LNG storage tank piled raft foundation high-quality grid automatic division method
By automatically dividing the grid of the pile raft foundation of large LNG storage tanks in the ABAQUS model and establishing coupling constraints between pile top nodes and raft plate nodes, the problem of low efficiency in generation and coupling operation at the junction of pile raft foundations in the prior art is solved, and the accuracy of high-quality grid division and analysis results is achieved.
Patent Information
- Application Number
- CN202510083212.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-20
- Publication Date
- 2025-05-13
AI Technical Summary
In finite element analysis, the prior art is difficult to accurately generate grid nodes at the pile-raft foundation junction of large liquefied natural gas (LNG) storage tanks, resulting in difficulty in extracting internal forces, and manual coupling operation is inefficient and prone to human errors.
A high-quality grid automatic division method for pile raft foundation of LNG storage tank piles and raft foundation is proposed. By defining a set containing all pile top nodes in the ABAQUS model, the part that intersects the raft foundation and the pile foundation is divided into independent entities, and the grid is divided within and outside the pile foundation, and the coupling constraint between the pile top node and the raft node is automatically established.
It realizes the accurate arrangement of grid nodes at the junction of pile body and raft slab, automates the establishment of grid division and coupling constraints, improves the accuracy and work efficiency of finite element analysis, and reduces the possibility of human error.
Smart Images
Figure CN119989802A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of finite element analysis and relates to a high-quality automatic grid division method for a pile raft foundation of a large liquefied natural gas (LNG) storage tank. Background Art
[0002] Large LNG storage tanks usually use pile raft foundations. In finite element analysis, pile foundations are usually simulated using beam units, while raft foundations are simulated using solid units. Directly dividing the raft entity in ABAQUS cannot accurately generate mesh nodes at the junction of the raft and the pile body, which makes it difficult to extract the internal forces at the junction after the calculation is completed. In addition, due to different unit types, the end nodes of the beam unit simulating the pile need to be coupled with the nodes of the three-dimensional solid unit of the raft. Due to the large number of piles, manual work is used, which results in too many repeated operations, low efficiency, and prone to human errors. How to accurately generate mesh nodes at the junction of the pile body and the raft, and automatically establish coupling constraints between the pile end nodes and the corresponding areas on the raft, is very important for improving the accuracy of the simulation results of the pile raft foundation of LNG storage tanks. Summary of the invention
[0003] In order to solve the problems existing in the background technology, the present invention proposes a high-quality automatic meshing method for LNG tank pile raft foundation. The method aims to improve the accuracy and automation of meshing, and can automatically establish coupling constraints between pile top nodes and raft unit nodes.
[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A high-quality automatic mesh generation method for LNG tank pile raft foundation includes: Step 1: Define a set that includes and only includes all pile top nodes in the ABAQUS model where the raft object and pile foundation object have been established; Step 2: Divide the intersection of the raft foundation and the pile foundations into independent entities; Step 3: Divide the raft slab into grids within the pile foundation area; Step 4: Mesh the raft slab outside the pile foundation area; Step 5: Establish coupling constraints between pile top node and raft slab.
[0005] Furthermore, in the step 1, the pile foundation is simulated by line elements, and the raft is simulated by three-dimensional solid elements.
[0006] Furthermore, the intersection with each pile foundation in step 2 is the intersection with an actual three-dimensional pile foundation object.
[0007] Furthermore, the specific method of dividing the intersection of the raft foundation and the pile foundations into independent entities in step 2 is: Traverse the set of pile top nodes of the pile foundation, take out a pile top node each time, and get its three-dimensional coordinates according to the coordinates attribute of the node object, based on the above-obtained coordinates and the known pile foundation diameter data Draw a circle for segmentation on the bottom surface of the raft solid; Using components Methods: A circular area bordering the pile foundation is segmented on the bottom surface of the raft; The generated region boundary is used to divide the raft solid into the part within the pile foundation range and the part outside the pile foundation range.
[0008] Furthermore, the sketch object The method is completed. The input parameters of the function are the coordinates of the center of the circle and the coordinates of a point on the circumference. The coordinates of the center of the circle are the coordinates of the pile top node. The coordinates of a point on the circumference are calculated by translating the coordinates of the center of the circle along a coordinate axis in the plane where the circle is located by 0.5 times the diameter of the pile foundation.
[0009] Furthermore, the specific method of performing regional grid division within the pile foundation range in step 3 is: S301, select any cylindrical area within the pile foundation range divided in step 2, and divide it into four 90-degree fan-shaped columns; S302, selecting all edges of the bottom or top surface of the cylindrical region and specifying a seed size for them; S303, meshing the cylindrical region using a structured meshing method; S304, traverse all other cylindrical areas within the divided pile foundation range, and divide them into grids in sequence according to the above S301 to S303.
[0010] Furthermore, select all edges of the bottom or top of the cylindrical region and specify the seed size.
[0011] Furthermore, the specific method of performing grid division on the raft slab outside the pile foundation range in step 4 is: Select the edge that forms the outer contour of the raft on the bottom or top surface of the raft and specify the seed size for it; The sweep method is used to divide the mesh into areas outside the pile foundation.
[0012] Furthermore, the specific method of establishing the coupling constraint between the pile top node of the pile foundation and the raft slab in step 5 is: S501, select a node from the set of pile top nodes, create Region 1, and use the coordinates attribute of the node to obtain the coordinates of the point; S502, using the pile top node coordinates and pile foundation diameter data, select all nodes on the raft that need to be coupled with this node, and define them as Region 2; S503, create Region 1 and Region 2 Coupling constraints; S504 , traverse the remaining pile top nodes, and establish coupling constraints corresponding to the remaining pile top nodes in sequence according to S501 to S503 .
[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Accurately arrange the grid nodes at the junction of the pile body and the raft to facilitate the extraction of the internal force at this point after the calculation is completed; 2. Automatically realize the structured grid division of the pile-raft interface area; 3. Automatically establish the coupling constraints of the pile top node and the raft node, reducing the chance of human operation errors and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 is a flow chart of the method of the present invention; Figure 2 It is the ABAQUS model of the raft object and the pile foundation object created by the present invention; Figure 3 is a collection of pile top nodes of the present invention; Figure 4 It is the way to divide the area where the raft bottom surface meets the pile foundation; Figure 5 It is a schematic diagram of the grid division of the raft within the scope of the pile foundation; Figure 6 This is a schematic diagram of the mesh division of the raft slab outside the pile foundation area; Figure 7 Created for Region 1 and Region 2 Schematic diagram of coupling constraints; Figure 8 It is a schematic diagram of the coupling constraints corresponding to the remaining pile top nodes. DETAILED DESCRIPTION
[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0016] The purpose of the present invention is to provide a high-quality automatic mesh generation method for LNG storage tank pile raft foundation, and through secondary development of ABAQUS, the high-quality mesh generation can be automatically realized in the finite element model of the raft foundation, and the coupling constraints between the pile top and the raft node can be automatically established.
[0017] like Figure 1 As shown, the technical solution adopted by the present invention is as follows: a method for automatically dividing a high-quality grid of a pile raft foundation of an LNG storage tank, comprising: Step 1: Define a set that includes and only includes all pile top nodes in the ABAQUS model where the raft object and pile foundation object have been established; Step 2: Divide the intersection of the raft foundation and the pile foundations into independent entities; Step 3: Mesh the area within the pile foundation of the raft slab; Step 4: Mesh the raft slab outside the pile foundation area; Step 5: Establish coupling constraints between pile top node and raft slab.
[0018] like Figure 2 As shown, a set Set-PileTopNodes containing and only containing all pile top nodes is defined in the ABAQUS model of the completed raft object and pile foundation object. In this example, the raft has a diameter of 78.4m and a thickness of 1.2m. The center coordinates of the raft bottom are (0,0,0), and the raft is supported by 328 circular concrete piles underneath.
[0019] like Figure 3 As shown in the figure, to facilitate the selection of all pile top nodes, hide the raft entity, set the view to side view, and set the view projection mode to PARALLEL. In the model, the pile foundation is simulated by line elements, and the raft is simulated by three-dimensional solid elements.
[0020] The intersection of the raft foundation and the pile foundations is divided into independent entities. The intersection with the pile foundations refers to the intersection with the actual three-dimensional pile foundation objects, rather than the line elements used in the finite element model.
[0021] S201, separating the area where the raft bottom surface and the pile foundation meet.
[0022] like Figure 4 As shown, first ensure that the raft entity is an independent entity, otherwise it should be converted into an independent entity using the Make Independent function. Traverse the set of pile top nodes Set-PileTopNodes, take out a pile top node each time, and obtain its three-dimensional coordinates (x, y, z) according to the coordinates attribute of the node object. Based on the above coordinates and the known pile foundation diameter Draw a circle on the bottom surface of the raft solid for segmentation. This step uses the sketch object The method is completed, where the input parameters of the function are the coordinates of the center of the circle and the coordinates of a point on the circumference. What needs to be input here is the two-dimensional coordinates, and the z coordinate of the node can be omitted. The coordinates of the center of the circle are the coordinates of the pile top node (x, y, z) minus the z coordinate, that is, (x, y). The coordinates of a point on the circumference can be calculated by translating the coordinates of the center of the circle along a coordinate axis in the plane where the circle is located by 0.5 times the diameter of the pile foundation. Assuming the x-axis is translated, the coordinates of a point on the circumference are (x+0.5 ,y). Methods The plane area that interfaces with the pile foundation is segmented on the bottom surface of the raft slab, and the interface area consists of 328 separate circular sub-areas.
[0023] S202, using the regional boundary generated in S201, the raft slab entity is divided into a part within the pile foundation range and a part outside the pile foundation range. The method is complete.
[0024] Step 3: Divide the grid of the raft area within the pile foundation.
[0025] like Figure 5 As shown, the specific method of step three is: S301, select any area within the pile foundation range divided in step 2, and divide it into four 90-degree fan-shaped columns.
[0026] S302, select all edges of the bottom or top surface of the cylindrical area, and specify a seed size or a seed quantity for them. In this example, the seed size is specified to be 0.25m.
[0027] S303: Grid the area using a structured grid division method.
[0028] S304, traverse all other divided areas within the pile foundation range, and divide them into grids in sequence according to the above S301 to S303, and obtain a total of 52480 grids.
[0029] Step 4: Grid the area outside the raft pile foundation. Figure 6 As shown, in the secondary development The function selects this area and specifies the edge seed size for the outer circumference of the raft. In this example, 0.25m is used. The Sweep method is used for meshing, and a total of 420,330 meshes are obtained. The mesh nodes are accurately arranged at the junction of the pile foundation and the raft.
[0030] After completing the meshing of the area within the pile foundation range and the meshing of the raft slab outside the pile foundation range, the coupling constraints of the pile top node and the raft slab are established.
[0031] S501, select any node from the set of pile top nodes, create Region 1, and use the coordinates attribute of the node to obtain the coordinates (x, y, z) of the point.
[0032] S502, using the pile top node coordinates (x, y, z) and the pile foundation diameter Select all nodes on the raft that need to be coupled with this node and define them as Region 2. Select the raft nodes using the function Conduct. It is used to establish a cylinder containing the node to be selected. This value can be determined according to the unit division size. In this example, it is taken as 0.01.
[0033] S503, such as Figure 7 As shown, create the above Region 1 and Region 2 Coupling constraints, this step is done by The method is complete.
[0034] S504, such as Figure 8 As shown, traverse the remaining pile top nodes and establish corresponding coupling constraints in sequence according to the above steps 1-3.
[0035] Thus, the present invention realizes the automatic division of high-quality grids for the pile raft foundation of the LNG storage tank.
[0036] The above is an exemplary description of the present invention. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or they are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.
[0037] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A high-quality automatic grid generation method for LNG storage tank pile raft foundation, characterized in that: Included are: Step 1: Define a set that includes and only includes all pile top nodes in the ABAQUS model where the raft object and pile foundation object have been established; Step 2: Divide the intersection of the raft foundation and the pile foundations into independent entities; Step 3: Mesh the area within the pile foundation of the raft slab; Step 4: Mesh the raft slab outside the pile foundation area; Step 5: Establish coupling constraints between pile top node and raft slab.
2. The method for automatically dividing high-quality meshes of a piled raft foundation of an LNG storage tank according to claim 1 is characterized in that: In the step 1, the pile foundation is simulated by line elements, and the raft is simulated by three-dimensional solid elements.
3. The method for automatically dividing high-quality meshes of a piled raft foundation of an LNG storage tank according to claim 1 is characterized in that: The intersection with each pile foundation in step 2 is the intersection with the actual three-dimensional pile foundation object.
4. The method for automatically dividing high-quality meshes of a piled raft foundation of an LNG storage tank according to claim 1 is characterized in that: The specific method of dividing the intersection of the raft foundation and the pile foundations into independent entities in step 2 is: Traverse the set of pile top nodes of the pile foundation, take out a pile top node each time, and get its three-dimensional coordinates according to the coordinates attribute of the node object, based on the above-obtained coordinates and the known pile foundation diameter data Draw a circle for segmentation on the bottom surface of the raft solid; Using components Methods: A circular area bordering the pile foundation is segmented on the bottom surface of the raft; The generated region boundary is used to divide the raft solid into the part within the pile foundation range and the part outside the pile foundation range.
5. The method for automatically dividing high-quality meshes of LNG tank pile raft foundation according to claim 4 is characterized in that: Using sketch objects The method is completed. The input parameters of the function are the coordinates of the center of the circle and the coordinates of a point on the circumference. The coordinates of the center of the circle are the coordinates of the pile top node. The coordinates of a point on the circumference are calculated by translating the coordinates of the center of the circle along a coordinate axis in the plane where the circle is located by 0.5 times the diameter of the pile foundation.
6. The method for automatically dividing high-quality meshes of a piled raft foundation of an LNG storage tank according to claim 1 is characterized in that: The specific method of performing regional grid division within the pile foundation range in step 3 is: S301, select any cylindrical area within the pile foundation range divided in step 2, and divide it into four 90-degree fan-shaped columns; S302, selecting all edges of the bottom or top surface of the cylindrical region and specifying a seed size for them; S303, meshing the cylindrical region using a structured meshing method; S304, traverse all other cylindrical areas within the divided pile foundation range, and divide them into grids in sequence according to the above S301 to S303.
7. The method for automatically dividing high-quality meshes of LNG tank pile raft foundation according to claim 6 is characterized in that: Select all edges of the bottom or top of the cylindrical region and specify a seed size.
8. The method for automatically dividing high-quality meshes of a piled raft foundation of an LNG storage tank according to claim 1 is characterized in that: The specific method of meshing the area outside the pile foundation range of the raft slab in step 4 is: Select the edge that forms the outer contour of the raft on the bottom or top surface of the raft and specify the seed size for it; The sweep method is used to divide the mesh into areas outside the pile foundation.
9. The method for automatically dividing high-quality meshes of LNG tank pile raft foundation according to claim 1 is characterized in that: The specific method of establishing the coupling constraint between the pile top node of the pile foundation and the raft slab in step 5 is: S501, select a node from the set of pile top nodes, create Region 1, and use the coordinates attribute of the node to obtain the coordinates of the point; S502, using the pile top node coordinates and pile foundation diameter data, select all nodes on the raft that need to be coupled with this node, and define them as Region 2; S503, create Region 1 and Region 2 Coupling constraints; S504 , traverse the remaining pile top nodes, and establish coupling constraints corresponding to the remaining pile top nodes in sequence according to S501 to S503 .