Quick modeling method and module for finite element model of sandwich structure

Abstract

The invention belongs to the technical field of electrical data processing, and particularly relates to a fast modeling method and module for a finite element model of a sandwich structure, and the method comprises the steps: stretching a two-dimensional mesh surface to obtain a three-dimensional model composed of hexahedron units, and stretching each rectangular mesh of the two-dimensional mesh surface to obtain one hexahedron unit; acquiring a boundary node set of the two-dimensional grid surface, and taking a first boundary node in the boundary node set as a search node; finding out hexahedron units corresponding to the finding nodes meeting a preset direction condition, when the number of the found hexahedron units is two, judging the hexahedron units meeting the preset direction condition, and carrying out a first type of operation on the hexahedron units, and when the number of the found hexahedron units is one, carrying out a second type of operation on the hexahedron units; and deleting the search nodes in the boundary node set, and taking the next sequential boundary node in the boundary node set as the search nodes until the boundary node set is an empty set. And outputting the operated three-dimensional model.

Description

Technical Field

[0001] The present application belongs to the technical field of electrical data processing, and in particular relates to a finite element model rapid modeling method and module for a sandwich structure. Background Art

[0002] For composite sandwich structures, in order to better simulate the physical structure, when establishing the finite element model, the sandwich layer needs to be built as a three-dimensional model. The beveled area of ​​the sandwich layer is a difficult point in modeling. It is necessary to establish pentahedral units at the boundary, and there are certain requirements for the unit direction, and tetrahedral units are established at the corners. For the above modeling work, the conventional operation process is to first generate a volume mesh by sweeping the inner surface mesh, and then modify the boundary unit through the splitting command to generate the required beveled area. If it is manually operated, it can only be modified one unit at a time, which is a huge workload. Summary of the invention

[0003] In order to solve the above problems, the present application provides a method for rapid modeling of a finite element model of a sandwich structure, step S1: a three-dimensional model composed of hexahedral units is obtained by stretching a two-dimensional mesh surface, and each rectangular mesh of the two-dimensional mesh surface is stretched to obtain a hexahedral unit;

[0004] Step S2: obtaining a boundary node set of the two-dimensional grid surface, and taking the first boundary node in the boundary node set as the search node;

[0005] Step S3: Find out the hexahedral units corresponding to the search nodes that meet the preset direction conditions. When there are two hexahedral units found, determine the hexahedral unit that meets the preset direction conditions and perform the first type of operation on the hexahedral unit. When there is only one hexahedral unit found, perform the second type of operation on the hexahedral unit.

[0006] Step S4: Delete the search node in the boundary node set, and use the next boundary node in the boundary node set as the search node, and jump to step S2 until the boundary node set is an empty set.

[0007] Step S5: Output the three-dimensional model after the operation.

[0008] In some optional embodiments, the first type of operation includes operating the hexahedral cells into pentahedral cells.

[0009] In some alternative embodiments, the second type of operation includes operations on pentahedral cells to tetrahedral cells.

[0010] In some optional implementations, the method for determining the found hexahedral unit in step S3 includes:

[0011] The search node is taken as node G1, the non-boundary node adjacent to node G1 on the two-dimensional grid surface is taken as node G2, and the node in the stretching direction of node G2 is taken as G3;

[0012] Calculate the direction vector obtained by cross-producting the vector from node G1 to node G2 and the vector from node G2 to node G3.

[0013] When nodes G1, G2, and G3 have nodes along the direction vector pointing to them, two hexahedral units are found; when nodes G1, G2, and G3 have no nodes along the direction vector pointing to them, one hexahedral unit is found.

[0014] In some optional implementations, the method for determining the hexahedral unit that meets the preset direction condition includes: setting the nodes pointed to by the direction vector along the node G1, the node G2, and the node G3 as the node G4, the node G5, and the node G6 respectively;

[0015] The hexahedral units where the nodes G1, G2, G3, G4, G5, and G6 are located are hexahedral units that meet the preset direction conditions.

[0016] In some optional implementations, the first type of operation includes: generating a pentahedron from the node G1, the node G2, the node G3, the node G4, the node G5, and the node G6.

[0017] In some optional implementations, the second type of operation includes: removing the pentahedron generated by the previous node search from node G6, and generating a tetrahedron through nodes G1, G2, G3, G4, and G5.

[0018] Combination Figure 2-Figure 3 As shown: The solid node H1 in the figure G4 H1 G1 (H2 G4 )H2 G1 is the boundary node of the surface element, where the solid node H1 G1 (H2 G4 ) is used to find the boundary point, and the search point is used as the node G1 of the pentahedral unit, that is, the search boundary point H2 is taken G4 For node G1, follow another node H2 to find the boundary point G3 This is the second node G2, and the node H2 is obtained by adding 4 to the node position of the hexahedral unit G7 For the third node G3, when nodes G1, G2, and G3 point to nodes along the direction vector, two hexahedral units are found, that is, by finding the boundary point H2 G4 We can find two hexahedrons H1 and H2 connected to it;

[0019] Calculate the direction vector obtained by cross-producting the vector from node G1 to node G2 and the vector from node G2 to node G3, and set the nodes pointed to by nodes G1, G2, and G3 along the direction vector as nodes G4, G5, and G6 respectively; another boundary point H2 on the bottom surface of the hexahedral unit G1 is the fourth node G4 of the pentahedral element, and the last node H2 remaining in the bottom node G2 The fifth node G5 of the pentahedral element, the node H2 obtained by adding 4 to the node position G6 For the sixth node G6 of the pentahedral unit, nodes G1, G2, G3, G4, G5, and G6 are generated into a pentahedron. Thus, the conversion from hexahedral unit to pentahedral unit is completed. Another boundary point H2 in the bottom node of the hexahedral unit G1 Find the next node.

[0020] A finite element model rapid modeling module for a sandwich structure, comprising:

[0021] Initial model building module: used to generate a three-dimensional model. The three-dimensional model is obtained by stretching a two-dimensional mesh surface. The three-dimensional model has hexahedral units. Each rectangular mesh of the two-dimensional mesh surface is stretched to obtain a hexahedral unit.

[0022] Search node module: used to obtain the boundary node set of the two-dimensional grid surface, and the first boundary node in the boundary node set is used as the search node;

[0023] Operation module: used to find out the hexahedral unit corresponding to the search node that meets the preset direction condition, when there are two hexahedral units found, determine the hexahedral unit that meets the preset direction condition, and perform the first type of operation on the hexahedral unit, and when there is only one hexahedral unit found, perform the second type of operation on the hexahedral unit;

[0024] Jump module: used to delete the search node in the boundary node set, and use the next boundary node in the boundary node set as the search node, and input it into the operation module until the boundary node set is an empty set;

[0025] Output module: output the 3D model after operation.

[0026] In some optional implementations, the method further includes: a judgment module:

[0027] Node label generation unit: the search node is taken as node G1, the non-boundary node adjacent to node G1 and located on the two-dimensional grid surface is taken as node G2, and the node of node G2 in the stretching direction is taken as G3;

[0028] Calculation unit: used to calculate the direction vector obtained by cross-producting the vector from node G1 to node G2 and the vector from node G2 to node G3.

[0029] Judgment unit: when nodes G1, G2 and G3 point to nodes along the direction vector, two hexahedral units are output; when nodes G1, G2 and G3 point to no nodes along the direction vector, one hexahedral unit is output.

[0030] In some optional implementations, the judgment module further includes:

[0031] A node label generating unit: used for setting the nodes pointed to by the node G1, the node G2 and the node G3 along the direction vector as the node G4, the node G5 and the node G6 respectively;

[0032] Determine the unit: determine whether the hexahedral unit where the node G1, the node G2, the node G3, the node G4, the node G5, and the node G6 are located is a hexahedral unit that meets the preset direction conditions.

[0033] In some optional implementations, the pentahedron generation unit is used to generate a pentahedron from the node G1, the node G2, the node G3, the node G4, the node G5, and the node G6.

[0034] In some optional implementations, the tetrahedron generation unit is used to remove the pentahedron generated by the previous search node from node G6, and generate a tetrahedron through nodes G1, G2, G3, G4, and G5.

[0035] The advantages of this application include: the adoption of methods and modules can improve the modeling efficiency of the finite element model of the composite sandwich structure, greatly reducing the complexity of the work. Since the establishment of the beveled area can directly ensure the consistency of the unit direction, a good foundation is established for the subsequent addition of various anisotropic materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 are the pentahedral elements after labeling.

[0037] Figure 2 are two hexahedral units.

[0038] Figure 3 are two pentahedral elements generated from hexahedral elements.

[0039] Figure 4 It is the three-dimensional model diagram of step S1.

[0040] Figure 5 It is the three-dimensional model diagram of step S5. DETAILED DESCRIPTION

[0041] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be further described in detail in detail and in detail in conjunction with the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments in the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0042] As shown in the figure, the present application provides a method for rapid modeling of a finite element model of a sandwich structure, step S1: a three-dimensional model composed of hexahedral units is obtained by stretching a two-dimensional mesh surface, and each rectangular mesh of the two-dimensional mesh surface is stretched to obtain a hexahedral unit;

[0043] Step S2: obtaining a boundary node set of the two-dimensional grid surface, and taking the first boundary node in the boundary node set as the search node;

[0044] Step S3: Find out the hexahedral units corresponding to the search nodes that meet the preset direction conditions. When there are two hexahedral units found, determine the hexahedral unit that meets the preset direction conditions and perform the first type of operation on the hexahedral unit. When there is only one hexahedral unit found, perform the second type of operation on the hexahedral unit.

[0045] Step S4: Delete the search node in the boundary node set, and use the next boundary node in the boundary node set as the search node, and jump to step S2 until the boundary node set is an empty set.

[0046] Step S5: Output the three-dimensional model after the operation.

[0047] Preferably, the first type of operation includes operating hexahedral cells into pentahedral cells.

[0048] Preferably, the second type of operation includes the operation of pentahedral cells into tetrahedral cells.

[0049] Preferably, the method for determining the found hexahedral unit in step S3 includes:

[0050] The search node is taken as node G1, the non-boundary node adjacent to node G1 on the two-dimensional grid surface is taken as node G2, and the node in the stretching direction of node G2 is taken as G3;

[0051] Calculate the direction vector obtained by cross-producting the vector from node G1 to node G2 and the vector from node G2 to node G3.

[0052] When nodes G1, G2, and G3 have nodes along the direction vector pointing to them, two hexahedral units are found; when nodes G1, G2, and G3 have no nodes along the direction vector pointing to them, one hexahedral unit is found.

[0053] Preferably, the method for determining the hexahedral unit that meets the preset direction condition includes: setting the nodes pointed to by the direction vector along the node G1, the node G2, and the node G3 as the node G4, the node G5, and the node G6 respectively;

[0054] The hexahedral units where the nodes G1, G2, G3, G4, G5, and G6 are located are hexahedral units that meet the preset direction conditions.

[0055] Preferably, the first type of operation includes: generating a pentahedron from the node G1, the node G2, the node G3, the node G4, the node G5, and the node G6.

[0056] Preferably, the second type of operation includes: removing the pentahedron generated by the previous node search from the node G6, and generating a tetrahedron through the nodes G1, G2, G3, G4 and G5.

[0057] A finite element model rapid modeling module for a sandwich structure, comprising:

[0058] Initial model building module: used to generate a three-dimensional model. The three-dimensional model is obtained by stretching a two-dimensional mesh surface. The three-dimensional model has hexahedral units. Each rectangular mesh of the two-dimensional mesh surface is stretched to obtain a hexahedral unit.

[0059] Search node module: used to obtain the boundary node set of the two-dimensional grid surface, and the first boundary node in the boundary node set is used as the search node;

[0060] Operation module: used to find out the hexahedral unit corresponding to the search node that meets the preset direction condition, when there are two hexahedral units found, determine the hexahedral unit that meets the preset direction condition, and perform the first type of operation on the hexahedral unit, and when there is only one hexahedral unit found, perform the second type of operation on the hexahedral unit;

[0061] Jump module: used to delete the search node in the boundary node set, and use the next boundary node in the boundary node set as the search node, and input it into the operation module until the boundary node set is an empty set;

[0062] Output module: output the 3D model after operation.

[0063] Preferably, it further includes: a judgment module:

[0064] Node label generation unit: the search node is taken as node G1, the non-boundary node adjacent to node G1 and located on the two-dimensional grid surface is taken as node G2, and the node of node G2 in the stretching direction is taken as G3;

[0065] Calculation unit: used to calculate the direction vector obtained by cross-producting the vector from node G1 to node G2 and the vector from node G2 to node G3.

[0066] Judgment unit: when nodes G1, G2 and G3 point to nodes along the direction vector, two hexahedral units are output; when nodes G1, G2 and G3 point to no nodes along the direction vector, one hexahedral unit is output.

[0067] Preferably, the judgment module further includes:

[0068] A node label generating unit: used for setting the nodes pointed to by the node G1, the node G2 and the node G3 along the direction vector as the node G4, the node G5 and the node G6 respectively;

[0069] Determine the unit: determine whether the hexahedral unit where the node G1, the node G2, the node G3, the node G4, the node G5, and the node G6 are located is a hexahedral unit that meets the preset direction conditions.

[0070] Preferably, the pentahedron generating unit is used to generate a pentahedron from the nodes G1, G2, G3, G4, G5 and G6.

[0071] Preferably, the tetrahedron generating unit is used to remove the pentahedron generated by the previous search node from the node G6, and generate a tetrahedron through the nodes G1, G2, G3, G4 and G5.

[0072] The advantages of this application include: the adoption of methods and modules can improve the modeling efficiency of the finite element model of the composite sandwich structure, greatly reducing the complexity of the work. Since the establishment of the beveled area can directly ensure the consistency of the unit direction, a good foundation is established for the subsequent addition of various anisotropic materials.

[0073] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for rapid finite element modeling of a sandwich structure, characterized by: Step S1: a three-dimensional model composed of hexahedral units is obtained by stretching a two-dimensional mesh surface, and each rectangular mesh of the two-dimensional mesh surface is stretched to obtain a hexahedral unit; Step S2: obtaining a boundary node set of the two-dimensional grid surface, and taking the first boundary node in the boundary node set as the search node; Step S3: Find out the hexahedral units corresponding to the search nodes that meet the preset direction conditions. When there are two hexahedral units found, determine the hexahedral unit that meets the preset direction conditions and perform the first type of operation on the hexahedral unit. When there is only one hexahedral unit found, perform the second type of operation on the hexahedral unit. Step S4: Delete the search node in the boundary node set, and use the next boundary node in the boundary node set as the search node, and jump to step S2 until the boundary node set is an empty set. Step S5: Output the three-dimensional model after the operation.

2. The finite element model rapid modeling method of a sandwich structure according to claim 1, characterized in that: The first type of operations involves manipulating hexahedral cells into pentahedral cells.

3. The finite element model rapid modeling method of a sandwich structure according to claim 2, characterized in that: The second type of operations involves the manipulation of pentahedral elements into tetrahedral elements.

4. The finite element model rapid modeling method of a sandwich structure according to claim 3, characterized in that: The method for determining the found hexahedral unit in step S3 includes: The search node is taken as node G1, the non-boundary node adjacent to node G1 on the two-dimensional grid surface is taken as node G2, and the node in the stretching direction of node G2 is taken as G3; Calculate the direction vector obtained by cross-producting the vector from node G1 to node G2 and the vector from node G2 to node G3. When nodes G1, G2, and G3 have nodes along the direction vector pointing to them, two hexahedral units are found; when nodes G1, G2, and G3 have no nodes along the direction vector pointing to them, one hexahedral unit is found.

5. The finite element model rapid modeling method of a sandwich structure according to claim 4, characterized in that: The method for determining the hexahedral unit that meets the preset direction condition includes: setting the nodes pointed to by the direction vectors of nodes G1, G2 and G3 as nodes G4, G5 and G6 respectively; The hexahedral units where the nodes G1, G2, G3, G4, G5, and G6 are located are hexahedral units that meet the preset direction conditions.

6. The finite element model rapid modeling method of a sandwich structure according to claim 5, characterized in that: The first type of operation includes: generating a pentahedron from nodes G1, G2, G3, G4, G5, and G6.

7. The finite element model rapid modeling method of a sandwich structure according to claim 5, characterized in that: The second type of operation includes: removing the pentahedron generated by the previous node search from node G6, and generating a tetrahedron through nodes G1, G2, G3, G4, and G5.

8. A finite element model rapid modeling module for sandwich structures, characterized in that: include: Initial model building module: used to generate a three-dimensional model. The three-dimensional model is obtained by stretching a two-dimensional mesh surface. The three-dimensional model has hexahedral units. Each rectangular mesh of the two-dimensional mesh surface is stretched to obtain a hexahedral unit. Search node module: used to obtain the boundary node set of the two-dimensional grid surface, and the first boundary node in the boundary node set is used as the search node; Operation module: used to find out the hexahedral unit corresponding to the search node that meets the preset direction condition, when there are two hexahedral units found, determine the hexahedral unit that meets the preset direction condition, and perform the first type of operation on the hexahedral unit, and when there is only one hexahedral unit found, perform the second type of operation on the hexahedral unit; Jump module: used to delete the search node in the boundary node set, and use the next boundary node in the boundary node set as the search node, and input it into the operation module until the boundary node set is an empty set; Output module: output the 3D model after operation.

9. The finite element model rapid modeling module of the sandwich structure according to claim 8, characterized in that: Also includes: Judgment module: Node label generation unit: the search node is taken as node G1, the non-boundary node adjacent to node G1 and located on the two-dimensional grid surface is taken as node G2, and the node of node G2 in the stretching direction is taken as G3; Calculation unit: used to calculate the direction vector obtained by cross-producting the vector from node G1 to node G2 and the vector from node G2 to node G3. Judgment unit: when nodes G1, G2 and G3 point to nodes along the direction vector, two hexahedral units are output; when nodes G1, G2 and G3 point to no nodes along the direction vector, one hexahedral unit is output.

10. The finite element model rapid modeling method of a sandwich structure according to claim 9, characterized in that: Judgment module: also includes: A node label generating unit: used for setting the nodes pointed to by the node G1, the node G2 and the node G3 along the direction vector as the node G4, the node G5 and the node G6 respectively; Determine the unit: determine whether the hexahedral unit where the node G1, the node G2, the node G3, the node G4, the node G5, and the node G6 are located is a hexahedral unit that meets the preset direction conditions.

11. The finite element model rapid modeling method of a sandwich structure according to claim 5, characterized in that: The pentahedron generating unit is used to generate a pentahedron from the nodes G1, G2, G3, G4, G5 and G6.

12. The finite element model rapid modeling method of a sandwich structure according to claim 5, characterized in that: Tetrahedron generation unit: used to remove the pentahedron generated by the previous search node to node G6, and generate a tetrahedron through nodes G1, node G2, node G3, node G4, and node G5.

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