JP5774940B2 - Simulation method and simulation program - Google Patents

Description

  The present invention relates to a simulation technique for setting the size of a through hole to be added to a workpiece when the thickness of a film formed on the workpiece by dipping is less than a predetermined value.

  In electrodeposition coating, plating, and the like, it is possible to form a uniform coating film, a metal layer, or the like on the workpiece surface by sinking the workpiece in a processing tank in which a processing solution is stored and applying power. In such electrodeposition coating or the like, it is important to form a film with a thickness equal to or greater than a predetermined reference value from the viewpoint of ensuring the rust prevention performance of the workpiece. In addition, since the thickness of the film formed on the workpiece depends on the current density of the workpiece surface due to the workpiece structure, it is important to understand the workpiece structure to obtain an appropriate coating at the design stage. ing. Therefore, a simulation technique has been developed in which the thickness of the coating is predicted in advance to verify the workpiece structure (see, for example, Patent Document 1).

JP 2003-41395 A

  By the way, when the thickness of the coating does not reach the reference value, a through hole is added to a region where the thickness of the coating is insufficient. By forming this through hole, the fluidity of the treatment liquid can be improved, the current density on the workpiece surface can be increased, and the thickness of the coating can be improved. The processing position and size of the through hole are determined by trial and error while repeating the simulation, which increases the development cost. Moreover, adding a through hole to the workpiece causes a decrease in the strength of the workpiece. For this reason, it is necessary to verify the through-hole determined from the viewpoint of the film thickness again from the viewpoint of the work strength, which also increases the development cost.

  The objective of this invention is setting the magnitude | size of the through-hole added to a workpiece | work, suppressing development cost.

  The simulation method of the present invention is a simulation method that is executed by a computer and sets the size of a through-hole added to the workpiece when the thickness of a film formed on the workpiece by dipping is below a predetermined value. For each element constituting the analysis model of the workpiece, a film thickness calculation step for calculating the thickness of the coating film formed by dipping treatment, and a film thickness shortage region in which the thickness of the coating film falls below a predetermined value from the analysis model Extracting and extracting the thinnest element of the coating as a hole processing element for each of the film thickness insufficiency regions, and the through hole based on the stress acting on the hole processing element during the strength test of the workpiece And a through hole setting step for setting the size of.

  The simulation method of the present invention is characterized in that, in the through hole setting step, the through hole is set larger as the stress is smaller, while the through hole is set smaller as the stress is larger.

  The simulation method of the present invention is characterized in that, in the through hole setting step, a processing position of the through hole is set in the hole processing element.

  The simulation method of the present invention has a model construction step of reconstructing the analysis model, reflecting the through-hole set by the through-hole setting step, until the lack of the film thickness shortage region from the analysis model, The film thickness calculation step, the element extraction step, the through hole setting step, and the model construction step are repeated.

  In the simulation method of the present invention, the workpiece is a vehicle body, and the stress is a stress acting during a collision test of the vehicle body.

The simulation program of the present invention is a simulation program for causing a computer to set the size of the through hole added to the workpiece when the thickness of the film formed on the workpiece by the dipping process is less than a predetermined value. In the computer, for each element constituting the workpiece analysis model, a film thickness calculating step for calculating the thickness of the film formed by dipping treatment, and a film thickness deficient region where the thickness of the film is less than a predetermined value. Extracted from the analysis model, based on the element extraction step of extracting the thinnest element of the coating as a hole machining element for each of the insufficient film thickness regions, and the stress acting on the hole machining element during the strength test of the workpiece a through hole setting step of setting the size of the through hole, thereby executing, characterized in that.

  The simulation program of the present invention is characterized in that, in the through hole setting step, the through hole is set larger as the stress is smaller, and the through hole is set smaller as the stress is larger.

  The simulation program of the present invention is characterized in that, in the through hole setting step, a processing position of the through hole is set in the hole processing element.

Simulation program of the present invention, the computer, the reflecting said through-hole is set by the through-hole setting step, the model construction step of reconstructing the analytical model, to execution, to the computer, from the analysis model the film up to a thickness insufficient area is eliminated, the film thickness calculation step, the element extracting step, the through-hole setting step and repeat the model construction step is executed, it is characterized.

  The simulation program of the present invention is characterized in that the workpiece is a vehicle body, and the stress is a stress acting during a collision test of the vehicle body.

  According to the present invention, an insufficient film thickness region in which the thickness of the coating is less than a predetermined value is extracted from the analysis model, and the thinnest element of the coating is extracted as a hole machining element for each insufficient film thickness region. The size of the through hole is set based on the stress acting on the machining element. Therefore, the size of the through hole can be set while considering the work strength, and even if a through hole is added from the viewpoint of securing the thickness of the coating, unnecessary reduction in the work strength can be avoided. It becomes possible. Thereby, a design change for recovering the work strength can be avoided, and the work development cost can be suppressed.

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 a flowchart which shows an example of the procedure which calculates coating-film thickness. (a)-(c) is explanatory drawing which shows roughly the process of calculating coating-film thickness. It is a flowchart which shows an example of the procedure which sets an electrodeposition hole. (a)-(c) is explanatory drawing which shows roughly the process of setting an electrodeposition hole. It is explanatory drawing which shows an example of the table data referred in the setting process of an electrodeposition hole. It is explanatory drawing which shows an example of the setting result of the processing position of an electrodeposition hole, and the electrodeposition hole diameter. It is explanatory drawing which shows an example of the formation method of the electrodeposition hole with respect to a vehicle body analysis model.

  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 (immersion processing) on a vehicle body 10 that is a workpiece, a treatment tank 11 in which an electrodeposition liquid is stored is installed in the electrodeposition coating process. A rail 12 is installed above the processing tank 11, and the vehicle body 10 is suspended from a hanger 13 that travels on the rail 12. A bus bar 14 is installed along the rail 12, and an electrode 15 is installed at the bottom of the processing tank 11. Furthermore, a power supply device 16 is installed in the electrodeposition coating process, and the negative terminal of the power supply device 16 is connected to the bus bar 14, while the positive terminal of the power supply device 16 is connected to the electrode 15. The vehicle body 10 and the bus bar 14 are electrically connected via a hanger 13.

  In this electrodeposition coating process, the vehicle body 10 is subjected to pretreatment such as degreasing and surface adjustment, and then the vehicle body 10 is submerged in the treatment tank 11 and energized between the vehicle body 10 and the electrode 15. A coating film (film) is formed on the 10 outer panels and the inner panel. In this electrodeposition coating, from the viewpoint of securing the rust prevention performance of the vehicle body 10, it is necessary that the thickness of the coating film (coating film thickness) exceeds a predetermined reference value. In addition, since the coating thickness is determined according to the current density on the surface of the vehicle body, electrodeposition holes (through holes) are formed in each part of the vehicle body in order to appropriately form the coating film on the vehicle body 10 having a complicated structure. Thus, there is a need for a vehicle body structure in which the electrodeposition liquid flows evenly into each part of the vehicle body by increasing the fluidity of the electrodeposition liquid.

  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 apparatus 20, and a simulation method and a simulation program are executed by the simulation apparatus 20. As shown in FIG. 2, a simulation device (computer) 20 constituted by a personal computer or the like includes an arithmetic device 21 constituted by a CPU, a memory, etc., an input device 22 such as a keyboard, a display device 23 such as a liquid crystal display, a magnetic A storage device 24 such as a disk is provided. The simulation apparatus 20 may be configured using a single computer such as a personal computer, or may be configured using a plurality of computers connected to each other via a network.

  The storage device 24 of the simulation apparatus 20 stores a vehicle body analysis model (analysis model) M1 in which the entire vehicle body is represented by a mesh. Here, FIG. 3 is a schematic diagram showing the vehicle body analysis model M1. As shown in the enlarged portion of FIG. 3, the vehicle body analysis model M1 includes a plurality of elements that divide the surface shape of the vehicle body 10 and nodes provided at the vertices of the elements. The vehicle body analysis model M1 includes number data of panel members constituting the vehicle body analysis model M1, number data of elements and nodes included in each panel member, coordinate data representing the center of gravity of each element, coordinate data of each node, and the like. It is stored in the storage device 24 in the form. As the vehicle body analysis model M1, it is possible to use the vehicle body analysis model M1 used for collision deformation simulation or the like.

  The arithmetic unit 21 is provided with a coating film thickness calculation unit 25, which calculates the coating film thickness X for each element constituting the vehicle body analysis model M1 (film thickness calculation step). . Here, FIG. 4 is a flowchart showing an example of a procedure for calculating the coating film thickness X. 5A to 5C are explanatory views schematically showing a process of calculating the coating film thickness X. FIG. In addition, the calculation procedure itself of the coating film thickness X is a well-known technique, and will be schematically described with reference to FIGS. First, as shown in FIG. 4, initial setting is performed in step S1. In step S1, the vehicle body analysis model M1 and the electrodeposition tank analysis model M2 are read, and boundary conditions, calculation conditions, and the like necessary for analysis are set. As shown in FIG. 5A, the electrodeposition tank analysis model M2 is an analysis model in which the electrodeposition liquid in the electrodeposition tank is expressed by a mesh, like the vehicle body analysis model M1.

  In step S2, the time t is advanced by Δt, and the boundary condition (electrode voltage or the like) at the time t is updated in the subsequent step S3. In step S4, by solving a predetermined potential diffusion equation using a finite volume method, a finite element method, a finite difference method or the like, the potential distribution in the electrodeposition tank is changed as shown in FIG. Calculated. Subsequently, in step S5, the current density on the panel surface is calculated based on the potential distribution in the electrodeposition tank while considering the film thickness resistance of the paint adsorbed on the panel surface. In step S6, the coating amount ΔX on the panel surface is calculated based on the current density on the panel surface by using a prediction formula between the current density and the coating thickness that has been confirmed in advance from a basic experiment or the like. . Subsequently, in step S7, the coating film thickness X at the current time t is calculated by adding the current coating film deposition amount ΔX to the previous coating film thickness X, as shown in FIG. Next, in step S8, it is determined whether or not to finish the analysis of the coating film thickness X by comparing the current time t with the analysis end time tEND. If it is determined in step S8 that the time t has reached the analysis end time tEND, the process proceeds to step S9, where the coating film thickness X is output and the routine is exited. On the other hand, if it is determined in step S8 that the time t has not reached the analysis end time tEND, steps S2 to S7 are repeatedly executed until the time t reaches the analysis end time tEND.

  Thus, when the coating film thickness X is calculated for each element of the vehicle body analysis model M1 in the initial state, it is determined whether or not the coating film thickness X exceeds a predetermined reference value (predetermined value). When the coating thickness X is less than the reference value, the electrodeposition hole increases the fluidity of the electrodeposition solution in order to increase the inflow of the electrodeposition solution into the insufficient region of the coating thickness X and increase the coating thickness. Is formed in the vehicle body analysis model M1. Therefore, the electrodeposition hole setting unit 26 provided in the arithmetic unit 21 sets the machining position and the electrodeposition hole diameter (size) of the electrodeposition hole to be added to the vehicle body analysis model M1. Hereinafter, a procedure for setting the electrodeposition hole processing position and the electrodeposition hole diameter will be described. Here, FIG. 6 is a flowchart showing an example of a procedure for setting an electrodeposition hole. FIGS. 7A to 7C are explanatory views schematically showing a process of setting an electrodeposition hole. FIG. 8 is an explanatory diagram showing an example of table data referred to in the electrodeposition hole setting process, and FIG. 9 is an explanatory diagram showing an example of the electrodeposition hole machining position and electrodeposition hole diameter setting result. is there. For ease of explanation, FIGS. 7 and 8 show a simplified vehicle body analysis model M1a.

  First, as shown in FIG. 6, in step S10, the coating thickness X is calculated for each element according to the flowchart of FIG. 4 described above. Subsequently, in step S11, it is determined whether or not the coating film thickness X satisfies a reference value (for example, 20 μm) by comparing the coating film thickness X with a predetermined reference value for each element. If it is determined in step S11 that the coating film thickness X is greater than or equal to the reference value for all elements, the routine exits because no further electrodeposition hole setting is required. On the other hand, if it is determined in step S11 that the coating film thickness X is less than the reference value for one or more elements, the process proceeds to step S12, and an insufficient film thickness region is extracted from the vehicle body analysis model M1 (element extraction). Step). The film thickness insufficiency region is a region constituted by adjacent elements while the coating film thickness X is below the reference value, as shown by light ink (reference numerals A1, A2) in FIG. In FIG. 7A, the numbers shown for each element mean the coating thickness [μm] calculated for each element.

  Subsequently, in step S13, a hole processing element is extracted for each region where the film thickness is insufficient (element extraction step). This drilling element is an element having the thinnest coating thickness X in each of the insufficient film thickness areas A1 and A2, as indicated by reference numerals B1 and B2 in FIG. In the subsequent step S14, the machining position of the electrodeposition hole is set in the extracted hole machining element (through hole setting step). As shown in FIG. 7C, the gravity center position C1 of the hole machining element B1 is set as the machining position of the electrodeposition hole H1 formed in the hole machining element B1. Further, the center-of-gravity position C2 of the hole machining element B2 is set as the machining position of the electrodeposition hole H2 formed in the hole machining element B2. That is, the machining positions (center positions) of the electrodeposition holes H1 and H2 are set in the area of the hole machining elements B1 and B2. In the case shown in the figure, the center positions of the electrodeposition holes H1 and H2 and the gravity center positions C1 and C2 of the hole machining elements B1 and B2 coincide with each other.

  In step S15, the stress is read for each extracted hole processing element by referring to predetermined map data as shown in FIG. 7B. That is, in the case shown in FIG. 7, 50 MPa is read as the stress of the drilling element B1, and 110 MPa is read as the stress of the drilling element B2. The stress read in step S <b> 14 is a stress that acts on each element during a collision test that is a strength test of the vehicle body 10. In step S14, map data indicating the stress for each element is created in advance by a collision test simulation or the like, and the stress acting on the hole machining element is read by referring to this map data. In FIG. 7B, the numbers shown for each element mean the stress [MPa] acting on each element.

  Next, in step S16, by referring to predetermined table data as shown in FIG. 8, the electrodeposition hole diameter (radius of electrodeposition hole) is set based on the stress (through hole setting step). As shown in FIG. 8, the smaller the stress acting on the element, the larger the electrodeposition hole diameter, and the larger the stress acting on the element, the smaller the electrodeposition hole diameter. For example, in the case shown in FIGS. 7 and 8, the electrodeposition hole diameter is set to 10 mm because the stress is 50 MPa for the electrodeposition hole H1 of the hole machining element B1. Further, the electrodeposition hole diameter of the electrodeposition hole H2 of the hole machining element B2 is set to 4 mm because the stress is 110 MPa.

  Then, as shown in FIG. 9, when the electrodeposition hole processing position and the electrodeposition hole diameter are set for all the film thickness deficient regions of the vehicle analysis model, the process proceeds to step S17 in FIG. The provided model construction unit 27 reconstructs the vehicle body analysis model M1 reflecting the electrodeposition holes by forming electrodeposition holes in the vehicle body analysis model M1 (model construction step). Here, FIG. 10 is an explanatory view showing an example of a method of forming an electrodeposition hole for the vehicle body analysis model M1. As shown in FIG. 10, when forming an electrodeposition hole H having an electrodeposition hole diameter R with respect to the center of gravity position C of the hole machining element B, first, a spherical surface S having a radius R is set around the center of gravity position C. . Then, by cutting the boundary line L between the hole machining element B and the spherical surface S, an electrodeposition hole H having an electrodeposition hole diameter R is formed at the center of gravity C of the hole machining element B. Thereby, the electrodeposition hole H can be easily formed without being affected by the inclination of the hole machining element B.

  Thus, when the vehicle body analysis model M1 reflecting the electrodeposition hole is reconstructed in step S17, the process returns to step S10, and the coating film thickness X is recalculated for the new vehicle body analysis model M1. The calculation of the coating film thickness X and the reconstruction of the vehicle body analysis model M1 are repeated until there is no film thickness shortage region from the vehicle body analysis model M1, and the vehicle body analysis model M1 that satisfies the coating standard is constructed. Become. Then, the coating thickness X of the completed vehicle body analysis model M1 is output to the display device 23 via the post processing unit 28 of the arithmetic device 21. In the post processing unit 28, for example, a process of expressing the coating film thickness X by dividing it by hue, shading or the like is executed.

  As described so far, in the present invention, since the electrodeposition hole diameter is set based on the stress acting on the hole machining element during the collision test, the electric field strength (vehicle body rigidity) that passes the collision test is ensured. It is possible to set the diameter of the hole. In other words, the diameter of the electrodeposition hole is set to be large for a drilling element to which a small stress is applied, so that the electrodeposition is large for a hole processing element to which a large stress is applied. The hole diameter is set small. In this way, by setting the electrodeposition hole while considering the rigidity of the vehicle body, it is possible to ensure sufficient vehicle body strength even when adding an electrodeposition hole from the viewpoint of securing the coating thickness. Become. Thereby, after adding an electrodeposition hole to the vehicle body 10, it is possible to avoid a design change for securing the vehicle body strength for a collision test, and it is possible to suppress the development cost of the vehicle body 10. In addition, since the element with the thinnest coating thickness is set as the hole processing element in the insufficient film thickness region, and the electrodeposition hole is processed for this hole processing element, the number of electrodeposition holes is suppressed. It is also possible to improve the coating thickness X efficiently.

  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 machining position of the electrodeposition hole is set at the center of gravity position of the hole machining element, but the present invention is not limited to this, and the electrodeposition hole is formed at the inner center point or the outer center point of the hole machining element. The machining position may be set. Further, each element for calculating the coating thickness shown in FIG. 7A and each element for recording the stress shown in FIG. 7B have the same shape and size. However, the present invention is not limited to this, and the shape and size of each element do not have to be the same as long as it is possible to compare the drilling element and the corresponding stress.

  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. In this case, as the stress acting on the drilling element, the stress acting on the drilling element during the case strength test is used. Further, in the illustrated case, the analysis model is configured using triangular elements. However, the present invention is not limited to this, and the analysis model may be configured using elements such as quadrilaterals and pentagons. Note that although electrodeposition coating is described as an example, the simulation method and simulation program of the present invention may be applied to a plating process (immersion process) for forming a metal layer on the workpiece surface.

10 Body (work)
20 Simulation device (computer)
A1, A2 Insufficient film thickness area B1, B2 Drilling elements H1, H2 Electrodeposition holes (through holes)
M1, M1a Body analysis model (analysis model)
X coating thickness (thickness of coating)

Claims (10)

A simulation method that is executed by a computer and sets a size of a through-hole added to the workpiece when the thickness of a film formed on the workpiece by dipping is less than a predetermined value,
For each element constituting the analysis model of the workpiece, a film thickness calculating step for calculating the thickness of the film formed by dipping treatment,
Extracting the film thickness deficient region where the thickness of the coating is below a predetermined value from the analysis model, and extracting the thinnest element of the coating as a hole processing element for each of the film thickness deficient regions;
And a through hole setting step for setting a size of the through hole based on a stress acting on the hole machining element during the strength test of the workpiece. The simulation method according to claim 1,
In the through hole setting step, the through hole is set to be larger as the stress is smaller, while the through hole is set to be smaller as the stress is larger. The simulation method according to claim 1 or 2,
In the through hole setting step, a processing position of the through hole is set in the hole processing element. In the simulation method according to any one of claims 1 to 3,
Reflecting the through-hole set by the through-hole setting step, and having a model construction step for reconstructing the analysis model,
The simulation method, wherein the film thickness calculation step, the element extraction step, the through-hole setting step, and the model construction step are repeated until the insufficient film thickness region disappears from the analysis model. In the simulation method according to any one of claims 1 to 4,
The simulation method, wherein the workpiece is a vehicle body, and the stress is a stress acting during a collision test of the vehicle body. A simulation program for causing a computer to set the size of a through hole to be added to the workpiece when the thickness of the film formed on the workpiece by the dipping process is less than a predetermined value,
In the computer,
For each element constituting the analysis model of the workpiece, a film thickness calculating step for calculating the thickness of the film formed by dipping treatment,
Extracting the film thickness deficient region where the thickness of the coating is below a predetermined value from the analysis model, and extracting the thinnest element of the coating as a hole processing element for each of the film thickness deficient regions;
A through hole setting step for setting the size of the through hole based on the stress acting on the hole machining element during the strength test of the workpiece;
A simulation program characterized by causing The simulation program according to claim 6, wherein
In the through-hole setting step, the simulation program is characterized in that the smaller the stress is, the larger the through-hole is set, while the larger the stress is, the smaller the through-hole is set. The simulation program according to claim 6 or 7,
In the through hole setting step, a processing position of the through hole is set in the hole processing element. In the simulation program according to any one of claims 6 to 8,
The computer reflects the through-hole set by the through-hole setting step and reconstructs the analysis model , and executes a model construction step.
The computer, from the analysis model to the thickness insufficient area is eliminated, the film thickness calculation step, the element extracting step, the through-hole setting step and repeat the model construction step is executed, and characterized by Simulation program. In the simulation program according to any one of claims 6 to 9,
The simulation program, wherein the workpiece is a vehicle body, and the stress is a stress acting during a collision test of the vehicle body.

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