Interpolation point extraction method and system and hot spot stress calculation method and system

Abstract

The present invention discloses an interpolation point extraction method and system, as well as a hotspot stress calculation method and system. The method comprises first marking two interpolation lines parallel to the weld toe line in the three-dimensional model of the weld joint, then performing grid discretization processing on the three-dimensional model of the weld joint, and performing finite element analysis on the three-dimensional model of the weld joint to obtain stress data of each interpolation surface node. According to the relative position relationship between the interpolation surface nodes and the hotspot nodes, the interpolation points corresponding to each hotspot node are selected. According to the stress data of the interpolation points corresponding to each hotspot node, the hotspot stress of the hotspot node is calculated using the extrapolation interpolation method. In this way, a large number of interpolation points corresponding to hotspot nodes can be automatically and quickly extracted in batches, which not only reduces the manual operation process and improves the extraction efficiency of hotspot stress. In addition, the number of hotspot nodes used for fatigue assessment of weld joints is increased, thereby ensuring the design reliability of weld joints.

Description

Technical Field

[0001] The present invention relates to the technical field of using the finite element method for auxiliary design, and in particular to an interpolation point extraction method and system, and a hot spot stress calculation method and system. Background Art

[0002] The design and development of large wind turbines requires simulation of key components. In recent years, with the rapid development of computer technology, finite element analysis (FEA) has been increasingly used in the design and development of wind turbines.

[0003] Among them, fatigue strength analysis of complex welded joints is mainly carried out by combining finite element simulation with hot spot stress method. The calculation process is mainly divided into the following steps:

[0004] First, the stress distribution of the weld joint is calculated using the finite element method. Then, empirically select hotspot nodes on the weld toe line where fatigue damage is likely to be greater, or use commercial fatigue analysis software to screen out hotspot nodes on the weld toe line with greater fatigue damage. Next, manually establish a rectangular coordinate system for each hotspot node in the finite element software, with the origin located at the hotspot node, the x- or y-axis in the direction normal to the hotspot node, and the z-axis perpendicular to the parent material surface. Using the rectangular coordinate system established at each hotspot node as a reference, extract the stress results at each interpolation node in the direction normal to the hotspot node. Finally, calculate the stress at the hotspot node using the hotspot stress extrapolation formula. The calculated hotspot stress is then combined with the fatigue load and the weld joint SN curve for fatigue calculation.

[0005] Because hotspot node locations are selected empirically or screened using fatigue calculation software, the complexity of hotspot extrapolation and interpolation limits the selection of stresses to a small number of nodes. Consequently, there's a risk of missing hotspot nodes with the highest actual fatigue damage values, posing a safety risk. Furthermore, engineers manually establish a rectangular coordinate system for extracting stresses from interpolated nodes, targeting hotspot nodes on the weld toe line. This is inefficient and prone to errors. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention proposes a method and system for extracting interpolation points, as well as a method and system for calculating hotspot stress. These methods can quickly and easily extract the interpolation points needed to calculate the hotspot stress at each hotspot node on the weld toe line of a weld joint. The specific technical solution is as follows:

[0007] In a first aspect, a method for extracting interpolation points is provided, comprising:

[0008] Mark at least two interpolation lines parallel to the weld toe line on the base material surface of the three-dimensional model of the weld joint;

[0009] Performing mesh discretization processing on the three-dimensional model of the weld joint to determine all hot spots on the weld toe line and all interpolation surface nodes between two interpolation lines;

[0010] According to the relative positional relationship between the interpolation surface nodes and the hotspot nodes, the interpolation points corresponding to the hotspot nodes are selected from all the interpolation surface nodes.

[0011] In combination with the first aspect, in a first implementable manner of the first aspect, all the interpolation lines are distributed in order from near to far within a region closest to the weld toe line.

[0012] In combination with the first aspect, in a second possible implementation of the first aspect, the grid between the weld toe line and the interpolation line, and the grid between two adjacent interpolation lines are both regular hexahedral grids.

[0013] In combination with the first aspect, in a third implementation manner of the first aspect, an angle between the grid height direction of the hotspot node and the interpolation surface node and the theoretical external normal direction of the weld toe line is less than a preset threshold.

[0014] In combination with the first aspect, in a fourth implementation manner of the first aspect, selecting the interpolation point corresponding to the hotspot node from all the interpolation surface nodes includes:

[0015] Filter out the nearest nodes to the hotspot node from all interpolation surface nodes, and all corner nodes of all meshes containing the hotspot node;

[0016] Taking the hotspot node as the vertex, calculate the angles between different corner nodes and the hotspot node and the nearest node, and select candidate nodes from all filtered corner nodes based on the calculation results;

[0017] Taking the hotspot node as the vertex, calculate the angle between the hotspot node and any two candidate nodes, and select the quadrant calibration point from all selected candidate nodes based on the calculation results;

[0018] Constructing a reference rectangular coordinate system with the hotspot node as the origin based on the quadrant calibration points, the nearest node and the hotspot node;

[0019] The interpolation points corresponding to the hotspot nodes are extracted through the reference rectangular coordinate system.

[0020] In a second aspect, a hot spot stress calculation method is provided, comprising:

[0021] Adopting any one of the interpolation point extraction methods in the first aspect or the first to fourth possible implementations of the first aspect to batch extract interpolation points corresponding to each hotspot node;

[0022] By performing finite element solution on the three-dimensional model of the weld joint, stress data corresponding to all the interpolation surface nodes are obtained;

[0023] Based on the stress data of the interpolation points corresponding to the hotspot nodes, the hotspot stress corresponding to each hotspot node on the weld toe line is calculated using the extrapolation interpolation method.

[0024] In a third aspect, an interpolation point extraction system is provided, comprising:

[0025] an interpolation line construction module configured to mark at least two interpolation lines parallel to the weld toe line on a parent material surface of the three-dimensional model of the weld joint;

[0026] a grid processing module configured to perform grid discretization processing on the three-dimensional model of the weld joint to determine all hotspot nodes on the weld toe line and all interpolation surface nodes between two interpolation lines;

[0027] The interpolation point selection module is configured to select interpolation points corresponding to each hotspot node from all the interpolation surface nodes according to the relative position relationship between the interpolation surface nodes and the hotspot nodes.

[0028] In combination with the third aspect, in a first implementable manner of the third aspect, the interpolation line construction module uses the weld toe line as a reference and marks the interpolation lines on the surface of the base material in order from near to far.

[0029] In combination with the third aspect, in a second implementation manner of the third aspect, the grid processing module divides the grid between the weld toe line and the interpolation line, and the grid between two adjacent interpolation lines into regular hexahedral grids.

[0030] In combination with the third aspect, in a third possible implementation of the third aspect, when performing grid discretization processing, the grid processing module sets the angle between the grid height direction of the hotspot node and the interpolation surface node and the theoretical external normal direction of the weld toe line to be less than a preset threshold.

[0031] In combination with the third aspect, in a fourth implementation manner of the third aspect, the interpolation point selection module includes:

[0032] a node screening unit configured to screen out, from all interpolation surface nodes, the nearest node closest to the hotspot node and all corner nodes of all grids containing the hotspot node;

[0033] The candidate node selection unit is configured to use the hotspot node as a vertex, calculate the angles between different corner nodes and the hotspot node and the nearest node, and select a candidate node from all the selected corner nodes based on the calculation results;

[0034] The calibration point selection unit is configured to use the hotspot node as a vertex, calculate the angle between the hotspot node and any two candidate nodes, and select a quadrant calibration point from all selected candidate nodes according to the calculation result;

[0035] A coordinate system construction unit is configured to construct a reference rectangular coordinate system with the hotspot node as the origin based on the quadrant calibration point, the nearest node and the hotspot node;

[0036] The interpolation point extraction unit is configured to extract the interpolation point corresponding to the hotspot node through the reference rectangular coordinate system.

[0037] In a fourth aspect, a hot spot stress calculation device is provided, comprising:

[0038] The interpolation point extraction system according to any one of the first to fourth implementations of the third aspect;

[0039] A finite element solution system is configured to obtain stress data corresponding to all nodes of the interpolation surface by performing finite element solution on the three-dimensional model of the weld joint;

[0040] The stress calculation system is configured to calculate the hotspot stress corresponding to each hotspot node on the weld toe line using an extrapolation interpolation method based on the stress data of the interpolation points corresponding to each hotspot node extracted by the interpolation point extraction system.

[0041] Beneficial Effects: The interpolation point extraction method and system, as well as the hotspot stress calculation method and system of the present invention, can automatically and rapidly batch extract interpolation points corresponding to a large number of hotspot nodes, reducing manual operations and improving the efficiency of hotspot stress extraction. Furthermore, the number of hotspot nodes used for fatigue assessment of welded joints is increased, ensuring the design reliability of welded joints. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the specific embodiments of the present invention, the following briefly introduces the drawings required for use in the specific embodiments. In all the drawings, each element or part is not necessarily drawn according to the actual scale.

[0043] Figure 1 A flowchart of an interpolation point extraction method provided by an embodiment of the present invention;

[0044] Figure 2 A flow chart of a method for selecting interpolation points provided in one embodiment of the present invention;

[0045] Figure 3 A flow chart of a hot spot stress calculation method provided in one embodiment of the present invention;

[0046] Figure 4 A system block diagram of an interpolation point extraction system provided by an embodiment of the present invention;

[0047] Figure 5 A block diagram of the principle of a hot spot stress calculation device provided by one embodiment of the present invention;

[0048] Figure 6 is a schematic diagram of the marking of the interpolation line;

[0049] Figure 7 Schematic diagram of mesh model for mesh discretization of three-dimensional model of welded joint;

[0050] Figure 8 Schematic diagram of the selected nearest node, candidate nodes and quadrant calibration points;

[0051] Figure 9 Schematic diagram of the reference rectangular coordinate system corresponding to the constructed hotspot nodes. DETAILED DESCRIPTION

[0052] The following embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0053] It should be understood that the technical solutions of the embodiments of this application utilize the hotspot stress extrapolation algorithm described in the Recommendations for Fatigue Design of Welded Joints and Components (hereinafter referred to as the "Specification") to calculate the hotspot stresses at each hotspot node on the weld toe line of the welded joint. In the initial stages of the calculation, the interpolation point extraction method provided in this embodiment can be used to batch extract interpolation points corresponding to each of the hotspot nodes, providing a basis for calculating the hotspot stresses at each hotspot node. The interpolation point extraction method is as follows:

[0054] like Figure 1 The flowchart of the interpolation point extraction method shown in FIG. 1 includes:

[0055] Step 1: Mark at least two interpolation lines parallel to the weld toe line on the base material surface of the three-dimensional model of the weld joint;

[0056] Step 2: performing mesh discretization processing on the three-dimensional model of the weld joint to determine all hot spots on the weld toe line and all interpolation surface nodes between two interpolation lines;

[0057] Step 3: According to the relative position relationship between the interpolation surface nodes and the hotspot nodes, the interpolation points corresponding to the hotspot nodes are selected from all the interpolation surface nodes.

[0058] Specifically, first, the surface of the parent material in the three-dimensional model of the weld joint can be processed by finite element software to plan the imprint line on the surface of the parent material. Figure 6 The two interpolation lines shown are parallel to the weld toe line. The surface of the base material between the two interpolation lines can be defined as the interpolation surface. Then, by performing mesh discretization on the three-dimensional model of the weld joint, multiple mesh nodes are constructed on the surface of the base material, such as Figure 7 As shown in the figure, mesh nodes located on the weld toe line are hotspot nodes, and mesh nodes located in the interpolation surface area are interpolation surface nodes. This allows the finite element software to automatically select a large number of hotspot nodes, reducing manual labor and increasing the number of hotspot nodes used for fatigue assessment of welded joints, thereby ensuring the design reliability of welded joints. Finally, based on the relative positional relationship between the interpolation surface nodes and the hotspot nodes, the same extraction method can be used to sequentially select the interpolation points corresponding to each hotspot node from the numerous interpolation surface nodes.

[0059] In this embodiment, all interpolation lines are optionally distributed in order from near to far within the region closest to the weld toe line. Specifically, the arrangement of the weld toe lines can be determined in accordance with specification requirements. Two interpolation lines are marked on the surface of the base material in the region closest to the weld toe line. These two interpolation lines can be distributed from the inside to the outside around the weld toe line.

[0060] In this embodiment, the mesh between the weld toe line and the interpolation line, as well as the mesh between two adjacent interpolation lines, can optionally be a regular hexahedral mesh. Specifically, the specification specifies a hexahedral mesh. Therefore, to ensure computational accuracy, when performing mesh discretization on the three-dimensional weld joint model, it is necessary to ensure that the mesh between the weld toe line and the interpolation line, and between interpolation lines, is a regular hexahedral mesh.

[0061] In this embodiment, the angle between the height direction of the mesh containing the hotspot nodes and the interpolation surface nodes and the theoretical outer normal direction of the weld toe line can optionally be less than a preset threshold. Specifically, when performing mesh discretization on the three-dimensional weld joint model, the angle between the height direction of the mesh containing the hotspot nodes and the interpolation surface nodes and the theoretical outer normal direction of the weld toe line must also be less than a preset threshold. In this embodiment, the preset threshold can be set to ±degtol, where degtol ≤ 5° can be selected based on experience.

[0062] In this embodiment, optionally, selecting an interpolation point corresponding to the hotspot node from all the interpolation surface nodes includes:

[0063] Step 3-1: Filter out the nearest node to the hotspot node from all interpolation surface nodes, as well as all corner nodes of all grids containing the hotspot node;

[0064] Step 3-2: Taking the hotspot node as the vertex, calculate the angles between different corner nodes and the hotspot node and the nearest node, and select candidate nodes from all filtered corner nodes based on the calculation results;

[0065] Step 3-3: Taking the hotspot node as the vertex, calculate the angle between the hotspot node and any two candidate nodes, and select the quadrant calibration point from all selected candidate nodes based on the calculation results;

[0066] Step 3-4: construct a reference rectangular coordinate system with the hotspot node as the origin based on the quadrant calibration point, the nearest node and the hotspot node;

[0067] Step 3-5: extract the interpolation point corresponding to the hotspot node through the reference rectangular coordinate system.

[0068] Specifically, if Figure 2 、 Figure 8 As shown in the figure, when selecting the interpolation point corresponding to the hotspot node, first, each interpolation surface node can be traversed. Based on the position coordinates of each interpolation surface node and the hotspot node, the distance between each interpolation surface node and the hotspot node is calculated, thereby selecting the nearest node A' closest to the hotspot node A from the many interpolation surface nodes. Then, all grids including the hotspot node A are selected from the many grids.

[0069] Then, the angles between the hotspot node A, the nearest node A' and each corner node in the selected grid can be calculated respectively based on the position coordinates of the hotspot node, the corner node and the nearest node A'. In the calculation process, the hotspot node A is used as the vertex. The angles corresponding to the calculated corner nodes are then compared with the preset screening conditions. When the screening conditions are met, the corner nodes corresponding to the angles can be used as candidate nodes. In this embodiment, when the screening conditions can be set to 90°-degtol≤angle≤90°+degtol, the candidate nodes screened out are shown in the figure, where node B', node C', node D', node E', and node F' are all candidate nodes.

[0070] Afterwards, two different candidate nodes are randomly selected from the screened candidate nodes, and the angles between the hotspot node A and the two selected candidate nodes can be calculated respectively according to the position coordinates of the candidate nodes and the hotspot nodes. In the calculation process, the hotspot node A is used as the vertex. The calculated result is then compared with the preset selection conditions. When the calculation result meets the selection conditions, the candidate node corresponding to the calculation result can be used as the quadrant calibration point. If it does not meet the conditions, two different candidate nodes are randomly selected again to continue the calculation. In this embodiment, the selection condition can be set to 180°-degtol≤calculation result≤180°+degtol. The selected quadrant nodes include candidate node B' and candidate node C'.

[0071] Then, with the current hotspot node A as the coordinate origin, A' as the x-axis positive calibration point, and the candidate node B' or candidate node C' as the second quadrant calibration point, a reference rectangular coordinate system Oxyz is established for extracting the interpolation point corresponding to the hotspot node A. The established reference rectangular coordinate system Oxyz is as follows: Figure 9 Finally, using Oxyz as a reference, we can extract interpolation point 1 and interpolation point 2 corresponding to hotspot node A.

[0072] like Figure 3 The flowchart of the hot spot stress calculation method shown in FIG. 1 includes:

[0073] The interpolation point extraction method mentioned above is used to batch extract the interpolation points corresponding to each hotspot node;

[0074] By performing finite element solution on the three-dimensional model of the weld joint, stress data corresponding to all the interpolation surface nodes are obtained;

[0075] Based on the stress data of the interpolation points corresponding to the hotspot nodes, the hotspot stress corresponding to each hotspot node on the weld toe line is calculated using the extrapolation interpolation method.

[0076] Specifically, when calculating the hot spot stress, first, the finite element software can be used to perform finite element analysis on the three-dimensional model of the weld joint after mesh discretization, so as to obtain the stress data corresponding to each interpolation surface node, providing a basis for the subsequent calculation of the hot spot stress corresponding to each of the hot spot nodes. Then, the above-mentioned interpolation point extraction method can be used to select the corresponding interpolation surface nodes from the numerous interpolation surface nodes as the interpolation points for calculating the hot spot stress of the hot spot node. Finally, according to the stress data of the interpolation points corresponding to the interpolation points of each hot spot node, the hot spot stress of the hot spot node is calculated using the existing extrapolation interpolation method. The above-mentioned interpolation point extraction method can automatically and quickly extract the interpolation points corresponding to a large number of hot spot nodes in batches, which not only reduces the manual operation process and improves the efficiency of hot spot stress extraction. It also increases the number of hot spot nodes used for fatigue assessment of welded joints, ensuring the design reliability of welded joints.

[0077] like Figure 4 The system block diagram of the interpolation point extraction system shown in FIG. 1 includes:

[0078] an interpolation line construction module configured to mark at least two interpolation lines parallel to the weld toe line on a parent material surface of the three-dimensional model of the weld joint;

[0079] a grid processing module configured to perform grid discretization processing on the three-dimensional model of the weld joint to determine all hotspot nodes on the weld toe line and all interpolation surface nodes between two interpolation lines;

[0080] The interpolation point selection module is configured to select interpolation points corresponding to each hotspot node from all the interpolation surface nodes according to the relative position relationship between the interpolation surface nodes and the hotspot nodes.

[0081] Specifically, the interpolation line construction module can use the finite element software to process the surface of the parent material in the three-dimensional model of the weld joint, thereby planning the Figure 6 The two interpolation lines shown are parallel to the weld toe line. The surface of the parent material between the two interpolation lines can be defined as an interpolation surface. The grid processing module can construct a plurality of grid nodes on the surface of the parent material by performing grid discretization processing on the three-dimensional model of the weld joint. The grid nodes located on the weld toe line are hotspot nodes, and the grid nodes located in the interpolation surface area are interpolation surface nodes. In this way, a large number of hotspot nodes can be automatically selected through finite element software, which not only reduces manual operations, but also increases the number of hotspot nodes used for fatigue assessment of weld joints, thereby ensuring the design reliability of weld joints. The interpolation point selection module can select the interpolation points corresponding to each of the hotspot nodes from the plurality of interpolation surface nodes in turn using the same extraction method based on the relative position relationship between the interpolation surface nodes and the hotspot nodes.

[0082] In this embodiment, the interpolation line construction module optionally marks the interpolation lines on the parent material surface in descending order, using the weld toe line as a reference. Specifically, the interpolation line construction module may mark two interpolation lines on the parent material surface in the region closest to the weld toe line. These two interpolation lines may be distributed from the inside out around the weld toe line.

[0083] In this embodiment, the mesh processing module optionally divides the mesh between the weld toe line and the interpolation line, as well as the mesh between two adjacent interpolation lines, into regular hexahedral meshes. Specifically, when performing mesh discretization processing on the three-dimensional weld joint model, the mesh processing module can ensure that the mesh between the weld toe line and the interpolation line, and between interpolation lines, is a regular hexahedral mesh.

[0084] In this embodiment, the mesh processing module may optionally set the angle between the height direction of the meshes of the hotspot nodes and the interpolation surface nodes and the theoretical outer normal direction of the weld toe line to be less than a preset threshold when performing mesh discretization processing. Specifically, when performing mesh discretization processing on the three-dimensional weld joint model, the mesh processing module may further set the angle between the height direction of the meshes including the hotspot nodes and the interpolation surface nodes and the theoretical outer normal direction of the weld toe line to be less than a preset threshold.

[0085] In this embodiment, optionally, the interpolation point selection module includes:

[0086] a node screening unit configured to screen out, from all interpolation surface nodes, the nearest node closest to the hotspot node and all corner nodes of all grids containing the hotspot node;

[0087] The candidate node selection unit is configured to use the hotspot node as a vertex, calculate the angles between different corner nodes and the hotspot node and the nearest node, and select a candidate node from all the selected corner nodes based on the calculation results;

[0088] The calibration point selection unit is configured to use the hotspot node as a vertex, calculate the angle between the hotspot node and any two candidate nodes, and select a quadrant calibration point from all selected candidate nodes according to the calculation result;

[0089] A coordinate system construction unit is configured to construct a reference rectangular coordinate system with the hotspot node as the origin based on the quadrant calibration point, the nearest node and the hotspot node;

[0090] The interpolation point extraction unit is configured to extract the interpolation point corresponding to the hotspot node through the reference rectangular coordinate system.

[0091] Specifically, the interpolation point selection module includes a node screening unit, an alternative node selection unit, a calibration point selection unit, a coordinate system construction unit and an interpolation point extraction unit.

[0092] The node screening unit can traverse each interpolation surface node and calculate the distance between each interpolation surface node and the hotspot node based on the position coordinates of each interpolation surface node and the hotspot node, thereby selecting the nearest node A' closest to the hotspot node A from among the many interpolation surface nodes. All grids including the hotspot node A are selected from the many grids. The nearest node and the hotspot node A are removed from the corner nodes of the selected grids, and the remaining corner nodes are all the corner nodes corresponding to the hotspot node A.

[0093] The candidate node selection unit can calculate the angles between the hotspot node A, the closest node A' and each corner node in the selected grid according to the position coordinates of the hotspot node, the corner node and the closest node A'. In the calculation process, the hotspot node A is used as the vertex.

[0094] The candidate node selection unit can compare the calculated angle corresponding to each corner node with a preset screening condition. When the screening condition is met, the corner node corresponding to the angle angle can be selected as a candidate node. In this embodiment, the screening condition can be set to 90°-degtol≤angle≤90°+degtol. The candidate nodes selected are shown in the figure, where nodes B', C', D', E', and F' are all candidate nodes.

[0095] The calibration point selection unit can randomly select two different alternative nodes from all the alternative nodes selected by the alternative node selection unit, and calculate the angle between the hotspot node A and the two alternative nodes based on the position coordinates of the alternative nodes and the hotspot node, with the hotspot node A as the vertex in the calculation process. The calibration point selection unit can compare the calculated result with the preset selection conditions. When the calculation result meets the selection conditions, the alternative node corresponding to the calculation result can be used as the quadrant calibration point. When the calculation result does not meet the selection conditions, the calibration point selection unit reselects two alternative nodes to continue the calculation. In this embodiment, the selection condition can be set to 180°-degtol≤calculation result≤180°+degtol. The selected quadrant nodes include alternative node B' and alternative node C'.

[0096] The coordinate system construction unit can use the hotspot node A as the coordinate origin, A' as the positive calibration point of the x-axis, and the alternative node B' or alternative node C' as the second quadrant calibration point to establish a reference rectangular coordinate system Oxyz for extracting the interpolation point corresponding to the hotspot node A.

[0097] The interpolation point extraction unit can extract interpolation point 1 and interpolation point 2 corresponding to the hotspot node A with reference to Oxyz.

[0098] like Figure 5 The principle block diagram of the hot spot stress calculation device shown in FIG. 1 is a block diagram of the hot spot stress calculation device shown in FIG. 1 , wherein the hot spot stress calculation device comprises:

[0099] The interpolation point extraction system described above;

[0100] A finite element solution system is configured to obtain stress data corresponding to all nodes of the interpolation surface by performing finite element solution on the three-dimensional model of the weld joint;

[0101] The stress calculation system is configured to calculate the hotspot stress corresponding to each hotspot node on the weld toe line using an extrapolation interpolation method based on the stress data of the interpolation points corresponding to each hotspot node extracted by the interpolation point extraction system.

[0102] Specifically, the computing device includes an interpolation point extraction system, a finite element solution system and a stress calculation system.

[0103] The finite element solution system can perform finite element analysis on the three-dimensional model of the welded joint after mesh discretization through finite element software, thereby obtaining the stress data corresponding to each interpolation surface node, providing a basis for the subsequent calculation of the hot spot stress corresponding to each of the hot spot nodes. The interpolation point extraction system can use the above-mentioned interpolation point extraction method to select the corresponding interpolation surface nodes from the numerous interpolation surface nodes as interpolation points for calculating the hot spot stress of the hot spot node. The stress calculation system uses the existing extrapolation interpolation method to calculate the hot spot stress of the hot spot node based on the stress data of the interpolation points corresponding to each hot spot node. The above-mentioned interpolation point extraction method can automatically and quickly extract the interpolation points corresponding to a large number of hot spot nodes in batches, which not only reduces the manual operation process and improves the efficiency of hot spot stress extraction. It also increases the number of hot spot nodes used for fatigue assessment of welded joints, ensuring the design reliability of welded joints.

[0104] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A method for extracting interpolation points, characterized in that: include: Mark at least two interpolation lines parallel to the weld toe line on the base material surface of the three-dimensional model of the weld joint; Performing mesh discretization processing on the three-dimensional model of the weld joint to determine all hotspot nodes on the weld toe line and all interpolation surface nodes between two interpolation lines, wherein the angle between the mesh height direction of the hotspot nodes and the interpolation surface nodes and the theoretical outer normal direction of the weld toe line is less than a preset threshold; According to the relative position relationship between the interpolation surface nodes and the hotspot nodes, the interpolation points corresponding to the hotspot nodes are selected from all the interpolation surface nodes, including: Filter out the nodes closest to the hotspot node from all interpolation surface nodes, as well as all corner nodes of all meshes containing the hotspot node; Taking the hotspot node as the vertex, calculate the angles between different corner nodes and the hotspot node and the nearest node, and compare the angles corresponding to each corner node with the preset filtering conditions. When the filtering conditions are met, the corner node corresponding to the angle can be used as a candidate node. The filtering conditions are set as follows: , is the preset threshold; Taking the hotspot node as the vertex, calculate the angle between the hotspot node and any two candidate nodes, and compare the calculated result with the preset selection conditions. When the calculation result meets the selection conditions, the candidate node corresponding to the calculation result can be used as the quadrant calibration point. The selection conditions are set as follows: ； Constructing a reference rectangular coordinate system with the hotspot node as the origin based on the quadrant calibration points, the nearest node and the hotspot node; Taking the reference rectangular coordinate system established at the hotspot node as a reference, the interpolation points in the normal direction outside the hotspot node are extracted.

2. The interpolation point extraction method according to claim 1, characterized in that: All the interpolation lines are distributed in the area closest to the weld toe line in order from near to far.

3. The interpolation point extraction method according to claim 1, characterized in that: The grid between the weld toe line and the interpolation line, and the grid between two adjacent interpolation lines are all regular hexahedral grids.

4. A hot spot stress calculation method, characterized in that: include: Adopting the interpolation point extraction method according to any one of claims 1 to 3 to batch extract the interpolation points corresponding to each hotspot node; By performing finite element solution on the three-dimensional model of the weld joint, stress data corresponding to all the interpolation surface nodes are obtained; Based on the stress data of the interpolation points corresponding to the hotspot nodes, the hotspot stress corresponding to each hotspot node on the weld toe line is calculated using the extrapolation interpolation method.

5. An interpolation point extraction system, characterized in that: include: an interpolation line construction module configured to mark at least two interpolation lines parallel to the weld toe line on a parent material surface of the three-dimensional model of the weld joint; a grid processing module configured to perform grid discretization processing on the three-dimensional model of the weld joint to determine all hotspot nodes on the weld toe line and all interpolation surface nodes between two interpolation lines; The grid processing module sets the angle between the grid height direction of the hotspot node and the interpolation surface node and the theoretical outer normal direction of the weld toe line to be less than a preset threshold when performing grid discretization processing; An interpolation point selection module is configured to select interpolation points corresponding to each hotspot node from all interpolation surface nodes according to the relative position relationship between the interpolation surface nodes and the hotspot nodes. The interpolation point selection module includes: a node screening unit configured to screen out, from all interpolation surface nodes, the nearest node closest to the hotspot node and all corner nodes of all grids containing the hotspot node; The candidate node selection unit is configured to use the hotspot node as the vertex, calculate the angles between different corner nodes and the hotspot node and the nearest node, and compare the angles corresponding to each corner node calculated with the preset screening conditions. When the screening conditions are met, the corner node corresponding to the angle can be used as a candidate node. The screening conditions are set as follows: , is the preset threshold; The calibration point selection unit is configured to use the hotspot node as the vertex, calculate the angle between the hotspot node and any two candidate nodes, and compare the calculated result with the preset selection conditions. When the calculation result meets the selection conditions, the candidate node corresponding to the calculation result can be used as the quadrant calibration point. The selection conditions are set as follows: ； A coordinate system construction unit is configured to construct a reference rectangular coordinate system with the hotspot node as the origin based on the quadrant calibration point, the nearest node and the hotspot node; The interpolation point extraction unit is configured to extract interpolation points in the normal direction outside the hotspot node with reference to the reference rectangular coordinate system established at the hotspot node.

6. The interpolation point extraction system according to claim 5, characterized in that: The interpolation line construction module uses the weld toe line as a reference and marks the interpolation lines on the surface of the base material in order from near to far.

7. The interpolation point extraction system according to claim 5, characterized in that: The grid processing module divides the grid between the weld toe line and the interpolation line, and the grid between two adjacent interpolation lines into regular hexahedral grids.

8. A hot spot stress calculation device, characterized in that: include: The interpolation point extraction system according to any one of claims 5 to 7; A finite element solution system is configured to obtain stress data corresponding to all nodes of the interpolation surface by performing finite element solution on the three-dimensional model of the weld joint; The stress calculation system is configured to calculate the hotspot stress corresponding to each hotspot node on the weld toe line using an extrapolation interpolation method based on the stress data of the interpolation points corresponding to each hotspot node extracted by the interpolation point extraction system.

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