Design method of honeycomb aluminum barrier finite element model

Abstract

The invention discloses a design method of a honeycomb aluminum barrier finite element model. The method comprises the following steps: equivalently converting the pore size of real honeycomb aluminum into the pore size of finite element honeycomb aluminum; calculating the initial wall thickness of the honeycomb aluminum unit in the equivalent finite element model; differentiated grid division is carried out based on the single-layer and double-layer thickness of the hexagonal honeycomb aluminum; calculating the failure force of a beam unit in the equivalent finite element model based on the axial fracture failure force of the real honeycomb aluminum collision barrier mucilage glue; and based on the aperture size, the initial wall thickness, the result of the differential grid division and the failure force of the beam unit, establishing a finite element model of the aluminum honeycomb part in the primary collision barrier. Through the processing scheme disclosed by the invention, the model calculation precision can be improved, the real deformation condition of the honeycomb aluminum counterguard can be reflected, the calculation efficiency can be improved, the simulation development time of the vehicle can be reduced, and the method can be suitable for the development of different honeycomb aluminum finite element counterguards.

Description

Technical Field

[0001] The invention relates to the technical field of finite element models, and in particular to a design method for a honeycomb aluminum barrier finite element model. Background Art

[0002] In order to reduce the injuries to passengers after a car accident, the safety performance of the car is a performance that must be considered in the design of the car model. In the initial stage of car model development, car companies need to develop vehicles according to the collision test requirements of different countries. Such tests often include honeycomb aluminum barriers suitable for their own national conditions. Standardized honeycomb aluminum barriers are used for collision tests to replace the scene of two real cars colliding on the actual road, reflecting the safety performance of the car under the collision of two cars. In order to optimize the collision safety performance in the vehicle data design stage, save the cost of real car collision tests and shorten the development cycle, a large number of automobile collision finite element simulation analyses are required. In this case, the development of a high-precision and high-efficiency honeycomb aluminum barrier finite element model is particularly important in the optimization of vehicle collision safety performance.

[0003] The existing honeycomb aluminum barrier models are often established through solid units or shell units. The finite element honeycomb aluminum model established with solid units can reduce the size of the model to a certain extent and improve the calculation speed, but it cannot reflect the deformation and failure mode of the real honeycomb aluminum structure during the collision process. Therefore, the barrier model established with solid units has low accuracy. Some finite element honeycomb aluminum models established with shell units are established with the same aperture size as the physical honeycomb aluminum. However, due to the small aperture of the physical honeycomb aluminum, there are too many units in this type of model, and the calculation efficiency is low, which affects the progress of vehicle development.

[0004] In order to balance the calculation accuracy and efficiency of the finite element barrier and form a scientific and complete finite element honeycomb aluminum barrier development system, the present invention proposes a design method for a honeycomb aluminum barrier finite element model with high accuracy and high efficiency. Summary of the invention

[0005] In view of this, an embodiment of the present disclosure provides a design method for a honeycomb aluminum barrier finite element model to develop a high-precision and high-efficiency finite element barrier model that meets barrier design specifications, thereby at least partially solving the problems existing in the prior art.

[0006] The present disclosure provides a method for designing a finite element model of a honeycomb aluminum barrier, the method comprising the following steps:

[0007] Convert the physical honeycomb aluminum aperture size into the finite element honeycomb aluminum aperture size;

[0008] Calculate the initial wall thickness of the honeycomb aluminum unit in the equivalent finite element model;

[0009] Differentiated meshing is performed based on the single and double layer thickness of hexagonal honeycomb aluminum;

[0010] The failure force of the beam unit in the equivalent finite element model is calculated based on the axial fracture failure force of the adhesive of the physical honeycomb aluminum collision barrier;

[0011] Establishing a finite element model of the honeycomb aluminum part of the initial version of the collision barrier based on the aperture size, the initial wall thickness, the result of the differentiated meshing and the failure force of the beam unit;

[0012] The finite element model of the rigid component is established based on preset parameters; the finite element model of the honeycomb aluminum part is connected to the finite element model of the rigid component by simulating bolts in a fixed connection manner.

[0013] According to a specific implementation of the embodiment of the present disclosure, the physical honeycomb aluminum aperture size is equivalently converted into the finite element honeycomb aluminum aperture size based on the following formula:

[0014] ;

[0015] in, is the total number of nodes on the cross section of the honeycomb aluminum block; L is the length of the honeycomb aluminum monomer structure; W is the width of the honeycomb aluminum monomer structure; It is the pore size of a single honeycomb aluminum after equivalent conversion.

[0016] According to a specific implementation of the embodiment of the present disclosure, the aperture size is 25-40 mm.

[0017] According to a specific implementation of the embodiment of the present disclosure, the initial wall thickness of the honeycomb aluminum unit in the equivalent finite element model is calculated based on the following formula:

[0018] ;

[0019] Among them, S is the static crushing strength; S0 is the material yield strength; d is the initial wall thickness of the simulated honeycomb aluminum monomer, It is the pore size of a single honeycomb aluminum after equivalent conversion.

[0020] According to a specific implementation of the embodiment of the present disclosure, the differentiated grid division based on the single and double layer thickness of the hexagonal honeycomb aluminum includes:

[0021] At the honeycomb aluminum edge with two layers of thickness, three differentiated grids are used, the larger one in the middle and the smaller ones on the two sides;

[0022] The small grid size of the tearing area at both ends is set to a; at the edge of the single-layer honeycomb aluminum, three evenly divided grids are used, and the grid size is ; The mesh size in the middle area is , limit the small grid size ;

[0023] The length Z of a single wrinkle crushed by the actual honeycomb aluminum is used to determine the longitudinal grid size of the simulated honeycomb aluminum monomer.

[0024] According to a specific implementation of the embodiment of the present disclosure, the small grid size a is 2-5 mm.

[0025] According to a specific implementation of the embodiment of the present disclosure, the failure force of the beam unit in the equivalent finite element model is calculated based on the axial fracture failure force of the adhesive of the physical honeycomb aluminum collision barrier by the following formula, including:

[0026] f=PLW / N;

[0027] Among them, f is the axial fracture failure force; P is the tensile strength of the adhesive; N is the total number of nodes on the cross section of the honeycomb aluminum block, that is, the number of beam units per unit area; L is the length of the honeycomb aluminum monomer structure; W is the width of the honeycomb aluminum monomer structure.

[0028] According to a specific implementation of the embodiment of the present disclosure, the method further includes:

[0029] Verification of the overall dynamic mechanical properties of the barrier, including:

[0030] The finite element model of the honeycomb aluminum part of the initial crash barrier was fixed to the rigid wall;

[0031] A specific type of tubular impactor impacts the honeycomb aluminum collision barrier at a speed of 60 km / h, and the tubular impactor overlaps the surface of the honeycomb aluminum collision barrier by 800 mm;

[0032] Conduct collision simulation analysis on tubular impactors;

[0033] Among them, when the overall dynamic simulation force and displacement curve of the honeycomb aluminum collision barrier is less than a preset threshold within the deformation and displacement range of the honeycomb aluminum collision barrier, the thickness of the honeycomb aluminum unit within the displacement range is increased; when the overall simulation force and displacement curve of the honeycomb aluminum collision barrier is greater than a preset threshold within the deformation and displacement range of the honeycomb aluminum collision barrier, the thickness of the honeycomb aluminum unit within the displacement range is reduced; the mechanical properties of the initial version of the honeycomb aluminum collision barrier are iteratively verified until the force and displacement characteristics meet the preset requirements.

[0034] The design method of the honeycomb aluminum barrier finite element model in the disclosed embodiment can not only improve the calculation accuracy of the model and reflect the actual deformation of the honeycomb aluminum barrier, but also reproduce the local tearing failure mode of the honeycomb aluminum with high precision. At the same time, the equivalent simplification of the honeycomb aluminum model can improve the calculation efficiency of the honeycomb aluminum barrier model and reduce the simulation analysis and development time of the vehicle. Through this design method, a development system of similar honeycomb aluminum barrier finite element models is formed, which can be applied to the development of different honeycomb aluminum finite element barriers. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0036] Figure 1 A schematic diagram of a design method flow of a honeycomb aluminum barrier finite element model provided in an embodiment of the present disclosure;

[0037] Figure 2 A schematic diagram of the overall process of a design method of a honeycomb aluminum barrier finite element model provided in an embodiment of the present disclosure;

[0038] Figure 3 A schematic diagram of a MPDB mobile honeycomb aluminum collision barrier provided in an embodiment of the present disclosure;

[0039] Figure 4 A schematic diagram of a honeycomb aluminum monomer structure and a regular hexagon provided in an embodiment of the present disclosure;

[0040] Figure 5 A schematic diagram of the composition of an MPDB barrier structure provided in an embodiment of the present disclosure;

[0041] Figure 6 A schematic diagram of the dimensions of a MPDB barrier honeycomb aluminum part provided in an embodiment of the present disclosure;

[0042] Figure 7 A schematic diagram of the crushing strength performance requirements of an MPDB barrier honeycomb aluminum monomer 2 provided in an embodiment of the present disclosure;

[0043] Figure 8 A honeycomb aluminum cross-section node number N and aperture provided in the embodiment of the present disclosure Function relationship graph;

[0044] Fig. 9 A schematic diagram of the difference division and size of a honeycomb aluminum grid provided in an embodiment of the present disclosure;

[0045] Fig.10 A schematic diagram of simulating gluing of a honeycomb aluminum beam unit provided in an embodiment of the present disclosure;

[0046] Fig.11 A schematic diagram of the composition of a preliminary MPDB honeycomb aluminum barrier structure provided in an embodiment of the present disclosure;

[0047] Fig.12 A finite element model diagram of a MPDB mobile honeycomb aluminum barrier provided in an embodiment of the present disclosure;

[0048] Fig.13A schematic diagram of a dynamic impact working condition of an MPDB barrier provided in an embodiment of the present disclosure;

[0049] Fig.14 A schematic diagram of a channel requirement for dynamic mechanical impact characteristics of an MPDB barrier provided in an embodiment of the present disclosure;

[0050] Fig.15 A schematic diagram of the mechanical properties of a developed MPDB barrier provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0051] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0052] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0053] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement a device and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein may be used to implement this device and / or practice this method.

[0054] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0055] The present invention discloses a design method for a finite element model of a honeycomb aluminum barrier. By analyzing the technical specifications of the actual barrier design, the barrier structure composition, size, material parameters and mechanical performance requirements are analyzed; taking into account both the calculation efficiency and the simulation accuracy, a reasonable honeycomb aluminum aperture conversion system is determined, and the aperture size of the actual structure is equivalent to the aperture size in the finite element model; the initial thickness of the honeycomb aluminum monomer in the finite element model is determined by combining the equivalent aperture size, the mechanical performance requirements of the honeycomb aluminum and the honeycomb aluminum crushing strength formula; considering the local deformation mode of the experimental honeycomb aluminum structure, a differentiated grid size division method is adopted for honeycomb aluminums of different thicknesses, and the length of the actual honeycomb aluminum crushing folds is referred to determine the initial thickness of the honeycomb aluminum monomer in the finite element model. The longitudinal grid division size of the simulated honeycomb aluminum monomer is determined; the beam unit is used to simulate the adhesive connection between the honeycomb aluminum and the back plate, and the failure force of the beam unit is determined according to the tensile test of the honeycomb aluminum monomer and the formula derivation; the shell unit is used to simulate the connecting plate and the mounting plate structure in the barrier, and the honeycomb aluminum monomer, the connecting plate, the mounting plate and the mobile trolley are assembled into an integral barrier structure to obtain the initial finite element barrier model; the initial barrier model is simulated and analyzed, the force-displacement curve of the simulation model is compared with the barrier mechanics design specifications, the thickness of the finite element barrier model is adjusted, and the mechanical properties of the initial barrier are iteratively verified until the barrier technical specifications are met, and the development of the overall finite element barrier model of honeycomb aluminum is completed.

[0056] Figure 1 A schematic diagram of the design method flow of the honeycomb aluminum barrier finite element model provided in an embodiment of the present disclosure.

[0057] Figure 2 For Figure 1 Schematic diagram of the overall process of the design method of the corresponding honeycomb aluminum barrier finite element model.

[0058] like Figure 2 As shown, first of all, the honeycomb aluminum collision barrier is mainly composed of deformable honeycomb aluminum and rigid trolley / rigid wall. The honeycomb aluminum connected to the rigid trolley is a mobile honeycomb aluminum collision barrier, and the honeycomb aluminum connected to the rigid wall is a fixed honeycomb aluminum collision barrier. The honeycomb aluminum structure is usually a regular hexagonal structure with different apertures. The honeycomb aluminum is formed by two pieces of stretched aluminum foil connected together by gluing, and has a double thickness at the gluing position. The honeycomb aluminum barrier is developed based on a large amount of vehicle model statistical data, which can reflect the vehicle model structure and mechanical strength characteristics in a specific area. In order to accurately develop the CAE finite element barrier, it is first necessary to investigate and collect relevant information on the physical barrier, analyze the physical barrier design technical specifications, and analyze the barrier structure composition, dimensional parameters and mechanical performance requirements.

[0059] More specifically, we collected relevant information about the MPDB barrier, analyzed the technical specifications of the physical barrier design, and analyzed the barrier structure composition, structural dimensions, material parameters and mechanical performance requirements. According to the MPDB barrier design specifications, it is known that it consists of a deformable honeycomb aluminum part and a mobile trolley part, such as Figure 3As shown. The aperture of the honeycomb aluminum structure is a regular hexagon. The honeycomb aluminum is formed by two pieces of stretched aluminum foil connected together by gluing, and has a double-layer thickness at the gluing position, such as Figure 4 As shown. The structure of the MPDB barrier honeycomb aluminum part can be referred to Figure 5 , the structural dimensions of the honeycomb aluminum part are as follows Figure 6 , material and thickness information are shown in Table 1.

[0060] Table 1

[0061] Structural parts Material thickness Honeycomb aluminum monomer 1 Aluminum 3003 Not given Honeycomb aluminum monomer 2 Aluminum 3003 Not given Honeycomb aluminum monomer 3 Aluminum 3003 Not given Package board Aluminum 5754 0.8mm Connecting plate 1 Aluminum 1050A 1.5mm Connecting plate 2 Aluminum 5754 0.5mm Connecting plate 3 Aluminum 5754 0.5mm Mounting Plate Aluminum AlMg2 or AlMg3 3mm

[0062] According to the technical specifications of the barrier, in terms of mechanical properties, the crushing strength of the honeycomb aluminum monomer 1 during static compression is 0.342 MPa +0% -10%, with a median value of 0.3249 MPa, and the crushing strength of the honeycomb aluminum monomer 3 during static compression is 1.711 MPa +0% -10%, with a median value of 1.6255 MPa. The crushing strength of the honeycomb aluminum monomer 2 during static compression is a gradual value, and its crushing strength requirement is as follows: Figure 7 The mechanical channel is within the upper and lower limits shown.

[0063] like Figure 1 As shown, at step S110, the aperture size of the physical honeycomb aluminum is equivalently converted into the aperture size of the finite element honeycomb aluminum.

[0064] In the embodiment of the present invention, the physical honeycomb aluminum aperture size is equivalently converted into the finite element honeycomb aluminum aperture size based on the following formula:

[0065] ;

[0066] in, is the total number of nodes on the cross section of the honeycomb aluminum block; L is the length of the honeycomb aluminum monomer structure; W is the width of the honeycomb aluminum monomer structure; It is the pore size of a single honeycomb aluminum after equivalent conversion.

[0067] In the embodiment of the present invention, the aperture size is 25-40 mm.

[0068] More specifically, the honeycomb aluminum barrier is usually composed of two or more honeycomb aluminum monomers with different mechanical properties. There is a mounting back plate between the different honeycomb aluminum monomers, and the honeycomb aluminum monomers are connected to the back plate by adhesive. In order to improve the calculation efficiency and ensure the calculation accuracy of the model, it is necessary to determine a reasonable conversion system to convert the physical honeycomb aluminum aperture size into the finite element honeycomb aluminum aperture size. Set the length and width of a specific honeycomb aluminum monomer structure to L and W respectively, and set the aperture size of a single honeycomb aluminum after equivalent conversion to , the number of honeycombs in the length direction is m, and the number of honeycombs in the width direction is n, then the calculation formula is as follows:

[0069] (1)

[0070] (2)

[0071] The total number of nodes on the cross section of the honeycomb aluminum block in this area is recorded as N, and N is the result of the following calculation:

[0072] N = (m + 1) (2n + 1) (3)

[0073] Combining formulas (1), (2), and (3), we can get the total number of nodes N and the aperture of the honeycomb aluminum: The relationship between:

[0074] (4)

[0075] From formula (4), we can see that the total number of nodes N is a hyperbolic function, and its function curve characteristics are: when the aperture When the value is infinitely small, the total number of nodes N is infinite, which corresponds to a large number of model nodes, reducing the model calculation efficiency. When the value is infinite, the total number of nodes N is an infinitesimal value, and the number of corresponding model nodes is very small, which reduces the calculation accuracy of the model. Considering the calculation efficiency and analysis accuracy comprehensively, it is necessary to find the inflection point range in the functional relationship of formula (4) as the aperture optimization area, and select the appropriate honeycomb aluminum aperture size within this optimization area. , a certain integer value including but not limited to the numerical value in the preferred region can be taken as the pore size of the honeycomb aluminum in the equivalent model.

[0076] For example, the aperture sizes of MPDB barrier honeycomb aluminum monomers are different. The aperture size of honeycomb aluminum monomer 1 is 19.1mm, the aperture size of honeycomb aluminum monomer 2 is 9.5mm, and the aperture size of honeycomb aluminum monomer 3 is 6.35mm. The aperture values ​​of each monomer are relatively small. If the model is built according to the actual size, the number of grid units in the monomer model will be too large, which will affect the calculation efficiency of the model. In order to take into account both calculation accuracy and calculation efficiency, the MPDB physical honeycomb aluminum aperture size is equivalently converted into the finite element honeycomb aluminum aperture size. Taking honeycomb aluminum monomer 1 as an example, its length L and width W are 1000mm and 570mm respectively. Substituting into formula (4), it can be seen that the total number of nodes N on the honeycomb aluminum cross section is related to the equivalent aperture The functional relationship curve is as follows Figure 8 As shown. Figure 8 It can be seen that when the aperture When the value is 15mm, the number of nodes is 702. When the value is 55mm, the number of nodes is 64 and the aperture is Inversely proportional to the number of nodes N, considering the calculation efficiency and analysis accuracy, the range of 25 to 40 mm is selected as the preferred area of ​​the aperture, such as 28 mm, 30 mm, 32 mm, 34 mm, including but not limited to these values. For the MPDB barrier in this application example, 30 mm is selected as an illustration of this application example.

[0077] More specifically, the process proceeds to step S120.

[0078] In step S120 , the initial wall thickness of the honeycomb aluminum unit in the equivalent finite element model is calculated.

[0079] In an embodiment of the present invention, the initial wall thickness of the honeycomb aluminum unit in the equivalent finite element model is calculated based on the following formula:

[0080] ;

[0081] Among them, S is the static crushing strength; S0 is the material yield strength; d is the initial wall thickness of the simulated honeycomb aluminum monomer, It is the pore size of a single honeycomb aluminum after equivalent conversion.

[0082] More specifically, in the design requirements of the honeycomb aluminum barrier structure, different honeycomb aluminum monomers have predetermined static mechanical performance requirements, such as requiring the static crushing strength of the honeycomb aluminum monomer to meet a certain numerical range. When the honeycomb aluminum material and aperture are determined, combined with the crushing strength requirements of the honeycomb aluminum monomer, the static compression strength calculation formula (5) of the honeycomb aluminum can be used to confirm the initial wall thickness d of the honeycomb aluminum unit in the equivalent finite element model:

[0083] (5)

[0084] Where S is the static crushing strength, S0 is the material yield strength, d is the initial wall thickness of the simulated honeycomb aluminum monomer, It is the aperture of a single honeycomb aluminum after equivalent conversion. For the honeycomb aluminum monomer structure with constant static crushing force value in the barrier design technical specification, the honeycomb aluminum unit wall thickness is a fixed value. For the honeycomb aluminum monomer structure with gradual static crushing force value in the barrier design technical specification, the honeycomb aluminum unit barrier can also be designed as a gradual value.

[0085] For example, with respect to the static mechanical performance requirements of MPDB honeycomb aluminum, when the honeycomb aluminum is made of 3003 aluminum and the aperture is set to 30mm, combined with the calculation formula (5) for the static compression strength of honeycomb aluminum, the initial wall thickness d of the honeycomb aluminum unit in the equivalent finite element model can be confirmed. For example, for honeycomb aluminum monomer 1, according to its median crushing strength of 0.3249MPa, aperture of 30mm and static yield strength of 0.118Mpa, it can be known that the wall thickness d of honeycomb aluminum monomer 1 is 0.25mm. Similarly, it can be obtained that the wall thickness d of honeycomb aluminum monomer 3 is 0.73mm under the same aperture. The static crushing force requirement of honeycomb aluminum monomer 2 is a gradual value, and the median value linearly changes from 0.686MPa to 1.02MPa. Similarly, it can be obtained that the wall thickness of honeycomb aluminum monomer 2 linearly changes from 0.41mm to 0.54mm.

[0086] Next, go to step S130.

[0087] In step S130, differentiated grid division is performed based on the single and double layer thickness of the hexagonal honeycomb aluminum.

[0088] In the embodiment of the present invention, the differentiated grid division based on the single and double layer thickness of the hexagonal honeycomb aluminum includes: at the honeycomb aluminum edge with two layers of thickness, three differentiated grids with a large middle and small two sides are used; wherein the small grid size of the tearing area at both ends is set to a; at the honeycomb aluminum edge with a single layer of thickness, three evenly divided grids are used, and the grid size is ; The mesh size in the middle area is , limit the small grid size The length Z of a single wrinkle crushed by the actual honeycomb aluminum is used to determine the longitudinal grid size of the simulated honeycomb aluminum monomer.

[0089] In the embodiment of the present invention, the small grid size a is 2-5 mm.

[0090] More specifically, after confirming the equivalent honeycomb aluminum unit aperture and thickness dimensions, it is also necessary to determine the division method of the honeycomb aluminum grid. The traditional grid division method of the hexagonal honeycomb aluminum structure is uniform division, but after conducting a honeycomb aluminum monomer compression test, it was found that this method cannot accurately reflect the deformation and tearing characteristics of the local honeycomb aluminum structure.

[0091] In order to better conform to the deformation and tearing mode of the honeycomb aluminum unit, three differentiated grids with a large middle and small two sides are used at the honeycomb aluminum edge with two layers of thickness. At the honeycomb aluminum edge with a single layer of thickness, three evenly divided grids are used. The grid size in the longitudinal crushing direction of the honeycomb aluminum can be confirmed by the honeycomb aluminum monomer crushing test, and the longitudinal grid division size of the simulated honeycomb aluminum monomer is determined according to the length Z of a single wrinkle crushed by the actual honeycomb aluminum, so as to more closely reflect the crush wrinkle deformation of the honeycomb aluminum. Through steps S110 and S120, the different honeycomb aluminum monomers in the entire barrier can be equivalent, and the construction of the finite element model of the honeycomb aluminum monomer can be completed.

[0092] For example, a compression test is performed on the MPDB barrier honeycomb aluminum monomer 1, and the compression deformation is as follows: Fig. 9 As shown, it can be seen that at the honeycomb aluminum edge with two layers of thickness (corresponding to Fig. 9 (1) Blue area), after deformation, the middle area of ​​the honeycomb aluminum is relatively intact, and the two end areas are torn. Three differentiated grids with a large middle area and small two sides can be used. For the small grids divided in the torn areas at both ends, the small grid size a can be set to include but not limited to 2, 3, 4, 5 mm, and the grid size in the middle area is At the edge of the single-layer honeycomb aluminum (corresponding to Fig. 9 (1) Green area), the deformation and tearing of honeycomb aluminum are relatively uniform, and three evenly divided grids can be used, that is, the grid size is The grid size in the longitudinal crushing direction of the honeycomb aluminum can be determined according to the deformation of the honeycomb aluminum crushing folds (such as Fig. 9 (3) As shown in FIG. 3 ), if the length Z of a single wrinkle in the test is 5 mm, the grid size in the crushing direction is set to 5 mm. The equivalent transformation of the finite element model of the honeycomb aluminum monomer 1 can be completed in the above manner. Similarly, the finite element models of the honeycomb aluminum monomers 2 and 3 can be established.

[0093] Next, go to step S140.

[0094] In step S140, the failure force of the beam unit in the equivalent finite element model is calculated based on the axial fracture failure force of the adhesive of the physical honeycomb aluminum collision barrier.

[0095] In the embodiment of the present invention, the failure force of the beam unit in the equivalent finite element model is calculated based on the axial fracture failure force of the adhesive of the physical honeycomb aluminum collision barrier by the following formula, including:

[0096] f=PLW / N;

[0097] Among them, f is the axial fracture failure force; P is the tensile strength of the adhesive; N is the total number of nodes on the cross section of the honeycomb aluminum block, that is, the number of beam units per unit area; L is the length of the honeycomb aluminum monomer structure; W is the width of the honeycomb aluminum monomer structure.

[0098] More specifically, the honeycomb aluminum barrier usually connects honeycomb aluminum monomers of different structural sizes to the mounting backplane through adhesive. The adhesive may crack due to excessive force during the test. In order to reproduce the adhesive cracking phenomenon in the simulation, it is necessary to confirm the adhesive strength of the adhesive through testing. The tensile strength P of the adhesive can be measured by the standard test specification ASTM C297-61. The measurement method is: make a honeycomb aluminum test specimen with a length and width of 100×100 mm and a height of 15 mm, perform a plane tensile test to determine the fracture force of the adhesive, and divide it by the honeycomb aluminum test area to obtain the tensile strength P of the adhesive. In the finite element model of the honeycomb aluminum barrier, beam units are used to simulate the adhesive connection. A beam unit is set at each unit node, and the axial fracture failure force f is entered in the simulation keyword of the beam unit. The failure force can be obtained by dividing the tensile strength P by the number of beam units per unit area. The calculation formula is (6):

[0099] f = PLW / N (6)

[0100] For example, the honeycomb aluminum monomer is connected to the mounting backplane by adhesive. The adhesive may crack due to excessive force during the test. A beam unit is established in the simulation model for simulation. Fig.10 As shown, the failure force parameters of the beam unit are set to control its fracture. The failure force parameters of a single beam unit can be obtained as follows: Referring to the test specification ASTM C297-61, a honeycomb aluminum test specimen with a length and width of W×L and a height of 15 mm is prepared. A plane tensile test is performed on the specimen to determine the fracture force of the adhesive. The tensile strength P of the adhesive is obtained by dividing it by the honeycomb aluminum test area. The fracture failure force of the beam unit can be obtained by dividing it by the number of beam units per unit area N. Referring to the calculation formula (6), it can be obtained that the failure force of the beam unit can be set to 2.17 KN. The adhesive material of honeycomb aluminum monomers 1, 2 and 3 is the same, and the failure force parameters of the beam unit are set the same.

[0101] Next, go to step S150.

[0102] In step S150, a finite element model of the honeycomb aluminum part in the preliminary collision barrier is established based on the aperture size, the initial wall thickness, the result of the differentiated meshing and the failure force of the beam unit.

[0103] Next, go to step S160.

[0104] In step S160, a finite element model of the rigid component is established based on preset parameters; the finite element model of the honeycomb aluminum part is connected to the finite element model of the rigid component by simulating bolts in a fixed manner.

[0105] More specifically, after determining the modeling method of the honeycomb aluminum monomer and the adhesive, the back plate connected to the honeycomb aluminum in the barrier can be simulated using shell elements, and the thickness and material of the shell elements can be added according to the actual thickness and material of the back plate. By assembling the honeycomb aluminum monomer, adhesive and back plate into one in the finite element analysis software, the finite element model of the honeycomb aluminum part in the initial version of the collision barrier can be completed, such as Fig.11 .

[0106] The other part of the collision barrier is a rigid trolley or a rigid wall. The honeycomb aluminum part is connected to the rigid trolley / rigid wall by bolts. The finite element modeling of the rigid trolley can be carried out according to the overall size, wheelbase, weight and center of mass of the physical trolley. The bolt connection can be simulated by fixing in the finite element software. The honeycomb aluminum model and the rigid trolley model can be combined to complete the model development of the first version of the mobile honeycomb aluminum barrier. For barriers with the honeycomb aluminum part fixed on the rigid wall, a rigid plate can be established with shell elements, and rigid body materials can be added to the rigid plate and its six degrees of freedom can be constrained to simulate the rigid wall. Similarly, the honeycomb aluminum model and the rigid wall model can be combined in the finite element software by fixing, and the model development of the first version of the fixed honeycomb aluminum barrier can be completed.

[0107] For example, after determining the finite element simulation method of the honeycomb aluminum monomer and adhesive, the back plate connected to the honeycomb aluminum in the barrier can be simulated using shell elements. The average grid size can be divided into 20mm. The size setting is not a unique value, including but not limited to 20mm, 25mm, 30mm, 35mm. In the finite element model, the thickness and material of the shell element are added according to the actual thickness and material of the back plate. The established honeycomb aluminum monomer model, adhesive model and back plate model are connected as one in the finite element analysis software to complete the finite element model of the honeycomb aluminum part in the initial version of the collision barrier. Fig.11 The other part of the collision barrier is the honeycomb aluminum structure carrier, which is usually a trolley structure with great structural strength. The finite element modeling of the trolley structure can be carried out according to the overall size, wheelbase, weight and center of mass of the actual trolley. The honeycomb aluminum part and the trolley part are usually connected by bolts, and the simulation is carried out in the finite element software by means of fixed connection, such as Fig.11 Partial schematic diagram of the finite element model of the middle platform. The above steps can complete the model development of the initial version of the mobile honeycomb aluminum barrier.

[0108] In an embodiment of the present invention, verification of the overall dynamic mechanical properties of the barrier includes: fixing the finite element model of the honeycomb aluminum part in the initial version of the collision barrier on a rigid wall; a specific form of tubular impactor hits the honeycomb aluminum collision barrier at a speed of 60 km / h, and the tubular impactor overlaps the surface of the honeycomb aluminum collision barrier by 800 mm; performing collision simulation analysis on the tubular impactor; wherein, in the deformation and displacement interval of the honeycomb aluminum collision barrier, when the overall dynamic simulation force and displacement curve of the honeycomb aluminum collision barrier is less than a preset threshold, increasing the thickness of the honeycomb aluminum unit in the displacement interval; in the deformation and displacement interval of the honeycomb aluminum collision barrier, when the overall simulation force and displacement curve of the honeycomb aluminum collision barrier is greater than a preset threshold, reducing the thickness of the honeycomb aluminum unit in the displacement interval; iteratively verifying the mechanical properties of the initial version of the honeycomb aluminum collision barrier until the force and displacement characteristics meet the preset requirements, and the finite element model of the collision barrier completed by iterative verification is as follows: Fig.12 .

[0109] More specifically, in the technical specifications for honeycomb aluminum barriers, in addition to the static mechanical requirements for the honeycomb aluminum monomers, there are also certain range requirements for the dynamic mechanical properties of the honeycomb aluminum barrier as a whole. For example, when the barrier as a whole hits a rigid wall at a certain speed, the force and displacement characteristic curve of the barrier should be within the required mechanical channel. For this reason, after the initial version of the finite element honeycomb aluminum barrier model is completed, it is necessary to verify the dynamic mechanical properties of the barrier as a whole. If, within a certain section of the barrier deformation and displacement range, the overall dynamic simulation force and displacement curve of the honeycomb aluminum barrier is less than the channel requirements of the barrier technical specifications, the thickness of the honeycomb aluminum unit within the displacement range can be appropriately increased. If, within a certain section of the barrier deformation and displacement range, the overall simulation force and displacement curve of the honeycomb aluminum barrier is greater than the channel requirements of the barrier technical specifications, the thickness of the honeycomb aluminum unit within the displacement range can be appropriately reduced, and the mechanical properties of the initial version of the barrier are iteratively verified until the force-displacement characteristics meet the requirements of the barrier technical specifications, and the collision force-displacement curve of the developed honeycomb aluminum barrier is completed. Fig.15 .

[0110] For example, for the MPDB barrier, the dynamic requirement is: the honeycomb aluminum part of the MPDB barrier is fixed on the rigid wall, a specific type of tubular impactor hits the barrier at a speed of 60 km / h, and the tubular impactor overlaps the barrier surface by 800 mm. The collision diagram is shown in the figure below: Fig.13 As shown, the collision force-displacement curve of the honeycomb aluminum barrier should be located at Fig.14 To this end, a collision simulation analysis of a tubular impactor is conducted.

[0111] The design method of the honeycomb aluminum barrier finite element model proposed in the present invention establishes the honeycomb aluminum barrier finite element model through a new method on the basis of ensuring the calculation accuracy and calculation efficiency. Specifically, it is embodied in: determining the equivalent conversion method of the honeycomb aluminum structure size, and proposing a set of calculation formulas, which equivalently convert the honeycomb aluminum aperture and thickness on the basis of both calculation accuracy and efficiency. Considering the local deformation and tearing mode of the honeycomb aluminum unit, a differentiated grid division scheme at the single and double layer thickness of the hexagonal honeycomb aluminum is proposed. In order to accurately simulate the failure of the adhesive of the physical barrier, the simulation method of the adhesive in the finite element model and the calculation method and formula of the failure force simulation parameters are determined. After the establishment of the initial version of the finite element barrier model, a dynamic impact collision simulation verification is carried out, and the honeycomb aluminum structure parameters are adjusted until the mechanical properties meet the technical requirements. The design method provided by the present invention can not only improve the calculation accuracy of the model and reflect the actual deformation of the honeycomb aluminum barrier, but also improve the calculation efficiency, reduce the simulation development time of the vehicle, and can be applied to the development of different honeycomb aluminum finite element barriers.

[0112] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A design method for a finite element model of a honeycomb aluminum barrier, characterized in that: The method comprises the following steps: Convert the physical honeycomb aluminum aperture size into the finite element honeycomb aluminum aperture size; Calculate the initial wall thickness of the honeycomb aluminum unit in the equivalent finite element model; Differentiated meshing is performed based on the single and double layer thickness of hexagonal honeycomb aluminum; The failure force of the beam unit in the equivalent finite element model is calculated based on the axial fracture failure force of the adhesive of the physical honeycomb aluminum collision barrier; Establishing a finite element model of the honeycomb aluminum part of the initial version of the collision barrier based on the aperture size, the initial wall thickness, the result of the differentiated meshing and the failure force of the beam unit; The finite element model of the rigid component is established based on preset parameters; the finite element model of the honeycomb aluminum part is connected to the finite element model of the rigid component by simulating bolts in a fixed connection manner.

2. The design method of the finite element model of the honeycomb aluminum barrier according to claim 1 is characterized in that: The physical honeycomb aluminum aperture size is equivalently converted into the finite element honeycomb aluminum aperture size based on the following formula: ; in, is the total number of nodes on the cross section of the honeycomb aluminum block; L is the length of the honeycomb aluminum monomer structure; W is the width of the honeycomb aluminum monomer structure; It is the pore size of a single honeycomb aluminum after equivalent conversion.

3. The design method of the finite element model of the honeycomb aluminum barrier according to claim 2 is characterized in that: The aperture size is 25-40 mm.

4. The design method of the finite element model of the honeycomb aluminum barrier according to claim 1 is characterized in that: The initial wall thickness of the honeycomb aluminum unit in the equivalent finite element model is calculated based on the following formula: ; Among them, S is the static crushing strength; S0 is the material yield strength; d is the initial wall thickness of the simulated honeycomb aluminum monomer, It is the pore size of a single honeycomb aluminum after equivalent conversion.

5. The design method of the finite element model of the honeycomb aluminum barrier according to claim 1 is characterized in that: The differentiated grid division based on the single and double layer thickness of the hexagonal honeycomb aluminum includes: At the honeycomb aluminum edge with two layers of thickness, three differentiated grids are used, the larger one in the middle and the smaller ones on the two sides; The small grid size at both ends is set to a, and the grid size in the middle area is , limit the small grid size ; At the edge of the single-layer honeycomb aluminum, three evenly divided grids are used, and the grid size is ; The length Z of a single wrinkle crushed by the actual honeycomb aluminum is used to determine the longitudinal grid size of the simulated honeycomb aluminum monomer.

6. The design method of the finite element model of the honeycomb aluminum barrier according to claim 5 is characterized in that: The small grid size a is 2-5mm.

7. The design method of the finite element model of the honeycomb aluminum barrier according to claim 1 is characterized in that: The failure force of the beam unit in the equivalent finite element model is calculated based on the axial fracture failure force of the adhesive of the physical honeycomb aluminum collision barrier by the following formula, including: f=PLW / N; Among them, f is the axial fracture failure force; P is the tensile strength of the adhesive; N is the total number of nodes on the cross section of the honeycomb aluminum block, that is, the number of beam units per unit area; L is the length of the honeycomb aluminum monomer structure; W is the width of the honeycomb aluminum monomer structure.

8. The design method of the finite element model of the honeycomb aluminum barrier according to any one of claims 1 to 7, characterized in that: The method further comprises: Verification of the overall dynamic mechanical properties of the barrier, including: The finite element model of the honeycomb aluminum part of the initial crash barrier was fixed to the rigid wall; The tubular impactor hits the honeycomb aluminum collision barrier at a speed of 60 km / h, and the tubular impactor overlaps the surface of the honeycomb aluminum collision barrier by 800 mm; Conduct collision simulation analysis on tubular impactors; Among them, when the overall dynamic simulation force and displacement curve of the honeycomb aluminum collision barrier is less than a preset threshold within the deformation and displacement range of the honeycomb aluminum collision barrier, the thickness of the honeycomb aluminum unit within the displacement range is increased; when the overall simulation force and displacement curve of the honeycomb aluminum collision barrier is greater than a preset threshold within the deformation and displacement range of the honeycomb aluminum collision barrier, the thickness of the honeycomb aluminum unit within the displacement range is reduced; the mechanical properties of the initial version of the honeycomb aluminum collision barrier are iteratively verified until the force and displacement characteristics meet the preset requirements.

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