Honeycomb structure compression-shear hybrid loading efficient simulation method considering loading angle

Abstract

The invention discloses a honeycomb structure compression-shear hybrid loading efficient simulation method considering a loading angle, and the method aims at a honeycomb structure, employs an entity equivalent modeling method, ignores the bending, folding and other local details of honeycomb cells, and improves the simulation efficiency of the honeycomb structure compression-shear hybrid loading. Simulation parameters meeting conditions are determined through a simple sample piece test, an overall deformation mode and a stress-strain process consistent with a real test are obtained, modeling is simple, and the calculation efficiency is greatly improved. In an entity equivalent model of the honeycomb structure compression-shear mixed load efficient simulation method, the influence of the compression strength changing along with the loading angle is considered, the influence of the shear action is considered, meanwhile, shear damage factors in all directions are defined, and therefore the method can be suitable for complex working conditions such as front collision, inclined collision at different angles, plane overall collision and local collision.

Description

Technical Field

[0001] This application relates to the technical field of anti-collision energy dissipation structure modeling and simulation analysis, and particularly to an efficient simulation method for the combined compression and shear loading of honeycomb structures considering the loading angle. Background Art

[0002] In collision devices such as ship collisions and vehicle collisions, honeycomb structures have extensive application potential due to their high specific energy absorption ratio and strength. Compared with traditional materials, honeycomb structures can provide higher energy absorption capacity at a relatively light weight, thus playing an important role in collision events. Honeycomb structures belong to periodic array porous structures, and their cell sizes are usually at the millimeter level. When simulating large-scale structures ranging from several meters to dozens of meters, the method of fine modeling of honeycomb structures leads to a sharp increase in the number of finite element model meshes, extremely low computational efficiency, and a large consumption of computational resources and time. In addition, in actual collision events, honeycomb structures may be impacted from different angles and affected by the irregular configuration of the impact object, resulting in honeycomb structures being subjected to multiple forces such as compression and shear simultaneously.

[0003] Liu Ming, Fei Jing, Fan Tiqiang, etc. from China Automotive Engineering Research Institute Co., Ltd. proposed a patent "An Equivalent Method for a Honeycomb Model of a Side Collision Barrier", which includes the following content: According to the honeycomb model size and the initial cell side length, match the equivalent cell side length after cell expansion; According to the cell expansion theory, obtain the theoretical wall thickness of the equivalent cell from the initial cell wall thickness: Simulate the equivalent cell, and perform equivalent analysis based on the mechanical properties of the honeycomb model before cell expansion to obtain the scaled wall thickness of the equivalent cell: Obtain the scaling coefficient based on the initial cell wall thickness and the scaled wall thickness of the equivalent cell: Set several coefficients and substitute them into the scaled wall thickness, and through the wall barrier impact wall test, compare the closeness of the collision test data before and after cell expansion under different coefficients to obtain the correction coefficient: According to the scaling coefficient and the correction coefficient, obtain the corrected wall thickness of the equivalent cell from the initial cell wall thickness, but there are the following problems: (1) When the multiple of equivalent cell expansion is large, there are significant differences in the deformation behavior of the honeycomb structure before and after cell expansion; (2) This simulation method does not consider the influence of the loading angle on cell expansion, and at the same time cannot consider the influence of the combined compression and shear action; (3) In the simulation, every time the side length / wall thickness of the honeycomb is changed, it is necessary to recalibrate the cell expansion theory again, and there are certain difficulties in simulation modeling.

[0004] Therefore, the research on the equivalent simulation method of honeycomb structures under large-scale collision conditions has become an important topic in the current engineering field. By developing an efficient and accurate simulation method, the performance of honeycomb structures in collision events can be effectively evaluated, providing more reliable technical support for the design and optimization of collision devices. Summary of the Invention

[0005] An embodiment of the present application provides an efficient simulation method for the combined compression and shear loading of a honeycomb structure considering the loading angle, aiming to simplify the modeling difficulty, improve the calculation efficiency, and reduce the calculation cost.

[0006] To achieve the above object, the present application provides an efficient simulation method for the combined compression and shear loading of a honeycomb structure considering the loading angle, including the following steps: S1. Solid equivalent modeling: Based on the simulation, the periodic array of porous thin-walled honeycomb structures is globally equivalent to a solid block; S2. Define the plastic compression behavior of the honeycomb structure: Conduct compression tests on three honeycomb specimens in the X, Y, and Z axes respectively to obtain the stress-strain curves in the corresponding directions; S3. In the main loading direction of the honeycomb structure, conduct tests on the honeycomb specimens with different loading angles and compressive strengths to obtain the compressive strength-angle relationship curve; S4. Define the plastic shear behavior of the honeycomb structure: Conduct shear tests on three honeycomb specimens in the XY, YZ, and XZ planes respectively to obtain the shear stress-strain curves in the corresponding planes. For the softening section in each plane's shear stress-strain curve, convert it into a damage coefficient; S5. Calculate and obtain the shear strength values in each direction of the honeycomb structure and the hydrostatic strength value of the honeycomb to ensure that the equivalent solid block can remain stable when subjected to stresses in different directions.

[0007] Optionally, in step S2, compression tests are conducted on three honeycomb specimens in the X, Y, and Z axes respectively, and the force-displacement curves of the corresponding direction compressions are measured. Through force / area and displacement / total length, they are converted into the stress-strain curves in the corresponding directions.

[0008] Optionally, in step S3, the main loading direction is the force-bearing direction when the honeycomb structure is actually used for collision.

[0009] Optionally, the main loading direction is the axis of the cell in the honeycomb structure.

[0010] Optionally, in step S4, the shear stress-strain curve of the honeycomb structure is similar to a parabola. The shear stress increases monotonically with the strain, and rapidly drops after reaching the maximum value. The entire dropping process is called the softening section, and the softening section is characterized by a damage coefficient curve with the shear strain as the abscissa.

[0011] Optionally, the efficient simulation method for the combined compression and shear loading of the honeycomb structure is applicable to aluminum honeycomb structures and steel honeycomb structures.

[0012] Optionally, the efficient simulation method for the combined compression and shear loading of the honeycomb structure is applicable to anisotropic non-linear materials.

[0013] The beneficial effects of the efficient simulation method for the honeycomb structure under combined compression and shear loads considering the loading angle provided by this application are as follows: Compared with the prior art, the efficient simulation method for the honeycomb structure under combined compression and shear loads in this application uses a solid equivalent modeling method for the honeycomb structure, without modeling the cells of the honeycomb. Based on simulation, it is equivalently regarded as a solid block as a whole, ignoring local details such as the bending and folding of honeycomb cells, determining the simulation parameters that meet the conditions through simple specimen tests, and obtaining the overall deformation mode and stress-strain history consistent with the actual test. The modeling is simple and the calculation efficiency is greatly improved.

[0014] In the solid equivalent model of the efficient simulation method for the honeycomb structure under combined compression and shear loads, the influence of the change in compressive strength with the loading angle is considered, and it can be applied to the plastic large deformation conditions of collisions at different impact angles. The influence of the shear effect is considered, and the shear damage factor in each direction is defined, which can simulate the complex loading mode during the impact process. Therefore, it can be applied to complex working conditions such as frontal collision, oblique collision at different angles, plane integral collision, and local collision. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0016] Among them: Figure 1 is a three-dimensional schematic diagram of the honeycomb structure; Figure 2 is the shear stress-strain curve diagram of the honeycomb structure; Figure 3 is the compression test diagram of the honeycomb specimen along the Z-axis in the efficient simulation method for the honeycomb structure under combined compression and shear loads shown in an embodiment of this application; Figure 4 is the oblique compression test diagram of the honeycomb specimen in the main loading direction in the efficient simulation method for the honeycomb structure under combined compression and shear loads shown in an embodiment of this application; Figure 5 is the shear test diagram of the honeycomb specimen in the XY plane in the efficient simulation method for the honeycomb structure under combined compression and shear loads shown in an embodiment of this application; Figure 6 is the test diagram of the honeycomb specimen compressed with an arc-shaped indenter along the Z-axis in the efficient simulation method for the honeycomb structure under combined compression and shear loads shown in an embodiment of this application; Figure 7 is the schematic comparison diagram of the arc surface compression test and the simulation of the efficient simulation method for the honeycomb structure under combined compression and shear loads of this application; Figure 8 It is the equivalent method verification and calculation efficiency diagram of the high-efficiency simulation method for the combined compression and shear loading of the honeycomb structure shown in an embodiment of the present application. Among them, Figure 8 (a) is the stress-strain curve diagram of the honeycomb structure under the compression of a flat hammer head in the experiment, solid equivalent modeling, and shell element refined modeling, and the calculation time bar chart under the solid equivalent modeling and shell element refined modeling; Figure 8 (b) is the stress-strain curve diagram of the honeycomb structure under the compression of an arc-shaped hammer head in the experiment, solid equivalent modeling, and shell element refined modeling, and the calculation time bar chart under the solid equivalent modeling and shell element refined modeling; Figure 9 It is the overall technical roadmap of the high-efficiency simulation method for the combined compression and shear loading of the honeycomb structure shown in an embodiment of the present application; Figure 10 It is the comparison diagram of the impact force-displacement curve in the comparative experiment and simulation of the series honeycomb under the arc-shaped indenter shown in an embodiment of the present application; Figure 11 It is the comparison diagram of the deformation mode in the comparative experiment and simulation of the series honeycomb under the arc-shaped indenter shown in an embodiment of the present application; Figure 12 It is the structural deformation mode diagram in the drop hammer test and simulation of the composite structure shown in an embodiment of the present application. Among them, Figure 12 (a) is the test device diagram; Figure 12 (b) is the structural deformation mode diagram in the simulation; Figure 12 (c) is the structural deformation mode diagram in the experiment; Figure 13 It is the schematic diagram of the impact force-time curve and the hammer head displacement-time curve obtained from the experiment and simulation shown in an embodiment of the present application.

[0017] Main element symbol description: 1. Honeycomb sample; 2. Flat hammer head; 3. Support steel plate; 4. Left steel plate; 5. Right steel plate; 6. Arc-shaped hammer head. Detailed implementation manners

[0018] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure content of the present application more thorough and comprehensive.

[0019] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0020] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0022] An embodiment of the present application provides an efficient simulation method for the combined compression and shear loading of a honeycomb structure considering the loading angle, including the following steps: S1. Solid equivalent modeling: Based on simulation, the entire honeycomb structure is equivalently modeled as a solid block; S2. Define the plastic compression behavior of the honeycomb structure: Conduct compression tests on three honeycomb specimens in the X, Y, and Z axial directions respectively to obtain the stress-strain curves in the corresponding directions; S3. In the main loading direction of the honeycomb structure, conduct tests between different loading angles and compressive strengths on the honeycomb specimens to obtain the compressive strength-angle relationship curve; S4. Define the plastic shear behavior of the honeycomb structure: Conduct shear tests on three honeycomb specimens in the XY, YZ, and XZ planes respectively to obtain the shear stress-strain curves in the corresponding planes. For the softening section in the shear stress-strain curve of each plane, convert it into a damage coefficient; S5. Calculate and obtain the shear strength values in each direction of the honeycomb structure and the hydrostatic strength value of the honeycomb to ensure that the equivalent solid block can remain stable when subjected to stresses in different directions.

[0023] Among them, in step S2, compression tests are conducted on three honeycomb specimens in the X, Y, and Z axial directions respectively, and the force-displacement curves of the corresponding direction compressions are measured. Through force / area and displacement / total length, they are converted into the stress-strain curves in the corresponding directions.

[0024] In the embodiment of the present application, the efficient simulation method for the honeycomb structure under combined compression and shear loading targets the honeycomb structure and adopts the solid equivalent modeling method. There is no need to model the cells of the honeycomb. Based on simulation, it is globally equivalent to a solid block, ignoring local details such as the bending and folding of honeycomb cells. By means of simple specimen tests, the simulation parameters that meet the conditions are determined, and the overall deformation mode and stress-strain history consistent with the real test are obtained. The modeling is simple, and the calculation efficiency is greatly improved.

[0025] In the solid equivalent model of the efficient simulation method for the honeycomb structure under combined compression and shear loading, the influence of the change of compressive strength with the loading angle is considered, and it can be applied to the plastic large deformation conditions of collisions at different impact angles. The influence of shear action is considered, and at the same time, the shear damage factors in all directions are defined, and the complex loading modes during the impact process can be simulated. Therefore, it can be applied to complex conditions such as frontal collision, oblique collision at different angles, overall plane collision, and local collision, and the influence of loading angle and combined compression and shear loading can be considered, with better applicability.

[0026] The solid equivalent modeling method of the present application is not only applicable to aluminum honeycombs, but also to honeycomb structures of other alloy materials (such as steel honeycombs); it is also applicable to other anisotropic non-linear materials, such as aluminum foam, polyurethane foam materials, etc.

[0027] Comparison with existing honeycomb equivalent patents: First of all, it should be clear that the most basic and mature honeycomb simulation method at present is to use shell element fine modeling, that is, in the finite element software, the real honeycomb geometric configuration is replicated 1:1. This method has good calculation accuracy, but the calculation efficiency is low in large-size models. The comparison between some currently published / authorized patents and the present invention is as follows: 1) A method and system for determining the failure mechanical parameters of honeycomb aluminum materials Difference: This patent focuses on the failure parameters of the honeycomb base material (aluminum alloy) and the failure simulation method of aluminum honeycombs. The finite element model used is a 1:1 honeycomb geometric configuration of shell elements, and does not involve the concept of "equivalence". In other words, the focus of this patent is on how to simulate accurately, while the focus of the efficient simulation method for the honeycomb structure under combined compression and shear loading in the present application is on how to equivalent the honeycomb structure; 2) An equivalent method for a honeycomb model of a side collision barrier Differences: This patent performs cell expansion equivalence on the honeycomb (for example, equivalent the honeycomb with a side length of 10 mm to a honeycomb with a side length of 100 mm, and at the same time adjust other parameters to make the mechanical properties before and after equivalence approximate). When performing finite element modeling, shell elements are still used, while the efficient simulation method for the honeycomb structure under combined compression and shear loads in this application uses solid elements, which is essentially different in principle. In addition, different loading conditions have an impact on cell expansion equivalence (for example, there are differences in the cell expansion formulas for uniaxial loading and oblique loading). Therefore, it is difficult to use a set of formulas for cell expansion for complex loads, while this application can simulate complex loads; 3) A honeycomb equivalent unit and a parameter calculation method based on the honeycomb equivalent unit This patent proposes an equivalent calculation method for honeycomb sandwich panels. Regarding the upper panel, lower panel, and honeycomb as a whole, key parameters such as torsional stiffness and bending stiffness are obtained. At the same time, a very small "Y" unit in the honeycomb is equivalently analyzed using the energy method. The method for obtaining simulation parameters in this solution is not clear and systematic; the honeycomb can be regarded as an array of a very large number of "Y" units, but under complex loads, the deformation modes of "Y" units at different positions are different and coupled with each other, making it difficult to obtain a universal force-displacement relationship using the energy method. This patent is applicable to working conditions with simple forces (such as uniaxial compression and overall bending), and it is difficult to simulate local loads and combined compression and shear loads.

[0028] Differences: The object of equivalence in the efficient simulation method for the honeycomb structure under combined compression and shear loads in this application is the honeycomb structure, while the object of equivalence in this patent is the panel + honeycomb in the sandwich structure; the specific equivalent implementation methods are different, especially the methods for plastic behavior are different. This patent uses the energy method to obtain the force-displacement relationship to describe plastic behavior, while this application obtains the stress-strain relationship based on triaxial compression tests and triaxial shear tests; the scope of equivalence is different. This application considers the loading angle, shear action, and shear damage accumulation, while this patent does not. The energy method proposed in this patent is only applicable to working conditions with simple forces, while the efficient simulation method for the honeycomb structure under combined compression and shear loads in this application is applicable to more complex forces; the method for obtaining the force-displacement in this patent requires iteration, that is, a large amount of trial and error and debugging are needed, which is actually a kind of fitting, while the equivalent simulation parameters in this application are obtained through experiments and calculations, reflecting the mechanical essence of the structure.

[0029] In short, compared with some existing patents, the significant unique features of the efficient simulation method for the honeycomb structure under combined compression and shear loads in this application are: different equivalence principles and methods, and different scopes of application.

[0030] This application focuses on the metal honeycomb structure and simulates its plastic behavior under oblique loading and combined compression-shear loading. The overall mechanical properties are characterized through solid equivalent simulation, while local details such as the bending and folding of honeycomb cells are ignored. This application lies in how to determine the solid equivalent simulation parameters under combined compression-shear loading based on a series of sample tests, obtain accurate overall deformation modes and stress-strain histories, and significantly improve the computational efficiency. The specific implementation methods are as follows: 1) Define the plastic compression behavior of the honeycomb structure The honeycomb structure is a two-dimensional periodic regular hexagonal structure, as Figure 1 shown. The key parameters affecting the honeycomb strength are the side length of the regular hexagon, wall thickness, and material; It should be noted that the equivalent simulation method proposed in the embodiments of this application is a general method for honeycomb structures and honeycomb-like structures, not for a specific honeycomb. For honeycombs of any size, dimensions, and materials, the method proposed in this application can be used for equivalence. For easy understanding, a case is provided. The honeycomb structure parameters are: side length 4 mm, wall thickness 0.08 mm, and material aluminum alloy AL5052; First, axial compression tests need to be carried out on the honeycomb structure in three directions respectively. The force-displacement curves of compression in the corresponding directions can be measured in the tests. By converting force / area and displacement / total length into stress-strain curves, the stress can be updated in real time according to the strain state of the structure during simulation calculation, thus defining the three-way plastic compression behavior of the honeycomb; On this basis, tests between different loading angles and compression strengths are carried out in the main loading direction to obtain a strength-angle relationship curve; The test method for the flat pressure mechanical properties is as Figure 3 shown, and the test methods for the performance at different loading angles are as Figure 4 shown.

[0031] 2) Define the plastic shear behavior of the honeycomb Three-plane shear tests are carried out on the honeycomb structure (as Figure 5 shown) to obtain the shear stress-strain curves of the corresponding planes. The shape of the shear stress-strain curve of the honeycomb structure is parabolic, the stress increases monotonically with the strain, and drops rapidly after reaching the maximum value. The dropping section of the curve represents the occurrence of shear damage in the honeycomb structure, indicating that part of the honeycomb structure is torn and cut. The entire dropping process is called the "softening section", as Figure 2 shown; The softening section is characterized by a curve with shear strain as the abscissa and damage coefficient between 0 and 1 as the ordinate.

[0032] 3) Anti-distortion of elements under combined compression-shear loading To prevent the equivalent unit from undergoing element distortion under small stresses, the shear strength in all directions and the hydrostatic strength of the honeycomb structure are further input. The shear strength is obtained through the above-mentioned 2) shear test, and the hydrostatic strength is obtained through the hydrostatic strength test. Ensure that the equivalent unit can remain stable when subjected to stresses in different directions; Figure 7 A comparative analysis of the effect of element anti-distortion treatment is given. It can be found that the traditional shell element fine modeling is consistent with the experimental deformation mode. Without dealing with element distortion, the structural deformation mode is distorted, showing excessive stretching of local elements and macroscopic non-real lateral deformation. After dealing with element distortion, the simulation results of the solid equivalent model are consistent with the experimental results and the results of the traditional shell element fine model.

[0033] 4) Verification of the equivalent method To verify the calculation accuracy, it can be compared with the plane compression test ( Figure 3 ) and the combined compression-shear test ( Figure 6 ). Figure 8 To verify the results, it shows that the efficient simulation method for the combined compression-shear loading of the honeycomb structure in this application has high accuracy and greatly improves the calculation efficiency.

[0034] The specific application process is as follows: 1. As Figure 9 shown, the overall technical route of the efficient simulation method for the combined compression-shear loading of the honeycomb structure is shown.

[0035] 2. Specific process 1) Constitutive type ① Type one: mainly used for honeycombs and foams with actual anisotropic behavior. For all normal stresses and shear stresses, the nonlinear elastoplastic material behavior can be defined separately, which is completely decoupled; ② Type two: usually used for aluminum crushable foam materials with anisotropic behavior, and there are three yield surfaces available. The first yield surface defines the nonlinear elastoplastic material behavior of all normal stresses and shear stresses respectively, which is completely decoupled. The second yield surface takes into account the influence of the deviatoric load, and it is isotropic. However, due to this definition of the second yield surface, the material may collapse in shear mode due to low shear impedance, and there is no obvious way to increase the shear resistance without changing the pure uniaxial compression behavior. Therefore, for the third yield surface, the model is modified to specify the shear resistance and hydrostatic resistance of the material without affecting the uniaxial performance.

[0036] 2) Element type For solid honeycomb elements, the main element types are fully integrated elements and nonlinear spring elements, and the nonlinear spring elements are only applicable to constitutive type two.

[0037] 3) Working condition verification analysis Considering the mechanical behavior of the honeycomb under combined compression and shear, two types of working conditions were designed: plane compression (uniaxial compression behavior) and arc surface compression (combined compression and shear behavior). According to the available constitutive types and element types, the available combinations of the honeycomb model are as follows: ① Constitutive type I + fully integrated element; ② Constitutive type II (second and third yield surfaces not activated) + fully integrated element; ③ Constitutive type II (second and third yield surfaces activated) + fully integrated element; ④ Constitutive type II (second and third yield surfaces not activated) + non - linear spring element; ⑤ Constitutive type II (second and third yield surfaces activated) + non - linear spring element.

[0038] 4) Constitutive + element type selection Based on the working condition analysis results in 3), it can be obtained that: Constitutive type I + fully integrated element - can better reflect the deformation mode during flat compression, with a slight increase in the impact force before densification (unreasonable), and unreasonable lateral distortion under arc surface action; Constitutive type II with second and third yield surfaces activated + fully integrated element - can better reflect the deformation mode and impact force curve during both flat compression and arc surface compression; Constitutive type II with second and third yield surfaces not activated + non - linear spring element - can better reflect the deformation mode during flat compression, with a slight increase in the impact force before densification (unreasonable), and unreasonable lateral distortion under arc surface action; Constitutive type II with second and third yield surfaces activated + non - linear spring element - can better reflect the deformation mode and impact force curve during flat compression, but there is unreasonable lateral distortion under arc surface action; Therefore, constitutive type II with second and third yield surfaces activated + fully integrated element has better applicability.

[0039] 5) Constitutive parameters Calculate the parameters of constitutive type II according to the above test results, such as the function between yield stress and loading angle, the function between hardening stress and volumetric strain, shear strain damage function, shear strength and hydrostatic strength, etc.

[0040] 6) Experimental verification ① Comparison of series honeycomb arc - shaped indenter tests The impact force curve is as Figures 10 - 11As shown. Taking G1 as an example, the deformation processes in the experiment and simulation are compared. Solid elements are used to simulate the honeycomb in the simulation, and the strain nephogram is drawn to more intuitively reflect the deformation area. Comparing the experimental curve and the simulation curve, whether it is the rising section or the plateau section, they have a high degree of coincidence. It shows that the simulation constitutive model and the simulation method have good simulation accuracy; ② Comparison of drop hammer tests on composite structures Figure 12 The structural deformation modes in the experiment and simulation are given, and the typical deformation positions are extracted for comparison.

[0041] Figure 13 The impact force-time curve and the hammer head displacement-time curve obtained from the experiment and simulation are compared. At the initial stage of the impact, an initial peak appears in the curve. Since the hammer head has an arc-shaped configuration, the contact area with the specimen increases continuously during the impact, so the impact force increases accordingly and gradually reaches the maximum peak. Finally, due to the decrease in the speed of the specimen, the hammer head rebounds and unloads rapidly. The comparison results show that whether it is the impact force or the hammer head displacement curve, the trends in the experiment and simulation are highly coincident. Among them, the error of the maximum peak impact force is 6.4%, the error of the impact response time (up to the start time of unloading) is 7%, and the error of the maximum displacement of the hammer head is 3%. Generally speaking, the errors of the key indicators such as the impact force and the hammer head displacement in the simulation and the experiment are all less than 8%, indicating that the simulation method has high accuracy.

[0042] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0043] The above embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as a limitation to the scope of the application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. An efficient simulation method for the combined compression and shear loading of a honeycomb structure considering the loading angle, characterized in that, It includes the following steps: S1. Solid equivalent modeling: Based on simulation, the periodic array of porous thin-walled honeycomb structures is globally equivalent to a solid block. S2. Define the plastic compression behavior of the honeycomb structure: Conduct compression tests on three honeycomb specimens in the X, Y, and Z axes respectively to obtain the stress-strain curves in the corresponding directions. S3. In the main loading direction of the honeycomb structure, conduct tests between different loading angles and compression strengths on the honeycomb specimens to obtain the compression strength-angle relationship curve. S4. Define the plastic shear behavior of the honeycomb structure: Conduct shear tests on three honeycomb specimens in the XY, YZ, and XZ planes respectively to obtain the shear stress-strain curves in the corresponding planes. For the softening section in the shear stress-strain curve of each plane, convert it into a damage coefficient. S5. Calculate and obtain the shear strength values in each direction and the hydrostatic strength value of the honeycomb structure to ensure that the equivalent solid block can remain stable when subjected to stresses in different directions.

2. The efficient simulation method for combined compression and shear loading of a honeycomb structure considering the loading angle according to claim 1, characterized in that In step S2, conduct compression tests on three honeycomb specimens in the X, Y, and Z axes respectively, measure the force-displacement curves of compression in the corresponding directions, and convert them into stress-strain curves in the corresponding directions through force / area and displacement / total length.

3. The high-efficiency simulation method for combined compression and shear loading of a honeycomb structure considering the loading angle according to claim 1, wherein In step S3, the main loading direction is the stress direction when the honeycomb structure is actually used for collision.

4. The efficient simulation method for the honeycomb structure under combined compression and shear loads considering the loading angle according to claim 3, wherein The main loading direction is the axial direction of the cell in the honeycomb structure.

5. The efficient simulation method for combined compression and shear loading of a honeycomb structure considering the loading angle according to claim 1, characterized in that In step S4, the shape of the shear stress-strain curve of the honeycomb structure is similar to a parabola. The shear stress increases monotonically with strain, rapidly drops after reaching the maximum value, and the entire dropping process is called the softening section. The softening section is characterized by a damage coefficient curve with the abscissa being the shear strain.

6. The high-efficiency simulation method for the combined compression-shear loading of the honeycomb structure considering the loading angle according to claim 1, characterized in that The efficient simulation method for the combined compression and shear loading of the honeycomb structure is applicable to aluminum honeycomb structures and steel honeycomb structures.

7. The high-efficiency simulation method for combined compression and shear loading of a honeycomb structure considering the loading angle according to claim 1, characterized in that The efficient simulation method for the combined compression and shear loading of the honeycomb structure is applicable to anisotropic nonlinear materials.

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