JP4907375B2 - Method for simulating the occurrence of air accumulation in an object to be immersed and a computer-executable program for executing the simulation method - Google Patents

Description

  The present invention relates to an air pool generation simulation method for an object to be immersed that simulates an air pool generated in an object to be immersed when immersed in a paint tank, and a program executable by a computer that executes the simulation method.

  An object to be dipped such as a vehicle body of a vehicle is dipped in a paint tank filled with a liquid paint so that the surface thereof is subjected to electrodeposition coating. According to such a coating method, the thickness of the coating film formed on the surface of the object to be immersed can be made substantially uniform, or a similar coating process can be applied to the welded portion of the object to be immersed. There are advantages such as. On the other hand, for example, in the case of a body body, a plurality of recesses are formed on the inner surface of the hood, the inner surface of the roof, the lower surface of the floor, etc. in the object to be immersed in a complicated shape, so that these recesses become an air pocket called an air pocket. In the state where the air in the air pool remains, there is a drawback that the portion cannot be painted.

  Therefore, for example, as shown in Patent Document 1, a discharge path for discharging air into the atmosphere is formed in advance in the object to be immersed so as not to cause air accumulation in the object to be immersed. Air is discharged into the atmosphere through a discharge path so that the entire surface of the object to be immersed can be subjected to a coating process.

The air pool generated in the object to be immersed can be simulated by a well-known analysis method using a free surface, and the design work is made efficient by designing the object to be immersed by reflecting this simulation result. You can do well. In the Japanese Patent Application No. 2006-180453, in order to reduce the time required for the simulation and to perform the design work more efficiently, the applicant of the present invention has not divided the numerical calculation model of the vehicle body into three-dimensional elements. An application has been filed for a method of simulating the occurrence of air pockets for each of the numerical calculation models for each member forming the vehicle body while being divided into dimension elements.
Japanese Patent Laid-Open No. 10-045037

  However, in the method of simulating the occurrence of air accumulation for each member forming the vehicle body as described above, it is possible to simulate a connection member formed by connecting one member and another member as an analysis target. could not. That is, for example, for connection members that are connected so that the ends of one member and the other member open downward in the dipping direction so that the cross-section has a square shape (saddle shape) However, according to the above simulation method, each member is individually simulated without defining the connection relationship between the members. The problem of misjudging such as “z” could occur.

  It is an object of the present invention to define a connection relationship between one member and another member, generate connection member data, and simulate the occurrence of air accumulation based on the connection member data. An object of the present invention is to provide an air pool generation simulation method and a program executable by a computer that executes the simulation method.

The method for simulating the occurrence of air stagnation in an object to be immersed in the present invention is a simulation of the occurrence of air stagnation in an object to be immersed in the object to be processed, which simulates the air stagnation generated in the object to be immersed in immersion in the paint tank using a fluid analyzer The method includes: a first step of dividing shape data of one member and another member forming the object to be immersed into a plurality of two-dimensional elements by the control unit of the fluid analysis device ; A second step of calculating a centroid point of an element forming each member; a third step of determining a distance between the centroid points of the elements of each member and determining whether the members are within a predetermined distance from each other; And a fourth step of generating copy data of each member having the same information as each member after determining that the distance is within a predetermined distance in the third step and the third step. And a fifth step of generating normal vectors extending in opposite directions from the elements forming the original data and copy data of each member, and the normal vectors are the elements of the members And a sixth step for determining whether or not they penetrate each other, and after determining that they penetrate each other in the sixth step, each element having a normal vector that penetrates is set as an adjacent element, and each of the members Among the elements forming the connecting member connected in the seventh step, an element located at an end or a hole is set as an initial boundary element, and the initial boundary element An eighth step of setting an element sharing a node as an adjacent element; and the attribute of the adjacent element set in the eighth step is determined by air using the initial boundary element. A ninth step of analyzing whether the paint is a paint, and the adjacent element that has been analyzed in the ninth step as a secondary boundary element, and an element sharing a node with the secondary boundary element A tenth step of setting an adjacent element, and an eleventh step of analyzing whether the attribute of the adjacent element set in the tenth step is air or paint using the secondary boundary element And if there is an adjacent element adjacent to the secondary boundary element, and if it is determined that there is an adjacent element adjacent to the secondary boundary element, the adjacent element adjacent to the secondary boundary element The process of each step is repeated in the order of the tenth step and the eleventh step until there is no more, and the analysis is terminated when it is determined that there is no adjacent element adjacent to the secondary boundary element. And 12 steps are executed .

  In the method for simulating the occurrence of air stagnation in the object to be immersed according to the present invention, in the ninth step and the eleventh step, the initial boundary element, the secondary boundary element, and the adjacent element are separated from the center of gravity of each element. If the height of the center of gravity of the initial boundary element or the secondary boundary element is higher than the height of the center of gravity of the adjacent element, it is determined that the attribute of the adjacent element is paint. When the height of the center of gravity of the initial boundary element or the secondary boundary element is lower than the height of the center of gravity of the adjacent element, it is determined that the attribute of the adjacent element is air.

  In the method for simulating the occurrence of air accumulation in the object to be immersed according to the present invention, the object to be immersed is a vehicle body.

  The computer-executable program for executing the method for simulating the occurrence of air stagnation in the object to be immersed according to the present invention is an air stagnation in the object to be immersed that simulates the air stagnation generated in the object to be immersed when immersed in the paint tank. A computer-executable program for executing the generation simulation method, the first step of dividing the shape data of one member and the other member forming the object to be immersed into a plurality of two-dimensional elements; The second step of calculating the center of gravity of the elements forming each member and the distance between the centers of gravity of the elements of each member are determined to determine whether or not the members are within a predetermined distance from each other. Each unit having the same information as each member after determining that it is within a predetermined distance in the third step and the third step A fourth step of generating the copy data of the above, a fifth step of generating normal vectors extending in opposite directions from elements forming the original data and copy data of each member, and the normal vector However, the sixth step of determining whether or not the elements of each member penetrate each other, and the elements having normal vectors that penetrate each other after determining that the elements penetrate each other in the sixth step. Among the elements that are adjacent to each other and connect the respective members, and the elements that form the connecting members connected in the seventh step, the element located at the end or hole is set as the initial boundary element And an eighth step of setting an element sharing a node with the initial boundary element as an adjacent element, and an attribute of the adjacent element set in the eighth step A ninth step of analyzing whether it is air or paint using the initial boundary element, and setting the adjacent element analyzed in the ninth step as a secondary boundary element, and A tenth step of setting an element that shares a node with the next boundary element as an adjacent element, and an attribute of the adjacent element set in the tenth step is air or paint using the secondary boundary element The eleventh step of analyzing whether or not there is an adjacent element adjacent to the secondary boundary element, and if it is determined that there is an adjacent element adjacent to the secondary boundary element, The process of each step is repeated in the order of the tenth step and the eleventh step until there is no adjacent element adjacent to the secondary boundary element, and there is no adjacent element adjacent to the secondary boundary element. And a twelfth step of ending the analysis when it is determined.

  The computer-executable program for executing the method for simulating the occurrence of air accumulation in the object to be immersed according to the present invention includes the initial boundary element and the secondary boundary element in the ninth step and the eleventh step, If the height of the centroid of the initial boundary element or the secondary boundary element is higher than the height of the centroid of the adjacent element, the height of the centroid of the initial boundary element or the secondary boundary element is compared with the adjacent element. If the height of the center of gravity of the initial boundary element or the secondary boundary element is lower than the height of the center of gravity of the adjacent element, it is determined that the attribute of the adjacent element is air. It is characterized by doing.

  The computer-executable program for executing the simulation method for generating air stagnation in the object to be immersed according to the present invention is characterized in that the object to be immersed is a vehicle body.

According to the method for simulating the occurrence of air accumulation in the object to be submerged according to the present invention, the control unit of the fluid analysis apparatus determines the connection relationship between one member and another member, the distance between the center of gravity of each member element, and the normal vector. Is defined from the setting of the elements that penetrate each other, and the occurrence of air pools is simulated for the connection member formed by connecting each member, so that each individual member to be connected is a single connection member It can be analyzed. In this case, since the data of the connection member includes original data and copy data, for example, one of the data can be set to the front side and the other side can be set to the back side. Thus, it is possible to accurately simulate the occurrence of air pockets.

  According to the method for simulating the occurrence of air accumulation in the object to be immersed according to the present invention, the height of the center of gravity of the two-dimensional elements sharing the nodes is compared to determine whether it is air or paint. It is possible to quickly determine whether or not air accumulation occurs.

  According to the method for simulating the occurrence of air accumulation in the object to be immersed according to the present invention, the object to be immersed can be the vehicle body, and in this case, the occurrence of air accumulation in the body body having a complicated shape can be simulated. .

  According to the computer-executable program for executing the simulation method for generating air stagnation in the object to be immersed according to the present invention, the computer can execute the simulation method for generating stagnation of air in the object to be immersed according to the present invention. .

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a block diagram of a fluid analyzing apparatus that executes a simulation method according to the present invention.

  As shown in FIG. 1, a fluid analysis device (computer) 10 that executes a method for simulating the occurrence of air accumulation in an object to be immersed according to the present invention includes a keyboard 11 for inputting analysis conditions of the object to be immersed, an analysis process, and the like. Display 12 for displaying the results, HDD (hard disk drive) 13 for storing various data of the object to be immersed, and FDD (flexible disk drive) 14 for storing the results of analysis processing in FD (flexible disk) And have.

  The fluid analysis apparatus 10 further includes a control unit 18 including a CPU 15, ROM 16 and RAM 17, a keyboard controller 19 of the keyboard 11, a display controller 20 of the display 12, a disk controller 21 of the HDD 13 and the FDD 14, and a fluid analysis apparatus. A network interface controller 23 for connecting 10 to the network 22 is provided, and these can communicate with each other via a system bus 24.

  The CPU 15 constituting the control unit 18 executes the software stored in the ROM 16 and the HDD 13 or the software supplied from the FDD 14 so as to comprehensively control various components connected to the system bus 24. It has become. That is, the CPU 15 reads out software from the ROM 16, HDD 13, or FDD 14 according to a predetermined processing sequence, and executes the program to perform control for realizing the operations shown in FIGS. 8 and 11.

  CPU15 reads the various data of the to-be-immersed processing object used as analysis object from HDD13, and constructs the two-dimensional numerical calculation model divided | segmented into several elements from this read-out various data. Further, the CPU 15 calculates information (data) necessary for realizing the operations shown in FIGS. 8 and 11 based on the constructed numerical calculation model, that is, calculates the center of gravity of an element, sets adjacent elements, and the like. This is performed, and finally, the state of occurrence of air accumulation in the object to be immersed is displayed on the display 12.

  The RAM 17 constituting the control unit 18 functions as a main memory or work area for the CPU 15. The keyboard controller 19 controls input signals from input means such as the keyboard 11 and a pointing device (not shown), and the display controller 20 controls display on the display 12. The disk controller 21 controls access to the HDD 13 and the FDD 14 that store or read a boot program, various applications, editing files, user files, network management programs, and the like. The network interface controller 23 transmits and receives data to and from other devices (not shown) on the network 22.

  The air pool generation simulation method for the object to be immersed according to the first embodiment simulates the air pool generated in the vehicle body during the electrodeposition coating of the vehicle body such as a passenger car. First, a painting line for a vehicle body will be described with reference to FIG.

  FIG. 2 is an explanatory view for explaining a painting line for a vehicle body. A vehicle body 30 as an object to be dipped is a plurality of vehicle body panel members (FIG. 2) including a floor panel member, a side panel member, a roof panel member, and the like. (Not shown) are joined by spot welding or the like. The vehicle body 30 is transported in a substantially horizontal direction on the coating line 33 while being hung on a hanger 32 of a transport device 31.

  A pre-processing line (not shown) is provided in the front stage of the coating line 33 of the conveying device 31. In this pre-processing line, the body 30 is subjected to hot water washing and degreasing as a pre-treatment for electrodeposition coating. , Water washing, surface conditioning, film formation, water washing, and drying are successively performed in this order. After finishing the treatment in this pretreatment line, the vehicle body 30 moves to the painting line 33 and descends toward the electrodeposition tank (paint tank) 34 and is completely immersed in the electrodeposition solution (paint) 35. It moves in a substantially horizontal direction in the state. Under this state, a predetermined thickness of voltage is applied to the body 30 and electrodes (not shown) in the electrodeposition tank 34 to deposit a coating film having a predetermined thickness on the surface of the body 30. Can be made. Thereafter, the vehicle body 30 is pulled up from the electrodeposition tank 34 by the transfer device 31 and the excess electrodeposition solution 35 adhering to the vehicle body 30 without being electrodeposited is removed by washing or the like.

  Next, a method for simulating the occurrence of air accumulation in the object to be immersed according to the first embodiment will be described in detail. In the first embodiment, the finite element method is used as an analysis method, and the analysis is performed on the floor panel member constituting the vehicle body 30 as an analysis target.

  FIG. 3 is an explanatory view for explaining a numerical calculation model of a floor panel member in the vehicle body.

  The control unit 18 (see FIG. 1) of the fluid analysis apparatus 10 uses the shape data of the floor panel member 40 in the vehicle body 30 shown in FIG. 3 as a plurality of two-dimensional elements 41 (see broken line circle A part) formed by planes. In order to construct this two-dimensional numerical calculation model, for example, a numerical calculation model used in a collision deformation simulation of the vehicle body 30 may be used. it can.

  The floor panel member 40 is formed by joining the first panel 40a as one member and the second panel 40b as another member by a joining means such as spot welding, as shown in the broken line circle A part, First, the control unit 18 defines the mutual welded portions WP in each of the panels 40a and 40b, that is, finds the joint relationship between the panels 40a and 40b.

  Here, in 1st Embodiment, the case where the edge part vicinity (edge part vicinity) of each panel 40a, 40b is mutually joined is shown, and hereafter, it uses the model shown in FIG. 4 and FIG. explain. FIG. 4 is a simplified model diagram showing a simplified shape of each panel in the first embodiment, and FIG. 5 is a schematic diagram schematically showing elements in a broken line circle B portion of FIG.

  As shown in FIG. 4, the 1st panel 40a and the 2nd panel 40b form the floor panel member 40 by joining the edge part vicinity through the welding part WP, Each panel 40a, 40b They are joined so as to be inclined at a predetermined angle. Each panel 40a, 40b is opened to the upper side in the figure with respect to the immersion direction in the electrodeposition tank 34 shown in FIG.

  As shown in the schematic diagram of FIG. 5, the first panel 40a is composed of elements A, B, C, and D, and the second panel 40b is composed of elements E, F, G, and H. Each of the elements A to H is formed by a plane having four nodes. The shape data (pre-update data) of these elements A to H is represented as shown in FIG. Each node a to t forming each element A to H has coordinate data (X coordinate value, Y coordinate value, Z coordinate value), and the coordinate data (update) of each node a to t. The previous data) is expressed as shown in FIG. FIG. 6 shows the shape data before updating each element, and FIG. 7 shows the coordinate data of each node.

  The element A forming the first panel 40a has a free edge 40c (broken line in FIG. 5) formed by connecting the node a to the node f, and its adjacent elements share the node b and the node g. B. The element H forming the second panel 40b has a free edge 40d (broken line in FIG. 5) formed by connecting the node o and the node t, and its adjacent elements share the node n and the node s. Element G to be

  These elements A and H are mutually defined as a welded part WP when the control unit 18 of the fluid analyzing apparatus 10 executes the flowchart shown in FIG. Hereinafter, based on FIGS. 8-10, the definition method of joining of each panel 40a, 40b by the control part 18 is demonstrated. FIG. 8 is a flowchart showing an analysis process for defining the bonding of each panel, FIGS. 9A, 9B, and 9C are explanatory diagrams for explaining the processing contents of the flowchart of FIG. 8, and FIG. The updated data corresponding to FIG. 6 is shown. In the following description with reference to FIGS. 8 and 9, the first panel 40a and the second panel 40b will be described as the first panel (PA) and the second panel (PB), respectively.

  As shown in FIG. 8, first, when power is supplied to the fluid analysis device 10 and power is supplied to the control unit 18, initial setting of the control unit 18 is performed and software for analysis processing from the HDD 13 or the like to the RAM 17 is performed. Is read and a program (bonding definition program) for executing the method for simulating the occurrence of air accumulation in the object to be immersed according to the present invention is executed (step S1).

  Next, the operator inputs the first panel (PA) and the second panel (PB) whose bonding should be defined through the keyboard 11 (step S2).

  In the subsequent step S3, the original data corresponding to the input first panel (PA) and second panel (PB), that is, shape data (diversion data) used for the collision deformation simulation of the vehicle body 30 is read from the HDD 13. read out. Then, the read shape data of the first panel (PA) and the second panel (PB) is divided into a plurality of two-dimensional elements. Thereafter, the data (pre-update data) shown in FIGS. 6 and 7 generated in this division processing is stored in the RAM 17 to construct a numerical calculation model. Here, step S3 constitutes a first step of the present invention.

  In step S4, the free edge elements (FAM_A) and (FBM_H) of the panels (PA) and (PB), that is, the centroid points (AG_A) and (AG) at the elements A and H having the free edges 40c and 40d shown in FIG. BG_H) is calculated (see FIG. 9A). The barycentric points (AG_A) and (BG_H) are subjected to a predetermined calculation using the coordinate data of the nodes a, b, f and g forming the element A and the nodes n, o, s and t forming the element H. Is calculated by Here, step S4 constitutes a second step of the present invention.

  In step S5, it is determined whether the gravity center points (AG_A) and (BG_H) calculated in step S4 are within a predetermined distance from each other, and it is determined that they are within a predetermined distance, that is, each panel (PA), If it is determined (yes) that the members (PB) are close to each other, the process proceeds to step S6. On the other hand, if it is determined that the panels (PA) and (PB) are separated by a predetermined distance or more, that is, if it is determined that the panels (PA) and (PB) are separated from each other (no), step S7 is performed. Proceed to The distance between the centroid points (AG_A) and (BG_H) is calculated by performing a predetermined calculation using the coordinate data of each centroid point. Here, step S5 constitutes a third step of the present invention.

  In step S7, since the panels (PA) and (PB) are separated members, the respective members are not joined to each other, that is, the panels (PA) and (PB) are assumed to be “non-welded members”. In step S8, for example, “the input member is not joined” is externally displayed via the display 12. Thereafter, in step S9, the joint definition analysis process ends.

  In step S6, copy panels (PA) 'and (PB)' for the panels (PA) and (PB) are generated (see FIG. 9B). Each copy panel (PA) ′, (PB) ′ has the same information (copy data) as the shape data forming each panel (PA), (PB), and as shown in FIG. Is generated based on pre-update data (original data) shown in FIG. However, the memory address, element number, node number, and adjacent element number corresponding to the shape data of the copy panels (PA) 'and (PB)' are different from those of the original data. As described above, the shape data corresponding to the copy panels (PA) 'and (PB)' is generated and stored in the RAM 17, and then the process proceeds to step S10. Here, step S6 constitutes a fourth step of the present invention.

  In step S10, the free edge elements (FAM_A) and (FBM_H) formed by the original data and the free edge elements (FAM_A) ′ and (FBM_H) ′ formed by the copy data are contradictory on the original side and the copy side. Normal vectors (AL_A), (BL_H), (AL_A) ′, (BL_H) ′ extending in the direction are generated (see FIG. 9C).

  Each normal vector (AL_A), (BL_H), (AL_A) ', (BL_H)' is the center of gravity (AG_A) at each free edge element (FAM_A), (FBM_H), (FAM_A) ', (FBM_H)' ), (BG_H), (AG_A) ', and (BG_H)' are used to perform a predetermined calculation and extend from each centroid point (AG_A), (BG_H), (AG_A) ', (BG_H)' Generate as follows. Also, normal vectors extending in opposite directions are generated by setting one to be positive and the other to be negative on the original side and the copy side. In generating the normal vector, a normal vector extending from an arbitrary part of each free edge element is generated by performing a predetermined calculation using the coordinate data of each node forming each free edge element. Anyway. Here, step S10 constitutes the fifth step of the present invention.

  In step S11, the normal vectors (AL_A), (BL_H), (AL_A) ′, and (BL_H) ′ generated in step S10 are elements on the first panel (PA) side and second panel (PB) side, respectively. It is determined whether or not they penetrate each other. That is, as shown in FIG. 9C, whether or not the normal vector (AL_A) ′ passes through the free edge element (FBM_H) and the normal vector (BL_H) passes through the free edge element (FAM_A) ′. Determine whether.

  In step S11, if it is determined that they penetrate each other (yes), the process proceeds to step S12. If it is determined that they do not penetrate each other (no), the process proceeds to step S13. Note that whether or not to penetrate is determined by whether or not the intersection of a normal vector and an element (a plane defined by four nodes) is calculated. Here, step S11 constitutes a sixth step of the present invention.

  In step S13, although the panels (PA) and (PB) are members close to each other, for example, in FIG. 9C, the panels (PA) and (PB) are separated from each other in the horizontal direction in the drawing. In the case where they do not overlap in the vertical direction (no determination in step S11), the panels (PA) and (PB) are regarded as “non-welded members”, and in the subsequent step S14, for example, “ "The input members will not be joined." Thereafter, in step S15, the analysis process of the connection definition is terminated.

  In step S12, the panels (PA) and (PB) are finally joined to each other, that is, the panels (PA) and (PB) are welding members, and the process proceeds to the next step S16.

  In step S16, the free edge element (FAM_A) 'of the copy panel (PA)' is set as an adjacent element of the free edge element (FBM_H) of the panel (PB), and the free edge element (FBM_H) of the panel (PB) is set. Set to the adjacent element of the free edge element (FAM_A) of the copy panel (PA). Then, as indicated by the white arrow in FIG. 10, the adjacent element number is updated and stored in the RAM 17. Then, as shown in FIG. 10, the control unit 18 updates the adjacent element number, and stores the analysis result of the joint definition in the HDD 13 with the original data and the copy data as the analysis target members I to III, respectively. Here, step S16 constitutes the seventh step of the present invention.

  In the subsequent step S17, for example, “the input member is joined” is externally displayed on the display 12, and then the joining definition analysis processing is terminated in step S18. In this manner, the joint between the first panel (PA) and the second panel (PB) is defined, and each panel (PA), (PB) can be associated on the data as a connection member.

  Next, based on FIG. 11 and FIG. 12, a method for determining whether or not an air pocket is generated that is executed after the analysis processing of the joint definition shown in FIG. 8 will be described. FIG. 11 is a flowchart showing an analysis process for determining the occurrence of air pockets, and FIGS. 12A, 12B, and 12C are explanatory diagrams for explaining the processing contents of the flowchart of FIG. .

  As shown in FIG. 11, first, analysis processing software is read from the HDD 13 or the like into the RAM 17, and a program (air pool determination program) for executing the air pool generation simulation method for the object to be immersed according to the present invention is executed. (Step S20).

  Next, among the shape data of analysis target members I to III (see FIGS. 10 and 12) as connection members generated in the joint definition program shown in FIG. 8, one of the analysis target members (P_i) The shape data is called into the RAM 17 by the operation of the operator's keyboard 11 (step S21).

  In step S22, all elements forming the analysis target member (P_i) called to the RAM 17 are set to air as an initial state. In this way, by setting all elements forming the analysis target member (P_i) as air in the initial state, the surroundings of the analysis target member (P_i) before the vehicle body 30 is immersed in the electrodeposition tank 34, Simulates a state filled with air.

  In step S23, the immersion direction of the vehicle body 30 in the electrodeposition tank 34, that is, the gravitational direction (G) of the analysis target member (P_i) is input by operating the keyboard 11 of the operator. And the control part 18 updates the coordinate data (refer FIG. 7) of the node in all the elements which form the analysis object member (P_i) based on the input gravity direction (G), and this gravity direction (G) The considered coordinate data (updated data) is stored in the RAM 17.

  In step S24, in the case of the free edge element (FM_i) existing at the end or hole of the analysis target member (P_i), that is, the analysis target member II (connection member defined to be joined) in FIG. Element (BM_E) and element (AM_D) ′ correspond to free edge elements (FM_i), and these elements (BM_E) and (AM_D) ′ are set as initial boundary elements. Hereinafter, description will be given based on the analysis target member II.

  In step S25, the nodes of the initial boundary elements (BM_E) and (AM_D) ′ set in step S24 are shared, and the adjacent elements (NM_i) to be compared with the initial boundary elements (BM_E) and (AM_D) ′, that is, The element (BM_F) and the element (AM_C) ′ shown in FIG. 12B correspond to the adjacent elements (NM_i), and these elements (BM_F) and (AM_C) ′ are set as the adjacent elements. Here, step S24 and step S25 constitute the eighth step of the present invention.

  In step S26, the centroid points (BG_E) and (AG_D) 'of the elements (BM_E) and (AM_D)' set as the initial boundary elements in step S24 are calculated, and the elements ( The centroid points (BG_F) and (AG_C) ′ of BM_F) and (AM_C) ′ are calculated, and the heights of the centroid points are compared based on the Z coordinate values.

  After that, in step S27, it is determined that the barycentric point (BG_E) is lower than the barycentric point (BG_F), and the attribute of the element (BM_F) which is an adjacent element is left as air and the attribute is not changed. On the other hand, it is determined that the barycentric point (AG_D) 'is higher than the barycentric point (AG_C)', and the attribute of the element (AM_C) 'which is an adjacent element is changed from air to liquid (paint). Here, step S27 constitutes a ninth step of the present invention.

  In step S28, the adjacent elements (BM_F) and (AM_C) ′ that have been compared with the initial boundary elements (BM_E) and (AM_D) ′ are set as secondary boundary elements, and then newly set in step S29. It is determined whether there are adjacent elements (NM_j) adjacent to the secondary boundary elements (BM_F) and (AM_C) ′. Here, step S28 and step S29 constitute the tenth step of the present invention.

  In step S29, when it is determined (no) that there is no adjacent element (NM_j) adjacent to the secondary boundary element (BM_F), (AM_C) ′, the process proceeds to step S30 and, for example, the determination result is displayed via the display 12. The external display is performed by graphic display or the like, and the analysis process of the air pocket determination is terminated.

  In step S29, when it is determined (yes) that there is an adjacent element (NM_j) adjacent to the secondary boundary element (BM_F), (AM_C) ', that is, adjacent to the secondary boundary element (BM_F), (AM_C)' If the element (BM_G), (AM_B) ′ is found, the process proceeds to step S31.

  In step S31, the barycentric points (BG_G) and (AG_B) 'of the adjacent elements (BM_G) and (AM_B)' found in step S29 are calculated, and each element (BM_F) set as the secondary boundary element in step S28. ), (AM_C) 'and the center of gravity (BG_F), (AG_C)' and the center of gravity (BG_G), (AG_B) 'calculated in step S31 are compared based on their respective Z-coordinate values. To do.

  In step S32, it is determined that the barycentric point (BG_F) is lower than the barycentric point (BG_G), and the attribute of the adjacent element (BM_G) is left as air and the attribute is not changed. On the other hand, it is determined that the barycentric point (AG_C) 'is higher than the barycentric point (AG_B)', and the attribute of the element (AM_B) 'which is an adjacent element is changed from air to liquid (paint). Here, step S31 and step S32 constitute the eleventh step of the present invention.

  In the subsequent step S33, the adjacent elements (BM_G) and (AM_B) ′ that have been compared with the secondary boundary elements (BM_F) and (AM_C) ′ are set as secondary boundary elements. It is determined whether there are adjacent elements (NM_k) adjacent to the set secondary boundary elements (BM_G) and (AM_B) ′. Here, Step S33 and Step S34 constitute the tenth step of the present invention.

  In step S34, when it is determined (no) that there is no adjacent element (NM_k) adjacent to the secondary boundary element (BM_G), (AM_B) ′, the process proceeds to step S30 and, for example, the determination result is displayed via the display 12. The external display is performed by graphic display or the like, and the analysis process of the air pocket determination is terminated.

  In step S34, when it is determined (yes) that there is an adjacent element (NM_k) adjacent to the secondary boundary element (BM_G), (AM_B) ', that is, adjacent to the secondary boundary element (BM_G), (AM_B)' When the elements (FBM_H) and (FAM_B) ′ are found, the process returns to step S31.

  In step S31, the center of gravity (FBG_H), (FAG_A) 'of each adjacent element (FBM_H), (FAM_B)' found in step S34 is calculated, and each element (BM_G) set as the secondary boundary element in step S33. ), (AM_B) 'and the center of gravity (BG_G), (AG_B)' and the center of gravity (FBG_H), (FAG_A) 'calculated in step S31 are compared based on their respective Z coordinate values. To do.

  As described above, the control unit 18 repeats the comparison process for comparing the heights of the center of gravity points of the initial boundary element and the secondary boundary element with the adjacent elements, and the element attribute determination process based on the comparison result. The analysis process is repeated until there are no adjacent elements adjacent to the secondary boundary element. Here, the repeated analysis processing in steps S31 to S34 constitutes the twelfth step of the present invention.

  Here, the attribute determination of all elements constituting the analysis target member II shown in FIG. 12B will be described. The element attributes from the element (BM_E) side (the left side in the figure) are changed with air. On the other hand, the attribute from the element (AM_D) ′ side (right side in the figure) is changed from air to liquid. Therefore, along with the attribute change (air to liquid) from the element (AM_D) 'side, the attributes of all the elements constituting the analysis target member II are changed to liquid (paint), and thus the analysis target member II has air. It is determined that no accumulation occurs.

  The analysis target member I (original of the first panel (PA)) and the analysis target member III (copy of the second panel (PB)) shown in FIGS. 12 (a) and 12 (c) are subjected to the same steps. Similarly, the analysis process is performed, and it is determined that neither the analysis target member I nor the analysis target member III has an air reservoir.

As described in detail above, according to the simulation method for the occurrence of air accumulation in the object to be immersed according to the first embodiment, the control unit 18 of the fluid analysis device 10 performs the first panel (PA) and the second panel (PB). ), The distance of the center of gravity (AG_A), (BG_H) of the free edge elements (FAM_A), (FBM_H) of each panel (PA), (PB) and the normal vector (AL_A) ', (BL_H) Is defined from the setting of adjacent elements of the free edge elements (FAM_A) and (FBM_H) that pass through, and simulates the occurrence of air pockets for the connection members formed by connecting each panel (PA) and (PB) Therefore, the individual panels (PA) and (PB) to be connected can be analyzed as one connecting member.

  In this case, since the data of each connected panel (PA), (PB) has original data and copy data, for example, one side of the original data and copy data is set to the front side and the other side is set to the back side. Therefore, the occurrence of air pockets can be accurately simulated on the front side and the back side of each connected panel (PA), (PB).

  Further, according to the simulation method for the occurrence of air accumulation in the object to be immersed according to the first embodiment, the height of the center of gravity of the two-dimensional elements sharing the nodes is compared to determine whether it is air or liquid (paint). By doing so, it is possible to quickly determine whether or not air accumulation occurs in each of the connected panels (PA) and (PB).

  Furthermore, according to the simulation method of the air accumulation occurrence in the object to be immersed according to the first embodiment, since the floor panel member that forms the vehicle body 30 is used as the object to be immersed in the body body 30 having a complicated shape. Generation of air pockets can be simulated.

  Next, a second embodiment of the present invention will be described in detail with reference to FIGS. The same parts as those in the first embodiment described above will be described with the same reference numerals.

  In the second embodiment, a case where the end of the second panel 40b is joined to a portion excluding the end of the first panel 40a (for example, the central portion of the first panel 40a) is shown. 13 and the model shown in FIG. FIG. 13 is a simplified model diagram showing a simplified shape of each panel in the second embodiment, and FIG. 14 is a schematic diagram schematically showing elements in a broken line circle C portion of FIG.

  As shown in FIG. 13, the panels 40a and 40b are joined so as to be inclined at a predetermined angle with each other, and form a gas-liquid boundary surface indicated by a broken line in the drawing when immersed in the electrodeposition tank 34 shown in FIG. That is, an air pocket is generated. Here, the gas-liquid boundary surface is a boundary surface between the air on the upper side in the drawing and the liquid (paint) on the lower side in the drawing.

  As shown in the schematic diagram of FIG. 14, the shape data (data before update) of the elements A to H forming the first panel 40a and the second panel 40b is represented as shown in FIG. The coordinate data (pre-update data) of the nodes a to t forming A to H is expressed as shown in FIG. FIG. 15 shows shape data before update of each element according to the second embodiment, and FIG. 16 shows coordinate data of each node according to the second embodiment.

  The element E forming the second panel 40b has a free edge 40e (broken line in FIG. 14) formed by connecting the node k and the node p, and its adjacent elements share the node l and the node q. F. Note that there is no free edge as described above in the vicinity of the element E of the second panel 40b in the first panel 40a.

  As for each panel 40a, 40b, when the control part 18 of the fluid analysis apparatus 10 performs the flowchart shown in FIG. 17, the welding part WP of each panel 40a, 40b is defined. Hereinafter, based on FIGS. 17-19, the definition method of joining of each panel 40a, 40b by the control part 18 is demonstrated. FIG. 17 is a flowchart showing an analysis process for defining the bonding of each panel according to the second embodiment, and FIGS. 18A to 18F are explanatory diagrams for explaining the processing contents of the flowchart of FIG. FIG. 19 shows post-update data corresponding to FIG. In the description of FIGS. 17 and 18, the first panel 40a and the second panel 40b will be described as the first panel (PA) and the second panel (PB), respectively.

  As shown in FIG. 17, first, when the fluid analyzing apparatus 10 is turned on and power is supplied to the control unit 18, initial setting of the control unit 18 is performed and software for analysis processing from the HDD 13 or the like to the RAM 17 is performed. Is read, and a program (bonding definition program) for executing the method for simulating the occurrence of air accumulation in the object to be immersed according to the present invention is executed (step S40).

  Next, the operator inputs the first panel (PA) and the second panel (PB) whose bonding should be defined through the keyboard 11 (step S41).

  In the subsequent step S42, the original data corresponding to the input first panel (PA) and second panel (PB), that is, the shape data (diversion data) used for the collision deformation simulation of the vehicle body 30 is read from the HDD 13. read out. Then, the read shape data of the first panel (PA) and the second panel (PB) is divided into a plurality of two-dimensional elements. Thereafter, the data (pre-update data) shown in FIGS. 15 and 16 generated in this division processing is stored in the RAM 17 to construct a numerical calculation model. Here, step S42 constitutes a first step of the present invention.

  In step S43, the center of gravity (BG_E) of the free edge element (FBM_E) of the second panel (PB), that is, the element E having the free edge 40e shown in FIG. 14 is calculated (see FIG. 18 (a)). The barycentric point (BG_E) is calculated by performing a predetermined calculation using the coordinate data of the nodes k, l, p, and q forming the element E.

  In step S44, centroids (AG_A to D) of all elements (AM_A to D) forming the first panel (PA) are calculated (see FIG. 18A). Each barycentric point (AG_A to D) is calculated by performing a predetermined calculation using the coordinate data of the nodes a to j forming the elements A to D shown in FIG. Here, step S43 and step S44 constitute the second step of the present invention.

  In step S45, the centroid point (BG_E) of the free edge element (FBM_E) calculated in step S43 is the centroid point (AG_A to D) of all the elements (AM_A to D) of the first panel (PA). It is determined whether or not each panel (PA), (PB) is within a predetermined distance, and is determined to be within the predetermined distance, that is, each panel (PA), ( If it is determined that the members PB) are close to each other (yes), the process proceeds to step S46. Here, as shown in FIG. 18A, it is determined that the element (AM_C) of the first panel (PA) is within a predetermined distance from the free edge element (FBM_E).

  On the other hand, if it is determined that the panels (PA) and (PB) are separated by a predetermined distance or more, that is, if the panels (PA) and (PB) are determined to be members separated from each other (no), step S47 is performed. Proceed to The distance between the centroid points is calculated by performing a predetermined calculation using the coordinate data of each centroid point. Here, step S45 constitutes a third step of the present invention.

  In step S47, since each panel (PA), (PB) is a distant member, each member is not joined to each other, that is, each panel (PA), (PB) continues as “non-welded member”. In step S48, for example, “the input member is not joined” is externally displayed on the display 12. Thereafter, in step S49, the analysis process of the connection definition is terminated.

  In step S46, copy panels (PA) 'and (PB)' for the panels (PA) and (PB) are generated (see FIG. 18B). Each copy panel (PA) ′, (PB) ′ has the same information (copy data) as the shape data forming each panel (PA), (PB), and as shown in FIG. Is generated based on pre-update data (original data) shown in FIG. However, the memory address, element number, node number, and adjacent element number corresponding to the shape data of the copy panels (PA) 'and (PB)' are different from those of the original data. In this way, the shape data corresponding to each copy panel (PA) ', (PB)' is generated and stored in the RAM 17, and the process proceeds to step S50. Here, step S46 constitutes a fourth step of the present invention.

  In step S50, the free edge element (FBM_E) formed from the original data and the element (AM_C) of the first panel (PA), and the free edge element (FBM_E) ′ formed from the copy data and the copy panel (PA) Normal vectors (AL_C), (BL_E), (AL_C) ', (BL_E)' extending in opposite directions on the original side and the copy side are generated from 'element (AM_C)' (FIG. 18 (c)). reference).

  Each normal vector (AL_C), (BL_E), (AL_C) ', (BL_E)' is the center of gravity (AG_C) at each element (AM_C), (FBM_E), (AM_C) ', (FBM_E)', Perform a predetermined calculation using the coordinate data of (BG_E), (AG_C) ', (BG_E)' so that it extends from each center of gravity (AG_C), (BG_E), (AG_C) ', (BG_E)' Generate. Also, normal vectors extending in opposite directions are generated by setting one to be positive and the other to be negative on the original side and the copy side. In generating the normal vector, a normal vector extending from an arbitrary part of each free edge element is generated by performing a predetermined calculation using the coordinate data of each node forming each free edge element. Anyway. Here, step S50 constitutes a fifth step of the present invention.

  In step S51, the normal vectors (AL_C), (BL_E), (AL_C) ′, and (BL_E) ′ generated in step S50 are elements on the first panel (PA) side and second panel (PB) side, respectively. It is determined whether or not they penetrate each other. That is, as shown in FIG. 18D, whether or not the normal vector (AL_C) ′ passes through the free edge element (FBM_E) and the normal vector (BL_E) passes through the element (AM_C) ′. judge.

  In step S51, if it is determined that they penetrate each other (yes), the process proceeds to step S52. If it is determined that they do not penetrate each other (no), the process proceeds to step S53. Note that whether or not to penetrate is determined by whether or not the intersection of a normal vector and an element (a plane defined by four nodes) is calculated. Here, step S51 constitutes a sixth step of the present invention.

  In step S53, although the panels (PA) and (PB) are members close to each other, it is assumed that the joining of the second panel (PB) to the first panel (PA) may be vertical, and subsequent step S54. For example, the display 12 externally displays, for example, “The input member cannot be defined to be joined”. Thereafter, in step S55, the analysis process of the connection definition is terminated. Here, each member to be actually joined is hardly judged as in step S53, and there is no practical problem.

  In step S52, the panels (PA) and (PB) are finally joined to each other, that is, the panels (PA) and (PB) are welding members, and the process proceeds to the next step S56.

  In step S56, the element (AM_C) 'of the copy panel (PA)' is set to the adjacent element of the free edge element (FBM_E) of the panel (PB), and the free edge element (FBM_E) of the panel (PB) is set to the copy panel. Set to the adjacent element of (PA) 'element (FAM_C)'. Then, as indicated by a circle symbol 1 in FIG. 19, the adjacent element number is updated and stored in the RAM 17. Here, step S56 constitutes the seventh step of the present invention.

  In step S57, the adjacent element (BM_F) in the free edge element (FBM_E) of the panel (PB) is detected, and in the subsequent step S58, the normal vector (BL_F) of the adjacent element (BM_F) passes through the copy panel (PA) ′. Element (AM_D) ′ is detected (see FIG. 18D). Note that the normal vector generated in step S58 is also a normal extending from an arbitrary part of the adjacent element (BM_F) by performing a predetermined calculation using the coordinate data of each node forming the adjacent element (BM_F). A vector may be generated.

  In step S59, among the adjacent elements in the element (AM_C) ′ of the copy panel (PA) ′, the adjacent element on the side without the adjacent element (AM_D) ′ detected in step S57, that is, the adjacent element (AM_B) ′ is illustrated. It deletes from shape data, as shown by 19 circular code | symbol 2 (refer FIG.18 (e)). In this way, the copy panel (PA) ′ is separated into the element (AM_C) ′ side and the element (AM_B) ′ side, thereby generating the analysis target member II as shown in FIG. 20B (step S60). ).

  In step S61, a copy element (AM_C) "is generated as a copy of the element (AM_C) 'in the copy panel (PA)', and is stored in the RAM 17. Thereby, the shape data is represented as indicated by a circle 3 in FIG. Updated.

  In step S62, the copy element (AM_C) "generated in step S61 is set as an adjacent element of the free edge element (FBM_E) 'of the copy panel (PB)' and the free edge element (FBM_E) of the panel (PB) '. Set 'to the adjacent element of the copy element (AM_C). As a result, the shape data is updated as indicated by a circle symbol 4 in FIG.

  In step S63, by designating the element (AM_B) ′ of the copy panel (PA) ′ as the adjacent element of the copy element (AM_C) ”, the shape data is updated as indicated by a circle symbol 5 in FIG. Thus, the element (AM_B) ′ side of the copy panel (PA) ′ separated in step S59 and the copy panel (PB) ′ are connected to generate the analysis target member III as shown in FIG. Step S64).

  In step S65, as shown in FIG. 19, the original data and the copy data are analyzed as members I to III, respectively, and the analysis result of this joint definition is stored in the HDD 13 and, for example, “input” is displayed via the display 12. "The joined members will be joined." Thereafter, in step S66, the joint definition analysis processing ends. In this manner, the joint between the first panel (PA) and the second panel (PB) is defined, and each panel (PA), (PB) can be associated on the data as a connection member.

  Next, based on FIG. 20, a method for determining whether or not an air pocket is generated that is executed on the analysis target members I to III according to the second embodiment will be described. Also in the second embodiment, the determination method according to the first embodiment (see FIG. 11) is executed. FIGS. 20A, 20B, and 20C are explanatory diagrams for explaining the processing contents of the air pocket determination program.

  The analysis target members I and III shown in FIGS. 20A and 20C are subjected to the same determination as the determination results of the analysis target members I to III in the first embodiment to form the analysis target members I and III. All the elements to be determined are liquid (paint). Therefore, a description will be given of the analysis target member II in which the attribute of all elements is determined to be air, that is, it is determined that an air pocket is generated.

  The control unit 18 executes the analysis process shown in the flowchart of FIG. 11 using the elements (AM_D) ′ and (BM_H) that are free edge elements forming the analysis target member II shown in FIG. 20B as initial boundary elements. . Then, the element attribute determination is executed as in the first embodiment, the element attribute from the element (BM_H) side is set to air one after another, and the element attribute from the element (AM_D) ′ side is set. Are set to air one after another. In this way, by executing the flowchart of FIG. 11 for the analysis target member II, it is determined that the attribute of all the elements is air. Therefore, the analysis target member II shown in FIG. Is determined to occur.

  The same effect as that of the first embodiment described above can be achieved also in the air pool generation simulation method in the workpiece to be immersed according to the second embodiment configured as described above.

  In addition, this invention is not limited to each embodiment mentioned above, A various change is possible in the range which does not deviate from the summary. For example, in each of the above-described embodiments, the floor panel member 40 including the first panel 40a and the second panel 40b that form the vehicle body 30 such as a passenger car as the object to be immersed has been shown. The invention is not limited to this, and for example, a body frame of a railway vehicle, a cabin of a construction machine, or the like may be an object to be treated.

It is a block diagram of the fluid analysis apparatus which performs the simulation method concerning the present invention. It is explanatory drawing explaining the coating line of a vehicle body. It is explanatory drawing explaining the numerical calculation model of the floor panel member in a vehicle body. It is a simple model figure which simplifies and shows the shape of each panel in a 1st embodiment. It is a schematic diagram which shows typically the element in the broken-line circle | round | yen B part of FIG. This is shape data before updating each element. It is the coordinate data of each node. It is a flowchart which shows the analysis process for defining the joining of each panel. (A), (b), (c) is explanatory drawing explaining the processing content of the flowchart of FIG. This is the updated data corresponding to FIG. It is a flowchart which shows the analysis process for determining generation | occurrence | production of an air pocket. (A), (b), (c) is explanatory drawing explaining the processing content of the flowchart of FIG. It is a simple model figure which simplifies and shows the shape of each panel in 2nd Embodiment. It is a schematic diagram which shows typically the element in the broken-line circle | round | yen C part of FIG. It is the shape data before the update of each element which concerns on 2nd Embodiment. It is the coordinate data of each node which concerns on 2nd Embodiment. It is a flowchart which shows the analysis process for defining the joining of each panel which concerns on 2nd Embodiment. (A)-(f) is explanatory drawing explaining the processing content of the flowchart of FIG. This is the updated data corresponding to FIG. (A), (b), (c) is explanatory drawing explaining the processing content of an air pocket determination program.

Explanation of symbols

10 Fluid analyzer (computer)
18 Control unit 30 Body body (substance to be treated)
34 Electrodeposition tank (paint tank)
35 Electrodeposition solution (paint)
40 Floor panel member (substance to be immersed)
40a First panel (one member)
40b Second panel (other members)
41 elements

Claims (6)

A method for simulating the occurrence of air stagnation in an object to be immersed in the object to be immersed, which is simulated by using a fluid analysis device .
By the control unit of the fluid analysis device,
A first step of dividing shape data of one member and the other member forming the object to be immersed into a plurality of two-dimensional elements;
A second step of calculating a centroid point of an element forming each member;
A third step of determining a distance between the center of gravity points of the elements of each member and determining whether or not the members are within a predetermined distance;
A fourth step of generating copy data of each member having the same information as each member after determining that the distance is within a predetermined distance in the third step;
A fifth step of generating normal vectors extending in opposite directions from the elements forming the original data and copy data of each member;
A sixth step of determining whether or not the normal vector penetrates each other between the elements of the members;
A seventh step of connecting the respective members by determining that the elements having normal vectors passing through are adjacent to each other after determining that they penetrate each other in the sixth step;
Among the elements forming the connection member connected in the seventh step, an element located at an end or a hole is set as an initial boundary element, and an element sharing a node with the initial boundary element is set as an adjacent element An eighth step to set,
A ninth step of analyzing whether the attribute of the adjacent element set in the eighth step is air or paint using the initial boundary element;
A tenth step of setting the adjacent element analyzed in the ninth step as a secondary boundary element and setting an element sharing a node with the secondary boundary element as an adjacent element;
An eleventh step of analyzing whether the attribute of the adjacent element set in the tenth step is air or paint using the secondary boundary element;
It is determined whether there is an adjacent element adjacent to the secondary boundary element, and if it is determined that there is an adjacent element adjacent to the secondary boundary element, there is no adjacent element adjacent to the secondary boundary element. A twelfth step that repeats the processing of each step in the order of the tenth step and the eleventh step and terminates the analysis when it is determined that there is no adjacent element adjacent to the secondary boundary element; An air accumulation generation simulation method for an object to be immersed, which is executed .   2. The method of simulating the occurrence of air accumulation in an object to be immersed according to claim 1, wherein in the ninth step and the eleventh step, the initial boundary element, the secondary boundary element, and the adjacent element are defined as respective elements. If the height of the center of gravity of the initial boundary element or the secondary boundary element is higher than the height of the center of gravity of the adjacent element, the attribute of the adjacent element is paint. And determining that the attribute of the adjacent element is air when the height of the centroid of the initial boundary element or the secondary boundary element is lower than the height of the centroid of the adjacent element. A method for simulating the occurrence of air stagnation in an immersion treatment.   3. The method for simulating the occurrence of air accumulation in the object to be immersed according to claim 1 or 2, wherein the object to be immersed is a vehicle body. A computer-executable program for executing an air pool generation simulation method in an object to be immersed for simulating an air pool generated in an object to be immersed at the time of immersion in a paint tank,
A first step of dividing shape data of one member and the other member forming the object to be immersed into a plurality of two-dimensional elements;
A second step of calculating a centroid point of an element forming each member;
A third step of determining a distance between the center of gravity points of the elements of each member and determining whether or not the members are within a predetermined distance;
A fourth step of generating copy data of each member having the same information as each member after determining that the distance is within a predetermined distance in the third step;
A fifth step of generating normal vectors extending in opposite directions from the elements forming the original data and copy data of each member;
A sixth step of determining whether or not the normal vector penetrates each other between the elements of the members;
A seventh step of connecting the respective members by determining that the elements having normal vectors passing through are adjacent to each other after determining that they penetrate each other in the sixth step;
Among the elements forming the connection member connected in the seventh step, an element located at an end or a hole is set as an initial boundary element, and an element sharing a node with the initial boundary element is set as an adjacent element An eighth step to set,
A ninth step of analyzing whether the attribute of the adjacent element set in the eighth step is air or paint using the initial boundary element;
A tenth step of setting the adjacent element analyzed in the ninth step as a secondary boundary element and setting an element sharing a node with the secondary boundary element as an adjacent element;
An eleventh step of analyzing whether the attribute of the adjacent element set in the tenth step is air or paint using the secondary boundary element;
It is determined whether there is an adjacent element adjacent to the secondary boundary element, and if it is determined that there is an adjacent element adjacent to the secondary boundary element, there is no adjacent element adjacent to the secondary boundary element. A twelfth step that repeats the processing of each step in the order of the tenth step and the eleventh step and terminates the analysis when it is determined that there is no adjacent element adjacent to the secondary boundary element; A computer-executable program for executing a method for simulating the occurrence of air stagnation in an object to be immersed, which is characterized by comprising:   The computer-executable program for executing the method of simulating the occurrence of air stagnation in a workpiece to be immersed according to claim 4, wherein the initial boundary element and the secondary boundary element are the ninth step and the eleventh step. , If the height of the center of gravity of the initial boundary element or the secondary boundary element is higher than the height of the center of gravity of the adjacent element The attribute of the adjacent element is determined to be paint, and when the height of the centroid of the initial boundary element or the secondary boundary element is lower than the height of the centroid of the adjacent element, the attribute of the adjacent element is air A computer-executable program for executing a simulation method for generating air stagnation in an object to be immersed.   The computer-executable program for executing the method for simulating the occurrence of air accumulation in an object to be immersed according to claim 4 or 5, wherein the object to be immersed is a body of a vehicle body. A computer-executable program for executing the pool generation simulation method.

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