JP2012208540A - Simulation method and simulation program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve prediction precision of air stagnation while suppressing working costs.SOLUTION: From among a plurality of nodal points constituting a car body analysis model, a nodal point i10 positioning in a terminal is set as a boundary nodal point in contact with an electrodeposition liquid. When determining whether or not an adjacent nodal point i9 adjacent to the boundary nodal point is in contact with the electrodeposition liquid, an air bubble model deposited on a work surface between the nodal points i9 and i10 is set, and a buoyancy component force Fup which becomes parallel with the work surface is calculated from a buoyancy Fu operating on the air bubble model. Continuously, a thrust component force Flp which becomes parallel with the work surface is calculated from a flow thrust Fl of the electrodeposition liquid operating on the air bubble model. Then, a resultant force (Fup+Flp) operating on the air bubble model is calculated from the buoyancy component force Fup and the thrust component force Flp, and it is determined whether or not the resultant force exceeds an adhesive force Fs of the air bubble model deposited on the work surface. In the case where the resultant force exceeds the adhesive force, the air bubble model moves, thereby determining that the adjacent nodal point i9 is in contact with the electrodeposition liquid.

Description

  The present invention relates to a simulation technique for predicting air accumulation when a work is submerged in a processing tank.

  As a method of painting or plating a workpiece, there is a dip method in which the workpiece is submerged in a treatment tank in which a treatment liquid is stored. In such a dip method, in order to satisfactorily form a paint film or a metal film, a work shape that does not cause air accumulation is required. Therefore, in order to efficiently design a workpiece shape that does not cause air accumulation, a simulation method for predicting air accumulation at the design stage has been proposed (for example, see Patent Document 1).

JP 2007-39802 A

  In the simulation method of Patent Document 1, the flow state of the processing liquid in the processing tank and the occurrence state of the air pool are made into a database, and the occurrence state of the air pool is predicted with reference to this database. In this way, it is possible to predict the air pool with high accuracy because it considers the flow status of the processing liquid, but the flow status of the processing liquid and the occurrence status of the air pool according to the individual workpiece shape And making it a database has been a factor of increasing work costs.

  An object of the present invention is to improve the accuracy of predicting air pockets while suppressing work costs.

  The simulation method of the present invention is a simulation method for predicting air accumulation when a workpiece is submerged in a processing liquid, and an element located at an end is brought into contact with the processing liquid from a plurality of elements constituting the analysis model of the workpiece. A boundary setting step set as a boundary element and an adjacent element adjacent to the boundary element are extracted from a plurality of elements constituting the analysis model of the workpiece, and whether the adjacent element is in contact with the processing liquid or air is determined. A gas-liquid determining step, wherein the gas-liquid determining step sets a bubble model that adheres to the work surface between the boundary element and the adjacent element with a predetermined adhesion force; and Based on the buoyancy acting on the bubble model, a buoyancy component calculation step for calculating a buoyancy component force in a direction parallel to the workpiece surface; and acting on the bubble model A thrust component calculating step for calculating a thrust component in a direction parallel to the workpiece surface based on the flow thrust of the processing liquid, and adding the buoyancy component and the thrust component to the bubble model. On the other hand, a resultant force calculating step for calculating a resultant force acting in a direction parallel to the work surface, and when the resultant force exceeds the adhesion force, it is determined that the adjacent element is in contact with the processing liquid, while the resultant force is A determination step of determining that the adjacent element is in contact with air when the adhesion force is less than the predetermined value.

  The simulation method of the present invention has a boundary update step of setting the adjacent element as a new boundary element when it is determined that the adjacent element is in contact with the processing liquid, and the gas-liquid determination step is newly set. An adjacent element adjacent to the boundary element is extracted, and it is determined whether the adjacent element is in contact with the processing liquid or air.

  The simulation method of the present invention is characterized in that the flow thrust of the treatment liquid acting on the bubble model is obtained by referring to a database storing the flow direction and flow velocity of the treatment liquid for each coordinate of the analysis model. .

  The simulation method of the present invention is characterized in that the elements constituting the analysis model are a plurality of surface elements that divide the surface shape of the workpiece, or a plurality of node elements provided at vertices of the surface elements.

  The simulation program of the present invention is a simulation program for predicting air accumulation when a work is submerged in a processing liquid, and contacts a processing liquid with an element located at an end from a plurality of elements constituting the analysis model of the work. A boundary setting step set as a boundary element and an adjacent element adjacent to the boundary element are extracted from a plurality of elements constituting the analysis model of the workpiece, and whether the adjacent element is in contact with the processing liquid or air is determined. A gas-liquid determining step, wherein the gas-liquid determining step sets a bubble model that adheres to the work surface between the boundary element and the adjacent element with a predetermined adhesion force; and A buoyancy component force calculating step for calculating a buoyancy component force in a direction parallel to the workpiece surface based on a buoyancy force acting on the bubble model; Based on the flow thrust of the treatment liquid acting on the Dell, a thrust component calculating step for calculating a thrust component in a direction parallel to the work surface, and adding the buoyancy component and the thrust component, A resultant force calculating step for calculating a resultant force acting in a direction parallel to the workpiece surface with respect to the bubble model; and when the resultant force exceeds the adhesion force, the adjacent element is determined to be in contact with the processing liquid, A determination step of determining that the adjacent element is in contact with air when the resultant force is less than the adhesion force.

  The simulation program of the present invention has a boundary update step of setting the adjacent element as a new boundary element when it is determined that the adjacent element is in contact with the processing liquid, and the gas-liquid determination step is newly set. An adjacent element adjacent to the boundary element is extracted, and it is determined whether the adjacent element is in contact with the processing liquid or air.

  In the simulation program of the present invention, the flow thrust of the processing liquid acting on the bubble model is obtained with reference to a database storing the flow direction and flow velocity of the processing liquid for each coordinate of the analysis model. .

  In the simulation program of the present invention, the elements constituting the analysis model are a plurality of surface elements that divide the surface shape of the workpiece, or a plurality of node elements provided at the vertices of the surface elements.

  According to the present invention, a bubble model that adheres to a workpiece surface with a predetermined adhesion force is set, a buoyancy component force that is parallel to the workpiece surface is calculated from a buoyancy that acts on the bubble model, and a treatment liquid that acts on the bubble model is calculated. A thrust component force parallel to the work surface is calculated from the flow thrust force. Then, the resultant force acting on the bubble model is calculated based on the buoyancy component force and the thrust component force, and the gas-liquid determination is performed by comparing the resultant force and the adhesion force. Thereby, the flow thrust of the treatment liquid can be taken into consideration, and the prediction accuracy of the air pool can be improved. In addition, since the influence on the air pool due to the flow thrust of the processing liquid is calculated using the bubble model, it is not necessary to prepare a large-scale database, and the operation cost can be greatly reduced.

It is the schematic which shows an electrodeposition coating process. It is a block diagram which shows a simulation apparatus. It is the schematic which shows a vehicle body analysis model. It is explanatory drawing which shows the data of the vehicle body analysis model stored in a memory | storage device. (a) And (b) is explanatory drawing which shows the procedure at the time of carrying out gas-liquid determination of the vehicle body analysis model. (a) is explanatory drawing which shows a vehicle body analysis model along the AA line of Fig.5 (a), (b) is description which shows a vehicle body analysis model along the AA line of FIG.5 (b). FIG. (a)-(c) is explanatory drawing which shows the procedure at the time of performing a gas-liquid determination about an adjacent node. It is the schematic which shows an example of the database referred when calculating a flow thrust. (a)-(c) is explanatory drawing which shows the procedure at the time of performing a gas-liquid determination about an adjacent node. (a) is explanatory drawing which shows the gas-liquid determination result of the vehicle body analysis model by the conventional simulation method and simulation program which do not consider the flow thrust. Moreover, (b) is an explanatory view showing the gas-liquid determination result of the vehicle body analysis model by the simulation method and simulation program of the present invention considering the flow thrust. (a) is explanatory drawing which shows a vehicle body analysis model along the AA line of Fig.10 (a), (b) is description which shows a vehicle body analysis model along the AA line of FIG.10 (b). FIG. It is a flowchart which shows the prediction procedure of an air pocket. It is a flowchart which shows the procedure of the gas-liquid determination in step S7 in detail.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing an electrodeposition coating process. As shown in FIG. 1, in order to perform electrodeposition coating on a vehicle body 10 that is a workpiece, a treatment tank 11 in which an electrodeposition liquid (treatment liquid) is stored is installed in the electrodeposition coating process. After pretreatment such as degreasing and surface adjustment for the vehicle body 10, the vehicle body 10 is submerged in the treatment tank 11 and energized to form an electrodeposition coating on the outer surface and the inner surface of the vehicle body 10. Will be. In order to obtain good coating quality in this electrodeposition coating process, a vehicle body shape that does not generate an air pocket when the vehicle body 10 is submerged in the treatment tank 11 is required. In order to efficiently design such a vehicle body shape, it is important to predict the occurrence of air pockets at the design stage. In addition, a plurality of nozzles (not shown) are installed in the processing tank 11 and the electrodeposition liquid is discharged from these nozzles. For this reason, it is necessary to consider the flow of the electrodeposition liquid in the processing tank 11 in order to predict the occurrence of air pools with high accuracy.

  Hereinafter, a simulation method and a simulation program according to an embodiment of the present invention will be described. Here, FIG. 2 is a block diagram showing the simulation device 12, and a simulation method and a simulation program are executed by the simulation device 12. As shown in FIG. 2, the simulation apparatus 12 includes a calculation device 13 configured by a CPU, a memory, and the like, an input device 14 such as a keyboard, a display device 15 such as a liquid crystal display, and a storage device 16 such as a magnetic disk. . The simulation apparatus 12 may be configured using a single computer such as a microcomputer or a personal computer, or may be configured using a plurality of computers connected to each other via a network.

  The storage device 16 of the simulation device 12 stores a vehicle body analysis model (analysis model) representing the entire vehicle body. Here, FIG. 3 is a schematic diagram showing the vehicle body analysis model, and FIG. 4 is an explanatory diagram showing data of the vehicle body analysis model stored in the storage device 16. As shown in the enlarged portion of FIG. 3, the vehicle body analysis model is composed of a plurality of surface elements (elements) that divide the surface shape of the vehicle body 10 and node elements (elements) provided at the vertices of the surface elements. . The vehicle body analysis model is stored in the storage device 16 in the form of coordinate data where each node element (hereinafter referred to as a node) is located. As shown in FIG. 4, the storage device 16 stores the number data of the panel members constituting the vehicle body analysis model, the number data of the nodes included in each panel member, the coordinate data of each node (X coordinate value, Y coordinate value, Z Coordinate values) etc. are stored. Note that the direction of the Z axis in the XYZ orthogonal coordinate system is set to be opposite to the gravity direction G. As the vehicle body analysis model, a vehicle body analysis model used for collision deformation simulation or the like can be used.

  Further, the arithmetic device 13 is provided with a gas-liquid determination unit 17, and the gas-liquid determination unit 17 executes a gas-liquid determination process for each node of the vehicle body analysis model. The gas-liquid determination process is a process for determining whether each node constituting the vehicle body analysis model is a node in contact with the electrodeposition liquid (liquid) or a node in contact with air (gas). That is, the gas-liquid determination process is a process for determining whether the attribute data of each node is an electrodeposition liquid or air. Here, FIGS. 5 (a) and 5 (b) are explanatory views showing a procedure when the vehicle body analysis model I is determined to be gas-liquid. For ease of explanation, FIG. 5 shows a simplified vehicle body analysis model I. 6A is an explanatory view showing the vehicle body analysis model I along the line AA in FIG. 5A, and FIG. 6B is along the line AA in FIG. 5B. FIG.

  As shown in FIGS. 5A and 6A, first, in the gas-liquid determination process, the attribute data of all nodes i1 to i15 constituting the vehicle body analysis model I is set to air. Subsequently, the nodes i1 to i6, i10 to i15 located at the ends are set as boundary nodes (boundary elements), and as shown in FIGS. 5B and 6B, the boundary nodes i1 to i6, i10 to i10 are set. The attribute data of i15 is changed to the electrodeposition liquid (boundary setting step). The node located at the end means a node located at an edge portion of the vehicle body 10, that is, a node located at the edge of the panel member or the edge of the hole formed in the panel member. It is a node that contacts the electrodeposition solution unconditionally when submerged in the tank 11. In other words, the node located at the end is a node that is not surrounded by the surface elements, that is, a node that is not shared by the four surface elements when the surface element is formed of a quadrangle.

  Subsequently, as shown in FIG. 6B, boundary nodes to be analyzed are set from a plurality of nodes, and adjacent nodes (adjacent elements) adjacent to the boundary nodes are set. That is, when the node i6 is set as the boundary node to be analyzed, the node i7 adjacent to the node i6 is set as the adjacent node. When the node i10 is set as the boundary node to be analyzed, the node i9 adjacent to the node i10 is set as the adjacent node. When the adjacent nodes are set in this way, the gas-liquid determination is executed for the adjacent nodes (gas-liquid determination step). Hereinafter, after the gas-liquid determination of the adjacent node i7 will be described, the gas-liquid determination of the adjacent node i9 will be described.

FIGS. 7A to 7C are explanatory diagrams showing a procedure for performing a gas-liquid determination on the adjacent node i7. As shown in FIG. 7A, a bubble model (for example, a diameter of 2 mm) attached to the work surface between the boundary node i6 and the adjacent node i7 is set (bubble setting step), and the buoyancy Fu acting on the bubble model is set. Is calculated. Further, the inclination angle α of the work surface with respect to the horizontal direction is calculated based on the coordinate values of the boundary node i6 and the adjacent node i7. Based on the buoyancy Fu and the inclination angle α, a buoyancy component force Fup in a direction parallel to the work surface is calculated (buoyancy component force calculation step). This buoyancy component force Fup is a force for moving the bubble model toward the adjacent node i7. Further, Fuv shown in FIG. 7A is a buoyancy component in a direction perpendicular to the work surface. In calculating the buoyancy Fu, for example, the following formula (1) can be used. For calculating the buoyancy component force Fup, for example, the following formula (2) can be used. Is possible. ρw is the density of the electrodeposition liquid, ρa is the density of air, V is the volume of the bubble model, and g is the acceleration of gravity.
Fu = (ρw−ρa) × V × g (1)
Fup = Fu × sin α (2)
Subsequently, as shown in FIG. 7B, the flow direction and flow velocity of the electrodeposition liquid acting on the adjacent node i7 are read by referring to a predetermined database based on the coordinate value of the adjacent node i7, and the bubble model is obtained. The flow thrust Fl of the acting electrodeposition liquid is calculated. Here, FIG. 8 is a schematic diagram showing an example of a database referred to when the flow thrust Fl is calculated. As shown in FIG. 8, the vehicle body analysis model and its periphery are partitioned into a plurality of regions, and data D11 to DnN indicating the flow direction and flow velocity of the electrodeposition liquid are stored for each region. When the flow thrust Fl that the electrodeposition liquid pushes the bubble model is calculated with reference to such a database, the thrust component force Flp in the direction parallel to the workpiece surface is calculated based on the flow thrust Fl and the inclination angle α. (Thrust component force calculation step). This thrust component force Flp is a force for moving the bubble model toward the boundary node i6. Further, Flv shown in FIG. 7B is a thrust component in a direction perpendicular to the work surface. When calculating the flow thrust Fl, for example, the following equation (3) can be used, and when calculating the thrust component force Flp, for example, the following equation (4) can be used. Is possible. S is the pressure receiving area (cross-sectional area) of the bubble model, and vw is the flow rate of the electrodeposition liquid.
^{Fl = S × ρw × vw 2} /2 ... (3)
Flp = Fl × cos α (4)
Next, as shown in FIG. 7C, the resultant force (Fup + Flp) acting on the bubble model is calculated based on the buoyancy component force Fup and the thrust component force Flp (the resultant force calculation step). In the case shown in the figure, since the acting directions of the thrust component force Flp and the buoyancy component force Fup are opposite and the buoyancy component force Fup is larger than the thrust component force Flp, the bubble model has an adjacent node i7. The resultant force is acting in the direction to go. The resultant force acting on the bubble model as a scalar quantity is | Fup-Flp |. Subsequently, in order to determine whether or not the attribute data of the adjacent node i7 is an electrodeposition liquid, whether or not the resultant force (Fup + Flp) acting on the bubble model exceeds the adhesion force Fs of the bubble model adhering to the work surface Is determined (determination step). The bubble model adhesion force Fs is a drag force acting in the direction opposite to the moving direction when the bubble model is moved, and is a force set in advance based on the surface tension or intermolecular force of the electrodeposition liquid. It is. When the resultant force acting on the bubble model exceeds the adhesion force (| Fup−Flp |> Fs), the bubble model moves and comes out, so that the attribute data of the adjacent node i9 is determined as the electrodeposition liquid. Is done. On the other hand, when the resultant force acting on the bubble model does not exceed the adhesive force (| Fup−Flp | ≦ Fs), the bubble model is stopped as it is, so that the attribute data of the adjacent node i9 is determined to be air. . In the illustrated case, since the resultant force (| Fup−Flp |) is less than the adhesion force Fs, the attribute data of the adjacent node i7 is maintained as air.

  Subsequently, the gas-liquid determination of the adjacent node i9 will be described. FIGS. 9A to 9C are explanatory diagrams illustrating a procedure for performing a gas-liquid determination on the adjacent node i9. As shown in FIG. 9A, a bubble model (for example, 2 mm in diameter) attached to the workpiece surface between the boundary node i10 and the adjacent node i9 is set, and the buoyancy Fu acting on the bubble model is calculated. Further, the tilt angle α of the work surface with respect to the horizontal direction is calculated based on the coordinate values of the boundary node i10 and the adjacent node i9. Based on the buoyancy Fu and the inclination angle α, the buoyancy component force Fup in the direction parallel to the workpiece surface is calculated. This buoyancy component force Fup is a force for moving the bubble model toward the boundary node i10. In addition, Fuv shown to Fig.9 (a) is a buoyancy component force of the direction perpendicular | vertical to a workpiece | work surface.

  Subsequently, as shown in FIG. 9B, the flow direction and flow velocity of the electrodeposition liquid acting on the adjacent node i9 are read by referring to the database of FIG. 8 based on the coordinate value of the adjacent node i9, The flow thrust Fl of the electrodeposition liquid acting on the model is calculated. When the flow thrust Fl is calculated in this way, the thrust component force Flp in the direction parallel to the workpiece surface is calculated based on the flow thrust Fl and the inclination angle α. This thrust component force Flp is a force for moving the bubble model toward the adjacent node i9. In addition, Flv shown in FIG.9 (b) is a thrust component force of the direction perpendicular | vertical to a workpiece | work surface.

  Next, as shown in FIG. 9C, the resultant force (Fup + Flp) acting on the bubble model is calculated based on the buoyancy component force Fup and the thrust component force Flp. In the case shown in the figure, since the acting direction of the thrust component force Flp and the buoyancy component force Fup is opposite and the thrust component force Flp is larger than the buoyancy component force Fup, the bubble model has an adjacent node i9. The resultant force is acting in the direction to go. The resultant force acting on the bubble model as a scalar quantity is | Fup-Flp |. Subsequently, in order to determine whether or not the attribute data of the adjacent node i9 is an electrodeposition liquid, whether or not the resultant force (Fup + Flp) acting on the bubble model exceeds the adhesion force Fs of the bubble model adhering to the work surface. Is determined. In the case shown in the figure, the resultant force (| Fup−Flp |) exceeds the adhesion force Fs, and the bubble model moves and escapes, so that the attribute data of the adjacent node i9 is changed from air to the electrodeposition liquid. become.

  As described above, when the attribute data of the adjacent node i9 is changed from the air to the electrodeposition liquid, the adjacent node i9 is set as a new boundary node (boundary update step). Then, the node i8 adjacent to the boundary node i9 is set as the adjacent node, and the same gas-liquid determination is executed for the adjacent node i8. Such gas-liquid determination is repeated until there are no unanalyzed adjacent nodes, and attribute data of all the nodes constituting the vehicle body analysis model is divided into electrodeposition liquid or air. In addition, the result of the gas-liquid determination regarding all the nodes is output to the display device 15 through the post processing unit 18 of the arithmetic device 13. In the post processing unit 18, for example, a process is performed in which the nodes that are in contact with the electrodeposition liquid and the nodes that are in contact with the air are classified and expressed by hue, shade, or the like.

  Here, FIG. 10A is an explanatory diagram showing a gas-liquid determination result of the vehicle body analysis model I by a conventional simulation method or simulation program that does not consider the flow thrust Fl. FIG. 10B is an explanatory diagram showing the gas-liquid determination result of the vehicle body analysis model I by the simulation method and simulation program of the present invention in consideration of the flow thrust Fl. 11A is an explanatory view showing the vehicle body analysis model I along the line AA in FIG. 10A, and FIG. 11B is along the line AA in FIG. 10B. FIG.

  First, as shown in FIGS. 10 (a) and 11 (a), when the flow of the electrodeposition liquid is not considered, that is, when only the vertical positional relationship between the nodes is considered, the vehicle body analysis model I , The attribute data of all the nodes i1 to i15 is determined as the electrodeposition liquid. That is, since the vehicle body analysis model I does not have a concave shape that opens downward, the vehicle body analysis model I is determined to have no air pockets. On the other hand, as shown in FIG. 11 (a) and FIG. 11 (a), when the flow of the electrodeposition liquid is taken into consideration, air that tends to escape upward due to buoyancy is pushed back by the flowing electrodeposition liquid. Thus, it is possible to derive a correct result that an air pocket is generated at the node i7.

  Hereinafter, the procedure for predicting the air reservoir will be briefly described with reference to a flowchart. FIG. 12 is a flowchart showing a procedure for predicting air accumulation. As shown in FIG. 12, in step S1, the attribute data of all nodes constituting the vehicle body analysis model is set to air. Subsequently, in step S2, the node located at the end is set as the boundary node, and in step S3, the attribute data of the boundary node is changed to the electrodeposition liquid (boundary setting step). In subsequent step S4, it is determined whether or not there is an unanalyzed boundary node with respect to the presence or absence of an adjacent node described later. If there is an unanalyzed boundary node in step S4, the process proceeds to step S5, where the boundary node to be analyzed is set. In subsequent step S6, it is determined whether there is an adjacent node adjacent to the boundary node. In step S6, when there is an adjacent node, the process proceeds to step S7, and the gas-liquid determination is performed on the adjacent node (gas-liquid determination step).

  Here, FIG. 13 is a flowchart showing in detail the procedure of gas-liquid determination in step S7. As shown in FIG. 13, the coordinate value of the boundary node is read in step S11, and the coordinate value of the adjacent node is read in step S12. In step S13, the flow direction and flow velocity of the electrodeposition liquid are read with reference to the database based on the coordinate values of the adjacent nodes. In subsequent step S14, the adhesion force Fs of the bubble model adhering to the workpiece surface between the boundary node and the adjacent node is read (bubble setting step). In step S15, the tilt angle α of the work surface is calculated based on the coordinate values of the boundary node and the adjacent node. In step S16, a buoyancy component force Fup in a direction parallel to the work surface is calculated based on the buoyancy Fu acting on the bubble model and the inclination angle α (buoyancy component force calculation step). In step S17, a thrust component force Flp in a direction parallel to the work surface is calculated based on the flow thrust Fl acting on the bubble model and the inclination angle α (thrust component force calculating step). Subsequently, in step S18, a resultant force (Fup + Flp) acting on the bubble model is calculated based on the buoyancy component force Fup and the thrust component force Flp (a resultant force calculation step). In the subsequent step S19, the resultant force acting on the bubble model (the resultant force = | Fup + Flp | is applied when the buoyancy component force Fup and the thrust component force Flp are applied in the same direction, and the resultant force = | Fup−Flp | is applied when applied in the opposite direction). It is determined whether or not the wearing force Fs is exceeded (determination step). If it is determined in step S19 that the resultant force (Fup + Flp) exceeds the adhesion force Fs, the process proceeds to step S20, and the attribute data of the adjacent node is changed to the electrodeposition liquid. On the other hand, when it is determined in step S19 that the resultant force (Fup + Flp) is less than the adhesion force Fs, the process proceeds to step S21, and the attribute data of the adjacent nodes is maintained as air.

  As described above, when the gas-liquid determination for the adjacent node is completed, the process proceeds to step S8 in FIG. 12, and it is determined whether or not the attribute data of the adjacent node is the electrodeposition liquid. If it is determined in step S8 that the attribute data of the adjacent node is the electrodeposition liquid, the process proceeds to step S9, and the adjacent node changed to the electrodeposition liquid is set as a new boundary node (boundary update step). ). And it returns to step S4 again and a gas-liquid determination is performed about an unanalyzed boundary node. On the other hand, if it is determined in step S8 that the attribute data of the adjacent node is air, the process directly returns to step S4, and the gas-liquid determination is performed for the unanalyzed boundary node. In this way, the gas-liquid determination from step S4 is repeated until there is no unanalyzed boundary node, and the attribute data of all nodes constituting the vehicle body analysis model is divided into the electrodeposition liquid and air. .

  As described so far, in the present invention, since the presence or absence of the air pool is determined in consideration of the flow of the electrodeposition liquid, the prediction accuracy of the air pool can be improved. In addition, since the influence of the electrodeposition liquid on the air pool is calculated using the bubble model, it is not necessary to prepare a large-scale database, and the operation cost can be greatly reduced.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above description, the gas-liquid determination is executed for the node element of the vehicle body analysis model. However, the present invention is not limited to this, and the gas-liquid determination may be executed for the surface element of the vehicle body analysis model. In this case, after setting the representative points of the surface elements (for example, the center of gravity, inner center, outer center, etc.), the inclination angle α is calculated using the coordinate data of the representative points, and the coordinate data is used. Therefore, the flow direction and flow velocity of the electrodeposition liquid are required. In the above description, the diameter dimension of the bubble model is set to 2 mm. However, the diameter is not limited to this value, and may be appropriately changed according to the vehicle body specification, the processing tank specification, and the like.

  In the above description, the vehicle body 10 is cited as a workpiece. However, the present invention is not limited to this, and other components such as a case may be used as the workpiece. Further, in the illustrated case, the surface shape of the panel member is represented by a rectangular surface element, but the present invention is not limited to this, and the analysis model may be configured by using a surface element such as a triangle or a pentagon. . Although the electrodeposition coating process has been described as an example, the simulation method and simulation program of the present invention may be applied to a simple dipping coating process, and plating that forms a metal film on a workpiece. You may apply with respect to a process.

10 Body (work)
I Car body analysis model (analysis model)
i1 to i15 Node elements (elements)
Fs Adhesive force Fu Buoyant force Fup Buoyant component force Fl Flow thrust Fup Thrust component force Fup + Fup Combined force

Claims (8)

A simulation method for predicting air accumulation when a workpiece is submerged in a processing solution,
A boundary setting step for setting an element located at an end as a boundary element in contact with the processing liquid from a plurality of elements constituting the analysis model of the workpiece;
A gas-liquid determination step of extracting an adjacent element adjacent to the boundary element from a plurality of elements constituting the workpiece analysis model and determining whether the adjacent element is in contact with the processing liquid or air. ,
The gas-liquid determination step includes
A bubble setting step for setting a bubble model that adheres to the work surface between the boundary element and the adjacent element with a predetermined adhesion force;
A buoyancy component force calculating step for calculating a buoyancy component force in a direction parallel to the work surface based on the buoyancy force acting on the bubble model;
A thrust component calculating step for calculating a thrust component in a direction parallel to the workpiece surface based on a flow thrust of the processing liquid acting on the bubble model;
A resultant force calculating step of adding the buoyant component force and the thrust component force to calculate a resultant force acting in a direction parallel to the work surface with respect to the bubble model;
A step of determining that the adjacent element is in contact with the treatment liquid when the resultant force exceeds the adhesion force, and a step of determining that the adjacent element is in contact with air when the resultant force is less than the adhesion force. A simulation method characterized by that. The simulation method according to claim 1,
A boundary update step of setting the adjacent element as a new boundary element when it is determined that the adjacent element is in contact with the processing liquid;
In the gas-liquid determination step, an adjacent element adjacent to a newly set boundary element is extracted, and it is determined whether the adjacent element is in contact with the processing liquid or air. The simulation method according to claim 1 or 2,
The simulation method according to claim 1, wherein the flow thrust of the treatment liquid acting on the bubble model is obtained by referring to a database storing the flow direction and flow velocity of the treatment liquid for each coordinate of the analysis model. In the simulation method according to any one of claims 1 to 3,
The element constituting the analysis model is a plurality of surface elements that divide the surface shape of the workpiece, or a plurality of node elements provided at vertices of the surface elements. A simulation program for predicting air accumulation when a workpiece is submerged in a processing solution,
A boundary setting step for setting an element located at an end as a boundary element in contact with the processing liquid from a plurality of elements constituting the analysis model of the workpiece;
A gas-liquid determination step of extracting an adjacent element adjacent to the boundary element from a plurality of elements constituting the workpiece analysis model and determining whether the adjacent element is in contact with the processing liquid or air. ,
The gas-liquid determination step includes
A bubble setting step for setting a bubble model that adheres to the work surface between the boundary element and the adjacent element with a predetermined adhesion force;
A buoyancy component force calculating step for calculating a buoyancy component force in a direction parallel to the work surface based on the buoyancy force acting on the bubble model;
A thrust component calculating step for calculating a thrust component in a direction parallel to the workpiece surface based on a flow thrust of the processing liquid acting on the bubble model;
A resultant force calculating step of adding the buoyant component force and the thrust component force to calculate a resultant force acting in a direction parallel to the work surface with respect to the bubble model;
A step of determining that the adjacent element is in contact with the treatment liquid when the resultant force exceeds the adhesion force, and a step of determining that the adjacent element is in contact with air when the resultant force is less than the adhesion force. A simulation program characterized by that. The simulation program according to claim 5, wherein
A boundary update step of setting the adjacent element as a new boundary element when it is determined that the adjacent element is in contact with the processing liquid;
The gas-liquid determination step extracts an adjacent element adjacent to a newly set boundary element, and determines whether the adjacent element is in contact with the processing liquid or air. The simulation program according to claim 5 or 6,
A simulation program characterized in that the flow thrust of the processing liquid acting on the bubble model is obtained with reference to a database storing the flow direction and flow velocity of the processing liquid for each coordinate of the analysis model. In the simulation program according to any one of claims 5 to 7,
The simulation program characterized in that the elements constituting the analysis model are a plurality of surface elements that divide the surface shape of the workpiece, or a plurality of node elements provided at the vertices of the surface elements.

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