A refined batch processing method for directly facing cross - plate grids in fatigue hot spot areas

Abstract

A refined batch processing method for the grid of the straight-face intersection plate in the fatigue hot spot area of the present invention includes the following steps: Based on the three-dimensional template of the straight-face intersection plate, obtain the geometric dimension parameters of the straight-face intersection plate; Based on the obtained geometric dimension parameters of the straight-face intersection plate, identify the type of the hot spot area structure of the straight-face intersection plate; For the identified hot spot area of the type, perform batch grid refinement processing. The present invention can be very conveniently applied to any straight-panel structure regarding fatigue hot spot analysis. Only need to specify the location of the hot spot, establish a local coordinate system at this hot spot, and then obtain the geometric dimension parameters, identify the type of the hot spot area structure, and refine the grid. The greatest advantage of this method is that it can ignore any other situations and can run as long as the structure type conforms. Therefore, it can batch process hundreds or thousands of similar fatigue hot spot grid situations, saving a large amount of time and improving production efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of ship engineering and relates to a method for refined batch processing of the grid of directly facing cross plates in fatigue hot spots areas. Background Art

[0002] Currently, the hot spot stress method is mainly adopted for fatigue problems. It mainly involves simulating finite element modeling of areas prone to fatigue, then performing refined processing of t×t grids on hot spot areas according to the requirements of DNV specifications and CCS specifications, while meeting the requirements of transition grids, and then extracting the hot spot stress at the hot spots. However, this method requires manual operation, which is very cumbersome and complex. If there are a large number of hot spots, it is an extremely difficult task. Summary of the Invention

[0003] To solve the above problems, the technical solution adopted by the present invention is: a method for refined batch processing of the grid of directly facing cross plates in fatigue hot spots areas, including the following steps:

[0004] Based on the three-dimensional template of the directly facing cross plate, obtain the geometric dimension parameters of the directly facing cross plate;

[0005] Based on the obtained geometric dimension parameters of the directly facing cross plate, identify the type of the hot spot area structure of the directly facing cross plate;

[0006] Perform batch grid refinement processing on the identified hot spot areas.

[0007] Further, the types of the hot spot area structures of the directly facing cross plate include: non-through cross surface, non-through T-shaped surface, through eleven-shaped surface, and through double-ten-shaped surface.

[0008] Further, the process of obtaining the geometric dimension parameters of the directly facing cross plate based on the three-dimensional template of the directly facing cross plate is as follows:

[0009] Taking the hot spot as the reference, obtain the distance length from the end point on the edge line segment of the geometric surface falling on the coordinate axis to the hot spot.

[0010] The method for obtaining the distance length from the end point of the edge line segment to the hot spot is as follows:

[0011] Determine the two direction positions in the radial direction of the line segment, and then increase the distance little by little in the axial direction of the line segment until the geometric midpoint of this line is selected, that is, this line segment is selected;

[0012] Then select the straight line where the line segment is located,

[0013] After selecting this straight line, the distance from the end point of this line segment to the coordinate origin can be obtained,

[0014] The method for obtaining the dimensions of the Y-axis and Z-axis of the first layer is the same as the method for obtaining the dimension of the X-axis of one face of the first layer;

[0015] As needed, not only can the distance from the outer endpoint on the first layer to the hot spot be obtained, but also the distance from the outer endpoint of the line segment on the second or third layer to the hot spot can be directly obtained by skipping the first layer.

[0016] Furthermore, the functions and formulas for obtaining the geometric dimension parameters of the straight-face cross plate are as follows:

[0017] *use,select_layer.mac,1,'x','+',0.1(1)

[0018]

[0019]

[0020] Where: The length should depend on the actual line segment length;

[0021] Formula (1) is the usage method of the geometric dimension parameter acquisition function. In the formula, the fourth parameters a, b, c, and d, where a represents the layer number, which is an Arabic numeral; parameter b represents the axis name, and the three characters x, y, and z can be selected; parameter c represents the axis direction, and the two characters - and + can be selected; parameter d represents the inverted triangle in formula 4, which is the length increment and is a number;

[0022] *use,select_layer.mac,2,'x','+',0.1 means that on the positive x-axis, the length of the distance from the outer endpoint of the upper line segment on the second layer to the hot spot is obtained, and it increases with an increment of 0.1.

[0023] Formula (2) is the command stream for selecting the line segment in the ANSYS software;

[0024] Formula (3) is the explanation of the fifth and sixth parameters x1 and x2 in the first function of formula (2), where the inverted triangle is a number, named the length increment, which is approximately one-tenth of the length of the selected line segment.

[0025] Furthermore, the process of identifying the type of the hot spot area structure of the straight-face cross plate based on the obtained geometric dimension parameters of the straight-face cross plate includes two aspects: identifying whether the hot spot area structure contains an inclined plane and identifying the type of the hot spot area structure;

[0026] The method used to identify the type of the hot spot area structure is to select a position in the space coordinate system, then determine the existence of a geometric plane in the space, and judge the type of the hot spot area structure based on the number of geometric planes;

[0027] To determine whether the identified hot spot area structure contains an inclined plane, each octant is selected in turn through the command of selecting a plane in space, and it is checked whether there is a plane in each octant. If there is, it proves the existence of an inclined plane in the structure.

[0028] Further, the batch grid refinement process for the identified type of hot spot area includes the following steps:

[0029] Surface cutting: After selecting the interface, a refined grid area with a thickness 10 times that of the surface needs to be cut out according to the requirement of t×t, and then a transition grid area with a specific shape is cut out;

[0030] Obtaining material properties and reassigning material properties: The spatial geometric surface is selected through a function, and then the material properties of each spatial surface are obtained through a function and stored in the surface property storage array. Based on the information obtained from the surface property storage array, the surface is reassigned properties.

[0031] Further, the surface cutting: The process of cutting out a refined grid area with a thickness 10 times that of the surface and then a transition grid area with a specific shape after selecting the interface includes the following steps:

[0032] Grid area division: First, the side length cut1 of the refined area is determined according to the plate thickness and specifications, and the refined area rectangle is divided;

[0033] Then, according to the principle of smooth transition, four layers of transition grid areas are divided, with side lengths cut2, cut3, cut6, and cut4 in sequence, where the side length of the outermost area is set as cut4;

[0034] Finally, the connection relationship between the transition area grid and the first-layer geometric surface is processed;

[0035] Adjust the transition grid area.

[0036] A method for batch refinement of the grid of the straight-plane intersection plate in the fatigue hot spot area provided by the present invention can be very conveniently applied to any straight-panel structure regarding fatigue hot spot analysis. Only the location of the hot spot needs to be specified, a local coordinate system is established at this hot spot, and then the geometric dimension parameters are obtained, the type of the hot spot area structure is identified, and the grid is refined. It is very convenient to divide a refined grid and a matching transition grid near the hot spot. The greatest advantage of this method is that it can ignore any other situations and can run as long as the structure type meets the requirements. Therefore, it can batch process hundreds or thousands of similar fatigue hot spot grid situations, saving a large amount of time and improving production efficiency. Brief Description of the Drawings

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 It is a non-through cross-sectional structure diagram;

[0039] Figure 2 It is a non-through T-shaped cross-sectional structure diagram;

[0040] Figure 3 It is a through eleven-shaped cross-sectional structure diagram;

[0041] Figure 4 It is a through double-ten-shaped cross-sectional structure diagram;

[0042] Figure 5 It is a geometric surface distribution diagram near the hot spot;

[0043] Figure 6 It is a line segment distribution diagram near the hot spot;

[0044] Figure 7 It is a spatial coordinate system diagram;

[0045] Figure 8 It is a schematic diagram of the XOY coordinate plane segmentation;

[0046] Figure 9 It is a grid display diagram of the refined area and the transition area of the XOY coordinate plane;

[0047] Figure 10 It is a Hi<cut4 cutting display diagram;

[0048] Figure 11 It is a Hi>>cut4 cutting display diagram;

[0049] Figure 12 It is a Hi>cut4 and cut4 is closer to the Hi cutting display diagram;

[0050] Figure 13 It is an oblique cutting diagram;

[0051] Figure 14 It is a straight cutting diagram;

[0052] Figure 15 It is the first type of cutting - oblique cutting;

[0053] Figure 16 It is the second type of cutting - edge cutting;

[0054] Figure 17is the third type of cutting - linear cutting;

[0055] Figure 18 is the refined diagram of the through - double - ten - shaped surface grid;

[0056] Figure 19 is the refined diagram of the through - eleven - shaped surface grid;

[0057] Figure 20 In (a) is the front view of the refined non - through cross - shaped surface grid, and (b) is the bottom view of the refined non - through cross - shaped surface grid;

[0058] Figure 21 In (a) is the front view of the refined non - through T - shaped surface grid, and (b) is the bottom view of the refined non - through T - shaped surface grid;

[0059] Figure 22 is the fine - grid model and partial enlarged model diagram of the connection between the bottom plate of the B - type cabin and the bottom support;

[0060] Figure 23 In (a) is the front view of the refined model of the outer wall surface of the LNG B - type cabin, and (b) is the side view of the refined model of the outer wall surface of the LNG B - type cabin. Specific embodiments

[0061] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0063] It should be noted that the terms used here are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used here, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or their combinations.

[0064] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed here, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, further discussion thereof is not required in subsequent drawings.

[0065] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc. are generally based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description. Without contrary statements, these orientation terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of the present invention: the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0066] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "above-mentioned", etc. may be used here to describe the spatial positional relationships of one device or feature to other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation described in the drawings for the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned "below other devices or structures" or "beneath other devices or structures". Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0067] In addition, it should be noted that the use of words such as "first", "second", etc. to limit components is only for the convenience of differentiating the corresponding components. Without otherwise stating, the above words have no special meanings. Therefore, they should not be construed as limiting the scope of protection of the present invention.

[0068] A refined batch processing method for directly facing cross - plate grids in fatigue hot - spot areas, comprising the following steps:

[0069] S1: Based on the three - dimensional template of the directly facing cross - plate, obtain the geometric dimension parameters of the directly facing cross - plate;

[0070] S2: Based on the obtained geometric dimension parameters of the directly facing cross - plate, identify the types of the hot - spot area structures of the directly facing cross - plate;

[0071] S3: Perform batch - type grid refinement processing on the identified hot - spot areas.

[0072] Steps S1 / S2 / S3 are executed in sequence;

[0073] Furthermore, the types of the hot - spot area structures of the directly facing cross - plate include: non - through cross - surface, non - through T - shaped surface, through eleven - shaped surface, and through double - cross - shaped surface.

[0074] By querying and comparing the introductions related to fatigue assessment in DNV specifications and CCS specifications, six general fatigue hot - spot positions in the cabin are summarized as shown in Table 1 below.

[0075] Serial number Key parts for fatigue assessment 1 Bottom hopper knuckle connection 2 Connection at the root of the horizontal girder 3 Knuckle connection between the bottom stool and the inner bottom 4 Connection between the corrugated bulkhead and the bottom stool 5 Connection between the side frame bracket and the inclined plate of the bottom hopper 6 Tank corner and end bracket of the hatch coaming

[0076] After studying the above - mentioned structures, it can be found that these structures are not of arbitrary shapes but follow certain rules. By studying these rules, they can be well utilized, and thus the refined grids for batch processing can become more concise and fast. By observing that the structures in the cabin hot - spot areas are mostly cases of straight - plate intersections, they can be simplified into 4 structures,

[0077] Figure 1 is the structure diagram of the non - through cross - surface;

[0078] Figure 2 is the structure diagram of the non - through T - shaped surface;

[0079] Figure 3 is the structure diagram of the through eleven - shaped surface;

[0080] Figure 4 is the structure diagram of the through double - cross - shaped surface;

[0081] Furthermore, the process of obtaining the geometric dimension parameters of the directly facing cross - plate is as follows:

[0082] Locate the hot - spot point. A new local coordinate system can be manually established at the hot - spot by clicking with the mouse to facilitate subsequent operations.

[0083] Reason: Grid refinement requires corresponding Boolean operations on the geometric surfaces near the hot spots. Therefore, the prerequisite is to be able to select these geometric surfaces individually. After establishing the local coordinate system, the desired geometric lines and surfaces are mainly selected by means of spatial range selection. However, in various geometric models that require fatigue calculation, they are generally composed of rectangular geometric surfaces with different lengths and widths, and most of the hot spots are distributed at the intersections of these geometric surfaces. Since it is difficult to know the size of each surface, it is also difficult to select the desired geometric surface. Therefore, the size parameters of these surfaces are needed at this time.

[0084] The idea of obtaining the geometric size parameters of the straight cross plate is as follows: Since the surfaces at the hot spots are arranged in sequence, the first layer of surfaces at the hot spot is the innermost 4 surfaces, and the second layer is the outermost 12 surfaces. Figure 5 is the distribution diagram of geometric surfaces near the hot spot; To select the innermost 4 surfaces, it is not necessary to know the length and width of each of these 4 surfaces. Only 4 values on the positive and negative axes of the X and Y axes are required. Similarly, to select all the surfaces of the second layer and the first layer, only 4 values on the positive and negative axes of the X and Y axes of the second layer are needed. How to find the parameters of each layer of surfaces on the positive and negative axes of the X, Y, and Z axes is the next task.

[0085] In the ANSYS software, to select a line through the position coordinates, in fact, it is not necessary to directly write out the position range of this line in the coordinate system. Only the coordinates covering or including the geometric center point of the line need to be written. According to this principle,

[0086] Determine the two direction positions in the radial direction of the line segment;

[0087] Then increase the distance little by little in the axial direction of the line segment until the geometric midpoint of this line is selected, and then this line segment can be selected;

[0088] After selecting this line, the distance from the outer end point of this line to the origin of the coordinates can be obtained.

[0089] Figure 6 is the distribution diagram of line segments near the hot spot; There are four geometric surfaces distributed in the local coordinate system, and the intersecting edges of them are line segments 1, 2, 3, and 4 distributed on the coordinate axes respectively. The starting point coordinates of line segment 1 are (0, 0, 0), and the outer end point coordinate value is (4, 0, 0). Therefore, the length of this line segment is 4, and the midpoint coordinate value is (2, 0, 0).

[0090] Taking the example of obtaining the distance from the outer end point of line segment 1 to the origin to illustrate the realization of the function of the geometric size parameter acquisition function. First, it is necessary to select line segment 1. By using the command for spatial selection of lines in the APDL command stream, fix the Y and Z coordinates and increase the X coordinate by ▽ = 0.4 each time starting from x1 = 0 until xi When it increases to 2, this line segment can be selected, as shown in formula (2).

[0091] *use,select_layer.mac,1,'x','+',0.4(1)

[0092]

[0093]

[0094] Wherein: The length should depend on the actual length of the line segment, approximately about one-tenth of the line segment length.

[0095] Formula (1) is the usage method of the geometric dimension parameter acquisition function. There are 4 parameters a, b, c, and d in the formula. Among them, a represents the layer number, which is an Arabic numeral; parameter b represents the axis name, and the three characters x, y, and z can be selected; parameter c represents the axis direction, and the two characters - and + can be selected; parameter d represents the inverted triangle in formula 4, which is the length increment and is a number;

[0096] *use,select_layer.mac,1,'x','+',0.4 means to obtain the length from the outer end point of the upper line segment on the first layer to the hot spot in the positive x-axis direction, and increase it by an increment of 0.4.

[0097] Formula (2) is the command stream for selecting a line segment in ANSYS software. X1 is the starting coordinate of the x-axis, and X2 is the ending coordinate of the x-axis.

[0098] Formula (3) is the explanation of the fifth and sixth parameters x1 and x2 in the first function of formula (2). Among them, the inverted triangle is a number, named the length increment, approximately about one-tenth of the length of the selected line segment.

[0099] Furthermore, in order to ensure the healthy operation of the geometric dimension acquisition function, some corresponding additional functions need to be added to the function.

[0100] It can run in any one of the six directions of the coordinate axis and output the distance from the end point of the last line segment to the origin.

[0101] When there is no line segment in a certain direction of the coordinate axis, a command to continuously obtain the center point of the line segment will fall into an endless loop and cannot exit the program. Therefore, a specified number of loop steps need to be added to the command. When the command does not find a line segment within the specified number of steps, it can automatically exit the program, and the output distance should be 0.

[0102] When there are fewer layers of line segments to be searched in a certain direction of the coordinate axis, for example, when there is only one or two line segments in a certain direction, while three line segments are to be searched. It is required that the command can exit when the third line segment cannot be found, and output the distance from the end point of the second line segment to the origin.

[0103] Further, based on the obtained geometric dimension parameters of the direct-plane intersection board, the process of identifying the type of the hot spot area structure of the direct-plane intersection board is as follows:

[0104] According to the knowledge of the Cartesian space coordinate system: Any two coordinate axes determine a plane, and thus three mutually perpendicular planes can be determined, which are collectively called coordinate planes. Among them, the coordinate plane determined by the X-axis and the Y-axis is called the XOY plane. Similarly, there are the YOZ plane and the ZOX plane. And each coordinate plane is divided into four small coordinate planes by the coordinate axes. For example, the XOY plane can be divided into four small coordinate planes: (+X)O(+Y), (+X)O(-Y), (-X)O(+Y), and (-X)O(-Y). Similarly, the YOZ plane and the ZOX plane can also be divided into 4 small coordinate planes respectively. Figure 7 It is a spatial coordinate system diagram.

[0105] The three coordinate planes divide the space into eight parts, and each part is called a quadrant. As Figure 7 shown, the eight quadrants are represented by the letters Ⅰ, Ⅱ,..., Ⅷ respectively. Among them, the quadrant containing the positive semi-axes of the X-axis, Y-axis, and Z-axis is the first quadrant. The other three quadrants on the XOY plane are arranged in the counterclockwise direction, which are the second, third, and fourth quadrants in turn; the fifth quadrant adjacent to the first quadrant below the XOY plane, and then arranged in the counterclockwise direction in turn are the sixth, seventh, and eighth quadrants, as Figure 7 shown.

[0106] Identifying the hot spot area structure should include two parts: identifying whether the hot spot area structure contains an inclined plane; identifying the type of the hot spot area structure.

[0107] The method for identifying the type of the hot spot area structure described above includes the following steps:

[0108] Select a position in the spatial coordinate system;

[0109] Then check how many geometric planes exist in this space;

[0110] Judge the type of the hot spot area structure according to the number of planes.

[0111] By using the command of selecting planes in space, one dimension is fixed each time while the other two dimensions are changed. For example, on the YOZ plane, set X to 0. By changing the coordinates of Y and Z, the four small coordinate planes on the YOZ coordinate plane can be selected. For instance, to select the small coordinate plane (+Y)O(+Z), set the X value to 0; set the Y value to 0 and Y2, where Y2 is the length of the upper side of the first acquired layer in the positive X-axis direction; set the Z value to 0 and Z2, where Z2 is the length of the upper side of the first acquired layer in the positive Z-axis direction, as shown in Equation 4 below. The selection methods for the other three small coordinate planes are shown in Equations 5 to 7 below. Similarly, the small coordinate planes on the ZOX and XOY coordinate planes can also be selected by this kind of method. Then, determine whether there is a geometric plane on each small coordinate plane. If it exists, record it as 1; if not, record it as 0. By judging the number of 0s and 1s, determine the presence or absence of geometric planes on each small coordinate plane, and then the type of the hot spot region structure can be identified.

[0112] The command of selecting planes in space determines the type of the hot spot region structure as follows:

[0113]

[0114]

[0115]

[0116]

[0117] The method for judging whether the hot spot region structure contains an inclined plane is similar to identifying the type of the hot spot region structure. The steps of the method for judging whether the hot spot region structure contains an inclined plane are as follows:

[0118] Select each octant in turn by using the command of selecting planes in space;

[0119] Check whether there is a plane in each octant;

[0120] If it exists, it proves that the structure has an inclined plane.

[0121] For the identified type of hot spot region, the batch grid refinement process includes the following steps:

[0122] S31: Obtain material properties: Select the spatial geometric plane through a function, and then obtain the material properties of each spatial plane through a function, and store the material properties in the surface property storage array;

[0123] S32: Surface cutting: After selecting the interface, a refined grid region with a thickness 10 times that of the surface needs to be cut out according to the requirements, and then a transition grid region with a specific shape is cut out;

[0124] S33: Reassign material properties again: By obtaining the information in the surface property storage array and then reassigning properties to the surface.

[0125] Further, surface cutting: After selecting the interface, a refined grid area with a thickness 10 times that of the surface needs to be cut out according to the requirements, and then a transition grid area with a specific shape needs to be cut out, including the following steps:

[0126] After selecting the interface, a refined grid area with a thickness 10 times that of the surface needs to be cut out according to the requirement of t×t. Moreover, for the convenience of the transition grid, a transition grid area with a specific shape also needs to be cut out.

[0127] Further, the process of obtaining material properties is as follows:

[0128] When a surface is divided, all the information on the surface will be lost. Therefore, before cutting the surface, the properties originally assigned to the surface need to be obtained and placed in a specified array for subsequent operations. After cutting the surface, the original surface properties obtained also need to be reassigned to the new surfaces formed after cutting.

[0129] Obtain surface properties: First, select the spatial geometric surface through a function, and then obtain the material properties of each spatial surface through a function and store these material properties in the surface property storage array, as shown in Table 2.

[0130] Table 2 Surface property storage array

[0131]

[0132] 3.2.1 Mesh area division, and the mesh area division includes the following steps:

[0133] First, determine the side length cut1 of the refined area according to the plate thickness and specifications;

[0134] And divide the refined area rectangle, Figure 8 which is a schematic diagram of the division of the XOY coordinate plane;

[0135] Then, according to the principle of smooth transition, divide four layers of transition mesh areas, and their side lengths are cut2, cut3, cut6, and cut4 in sequence, where the side length of the outermost area is set as cut4, as shown in Equation 8 below;

[0136]

[0137] where: th is the thickness of the panel;

[0138] Finally, process the connection relationship between the transition area mesh and the first-layer geometric surface.

[0139] The specific method of the cutting plane is to save the coordinates of the points to be cut into a prepared array;

[0140] Then, according to the requirements, these points are established and connected to form lines, and these lines are used to cut the plane. In this way, the required refined mesh area and transition mesh area are obtained. Figure 9 It is a diagram showing the refined area and transition area of the XOY coordinate plane;

[0141] Furthermore, the adjustment process of the transition mesh area is as follows:

[0142] After drawing the transition area, it is necessary to connect the four corner points a, b, c, and d of the square transition area to the four corner points A, B, C, and D of the first-layer geometric surface in order to better obtain a transition mesh with better quality. Since the side length cut4 of the square transition mesh area is generally fixed, while the side length H of the first-layer geometric surface is random and arbitrary. Therefore, when connecting the corner points of the square transition area to the corner points of the first-layer geometric surface, the following situations may occur:

[0143] When Hi < cut4, the plane cannot be cut normally. Figure 10 It is a cutting diagram of Hi < cut4;

[0144] When Hi >> cut4, the plane can be cut normally. Figure 11 It is a cutting diagram of Hi >> cut4;

[0145] When Hi > cut4 and cut4 is relatively close to Hi, after connecting the corner points of the square transition area to the corner points of the first-layer geometric surface, the cut surface will obtain very sharp elements. Figure 12 It is a cutting diagram of Hi > cut4 and cut4 is relatively close to Hi; this needs to be avoided during mesh analysis;

[0146] Where: Hi is the minimum side length of any surface

[0147] cut4 is the outermost range of the plane cutting, approximately 40 times the plate thickness.

[0148] Therefore, in order to handle these situations, we need to judge the length and width dimensions of the plane, and select the cutting type by judging the rectangularity of the plane.

[0149] Types of cutting: One is oblique cutting, and the other is square cutting.

[0150] For oblique cutting, directly connect the corner point d of the square transition area to the corner point D of the geometric surface. Figure 13 It is a diagram of oblique line cutting;

[0151] Square cutting is to connect points d and d1, d and d2 respectively, making line segments dd1 and dd2 perpendicular to the sides of the geometric surface. Figure 14 It is a straight-line cutting diagram;

[0152] The length of the surface is L and the width is H. Let ratio = H / L, named as the length-width ratio; cut4 is the outermost range of the surface cutting, approximately 40 times the plate thickness; minl is the shortest side length among all surfaces. cut4 and minl are important factors affecting the grid transition. Therefore, to draw a qualified grid, the range of the length-width ratio needs to be considered and the sizes of cut4 and minl need to be analyzed and compared.

[0153] 1) When k1minl < cut4, grid division cannot be performed and the panel allocation needs to be redone, where k1 = 1.2;

[0154] 2) When k2minl ≤ cut4 ≤ k1minl, let cut4 = minl and perform grid division;

[0155] ① When cut4 < H i perform cutting and division according to the first cutting method, and the first cutting method is the cutting method corresponding to Figure 15 ;

[0156] ② When cut4 < H i and ratio > 5 / 8, perform cutting and division according to the second cutting method, and the second cutting method is the cutting method corresponding to Figure 16 ;

[0157] ③ When cut4 < H i and ratio < 5 / 8, perform cutting and division according to the third cutting method, and the third cutting method is the cutting method corresponding to Figure 17 ;

[0158] 3) When cut4 < k2minl, perform grid division;

[0159] ① When ratio > 5 / 8, perform cutting and division according to the first cutting method, as shown in Figure 15 ;

[0160] ② When ratio < 5 / 8, perform cutting and division according to the third cutting method, as shown in Figure 17 ;

[0161] Where: H i is the shortest side length of any surface

[0162] K1 = 1.2

[0163] k2 = 0.8

[0164] Hi is the minimum side length of any surface

[0165] ratio = H / L, the aspect ratio

[0166] minl is the shortest side length among all surfaces.

[0167] Furthermore, the process of endowing material properties again is as follows:

[0168] After the cutting operation on the above hot areas is completed, it is necessary to assign material properties to these cut surfaces again.

[0169] Endow surface properties: First, select the spatial geometric surface through a function, and then re-endow the surface with the information stored in the array of surface properties obtained through the material assignment function.

[0170] After the above operations are completed, the hot areas can be operated with refined grids and transition grids.

[0171] The results of batch meshing for the through double-ten surface, through eleven-surface, non-through cross surface, and non-through T-shaped surface are respectively as Figure 18 , Figure 19 , Figure 20 and Figure 21 shown.

[0172] Figure 18 is the mesh refinement diagram of the through double-ten surface;

[0173] Figure 19 is the mesh refinement diagram of the through eleven-surface;

[0174] Figure 20 In (a) is the front view of the mesh refinement of the non-through cross surface, and (b) is the bottom view of the mesh refinement of the non-through cross surface;

[0175] Figure 21 In (a) is the front view of the mesh refinement of the non-through T-shaped surface, and (b) is the bottom view of the mesh refinement of the non-through T-shaped surface;

[0176] Next, the invention results will be demonstrated with an example of an LNG compartment.

[0177] Figure 22 is the fine mesh model and local enlarged model at the connection between the bottom plate of the B-type compartment and the bottom support. The geometric structure of this model conforms to the non-through T-shaped surface;

[0178] Figure 23 In (a) is the front view of the refined model of the outer wall plate surface of the LNG B-type compartment, and (b) is the side view of the refined model of the outer wall plate surface of the LNG B-type compartment. The geometric structure of this model conforms to the non-through T-shaped surface.

[0179] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for fine-grained batch processing of straight-face cross-plate grids in fatigue hot spots, characterized in that: It includes the following steps: Based on the three-dimensional template of the straight cross plate, obtain the geometric dimension parameters of the straight cross plate; Based on the obtained geometric dimension parameters of the straight cross plate, identify the type of the hot spot area structure of the straight cross plate; The process of identifying the type of the hot spot area structure of the straight cross plate based on the obtained geometric dimension parameters of the straight cross plate includes two aspects: identifying whether the hot spot area structure contains an inclined plane and identifying the type of the hot spot area structure; The method used to identify the type of the hot spot area structure is to select a position in the space coordinate system, then determine the existence of a geometric plane in this space, and judge the type of the hot spot area structure according to the number of geometric planes; To identify whether the hot spot area structure contains an inclined plane, select each octant in turn through the space surface selection command, and check whether there is a plane in each octant. If it exists, it proves that there is an inclined plane in this structure; Perform batch grid refinement processing on the identified hot spot areas of the type; The batch grid refinement processing of the identified hot spot areas of the type includes the following steps: Surface cutting: After selecting the interface, a refined grid area with a thickness 10 times the surface thickness needs to be cut out according to the requirement of t×t, and then a transition grid area with a specific shape is cut out; Obtain material properties and reassign material properties: Select the space geometric plane through a function, then obtain the material properties of each space plane through a function, store the material properties in the surface property storage array, and reassign the properties to the surface according to the information obtained from the surface property storage array; The surface cutting: After selecting the interface, the process of cutting out a refined grid area with a thickness 10 times the surface thickness and then cutting out a transition grid area with a specific shape includes the following steps: Grid area division: First, determine the side length cut1 of the refined area according to the plate thickness and specifications, and divide the refined area rectangle; Then, according to the principle of smooth transition, divide four layers of transition grid areas, with side lengths cut2, cut3, cut6, and cut4 in turn, where the side length of the outermost area is set to cut4; Finally, process the connection relationship between the transition area grid and the first-layer geometric plane; Adjust the transition grid area.

2. The method for fine-grained batch processing of straight-face cross-plate grids in fatigue hot spots according to claim 1, characterized in that: The types of the hot spot area structures of the straight cross plate include: non-through cross surface, non-through T-shaped surface, through eleven-shaped surface, and through double-ten-shaped surface.

3. The method for fine-grained batch processing of straight-face cross-plate grids in fatigue hot spots according to claim 1, characterized in that: The process of obtaining the geometric dimension parameters of the straight cross plate based on the three-dimensional template of the straight cross plate is as follows: Taking the hot spot as the reference, obtain the distance length from the end point on the edge line segment of the geometric plane falling on the coordinate axis to the hot spot; The method of obtaining the distance length from the end point of the edge line segment to the hot spot is as follows: Determine the two direction positions in the radial direction of the line segment, and then increase the distance little by little in the axial direction of the line segment until the geometric midpoint of this line is selected, that is, this line segment is selected; Then select the straight line where the line segment is located; After selecting this straight line, the distance from the end point of this line segment to the coordinate origin can be obtained; The method of obtaining the dimensions of the Y-axis and Z-axis of the first layer is the same as the method of obtaining the dimension of the X-axis of a surface of the first layer; As needed, not only can the distance from the outer endpoint on the first layer to the hot spot be obtained, but also the first layer can be skipped to directly obtain the distance from the outer endpoint of the line segment on the second or third layer to the hot spot.

4. The method for fine-grained batch processing of straight-face cross-plate grids in fatigue hot spots according to claim 1, characterized in that: The functions and formulas for obtaining the geometric dimension parameters of the straight cross plate are as follows: *use,select_layer.mac,a,'b','c',d(1) Among them: the length of ▽ should depend on the actual length of the line segment; Formula (1) is the usage method of the function for obtaining geometric dimension parameters. Among the four parameters a, b, c, and d in the formula, a represents the layer number, which is an Arabic numeral; parameter b represents the axis name, and the three characters x, y, and z can be selected; parameter c represents the direction of the axis, and the two characters - and + can be selected; parameter d represents the inverted triangle in formula 4, which is the length increment and is a number; *use,select_layer.mac,2,'x','+',0.1 means that on the positive x-axis, the length of the distance from the outer endpoint of the upper line segment on the second layer to the hot spot is obtained, and it increases with an increment of 0.1; Formula (2) is the command stream for selecting a line segment in ANSYS software; Formula (3) is the explanation of the fifth and sixth parameters x1 and x2 in the first function in formula (2), where the inverted triangle is a number, named the length increment, which is one-tenth of the length of the selected line segment.

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