Earth and rockfill dam finite element calculation two-dimensional grid generation method and system oriented to rock foundation grid number optimization

Abstract

The invention discloses an earth and rockfill dam finite element calculation two-dimensional grid generation method and system oriented to rock foundation grid number optimization, and the method comprises the steps: carrying out the region definition of the maximum section of an earth and rockfill dam, setting related parameters, and carrying out the horizontal layering division and vertical striping division of different regions, wherein the starting point and the end point of each horizontal line are related to the hierarchy of the horizontal lines, and the starting point and the end point of each vertical line are related to the strip level of the vertical lines, then carrying out independent grid identification on all block areas, and optimizing the grids of the dam body frame selection area; all the five-node transition grids of each area are split into three-node grids, and the three-node grids are combined with the grids of the dam body frame selection area to obtain a finite element calculation two-dimensional grid of the maximum section of the earth and rockfill dam. According to the method, accurate grid division of the maximum section of the earth and rockfill dam is achieved, the number of grids of a rock foundation is optimized, the precision and efficiency of two-dimensional finite element analysis and calculation of the earth and rockfill dam are effectively improved, and the method has important engineering application value.

Description

Technical Field

[0001] The present application relates to the field of finite element calculation of water conservancy projects, and in particular to a two-dimensional grid generation method and system for finite element calculation of earth-rock dams aimed at optimizing the number of rock foundation grids. Background Art

[0002] During the design and construction of earth-rock dams, stress and deformation analysis is an important means to ensure the safe operation of earth-rock dam projects. Although the finite element method has been widely used as a powerful tool for analyzing engineering problems, in the process of meshing the two-dimensional geological finite element model, it is necessary to consider the geometric irregularities and mesh transition problems caused by material inhomogeneity at the same time in order to balance the calculation accuracy and efficiency. The existing finite element pre-processing software does not have special technical means for this application scenario, and manual optimization and adjustment are required during processing, which is time-consuming and has high technical barriers.

[0003] The geometry and material properties of earth-rock dams are complex and varied, and traditional mesh generation methods are difficult to adapt to this complexity. Especially on rock foundations, how to optimize the number of meshes to improve computational efficiency and accuracy is a technical challenge. Existing mesh generation methods often require a lot of manual intervention, and the quality of the generated meshes varies.

[0004] In finite element analysis, the density of the grid directly affects the accuracy and efficiency of the calculation. In areas that require precise calculations, such as stress concentration and large deformation areas, small-scale grid elements are used, while in areas that do not require precise calculations, large-scale grid elements can be used. However, how to reasonably divide the grid and estimate the areas that do and do not require precise calculations is highly dependent on the engineer's processing experience.

[0005] With the continuous development of CAE simulation technology, how to balance computational efficiency and accuracy has become an urgent problem to be solved. Meshing is one of the key factors to improve computational efficiency and accuracy, but how to reasonably optimize the mesh, especially for earth-rock dams on rock foundations, is a technical challenge that needs to be solved urgently. Summary of the invention

[0006] In view of the technical problems existing in the prior art, the present invention provides a two-dimensional grid generation method and system for finite element calculation of earth-rock dams aimed at optimizing the number of rock foundation grids. By constructing a five-node transition grid model that can be split into three isosceles right triangles and applying it to the entire rock foundation area, the transition from the dense grid of the dam body frame selection area with the largest cross-section of the earth-rock dam to the sparse grid deep in the rock foundation is achieved, thereby optimizing the number of rock foundation grids and effectively improving the accuracy and efficiency of two-dimensional finite element analysis calculations of earth-rock dams.

[0007] The two-dimensional grid generation method for finite element calculation of earth-rock dam for optimizing the number of rock foundation grids provided in this application adopts the following technical solutions:

[0008] The two-dimensional mesh generation method for finite element calculation of earth-rock dam for optimizing the number of rock foundation meshes includes the following steps:

[0009] Set relevant parameters, set the dam body frame selection area based on the maximum cross section of the earth-rock dam, extend and select the rock foundation rectangular frame based on the dam body frame selection area, and set the area within the rock rectangular frame;

[0010] Each area within the rectangular frame of the rock foundation is divided into horizontal layers and vertical strips;

[0011] All block areas formed by horizontal stratification and vertical striping within the rectangular frame of the rock foundation are meshed and all five-node transition meshes are identified;

[0012] Process and split the five-node transition grid into a three-node grid;

[0013] Merge all the grids within the rectangular frame of the rock foundation to generate a two-dimensional grid for finite element calculation of earth-rock dam.

[0014] Furthermore, the step of setting relevant parameters includes:

[0015] The positive direction of the X axis is from the upstream to the downstream of the dam, and the positive direction of the Y axis is from the bottom of the dam to the top of the dam.

[0016] The distance from the crest to the bottom of an earth-rock dam is H, i.e. the dam height H;

[0017] The maximum cross section of the earth-rock dam is a collection of the outer contour information of the dam body, the material partition boundary information and the filling phase boundary information of all cross sections of the earth-rock dam;

[0018] The dimensions of the rock foundation rectangular frame are from the top to the dam top, from the dam bottom foundation vertically extending downward by a distance E, from the dam heel horizontally extending upstream by a distance E on the left, and from the dam site horizontally extending downstream by a distance E on the right.

[0019] Further,

[0020] Wherein, E is the distance that the rock foundation rectangular frame extends downward vertically, upstream horizontally, and downstream horizontally based on the dam body framed area, respectively; N is a natural number, indicating the number of horizontal lines divided downward based on the dam foundation horizontal line, the number of vertical lines divided upstream based on the dam heel vertical line, and the number of vertical lines divided downstream based on the dam site vertical line; n=0, 2, …N-1; D is the standard size of the two-dimensional finite element calculation grid to be initially divided.

[0021] Furthermore, the area setting step includes:

[0022] The rectangular range formed by the long side formed by the connection between the dam heel and the dam site and the width from the dam bottom to the dam top is defined as the dam body frame selection area;

[0023] The rectangular range formed by the upper left vertex of the rock foundation rectangular frame and the dam heel as diagonal lines and the rectangular range formed by the upper right vertex of the rock foundation rectangular frame and the dam site as diagonal lines are both defined as area A;

[0024] The rectangular range formed by the long side formed by the connection between the dam heel and the dam site and the lower boundary of the rectangular frame from the dam bottom to the rock foundation is defined as area B;

[0025] The rectangular range formed by the lower left vertex of the rock foundation rectangular frame and the dam heel as diagonal lines and the rectangular range formed by the lower right vertex of the rock foundation rectangular frame and the dam site as diagonal lines are both defined as area C;

[0026] The horizontal elevation of the foundation is Y0, and the X coordinate of the dam heel is X U , the X coordinate of the dam toe is X D The elevations of the upper and lower frames of the rock foundation rectangular frame are Y ∞ and Y -∞ The X coordinates of the left and right frames of the rock foundation rectangle are X EU and X ED .

[0027] Furthermore, the steps of horizontally dividing the B and C regions include:

[0028] The level of the foundation horizontal line is set to 0, the elevation is Y0, and the X coordinates of the starting point and the end point are X EU and X ED ;

[0029] The foundation level is divided into N horizontal lines downwards. The levels of the horizontal lines in areas B and C are C 下 =1,2,…,N;

[0030] The distance between the nth horizontal line and the n-1th horizontal line is Y n =2 n-1 ×D, the X coordinates of the starting points of each horizontal line are X EU , the X coordinates of the end points are all X ED .

[0031] Furthermore, the step of dividing the A area and the dam body framed area into horizontal layers includes:

[0032] Horizontal layering with equal distance D is carried out from the foundation level to the upper boundary of the rock foundation rectangular frame;

[0033] The levels of each horizontal line start from the foundation horizontal line, and the Nth line in the positive direction of the Y axis. The levels of each horizontal line in area A and the dam body frame selection area are

[0034] The X coordinates of the starting points of the horizontal lines in area A and the dam body frame selection area are extended upstream by a certain distance D based on the X coordinate of the dam heel. EC The X coordinate of the end point is extended downstream by the same distance D based on the X coordinate of the dam site. EC ;

[0035] If the current horizontal line level C 上 Divisible by 2 S , then the extension distance: S=1,2,…N,S takes the horizontal line level C 上 Divisible by 2 S The maximum number of

[0036] If the current horizontal line level C 上 Divide by 2 and the remainder is 1, then the extension distance is: D EC =0×D.

[0037] Furthermore, the step of vertically dividing the A and C areas of the largest section of the earth-rock dam after horizontal layering into strips comprises:

[0038] The bar level of the vertical line at the dam heel and dam site is set to 0, and the X coordinates are X U and X D , and the Y coordinates of the starting points of the two vertical lines are both Y -∞ , the Y coordinates of the end points are all Y ∞ ;

[0039] N vertical lines are drawn upstream from the dam heel and downstream from the dam site. The vertical lines in areas A and C are T 左右 =1,2,…,N;

[0040] The distance between the nth vertical line and the n-1th vertical line is X n =2 n-1 ×D, the Y coordinate of the starting point of the Nth vertical line is: The Y coordinates of the end points are all Y ∞ .

[0041] Furthermore, the steps of vertically dividing the B area of ​​the largest section of the earth-rock dam and the dam body frame selection area after the horizontal layering include:

[0042] From the vertical line at the dam heel to the vertical line at the dam site, vertical strips with equal distance D are divided;

[0043] The level of each vertical line starts from the vertical line at the dam heel, and the level of the vertical line of the Nth line in the positive direction of the X axis, the B area of ​​the largest section of the earth-rock dam and the dam body frame selection area is

[0044] The Y coordinates of the starting points of each vertical line in the B area of ​​the largest section of the earth-rock dam and the dam body frame selection area extend vertically downward by a certain distance D based on the Y coordinate of the foundation horizontal line. ET , the Y coordinate of the end point is Y ∞ ;

[0045] If the current vertical line level T 中 Divisible by 2 S , then the extension distance: S=1,2,…N,S takes the vertical line level T 中 Divisible by 2 S The maximum number of

[0046] If the current vertical line level T 中 Divide by 2 and the remainder is 1, then the extension distance is: D ET =0×D.

[0047] Furthermore, the steps of processing and dividing the five-node transition grid into a three-node grid include:

[0048] All five-node transition grids are traversed, and the middle nodes on the horizontal or vertical lines of three consecutive nodes in all five-node transition grids are connected with two consecutive nodes on the adjacent horizontal or vertical lines to be cut into three-node grids.

[0049] On the other hand, the present invention provides a two-dimensional grid generation system for finite element calculation of earth-rock dams for optimizing the number of rock foundation grids, comprising:

[0050] An area setting module is used to set a dam body frame selection area based on the maximum cross section of the earth-rock dam, extend and select a rock foundation rectangular frame based on the dam body frame selection area, and perform area setting on the area within the rock rectangular frame;

[0051] Horizontal stratification and vertical striping division modules, which are used to divide each area within the rock foundation rectangular frame into horizontal stratification and vertical striping respectively;

[0052] A five-node transitional mesh recognition module is used to perform mesh recognition on all block areas formed after horizontal stratification and vertical striping within the rock foundation rectangular frame, and to recognize all five-node transitional meshes;

[0053] A five-node transition grid processing module, which is used to process and split the five-node transition grid into a three-node grid;

[0054] The merging module is used to merge all the grids in the rock foundation rectangular frame to generate a two-dimensional grid for finite element calculation of earth-rock dam.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] 1. Improve calculation efficiency. Compared with the prior art, the present invention reduces unnecessary calculations in finite element calculations by optimizing the number of grids in the rock foundation, thereby significantly improving calculation efficiency. This method is particularly suitable for the analysis of large earth-rock dam structures, and can significantly shorten calculation time while maintaining calculation accuracy.

[0057] 2. Optimize resource allocation. The present invention achieves a more reasonable allocation of computing resources by optimizing the rock foundation grid. Using denser grids in key areas to capture details and using sparser grids in non-key areas can reduce the waste of computing resources without sacrificing computing accuracy.

[0058] 3. Reduce costs. The optimized mesh generation method reduces the time and hardware resources required for calculations, thereby reducing the costs associated with earth-rock dam design and analysis. This is especially important for projects with limited budgets because it allows for more accurate analysis without incurring additional costs.

[0059] 4. Easy to integrate and expand. The method of the present invention can be easily integrated into the existing earth-rock dam design and analysis process, and can be expanded and optimized according to future technological developments to adapt to more complex engineering challenges. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The coordinate axes of all the drawings are in the same direction: the positive direction of the X axis is from the upstream to the downstream of the dam, and the positive direction of the Y axis is from the bottom of the dam to the top of the dam;

[0061] Figure 1 This is a flow chart of a two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of rock foundation grids in an embodiment of the present application;

[0062] Figure 2 This is the maximum cross-sectional view of the earth-rock dam in the embodiment of this application;

[0063] Figure 3 The dam body of the earth-rock dam with the largest cross section in the embodiment of the present application is selected by the frame;

[0064] Figure 4 The A, B and C areas are the largest sections of the earth-rock dam in the embodiment of the present application;

[0065] Figure 5 Related parameters defined for the maximum cross section of the earth-rock dam in the embodiment of this application;

[0066] Figure 6 This is a rendering of the maximum cross-section of the earth-rock dam after horizontal layering in the embodiment of the present application;

[0067] Figure 7 The maximum cross section of the earth-rock dam in the embodiment of this application is Figure 6 The effect diagram after the foundation is divided into vertical strips;

[0068] Figure 8 This is a rendering of the mesh of the dam body frame selection area of ​​the largest section of the earth-rock dam in the embodiment of the present application being optimized to be composed only of triangular meshes and quadrilateral meshes;

[0069] Fig. 9 A five-node transition grid formed by the interlayer between the 0th level line and the 1st level line in the embodiment of the present application;

[0070] Fig.10 A diagram showing the relationship between the five-node transition grid size and the sandwich horizontal line level in the embodiment of the present application;

[0071] Fig.11 A process diagram of splitting a five-node transition grid into three isosceles right triangles in an embodiment of the present application;

[0072] Fig.12 It is a two-dimensional finite element calculation grid diagram of the maximum cross-section of the earth-rock dam after merging the A, B, C areas and the dam body framed area in the embodiment of the present application;

[0073] Fig.13 This is a rendering of the rock foundation grid between the 0th level line and the 4th level line shown in the B area as an example in the embodiment of the present application, which realizes the transition from a dense grid to a sparse grid to optimize the number of rock foundation grids;

[0074] Fig.14 This is an effect diagram of all rock foundation grids shown in area B as an example after expanding one horizontal line in the embodiment of the present application, transitioning from dense grids to sparse grids to optimize the number of rock foundation grids. DETAILED DESCRIPTION

[0075] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0076] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described here can be implemented in an order other than that illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products or devices. The naming or numbering of steps in this application does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The process steps that have been named or numbered can change the execution order according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved. The division of units in this application is a logical division. There may be other division methods in actual application. For example, multiple units may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection between each other shown or discussed may be through some interfaces, and the indirect coupling or communication connection between units may be electrical or other similar forms, which are not limited in this application. Moreover, the units or sub-units described as separate components may or may not be physically separated, may or may not be physical units, or may be distributed in multiple circuit units, and some or all of the units may be selected according to actual needs to achieve the purpose of the present application.

[0077] Example 1

[0078] The following is combined with Figure 1-14 This application is described in further detail.

[0079] The present application embodiment discloses a two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of rock foundation grids. Figure 1 , the two-dimensional mesh generation method for finite element calculation of earth-rock dam for optimizing the number of rock foundation meshes includes the following steps:

[0080] S100: Figure 2 The maximum cross section of the earth-rock dam shown in the figure is used to define the region, and the Figure 3 The dam body framed area and Figure 4 The A, B, and C areas are shown in the figure, and the coordinate parameters of the four endpoints of the dam heel, dam site, foundation elevation, and rock foundation rectangular frame are set, as shown in Figure 5 As shown;

[0081] The positive direction of the X axis is from the upstream to the downstream of the dam, and the positive direction of the Y axis is from the bottom of the dam to the top of the dam.

[0082] The distance from the crest to the bottom of an earth-rock dam is H, i.e. the dam height H;

[0083] The maximum cross section of the earth-rock dam is a collection of the dam body contour information, material partition boundary information, and filling phase boundary information of all cross sections of the earth-rock dam.

[0084] The size of the rock foundation rectangular frame is from the top to the dam top, from the dam bottom foundation vertically extending downward by a distance E, from the dam heel horizontally extending upstream by a distance E on the left, and from the dam site horizontally extending downstream by a distance E on the right. In this embodiment, E=15D.

[0085] The region setting steps include:

[0086] The rectangular range formed by the long side formed by the connection between the dam heel and the dam site and the width from the dam bottom to the dam top is defined as the dam body frame selection area;

[0087] The rectangular range formed by the upper left vertex of the rock foundation rectangular frame and the dam heel as diagonal lines and the rectangular range formed by the upper right vertex of the rock foundation rectangular frame and the dam site as diagonal lines are both defined as area A;

[0088] The rectangular range formed by the long side formed by the connection between the dam heel and the dam site and the lower boundary of the rectangular frame from the dam bottom to the rock foundation is defined as area B;

[0089] The rectangular range formed by the lower left vertex of the rock foundation rectangular frame and the dam heel as diagonal lines and the rectangular range formed by the lower right vertex of the rock foundation rectangular frame and the dam site as diagonal lines are both defined as area C;

[0090] The horizontal elevation of the foundation is Y0, and the X coordinate of the dam heel is X U , the X coordinate of the dam toe is X D The elevations of the upper and lower frames of the rock foundation rectangular frame are Y ∞ and Y -∞ The X coordinates of the left and right frames of the rock foundation rectangle are X EU and X ED .

[0091] S200: Yes Figure 2 The area below the foundation level of the largest section of the earth-rock dam shown in the figure, namely, the B and C areas, are divided into horizontal layers, as shown in Figure 6 As shown in the lower part, the elevation of each horizontal layer line depends on the level of the horizontal line, but the X coordinates of the starting point and the end point are the same;

[0092] In this embodiment, the level of the foundation horizontal line is set to 0, the elevation is Y0, and the X coordinates of the starting point and the end point are X EU and XED ;

[0093] The foundation level is divided into 4 horizontal lines downwards. The levels of the horizontal lines in areas B and C are C 下 =1,2,…,4;

[0094] The elevations of the horizontal lines are Y0-D, Y0-3D, Y0-7D and Y0-15D respectively, and the X coordinates of the starting points are all X EU , the X coordinates of the end points are all X ED , so far the interlayer intervals formed between adjacent horizontal lines are D, 2D, 4D and 8D respectively;

[0095] right Figure 2 The area above the foundation horizontal line of the largest section of the earth-rock dam shown in the figure, namely area A and the dam body frame area, are divided into horizontal layers, as shown in Figure 6 As shown in the upper part, the elevations of the horizontal stratification lines are equidistant, but the X coordinates of the start and end points are determined according to the level of the horizontal line;

[0096] Horizontal layering with equal distance D is carried out from the foundation level to the upper boundary of the rock foundation rectangular frame;

[0097] The levels of each horizontal line start from the foundation horizontal line, and the Nth line in the positive direction of the Y axis. The levels of each horizontal line in area A and the dam body frame selection area are

[0098] The X coordinates of the starting points of each horizontal line extend upstream by a certain distance D based on the X coordinates of the dam heel. EC The X coordinate of the end point is extended downstream by the same distance D based on the X coordinate of the dam site. EC , so the X coordinate of the starting point of each horizontal line is X U -D EC , the X coordinate of the end point is X D +D EC , where the extension distance of each horizontal line is D EC It is calculated as follows:

[0099] If the current horizontal line level C 上 Divisible by 2 S , then the extension distance: S=1,2,…N,S takes the horizontal line level C 上 Divisible by 2 S The maximum number of

[0100] If the current horizontal line level C 上 Divide by 2 and the remainder is 1, then the extension distance is: D EC =0×D;

[0101] In this embodiment, N is 4 at most, that is, 4 horizontal lines are divided downward based on the horizontal line of the dam foundation, 4 vertical lines are divided upstream based on the vertical line of the dam heel, and 4 vertical lines are divided downstream based on the vertical line of the dam site. The maximum value of S can be 4. In this embodiment, the extension distance D of each horizontal line is calculated with 4 as the upper limit. EC :

[0102] If the current horizontal line level C 上 Divisible by 16, the extension distance is D EC =15×D;

[0103] If the current horizontal line level C 上 Divisible by 8, the extension distance is D EC =7×D;

[0104] If the current horizontal line level C 上 Divisible by 4, the extension distance is D EC =3×D;

[0105] If the current horizontal line level C 上 Divide by 2, then the extension distance is D EC =1×D;

[0106] If the current horizontal line level C 上 Divide by 2 and the remainder is 1, then the extension distance is D EC =0×D;

[0107] right Figure 6 The maximum cross-section of the earth-rock dam is shown in the figure. The dam heel is divided vertically into the upstream area and the downstream area below the dam site, namely, the A and C areas, as shown in the figure. Figure 7 As shown in the left and right parts, the X coordinates of each vertical line and the Y coordinates of the starting point are determined according to the vertical line level, but the Y coordinates of the end points are the same;

[0108] The step of vertically dividing the A and C areas of the largest section of the earth-rock dam after horizontal layering into strips comprises:

[0109] The bar level of the vertical line at the dam heel and dam site is set to 0, and the X coordinates are X U and X D , and the Y coordinates of the starting points of the two vertical lines are both Y -∞ , the Y coordinates of the end points are all Y ∞ ;

[0110] N vertical lines are drawn upstream from the dam heel and downstream from the dam site. The vertical lines in areas A and C are T 左右 =1,2,…,4;

[0111] In the A and C areas upstream of the dam heel, the X coordinates of the vertical lines arranged in order from the dam heel to the upstream are XU -D, X U -3D, X U -7D and X U -15D, the Y coordinates of the starting points are Y0-D, Y0-3D, Y0-7D and Y0-15D respectively, and the Y coordinates of the end points are all Y ∞ , so far the intervals between adjacent vertical lines are D, 2D, 4D and 8D respectively;

[0112] In the A and C areas downstream of the dam site, the X coordinates of the vertical lines arranged in order from the dam site to the downstream are X U +D, X U +3D, X U +7D and X U +15D, the Y coordinates of the starting points are Y0-D, Y0-3D, Y0-7D and Y0-15D respectively, and the Y coordinates of the end points are all Y ∞ , so far the intervals between adjacent vertical lines are D, 2D, 4D and 8D respectively;

[0113] right Figure 6 The area between the heel of the largest cross-section of the earth-rock dam and the dam site, that is, area B and the dam body frame area, are divided vertically into strips, as shown in Figure 7 As shown in the middle part, the X coordinates of the vertical lines are equally spaced, and the Y coordinates of the starting points are determined according to the vertical line level, but the Y coordinates of the end points are the same;

[0114] The steps of vertically dividing the B area of ​​the largest section of the earth-rock dam and the dam body frame selection area after horizontal layering include:

[0115] From the vertical line at the dam heel to the vertical line at the dam site, vertical strips with equal distance D are divided;

[0116] The level of each vertical line starts from the vertical line at the dam heel, and the level of the vertical line of the Nth line in the positive direction of the X axis, the B area of ​​the largest section of the earth-rock dam and the dam body frame selection area is

[0117] The Y coordinates of the starting points of each vertical line in the B area of ​​the largest section of the earth-rock dam and the dam body frame selection area extend vertically downward by a certain distance D based on the Y coordinate of the foundation horizontal line. ET , the Y coordinate of the end point is Y ∞ , where the extension distance of each vertical line is D ET It is calculated as follows:

[0118] If the current vertical line level T 中 Divisible by 2 S , then the extension distance: S=1,2,…N,S takes the vertical line level T 中 Divisible by 2S The maximum number of

[0119] If the current vertical line level T 中 Divide by 2 and the remainder is 1, then the extension distance is: D ET =0×D;

[0120] In this embodiment, N is 4 at most, that is, 4 horizontal lines are divided downward based on the horizontal line of the dam foundation, 4 vertical lines are divided upstream based on the vertical line of the dam heel, and 4 vertical lines are divided downstream based on the vertical line of the dam site. The maximum value of S can be 4. In this embodiment, the extension distance D of each vertical line is calculated with 4 as the upper limit. ET :

[0121] If the current vertical line level T 中 Divisible by 16, the extension distance is D ET =15×D;

[0122] If the current vertical line level T 中 Divisible by 8, the extension distance is D ET =7×D;

[0123] If the current vertical line level T 中 Divisible by 4, the extension distance is D ET =3×D;

[0124] If the current vertical line level T 中 Divide by 2, then the extension distance is D ET =1×D;

[0125] If the current vertical line level T 中 Divide by 2 and the remainder is 1, then the extension distance is D ET =0×D.

[0126] S300: Perform grid recognition on all block areas formed by horizontal stratification and vertical striping within the rectangular frame of the rock foundation, and recognize all five-node transition grids;

[0127] right Figure 7 Grid recognition is performed for all block areas. Each grid is an independent unit and does not contain any nodes. All five-node transition grids are identified.

[0128] right Figure 7 The mesh of the dam body is optimized by selecting the area of ​​the dam body, and a two-dimensional finite element calculation mesh consisting of only triangular meshes and quadrilateral meshes that can be recognized by the Solid185 unit in ANSYS is obtained. The optimization effect is as follows Figure 8 shown.

[0129] S400: The five-node grid transition grid is available in areas A, B, and C. Take area B as an example. Fig. 9As shown in the figure, the three adjacent continuous nodes of the 0th horizontal line and the two adjacent continuous nodes of the 1st horizontal line form a five-node transition grid, where the second node of the 0th horizontal line is a flat angle node, and the aspect ratio of the entire five-node transition grid is 2:1. The size of the five-node transition grid formed by the sandwich of the Nth horizontal line and the N+1th horizontal line is as follows: Fig.10 As shown, the process of splitting it into three isosceles right triangles is as follows Fig.11 As shown;

[0130] The three isosceles right triangles include:

[0131] The three nodes of the first isosceles right triangle are composed of the first node, the second node of the Nth horizontal line and the first node of the N+1th horizontal line;

[0132] The three nodes of the second isosceles right triangle are composed of the second node of the Nth horizontal line, the first node and the second node of the N+1th horizontal line;

[0133] The three nodes of the third isosceles right triangle are composed of the second node, the third node of the Nth horizontal line and the second node of the N+1th horizontal line.

[0134] S500: Merge all the grids in the A, B, C areas and the dam body frame area to obtain the following Fig.12 The two-dimensional finite element calculation grid of the largest section of the earth-rock dam shown in the figure. The optimization process of the number of grids in the entire rock foundation is to transition from the D-size dense grid at the boundary of the dam body frame selection area to the 8D-size sparse grid at the boundary of the rock foundation rectangular frame. Taking area B as an example, the grid transition effect and related dimensions from the 0th horizontal line to the 4th horizontal line are as follows: Fig.13 As shown, the entire B area is expanded by one more horizontal line. The grid transition effect and related dimensions are as follows Fig.14 shown.

[0135] Example 2

[0136] This embodiment provides a two-dimensional grid generation system for finite element calculation of earth-rock dams for optimizing the number of grids in rock foundations, including:

[0137] An area setting module is used to set a dam body frame selection area based on the maximum cross section of the earth-rock dam, extend and select a rock foundation rectangular frame based on the dam body frame selection area, and perform area setting on the area within the rock rectangular frame;

[0138] Horizontal stratification and vertical striping division modules, which are used to divide each area within the rock foundation rectangular frame into horizontal stratification and vertical striping respectively;

[0139] A five-node transitional mesh recognition module is used to perform mesh recognition on all block areas formed after horizontal stratification and vertical striping within the rectangular frame of the rock foundation, and to recognize all five-node transitional meshes;

[0140] A five-node transition grid processing module, which is used to process and split the five-node transition grid into a three-node grid;

[0141] The merging module is used to merge all the grids in the rock foundation rectangular frame to generate a two-dimensional grid for finite element calculation of earth-rock dam.

[0142] The above is only a preferred 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 conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

[0143] It should be understood that parts not elaborated in detail in this specification belong to the prior art.

[0144] It should be understood that the above description of the preferred embodiment is relatively detailed and cannot be regarded as limiting the scope of patent protection of the present invention. Under the enlightenment of the present invention, ordinary technicians in this field can also make substitutions or modifications without departing from the scope of protection of the claims of the present invention, which all fall within the scope of protection of the present invention. The scope of protection requested for the present invention shall be based on the attached claims.

Claims

1. A two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of grids in rock foundations, characterized by: The following steps are involved: Set relevant parameters, set the dam body frame selection area based on the maximum cross section of the earth-rock dam, extend and select the rock foundation rectangular frame based on the dam body frame selection area, and set the area within the rock rectangular frame; Each area within the rectangular frame of the rock foundation is divided into horizontal layers and vertical strips; All block areas formed by horizontal stratification and vertical striping within the rectangular frame of the rock foundation are meshed and all five-node transition meshes are identified; Process and split the five-node transition grid into a three-node grid; Merge all the grids within the rectangular frame of the rock foundation to generate a two-dimensional grid for finite element calculation of earth-rock dam.

2. The two-dimensional grid generation method for finite element calculation of earth-rock dam for optimizing the number of grids in rock foundation according to claim 1 is characterized by: The step of setting relevant parameters comprises: The positive direction of the X axis is from the upstream to the downstream of the dam, and the positive direction of the Y axis is from the bottom of the dam to the top of the dam. The distance from the crest to the bottom of an earth-rock dam is H, i.e. the dam height H; The maximum cross section of the earth-rock dam is a collection of the outer contour information of the dam body, the material partition boundary information and the filling phase boundary information of all cross sections of the earth-rock dam; The dimensions of the rock foundation rectangular frame are from the top to the dam top, from the dam bottom foundation vertically extending downward by a distance E, from the dam heel horizontally extending upstream by a distance E on the left, and from the dam site horizontally extending downstream by a distance E on the right.

3. The two-dimensional grid generation method for finite element calculation of earth-rock dam for optimizing the number of grids in rock foundation according to claim 2 is characterized by: Wherein, E is the distance that the rock foundation rectangular frame extends downward vertically, upstream horizontally, and downstream horizontally based on the dam body framed area, respectively; N is a natural number, indicating the number of horizontal lines divided downward based on the dam foundation horizontal line, the number of vertical lines divided upstream based on the dam heel vertical line, and the number of vertical lines divided downstream based on the dam site vertical line; n=0, 2, …N-1; D is the standard size of the two-dimensional finite element calculation grid to be initially divided.

4. The two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of grids for rock foundations according to claim 3 is characterized by: The area setting step comprises: The rectangular range formed by the long side formed by the connection between the dam heel and the dam site and the width from the dam bottom to the dam top is defined as the dam body frame selection area; The rectangular range formed by the upper left vertex of the rock foundation rectangular frame and the dam heel as diagonal lines and the rectangular range formed by the upper right vertex of the rock foundation rectangular frame and the dam site as diagonal lines are both defined as area A; The rectangular range formed by the long side formed by the connection between the dam heel and the dam site and the lower boundary of the rectangular frame from the dam bottom to the rock foundation is defined as area B; The rectangular range formed by the lower left vertex of the rock foundation rectangular frame and the dam heel as diagonal lines and the rectangular range formed by the lower right vertex of the rock foundation rectangular frame and the dam site as diagonal lines are both defined as area C; The horizontal elevation of the foundation is Y0, and the X coordinate of the dam heel is X U , the X coordinate of the dam toe is X D The elevations of the upper and lower frames of the rock foundation rectangular frame are Y ∞ and Y -∞ The X coordinates of the left and right frames of the rock foundation rectangle are X EU and X ED .

5. The two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of grids for rock foundations according to claim 4 is characterized by: The steps for horizontally dividing areas B and C include: The level of the foundation horizontal line is set to 0, the elevation is Y0, and the X coordinates of the starting point and the end point are X EU and X ED ; The foundation level is divided into N horizontal lines downwards. The levels of the horizontal lines in areas B and C are C 下 =1,2,…,N; The distance between the nth horizontal line and the n-1th horizontal line is Y n =2 n-1 ×D, the X coordinates of the starting points of each horizontal line are X EU , the X coordinates of the end points are all X ED .

6. The two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of grids in rock foundations according to claim 4 is characterized by: The step of horizontally dividing the A area and the dam body frame selection area into layers comprises: Horizontal layering with equal distance D is carried out from the foundation level to the upper boundary of the rock foundation rectangular frame; The levels of each horizontal line start from the foundation horizontal line. The levels of each horizontal line in area A and the dam body frame selection area are The X coordinates of the starting points of the horizontal lines in area A and the dam body frame selection area are extended upstream by a certain distance D based on the X coordinate of the dam heel. EC The X coordinate of the end point is extended downstream by the same distance D based on the X coordinate of the dam site. EC ; If the current horizontal line level C 上 Divisible by 2 S , then the extension distance: S takes the horizontal level C 上 Divisible by 2 S The maximum number of If the current horizontal line level C 上 Divide by 2 and the remainder is 1, then the extension distance is: D EC =0×D.

7. The two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of grids in rock foundations according to claim 4 is characterized by: The step of vertically dividing the A and C areas of the largest section of the earth-rock dam after horizontal layering into strips comprises: The bar level of the vertical line at the dam heel and dam site is set to 0, and the X coordinates are X U and X D , and the Y coordinates of the starting points of the two vertical lines are both Y -∞ , the Y coordinates of the end points are all Y ∞ ; N vertical lines are drawn upstream from the dam heel and downstream from the dam site. The vertical lines in areas A and C are T 左右 =1,2,…,N; The distance between the nth vertical line and the n-1th vertical line is X n =2 n-1 ×D, the Y coordinate of the starting point of the Nth vertical line is: The Y coordinates of the end points are all Y ∞ .

8. The two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of grids for rock foundations according to claim 4 is characterized by: The steps of vertically dividing the B area of ​​the largest section of the earth-rock dam and the dam body frame selection area after horizontal layer division include: From the vertical line at the dam heel to the vertical line at the dam site, vertical strips with equal distance D are divided; The level of each vertical line starts from the vertical line at the dam heel, and the level of the vertical line of the Nth line in the positive direction of the X axis, the B area of ​​the largest section of the earth-rock dam and the dam body frame selection area is The Y coordinates of the starting points of each vertical line in the B area of ​​the largest section of the earth-rock dam and the dam body frame selection area extend vertically downward by a certain distance D based on the Y coordinate of the foundation horizontal line. ET , the Y coordinate of the end point is Y ∞ ; If the current vertical line level T 中 Divisible by 2 S , then the extension distance: S takes vertical line level T 中 Divisible by 2 S The maximum number of; If the current vertical line level T 中 Divide by 2 and the remainder is 1, then the extension distance is: D ET =0×D.

9. The two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of grids in rock foundations according to claim 1 is characterized by: The steps of processing and dividing the five-node transition grid into a three-node grid include: All five-node transition grids are traversed, and the middle nodes on the horizontal or vertical lines of three consecutive nodes in all five-node transition grids are connected with two consecutive nodes on the adjacent horizontal or vertical lines to be cut into three-node grids.

10. A two-dimensional grid generation system for finite element calculation of earth-rock dams for optimizing the number of grids in rock foundations, characterized by: include: An area setting module is used to set a dam body frame selection area based on the maximum cross section of the earth-rock dam, extend and select a rock foundation rectangular frame based on the dam body frame selection area, and perform area setting on the area within the rock rectangular frame; Horizontal stratification and vertical striping division modules, which are used to divide each area within the rock foundation rectangular frame into horizontal stratification and vertical striping respectively; A five-node transitional mesh recognition module is used to perform mesh recognition on all block areas formed after horizontal stratification and vertical striping within the rectangular frame of the rock foundation, and to recognize all five-node transitional meshes; A five-node transition grid processing module, which is used to process and split the five-node transition grid into a three-node grid; A merging module, which is used to merge all the grids in the rectangular frame of the rock foundation to generate a two-dimensional grid for finite element calculation of earth-rock dam; The two-dimensional grid generation system for finite element calculation of earth-rock dams for optimizing the number of rock foundation grids is used to execute the steps in the two-dimensional grid generation method for finite element calculation of earth-rock dams for optimizing the number of rock foundation grids as described in any one of claims 1-9.

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