Simulation grid size correction factor curved surface calibration method and system and medium

Abstract

The invention provides a grid size correction factor curved surface calibration method for simulation. The method comprises the following steps: determining displacement boundary conditions of a numerical model in X and Y directions under different stress triaxes; carrying out numerical model simulation by adopting the displacement boundary conditions, extracting constraint reaction force, and determining load displacement boundary conditions of the sample under different stress triaxes in combination with the constraint reaction force; dividing the numerical model into a plurality of size grids; simulating to obtain fracture strain under grids of different sizes, and fitting to obtain a grid size correction factor curve; and combining the grid size correction factor curves under different stress triaxes to generate a grid size correction factor curved surface taking the grid size as the X axis, the stress triaxes as the Y axis and the correction factor as the Z axis. According to the calibration method provided by the invention, the problem of difference of grid size correction factors under different stress triaxes can be solved, and simulated fracture correction under different stress triaxes and grid sizes can be accurately realized.

Description

Technical Field

[0001] The present invention relates to the field of numerical simulation, and particularly relates to a method, system and medium for calibrating a mesh size correction factor surface for simulation based on stress triaxiality. Background Art

[0002] In automotive safety simulation, due to the requirements of specimen size and calculation efficiency, there are significant differences between the meshes (5 mm - 10 mm) used in component test simulation and vehicle crash simulation and the meshes (0.1 mm - 0.5 mm) used for material card calibration. This results in large differences in the prediction of element fracture for the calibrated material cards in component test simulation and vehicle crash simulation. Therefore, the industry generally uses a mesh size correction factor curve to scale the fracture curve under different element meshes.

[0003] Traditional methods for calibrating the mesh size correction factor curve usually perform simulation through uniaxial tensile tests, simulate different mesh models, extract the ratio of the fracture strain of different mesh models to the fracture strain of the smallest mesh model as the mesh size correction factor points, and then generate the mesh size correction factor curve by smoothly connecting multiple points. However, this method is only applicable to the case of uniaxial tensile stress triaxiality and has poor adaptability under other stress triaxialities. Summary of the Invention

[0004] A method, system and medium for calibrating a mesh size correction factor surface for simulation are proposed for numerical models with different stress triaxialities and mesh sizes, aiming to solve the problem of differences in mesh size correction factors under different stress triaxialities.

[0005] The technical solution adopted by the present invention is as follows: A method for calibrating a mesh size correction factor surface for simulation includes:

[0006] Determine the displacement boundary conditions in the X and Y directions of the numerical model under different stress triaxialities;

[0007] Perform numerical model simulation using the displacement boundary conditions, extract the constraint reaction force, and determine the load-displacement boundary conditions of the specimen under different stress triaxialities in combination with the constraint reaction force;

[0008] Divide the numerical model into multiple size meshes;

[0009] Perform numerical model simulation using the load-displacement boundary conditions to obtain the fracture strains under different size meshes, and fit to obtain the mesh size correction factor curve;

[0010] Combine the mesh size correction factor curves under different stress triaxialities to generate a mesh size correction factor surface with the mesh size as the X-axis, the stress triaxiality as the Y-axis, and the mesh size correction factor as the Z-axis.

[0011] As a preferred solution, the method for determining the displacement boundary conditions includes:

[0012]

[0013] where u x is the boundary displacement of the numerical model in the X direction, ε x is the boundary strain in the X direction, and ω is the length of the numerical model in the X direction;

[0014]

[0015] where u y is the boundary displacement of the numerical model in the Y direction, ε y is the boundary strain in the Y direction, and h is the width of the numerical model in the Y direction;

[0016]

[0017] where α is the stress ratio in the X / Y direction;

[0018]

[0019] where η is the stress triaxiality.

[0020] As a preferred solution, the method for determining the load-displacement boundary conditions of the specimen under different stress triaxialities includes:

[0021] Apply the displacement boundary conditions in the X and Y directions corresponding to the stress triaxiality to the numerical model, and simulate to obtain the constraint reaction forces in the X and Y directions;

[0022] Combine the displacement boundary condition in the X direction with the constraint reaction force in the Y direction or combine the displacement boundary condition in the Y direction with the constraint reaction force in the X direction as the load-displacement boundary conditions of the specimen under different stress triaxialities.

[0023] As a preferred solution, the division of the numerical model into multiple size meshes includes: dividing the numerical model into meshes of at least 5 sizes.

[0024] As a preferred solution, the numerical model is respectively divided into meshes with sizes of 0.5 mm, 1 mm, 2 mm, 5 mm, and 10 mm.

[0025] As a preferred solution, the PCHIP interpolation is used to fit the mesh size correction factor curve.

[0026] In a second aspect of the present invention, a system is proposed, which includes a memory and a processor. A computer program corresponding to the calibration method for the mesh size correction factor surface for simulation as described in the first aspect can be loaded and executed by the processor and is stored on the memory.

[0027] In a third aspect of the present invention, a computer-readable storage medium is proposed, on which computer program instructions are stored. When the program instructions are executed by a processor, they are used to implement the process corresponding to the calibration method for the mesh size correction factor surface for simulation as described in the first aspect.

[0028] Compared with the prior art, the beneficial effects of adopting the above technical solutions are as follows: The calibration method proposed by the present invention can solve the problem of differences in the mesh size correction factor under different stress triaxialities, accurately achieve simulation calibration for different stress triaxialities and mesh sizes, and provide more reliable accuracy guarantees for the simulation design optimization of components and the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flowchart of the calibration for the mesh size correction factor surface for simulation proposed by the present invention.

[0030] Figure 2 It is a flowchart of the calibration implementation in an embodiment of the present invention.

[0031] Figure 3 It is a schematic diagram of mesh division in an embodiment of the present invention.

[0032] Figure 4 It is a schematic diagram of the simulation comparison between the present invention and the traditional method.

[0033] Figure 5 It is a comparison diagram of the component drop hammer simulation curves obtained by using the traditional calibration method and the calibration method of the present invention.

[0034] Figure 6 It is a schematic diagram of the component drop hammer simulation comparison obtained by using the traditional calibration method and the calibration method of the present invention. Among them, (a) is the test fracture surface, (b) is the simulation fracture surface of the traditional method, and (c) is the simulation fracture surface of the present invention.

[0035] Figure 7 A comparison diagram of the component three-point bending simulation curves obtained by using the traditional calibration method and the calibration method of the present invention.

[0036] Figure 8 It is a schematic diagram of the component three-point bending simulation comparison obtained by using the traditional calibration method and the calibration method of the present invention. Among them, (a) is the test fracture surface, (b) is the simulation fracture surface of the traditional method, and (c) is the simulation fracture surface of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar modules or modules with the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as a limitation of the present application. On the contrary, the embodiments of the present application include all changes, modifications, and equivalents that fall within the spirit and scope of the appended claims.

[0038] To solve the problem of differences in the mesh size correction factor under different stress triaxialities, an embodiment of the present application proposes a method for calibrating the mesh size correction factor surface for simulation. Please refer to Figure 1 、 Figure 2 , and the specific solution is as follows:

[0039] Step 1: Determine the displacement boundary conditions of the numerical model in the X and Y directions under different stress triaxialities.

[0040] In this embodiment, the displacement boundary conditions under different stress triaxialities are mainly determined by using formulas (1) to (4):

[0041]

[0042] Among them, u x is the displacement of the numerical model in the X direction, ε x is the strain in the X direction, and ω is the length of the numerical model in the X direction;

[0043]

[0044] Among them, u y is the displacement of the numerical model in the Y direction, ε y is the strain in the Y direction, and h is the width of the numerical model in the Y direction;

[0045]

[0046] Among them, α is the stress ratio in the X and Y directions;

[0047]

[0048] Among them, η is the stress triaxiality.

[0049] Step 2: Perform numerical model simulation using the displacement boundary conditions, extract the constraint reaction force, and determine the load-displacement boundary conditions of the specimen under different stress triaxialities in combination with the constraint reaction force.

[0050] In this embodiment, boundary conditions in the X and Y directions corresponding to the stress triaxiality are first applied to the numerical model, and the constraint reaction forces in the X and Y directions are extracted after simulation. Then, the displacement boundary condition in the X direction is combined with the constraint reaction force in the Y direction, or the displacement boundary condition in the Y direction is combined with the constraint reaction force in the X direction, as the load-displacement boundary condition of the specimen under different stress triaxialities.

[0051] Step 3: Divide the numerical model into grids of multiple sizes.

[0052] To ensure the accuracy of the simulation, in this embodiment, the numerical model is divided into grids of at least 5 sizes. Preferably, the numerical model is divided into grids with sizes of 0.5 mm, 1 mm, 2 mm, 5 mm, and 10 mm respectively. In practical applications, other grid sizes and quantities can also be divided. Figure 3 Shows numerical models with different grid sizes under various stress triaxialities.

[0053] Step 4: Use the load-displacement boundary condition to perform numerical model simulation to obtain the fracture strain under different grid sizes, and fit to obtain the grid size correction factor curve.

[0054] In this step, the load-displacement boundary condition can be used to perform numerical model simulation to extract the fracture strain corresponding to different grid sizes, and the PCHIP interpolation is used to fit the grid size correction factor curve, which is added to the material card.

[0055] Step 5: Combine the grid size correction factor curves under different stress triaxialities to generate a grid size correction factor surface with the grid size as the X-axis, the stress triaxiality as the Y-axis, and the grid size correction factor as the Z-axis.

[0056] Finally, by combining the grid size correction factor curves under different stress triaxialities, the required grid size correction factor surface can be generated as the basis for material parameter optimization.

[0057] Please refer to Figure 4 , which shows the grid size correction factor surfaces obtained by the traditional calibration method and the calibration method proposed in the present invention. The present invention takes into account the influence of different stress triaxialities on the grid size correction factor, and the simulated grid size correction factor surface is more in line with the actual situation.

[0058] Figure 5 and Figure 6 For the comparison of the drop hammer simulation of parts obtained by the traditional calibration method and the calibration method of the present invention, the comparison is carried out from two aspects of the load curve and the fracture morphology. The test results obtained by the calibration method of the present invention are better than those of the traditional method.

[0059] Figure 7 and Figure 8For the three-point bending simulation comparison of components obtained by using the traditional calibration method and the calibration method of the present invention, the comparison is carried out from two aspects of the load curve and the fracture morphology, and the test results obtained by the calibration method of the present invention are better than those of the traditional method.

[0060] An embodiment of the present invention provides a system, including a memory and a processor, and a computer program capable of being loaded and executed by the processor and corresponding to the simulation grid size correction factor surface calibration method as described above is stored on the memory.

[0061] In particular, according to the embodiments of the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes program codes for executing the methods shown in the flowcharts.

[0062] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the two. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, the computer-readable storage medium can be any tangible medium that contains or stores a program, and the program can be used by or in combination with an instruction execution system, apparatus, or device. In the present application, the computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, in which the computer-readable program code is carried. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, and the computer-readable medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted by any suitable medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0063] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present application. Among them, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the above-mentioned module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, as well as the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0064] The units involved in the embodiments described in the present application can be implemented in software or in hardware, and the described units can also be provided in a processor. Among them, the names of these units do not constitute a limitation on the units themselves in some cases.

[0065] On the other hand, the present application also provides a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the method for calibrating the simulation mesh size correction factor surface described in the above embodiments.

[0066] On the other hand, the present application also provides a computer-readable medium. The computer-readable medium may be included in the electronic device described in the above embodiments; or it may exist separately and not be assembled into the electronic device. The above computer-readable medium carries one or more programs. When the above one or more programs are executed by an electronic device, the electronic device implements the method for calibrating the simulation mesh size correction factor surface described in the above embodiments.

[0067] It should be noted that although several modules or units of the device for action execution are mentioned in the above detailed description, such a division is not mandatory. In fact, according to the embodiments of the present application, the features and functions of the two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0068] Through the description of the above embodiments, those skilled in the art can easily understand that the example embodiments described herein can be implemented by software or by a combination of software and necessary hardware. Therefore, the technical solutions according to the embodiments of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (such as a personal computer, a server, a touch terminal, or a network device, etc.) to execute the method according to the embodiments of the present application.

[0069] For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances; the accompanying drawings in the embodiments are used to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and shown in the accompanying drawings herein can be arranged and designed in various different configurations.

[0070] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for calibrating a mesh size correction factor surface for simulation, characterized in that: include: Determine the displacement boundary conditions of the numerical model in the X and Y directions under different stress triaxialities; The displacement boundary conditions are used to simulate the numerical model, extract the constraint reaction force, and determine the load displacement boundary conditions of the specimen under different stress triaxialities in combination with the constraint reaction force; Divide the numerical model into grids of multiple sizes; The numerical model simulation is carried out using load-displacement boundary conditions to obtain the fracture strain under different mesh sizes, and the mesh size correction factor curve is obtained by fitting. The mesh size correction factor curves under different stress triaxiality are combined to generate a mesh size correction factor surface with mesh size as X-axis, stress triaxiality as Y-axis and mesh size correction factor as Z-axis.

2. The method for calibrating a mesh size correction factor surface for simulation according to claim 1, characterized in that: The method for determining the displacement boundary condition includes: Among them, u x is the boundary displacement in the X direction of the numerical model, ε x is the boundary strain in the X direction, ω is the length of the numerical model in the X direction; Among them, u y is the boundary displacement in the Y direction of the numerical model, ε y is the boundary strain in the Y direction, h is the width of the numerical model in the Y direction; Where α is the stress ratio in the X\Y direction; Where η is the stress triaxiality.

3. The method for calibrating a mesh size correction factor surface for simulation according to claim 1, characterized in that: The method for determining the load-displacement boundary conditions of the specimen under different stress triaxialities includes: Displacement boundary conditions in the X and Y directions corresponding to the stress triaxiality are applied to the numerical model, and the constraint reaction forces in the X and Y directions are obtained by simulation; The displacement boundary condition in the X direction is combined with the constraint reaction force in the Y direction, or the displacement boundary condition in the Y direction is combined with the constraint reaction force in the X direction as the load-displacement boundary condition of the specimen under different stress triaxialities.

4. The method for calibrating a mesh size correction factor surface for simulation according to claim 1, characterized in that: The dividing the numerical model into grids of multiple sizes includes: dividing the numerical model into grids of at least 5 sizes.

5. The method for calibrating a mesh size correction factor surface for simulation according to claim 4, characterized in that: The numerical model is divided into grids with sizes of 0.5 mm, 1 mm, 2 mm, 5 mm, and 10 mm respectively.

6. The method for calibrating a mesh size correction factor surface for simulation according to claim 1, characterized in that: PCHIP interpolation is used to fit the grid size correction factor curve.

7. A system, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executes the method for calibrating a mesh size correction factor surface for simulation as claimed in any one of claims 1 to 6.

8. A computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the program instructions are executed by a processor, they are used to implement a process corresponding to the method for calibrating a mesh size correction factor surface for simulation as described in any one of claims 1 to 6.

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