CN207737238U - A kind of gradient cutting buffering energy-absorbing structure - Google Patents

Abstract

The utility model belongs to the field of collision and energy absorption, and specifically discloses a buffer energy-absorbing structure with gradient grooves, which includes a plurality of thick-walled tubes and at least one thin-walled tube; the thick-walled tubes and the thin-walled tubes are arranged and connected at intervals along the axial direction As a whole, the central axis of the inner tube of the thick-walled tube coincides with the central axis of the inner tube of the thin-walled tube; each thin-walled tube is connected to a thick-walled tube at both ends, and the axial length and radial thickness of different thin-walled tubes are the same Along the axial gradient, the thin-walled tube with the longest axial length corresponds to the smallest radial thickness. The thick-walled tube and the thin-walled tube of the utility model are arranged at intervals along the axial direction and connected into a whole, and the axial lengths of different thin-walled tubes change along the axial gradient, so that the crush wrinkles occur sequentially from the longest section to the shortest section ; The radial thickness of different thin-walled tubes changes along the axial gradient, so that the crush wrinkles occur sequentially from the thinnest section to the thickest section; the radial thickness corresponding to the thin-walled tube with the longest axial length is the smallest, so that the crush wrinkles Where the pleats occur is more precisely controlled.

Description

A Gradient Groove Buffer Energy Absorbing Structure

technical field

The utility model belongs to the field of collision and energy absorption, in particular to a buffer energy-absorbing structure with gradient grooves.

Background technique

In practical projects such as aerospace, automobiles, rail vehicles, highway anti-collision facilities, nuclear power plants, etc., the energy absorption behavior of buffer energy-absorbing components plays a key role in the safety of impact-bearing structures. Due to the need for safety protection, the buffer energy-absorbing element needs to have the characteristics of good energy-absorbing effect, light weight, and long crushing stroke. Its structure must be as simple as possible and easy for industrial manufacturing and mass production.

At present, the traditional buffer energy-absorbing components are mainly thin-walled components, among which the axial crushing energy absorption of thin-walled tubular components is considered to be one of the most effective ways, and the most commonly used thin-walled tubes have circular cross-sectional shapes , square, hat-shaped, etc. Through experiments and theoretical verification, the energy absorption effect of circular section thin-walled pipes is obviously better than other types of thin-walled pipes under the same working conditions. However, the traditional round-section pipe is prone to non-axisymmetric instability during the crushing process. The advantage of the existing multi-stage crushing is that the part of the structure to be crushed can be selected according to the impact force.

However, most of the existing energy-absorbing structures, on the one hand, cannot effectively control the location of the collapse of the energy-absorbing tube, and there are a lot of uncertainties, which will cause unforeseen hidden dangers during the collision. On the other hand, as far as the current technical status is concerned, many structures that theoretically have better energy absorption effects and can realize multi-stage energy absorption functions are difficult to mass-produce and expensive.

Utility model content

Aiming at the problems existing in the prior art, the utility model provides a cushioning and energy-absorbing structure with gradient grooves; it can accurately control the occurrence position of crush wrinkles and is easy to manufacture.

The utility model is realized through the following technical solutions:

A gradient notch buffer energy-absorbing structure, characterized in that it includes several thick-walled tubes and at least one thin-walled tube; the thick-walled tubes and the thin-walled tubes are arranged at intervals along the axial direction and connected into a whole, and the inner part of the thick-walled tube The central axis of the tube coincides with the central axis of the inner tube of the thin-walled tube; each thin-walled tube is connected to a thick-walled tube at both ends, and the axial length and radial thickness of different thin-walled tubes change along the axial gradient, and the axial length The longest thin-walled tube corresponds to the smallest radial thickness.

The inner diameters of the thick-walled pipe and the thin-walled pipe are the same.

The cross-sections of the thick-walled tube and the thin-walled tube are both set to be circular, rectangular or elliptical.

The thickness of each of the thick-walled tubes is the same.

The axial length dimensions of the different thin-walled tubes are arranged in an arithmetic sequence or a geometric sequence along the axial direction.

The radial thickness dimensions of the different thin-walled tubes are arranged in an arithmetic sequence or a geometric sequence along the axial direction.

Compared with the prior art, the utility model has the following beneficial technical effects:

The thick-walled tubes and thin-walled tubes of the utility model are arranged at intervals along the axial direction and connected into a whole. The axial lengths of different thin-walled tubes change along the axial gradient, so that the crushed wrinkles are sequentially arranged from the longest section to the shortest section. occur; the radial thickness of different thin-walled tubes changes along the axial gradient, so that the crush wrinkles occur sequentially from the thinnest section to the thickest section; the thin-walled tube with the longest axial length corresponds to the smallest radial thickness, so that The location where crush folds occur is more precisely controlled.

Furthermore, the inner diameters of the thick-walled tube and the thin-walled tube of the present invention are the same, and the same inner diameter makes the stress of the energy-absorbing element more stable, and the position where the crush wrinkles occur can be more expected.

Further, the sections of the thick-walled pipe and the thin-walled pipe of the present invention are set to be circular, rectangular or elliptical. The expected site occurs.

Furthermore, the thickness of each thick-walled tube of the present invention is the same, and the thin-walled tubes of the same thickness make manufacturing more convenient and stress more stable.

Further, the axial lengths of different thin-walled tubes of the present invention are arranged in an arithmetic sequence or a geometric sequence along the axial direction, and the change in an arithmetic sequence or a geometric sequence makes the variation function change, which is convenient for preparation and crushes. Where wrinkles occur is easier to control.

Further, the radial thickness dimensions of different thin-walled tubes of the present invention are set in an arithmetic sequence or a geometric sequence along the axial direction, and the change in an arithmetic sequence or a geometric sequence makes the variation function change, which is convenient for preparation and crushes. Where wrinkles occur is easier to control.

Description of drawings

Fig. 1 is the side schematic diagram of the buffer energy-absorbing structure of gradient notch of the utility model;

Fig. 2 shows the non-axisymmetric crushing mode of the utility model, which is an ordinary circular section energy-absorbing tube with the same size as the energy-absorbing tube with gradient grooves in the embodiment of the utility model, which is axially compressed;

Fig. 3 is the discontinuous crushing mode caused by the axial compression of the energy-absorbing tube with gradient grooves of the same size as the energy-absorbing tube with gradient grooves in the embodiment of the present invention;

Fig. 4 is the continuous progressive crushing mode of the energy-absorbing tube with gradient grooves in the embodiment of the present invention under axial compression;

Fig. 5 is the force-displacement curves when the energy-absorbing tube with a circular cross section, the energy-absorbing tube with uniform grooves and the energy-absorbing tube with gradient grooves are axially crushed under the same size of the embodiment of the utility model.

In the figure: 1 is the thin-walled tube, 2 is the thick-walled tube, L is the tube length, D _O is the outer diameter of the thick-walled tube, D _I is the inner diameter of the thick-walled tube, W is the axial length of the thick-walled tube, w ₀ is The initial axial length of the thin-walled tube, w _i is the axial length of the i-th thin-walled tube, w _i+1 is the axial length of the i+1th thin-walled tube, d ₀ is the initial groove depth, d _i is the depth of the i-th groove, d _i+1 is the depth of the i+1-th groove.

Detailed ways

The utility model will be described in further detail below in conjunction with the accompanying drawings, which is an explanation of the utility model rather than a limitation.

As shown in Figures 1-5, the utility model gradient groove buffer energy-absorbing structure is characterized in that it includes several thick-walled tubes 2 and at least one thin-walled tube 1; the thick-walled tubes 2 and thin-walled tubes 1 are both axially Set at intervals and connected into a whole, the central axis of the inner tube of the thick-walled tube 2 coincides with the central axis of the inner tube of the thin-walled tube 1; both ends of each thin-walled tube 1 are connected with thick-walled tubes 2, different thin-walled tubes 1 Both the axial length and the radial thickness of the thin-walled tube 1 vary along the axial gradient, and the thin-walled tube 1 with the longest axial length has the smallest radial thickness.

The inner diameters of the thick-walled tube 2 and the thin-walled tube 1 are the same.

The cross-sections of the thick-walled tube 2 and the thin-walled tube 1 are both set to be circular, rectangular or elliptical.

The thickness of each of the thick-walled tubes 2 is the same.

The axial length dimensions of the different thin-walled tubes 1 are arranged in an arithmetic sequence or a geometric sequence along the axial direction.

The radial thickness dimensions of the different thin-walled tubes 1 are arranged in an arithmetic sequence or a geometric sequence along the axis direction.

A preparation method, characterized in that the energy-absorbing element is prepared by mechanical cold working.

The mechanical cold working is to use a lathe or a milling machine or a combination of both to carve grooves on the outer surface of the pipe to form a form in which the thick-walled pipe 2 and the thin-walled pipe 1 are distributed at intervals, and finally processed into the energy-absorbing element .

A preparation method, characterized in that 3D printing is used to prepare the energy-absorbing element, the energy-absorbing element of solid metal material is prepared by laser sintering, and the energy-absorbing element of solid non-metallic material is prepared by photocuring molding method.

The solid non-metallic material is PVC or resin.

The buffer energy-absorbing element with gradient width grooves is a gradient width groove energy-absorbing tube, and the gradient width groove energy-absorbing tube includes several alternately distributed grooves and thick walls in the axial direction, wherein the width of each thick wall part is the same, The wall thickness is the same, the depth of each notch is the same, the width gradually changes with a predetermined gradient along one end of the tube, and the thick wall part is always located at both ends of the energy-absorbing tube with gradient width notches.

Further, the cross-section of the energy-absorbing tube with gradient width grooves can be in any geometric shape such as a circle, a rectangle, and an ellipse.

Further, the energy-absorbing tube with gradient width grooves can be made of metal materials such as stainless steel and aluminum alloy, or non-metal materials such as PVC and resin.

Further, the manner in which the energy-absorbing tube with gradient width notches is impacted is in the axial direction and oblique impact at a certain angle to the axial direction, and both ends of the tube can withstand the impact force.

Further, the number of grooves of the gradient-width grooved energy-absorbing tube can be selected to be any value greater than 1.

Further, the expression method of the gradient may be an arithmetic sequence, a geometric sequence, or other functions or sequences that cause an uneven effect on the overall groove width, where is the th groove and is the th groove.

Further, the geometric parameters of the gradient-width grooved energy-absorbing tube in the wall thickness direction should satisfy the equation, where is the groove depth, is the wall thickness at the groove, and is the wall thickness of the thick-walled part.

Further, the preparation method of the gradient-width grooved energy-absorbing tube is mechanical cold working and 3D printing.

Further, the mechanical cold working preparation method of the gradient width grooved energy-absorbing tube can follow the following steps:

S1. Purchase seamless pipes according to the actual required cross-sectional shape and cross-sectional size;

S2, cutting the purchased seamless pipe according to the actual required pipe length;

S3, the cut seamless pipe is processed by machine tool (lathe, milling machine, etc.) according to the required gradient;

S4. Grinding the processed energy-absorbing tube with gradient width grooves to remove burrs.

Further, the 3D printing preparation method of the gradient-width grooved energy-absorbing tube can follow the following steps:

S1. Use CAD software such as Solidworks, UG, Pro/E, etc. to establish a three-dimensional data model of the energy-absorbing tube with gradient width grooves;

S2. Convert the three-dimensional data model of the energy-absorbing tube with gradient width grooves established in S1 into an stl format that can be recognized by a 3D printer;

S3. Input the stl format model generated by S2 into the 3D printer and use selective laser sintering (mainly for metal materials) or light curing molding method (mainly for non-metallic materials) to perform 3D printing;

S4. Take out the 3D-printed energy-absorbing tube with gradient width grooves from the machine, and brush off all residual powder.

In addition, in subsequent implementation examples, the selected geometric parameters and finite element simulation results are verified by test data, which can fully guarantee the accuracy of the results.

In the subsequent embodiment one of the present utility model, the energy absorbing effect and crushing mode of the cushioning energy-absorbing element described in the present utility model and the traditional circular tube and the uniform grooved circular tube in the quasi-static crushing process are compared. The novel energy-absorbing tube with gradient width grooves has better energy-absorbing effect and progressive crushing mode. The structure will first collapse at the groove with the largest width value, and gradually deform in the form of gradual collapse. By rationally designing its geometric parameters, the energy absorption efficiency can be further enhanced, and the lightweight design of the structure can be realized.

The product of the utility model has the advantages of simple structure and strong assembleability, and can be used as an independent energy-absorbing buffer element. Under a specific application, multiple energy-absorbing energy-absorbing elements notched with gradient widths can cooperate to work together.

The preparation process of the product of the utility model is simple, and can be directly obtained by cold processing the seamless pipe sold on the market, without re-opening the mold for manufacture. Simultaneously, the alternative material of the product of the utility model is extensive, can adopt metal materials such as stainless steel, aluminum alloy, also can adopt non-metallic materials such as PVC, resin.

Embodiment one

In this embodiment, the gradient-grooved buffer energy-absorbing structure is a gradient-grooved round-section energy-absorbing tube (referred to as a gradient-grooved tube). The number of engraved grooves in this embodiment is 5, wherein the depths of the three engraved grooves at the bottom are the same, the depths of the two engraved grooves at the top are the same, and the depth d of the engraved grooves changes according to the form of arithmetic sequence, and the depth coefficient That is, the thicknesses of the fourth and fifth thin-walled tubes are smaller than those of the first, second and third thin-walled tubes. At the same time, the width w of the groove changes in the form of an arithmetic sequence, and the width coefficient γ=w _i+1 -w _i =3.36mm; that is, the first, second, third, fourth and fifth thin-walled tubes The axial length of the tube increases in turn, so that the thin-walled tube with the shortest axial length has the largest radial thickness, and the thin-walled tube with the longest axial length has the smallest radial thickness.

In order to verify the advantages of the gradient grooved tube, it is compared with the ordinary circular cross-section energy-absorbing tube and the uniform grooved tube of the same size and material, and the energy absorption of the three types of energy-absorbing tubes under the condition of axial quasi-static crushing is analyzed Effect, the specific dimensions selected in this embodiment are shown in Table 1, and the units of the geometric parameters in the table are all (mm).

Table 1

To verify the superiority of the gradient grooved pipe described in the utility model, it needs to carry out finite element simulation test by Abaqus/Explicit software, wherein, the finite element simulation parameters are set as follows:

Ordinary round pipes, uniform grooved pipes, and gradient grooved pipes are all made of mild steel, with a density of 7.8g/cm ³ , an elastic modulus of 210GPa, a Poisson’s ratio of 0.3, and a material yield strength of 372MPa. The material ultimate strength is 526MP. The bottom of the tube is placed on a fixed rigid plate, and the other rigid plate is loaded at a constant speed of 1mm/min from the direction of the collision. The purpose is to study the energy absorption characteristics of three types of energy-absorbing tubes under low-speed impact by means of quasi-static tests and crush mode. In the calculation, the three types of pipes and the rigid plate all use the general contact based on the penalty function method, and the friction factor is 0.15. In order to ensure the calculation efficiency of Abaqus/Explicit under quasi-static collapse, the combination of the lowest order mode of the system and the smooth amplitude curve is used to improve the calculation speed.

Figure 2 shows the crush mode of an ordinary energy-absorbing tube with a circular cross-section. It can be visually observed that the circular tube has undergone non-axisymmetric instability. Due to the strong randomness of the non-axisymmetric crush mode of the circular tube and the low energy absorption efficiency, there will be greater uncertainty when it is used in energy-absorbing elements with relatively precise structures such as vehicles or crash pads. There is also the possibility of a more unstable Euler buckling mode as the tube length increases further. Therefore, in the design of this type of energy-absorbing element, the non-axisymmetric crush mode of the circular tube should be avoided as much as possible.

Figure 3 shows the crush mode of the uniformly grooved energy-absorbing tube. It can be visually observed that the uniformly grooved tube is more stable than the ordinary round tube during the crushing process, and all thin-walled parts have axisymmetric crush mode. However, it is difficult to control the crushed part of the energy-absorbing tube with uniform grooves. It can be seen from Figure 3 that the first crushed part is located at the second groove at the loading end, and the second crushing occurs at the first groove at the loading end. At the notch, followed by crushing the second notch at the fixed end, etc. Therefore, while ensuring stability, the energy-absorbing structure still does not solve the randomness of the location where wrinkles are generated during crushing.

Figure 4 shows the crushing mode of the energy-absorbing tube with gradient grooves. It can be observed intuitively that the gradient grooved tube has the advantages of stability of the uniform grooved tube, and can also stably form a deformation mode of axial progressive crushing. It can be seen from Figure 4 that the first crushed part is located at the groove with a depth of 2.5mm, and the three grooves with a depth of 2mm are not crushed until the thin-walled parts at the two grooves are completely crushed. the thin-walled part. It can be seen from Figure 4 that the thin-walled tube with the longest axial length and the smallest radial thickness is crushed first, and the thin-walled tube with the shortest axial length and the largest radial thickness is crushed last.

Figure 5 shows the force-displacement curves of ordinary circular section energy-absorbing tubes, uniformly grooved energy-absorbing tubes, and gradient grooved energy-absorbing tubes under the same size when they are axially crushed. After comparison, it can be seen that the force-displacement curves of gradient grooved energy-absorbing tubes are different due to the different groove depths. There are two obvious platforms, the first platform is at the same level as the curve of the uniformly grooved energy-absorbing tube and the energy absorption capacity is greater than that of the uniformly grooved tube, the force value of the second platform has a significant increase, and the overall gradient groove The energy-absorbing tube has good multi-stage energy-absorbing characteristics.

In order to compare the energy absorption capacity of the gradient grooved tube and the uniform grooved tube, Table 2 summarizes the data presented by the force-displacement curve in Fig. 5, the total energy absorption of the gradient grooved tube is 22.33% more than that of the uniform grooved tube, The crushing distance of the grooved tube is 0.22% less than that of the uniform grooved tube, and the average crushing force of the gradient grooved tube is 22.58% higher than that of the uniform grooved tube, which fully demonstrates the superiority of the gradient grooved tube in the process of energy absorption.

Table 2

The cold processing preparation method of the energy-absorbing tube with gradient grooves in this embodiment can follow the following steps:

S1, buy some commercially available mild steel seamless round pipes with a wall thickness of 4mm for spare use;

S2, according to the size described in Table 1, the seamless round pipe is cut according to the specified pipe length L=144mm;

S3. Pass the cut seamless circular tube through the lathe according to the groove characteristics described in Table 1 (N=5, w=10.08mm, d ₀ =2.5mm, η=d _i+1 - _{d i} =0.5mm , γ=w _i+1 -w _i =3.36mm) to obtain a gradient grooved tube.

S4. Grinding the processed energy-absorbing tube with gradient grooves to remove burrs.

To sum up, compared with the uniform grooved tube of the same size, the gradient grooved tube can not only greatly improve the energy absorption efficiency, but also provide a more stable and controllable multi-level deformation mode. In addition, the gradient grooved tube described in this embodiment has the advantages of simple processing and low cost.

The outer tube of the thin-walled tube 1 and the outer tube of the thick-walled tube 2 connected at both ends form a slotted space along the axial direction; the axial length and radial depth of different slotted spaces vary in gradient along the axial direction.

The above content is only to illustrate the technical ideas of the present utility model, and cannot limit the scope of protection of the present utility model. Any changes made on the basis of technical solutions according to the technical ideas proposed by the present utility model all fall into the scope of the utility model. within the scope of protection of the claims.

Claims (6)

1. A gradient grooved buffer energy-absorbing structure, characterized in that it comprises several thick-walled tubes (2) and at least one thin-walled tube (1); the thick-walled tubes (2) and the thin-walled tubes (1) are all along the axis The central axis of the inner tube of the thick-walled tube (2) coincides with the central axis of the inner tube of the thin-walled tube (1); the two ends of each thin-walled tube (1) are connected with thick-walled tubes (2), the axial length and radial thickness of different thin-walled tubes (1) vary along the axial gradient, and the thin-walled tube (1) with the longest axial length has the smallest radial thickness. 2. The energy-absorbing structure with gradient grooves according to claim 1, characterized in that the inner diameters of the thick-walled pipe (2) and the thin-walled pipe (1) are the same. 3. The energy-absorbing structure with gradient grooves according to claim 1, characterized in that, the cross-sections of the thick-walled pipe (2) and the thin-walled pipe (1) are both set in a circular, rectangular or elliptical shape. 4. The energy-absorbing structure with gradient grooves according to claim 1, characterized in that, each of the thick-walled tubes (2) has the same thickness. 5. The energy-absorbing structure with gradient grooves according to claim 1, characterized in that the axial length dimensions of the different thin-walled tubes (1) are arranged in an arithmetic progression or a geometric progression along the axial direction. 6. The energy-absorbing structure with gradient grooves according to claim 1, characterized in that, the radial thickness dimensions of the different thin-walled tubes (1) are arranged in an arithmetic sequence or a geometric sequence along the axis direction.