Preparation method of automobile energy absorption box filled with bionic double-chiral structure

Abstract

The invention discloses a preparation method of an automobile energy absorption box filled with a bionic double-chiral structure, and relates to the technical field of automobile collision safety. The scheme that a traditional honeycomb structure is matched with a chiral structure is further optimized, bionic optimization design of the double-chiral structure is achieved and applied to the field of automobile energy absorption boxes, and three bionic optimization structures combining the double-chiral characteristics are established. And experiments prove that through the synergistic effect of the honeycombs and the double chiral units, the peak force of the energy absorption box in the initial collision stage can be effectively reduced, and meanwhile, the specific energy absorption is remarkably improved. Under the impact load effect, the structure shows a more stable and controllable deformation mode, the instability phenomenon of a traditional energy absorption structure is avoided, and an optimized solution is provided for automobile collision safety protection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobile crash safety, and particularly relates to a preparation method of a bionic dual-chiral structure filled automobile energy absorption box. BACKGROUND

[0002] The specific strength and specific energy absorption of the materials such as low-carbon steel or aluminum alloy used in the traditional energy absorption box are limited, and it is difficult to meet the increasingly improved crash safety requirements under the premise of lightweight; and the tensile strength and yield strength of TC4 titanium alloy are much higher than those of typical automobile aluminum alloys (such as 6061 or 7075). More importantly, its specific strength (ratio of strength to density) is particularly outstanding. This means that the TC4 energy absorption box can be designed to be lighter to contribute to further weight reduction of the whole vehicle while achieving the same energy absorption effect. At the same time, the TC4 material can absorb more energy during plastic deformation, laying a material foundation for its excellent crashworthiness.

[0003] The traditional energy absorption box mostly adopts a honeycomb or porous structure design, and such a structure has a high initial peak force when impacted, which is easy to cause stress concentration and thus early failure of the structure. At the same time, the energy absorption value of the traditional design is low, and the energy absorption efficiency is limited, which cannot fully meet the high requirements of modern automobiles on crash safety. In addition, the traditional structure often lacks stable progressive collapse behavior during deformation, resulting in uneven energy absorption process and further reducing its comprehensive performance.

[0004] The chiral structure as a new type of structural design form has shown remarkable advantages in the field of energy absorption boxes. First, the chiral structure has a unique geometric configuration and can realize uniform energy dissipation through rotation and deformation when impacted, thereby effectively reducing the initial peak force and avoiding stress concentration. Second, the chiral structure has excellent controllable deformation capability and can optimize the energy absorption path by adjusting the structural parameters to significantly improve the energy absorption value and energy absorption efficiency. In addition, the chiral structure also has good recoverability and reusability, providing a new research direction and application prospect for the lightweight and high-performance of automobile energy absorption boxes. SUMMARY

[0005] In view of the above problems existing in the prior art, the purpose of the present application is to provide a preparation method of a bionic dual-chiral structure filled automobile energy absorption box.

[0006] The technical scheme adopted by the present application is as follows: A preparation method of a bionic dual-chiral structure filled automobile energy absorption box, comprising the following steps: Step one, optimizing single chiral features and multiple chiral features on the basis of traditional honeycomb structure by combining chiral features; Step two, based on three-dimensional modeling software to establish the model of four kinds of biomimetic chiral structure, four kinds of biomimetic chiral structure include single chiral structure, double chiral structure A type, double chiral structure B type and double chiral structure C type; Step three, the four kinds of biomimetic chiral structure model designed in step two is imported into three-dimensional printing software, and the preparation of TC4 material biomimetic chiral structure is completed based on selective laser melting technology; Step four, the prepared biomimetic chiral structure is filled into the inside of the automobile energy absorption box.

[0007] Further, the design method of the single chiral structure is as follows: Based on the front reference plane, draw a regular hexagon contour and stretch, the stretching direction is defined as Z axis, form a regular hexagonal sheet structure, then draw a regular hexagon with rounded corners on the regular hexagonal sheet structure, the regular hexagon with rounded corners is the same as the regular hexagon with the center point and the six sides parallel to each other, the size of the regular hexagon with rounded corners is smaller than the regular hexagonal sheet structure, cut off the regular hexagonal structure part with rounded corners on the regular hexagonal sheet structure, form a regular hexagonal sheet structure with a regular hexagonal hole with rounded corners in the middle; Based on the front reference plane, the six top corners of the regular hexagonal sheet structure are named, starting from the top corner on the left side, the top corners are defined as A, B, C, D, E and F in clockwise direction, then the regular hexagonal sheet structure is arrayed along Z axis direction three times; After arraying, the regular hexagonal sheets are defined as first sheet, second sheet, third sheet and fourth sheet from top to bottom in sequence; Based on the E point of the first sheet and the D point of the second sheet, a straight line is drawn, the straight line is used as a guide line, then a circular contour is drawn and scanned on the guide line using the circular contour, to establish a first rib entity; Based on the top reference plane, the first rib entity is circumferentially arrayed six times with the center point of the regular hexagonal sheet structure, so that each vertex of the bottom surface of the first sheet and the top surface of the second sheet is connected with the first rib entity; Based on the D point of the second sheet and the E point of the third sheet, a straight line is drawn, the straight line is used as a guide line, then a circular contour is drawn and scanned on the guide line using the circular contour, to establish a second rib entity; Based on the front reference plane, the second rib entity is circumferentially arrayed six times with the center point of the regular hexagonal sheet structure, so that each vertex of the bottom surface of the second sheet and the top surface of the third sheet is connected with the second rib entity; The rib entity arranged between the third sheet and the fourth sheet is the same as the first rib entity, and the four sheets and three groups of rib entities jointly constitute a single chiral structure monomer; The single-chiral structure monomer is arrayed along the straight lines AE, CE and FD once, and then the single-chiral structure monomer is arrayed along the straight lines EA, EC and DF once, and finally the single-chiral structure is obtained.

[0008] Further, the design method of the double-chiral structure A type is as follows: Two circles with diameters of D1 and D2 are drawn, and D1 is greater than 2D2. A spiral line is drawn based on the circle with the diameter of D1, the pitch of the spiral line is c1, the number of turns is 1, and the initial angle is set to 180°. The length of the spiral line in the vertical direction is the same as the length of the guide line between the first thin plate and the second thin plate. A circle with the diameter of D2 is used to scan the spiral line, and the A type rib structure is established. Then the A type rib structure is centrally symmetric based on the center of the circle with the diameter of D1, and the A type double rib structure is obtained. The A type double rib structure is replaced by the first rib entity and the second rib entity to obtain the double-chiral structure A type monomer. The double-chiral structure A type monomer is arrayed along the straight lines AE, CE and FD once, and then the double-chiral structure A type monomer is arrayed along the straight lines EA, EC and DF once, and finally the double-chiral structure A type is obtained.

[0009] Further, the design method of the double-chiral structure B type is as follows: Two circles with diameters of D1 and D2 are drawn based on the upper reference plane, and D1 is greater than 2D2. A spiral line is drawn based on the circle with the diameter of D1, the pitch of the spiral line is c2, the number of turns is 2, and the initial angle is 180°. The length of the spiral line in the vertical direction is the same as the length of the guide line between the first thin plate and the second thin plate. The spiral line is projected on the front reference plane to obtain a scanning curve. At this time, a circle with the diameter of D2 is used to scan the scanning curve, and the B type rib structure is established. A vertical line is drawn through the center of the circle with the diameter of D1 based on the front reference plane, and the vertical line is projected on the plane where the scanning curve is located to obtain a projection line. The plane where the vertical line and the projection line are located is defined as the reference plane. The B type rib structure is mirrored based on the reference plane to obtain the B type double rib structure. The B type double rib structure is replaced by the first rib entity and the second rib entity to obtain the double-chiral structure B type monomer. The double-chiral structure B type monomer is arrayed along the straight lines AE, CE and FD once, and then the double-chiral structure B type monomer is arrayed along the straight lines EA, EC and DF once, and finally the double-chiral structure B type is obtained.

[0010] Further, the design method of the double-chiral structure C type is as follows: Based on the upper reference surface, two circles are drawn, with diameters D1 and D2 respectively, and D1 is greater than 2D2, based on the circle with diameter D1, the pitch of the spiral line is c3, the number of turns is 1.5, and the starting angle is 180°, wherein the length of the spiral line in the vertical direction is the same as the length of the guide line between the first thin plate and the second thin plate, and the projection of the spiral line on the front reference surface is obtained to obtain the scanning curve, at this time, the scanning curve is scanned on the scanning curve using a circle with a diameter of D2, and a C-shaped rib structure is established; Based on the front reference surface, a vertical line passing through the center of the circle with diameter D1 is drawn, the projection line of the vertical line to the plane where the scanning curve is located is drawn, and the plane where the vertical line and the projection line are located is defined as the reference plane, and the C-shaped rib structure is mirrored based on the reference plane to obtain a C-shaped double rib structure; The C-shaped double rib structure is replaced by the first rib entity and the second rib entity to obtain a chiral structure C monomer; The chiral structure C monomer is arrayed along the straight lines AE, CE and FD once, and then the chiral structure C monomer is arrayed along the straight lines EA, EC and DF once, and finally the chiral structure C is obtained.

[0011] Further, the preparation method in step three is selective laser melting technology, the particle size range of the selected TC4 powder is 15-53 microns, the laser power used is 180w, the scanning speed is 800mm / s, the layer thickness is 20μm, and the interval is 60μm.

[0012] Compared with the prior art, the beneficial effects of the present application are: The chiral structure prepared by the present application effectively reduces the initial peak force, and compared with the traditional energy-absorbing box honeycomb thin-walled structure, the safety of the driver is more effectively guaranteed.

[0013] The deformation mode of the bichiral biomimetic structure designed by the present application is more stable than that of the single chiral biomimetic structure and the traditional honeycomb structure, and stress concentration is not easy to occur, which is more suitable for automobile protection working conditions, and the energy absorption and specific energy absorption are higher than those of the traditional honeycomb structure, effectively improving the impact resistance in the field of automobile protection. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic diagram of the optimization of the traditional honeycomb structure and four kinds of biomimetic chiral structures; Figure 2 is a modeling flowchart of the traditional honeycomb structure and the single chiral structure; Figure 3 is a modeling flowchart of the bichiral structure A, the bichiral structure B and the bichiral structure C; Figure 4 is the actual compression stress-strain curve of the five types of structures; Figure 5 is a magnified view of the initial peak stress part of the actual compressive stress-strain curve of the five types of structures; Figure 6 is the actual energy absorption curve of the five types of structures; Figure 7 is the actual specific energy absorption curve of the five types of structures; Figure 8 is the deformation mode and stress cloud map of the traditional honeycomb structure and the single chirality structure; Figure 9 is the deformation mode and stress cloud map of the double chirality structure A and the double chirality structure B; Figure 10 is the deformation mode and stress cloud map of the double chirality structure C; Figure 11 is the working effect comparison chart of the energy absorption box before and after improvement of the present application.

[0015] In the figure: 11, traditional honeycomb structure monomer; 1, traditional honeycomb structure; 21, single chirality structure monomer; 2, single chirality structure; 31, double chirality structure A monomer; 3, double chirality structure A; 41, double chirality structure B monomer; 4, double chirality structure B; 51, double chirality structure C monomer; 5, double chirality structure C. DETAILED DESCRIPTION

[0016] The present application will be further described below in conjunction with specific embodiments.

[0017] Chirality refers to the property of an object that cannot be completely superimposed with its mirror image. The present scheme is designed based on the chirality characteristics of vine plants such as morning glory and hops in nature, as shown in Figure 1 Vine plants (such as morning glory, hops, etc.) exhibit typical chiral growth behavior in nature: the stem ends will spontaneously form a regular spiral winding structure along the support (such as a tree trunk, a fence) during extension. This macroscopic chiral morphology not only helps the plant to firmly climb, but also reflects unique advantages in mechanical properties. The spiral structure can effectively dissipate energy by its own elastic rotational deformation when bearing external force (such as wind), thereby buffering the instantaneous load and avoiding the risk of rupture caused by direct pulling, realizing the unity of flexibility and structural stability.

[0018] The specific steps for preparing the biomimetic chirality structure in the present scheme are as follows: Step one: based on the chirality characteristics, the single chirality feature optimization and the multi-chirality feature optimization are carried out on the basis of the traditional honeycomb structure 1.

[0019] Step two: based on the three-dimensional modeling software Solidworks, the models of the four kinds of biomimetic chirality structures are established.

[0020] Step three: The four kinds of chiral structure models designed in step two were imported into Magics software, and TC4 chiral structures were prepared based on the selected laser melting technology, which were named as single chiral structure 2 (Chiral structure, abbreviated as CS), doubly chiral structure A type 3 (Doubly chiral structure-A, abbreviated as DCSA), doubly chiral structure B type 4 (Doubly chiral structure-B, abbreviated as DCSB), and doubly chiral structure C type 5 (Doubly chiral structure-C, abbreviated as DCSC).

[0021] Step four: The prepared chiral structure was filled into the inside of the automobile energy absorption box, and the loading surface of the chiral structure was oriented in the same direction as the expected impact direction of the automobile energy absorption box.

[0022] In order to conduct a control experiment, the traditional honeycomb structure 1 also underwent the same preparation process as steps three and four in this embodiment, and the control group was named as traditional honeycomb structure 1 (Traditional honeycomb structure, abbreviated as THS).

[0023] Referring to Figure 2 The modeling process of the traditional honeycomb structure 1 and the single chiral structure 2 is as follows: The single chiral structure 2 and the traditional honeycomb structure 1 include a plurality of thin plate structures and a plurality of straight rods, the straight rods are located between the thin plate structures and are used to connect the thin plate structures, the difference between the single chiral structure 2 and the traditional honeycomb structure 1 lies in whether the arrangement direction of the straight rods is consistent. First, a regular hexagon contour is drawn based on the center point of the front reference surface and stretched to generate a regular hexagon thin plate structure, the stretching direction is defined as the Z axis, the regular hexagon side length in this embodiment is set to 3.28 mm, and the wall thickness is set to 0.61 mm, then a regular hexagon with rounded corners is drawn on the regular hexagon thin plate structure, the regular hexagon with rounded corners has the same center point as the regular hexagon and the six sides are parallel to each other, the size of the regular hexagon with rounded corners is smaller than that of the regular hexagon thin plate structure, and the regular hexagon with rounded corners is cut off on the regular hexagon thin plate structure to form a regular hexagon thin plate structure with a regular hexagon with rounded corners in the middle.

[0024] The regular hexagon thin plate structure is arrayed along the Z axis direction three times with an array distance of 3.8 m, ensuring that there are three layers of structures after filling the straight rods later; the six top corners of the regular hexagon thin plate structure are named based on the upper top corner from the left side, and the top corners are defined as A, B, C, D, E, and F in clockwise direction; After the array is completed, the four regular hexagon thin plates are defined as the first thin plate, the second thin plate, the third thin plate, and the fourth thin plate from top to bottom; Based on the first sheet E point and the second layer sheet D point to make a straight line, with the straight line as the guide line, then draw a circular profile and use the circular profile to scan on the guide line, establish the first rib entity; Based on the upper view reference surface, the center point of the regular hexagonal sheet structure is circularly arrayed six times, realizing that each vertex of the top surface of the second sheet is connected with the first rib entity; Based on the second sheet D point and the third sheet E point to make a straight line, with the straight line as the guide line, then draw a circular profile and use the circular profile to scan on the guide line, establish the second rib entity; Based on the upper view reference surface, the center point of the regular hexagonal sheet structure is circularly arrayed six times, realizing that each vertex of the top surface of the third sheet is connected with the second rib entity; The rib entity between the third sheet and the fourth sheet is the same as the first rib entity, and the four sheets and the three groups of rib entities jointly constitute a single chirality structure monomer 21; The single chirality structure monomer 21 is arrayed along the straight lines AE, CE and FD once, forming the first array source as shown in Figure 2 The circle marked is the single chirality structure monomer 21 which is initially arrayed, and then the single chirality structure monomer 21 is arrayed along EA, EC and DF once, and the array size is 5.68mm, and finally the single chirality structure 2 is obtained, and the specific shape is shown in the second array source as shown in Figure 2 .

[0025] The construction method of the traditional honeycomb structure 1 is completely the same as the overall construction process of the single chirality structure 2, and the difference lies in that the rib entities in the traditional honeycomb structure monomer 11 are not divided into first rib entities and second rib entities, and all the rib entities in the traditional honeycomb structure monomer 11 are second rib entities in the single chirality structure monomer 21, that is, the ribs in the traditional honeycomb structure monomer 11 are in the same direction.

[0026] The array is performed using the constructed traditional honeycomb structure monomer 11, and the array method is completely the same as that of the single chirality structure monomer 21, and finally the traditional honeycomb structure 1 is obtained.

[0027] The modeling processes of the double chirality structure A type 3, the double chirality structure B type 4 and the double chirality structure C type 5 are referred to as shown in Figure 3 The difference between the three double chirality structures and the single chirality structure 2 lies in that the rib in the shape of a straight rod is replaced by a rib structure designed to simulate the chirality structure, so only such differences are described here, and the remaining construction steps are consistent with the single chirality structure 2, so they will not be described in detail.

[0028] The design method of the double chirality structure A type 3 is as follows: Draw two circles with diameters D1 and D2, respectively, and D1 is greater than 2D2, the circle with diameter D2 is inscribed in the circle with diameter D1, draw a helix based on the circle with diameter D1, the helix has a pitch of c1 and 1 turn, and the starting angle is set to 180°, wherein the length of the helix in the vertical direction is the same as the length of the guide line between the first thin plate and the second thin plate, scan the helix using a circle with diameter D2 to establish an A-type rib structure, and then center-symmetrize the A-type rib structure based on the center of the circle with diameter D1 to obtain an A-type double-rib structure; Replace the first rib entity and the second rib entity with the A-type double-rib structure to obtain a chiral structure A-type monomer 31; Array the chiral structure A-type monomer 31 along the straight lines AE, CE, and FD once, and then array the chiral structure A-type monomer 31 along the straight lines EA, EC, and DF once to finally obtain a chiral structure A-type 3.

[0029] The design method of the chiral structure B-type 4 is as follows: Draw two circles with diameters D1 and D2, respectively, and D1 is greater than 2D2 based on the top reference surface, draw a helix based on the circle with diameter D1, the helix has a pitch of c2 and 2 turns, and the starting angle is 180°, wherein the length of the helix in the vertical direction is the same as the length of the guide line between the first thin plate and the second thin plate, project the helix on the front reference surface to obtain a scanning curve, and then scan the scanning curve using a circle with diameter D2 to establish a B-type rib structure; Based on the front reference surface, draw a vertical line passing through the center of the circle with diameter D1, project the vertical line to the plane where the scanning curve is located to obtain a projection line, define the plane where the vertical line and the projection line are located as a reference plane, and mirror the B-type rib structure based on the reference plane to obtain a B-type double-rib structure; Replace the first rib entity and the second rib entity with the B-type double-rib structure to obtain a chiral structure B-type monomer 41; Array the chiral structure B-type monomer 41 along the straight lines AE, CE, and FD once, and then array the chiral structure B-type monomer 41 along the straight lines EA, EC, and DF once to finally obtain a chiral structure B-type 4.

[0030] The design method of the chiral structure C-type 5 is as follows: Two circles are drawn based on the upper reference plane, with diameters D1 and D2, and D1 is greater than 2D2. Based on the circle with diameter D1, the helix has a pitch of c3, 1.5 turns, and a starting angle of 180°. The length of the helix in the vertical direction is the same as the length of the guide line between the first thin plate and the second thin plate. Projecting the helix on the front reference plane obtains a scan curve. At this time, a circle with diameter D2 is used to scan the scan curve, and a C-shaped rib structure is established. Based on the front reference plane, a vertical line is drawn through the center of the circle with diameter D1. Project the vertical line onto the plane where the scan curve is located to obtain a projection line. Define the plane where the vertical line and the projection line are located as the reference plane. Mirror the C-shaped rib structure based on the reference plane to obtain a C-shaped double rib structure. Replace the first rib entity and the second rib entity with the C-shaped double rib structure to obtain a chiral structure C monomer 51. Array the chiral structure C monomer 51 along the straight lines AE, CE, and FD once, and then array the chiral structure C monomer 51 along the straight lines EA, EC, and DF once. Finally, obtain a chiral structure C 5.

[0031] After the model is established, import the model into the Magics software, and complete the preparation of the TC4 biomimetic structure based on the selective laser melting technology. In this embodiment, the particle size of the TC4 powder used is 15-53 microns, the laser power used is 180w, the scanning speed is 800mm / s, the layer thickness is 20μm, and the interval is 60μm. The volume ratio of the five structures produced is consistent, all being 360.760~361.095mm 3 , and the outline size is also consistent at 17.03x16.39x12mm, so as to facilitate subsequent performance testing.

[0032] After preparation, the obtained model is subjected to static compression test. In this embodiment, the test equipment selected is a 100KN KQL type universal testing machine, and the compression rate is 1mm / min, so as to meet the interval of quasi-static compression experiment. Each experiment is performed three times to avoid experimental error.

[0033] After the static compression test is completed, the performance of several structures is tested based on the finite element model. The finite element simulation is processed by Hyperworks combined with Abaqus. In view of the precision of the grid size, the Hypermesh module in Hyperworks is used to draw the grid. Then, the inp format file is exported and imported into Abaqus in the state of the processor selected as Abaqus for the next compression simulation.

[0034] The parameters of the Abaqus model are set as follows: the material behavior is added with density, elasticity, plasticity and flexible damage (including damage evolution). The density is set to 4.425E-09 (unified unit system), the elastic modulus in the elastic module is set to 42000, and the Poisson's ratio is set to 0.33. In the plastic module, 37 stress-strain points in the yield stage are selected. In the flexible damage module, the fracture strain is set to 0.4, and in the damage evolution module, the fracture energy is set to 60.

[0035] The final performance test results are shown in Figures 4-10 , wherein Figures 4-7 are various mechanical curves obtained during the static compression test, including the actual stress-strain curve, the actual energy absorption curve and the actual specific energy absorption curve, Figure 8 , Figure 9 , Figure 10 are the structural deformation modes obtained during the static compression test of the five structures and the stress contour in the finite element simulation.

[0036] Referring to the mechanical curve data in Figure 4 and Figure 5 , the single-handed structure 2 and the three double-handed structures can effectively reduce the initial peak stress. The stress of the single-handed structure 2 is 27.29 MPa, which is reduced by 14.10% compared with the stress 31.77 Mpa of the traditional honeycomb structure 1. The initial peak stresses of the same double-handed structure A type 3, double-handed structure B type 4 and double-handed structure C type 5 are 30.74 Mpa, 14.07 Mpa and 24.65 Mpa, respectively, which are reduced by 3.20%, 55.71% and 22.41% compared with the traditional honeycomb structure 1. It is shown that the integration of the chiral feature can effectively relieve the initial peak pressure, so that the safety of the driver can be greatly improved when encountering a collision.

[0037] Referring to Figure 6 and Figure 7 , it can be seen that the energy absorption and specific energy absorption of the double-handed structure A type 3, double-handed structure B type 4 and double-handed structure C type 5 are better than those of the traditional honeycomb structure 1 and the single-handed structure 2. This shows that further optimization of the chiral feature of the local rib can greatly increase the energy absorption capacity of the structure. The energy absorption value and specific energy absorption value of the double-handed structure A type 3 are the highest, which shows that it is the best energy absorption structure.

[0038] Referring to Figure 8 , it can be seen that the stress distribution area of the chiral structure is more uniform, and the failure mode is not severe, which shows that the addition of the chiral feature can effectively improve the deformation stability and relieve the stress concentration problem.

[0039] Referring to Figure 9 and Figure 10It can be seen that, on the basis of chiral structure, appropriate addition of local chiral optimization features can make the deformation mode more uniform and stable, and the stress distribution area more extensive, which also verifies the correlation between the improvement of bearing capacity and the optimization of chiral structure.

[0040] In Figure 8 , Figure 9 、 Figure 10 , EXP represents the deformation picture of the actual static compression test, and FEM represents the deformation simulation picture obtained when the finite element model is simulated.

[0041] It should be noted that although there is a difference between the stress cloud picture of the simulation model and the actual experimental deformation mode, the data obtained by the simulation model still has sufficient reference value due to the establishment of the ideal finite element model and the defects of printing preparation.

[0042] The effect diagram of the structure applied to the energy absorption box can be seen from Figure 11 When the car encounters a collision accident, the energy absorption box filled with the traditional honeycomb structure 1 on the bumper will be impacted, and the dot matrix structure inside the energy absorption box will dissipate most of the impact energy through strain, only a small amount of energy will be transmitted to the bumper through the energy absorption box, but the initial peak force is still too high at this time, and due to the interaction of force, it will cause safety problems to the driver, and at this time the energy absorption effect of the energy absorption box is weak and needs to be improved.

[0043] After the filled structure is chiralized, the energy absorption box filled with the single chiral structure 2 can effectively reduce the initial peak force, improve the safety of the driver, and effectively stabilize the deformation of the energy absorption box, so as to avoid the phenomenon of stress concentration and cause the bumper to be damaged.

[0044] After the final optimization of the double chiral structure, under the action of the same impact load, the energy absorption box filled with the double chiral structure will not appear catastrophic collapse, and the energy absorption efficiency can be greatly improved, and the initial peak force is also greatly reduced compared with the traditional structure THS, while ensuring the safety of the driver, the damage is concentrated on the energy absorption box and the bumper beam, and only these standard parts need to be replaced during maintenance, while the expensive front and rear longitudinal beams and the main body structure of the vehicle body can be preserved, thereby significantly reducing the maintenance cost.

Claims

1. A method for preparing a filled biomimetic dissymmetrical structure automotive energy absorption box, characterized in that, It comprises the following steps: Step one, by combining chiral characteristics, single chiral feature optimization and multi-chiral feature optimization are carried out on the basis of traditional honeycomb structure; Step two, based on three-dimensional modeling software, models of four kinds of biomimetic chiral structures are established, including single chiral structure, double chiral structure A, double chiral structure B and double chiral structure C; Step three, the four kinds of biomimetic chiral structure models designed in step two are imported into three-dimensional printing software, and the preparation of TC4 material biomimetic chiral structure is completed based on selective laser melting technology; Step four, the prepared biomimetic chiral structure is filled into the inside of the automobile energy absorption box.

2. The method according to claim 1, wherein the method is characterized by, The design method of the single chiral structure is as follows: Based on the front reference surface, a regular hexagon contour is drawn and stretched, the stretching direction is defined as the Z axis, forming a regular hexagonal sheet structure, then a regular hexagon with rounded corners is drawn on the regular hexagonal sheet structure with the same center point as the regular hexagon and the six sides parallel to each other, the size of the regular hexagon with rounded corners is smaller than the hexagonal sheet structure, and the regular hexagonal sheet structure with a regular hexagonal hole with rounded corners in the middle is formed by cutting off the regular hexagonal structure part with rounded corners on the hexagonal sheet structure; Based on the front reference surface, the six corners of the regular hexagonal sheet structure are named, starting from the top corner on the left side, the corners are defined as A, B, C, D, E and F in clockwise direction, then the regular hexagonal sheet structure is arrayed along the Z axis direction three times; After arraying, the regular hexagonal sheet is defined as first sheet, second sheet, third sheet and fourth sheet from top to bottom; Based on the E point of the first sheet and the D point of the second sheet, a straight line is drawn, which is used as a guide line, then a circular contour is drawn and scanned on the guide line using the circular contour, establishing the first rib entity; Based on the upper reference surface, the first rib entity is circumferentially arrayed six times with the center point of the regular hexagonal sheet structure, so that each vertex of the bottom surface of the first sheet and the top surface of the second sheet is connected with the first rib entity; Based on the D point of the second sheet and the E point of the third sheet, a straight line is drawn, which is used as a guide line, then a circular contour is drawn and scanned on the guide line using the circular contour, establishing the second rib entity; Based on the front reference surface, the second rib entity is circumferentially arrayed six times with the center point of the regular hexagonal sheet structure, so that each vertex of the bottom surface of the second sheet and the top surface of the third sheet is connected with the second rib entity; The rib entity between the third sheet and the fourth sheet is the same as the first rib entity, and the four sheets and three groups of rib entities together constitute a single chiral structure monomer; The single chiral structure monomer is arrayed along the straight lines AE, CE and FD once, and then arrayed along the straight lines EA, EC and DF once, and finally the single chiral structure is obtained.

3. The method according to claim 1, wherein the method is characterized by, The design method of the double chiral structure A type is as follows: Draw two circles with diameters D1 and D2, and D1 is greater than 2D2, draw a helix based on the circle with diameter D1, the pitch of the helix is c1, the number of turns is 1, and the initial angle is set to 180°, wherein the length of the helix in the vertical direction is the same as the length of the guide line between the first thin plate and the second thin plate, scan the helix using a circle with diameter D2 to establish an A-type rib structure, and then perform central symmetry on the A-type rib structure based on the center of the circle with diameter D1 to obtain an A-type double-rib structure; Replace the first rib entity and the second rib entity with the A-type double-rib structure to obtain a chiral structure A monomer; Array the chiral structure A monomer along the straight lines AE, CE, and FD once, and then array the chiral structure A monomer along the straight lines EA, EC, and DF once to finally obtain a chiral structure A.

4. The method according to claim 1, wherein the method is characterized by, The design method of the chiral structure B is as follows: Draw two circles with diameters D1 and D2 based on the upper reference surface, and D1 is greater than 2D2, draw a helix based on the circle with diameter D1, the pitch of the helix is c2, the number of turns is 2, and the initial angle is 180°, wherein the length of the helix in the vertical direction is the same as the length of the guide line between the first thin plate and the second thin plate, project the helix on the front reference surface to obtain a scanning curve, and then scan the scanning curve using a circle with diameter D2 to establish a B-type rib structure; Based on the front reference surface, draw a vertical line passing through the center of the circle with diameter D1, project the vertical line onto the plane where the scanning curve is located to obtain a projection line, define the plane where the vertical line and the projection line are located as a reference plane, and mirror the B-type rib structure based on the reference plane to obtain a B-type double-rib structure; Replace the first rib entity and the second rib entity with the B-type double-rib structure to obtain a chiral structure B monomer; Array the chiral structure B monomer along the straight lines AE, CE, and FD once, and then array the chiral structure B monomer along the straight lines EA, EC, and DF once to finally obtain a chiral structure B.

5. The method according to claim 1, wherein the method is characterized by, The design method of the chiral structure C is as follows: Draw two circles with diameters D1 and D2 based on the upper reference surface, and D1 is greater than 2D2, draw a helix based on the circle with diameter D1, the pitch of the helix is c3, the number of turns is 1.5, and the initial angle is 180°, wherein the length of the helix in the vertical direction is the same as the length of the guide line between the first thin plate and the second thin plate, project the helix on the front reference surface to obtain a scanning curve, and then scan the scanning curve using a circle with diameter D2 to establish a C-type rib structure; Based on the front reference surface, draw a vertical line passing through the center of the circle with diameter D1, project the vertical line onto the plane where the scanning curve is located to obtain a projection line, define the plane where the vertical line and the projection line are located as a reference plane, and mirror the C-type rib structure based on the reference plane to obtain a C-type double-rib structure; Replace the first rib entity and the second rib entity with the C-type double-rib structure to obtain a chiral structure C monomer; The chiral structure C monomer is arrayed along the straight lines AE, CE and FD once, and then the chiral structure C monomer is arrayed along the straight lines EA, EC and DF once, and finally the chiral structure C is obtained.

6. The method of claim 1, wherein the method is characterized by: The preparation method in the step three is a selective laser melting technology, the particle size range of the selected TC4 powder is 15-53 microns, the used laser power is 180 w, the scanning speed is 800 mm / s, the layer thickness is 20 microns, and the interval is 60 microns.

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