A Design Method for the Finite Element Model of a Honeycomb Aluminum Barrier

Abstract

The present invention discloses a design method for a finite element model of a honeycomb aluminum barrier. The method includes: equivalently converting the pore size of the physical honeycomb aluminum into the pore size of the finite element honeycomb aluminum; calculating the initial wall thickness of the honeycomb aluminum unit in the equivalent finite element model; performing differential mesh division based on the single and double layer thicknesses of the hexagonal honeycomb aluminum; calculating the failure force of the beam element in the equivalent finite element model based on the axial fracture failure force of the adhesive of the physical honeycomb aluminum collision barrier; and establishing a finite element model of the honeycomb aluminum part in the initial version of the collision barrier based on the pore size, the initial wall thickness, the result of the differential mesh division, and the failure force of the beam element. Through the processing solution disclosed in the present invention, the calculation accuracy of the model can be improved, the true deformation of the honeycomb aluminum barrier can be reflected, and the calculation efficiency can be improved, reducing the simulation development time of the vehicle, and it can be applied to the development of different honeycomb aluminum finite element barriers.

Description

Technical Field

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

[0002] To reduce the injury of vehicle occupants after a car accident, vehicle safety performance is a performance that must be considered in vehicle model design. In the initial stage of vehicle model research and development, vehicle manufacturers need to conduct vehicle research and development according to the collision test requirements of different countries. Such tests often include honeycomb aluminum barriers suitable for their own national conditions. Collision tests are carried out with standardized honeycomb aluminum barriers to replace the scenario of two real vehicles colliding on the actual road, reflecting the safety performance of the car under a two-vehicle head-on collision. In order to optimize the collision safety performance during the vehicle data design stage, save the cost of real vehicle collision tests and shorten the development cycle, a large number of finite element simulation analyses of vehicle collisions are required. In this case, developing a high-precision and high-efficiency finite element model of a honeycomb aluminum barrier is particularly important for optimizing the vehicle collision safety performance.

[0003] Currently, existing honeycomb aluminum barrier models are often established through solid elements or shell elements. The finite element honeycomb aluminum model established with solid elements can reduce the size of the model to a certain extent and improve the calculation speed, but it cannot reflect the deformation and failure modes of the real honeycomb aluminum structure during the collision process. Therefore, the accuracy of the barrier model established with solid elements is relatively low. Some finite element honeycomb aluminum models established with shell elements are established with the same aperture size as the physical honeycomb aluminum. However, due to the small aperture of the physical honeycomb aluminum, the number of elements in such models is too large, resulting in low calculation efficiency and affecting the progress of vehicle model development.

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

[0005] In view of this, the embodiments of the present disclosure provide a design method for a finite element model of a honeycomb aluminum barrier to develop a finite element barrier model with high precision and high efficiency that meets the barrier design specifications, and at least partially solve the problems existing in the prior art.

[0006] The embodiments of the present disclosure provide a design method for a finite element model of a honeycomb aluminum barrier, and the method includes the following steps:

[0007] Equivalently convert the aperture size of the physical honeycomb aluminum into the aperture size of the finite element honeycomb aluminum;

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

[0009] Differentially divide the grid based on the thickness of the single and double layers of hexagonal honeycomb aluminum;

[0010] Calculate the failure force of the beam element in the equivalent finite element model based on the axial fracture failure force of the physical honeycomb aluminum colliding with the wall barrier and the adhesive;

[0011] Establish a finite element model of the honeycomb aluminum part in the initial version of the collision wall barrier based on the aperture size, the initial wall thickness, the result of the differential grid division, and the failure force of the beam element;

[0012] Establish a finite element model of the rigid part based on preset parameters; the finite element model of the honeycomb aluminum part simulates bolts by means of fixed connection and is connected to the finite element model of the rigid part.

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

[0014] ;

[0015] Wherein, is the total number of nodes on the cross-section of the honeycomb aluminum block; L is the length of the single honeycomb aluminum structure; W is the width of the single honeycomb aluminum structure; is the aperture of a single honeycomb aluminum after equivalent conversion.

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

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

[0018] ;

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

[0020] According to a specific implementation manner of the embodiments of the present disclosure, the differential grid division based on the thickness of the single and double layers of hexagonal honeycomb aluminum includes:

[0021] At the edge of the honeycomb aluminum with two layers of thickness, adopt three differential grids that are large in the middle and small on both sides;

[0022] Among them, set the small grid size divided in the tearing area at both ends to a; at the edge of the honeycomb aluminum with a single layer of thickness, adopt three evenly divided grids, and the grid size is ; the grid size in the middle area is , and limit the small grid size ;

[0023] Determine the mesh size in the longitudinal direction of the simulated single honeycomb aluminum cell based on the length Z of a single fold crushed by the actual honeycomb aluminum.

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

[0025] According to a specific implementation manner of the embodiment of the present disclosure, calculate the failure force of the beam element in the equivalent finite element model based on the axial fracture failure force of the adhesive on the physical honeycomb aluminum colliding with the wall barrier through the following formula, including:

[0026] f = PLW / N;

[0027] Where, 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 elements per unit area; L is the length of the honeycomb aluminum single - cell structure; W is the width of the honeycomb aluminum single - cell structure.

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

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

[0030] Fix the finite element model of the honeycomb aluminum part in the initial version of the collision wall barrier on a rigid wall;

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

[0032] Conduct a collision simulation analysis on the tubular impactor;

[0033] Among them, within the deformation displacement range of the honeycomb aluminum collision wall barrier, when the overall dynamic simulation force - displacement curve of the honeycomb aluminum collision wall barrier is less than the preset threshold, increase the thickness of the honeycomb aluminum cells in this displacement range; within the deformation displacement range of the honeycomb aluminum collision wall barrier, when the overall simulation force - displacement curve of the honeycomb aluminum collision wall barrier is greater than the preset threshold, reduce the thickness of the honeycomb aluminum cells in this displacement range; iteratively verify the mechanical properties of the initial version of the honeycomb aluminum collision wall barrier until the force - displacement characteristics meet the preset requirements.

[0034] The design method of the honeycomb aluminum wall barrier finite element model in the embodiment of the present disclosure can not only improve the model calculation accuracy, reflect the real deformation situation of the honeycomb aluminum wall barrier, but also reproduce the local tearing failure mode of the honeycomb aluminum with high precision. At the same time, equivalent simplification of the honeycomb aluminum model can improve the calculation efficiency of the honeycomb aluminum wall barrier model and reduce the simulation analysis and development time of the vehicle. Through this design method, a development system for finite element models of similar honeycomb aluminum wall barriers is formed, which can be applied to the development of different honeycomb aluminum finite element wall barriers. Brief Description of the Drawings

[0035] The above is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, the following provides a more detailed description of the present invention in combination with the drawings and specific embodiments.

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

[0037] Figure 2 Schematic overall flow diagram of a design method for a finite element model of a honeycomb aluminum barrier provided by an embodiment of the present disclosure;

[0038] Figure 3 Schematic diagram of an MPDB mobile honeycomb aluminum collision barrier provided by an embodiment of the present disclosure;

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

[0040] Figure 5 Schematic diagram of the structural composition of an MPDB barrier provided by an embodiment of the present disclosure;

[0041] Figure 6 Schematic diagram of the dimensions of the honeycomb aluminum part of an MPDB barrier provided by an embodiment of the present disclosure;

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

[0043] Figure 8 Schematic diagram of the relationship between the number of cross-sectional nodes N of honeycomb aluminum and the pore diameter Function relationship curve graph;

[0044] Figure 9 Schematic diagram of the differential division and dimensions of the honeycomb aluminum grid provided by an embodiment of the present disclosure;

[0045] Figure 10 Schematic diagram of the simulation of the adhesive of the honeycomb aluminum beam element provided by an embodiment of the present disclosure;

[0046] Figure 11 Schematic diagram of the structural composition of the initial version of the MPDB honeycomb aluminum barrier provided by an embodiment of the present disclosure;

[0047] Figure 12 Schematic diagram of a finite element model of an MPDB mobile honeycomb aluminum barrier provided by an embodiment of the present disclosure;

[0048] Figure 13Schematic diagram of a dynamic impact condition of an MPDB barrier provided by an embodiment of the present disclosure;

[0049] Figure 14 Schematic diagram of channel requirements for dynamic mechanical impact characteristics of an MPDB barrier provided by an embodiment of the present disclosure;

[0050] Figure 15 Schematic diagram of mechanical characteristics of a developed MPDB barrier provided by an embodiment of the present disclosure. Detailed implementation manners

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

[0052] The following uses specific specific examples to illustrate the implementation manners of the present disclosure. Those skilled in the art can easily understand other advantages and effects of the present disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. The present disclosure can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts belong to the scope of protection of the present disclosure.

[0053] It should be noted that the following describes various aspects of embodiments within the scope of the appended claims. It should be obvious that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present disclosure, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement a device and / or practice a method. In addition, this device and / or this method can be implemented using other structures and / or functions in addition to one or more of the aspects described herein.

[0054] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the aspects can 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 design technical specifications of the physical barrier, the structural composition, dimensions, material parameters, and mechanical property requirements of the barrier are analyzed; taking into account the calculation efficiency and simulation accuracy, a reasonable honeycomb aluminum pore size conversion system is determined, and the pore size of the physical structure is equivalent to the pore size in the finite element model; combining the equivalent pore size, the mechanical property requirements of honeycomb aluminum, and the honeycomb aluminum crushing strength formula, the initial thickness of the honeycomb aluminum monomer in the finite element model is determined; considering the local deformation mode of the test honeycomb aluminum structure, different grid size division methods are adopted for honeycomb aluminum with different thicknesses, and the longitudinal grid division size of the simulated honeycomb aluminum monomer is determined with reference to the length of the actual honeycomb aluminum crushing fold; the beam element is used to simulate the adhesive connection between the honeycomb aluminum and the backboard, and the failure force of the beam element is determined according to the tensile test of the honeycomb aluminum monomer and formula derivation; the shell element is used to simulate the connection plate and mounting plate structures in the barrier, and the honeycomb aluminum monomer, connection plate, mounting plate, and moving trolley are assembled into an overall barrier structure to obtain the initial finite element barrier model; the initial barrier model is subjected to simulation analysis, the force-displacement curve of the simulation model is compared with the mechanical design specifications of the barrier, the thickness of the finite element barrier model is adjusted, and the mechanical properties of the initial barrier are iteratively verified until the requirements of the barrier technical specifications are met, and the development of the overall finite element barrier model of honeycomb aluminum is completed.

[0056] Figure 1 It is a schematic diagram of the design method flow of the finite element model of the honeycomb aluminum barrier provided by the embodiments of the present disclosure.

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

[0058] As Figure 2 shown, first of all, the honeycomb aluminum collision barrier is mainly composed of deformable honeycomb aluminum and a rigid trolley / rigid wall. The honeycomb aluminum connected to the rigid trolley is the moving honeycomb aluminum collision barrier, and the honeycomb aluminum connected to the rigid wall is the fixed honeycomb aluminum collision barrier. Among them, the honeycomb aluminum structure is usually a regular hexagon structure with different pore sizes. The honeycomb aluminum is formed by connecting two stretched aluminum foils together by means of adhesive, and has a double thickness at the adhesive position. The honeycomb aluminum barrier is developed based on a large amount of vehicle model statistical data and can reflect the structural and mechanical strength characteristics of vehicle models in a specific region. 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 design technical specifications of the physical barrier, and analyze the structural composition, dimensional parameters, and mechanical property requirements of the barrier.

[0059] More specifically, investigate and collect relevant information on the MPDB barrier, analyze the design technical specifications of the physical barrier, and analyze the structural composition, structural dimensions, material parameters, and mechanical property requirements of the barrier. According to the MPDB barrier design specifications, it can be known that it is composed of a deformable honeycomb aluminum part and a moving trolley part, as Figure 3As shown. The pore diameter of the honeycomb aluminum structure is a regular hexagon. The honeycomb aluminum is formed by connecting two pieces of stretched aluminum foils together by means of adhesive. There is a double-layer thickness at the adhesive position, such as Figure 4 shown. The composition of the partial structure of the honeycomb aluminum in the MPDB barrier can be referred to Figure 5 , and the dimensions of the partial structure of the honeycomb aluminum are as Figure 6 shown. The material and thickness information are shown in Table 1.

[0060] Table 1

[0061] Structural member 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 Encapsulation board Aluminum 5754 0.8 mm Connection board 1 Aluminum 1050A 1.5 mm Connection board 2 Aluminum 5754 0.5 mm Connection board 3 Aluminum 5754 0.5 mm Mounting board Aluminum AlMg2 or AlMg3 3 mm

[0062] According to the barrier technical specification, in terms of mechanical properties, the crushing strength of the honeycomb aluminum monomer 1 under static compression is 0.342 MPa +0% -10%, and the median value is 0.3249 MPa. The crushing strength of the honeycomb aluminum monomer 3 under static compression is 1.711 MPa +0% -10%, and the median value is 1.6255 MPa. The crushing strength of the honeycomb aluminum monomer 2 under static compression is a gradually changing value, and its crushing strength requirement is within the upper and lower limit ranges of the mechanical channel as Figure 7 shown.

[0063] Such as Figure 1 shown, at step S110, the pore diameter size of the physical honeycomb aluminum is equivalently converted into the pore diameter size of the finite element honeycomb aluminum.

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

[0065] ;

[0066] wherein 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; is the pore diameter of a single honeycomb aluminum after equivalent conversion.

[0067] In the embodiment of the present invention, the pore diameter 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 an installation backplane between different honeycomb aluminum monomers, and the honeycomb aluminum monomers are connected to the backplane by adhesive. To improve the calculation efficiency and ensure the model calculation accuracy, a reasonable conversion system needs to be determined to equivalently convert the pore diameter size of the physical honeycomb aluminum into the pore diameter size of the finite element honeycomb aluminum. Suppose the length and width of a specific honeycomb aluminum monomer structure are L and W respectively, and the pore diameter of a single honeycomb aluminum after equivalent conversion is , the number of honeycombs in the length direction is m, and the number of honeycombs in the width direction is n, then there is the following calculation formula:

[0069] (1)

[0070] (2)

[0071] The total number of nodes on the cross-section of the honeycomb aluminum block in this area is denoted as N, and N is the result calculated by the following formula:

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

[0073] Combining formulas (1), (2), and (3), the relationship between the total number of nodes N and the aperture of the honeycomb aluminum can be obtained as follows:

[0074] (4)

[0075] It can be seen from formula (4) that the total number of nodes N is a hyperbolic function, and the characteristics of its function curve are: when the aperture takes an infinitely small value, the total number of nodes N is an infinitely large value, corresponding to a large number of nodes in the model, reducing the calculation efficiency of the model. When takes an infinitely large value, the total number of nodes N is an infinitely small value, corresponding to a small number of nodes in the model, reducing the calculation accuracy of the model. Considering both the calculation efficiency and the analysis accuracy, it is necessary to find the inflection point range in the functional relationship of formula (4) as the preferred aperture area, and select an appropriate honeycomb aluminum aperture size within this preferred area , and an integer value included but not limited to within the preferred area can be taken as the honeycomb aluminum aperture size in the equivalent model.

[0076] For example, the aperture sizes of the honeycomb aluminum monomers of the MPDB wall barrier are different. The aperture size of honeycomb aluminum monomer 1 is 19.1 mm, the aperture size of honeycomb aluminum monomer 2 is 9.5 mm, and the aperture size of honeycomb aluminum monomer 3 is 6.35 mm. The aperture values of each monomer are relatively small. If modeled according to the actual size, the number of mesh units in the monomer model is too large, which affects the calculation efficiency of the model. To balance the calculation accuracy and efficiency, the aperture size of the MPDB physical honeycomb aluminum is equivalently transformed into the aperture size of the finite element honeycomb aluminum. Taking honeycomb aluminum monomer 1 as an example, its length L and width W are 1000 mm and 570 mm respectively. Substituting into formula (4), the functional relationship curve between the total number of nodes N on the cross-section of the honeycomb aluminum and the equivalent aperture is as shown in Figure 8 . It can be seen from Figure 8 that when the aperture takes a value of 15 mm, the number of nodes is 702, and when the aperture takes a value of 55 mm, the number of nodes is 64. The aperture It is inversely proportional to the number of nodes N. Considering both the calculation efficiency and analysis accuracy, the range of 25 to 40 mm is selected as the preferred area for the aperture diameter, 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 for the illustration of this application example.

[0077] More specifically, next, go to step S120.

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

[0079] In the 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] 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, is the aperture diameter 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 property requirements, such as requiring the static crushing strength of the honeycomb aluminum monomer to meet a certain numerical range requirement. When the honeycomb aluminum material and aperture diameter are determined, combined with the crushing strength requirement of the honeycomb aluminum monomer, the initial wall thickness d of the honeycomb aluminum unit in the equivalent finite element model can be confirmed by using the honeycomb aluminum static compression strength calculation formula (5):

[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, is the aperture diameter of a single honeycomb aluminum after equivalent conversion. For the honeycomb aluminum monomer structure with a constant static crushing force value requirement in the barrier design technical specification, the wall thickness of the honeycomb aluminum unit is a fixed value. For the honeycomb aluminum monomer structure with a gradually changing static crushing force value in the barrier design technical specification, the honeycomb aluminum unit barrier can also be designed as a gradually changing value.

[0085] For example, for the static mechanical property requirements of MPDB honeycomb aluminum, when 3003 aluminum material is used for the honeycomb aluminum and the pore diameter is set to 30 mm, in combination with the static compressive strength calculation formula (5) of the 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, calculated according to its median crushing strength of 0.3249 MPa, pore diameter of 30 mm and static yield strength of 0.118 Mpa, it can be known that the wall thickness d of honeycomb aluminum monomer 1 is 0.25 mm. Similarly, for honeycomb aluminum monomer 3 under the same pore diameter, its wall thickness d is 0.73 mm. The static crushing force requirement of honeycomb aluminum monomer 2 is a gradually changing value, and the median value gradually changes linearly from 0.686 MPa to 1.02 MPa. Similarly, the wall thickness of honeycomb aluminum monomer 2 can be obtained to gradually change linearly from 0.41 mm to 0.54 mm.

[0086] Next, go to step S130.

[0087] At step S130, differential mesh division is performed based on the single and double layer thicknesses of the hexagonal honeycomb aluminum.

[0088] In the embodiment of the present invention, the differential mesh division based on the single and double layer thicknesses of the hexagonal honeycomb aluminum includes: at the edge of the honeycomb aluminum with two layer thicknesses, three differential meshes with a large middle and small two sides are adopted; wherein, the small mesh size divided in the tearing area at both ends is set to a; at the edge of the honeycomb aluminum with a single layer thickness, three evenly divided meshes are adopted, and the mesh size is ; the mesh size in the middle area is , and the small mesh size is defined; the longitudinal mesh division size of the simulated honeycomb aluminum monomer is determined by the length Z of the actual honeycomb aluminum crushing a single fold.

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

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

[0091] To better conform to the deformation and tearing patterns of the honeycomb aluminum cells, three differentiated meshes with a larger middle and smaller sides are adopted at the edges of the honeycomb aluminum with two layers of thickness. At the edges of the honeycomb aluminum with a single layer of thickness, three evenly divided meshes are adopted. For the mesh size in the longitudinal crushing direction of the honeycomb aluminum, it can be confirmed through the crushing test of a single honeycomb aluminum cell. The longitudinal mesh division size of the simulated single honeycomb aluminum cell is determined according to the length Z of a single fold in the actual honeycomb aluminum crushing, so as to more closely reflect the crushing fold deformation of the honeycomb aluminum. Through steps S110 and S120, the different honeycomb aluminum cells within the entire barrier can be equivalent, and the finite element model of the honeycomb aluminum cell can be established.

[0092] For example, a compression test is carried out on the honeycomb aluminum cell 1 of the MPDB barrier, and the compression deformation is as Figure 9 shown. It can be seen that at the edges of the honeycomb aluminum with two layers of thickness (corresponding to Figure 9 (1) the blue area), the middle area of the honeycomb aluminum after deformation is relatively intact, and the two end areas are torn. Therefore, three differentiated meshes with a larger middle and smaller sides can be adopted. For the small meshes divided in the two end tearing areas, the small mesh size a can be set to include but not limited to 2, 3, 4, 5 mm, and the mesh size of the middle area is . At the edges of the honeycomb aluminum with a single layer of thickness (corresponding to Figure 9 (1) the green area), the deformation and tearing of the honeycomb aluminum are relatively uniform, and three evenly divided meshes can be adopted, that is, the mesh size is . For the mesh size in the longitudinal crushing direction of the honeycomb aluminum, it can be determined according to the deformation of the honeycomb aluminum crushing fold (as Figure 9 (3) shown). For example, if the length Z of a single fold in the test is 5 mm, the mesh size in the crushing direction is set to 5 mm. Through the above method, the equivalent transformation of the finite element model of the honeycomb aluminum cell 1 can be completed. Similarly, the finite element models of the honeycomb aluminum cells 2 and 3 can be established.

[0093] Next, go to step S140.

[0094] At step S140, calculate the failure force of the beam element in the equivalent finite element model based on the axial fracture failure force of the adhesive for the physical honeycomb aluminum colliding with the barrier.

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

[0096] f = PLW / N;

[0097] where 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 elements per unit area; L is the length of the honeycomb aluminum cell structure; W is the width of the honeycomb aluminum cell structure.

[0098] More specifically, honeycomb aluminum barriers usually connect honeycomb aluminum monomers with different structural sizes to the mounting backboard through adhesives. In tests, the adhesives may crack due to excessive stress. To reproduce the phenomenon of adhesive cracking in simulation, it is necessary to confirm the bonding strength of the adhesives through tests. The tensile strength P of the adhesives can be measured by the standard test specification ASTM C297-61. The measurement method is as follows: fabricate a honeycomb aluminum test specimen with length and width dimensions of 100×100 mm and a height of 15 mm, conduct a planar tensile test to determine the fracture force of the adhesive, and divide it by the test area of the honeycomb aluminum to obtain the tensile strength P of the adhesive. In the finite element model of the honeycomb aluminum barrier, beam elements are used to simulate the adhesive connection. A beam element is set at each unit node, and the axial fracture failure force f is input in the simulation keyword of the beam element. This failure force can be obtained by dividing the tensile strength P by the number of beam elements per unit area. The calculation formula is (6):

[0099] f = PLW / N (6)

[0100] For example, honeycomb aluminum monomers are connected to the mounting backboard through adhesives. In tests, the adhesives may crack due to excessive stress. In the simulation model, beam elements are established for simulation, as Figure 10 shown, and its fracture is controlled by setting the failure force parameter of the beam element. The failure force parameter of a single beam element can be obtained in the following way: Prepare a honeycomb aluminum test specimen with length and width dimensions of W×L and a height of 15 mm with reference to the test specification ASTM C297-61. Conduct a planar tensile test on the specimen to determine the fracture force of the adhesive, divide it by the test area of the honeycomb aluminum to obtain the tensile strength P of the adhesive, and divide it by the number of beam elements per unit area N to obtain the fracture failure force of the beam element. Referring to the calculation formula (6), the failure force of the beam element can be set to 2.17 KN. The adhesive materials of honeycomb aluminum monomers 1, 2, and 3 are the same, and the failure force parameters of the beam elements are set the same.

[0101] Next, go to step S150.

[0102] At step S150, based on the pore size, the initial wall thickness, the result of the differential grid division, and the failure force of the beam element, a finite element model of the honeycomb aluminum part in the initial version of the collision barrier is established.

[0103] Next, go to step S160.

[0104] At 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 simulates bolts through fixed connection and is connected to the finite element model of the rigid component.

[0105] More specifically, after determining the modeling method of the honeycomb aluminum monomer and the adhesive, for the back panel connecting the honeycomb aluminum in the barrier, shell elements can be used for simulation, and the thickness and material of the shell elements can be added according to the actual thickness and material of the back panel. By assembling the honeycomb aluminum monomer, the adhesive, and the back panel 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, as shown in Figure 11 .

[0106] Another 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 finite element rigid trolley can be carried out according to the overall dimensions, tire wheelbase, weight, and centroid of the physical trolley. In the finite element software, the bolt connection can be simulated by the way of fixed connection, and the honeycomb aluminum model and the rigid trolley model can be combined to complete the model development of the initial version of the moving honeycomb aluminum barrier. For the barrier 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-degree-of-freedom directions can be constrained to simulate the rigid wall. Similarly, in the finite element software, by the way of fixed connection, the honeycomb aluminum model and the rigid wall model can be combined to complete the model development of the initial version of the fixed honeycomb aluminum barrier.

[0107] For example, after determining the finite element simulation method of the honeycomb aluminum monomer and the adhesive, for the back panel connecting the honeycomb aluminum in the barrier, shell elements can be used for simulation. The average mesh size can be divided according to 20mm. The setting of this size is not the only value, including but not limited to 20mm, 25mm, 30mm, 35mm. In the finite element model, the thickness and material of the shell elements are added according to the actual thickness and material of the back panel. Connecting the established honeycomb aluminum monomer model, adhesive model, and back panel model into one in the finite element analysis software can complete the finite element model of the honeycomb aluminum part in the initial version of the collision barrier, as shown in Figure 11 The honeycomb aluminum finite element model part. Another part of the collision barrier is the honeycomb aluminum structure carrier, which is usually a trolley structure with very high structural strength. The finite element modeling of the trolley structure can be carried out according to the overall dimensions, tire wheelbase, weight, and centroid of the physical trolley. The honeycomb aluminum part and the trolley part are usually bolt-connected, and the simulation is carried out by the way of fixed connection in the finite element software, as shown in Figure 11 the schematic diagram of the trolley finite element model part in. Through the above steps, the model development of the initial version of the moving honeycomb aluminum barrier can be completed.

[0108] In the embodiments of the present invention, the verification of the overall dynamic mechanical properties of the wall barrier includes: fixing the finite element model of the honeycomb aluminum part in the initial version of the collision wall barrier on a rigid wall; a tubular impactor of a specific form impacts the honeycomb aluminum collision wall barrier at a speed of 60 km / h, and the tubular impactor overlaps the surface of the honeycomb aluminum collision wall barrier by 800 mm; performing a collision simulation analysis on the tubular impactor; wherein, within the deformation displacement range of the honeycomb aluminum collision wall barrier, when the overall dynamic simulation force-displacement curve of the honeycomb aluminum collision wall barrier is less than the preset threshold, increase the thickness of the honeycomb aluminum cells within this displacement range; within the deformation displacement range of the honeycomb aluminum collision wall barrier, when the overall simulation force-displacement curve of the honeycomb aluminum collision wall barrier is greater than the preset threshold, reduce the thickness of the honeycomb aluminum cells within this displacement range; iteratively verify the mechanical properties of the initial version of the honeycomb aluminum collision wall barrier until the force-displacement characteristics meet the preset requirements. The finite element model of the collision wall barrier after the iterative verification is as Figure 12 .

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

[0110] For example, for the MPDB wall barrier, the dynamic requirement is: the honeycomb aluminum part of the MPDB wall barrier is fixed on a rigid wall, a tubular impactor of a specific form impacts the wall barrier at a speed of 60 km / h, the tubular impactor overlaps the surface of the wall barrier by 800 mm, and the collision schematic diagram is as Figure 13 shown, and the collision force-displacement curve of the honeycomb aluminum wall barrier should be located within the mechanical channel specified in Figure 14 . Therefore, a collision simulation analysis of the tubular impactor is performed.

[0111] The design method of the finite element model of the honeycomb aluminum barrier proposed by the present invention establishes the finite element model of the honeycomb aluminum barrier through a new method on the basis of ensuring calculation accuracy and calculation efficiency. Specifically, it is embodied in: determining the equivalent conversion method of the honeycomb aluminum structure size, proposing a set of calculation formulas, and equivalently converting the pore diameter and thickness of the honeycomb aluminum on the basis of both calculation accuracy and efficiency. Considering the local deformation and tearing mode of the honeycomb aluminum unit, a grid division scheme with differences in the thickness of the single and double layers of the hexagonal honeycomb aluminum is proposed. 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 initial version of the finite element barrier model is established, 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, reflect the real 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] As described above, the above is only the specific implementation manner 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 those skilled in the art within the technical scope disclosed by the present disclosure should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to 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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