JP2005346360A - Method for analyzing residual fluid, method for analyzing liquid pool, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently analyze residual fluid remaining in a target followed by dipping processing by simplifying analytical processing. <P>SOLUTION: A computer 10 generates an analytical model expressing a target by meshes. When the attribute of meshes corresponding to a space which may be a cause of residual fluid is set to a first material caused by the residual fluid in the analytical model, the attribute of meshes corresponding to a boundary with the external out of meshes corresponding to the space is set from the first material to a second material whose specific gravity is different from that of the first material. The meshes whose attribute is set to the first material are set as a target to be processed and the attribute is changed from the first material to the second material in accordance with the attribute of meshes existing around the target. Consequently the existence of a liquid pool is determined in accordance with the existence of meshes whose attribute is set to the first material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for analyzing a residual fluid remaining on an object in association with an immersion process.

  Electrodeposition coating is widely used as an undercoating for various members such as vehicle bodies and parts because a coating film uniformly adheres to the surface of an object and has excellent corrosion resistance. In this electrodeposition coating, an object is immersed in an electrodeposition bath filled with an electrodeposition solution, and a coating film is formed on the surface using the electrophoresis phenomenon or electrodialysis phenomenon of the polymer electrolyte. The This electrodeposition process including the dipping process ends when the object is pulled up from the electrodeposition tank.

In electrodeposition coating, from the viewpoint of uniform coating formation, it is important to perform the treatment in consideration of phenomena such as air accumulation and liquid accumulation caused by the immersion treatment. An air pool is a phenomenon in which air remains in a space such as a gap when an object is immersed in an electrodeposition tank, and a liquid pool is an electrodeposition liquid in the space after the object is lifted from the electrodeposition tank. It is a residual phenomenon. In the latter case, when a liquid pool occurs, the remaining electrodeposition liquid drips onto the surface of the coating film in a subsequent processing step (for example, a drying step), and a so-called “secondary sagging” is applied. Causes film formation. When a defective coating film is generated, the operator must scrape it off manually, leading to inconveniences such as an increase in manufacturing cost and a decrease in work efficiency. Therefore, conventionally, as disclosed in Patent Document 1, for example, the shape of the object is appropriately designed so as to suppress the occurrence of a liquid pool, and the immersion treatment is performed on the object.
Japanese Patent Laid-Open No. 06-88383

  By the way, the presence or absence of a liquid pool generated in an object can be determined in advance by a known analysis method using a free surface. However, in a case where the shape of the target object is complicated, such as a vehicle body, there is a problem that the analysis time becomes long because the analysis process is complicated.

  Therefore, an object of the present invention is to efficiently analyze the residual fluid remaining on the object in accordance with the immersion process by simplifying the analysis process.

  In order to solve this problem, the first invention provides an analysis method for analyzing a liquid pool generated in an object subjected to immersion treatment using a computer. This analysis method includes a first step of generating an analysis model representing an object with a mesh, and a second step of setting, in the analysis model, a mesh attribute corresponding to a space that may cause a liquid pool in the liquid. The third step of changing the attribute of the mesh corresponding to the boundary with the outside from the mesh corresponding to the space from the liquid to the gas, and the mesh having the mesh attribute set to the liquid as the processing target In the fourth step of changing the attribute from liquid to gas according to the mesh attribute existing in the model, and in the analysis model, the liquid pool generated in the object according to the presence or absence of the mesh with the mesh attribute set to liquid And a fifth step of determining whether or not there is.

  Here, in the first invention, in the analysis model, after the attribute of the mesh corresponding to the space is set to gas in the analysis model, the mesh is set to the boundary between the mesh and the wall surface of the target object. Preferably, the step is to set the attribute of the located mesh from gas to liquid.

  In the first invention, in the fourth step, if the attribute is gas and the mesh whose gravity center position is equal to or less than the gravity center position of the mesh to be processed is adjacent to the periphery, the attribute is liquid. Preferably, the step is to change from gas to gas.

  Furthermore, in the first invention, the meshes may be arranged in a lattice pattern. In this case, the fourth step is preferably a step of changing the attribute from liquid to gas when any attribute of the mesh adjacent to the left, right and bottom of the mesh to be processed is gas. .

  On the other hand, the second invention provides a computer program for causing a computer to execute the analysis method according to the first invention described above.

  Moreover, 3rd invention provides the analysis method which analyzes the residual fluid which remain | survives in a target object with a immersion process using a computer. In this analysis method, a first step of generating an analysis model representing an object with a mesh, and a first substance attributed to the residual fluid in the analysis model, the attribute of the mesh corresponding to a space that may cause the residual fluid is used. Among the meshes corresponding to the space, the attribute of the mesh corresponding to the boundary with the outside is set from the first material to the second material having a specific gravity different from that of the first physical property. In the third step, the mesh whose attribute is set to the first substance is processed, and the attribute is changed from the first substance to the second substance according to the mesh attribute existing around itself. And a fifth step of determining whether or not there is a liquid pool generated in the object in accordance with the presence or absence of the mesh whose mesh attribute is set to the first substance.

  According to the present invention, it is possible to determine the presence or absence of residual fluid remaining on the object by changing the attribute of the mesh based on the specific gravity relationship. According to such a method, since the object is analyzed after the object is expressed by a mesh, the processing can be simplified. In addition, since it is possible to uniquely determine whether to change the attributes of the processing target mesh according to the attributes of surrounding meshes, complex processing is not required, and analysis processing is speeded up and made efficient. Can be achieved.

  FIG. 1 is an overall configuration diagram of an analysis system according to the present embodiment. The analysis system 1 includes a computer 10, an input device 11 such as a keyboard and a mouse, a display device 12 such as a CRT and a liquid crystal display, and a storage device 13 such as a magnetic disk. The computer 10 is mainly composed of a CPU, a ROM, a RAM, and an input / output interface, and analyzes a liquid pool generated in an object subjected to immersion treatment.

  FIG. 2 is a block configuration diagram of the computer 10. The computer 10 has the process part 10a and the determination part 10b, when this is caught functionally. The processing unit 10a generates an analysis model in which the object is represented by a three-dimensional mesh or an analysis model in which a two-dimensional section of the object is represented by a mesh, depending on the purpose. In the present embodiment, for the sake of simplicity of explanation, description will be made using an analysis model in which a two-dimensional cross section of an object is expressed by a square mesh. In the analysis model, the processing unit 10a sets the mesh attribute corresponding to the space to liquid, and then changes the mesh attribute corresponding to the boundary with the outside from liquid to gas. Then, for a mesh whose attribute is set to liquid, the attribute is changed from liquid to gas according to the attribute of the mesh existing around itself. In the analysis model, the determination unit 10b determines whether or not there is a liquid pool generated in the object according to the presence or absence of a mesh whose attribute is set to liquid.

  Based on the information displayed on the display device 12, the operator operates the input device 11 to input the shape or numerical value of the object to be analyzed. The storage device 13 stores various databases necessary for analyzing the liquid pool. In the present embodiment, the attribute database 13a is important. The attribute database 13a is a database for storing attributes set in the mesh, and is composed of attribute record groups to which individual identification numbers (hereinafter referred to as “record numbers”) are attached for each object to be analyzed. Yes. In each attribute record, an identification number for identifying each mesh (hereinafter referred to as “mesh number”) and a mesh attribute are basically described in association with each other.

  3 and 4 are flowcharts showing an analysis procedure according to the present embodiment. First, in step 1, information related to the object is acquired in accordance with the operation of the input device 11 by the operator. Examples of information obtained in step 1 include the shape of the object and the analysis accuracy.

  In step 2, an analytical model is generated. The analysis model is a model for analysis in which a two-dimensional cross section of an object is expressed by a plurality of minute elements (mesh) each having the same shape. In the present embodiment, the two-dimensional cross section of the object including the vertical axis is modeled from the viewpoint of reproducing the fluid flow state in the direction of gravity. The individual meshes in the analysis model are set in a square shape because they can be easily expressed regardless of the shape of the object, and are arranged in a grid. The number of meshes per unit area of the analysis model can be arbitrarily set according to the analysis accuracy. For example, when the internal shape of the object is complicated, or when analyzing the liquid pool with high accuracy, the mesh is set densely. On the other hand, when the internal shape of the object is simple or when the determination of the liquid pool is performed with rough accuracy, the mesh is set to be sparser than the former. Each mesh is given a mesh number for identifying itself.

  In the mesh constituting the analysis model, there are a mesh corresponding to the member of the object and a mesh corresponding to the space. The space in the object is a structural gap, cavity, or depression (an area recessed inward from the outline defining the outer shape of the two-dimensional cross section of the object), etc., and can cause liquid pooling. . Therefore, in step 3, a mesh corresponding to space (hereinafter referred to as “space mesh”) is extracted from the analysis model. The attribute of the extracted space mesh is set to gas in order to indicate that its own mesh is space (air). Accordingly, a new attribute number is added to the attribute database 13a and a new attribute record is added. In this attribute record, the mesh number and attribute of the extracted spatial mesh are described in association with each other.

  In Step 4, a mesh located at the boundary with the wall surface of the target object, that is, a mesh adjacent to the mesh corresponding to the member of the target object is extracted from the extracted spatial mesh. The extracted spatial mesh is classified into a group to which an identifier “A” is assigned in order to distinguish it from other spatial meshes. The attributes of the space mesh classified into the group A are changed from gas to liquid (step 5). The change result is reflected in the attribute record added in the previous step 3 in the attribute database 13a. In this case, in the attribute record, the corresponding spatial mesh is searched using the mesh number as a search key (the same applies to the steps shown below).

  In step 6 following step 5, an outer boundary mesh is extracted from the spatial mesh classified into group A. This external boundary mesh is a mesh corresponding to the boundary with the outside of the object in the group A space mesh, that is, a mesh corresponding to an opening portion of the space. The attribute of the extracted external boundary mesh is changed from liquid to gas, and the description of the attribute database 13a is updated accordingly.

  In step 7, an identification number (hereinafter referred to as “group number”) n (n: natural number) for identifying itself is given to the space mesh of group A excluding the outer boundary mesh. In the processing after step 8 to be described later, because the spatial mesh to be processed is selected according to the group number n, the group number n is assigned in association with the mesh selection order. Specifically, the group number n is assigned so that the processing proceeds sequentially from the upper space mesh to the lower space mesh of the analysis model. In this case, the group numbers n are assigned to the air meshes that coincide in height so that the process proceeds from the spatial mesh close to the external boundary mesh to the distant spatial mesh.

  FIG. 5 is an explanatory diagram of the group number n. FIGS. 4A and 4B show analysis models relating to objects having different shapes, and for convenience of explanation, a boundary with a member and a spatial mesh are shown. The space mesh classified into the group A excluding the external boundary mesh is hatched and has a group number n for identifying itself. Along with the assignment of the group number, the corresponding attribute record in the attribute database 13a describes the group number n in association with the spatial mesh.

  In step 8, according to the loop variable i, a spatial mesh having a group number corresponding to the number “i” is selected as a processing target mesh. The loop variable i is reset to an initial value (“1” in the present embodiment) in an initial routine that is performed prior to the start of this routine. Therefore, initially, the spatial mesh having the group number corresponding to the number “1” is selected as the processing target mesh.

  In step 9, it is determined whether or not the processing target mesh has an attribute change condition based on the attributes of the spatial mesh existing around. Specifically, in the attribute record, spatial meshes adjacent to the side and lower side of the processing target mesh, that is, right and left and lower are searched using the mesh number as a search key. If any attribute of the extracted spatial mesh is gas, it is determined that the attribute change condition is satisfied. On the other hand, when all the attributes of each spatial mesh are fluid, it is determined that the attribute change condition is not provided. If an affirmative determination is made in step 9, that is, if the attribute change condition is satisfied, the process proceeds to step 10. On the other hand, if a negative determination is made in step 9, that is, if the attribute change condition is not satisfied, step 10 is skipped and the process proceeds to step 11.

  In step 10, the attribute of the processing target mesh (group number i) is changed from liquid to gas. Accordingly, the attribute of the processing target mesh is changed from liquid to gas in the attribute database 13a.

  In step 11, it is determined whether or not the loop variable i has reached the maximum value nmax of the group number n. If a negative determination is made in step 11, that is, if the loop variable i has not reached the maximum value nmax of the group number n, the process proceeds to step 12. In step 12, the loop variable i is incremented by 1, and the process returns to step 8. By the determination process of step 11, the process from step 8 to step 10 is repeatedly executed while sequentially shifting the process target mesh until the loop variable i reaches the maximum value nmax of the group number n. On the other hand, if the determination in step 11 is affirmative, that is, if the loop variable i has reached the maximum group number nmax, the process proceeds to step 13.

  In step 13, it is determined whether or not there is a spatial mesh whose attribute is liquid in the analysis model. Specifically, an attribute record is searched based on the record number in the attribute database 13a. And the presence or absence is judged based on the attribute of each spatial mesh described in the extracted attribute record. If an affirmative determination is made in step 13, that is, if there is a spatial mesh belonging to the liquid, the process proceeds to step 14. Then, in step 14, after performing a liquid pool determination process such as displaying a message indicating that a liquid pool has occurred on the display device 12, the routine exits. In this case, the computer 10 may perform processing such as displaying the analysis model in color according to the attribute of the spatial mesh so that the position of the spatial mesh belonging to the liquid can be known. On the other hand, if a negative determination is made in step 13, that is, if the attribute of all the spatial meshes is gas, step 14 is skipped and the routine is exited. In this case, processing such as displaying a message indicating that no liquid pool occurs may be performed.

  Hereinafter, the concept of the analysis method of the present embodiment will be described. In this analysis method, the individual spatial meshes that make up the analysis model are set by setting attributes with different physical properties (specifically, specific gravity), such as a liquid that simulates an electrodeposition liquid or a gas that simulates air. It will be effective for the first time. The attribute set for each spatial mesh expresses the presence of an object corresponding to the attribute at its own mesh position.

  The two-dimensional cross section of the object corresponding to the analysis model includes a member of the object or a region corresponding to a space. Of these regions, the region corresponding to the space may become a residual space for the electrodeposition liquid when the object is pulled up from the electrodeposition tank (occurrence of a liquid pool). Therefore, the attribute of the spatial mesh in the analysis model is set to gas from the viewpoint of searching for a space that causes a liquid pool (step 3).

  Further, the electrodeposition liquid having a specific gravity heavier than that of air does not float in the air, and if the electrodeposition liquid remains as a liquid pool, it exists at least on the wall surface of the object. . Therefore, from the viewpoint of expressing the electrodeposition liquid that may remain in the analysis model, the attribute of the spatial mesh belonging to group A is changed from gas to liquid. On the other hand, when the space is open to the outside, it is considered that the electrodeposition liquid flows out from the position. In this case, since the electrodeposition liquid does not stay at that position, the opening becomes a space. Therefore, in the spatial mesh classified into group A, the attribute of the external boundary mesh is changed from liquid to gas (step 6).

  As described above, when the initial condition regarding the attribute of each spatial mesh is set, the flow state of the electrodeposition liquid when it is pulled up from the electrodeposition tank is reproduced by changing the attribute of the mesh based on the specific gravity relationship. . That is, when there is a mesh belonging to a gas immediately below the mesh to be processed, the attribute of the mesh is changed to gas from the knowledge that a liquid having a high specific gravity flows downward. In addition, when there is a mesh belonging to the gas on the left and right of the processing target mesh, substances with different specific gravity do not stay at the same height, and from the knowledge that liquid with heavy specific gravity flows downward, The attribute of the mesh is changed to gas. Therefore, in this embodiment, when the attribute of the spatial mesh adjacent to the left, right, and bottom is gas, it is determined that the attribute change condition is satisfied, and the attribute of the processing target mesh is changed from liquid to gas. (Steps 9 and 10).

  By changing the attribute of the mesh based on such a specific gravity relationship, it is possible to determine the presence or absence of a liquid pool according to the presence or absence of a spatial mesh belonging to the liquid. According to such a method, the object is represented by a mesh, and the liquid pool is analyzed from its attributes, so that the processing can be simplified compared to the analysis method using a free surface. In addition, since it is possible to determine whether or not to change the attribute of the mesh to be processed according to the attributes of the surrounding mesh, no complicated analysis process is required, and the analysis process can be made faster and more efficient. Can be planned.

  According to the present invention, the setting of the initial condition is not limited to the above-described embodiment, and the initial condition may be set according to the following procedure. First, as a first step, the attribute of the spatial mesh is set to liquid. As a second step, the outer boundary mesh is extracted and the attribute of the outer boundary mesh is changed from liquid to gas. In this initial condition setting method, when the liquid accumulation occurs by repeatedly performing the attribute changing process shown in Step 8 to Step 12 to some extent, not only the presence / absence but also the layout of the attribute of the spatial mesh The state of the pool can also be reproduced. However, in the above-described embodiment, it is not necessary to execute the attribute changing process over the entire space mesh, which is advantageous in terms of improving the efficiency of the analysis.

  In this embodiment, the analysis model is generated using a square mesh. However, the present invention is not limited to this, and a polygonal mesh such as a triangle or a pentagon may be used. However, in this case, the position of the center of gravity is further considered together with the attributes of the spatial mesh existing on the left, right, and bottom, and the attribute of the mesh is changed from liquid to gas. Specifically, in the case where the attribute is space and there is a space mesh in the surroundings where the center of gravity is equal to or less than the center of gravity, the attribute of the mesh to be processed is changed from liquid to gas. Become.

  In this embodiment, the analysis model is generated using a two-dimensional mesh, but the analysis model of the present invention may be generated using a three-dimensional mesh. 3D mesh is a concept that includes at least a 2D mesh. Even when an analysis model is generated using a 3D mesh, an analysis model is generated using a 2D cross-section mesh without being constrained by the shape of the mesh. It is possible to process in the same manner as in the case of.

  Further, the present invention is not limited only to the analysis of the liquid pool from the viewpoint of the analysis method based on the specific gravity relationship. In addition to this, the present invention can be applied to analysis of residual fluid generated in an object due to immersion treatment, for example, air pool. In the analysis of the air pool, it is necessary to reproduce the flow state of the air in the electrodeposition tank. Therefore, the presence or absence can be analyzed by reversing the relationship between the gas and the liquid in the method of the present embodiment. However, unlike the above-described embodiment, in the case where the attribute is liquid and there is a spatial mesh in the periphery whose center of gravity is equal to or greater than its own center of gravity, the attribute of the processing target mesh whose attribute is space is It should be noted that the change from gas to liquid is required.

  In addition, a program that can be executed by a computer that executes the analysis method of the above-described embodiment also functions as part of the present invention. Of course, a recording medium on which the computer program is recorded may be supplied to a system having the configuration as shown in FIG. In this case, the computer 10 in this system can achieve the object of the present invention by reading and executing the computer program stored in the recording medium. Since the computer program itself realizes the novel functions of the present invention, a recording medium on which the program is recorded also constitutes the present invention. Examples of the recording medium on which the computer program is recorded include a CD-ROM, a flexible disk, a hard disk, a memory card, an optical disk, a DVD-ROM, and a DVD-RAM.

Overall configuration diagram of analysis system according to this embodiment Block diagram showing functional configuration of computer A flowchart showing an analysis procedure according to the present embodiment A flowchart showing an analysis procedure according to the present embodiment Illustration of group number

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Computer 10a Processing part 10b Judgment part 11 Input device 12 Display apparatus 13 Storage apparatus 13a Attribute database

Claims (7)

In a method for analyzing a liquid pool generated in an object subjected to immersion treatment,
A first step of generating an analysis model representing the object with a mesh;
A second step of setting the attribute of the mesh corresponding to a space that can cause the liquid pool in the analysis model to be a liquid;
A third step of changing an attribute of the mesh corresponding to a boundary with the outside of the mesh corresponding to the space from the liquid to a gas;
A fourth step of changing the attribute from the liquid to the gas in accordance with the attribute of the mesh existing around itself, with the mesh having the mesh attribute set to the liquid as a processing target;
And a fifth step of determining whether or not the liquid pool is present according to the presence or absence of the mesh set in the liquid in the analysis model.   In the analysis model, after setting the mesh attribute corresponding to the space to the gas in the analysis model, the second step is positioned at a boundary with the wall surface of the target object among the meshes set to the gas. The method for analyzing a liquid pool according to claim 1, further comprising: setting an attribute of the mesh to be changed from the gas to the liquid.   In the fourth step, when the attribute is gas, and the mesh whose gravity center position is equal to or smaller than the gravity center position of the mesh to be processed is adjacent to the periphery, the attribute is extracted from the liquid. 3. The method for analyzing a liquid pool according to claim 1, wherein the method is a step of changing to gas. The meshes are arranged in a lattice pattern,
The fourth step is a step of changing the attribute from the liquid to the gas when any attribute of the mesh adjacent to the side and below the mesh to be processed is the gas. The method for analyzing a liquid pool according to claim 3. In a computer program for causing a computer to execute a method for analyzing a liquid pool generated in an object subjected to immersion treatment,
A first step of generating an analysis model representing the object with a mesh;
A second step of setting the attribute of the mesh corresponding to a space that can cause the liquid pool in the analysis model to be a liquid;
A third step of changing an attribute of the mesh corresponding to a boundary with the outside of the mesh corresponding to the space from the liquid to a gas;
A fourth step of changing the attribute from the liquid to the gas in accordance with the attribute of the mesh existing around itself, with the mesh having the mesh attribute set to the liquid as a processing target;
And a fifth step of determining whether or not the liquid pool is present in accordance with the presence or absence of the mesh whose attribute is set to the liquid in the analysis model. A computer program that causes a computer to execute. In the analysis model, after setting the mesh attribute corresponding to the space to the gas in the analysis model, the second step is positioned at a boundary with the wall surface of the target object among the meshes set to the gas. The computer program according to claim 5, wherein the step of setting the attribute of the mesh to be set from the gas to the liquid. In the method of analyzing the residual fluid remaining on the object due to the immersion treatment,
A first step of generating an analysis model representing the object with a mesh;
A second step of setting, in the analytical model, an attribute of the mesh corresponding to a space that can cause the residual fluid to a first substance caused by the residual fluid;
A third step of setting an attribute of the mesh corresponding to the boundary with the outside of the mesh corresponding to the space from the first substance to a second substance having a specific gravity different from that of the first physical property. When,
Change the attribute from the first substance to the second substance according to the attribute of the mesh existing around the mesh with the mesh attribute set to the first substance as a processing target A fourth step to:
And a fifth step of determining the presence or absence of the liquid pool generated in the object in accordance with the presence or absence of the mesh whose attribute is set to the first substance. analysis method.

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