A parametric modeling and analysis method for infusion core materials based on APDL language

Abstract

The present invention discloses a parametric modeling and analysis method for a perfusion core material based on the APDL language, and relates to a field. The method comprises the following steps: Step 1, constructing a geometric model of the basic surface of the smallest unit of the perfusion core material based on the APDL language, determining the material properties of the core material model and the resin model respectively, and defining their unit types; Step 2, generating a finite element model of the smallest unit of the perfusion core material based on the APDL language; Step 3, generating a complete finite element model of the perfusion core material by multiple mirroring and copying based on the APDL language; Step 4, defining the finite element model analysis type based on the APDL language, applying a load to the perfusion core material, and solving it; Step 5, finally entering post-processing based on the APDL language to observe and analyze the calculation results, and outputting the deformation, stress, and displacement of the perfusion core material. The beneficial effect of the present invention is that the parametric modeling of the perfusion core material is realized by using the APDL language, which effectively improves efficiency and reduces errors.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of composite sandwich structure modeling and simulation, and specifically to a parametric modeling and analysis method for a perfusion core material based on the APDL language. Background Art

[0002] The disadvantages of traditional composite molding processes in terms of technology and environmental protection have gradually become more prominent with the increase in production capacity demand and the improvement of environmental standards, which has greatly hindered the promotion and application of composite materials. The vacuum infusion molding process came into being and has been widely used with its advantages of good performance, high efficiency and low cost. This process is mainly divided into two types: high permeability medium type and groove type. Compared with the high permeability medium type vacuum infusion process, the groove type vacuum injection molding process does not require non-reusable manufacturing process consumables such as high permeability medium and stripping materials, thereby reducing solid waste and production costs. At the same time, the permeability of the groove is higher than that of the high permeability medium, thereby increasing the infusion rate. However, grooves and hole structures of different geometric designs will directly affect the mechanical properties of the core material, and the mechanical properties of the core material have a significant impact on the mechanical properties of the sandwich panel.

[0003] In the search of related topics, it was found that domestic and foreign scholars have conducted few studies on core materials with different groove and hole structures, and the research is mainly carried out through experimental means, and less through numerical simulation. For example, the paper Influence of face / core interface on debond toughness of foam and balsa cored sandwich (TRUXELA. Journal of Sandwich Structures & Materials, 2006, 8(3)) and Effects of coremachining configuration on the debonding toughness of foam core sandwich panels (YOKOZEKI T, IWAMOTO K. Advanced Composite Materials, 2016, 25(1)) experimentally investigated the debonding toughness of two groove structures and four core materials with different groove and hole designs; the paper An investigation on the flexural properties of balsa and polymer foam core sandwich structures: Influence of core type and contour finishing options (FATHI A, WOLFF-FABRIS F, V, et al. Journal of Sandwich Structures & Materials, 2013, 15(5)) used a four-point bending test to investigate the bending properties of three slotted and perforated core materials and a non-perforated core material. These studies only used experimental methods to study slotted core materials, which was less economical and the data obtained was limited.

[0004] In addition, patent CN111460715A also discloses a static analysis method for a natural compensator based on the APDL language, which includes the following steps: 1. Create a geometric model of the natural compensator based on the APDL language, determine the material type, set material parameters, and define the unit type and properties; 2. Assign unit properties based on the APDL language, set the meshing level and select the meshing method, and generate a finite element model of the natural compensator by meshing; 3. Define the analysis type based on the APDL language, apply loads to the finite element model of the natural compensator, and perform solution calculations; 4. Enter the post-processor based on the APDL language to observe and analyze the calculation results to obtain the displacement and stress distribution of the natural compensator. Using the APDL language to achieve parametric modeling of the natural compensator improves modeling efficiency and systematically and comprehensively analyzes the displacement and stress of the natural compensator. However, this method divides the geometric modeling and finite element model generation into two steps, and has a narrow scope of application and low efficiency. Summary of the Invention

[0005] To address the shortcomings of the existing technology, the present invention provides a parametric modeling and analysis method for cast core materials based on the APDL language. It uses the APDL language to achieve parametric modeling of cast core materials with strong geometric periodicity. By changing the parameters, the modeling of the same problem can be repeated, effectively improving efficiency and reducing errors.

[0006] To achieve the above-mentioned purpose, the present invention is implemented through the following technical solutions:

[0007] A parametric modeling and analysis method for a cast core material based on the APDL language includes the following steps:

[0008] Step 1: Construct the geometric model of the smallest unit surface of the infusion core material based on the APDL language, determine the material properties of the core material model and the resin model respectively, and define their unit types;

[0009] Step 2: Generate a finite element model of the smallest unit of the infusion core material based on the APDL language;

[0010] Step 3: Generate a complete finite element model of the infusion core material by mirroring and copying multiple times based on the APDL language;

[0011] Step 4: Define the finite element model analysis type based on the APDL language, apply loads to the cast core material, and solve;

[0012] Step 5. Finally, enter the post-processing based on the APDL language to observe and analyze the calculation results, and output the deformation, stress and displacement of the cast core material.

[0013] Constructing the geometric model of the minimum unit basic surface of the infusion core material in the step 1 includes using the BLC4 command in the APDL language, inputting numerical values ​​at corresponding positions to generate a zero-thickness cuboid, using the CYL4 command to generate a quarter-circular surface, using the ASBA command to perform Boolean operations on the generated surface, and using the AVOLAP command to separate the overlapping parts of the two surfaces to form three surfaces, thereby creating the geometric model of the minimum unit basic surface.

[0014] The material properties in step 1 include elastic modulus and Poisson's ratio.

[0015] Generating a finite element model of the smallest unit of the infused core material based on the APDL language includes assigning unit attributes, selecting a meshing method and setting meshing specifications, meshing the basic surface of the smallest unit of the infused core material in step 1, and further directly stretching the meshing auxiliary unit to generate a finite element model of the smallest unit of the infused core material;

[0016] The allocation unit attributes use the TYPE command to set the unit type and the MAT command to set the material type.

[0017] The mesh division adopts LESIZE command, and the number of line segments is input to specify the number of line meshes. The mesh division method of the minimum unit basic surface of the pouring core material adopts MSHAPE to set the mesh shape; MSHKEY is used to select the mapping mesh; and AMESH command is used to perform mesh division of the minimum unit basic surface of the pouring core material.

[0018] The mesh division auxiliary unit is mesh200, and the complete finite element model of the infusion core material is generated by using the EXTOPT command to set the number of mesh segments on the stretch height; and using the VEXT command to set the stretch height value.

[0019] In the step three, the VSYMM command is used to set the body mirror symmetry plane and the finite element model of the smallest unit of the mirrored infusion core material, and the VGEN command is used to copy the finite element model of the smallest unit of the infusion core material to generate a complete finite element model of the infusion core material.

[0020] In the step 4, the finite element model analysis type is defined based on the APDL language, and the ANTYPE command is used to set it to a steady-state static solution.

[0021] In step 4, the load is applied by using ASEL to select the load application position, and the DA command is used to set the direction and magnitude of the surface displacement load.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] The present invention uses the APDL language to implement parametric modeling of cast core materials with strong geometric periodicity. Compared with the method of first establishing a geometric model and then dividing the grid on the geometric model in patent CN111460715A, the present invention uses grid auxiliary units to simultaneously generate a geometric model and a finite element model, which greatly simplifies the construction of the finite element model of the cast core material. Due to the characteristics of the cast core material containing grooves and through-hole processing structures, in which the through-holes are cylindrical and the grooves are usually rectangular grooves embedded in the surface of the core material, the method of the present invention can directly generate the geometric model and finite element model of the cast core material based on only the minimum unit basic surface model, and simultaneously complete the assignment of material properties and unit types. Moreover, since the slot size of the cast core material is not a fixed value, the final size of the cast core material is also composed of a series of replication and symmetry processing of the finite element model of the smallest unit of the cast core material. In related research, it is necessary to examine the effects of different apertures, groove sizes, cast core material sizes, etc. on the overall mechanical properties of the cast core material. By adopting the method of the present invention, it is only necessary to modify the geometric features of the geometric model of the smallest unit of the cast core material to directly modify the aperture size and groove size of all core material through holes. By modifying the parameters of the grid auxiliary unit, the size of the entire geometric model and the finite element model and the number of grids can be set, thereby improving research efficiency and reducing errors. The problems that may be caused by software compatibility issues are eliminated, the displacement and stress response of the cast core material are systematically analyzed, and effective guidance is provided to relevant researchers. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flow chart of a parametric modeling and analysis method for a perfusion core material based on the APDL language.

[0025] Figure 2 It is a geometric model diagram of the basic surface of the smallest unit of the infusion core material according to an embodiment of the present invention.

[0026] Figure 3 It is a mesh division diagram of the geometric model of the minimum unit basic surface of the infusion core material according to an embodiment of the present invention.

[0027] Figure 4 It is a finite element model diagram of the smallest unit of the infusion core material according to an embodiment of the present invention.

[0028] Figure 5 This is a complete finite element model diagram of the infusion core material according to an embodiment of the present invention.

[0029] Figure 6 It is a deformation diagram of the finite element calculation result of the infusion core material obtained by ANSYS calculation in an embodiment of the present invention.

[0030] Figure 7 It is a stress cloud diagram of the finite element calculation result of the infusion core material obtained by ANSYS in an embodiment of the present invention.

[0031] Figure 8 This is a z-direction displacement cloud diagram of the finite element calculation results of the infusion core material obtained by ANSYS in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the present application.

[0033] Step 1: Obtain the geometric parameters of the minimum unit basic surface of the infusion core material, as well as the material type, engineering parameters, unit type, and unit attributes of the core material model and resin model. Build a geometric model of the minimum unit basic surface of the infusion core material based on the APDL language. Assign the material type and parameters to the core material model and resin model respectively, and define their unit types and attributes to obtain the geometric model of the minimum unit basic surface of the infusion core material.

[0034] Step 2: Obtain a geometric model of the basic surface of the minimum unit of the infused core material, and generate a finite element model of the minimum unit of the infused core material based on the APDL language, including assigning unit attributes, selecting a meshing method and setting meshing specifications, meshing the basic surface of the minimum unit of the infused core material described in step 1, and further directly stretching the meshing auxiliary unit to generate a finite element model of the minimum unit of the infused core material, thereby obtaining a finite element model of the minimum unit of the infused core material;

[0035] Step 3: Obtain the finite element model of the smallest unit of the infusion core material, and mirror and copy the finite element model of the smallest unit of the infusion core material described in step 2 multiple times based on the APDL language to generate a complete finite element model of the infusion core material;

[0036] Step 4: Obtain a complete finite element model of the cast core material, define the finite element model analysis type based on the APDL language, apply loads according to different angles of mechanical properties of the cast core material, and solve the loads to obtain the calculation results.

[0037] Step 5: Obtain the calculation results described in step 4, enter post-processing in APDL language to observe and analyze the calculation results, output the deformation diagram and stress and displacement distribution cloud diagram in the tensile simulation, and obtain the deformation diagram and stress and displacement distribution in the tensile simulation.

[0038] Preferably, in step one, constructing the geometric model of the minimum unit basic surface of the infusion core material includes using the BLC4 command in the APDL language, inputting a numerical value in the command to generate a 0-thickness cuboid, using the CYL4 command to generate a quarter-circular surface, using the ASBA command to perform Boolean operations on the generated surface, and using the AVOLAP command to separate the overlapping parts of the two surfaces to form three surfaces, thereby creating a geometric model of the minimum unit basic surface.

[0039] Preferably, the material parameters include elastic modulus and Poisson's ratio of the core material and the resin, both of which are specified using the MP command.

[0040] Preferably, the unit type includes two solid185 units and one mesh200 unit, wherein the mesh200 unit is used to assist in volume mesh division, and both are defined using ET commands.

[0041] Preferably, in step 2, the mesh size is set using the LESIZE command, and the number of line segments is specified by inputting the number of line meshes. The meshing method for the minimum unit surface of the cast core material is to set the mesh shape using MSHAPE; select the mapped mesh using MSHKEY; and mesh the minimum unit surface of the cast core material using the AMESH command. The mesh properties are set using the TYPE command to set the unit type, and the MAT command to set the material type.

[0042] Preferably, the mesh division auxiliary unit is mesh200, and the direct stretching to generate a complete finite element model of the infusion core material uses the EXTOPT command to set the number of mesh segments on the stretching height; and uses the VEXT command to set the stretching height value.

[0043] Preferably, in step 3, the mirroring to generate a complete finite element model of the infusion core material is to use the VSYMM command to set the body mirror symmetry plane and the finite element model of the minimum unit of the mirrored infusion core material.

[0044] Preferably, the copying and generating of the complete finite element model of the perfusion core material is to use the VGEN command to copy the finite element model of the smallest unit of the perfusion core material to generate the complete finite element model of the perfusion core material.

[0045] Preferably, in step 4, the load is applied by using ASEL to select the load application position and using the DA command to set the direction and magnitude of the surface displacement load.

[0046] Preferably, the finite element analysis type is set to steady-state static solution using the ANTYPE command, the solution unit is entered using the / SOLU command, and the calculation and solution is started using SOLVE.

[0047] Preferably, in step five, the / POST command in the APDL language is used to enter post-processing, and the PLNSOL command is used to view the displacement and stress cloud maps.

[0048] Example:

[0049] In this embodiment, the perforated core material is a slotted and perforated core material with a geometric size of 60×60×50 (mm), consisting of 36 perforated core material minimum units, including 9 holes, 3 transverse grooves and 3 longitudinal grooves. The basic dimensions are shown in Table 1;

[0050] Table 1 Basic parameters of the infusion core material

[0051]

[0052] like Figure 1 As shown, a parametric modeling and analysis method for infusion core materials based on the APDL language includes the following steps:

[0053] Step 1: Based on the basic parameters of the perfusion core material and the overall geometric structure characteristics of the perfusion core material in Table 1, the geometric model size of the minimum unit basic surface of the perfusion core material of this embodiment is calculated to be 10×10 (mm). Only one-quarter of the hole needs to be drawn, and half of the groove width is set to 1 mm;

[0054] Use the BLC4 command in the APDL language to draw multiple times, input the value at the corresponding position to generate a 0-thickness cuboid, use the CYL4 command to generate a quarter-circular surface, use the ASBA command to perform Boolean operations on the generated surface, and use the AVOLAP command to separate the overlapping parts of the two surfaces to form three surfaces, thereby creating a geometric model of the minimum unit basic surface. Figure 2 As shown;

[0055] Use the MP command to define the material properties, elastic modulus and Poisson's ratio of the core material and resin. The specific values ​​are shown in Table 2:

[0056] Table 2 Material properties

[0057]

[0058] The ET command is used to define the element type, including two solid185 elements and one Mmesh200 element.

[0059] The second step is to use the LESIZE command and enter the number of line segments to specify the number of line grids. Finally, the two right-angled sides of the quarter hole section are divided into 4 parts, the curved side is divided into 4 parts, the side where the two right-angled sides of the hole section are located is divided into 9 parts, and the opposite side is divided into 2 parts. Figure 3 As shown, the mesh division method of the minimum unit basic surface of the perfusion core material is set by using MSHAPE to set the mesh shape; using the MSHKEY command to select the use of mapped mesh; using the AMESH command to perform mesh division of the minimum unit basic surface of the perfusion core material; using the TYPE command to set the unit type of the mesh attribute, and using the MAT command to set the material type;

[0060] Direct stretching generates a complete finite element model of the infusion core material. Use the EXTOPT command to set the number of mesh segments on the stretching height. This command is used four times in total, twice to generate the core material finite element model, and twice to generate the cylindrical resin and groove resin respectively. Use the VEXT command to set the stretching height value to generate the minimum unit finite element model. Figure 4 shown.

[0061] The third step is to use the VSYMM command to set the volume mirror symmetry plane and the finite element model of the minimum unit of the mirrored core material. This is done three times in total, namely, mirroring the minimum unit model generated for the first time about the z=0 plane, mirroring the unit model generated for the second time about the x=0 plane of the work plane coordinate offset by the WPOFFS command, and mirroring the unit model generated for the third time about the new work plane coordinate y=0 plane.

[0062] Use the VGEN command to copy the finite element model of the smallest unit of the infusion core material to generate a complete finite element model of the infusion core material. The command is executed twice. The first time, two copies are made along the x-axis to generate the unit model. The second time, the model generated last time is copied twice along the y-axis to finally generate the entire finite element model of the infusion core material. Figure 5 shown.

[0063] Step 4. Use ASEL to select the load application location, use the DA command to set the direction and size of the surface displacement load, fix all degrees of freedom of the fixture on one side, apply a vertical tensile load to the surface of the fixture on the other side, use the ANTYPE command to set it to steady-state static solution, use the / SOLU command to enter the solution unit, and start the calculation with SOLVE.

[0064] Step 5: Use the / POST command in APDL language to enter post-processing, and use the PLNSOL command to view the deformation map, displacement cloud map, and stress cloud map;

[0065] Use the PLDISP,1 command to output the deformation diagram and use the / DSCALE command to amplify the deformation by 3 times. Figure 6, use PLNSOL command to output equivalent stress cloud diagram respectively. Figure 7 , output z-direction displacement cloud map see Figure 8 .

[0066] Depend on Figure 6 It can be seen that the maximum deformation is about 1.03mm, and Figure 8 The maximum displacement in the z direction is consistent with that shown by Figure 7 It can be seen that the maximum stress is mainly distributed at the bottom of the cast core material, which is the most prone to failure.

Claims

1. A parametric modeling and analysis method for infusion core material based on APDL language, characterized in that: The following steps are involved: Step 1: Construct the geometric model of the minimum unit basic surface of the infusion core material based on the APDL language, determine the material properties of the core material model and the resin model respectively, and define their unit types; Step 2: Generate a finite element model of the smallest unit of the infusion core material based on the APDL language; Step 3: Generate a complete finite element model of the infusion core material by mirroring and copying multiple times based on the APDL language; Step 4: Define the finite element model analysis type based on the APDL language, apply loads to the poured core material, and solve; Step 5: Finally, enter the post-processing based on APDL language to observe and analyze the calculation results, and output the deformation, stress and displacement of the injection core material; The APDL language-based method for generating a finite element model of the smallest unit of the poured core material includes allocating unit attributes, selecting a meshing method and setting meshing specifications, meshing the basic surface of the smallest unit of the poured core material in step 1, and further directly stretching the meshing auxiliary unit to generate a finite element model of the smallest unit of the poured core material.

2. The APDL-based parametric modeling and analysis method for infusion core materials according to claim 1, characterized in that: The step 1 of constructing the geometric model of the minimum unit basic surface of the infusion core material includes using the BLC4 command in the APDL language, inputting numerical values ​​at corresponding positions to generate a 0-thickness cuboid, using the CYL4 command to generate a quarter-circular surface, using the ASBA command to perform Boolean operations on the generated surface, and using the AVOLAP command to separate the overlapping parts of two surfaces to form three surfaces, thereby creating a geometric model of the minimum unit basic surface.

3. The parametric modeling and analysis method of the infusion core material based on APDL language according to claim 1, characterized in that: The material properties in step 1 include elastic modulus and Poisson's ratio.

4. The APDL-based parametric modeling and analysis method for infusion core materials according to claim 1, characterized in that: The allocation unit attributes use the TYPE command to set the unit type and the MAT command to set the material type.

5. The APDL-based parametric modeling and analysis method for infusion core materials according to claim 1, characterized in that: The mesh division adopts LESIZE command, and the number of line segments is input to specify the number of line meshes. The mesh division method of the minimum unit basic surface of the infusion core material adopts MSHAPE to set the mesh shape; MSHKEY is used to select the use of mapping grid; and AMESH command is used to mesh the minimum unit basic surface of the infusion core material.

6. The APDL-based parametric modeling and analysis method for infusion core materials according to claim 1, characterized in that: The mesh division auxiliary unit is mesh200. When generating a complete finite element model of the infusion core material, the EXTOPT command is used to set the number of mesh segments on the stretching height; and the VEXT command is used to set the stretching height value.

7. The APDL-based parametric modeling and analysis method for infusion core materials according to claim 1, characterized in that: In the step three, the VSYMM command is used to set the volume mirror symmetry plane and the finite element model of the smallest unit of the mirrored infusion core material, and the VGEN command is used to copy the finite element model of the smallest unit of the infusion core material to generate a complete finite element model of the infusion core material.

8. The APDL-based parametric modeling and analysis method for infusion core materials according to claim 1, characterized in that: In the step 4, the finite element model analysis type is defined based on the APDL language, and the ANTYPE command is used to set it to a steady-state static solution.

9. The APDL-based parametric modeling and analysis method for infusion core materials according to claim 1, characterized in that: In step 4, the load is applied by using ASEL to select the load application position, and the DA command is used to set the direction and size of the surface displacement load.

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