JP2005344158A - Process for analyzing air entrapment, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently analyze a residual fluid remaining in an object when being immersed and treated, by simplifying an analysis process. <P>SOLUTION: This analysis process comprises the steps of: making a computer 10 output an analytical model which exhibits the object with the use of a mesh; in the analytical model, setting the attribute of the mesh corresponding to the space that can trap air therein, to gas; changing the attribute of the mesh corresponding to a boundary with the outside, among the meshes corresponding to the space, to liquid from the gas; changing the attribute of the mesh in the object, of which the attribute has been set to the gas, to the liquid from the gas, in accordance with the attribute of the mesh existing around itself; and judging the presence or absence of air entrapment, in accordance with the presence or absence of the mesh of which the attribute is set to the gas after the above steps. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for analyzing an air pocket generated in an object when performing immersion treatment.

  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

In electrodeposition coating, it is important to take into account an air pocket generated in an object when performing immersion treatment from the viewpoint of uniform coating formation. Air accumulation is a phenomenon in which air remains in a space such as a gap when an object is immersed in an electrodeposition bath. When air accumulation occurs, a region where the electrodeposition liquid does not adhere to the object is generated, which may cause an unpainted region or uneven coating. Therefore, conventionally, as disclosed in Patent Document 1, for example, the immersion treatment is performed after the shape of the object is appropriately designed so as not to cause air accumulation.
JP-A-10-45037

  By the way, the presence or absence of the air pocket generated in the object can be determined in advance by a well-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.

  Accordingly, an object of the present invention is to efficiently analyze an air pocket generated in an object when performing an immersion process by simplifying the analysis process.

  In order to solve such a problem, the first invention provides a method for analyzing an air pocket generated in an object when an immersion process is performed. In this air pool analysis method, a first step of generating an analysis model representing an object with a mesh, and a second attribute of setting an attribute of the mesh corresponding to a space that may cause air pool in the analysis model to gas. And the third step of changing the attribute of the mesh corresponding to the boundary with the outside of the mesh corresponding to the space from the gas to the liquid, and the mesh in which the attribute of the mesh is set to gas, In the fourth step of changing the attribute from gas to liquid according to the mesh attribute existing around the self, and in the analysis model, depending on the presence or absence of the mesh with the mesh attribute set to gas, And a fifth step of determining the presence or absence.

  Here, in the first invention, in the second step, in the analysis model, after setting the attribute of the mesh corresponding to the space to the liquid, among the meshes set to the liquid, at the boundary with the wall surface of the object. Preferably, this is a step of setting the attribute of the located mesh from liquid to gas.

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

  Furthermore, in the first invention, the meshes are arranged in a grid pattern, and the fourth step is when the attribute of any of the meshes adjacent to the left, right, and top of the mesh to be processed is liquid In addition, it is preferable to change the attribute from gas to liquid.

  The second invention provides a computer program for causing a computer to execute the analysis method according to the first invention described above.

  According to the present invention, different physical properties of gas or liquid are set as mesh attributes. And the mesh whose attribute is set to gas is changed from gas to liquid according to the attribute of the mesh existing around the mesh. Thereby, according to the presence or absence of the mesh whose attribute is set to gas, it is possible to determine the presence or absence of air pockets generated in the object when the immersion treatment is performed. According to such a method, since the object is analyzed after the object is expressed by a mesh, the processing can be simplified. Moreover, since it is determined according to the attribute of the surrounding mesh whether the attribute of a process target mesh is changed, a complicated process is not required and the analysis process can be speeded up and made efficient.

  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 an air pocket generated in an object when the immersion process is performed.

  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 attribute of the mesh corresponding to the space to gas, and changes the attribute of the mesh corresponding to the boundary with the outside from gas to liquid. Then, for a mesh whose attribute is set to gas, the attribute is changed from gas to liquid according to the attribute of the mesh existing around itself. In the analysis model, the determination unit 10b determines whether there is an air pocket generated in the object according to whether there is a mesh whose attribute is set to gas.

  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 air pockets. In this 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 the analysis of the air pool is performed 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 air accumulation 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.

  The mesh constituting the analysis model includes a mesh corresponding to the member of the object and a mesh corresponding to the space of the object. The space of the object is a structural gap, cavity, or depression (area recessed inward from the outline defining the outline of the two-dimensional cross section of the object), etc., and the air when performing the immersion treatment This can cause accumulation. In step 3, a mesh corresponding to a space (hereinafter referred to as “space mesh”) is extracted from the analysis model, and its attribute is set to liquid. 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 attribute of the spatial mesh classified into the group A is changed from liquid to gas (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 gas to liquid, 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 lower space mesh to the upper space mesh of the analysis model. In this case, group numbers n are assigned so that the air meshes that coincide in height are processed from a spatial mesh close to the outer boundary mesh to a spatial mesh far away.

  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 n, the group number n is described in association with the spatial mesh in the corresponding attribute record in the attribute database 13a.

  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, the left, right, and upper sides are searched using the mesh number as a search key. If any attribute of the extracted spatial mesh is liquid, 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 gas to liquid. Accordingly, the attribute of the processing target mesh is changed from gas to liquid 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 space mesh whose attribute is gas 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 gas, the process proceeds to step 14. Then, in step 14, the routine exits this routine after performing an air retention determination process such as displaying a message indicating that air retention has occurred on the display device 12. 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 gas can be known. On the other hand, if a negative determination is made in step 13, that is, if the attributes of all the spatial meshes are liquid, step 14 is skipped and the routine is exited. In this case, a process such as displaying a message indicating that no air accumulation 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 the 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 of air when the object is immersed in the electrodeposition tank (occurrence of air accumulation). Therefore, first, by extracting the space mesh and setting the attribute of the space mesh to liquid (step 3), the initial state in which the object is immersed in the electrodeposition tank is reproduced.

  By the way, when air remains in the space of the object, air having a lighter specific gravity than the electrodeposition liquid exists at least on the wall surface of the object. Therefore, from the viewpoint of expressing the air that may remain in the analysis model, the attribute of the spatial mesh belonging to group A is changed from liquid to gas (step 5). On the other hand, when the space is open to the outside, air is discharged from the position to the outside, and the opening is filled with the electrodeposition liquid. Therefore, in the spatial mesh classified into the group A, the attribute of the external boundary mesh is changed from gas to liquid (step 6).

  As described above, when the initial conditions regarding the attributes of each spatial mesh are set, the flow state of the electrodeposition liquid and air when immersed in the electrodeposition tank is reproduced by changing the attribute of the mesh based on the specific gravity relationship. The In other words, if there is a mesh that belongs to the liquid immediately above the mesh to be processed, the knowledge that the liquid with a heavy specific gravity moves downward (air moves upward), the attribute of the mesh is changed from the gas. Changed to liquid. In addition, when there are meshes belonging to the liquid on the left and right of the processing target mesh, substances having different specific gravity do not stay at the same height, and from the viewpoint that gas with a low specific gravity flows upward, The mesh attribute is changed from gas to liquid. Therefore, in this embodiment, when the attribute of the spatial mesh adjacent to the left and right and above is liquid, it is determined that the attribute change condition is satisfied, and the attribute of the processing target mesh is changed from gas to liquid ( 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 an air reservoir according to the presence or absence of a spatial mesh belonging to the gas. According to such a method, the object is represented by a mesh and the analysis of the air pool is performed from the attribute, so that the processing can be simplified as compared with 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, complicated analysis processing is not required, and the analysis processing is speeded up and made efficient. be able to.

  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 gas. As a second step, the outer boundary mesh is extracted and the attribute of the outer boundary mesh is changed from gas to liquid. In this initial condition setting method, if the air retention 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 attributes of the space 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 in addition to the attributes of the spatial mesh existing on the left, right, and bottom, and the attribute of the mesh is changed from gas to liquid. Specifically, in the case where the attribute is space and there is a space mesh in the surroundings where the position of the center of gravity is equal to or less than the position of the center of gravity, the attribute of the processing target mesh is changed from gas to liquid. 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.

  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 (6)

In the analysis method of the air pocket generated in the object when the immersion treatment is performed,
A first step of generating an analysis model representing the object with a mesh;
A second step of setting, in the analysis model, an attribute of the mesh corresponding to a space that can cause the air accumulation;
A third step of changing the attribute of the mesh corresponding to the boundary with the outside of the mesh corresponding to the space from the gas to the liquid;
A step of changing the attribute of the mesh from the gas to the liquid according to the attribute of the mesh existing around the mesh with the mesh having the mesh attribute set as the processing target;
A method for analyzing an air reservoir, characterized in that, in the analysis model, a fifth step of determining the presence or absence of the air reservoir according to the presence or absence of the mesh whose attribute is set to the gas.   In the analysis model, after the mesh attribute corresponding to the space is set to the liquid in the analysis model, the second step is positioned at a boundary with the wall surface of the object among the meshes set to the liquid. 2. The method for analyzing an air reservoir according to claim 1, wherein the step of setting an attribute of the mesh to be performed from the liquid to the gas.   In the fourth step, when the attribute is liquid and the mesh whose gravity center position is equal to or greater than the gravity center position of the mesh to be processed is adjacent to the periphery, the attribute is extracted from the gas. 3. The method for analyzing an air reservoir according to claim 1, wherein the method is a step of changing to a liquid. The meshes are arranged in a lattice pattern,
The fourth step is a step of changing the attribute from the gas to the liquid when any attribute of the mesh adjacent to the side and above the mesh to be processed is the liquid. The method for analyzing an air reservoir according to claim 3. In a computer program for causing a computer to execute a method for analyzing an air pocket generated in an object during immersion treatment,
A first step of generating an analysis model representing the object with a mesh;
A second step of setting, in the analysis model, an attribute of the mesh corresponding to a space that can cause the air accumulation;
A third step of changing the attribute of the mesh corresponding to the boundary with the outside of the mesh corresponding to the space from the gas to the liquid;
A step of changing the attribute of the mesh from the gas to the liquid according to the attribute of the mesh existing around the mesh with the mesh having the mesh attribute set as the processing target;
And a fifth step of determining whether or not the air pool is present according to the presence or absence of the mesh whose attribute is set to the gas in the analysis model. A computer program that causes a computer to execute. In the analysis model, after the mesh attribute corresponding to the space is set to the liquid in the analysis model, the second step is positioned at a boundary with the wall surface of the object among the meshes set to the liquid. The computer program according to claim 5, wherein the attribute of the mesh is set from the liquid to the gas.

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