Gradient lattice structure compression simulation method and system based on hierarchical finite element simulation

Abstract

The application discloses a gradient lattice structure compression simulation method and system based on layered finite element simulation, and relates to the field of finite element simulation.The technical scheme is as follows: a finite element model is established, and simulation data is collected; a load-displacement curve is constructed according to displacement data and load data; layer densification displacement is calculated according to layer densification strain, and the part of the load-displacement curve before the layer densification displacement is intercepted as an effective curve; the effective curve is synthesized to obtain load data and displacement data of the gradient lattice structure; a stress-strain curve is constructed according to the load data and the displacement data of the gradient lattice structure; a stress value is determined according to a preset strain value and a matching strain layer, and the stress value is converted into a load to call a stress-strain cloud atlas, and a total stress-strain cloud atlas is obtained by pasting stress-strain cloud atlases of all layers.The application can solve the problems of large calculation amount, high time cost and difficulty in convergence in finite element simulation of the gradient lattice structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of finite element simulation, more particularly, it relates to a gradient lattice structure compression simulation method and system based on hierarchical finite element simulation. BACKGROUND

[0002] Finite element simulation has unique advantages in analyzing and predicting the compression performance of gradient lattice structures. The analysis results not only enable engineers to intuitively understand the stress-strain curve, stress and strain distribution, and deformation of the structure during compression, but also reduce the waste of material and human resources caused by manufacturing samples.

[0003] However, since the gradient lattice structure will start to crush from the layer with the smallest volume fraction, while the remaining layers remain relatively stable, until the layer is crushed to densification, the next layer will crush, and the struts of the crushed layer will contact a large number of contacts during this period, greatly increasing the computational load. After complete crushing, these deformed struts in contact will further contact the struts of the next layer, while the struts of the next layer also contact each other, following this rule, the simulation computation load soars, the simulation time cost increases greatly, and the result is also difficult to converge.

[0004] Therefore, how to research and design a gradient lattice structure compression simulation method and system based on hierarchical finite element simulation that can overcome the above defects is a problem we need to solve urgently. SUMMARY

[0005] To solve the problems in the prior art, the purpose of the present application is to provide a gradient lattice structure compression simulation method and system based on hierarchical finite element simulation, which can effectively solve the problems of large computational load, high time cost and difficulty in convergence of finite element simulation of gradient lattice structures, and make the finite element simulation of gradient lattice structures more widely used.

[0006] The above technical purposes of the present application are achieved by the following technical solutions:

[0007] In a first aspect, a gradient lattice structure compression simulation method based on hierarchical finite element simulation is provided, comprising the following steps:

[0008] An independent finite element model is established for each layer in the gradient lattice structure, and the same boundary conditions and displacement are applied to each finite element model to obtain simulation data for the corresponding layer;

[0009] A load-displacement curve is constructed according to the displacement data and load data in the simulation data of each layer;

[0010] The densification displacement of the layer is calculated according to the densification strain of the layer, and the part of the load-displacement curve before the densification displacement is intercepted as an effective curve;

[0011] The load data and displacement data of the gradient lattice structure are obtained by synthesizing the effective curves of each layer;

[0012] The stress-strain curve is constructed according to the load data and displacement data of the gradient lattice structure;

[0013] The strain layer is matched from the stress-strain curve according to the preset strain value, and the corresponding stress value is determined, and after the stress value is converted into load, the corresponding stress-strain nephogram is called from the simulation data of each layer, and the stress-strain nephogram of each layer is pasted to obtain the total stress-strain nephogram representing the deformation of the gradient lattice structure under the preset strain value.

[0014] Further, the boundary conditions and displacement of the finite element model are specifically:

[0015] A compression direction displacement load is applied at the top section;

[0016] The displacement in all directions is limited on the local section at the center of the bottom section;

[0017] And the displacement in the compression direction is limited on the remaining surface of the bottom section.

[0018] Further, the simulation data includes deformation data, stress and strain distribution state data, top section displacement data and load data.

[0019] Further, the construction process of the load-displacement curve is specifically:

[0020] The obtained displacement and load data are listed in the load-displacement graph;

[0021] All data points are smoothly connected to obtain the load-displacement curve of the corresponding layer.

[0022] Further, the effective curve intercepting process is specifically:

[0023] The densification strain of the layer is found out, and then multiplied by the height of the compression direction of the layer to obtain the densification displacement of the layer;

[0024] The densification strain of the layer is regarded as equivalent to the densification strain of the gradient lattice structure.

[0025] Further, the load data and displacement data of the gradient lattice structure are obtained as follows:

[0026] Suppose the a-th layer, take appropriate increments, start to superimpose from the first time the displacement reaches the densification load of the previous layer, and record the load corresponding to the displacement, until the displacement reaches the densification displacement again;

[0027] The displacement of the first time reaching the load is found according to the recorded load-displacement diagram of the un-crushed n-a layer, the obtained n-a+1 displacement values are added to the value of a-1 multiplied by the layer densification displacement, and the sum is taken as the displacement of the gradient lattice structure and the load as the gradient lattice structure load;

[0028] The step is repeated until the nth layer, n is the number of layers of the gradient lattice structure, and 1≤a≤n.

[0029] Further, the construction process of the stress-strain curve is specifically:

[0030] The displacement of the gradient lattice structure is divided by the height of the gradient lattice structure in the compression direction as the strain of the gradient lattice structure;

[0031] The load of the gradient lattice structure is divided by the apparent cross-sectional area perpendicular to the compression direction as the stress of the gradient lattice structure;

[0032] All data are listed in the stress-strain diagram, and the simulation stress-strain curve is obtained after smoothing connection.

[0033] In the second aspect, a gradient lattice structure compression simulation system based on hierarchical finite element simulation is provided, comprising:

[0034] A hierarchical simulation module is configured to establish an independent finite element model for each layer of the gradient lattice structure, apply the same boundary conditions and displacement to each finite element model, and collect simulation data of the corresponding layer;

[0035] A first curve module is configured to construct a corresponding load-displacement curve according to the displacement data and load data in the simulation data of each layer;

[0036] A curve intercepting module is configured to calculate the layer densification displacement according to the layer densification strain, and intercept the load-displacement curve part before the layer densification displacement as an effective curve;

[0037] A curve synthesizing module is configured to synthesize the effective curves of each layer to obtain the load data and displacement data of the gradient lattice structure;

[0038] A second curve module is configured to construct a stress-strain curve according to the load data and displacement data of the gradient lattice structure;

[0039] A superposition simulation module is configured to match the strain layer and determine the corresponding stress value from the stress-strain curve according to a preset strain value, convert the stress value to load, and then retrieve the corresponding stress-strain cloud diagram from the simulation data of each layer, and obtain the total stress-strain cloud diagram representing the deformation of the gradient lattice structure under the preset strain value by pasting the stress-strain cloud diagrams of each layer.

[0040] In a third aspect, a computer terminal is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the gradient lattice structure compression simulation method based on hierarchical finite element simulation according to any one of the first aspect when executing the program.

[0041] In a fourth aspect, a computer readable medium is provided, having a computer program stored thereon, wherein the computer program is executable by a processor to implement the gradient lattice structure compression simulation method based on hierarchical finite element simulation according to any one of the first aspect.

[0042] Compared with the prior art, the present application has the following beneficial effects:

[0043] The gradient lattice structure compression simulation method based on hierarchical finite element simulation provided by the present application can regard each layer as a solid material after compression to densification, and can regard each layer as an insulator for analysis during compression, so as to propose hierarchical gradient simulation; when it is necessary to query the simulation situation under a certain strain value, it is only necessary to convert the stress value into a load, to retrieve the corresponding stress-strain cloud diagram from the simulation data of each layer, and to paste the stress-strain cloud diagrams of each layer to obtain the total stress-strain cloud diagram representing the deformation of the gradient lattice structure under the preset strain value, without the need to perform comprehensive simulation processing from beginning to end, so that the simulation result is efficient and easy to converge, and the problems of large calculation amount, high time cost and difficulty in convergence in the finite element simulation of the gradient lattice structure can be effectively solved, so that the finite element simulation of the gradient lattice structure can be more widely applied. BRIEF DESCRIPTION OF DRAWINGS

[0044] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present application and constitute a part of the application, do not limit the embodiments of the present application. In the drawings:

[0045] Figure 1 is a schematic diagram of a hierarchical model of a gradient lattice structure in an embodiment of the present application;

[0046] Figure 2 is a schematic diagram of boundary conditions and displacement of finite element simulation of a hierarchical model in an embodiment of the present application;

[0047] Figure 3 is a schematic diagram of a load-displacement curve obtained by finite element simulation of a hierarchical model in an embodiment of the present application;

[0048] Figure 4 is a schematic diagram of a stress-strain curve of finite element simulation of a gradient lattice structure in an embodiment of the present application;

[0049] Figure 5 is a total stress-strain cloud diagram of a gradient lattice structure when the strain is 0.4 in an embodiment of the present application;

[0050] Figure 6 is a system block diagram in the embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application in combination with embodiments and drawings, the illustrative embodiments of the present application and the description thereof are only used to explain the present application, and do not limit the present application.

[0052] Embodiment 1: Gradient lattice structure compression simulation method based on hierarchical finite element simulation, which is specifically realized by the following steps.

[0053] Step 1: As shown in Figure 1 , the gradient lattice structure is divided into 4 layers according to the unit cell. As shown in Figure 2 , then a-z direction displacement load is applied at the top section, and xyz three direction displacements are applied at the center of the bottom section, and the rest of the bottom section is limited to z direction displacement. After the simulation simulation, the following data is collected: deformation data, stress and strain distribution state data, top section displacement data and load data. Each layer is collected to obtain simulation data corresponding to each layer.

[0054] Step 2: As shown in Figure 3 , the load data and displacement data are listed on the load-displacement graph, and the smooth connection is obtained to obtain the load curve of 4 layers.

[0055] Step 3: According to the database, the densification strain of the gradient lattice structure is 0.56, which is regarded as the layer densification strain, and multiplied by the layer height 10mm to obtain the layer densification displacement 5.6mm. The part before 5.6mm of each curve is regarded as the effective part, and the lattice structure after 5.6mm is regarded as solid, and the curve is regarded as invalid part.

[0056] Step 4: As shown in Figure 3As shown in the figure, referring to the first layer load-displacement curve, starting from 0, set the increment to be about 0.1 mm, start to superimpose until the layer densification displacement, obtain a series of displacement values, corresponding to the load-displacement curve to obtain the corresponding load value, find the displacement of the first time to reach the load on the load-displacement graph of the second, third and fourth layers which have not been crushed, such as when the displacement is 2 mm, the load of the first layer is 2.89 KN, the displacement of the second layer to reach 2.89 KN for the first time is 0.064 mm, the third layer is 0.019 mm, and the fourth layer is 0.019 mm. The sum of the displacements of the four layers, 2.102 mm, is the displacement of the gradient dot matrix structure, and the load 2.89 KN is the load of the gradient dot matrix structure. Referring to the second layer load-displacement curve, the load at the first layer densification displacement is 2.86 KN, and the displacement of the second layer to reach 2.86 KN for the first time is 0.064 mm. Starting from this displacement, similarly superimpose with an increment of 0.1 mm until the layer densification displacement, similarly obtain a series of displacement values and corresponding loads. Find the displacement of the first time to reach these loads on the load-displacement graph of the third and fourth layers, sum the sum of the displacements of the second, third and fourth layers with the first layer densification displacement 5.6 mm to obtain the displacement of the gradient dot matrix structure. Continue to obtain the displacement and load of the gradient dot matrix structure when the third and fourth layers.

[0057] Step 5: Divide the gradient dot matrix structure displacement by the gradient dot matrix structure compression direction height 10 mm to obtain the gradient dot matrix structure strain. Divide the gradient dot matrix structure load by the apparent cross-sectional area perpendicular to the compression direction 40 mm x 40 mm to obtain the gradient dot matrix structure stress. List all the data in the stress-strain graph, and after smoothing connection, obtain the simulation stress-strain graph as shown in Figure 4 .

[0058] Step 6: As shown in Figure 5 , assuming that you want to understand the stress distribution state and deformation when the gradient dot matrix structure strain is 0.4, first find the strain 0.4 on the third layer on the stress-strain graph, determine the stress value to be 14.26 MPa, convert to load 22.82 KN, corresponding to the third layer displacement 3.74 mm, corresponding to the fourth layer displacement 0.154 mm to reach the load for the first time, then find the stress-strain cloud diagram corresponding to the two displacements and the stress-strain cloud diagram when the first and second layer displacement is 5.6 mm, and paste to obtain the stress-strain cloud diagram and deformation diagram of the gradient dot matrix structure when the strain is 0.4, that is, obtain the total stress-strain cloud diagram representing the deformation of the gradient dot matrix structure.

[0059] Example 2: Gradient dot matrix structure compression simulation system based on layered finite element simulation, as shown in Figure 6 , including layered simulation module, first curve module, curve interception module, curve synthesis module, second curve module and superposition simulation module.

[0060] The layered simulation module is configured to establish an independent finite element model for each layer in the gradient lattice structure, and to apply the same boundary conditions and displacement to each finite element model to obtain simulation data of the corresponding layer. The first curve module is configured to construct a load-displacement curve according to the displacement data and the load data in the simulation data of each layer. The curve intercepting module is configured to calculate the densification displacement of each layer according to the densification strain of each layer, and to intercept the load-displacement curve part before the densification displacement as an effective curve. The curve synthesizing module is configured to synthesize the effective curves of each layer to obtain load data and displacement data of the gradient lattice structure. The second curve module is configured to construct a stress-strain curve according to the load data and the displacement data of the gradient lattice structure. The superposition simulation module is configured to match a strain layer and determine a corresponding stress value from the stress-strain curve according to a preset strain value, to convert the stress value into a load, to retrieve a corresponding stress-strain cloud atlas from the simulation data of each layer, and to obtain a total stress-strain cloud atlas representing deformation of the gradient lattice structure under the preset strain value by splicing the stress-strain cloud atlases of each layer.

[0061] Working principle: each layer can be regarded as a solid material after being crushed to densification, and each layer can be regarded as an isolated body for analysis when being compressed, so as to propose layered gradient simulation; when the simulation situation under a certain strain value needs to be queried, the stress-strain cloud atlas corresponding to each layer can be retrieved from the simulation data of each layer by converting the stress value into a load, and the total stress-strain cloud atlas representing deformation of the gradient lattice structure under the preset strain value can be obtained by splicing the stress-strain cloud atlases of each layer, without the need to perform comprehensive simulation from beginning to end, so that the simulation result is efficient and easy to converge, and the problems of large calculation amount, high time cost and difficulty in convergence in the finite element simulation of the gradient lattice structure can be effectively solved, so that the finite element simulation of the gradient lattice structure can be more widely applied.

[0062] Those skilled in the art will understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0063] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0064] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0065] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks Figure 1 one or more flow or blocks

[0066] The above detailed description has disclosed, by way of example, an embodiment of the present application. It is understood that the above description is merely a specific example of the present application and is not intended to limit the scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. A method for compression simulation of a gradient lattice structure based on hierarchical finite element simulation, characterized in that, The method comprises the following steps: An independent finite element model is established for each layer in the gradient lattice structure, and the same boundary conditions and displacement are applied to each finite element model to obtain simulation data of the corresponding layer; A load-displacement curve is constructed according to the displacement data and load data in the simulation data of each layer; The densification displacement of each layer is calculated according to the densification strain of the layer, and the part of the load-displacement curve before the densification displacement is taken as an effective curve; The load data and displacement data of the gradient lattice structure are obtained by synthesizing the effective curves of the layers; A stress-strain curve is constructed according to the load data and displacement data of the gradient lattice structure; The strain layer and the corresponding stress value are matched from the stress-strain curve according to a preset strain value, the stress value is converted into a load, the corresponding stress-strain cloud diagram is retrieved from the simulation data of each layer, and the stress-strain cloud diagrams of the layers are spliced to obtain a total stress-strain cloud diagram representing the deformation of the gradient lattice structure under the preset strain value.

2. The hierarchical finite element simulation-based compression simulation method of a gradient lattice structure according to claim 1, characterized in that, The boundary conditions and displacement applied to the finite element model are as follows: A compression direction displacement load is applied to the top section; The displacement in all directions is limited on the local section at the center of the bottom section; The displacement in the compression direction is limited on the remaining surfaces of the bottom section.

3. The hierarchical finite element simulation based compression simulation method of gradient lattice structures according to claim 1, characterized in that, The simulation data includes deformation data, stress and strain distribution state data, top section displacement data and load data.

4. The hierarchical finite element simulation-based compression simulation method of a gradient lattice structure according to claim 1, characterized in that, The construction process of the load-displacement curve is as follows: The obtained displacement and load data are listed in a load-displacement graph; All data points are smoothly connected to obtain the load-displacement curve of the corresponding layer.

5. The hierarchical finite element simulation based compression simulation method of gradient lattice structures according to claim 1, characterized in that, The process of intercepting the effective curve is as follows: The densification strain of the layer is found, and the densification displacement of the layer is obtained by multiplying the height of the layer in the compression direction; The densification strain of the layer is equivalent to the densification strain of the gradient lattice structure.

6. The hierarchical finite element simulation based compression simulation method of gradient lattice structures according to claim 1, characterized in that, The process of obtaining the load data and displacement data of the gradient lattice structure is as follows: Assuming that the a-th layer is taken as an example, an appropriate increment is taken, the displacement is superimposed from the displacement at which the load of the previous layer reaches the densification load for the first time, and the load corresponding to the displacement is recorded until the displacement reaches the densification displacement again; The recorded load is used to search for the displacement at which the load is reached for the first time in the load-displacement graph of the n-a-th layer which has not been crushed, the obtained n-a+1 displacement values are added to the value of a-1 times the densification displacement of the layer, and the sum is taken as the displacement of the gradient lattice structure and the load of the gradient lattice structure; This step is repeated until the n-th layer, where n is the number of layers of the gradient lattice structure, and 1≤a≤n.

7. The hierarchical finite element simulation based compression simulation method of gradient lattice structures according to claim 1, characterized in that, The construction process of the stress-strain curve is as follows: The strain of the gradient lattice structure is obtained by dividing the height of the gradient lattice structure in the compression direction by the displacement of the gradient lattice structure; The stress of the gradient lattice structure is obtained by dividing the load of the gradient lattice structure by the apparent cross-sectional area perpendicular to the compression direction; All data are listed in a stress-strain graph, and the simulation stress-strain curve is obtained after smooth connection.

8. A compression simulation system for a gradient lattice structure based on hierarchical finite element simulation, characterized in that, The method comprises the following steps: A hierarchical simulation module is configured to establish an independent finite element model for each layer in the gradient lattice structure, apply the same boundary conditions and displacement to each finite element model, and obtain simulation data of the corresponding layer; The first curve module is configured to construct a corresponding load-displacement curve according to displacement data and load data in each layer simulation data; The curve intercepting module is configured to calculate layer densification displacement according to layer densification strain, and intercept a load-displacement curve part before the layer densification displacement as an effective curve; The curve synthesizing module is configured to synthesize effective curves of each layer to obtain load data and displacement data of the gradient lattice structure; The second curve module is configured to construct a stress-strain curve according to the load data and the displacement data of the gradient lattice structure; The superposition simulation module is configured to match a strain layer and determine a corresponding stress value from the stress-strain curve according to a preset strain value, convert the stress value into a load, and then call corresponding stress-strain nephograms from simulation data of each layer, and obtain a total stress-strain nephogram representing deformation of the gradient lattice structure under the preset strain value by pasting stress-strain nephograms of each layer.

9. A computer terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the program to implement the gradient lattice structure compression simulation method based on layered finite element simulation in any one of claims 1-7.

10. A computer readable medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the gradient lattice structure compression simulation method based on layered finite element simulation in any one of claims 1-7.

Images