connected end to end in sequence and bent inwards;

[0007] Preferably, the calculation expression of the length of the third connecting plate is:

[0008] L3=rL0

[0009] Wherein, L3 is the length of the third connecting plate; r is the nesting coefficient; L0 is the length of the unit connecting plate;

[0010] The calculation expression of the second connecting plate length is:

[0011] L2=L3+2d

[0012] Wherein, L2 is the length of the second connecting plate; L3 is the length of the third connecting plate; d is the nesting spacing between the metal plate frames; the calculation expression for the length of the first connecting plate is:

[0013] L1=L3 / 2+2d

[0014] Wherein, L1 is the length of the first connecting plate; L3 is the length of the third connecting plate; d is the nesting spacing between the metal plate frames;

[0015] Preferably, along the direction of increasing stiffness gradient, after the first layer, the length of the inner free ends of the metal plate frames of every two layers of rectangular units are extended the same, and after the first layer, the length of the inner free ends of the metal plate frames of every two layers of rectangular units is extended less than the length of the inner free ends of the metal plate frames of the upper two layers of rectangular units by the nesting spacing between one metal plate frame.

[0016] Preferably, the calculation expression for the length extended by the inner free end of the metal plate frame of the first two-layer rectangular unit is:

[0017] L 延 =L3 / 2-d

[0018] Among them, L 延 is the length extended by the free end of the inner side of the metal plate frame of the first two-layer rectangular unit, L3 is the length of the third connecting plate; and d is the nesting spacing between the metal plate frames.

[0019] Compared with the prior art, the beneficial effect of the present invention lies in that, by setting a plurality of rectangular units interconnected in the horizontal and vertical directions, and each rectangular unit contains four identical metal plate frames, the four metal plate frames are overlapped and nested, and the free ends of the metal plate frames in the rectangular units are gradually extended along the direction of increasing stiffness gradient, thereby forming an energy-absorbing structure with directional stiffness change. The energy-absorbing structure can achieve directional stiffness change only by changing the length of the metal plate frame. The energy-absorbing structure with stiffness change has better buffering capacity than the energy-absorbing structure without stiffness change, and can meet the application requirements of different environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the local structure of Example 1 in the specific implementation manner of the present invention.

[0021] Figure 2 It is a side view of the local structure of Example 1 in the specific implementation manner of the present invention.

[0022] Figure 3 It is a side view of a rectangular unit of Example 1 in a specific implementation manner of the present invention.

[0023] Figure 4 It is a schematic diagram of the connection structure of two metal plate frames in Example 1 of the specific implementation manner of the present invention.

[0024] Figure 5 It is a side view of the local structure of Example 2 in the specific implementation manner of the present invention.

[0025] Figure 6 It is a side view of the local structure of Example 3 in the specific implementation manner of the present invention.

[0026] Figure 7 It is a side view of the local structure of Example 4 in the specific implementation manner of the present invention.

[0027] Figure 8 It is a crush deformation diagram of a control example in a specific implementation manner of the present invention.

[0028] Fig. 9 It is a crush deformation diagram of Example 1 in a specific implementation manner of the present invention.

[0029] Fig.10 It is a crush deformation diagram of Example 2 in a specific implementation manner of the present invention.

[0030] Fig.11 It is a crush deformation diagram of Example 3 in a specific implementation manner of the present invention.

[0031] Fig.12 It is a crush deformation diagram of Example 4 in a specific implementation manner of the present invention.

[0032] Fig.13 1 is a crushing force-displacement curve of a control example in a specific embodiment of the present invention.

[0033] Fig.14 1 is a crushing force-displacement curve of a control example in a specific embodiment of the present invention.

[0034] Fig.15 1 is a crushing force-displacement curve of a control example in a specific embodiment of the present invention.

[0035] Fig.16 1 is a crushing force-displacement curve of a control example in a specific embodiment of the present invention.

[0036] Fig.17 1 is a crushing force-displacement curve of a control example in a specific embodiment of the present invention.

[0037] In the figure: 1, rectangular unit; 2, unit connecting plate; 3, metal plate frame; 301, first connecting plate; 302, second connecting plate; 303, third connecting plate; 4, free end. DETAILED DESCRIPTION

[0038] The specific implementation of an energy-absorbing structure with directional stiffness variation of the present invention is as follows:

[0039] Example 1: Figures 1 to 4 As shown, it includes a plurality of rectangular units 1 connected to each other in the horizontal direction and the vertical direction, each rectangular unit 1 is provided with free ends 4 in four directions, and the adjacent two free ends 4 of two adjacent rectangular units 1 are connected by a unit connecting plate 2. The rectangular unit 1 includes four metal plate frames 3, and the four metal plate frames 3 are overlapped and nested to form a rectangular unit 1. From top to bottom, the inner free ends of the metal plate frames 3 of each layer of rectangular units 1 are gradually extended inwards, and the layer with the smallest rigidity is the first layer. After the first layer, from top to bottom, that is, along the direction of increasing rigidity, the rectangular units of each two layers are connected. The lengths of the inner free ends of the metal plate frames 3 of the rectangular units 1 are the same, and after the first layer, the lengths of the inner free ends of the metal plate frames 3 of every two layers of rectangular units 1 are shorter than the lengths of the inner free ends of the metal plate frames 3 of the upper two layers of rectangular units 1 by the nesting spacing between the metal plate frames 3. The metal plate frames 3 in the rectangular units 1 of the first layer include a first connecting plate 301, a second connecting plate 302, and a third connecting plate 303. The first connecting plate 301, the second connecting plate 302, and the third connecting plate 303 are connected vertically end to end in sequence and bent inwards.

[0040] The calculation expression of the length of the third connecting plate 303 is:

[0041] L3=rL0

[0042] Wherein, L3 is the length of the third connecting plate 303; r is the nesting coefficient; L0 is the length of the unit connecting plate 2;

[0043] The length calculation expression of the second connecting plate 302 is:

[0044] L2=L3+2d

[0045] Wherein, L2 is the length of the second connecting plate 302; L3 is the length of the third connecting plate 303; d is the nesting spacing between the metal plate frames 3;

[0046] The length calculation expression of the first connecting plate 301 is:

[0047] L1=L3 / 2+2d

[0048] Wherein, L1 is the length of the first connecting plate 301; L3 is the length of the third connecting plate 303; d is the nesting distance between the metal plate frames 3;

[0049] The calculation expression for the length extended by the inner free end of the metal plate frame 3 of the first two-layer rectangular unit 1 after the first layer is:

[0050] L 延 =L3 / 2-d

[0051] Among them, L 延 is the length extended by the inner free end of the metal plate frame 3 of the first two-layer rectangular unit 1 , L3 is the length of the third connecting plate 303 ; and d is the nesting spacing between the metal plate frames 3 .

[0052] Example 2: Figure 5 As shown, it is basically the same as Example 1, except that in this embodiment, the stiffness gradient increases from bottom to top.

[0053] Example 3: Figure 6 As shown, it is basically the same as Example 1, except that in this embodiment, the direction of stiffness gradient increase is from the middle to the upper and lower ends.

[0054] Example 4: Figure 7 As shown, it is basically the same as Example 1, except that in this embodiment, the direction of stiffness gradient increase is from left to right.

[0055] Example 5: It is basically the same as Example 1, except that in this example, the stiffness gradient increases from right to left.

[0056] Control example: basically the same as Example 1, except that there is no change in stiffness in this control example, and the metal plate frame of the rectangular unit of each layer is exactly the same.

[0057] The control example and embodiments 1-4 were crushed, and the crushing deformation results were as follows: Figure 8-Figure 12 As shown, by comparison Figure 8-Figure 12It can be seen that the structures whose stiffness increases from top to bottom and from bottom to top present an inverted V-shaped deformation mode after crushing deformation, indicating that when subjected to crushing force, the uppermost layer of the structure is deformed first due to its lower stiffness. As the crushing force increases, the stiffness of the lower layer gradually increases, causing the deformation to gradually shrink inward, forming an inverted V-shaped deformation feature; when the stiffness gradient increases in the direction from the middle to the upper and lower ends, due to the lower stiffness of the middle structure, the result is that the middle structure is squeezed; when the stiffness gradient increases in the direction from right to left, the lower stiffness part is easy to discrete, and the deformation of the higher stiffness part is relatively stable; the structure without stiffness gradient increase presents a V-shaped deformation mode when subjected to crushing force, indicating that under the same crushing conditions, the upper layer is higher, and the first deformation is outward-turning. As the compression continues, the deformation gradually spreads to the lower layer, forming a V-shaped deformation structure. It can be seen that the design of the direction of stiffness gradient change affects the deformation mode of the structure.

[0058] The control example and embodiments 1-4 were crushed, and the crushing force displacement curves were as follows: Figure 13-Figure 17 As shown by Figure 13-Figure 17 It can be seen that the initial peak force of the energy-absorbing structure of Examples 1-4 is significantly lower than that of the energy-absorbing structure without stiffness gradient change, which can reduce the impact force during collision. From the image, it can be seen that the multi-stage platform force exhibits the characteristic of progressive energy absorption, which can better disperse and transition the load, and the crushing force is more stable.

[0059] The present invention is described by way of embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the protection scope of the present invention.

Claims

1. An energy-absorbing structure with directional stiffness variation, characterized in that: The invention comprises a plurality of rectangular units (1) interconnected in the horizontal direction and the vertical direction, each rectangular unit (1) being provided with free ends (4) in four directions, two adjacent free ends (4) of two adjacent rectangular units (1) being connected via a unit connection plate (2), the rectangular unit (1) comprising four metal plate frames (3), the four metal plate frames (3) being overlapped and nested to form the rectangular unit (1), and the inner free ends of the metal plate frames (3) of each layer of rectangular units (1) being gradually extended along the direction of increasing stiffness gradient.

2. The energy-absorbing structure with directionally varying stiffness according to claim 1, characterized in that: The directions of increasing the stiffness gradient include from top to bottom, from bottom to top, from left to right, from right to left, and from the middle to the upper and lower ends.

3. The energy-absorbing structure with directionally varying stiffness according to claim 2, characterized in that: The metal plate frame (3) in the rectangular unit (1) of the first layer comprises a first connecting plate (301), a second connecting plate (302), and a third connecting plate (303), wherein the first connecting plate (301), the second connecting plate (302), and the third connecting plate (303) are vertically connected end to end in sequence and bent inwards.

4. The energy-absorbing structure with directional stiffness variation according to claim 3, characterized in that: The calculation expression of the length of the third connecting plate (303) is: L3=rL0 Wherein, L3 is the length of the third connecting plate (303); r is the nesting coefficient; L0 is the length of the unit connecting plate (2); The calculation expression of the length of the second connecting plate (302) is: L2=L3+2d Wherein, L2 is the length of the second connecting plate (302); L3 is the length of the third connecting plate (303); d is the nesting distance between the metal plate frames (3); The length calculation expression of the first connecting plate (301) is: L1=L3 / 2+2d Wherein, L1 is the length of the first connecting plate (301); L3 is the length of the third connecting plate (303); and d is the nesting distance between the metal plate frames (3).

5. The energy-absorbing structure with directionally varying stiffness according to claim 2, characterized in that: Along the direction of increasing stiffness gradient, after the first layer, the lengths of the inner free ends of the metal plate frames (3) of every two layers of rectangular units (1) are extended to the same length, and after the first layer, the lengths of the inner free ends of the metal plate frames (3) of every two layers of rectangular units (1) are extended to a length that is shorter than the lengths of the inner free ends of the metal plate frames (3) of the upper two layers of rectangular units (1) by the nesting spacing between one metal plate frame (3).

6. The energy-absorbing structure with directionally varying stiffness according to claim 5, characterized in that: The calculation expression for the length extended by the inner free end of the metal plate frame (3) of the first two-layer rectangular unit (1) is: L 延 =L3 / 2-d Among them, L 延 is the length extended by the inner free end of the metal plate frame (3) of the first two-layer rectangular unit (1); L3 is the length of the third connecting plate (303); and d is the nesting spacing between the metal plate frames (3).

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