JP4807747B2 - Air pool simulation method and simulation program - Google Patents

Description

  The present invention relates to an air pool simulation method and a simulation program for simulating an air pool generated in a workpiece when a dipping process is performed.

  In general, in the work dipping process in electrodeposition coating or plating, it is important not to cause air pockets (air pockets) in the work in order to form a uniform coating film or plating film. This air pocket is a recess that can be formed when a workpiece having a complicated shape is immersed, for example, if it is a vehicle body such as an automobile, air remains in a space such as a recess such as the inner surface of the hood, the inner surface of the roof, or the lower surface of the floor. If this air pocket is generated, poor coating and poor plating will occur.

  In view of this, a method has been proposed in which a state in which a workpiece is immersed is simulated using a computer to predict the occurrence of air pockets. As a computer simulation of an air pocket, the surface shape of a workpiece is modeled with data of a plurality of elements such as meshes and nodes, and whether the attribute of each element is a gas or a liquid, the feature point of the element (for example, Geometrical methods are known for predicting and evaluating the occurrence of air pockets for the set gravity direction by comparing the positions in the gravity direction between the center of gravity, vertex, inner center, outer center, and centroid). (For example, see Japanese Patent Application No. 2006-19413 by the present applicant).

Further, in Patent Document 1, each surface of a work is divided into an arbitrary number of triangular polygons (triangular elements) based on the vertex coordinate data, and the state change between air and liquid in the immersion bath for each triangular polygon. A method for determining whether or not the surface portion can be an air pocket when the workpiece is simulated and immersed in the immersion bath in the posture of the tank entrance angle is disclosed.
JP 2000-51750 A

  However, in the conventional simulation, it is possible to determine whether or not air pockets are generated. However, in order to examine the immersion posture such as the workpiece hanging posture that minimizes the occurrence of air pockets, It is necessary to set and calculate the direction of gravity for the workpiece. That is, in the conventional simulation, the gravity direction is set first, and then the discrimination calculation between the gas and the liquid is performed. You have to repeat the trial and error while entering once. As a result, for example, the following problems (1) to (3) occur.

(1) Even if multiple hanging positions without air pockets are found, what is the best position (whether it is on the safe side, taking into account the effects of mounting errors and manufacturing variations on the line) It is difficult to make judgments by going to the point.

(2) Even if the simulation by trial and error is repeated, if a fishing posture without air pockets is not found, which posture should be corrected (which posture is the easiest to counter) It is unknown.

(3) Even if there is a fishing posture range without air pockets in the immediate vicinity of the examined fishing posture, the possibility cannot be known.

  In this way, in the conventional simulation, in order to find the optimum immersion posture of the work that minimizes the occurrence of air pockets, it is necessary to repeat a large number of trials and errors, which increases man-hours and costs. In addition, the result obtained by the trial and error is not necessarily the optimum posture.

  The present invention has been made in view of the above circumstances, and an air pool simulation method capable of automatically determining the optimum posture of a work that minimizes the occurrence of air pools in the dipping process without repeating trial and error, and The purpose is to provide a simulation program.

In order to achieve the above object, the simulation method of an air pocket according to the present invention is a computer model of the shape of a work to be dipped by data of a plurality of elements, and based on the posture of the work with respect to the direction of gravity, In a simulation method for a puddle that simulates a puddle by a computer executing a discrimination calculation to determine whether the attribute is gas or liquid, the range in which the posture of the work can be varied is set for the gravity direction with respect to the work Gravity direction update step that specifies the range, updates the gravity direction within the specified setting range by a predetermined step angle, and repeatedly executes the discrimination calculation, and the occurrence status of the air pool and the number of air pool occurrences and elements the increment angle per index data for evaluating representing at least one in the number and size Calculated, optimum attitude of the distribution of the index data separately for each region corresponding to the occurrence of the air pocket, to calculate the optimum orientation of the workpiece from the increment angle corresponding to the optimum region without generation of the air reservoir And a calculating step.

The air pool simulation program according to the present invention models the shape of a workpiece to be dipped with data of a plurality of elements, and the attribute of each element is gas or liquid based on the posture of the workpiece with respect to the direction of gravity. In a simulation program for air traps that can be executed by a computer that simulates air traps by executing discriminant calculation, specify the range in which the posture of the workpiece can be changed as the setting range for the gravity direction with respect to the workpiece. A gravity direction update step in which the gravity direction is updated by a predetermined step angle within the set range and the discrimination calculation is repeatedly executed, and the occurrence state of the air pool is determined by at least the number of the air pools generated, the number of elements, and the size. the index data to be evaluated expressed one by calculating for each of the increments angle, the index The distribution of over data divided for each region corresponding to the occurrence of the air reservoir, and the optimum orientation calculation step of calculating an optimum attitude of the workpiece from the increment angle corresponding to the optimum region without generation of the air reservoir It is characterized by providing.

  According to the present invention, it is possible to automatically obtain the optimum posture of a work that minimizes the occurrence of air accumulation in the dipping process without repeating trial and error, improving simulation efficiency and reducing man-hours and costs. be able to.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 10 relate to a first embodiment of the present invention, FIG. 1 is a basic configuration diagram of a simulation apparatus, FIG. 2 is a schematic explanatory view of a painting line of a vehicle body, FIG. 3 is a schematic perspective view of a floor panel, FIG. 4 is an explanatory diagram showing an analysis model in which the floor panel is divided into a plurality of elements, FIG. 5 is an explanatory diagram showing the gravity direction and the calculation step angle, FIG. 6 is an explanatory diagram showing an example of a post processing mesh, and FIG. FIG. 8 is an explanatory diagram showing an example of post processing, FIG. 8 is an explanatory diagram showing a case where the optimal region is distorted, FIG. 9 is an explanatory diagram showing the distribution of the optimal region of the same area, and FIG. .

  As shown in FIG. 1, the simulation apparatus 1 according to the present embodiment creates an air pocket (air pocket) generated in a work when an immersion process such as electrodeposition coating or plating is performed on a work such as a body shell of an automobile. To simulate. The air pocket simulation apparatus 1 is configured using a single computer such as a microcomputer or a personal computer, or a plurality of computers connected to each other via a network.

  Below, the example which comprises the simulation apparatus 1 with a single computer for convenience is demonstrated. The simulation apparatus 1 as a computer includes an arithmetic device 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, an external storage device 13 such as a magnetic disk and an optical disk, and the like.

  The arithmetic device 10 includes an internal memory such as a CPU, a ROM and a RAM, an input / output interface, and the like, and includes a simulation program stored in an internal ROM, an external storage device 13 and an external storage medium, or a network (not shown) A simulation program loaded from the outside via the communication device is executed by the CPU, and the workpiece (object) to be analyzed instructed via the input device 11 is immersed in the immersion bath in a pseudo manner, and the object is obtained by the immersion. Simulates the air pockets that occur.

  For example, as an application example of the simulation according to the present invention, there is a simulation in which the distribution of the electrodeposition liquid and air during the electrodeposition coating of the vehicle body is numerically analyzed to predict the occurrence of air pockets in the object to be coated. Here, the painting line of the vehicle body will be briefly described with reference to FIG.

  As shown in FIG. 2, a vehicle body body 20 of an automobile configured by joining a plurality of vehicle body panels to each other by welding or the like is transported in a substantially horizontal direction on a painting line while being mounted on a hanger of a transport device 21. The In the painting line, as a pretreatment for electrodeposition coating, the body panel is subjected to treatments such as degreasing, water washing, surface adjustment, film formation, water washing and the like.

  After these processes, the vehicle body 20 descends toward the electrodeposition tank 22 and moves substantially horizontally while being immersed in the electrodeposition liquid 23. In this state, paint is deposited on the vehicle body panel by applying a voltage to the vehicle body 20 and electrodes (not shown) in the electrodeposition tank 22. Thereafter, the vehicle body 20 is pulled up from the electrodeposition tank 22 by the transfer device 21, and the electrodeposition liquid 23 adhering to the vehicle body panel without being electrodeposited is removed by washing.

  The function of the simulation program executed in the arithmetic device 10 can be expressed by the model construction unit 10a, the gravity direction update unit 10b, the air pocket determination unit 10c, and the post processing unit 10d. The arithmetic unit 10 simulates the occurrence of air pockets using a geometric technique based on an analysis model obtained by modeling the shape of an object (work) with data of a plurality of elements, and outputs the simulation result to the display unit 12. Display. The display device 12 may display not only the simulation result but also the simulation process.

  The simulation of the air pocket according to the present invention is executed by using a surface model constructed by dividing the surface shape of an object (work) into a plurality of elements. The simulation is not completed in one simulation but is automatically repeated a plurality of times by changing the immersion posture of the workpiece. By automatically executing a plurality of simulations with the workpiece immersion posture varied, an optimum workpiece immersion posture that minimizes the occurrence of air pockets can be obtained. Below, the air pocket simulation which calculates | requires the optimal fishing posture of the workpiece | work immersed in the paint tank etc. is demonstrated.

  The model construction unit 10a constructs an analysis model by dividing the shape data of the object into a plurality of elements. As a method for constructing the analysis model, a method using a mesh that represents a surface shape of an object divided into a plurality of predetermined shapes, a method of arranging a plurality of nodes (nodes) on the surface of the object, or the like is used. be able to.

  For example, the floor panel 26 as shown in FIG. 3 constituting the vehicle body 20 will be described as an example. As shown in FIG. 4, the floor panel 26 shown in FIG. An analysis model for numerical calculation is constructed by dividing into 29. In the following, an example of constructing an analysis model by using a surface model that expresses the surface shape of an object with a triangular mesh and arranging the mesh data of this surface model in a three-dimensional space will be explained. The process is the same when using nodes.

  Note that the shape of the mesh as an element of the analysis model is not limited to a triangular shape, and may be a rectangular or polygonal shape. Each mesh includes, for example, data such as a mesh number for identifying itself, coordinate values of nodes (nodes) of the mesh with respect to a predetermined reference point (coordinate values on the XYZ coordinate axes in the three-dimensional space), mesh attributes, and the like. Is granted.

  The external storage device 13 stores various data necessary for the air pocket simulation process. For example, the external storage device 13 has a database composed of attribute record groups to which individual identification numbers (record numbers) are assigned for each object, and each attribute record includes a mesh number and a node point. Coordinate values, attribute data, and the like are described in association with each other.

  The gravitational direction update unit 10b designates a setting range centered on the Z axis of the XYZ orthogonal coordinate system fixed to the workpiece, and the gravitational direction according to the calculation step angle when the simulation is repeatedly executed within the designated range. Update. That is, as shown in FIG. 5, the direction of gravity viewed from the XYZ coordinate system fixed to the workpiece is an angle φ with respect to the Z axis, and a deviation angle on the XY plane centered on the Z axis (from the X axis). (Angle) θ, and by changing these angles in increments of calculation increments (Δφ, Δθ), the simulation can be repeated by changing the direction of gravity (that is, changing the posture of the workpiece).

  Note that the calculation step angles (Δφ, Δθ) may be constant values or may be changed for each simulation.

  The air pocket determination unit 10c sets, for each mesh forming the analysis model, either a gas attribute corresponding to an air pocket location or a liquid attribute corresponding to an immersion location such as an electrodeposition liquid. . This mesh attribute is initially set to the gas attribute for all meshes (before immersion), and then the mesh attribute is determined by comparing the height in the Z direction (opposite to gravity) with the adjacent mesh including the initial mesh. Is determined to be liquid or gas (that is, whether to become an air pocket). When it is determined to be liquid, the attribute of the mesh is changed to liquid and the attribute data is rewritten.

  In this embodiment, the determination of the air pocket is based on the premise that the specific gravity of the immersion liquid is larger than the specific gravity of air. That is, when the attribute of a certain mesh is determined, the determination target mesh and the comparison target mesh are compared in height in the Z direction (the direction opposite to gravity). Then, if the comparison target mesh is higher than the determination target mesh and has a liquid attribute, it is determined that the immersion liquid penetrates the relatively low determination target mesh by pushing the air and is filled with the immersion liquid. Thus, the attribute data of the determination target mesh is liquid. On the other hand, when the attribute of the relatively high comparison target mesh is gas, the attribute data of the determination target mesh is not changed, and the comparison is changed and the determination is repeated. Then, this determination is repeated to separate and determine the attributes of all the meshes as liquid and gas, and the gas-liquid boundary line of the air pocket indicated by the presence of the mesh whose attribute is determined as gas is derived. A plurality of gas-liquid boundary lines may be derived.

  The post processing unit 10d performs a visualization process for enabling easy understanding of the simulation result and data output of the simulation result. In the visualization process of the simulation result, for example, the mesh determined as the liquid attribute, the mesh determined as the gas attribute, and the boundary line (gas-liquid boundary line) are classified according to hue, shading, etc. Express the location and size of the occurrence.

  Further, the post processing unit 10d calculates the number of air pockets generated, the number of air pocket surface meshes, the volume of air pockets, etc. for each setting of the direction of gravity as index data for evaluating the occurrence of air pockets, After the simulation within the setting range in the direction of gravity is completed, a process for visualizing these is performed. Note that [area of gas-liquid boundary surface] × [air pocket height] may be calculated as index data instead of the air pocket volume.

  When the index data is visualized, a post processing mesh provided corresponding to the calculation step angle (Δφ, Δθ) in the direction of gravity is used. For example, as shown in FIG. 6A, the post-processing mesh includes an evaluation mesh in which a designated range in the gravity direction projected on the XY plane is divided in accordance with calculation step angles (Δφ, Δθ). As shown in FIG. 6B, an evaluation mesh in which calculation step angles (Δφ, Δθ) are developed around the origin is used.

  Each node point (lattice point) of the post processing mesh is assigned an index value for evaluating the air pocket generation status such as the number of air pockets generated, the number of surface meshes of the air pockets, and the volume of the air pockets. For example, when the number of generated air pockets is used as an index value and no air pocket is generated, the node value “0” is assigned to the corresponding node point, and when one air pocket is generated, the corresponding node When a node value “1” is assigned to a point and two air pockets are generated, the node value “2” is assigned to the corresponding node point. Then, as shown in FIGS. 7A and 7B, the node values of the post processing mesh are divided into the same regions, and the occurrence of air pockets is visualized.

  In addition, in the visualization process that shows the occurrence status of air pockets, the area where the node value is “0” (area where no air pocket occurs) is the optimal area where the optimal posture of the workpiece exists. A correct work posture (optimal work hanging angle) is obtained and its position is identified and displayed.

  Specifically, first, the node value in the partial region of the node value “0” in contact with the boundary line between the region of the node value “0” and the region of the node value “1” is changed from “0” to another numerical value n. Change to For example, if another numerical value n is set in a range of 0 <n <1, and is changed to n = 0.5, the node value “0.5” and the node value “0” are next set. The node value in the partial region of the node value “0” in contact with the boundary line is changed from “0” to “0.5”.

  The above process is sequentially repeated, and the step angle (Δφ, Δθ) in the partial area is averaged one step before the last partial area of the node value “0” disappears. Then, as shown in FIG. 7, the positions corresponding to the averaged step angles are displayed in an overlapped manner within the region with, for example, a red “x” mark. The position (optimum point) of the “×” point display represents the optimum angle of the workpiece fishing posture in the optimum region where no air pocket is generated.

  The reason for narrowing down the optimal area of the node value “0” by dividing the optimal area of the node value “0” into partial areas and narrowing it down is as follows: This is to cope with a case where a plurality of optimum areas having the node value “0” exist in a distributed manner. In other words, by setting the optimal point at the approximate center as far as possible from the boundary with the area where air pockets occur within the optimal area where air pockets do not occur, it is possible to prevent mounting errors on the actual line, manufacturing variations, etc. It is possible to set a fishing posture that is appropriate and safe.

  For example, as shown in FIG. 8, when the shape of the optimum region of the node value “0” is distorted, if the step angle in the entire optimum region is simply averaged, the average value is the node value “0”. There is a possibility that the region is outside the region, that is, the region where the air pocket is generated. Even in such a case, by enclosing the region of the node value “0” from the periphery, it is possible to reliably set the optimum point at a substantially central position within the region of the node value “0”. it can.

  Also, as shown in FIG. 9, when there are a plurality of optimum regions having substantially the same area of the node value “0”, it is desirable to set the optimum angle from the region close to a circle, and nodes having different areas. When there are a plurality of regions having the value “0”, it is desirable to set the optimum angle from the region having the largest possible area. Even in such a case, by enclosing the region of the node value “0” from the periphery, it becomes possible to set an optimum angle in a region having a large area and close to a circular shape. The optimum point can be set at a position as far as possible from the boundary with the region where the air pocket is generated.

  The air pocket simulation process executed by the CPU of the arithmetic unit 10 will be described below with reference to the flowchart of FIG.

  In the simulation program of FIG. 10, first, in step S1, the surface shape of the object is modeled with data of a plurality of elements, and an analysis model for numerical calculation is constructed. This analysis model is constructed by, for example, a model obtained by dividing the surface shape of a workpiece with a plurality of triangular meshes.

  Next, the process proceeds to step S2 to specify a setting range of the gravity direction in the analysis model, and the gravity direction is selected in step S3. This gravitational direction is varied by calculation step angles (Δφ, Δθ) for each simulation (step S7 described later).

  In step S4, all meshes of the analysis model are temporarily set as gas attributes as a simulation of the state in which the periphery before the object is immersed in the electrodeposition liquid or the like is filled with air. Furthermore, initial conditions for separating the mesh into a liquid attribute and a gas attribute are set as a simulation of the initial state in which the object is immersed.

  In the present embodiment, as a condition for determining the mesh attribute in the initial state to be liquid, the mesh in contact with the free edge of the workpiece is set as the initial mesh. The attribute of the initial mesh is changed from gas to liquid. Here, the free edge means the edge portion of the workpiece, that is, the edge portion of the workpiece and the edge portion of the hole formed in the workpiece. The initial mesh is an element that is in contact with the free edge of the workpiece, and the mesh that is in contact with the free edge means that the sides constituting the mesh are in contact with the free edge.

  Note that, as a condition for initially determining the attribute as liquid, a mesh that can be recognized with respect to the work as viewed from the line-of-sight direction above its periphery and above the horizontal may be used as the initial mesh. Even in this case, the processing after the initial mesh determination is the same.

  Next, it progresses to step S5 from step S4, an air pocket determination calculation process is implemented, and generation | occurrence | production of an air pocket is simulated. This air pocket determination calculation process is a process for determining the occurrence of an air pocket by determining the respective attributes by comparing the height of each mesh in the direction opposite to the gravity, and a conventional method can be used. The comparison of the height of each mesh is, for example, the position in the Z direction (direction opposite to gravity) such as the center of gravity, inner center, outer center, and centroid of each mesh, and each vertex of each mesh Is performed by comparing feature points such as the highest vertex (the vertex having the highest position in the Z direction).

  For example, when comparing the positions of the centroid points, the heights of the centroid points in the Z direction of the meshes to be judged and the adjacent meshes are compared, and the centroid points of the adjacent meshes are compared to the centroid points of the judgment subject meshes. If the attribute of the adjacent mesh is liquid, the attribute of the determination target mesh is determined to be liquid. On the other hand, when the barycentric point of the adjacent mesh is lower than the barycentric point of the determination target mesh, the attribute of the determination determination mesh is not changed, and the comparison is changed and the determination is repeated. This determination is performed for all meshes including the initial mesh, the boundary between the mesh having the liquid attribute and the mesh having the gas attribute is detected as a gas-liquid boundary line, and the gas-liquid boundary line is corrected as necessary. I do.

  In addition, the process which corrects a gas-liquid boundary line gives the same attribute to the several boundary line which belongs to one air pocket, for example, and when the height of each boundary line differs, it changes to one horizontal line. Modify it so that it is closer.

  Thereafter, the process proceeds to step S6, the results obtained in one simulation are processed, and the indices such as the number of air pockets generated, the number of air pocket surface meshes, the volume of air pockets, etc. are calculated. save.

  Next, in step S7, the direction of gravity is updated by changing the calculation step angle (Δφ, Δθ) in order to perform a simulation by changing the hanging position of the workpiece. Then, in step S8, it is checked whether or not the gravity direction is within a preset setting range. If it is within the setting range, the process returns to step S4 to re-execute the simulation with the gravity direction changed. The above steps S2, S3 and steps S7, S8 correspond to the gravity update step of the present invention.

  On the other hand, if the gravitational direction exceeds the set range, the update of the gravitational direction is terminated, the process proceeds from step S8 to step S9, post processing is performed, and this simulation program is terminated. In this post processing, as described above, using the indexes such as the number of air pockets generated, the number of surface meshes of the air pockets, the volume of the air pockets, etc., as shown in FIG. The posture is displayed on the display device 12, and the simulation result data is output to a file as necessary. This step S9 corresponds to the optimum posture calculation step of the present invention.

  Based on the simulation results shown in FIG. 7, it is possible to quickly set an optimum fishing posture for a workpiece that does not generate an air pocket, and even if there is no region where no air pocket is generated, a fishing posture that is easy to take measures Can be easily grasped.

  As described above, according to the first embodiment, the optimum posture of the workpiece is automatically obtained as compared with the conventional method of repeating the trial and error while inputting the gravity direction with respect to the workpiece once for each simulation. Even if a plurality of hanging postures without occurrence of air pockets are found, it is possible to easily determine which posture is the best with respect to the influence of the mounting error on the line, manufacturing variations, and the like. Thereby, a simulation efficiency can be improved and a man-hour and expense can be suppressed.

  Next, a second embodiment of the present invention will be described. FIG. 11 is a flowchart of an air pocket simulation program according to the second embodiment of the present invention.

  The second form optimizes the gravitational direction and automatically obtains the optimum fishing position for the first form in which the simulation is repeated the number of times determined from the setting range of the gravitational direction and the calculation step angle.

  The simulation program in the second form is shown in the flowchart of FIG. In this simulation program, steps S11 to S16 are the same as steps S1 to S6 in the simulation program of the first embodiment (see FIG. 10), an analysis model is constructed, the direction of gravity is selected, and initial conditions are set. The air pocket judgment calculation is performed and the calculation result is processed.

  Next, when proceeding from step S16 to step S17, optimization calculation for optimizing the direction of gravity is performed. This optimization calculation is performed, for example, using an optimization method such as a genetic algorithm (GA), and index data for evaluating the occurrence of air pockets with a set range in the specified gravity direction as a constraint. Optimization calculation is performed using the objective function created based on.

  Note that the optimization in this case may be simply to determine the position of the workpiece that has no air pocket, but in this embodiment, it is the most optimal among the multiple positions to be dropped without air pockets. In order to obtain a correct posture, other variables are required in addition to the index data whose value is “0” in the state where no air pocket is generated.

  In the present embodiment, the processing time (CPU time) for discriminant calculation or the number of simulation iterations is used in combination with the index data, which are used as design variables when creating the objective function. This is the posture in which air is most likely to escape when the processing time or number of times required for discrimination calculation is the shortest at multiple posture angles of a workpiece that does not generate air pockets, realizing a state without air pockets reliably and stably. This is because it is considered possible.

Specifically, as shown below, an objective function f is created with the number of air pockets generated and the processing time (CPU time) of air pocket discrimination calculation as design variables, and this objective function f is a constraint condition. The step angle (Δφ, Δθ) at the minimum within the range (set range in the direction of gravity) is the optimum angle for the workpiece fishing posture.
f (n, Ctime) = (n + ζ) · Ctime
Where ζ: constant (0 <ζ ≦ 1)

  That is, in step S18, it is checked whether or not the gravity direction is optimal (the objective function is minimum). If the gravity direction is not optimal (the objective function is not minimum), the gravity direction is updated in step S19 and step S14 is performed. Return to, and execute a simulation in which the updated gravity direction, that is, the workpiece hanging posture is changed.

  On the other hand, when the gravitational direction is optimized (when the objective function is minimized) in step S18, the entire simulation is finished, and the process proceeds from step S18 to step S19 to execute post processing. In this post processing, if air pockets are generated, the number of air pockets generated, the number of surface meshes of the air pockets, the volume of the air pockets, etc. are displayed, and the occurrence status of the air pockets is visualized as necessary. To process.

  In the second embodiment, the above steps S12, S13, and S19 correspond to the gravity direction update step of the present invention, and steps S17, S18, and S20 correspond to the optimum posture calculation step of the present invention.

  In the second mode, as in the first mode, the optimum posture of the workpiece can be automatically obtained without repeating trial and error. In the second mode, however, a post process after a specified number of simulations is waited. Therefore, it is possible to directly obtain the optimal fishing posture and to further improve the simulation efficiency.

The basic block diagram of the simulation apparatus according to the first embodiment of the present invention. Schematic illustration of the car body painting line Schematic perspective view of floor panel Explanatory drawing showing an analysis model that divides the floor panel into multiple elements Same as above, explanatory diagram showing gravity direction and calculation step angle As above, an explanatory diagram showing an example of a mesh for post processing Same as above, explanatory diagram showing an example of post processing As above, an explanatory diagram showing a case where the optimum region is distorted Same as above, explanatory diagram showing the distribution of the optimal area of the same area Same as above, air pocket simulation program flowchart A flowchart of an air pocket simulation program according to the second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Simulation apparatus 10 Arithmetic apparatus 10a Model construction part 10b Gravity direction update part 10c Air pocket determination part 10d Post processing part

Claims (10)

The computer models the shape of the work to be dipped with data of multiple elements, and based on the posture of the work with respect to the direction of gravity, the computer performs discriminant calculation to determine whether the attribute of each element is gas or liquid In the air pool simulation method of simulating the air pool by executing
A gravity direction updating step that designates a range in which the posture of the workpiece is variable as a setting range of the gravity direction with respect to the workpiece, updates the gravity direction by a predetermined step angle within the specified setting range, and repeatedly executes the determination calculation; ,
Index data for evaluating the state of occurrence of the air puddle by expressing at least one of the number of air puddle occurrences, the number of elements and the size is calculated for each step angle, and the distribution of the index data is calculated for the occurrence of the air puddle. And an optimum posture calculating step of calculating an optimum posture of the workpiece from the step angle corresponding to the optimum region where the occurrence of air accumulation does not occur. Method. In the optimal posture calculation step,
The index data value in the optimal area is sequentially changed for each partial area corresponding to the step angle from the outer periphery side of the optimal area, and the step angle of the last partial area that retains the original value of the index data simulation method of an air reservoir of claim 1, wherein the calculating the optimum posture from. In the optimal posture calculation step,
Based on the index data, an objective function is created with the number of air pockets generated and the processing time of the discriminant calculation as design variables . Gravity until the objective function is minimized using the set range in the direction of gravity as a constraint. 2. The method of simulating an air pocket according to claim 1, wherein the direction angle is continuously updated, and the step angle when the objective function is minimized is calculated as the optimum posture of the workpiece. In the gravity direction update step,
The air pocket simulation method according to any one of claims 1 to 3 , wherein the step angle is set as an angle with respect to a coordinate axis of a coordinate system fixed to the workpiece. In the optimal posture calculation step,
Simulation method of an air reservoir according to any one of claims 1-4, characterized in that the processing visualize the occurrence of the air reservoir. Modeling the shape of the workpiece to be dipped with multiple element data, and executing discriminant calculation to determine whether the attribute of each element is gas or liquid based on the posture of the workpiece with respect to the direction of gravity In a simulation program for an air pool that can be executed by a computer that simulates the air pool,
A gravity direction updating step that designates a range in which the posture of the workpiece is variable as a setting range of the gravity direction with respect to the workpiece, updates the gravity direction by a predetermined step angle within the specified setting range, and repeatedly executes the determination calculation; ,
Index data for evaluating the state of occurrence of the air puddle by expressing at least one of the number of air puddle occurrences, the number of elements and the size is calculated for each step angle, and the distribution of the index data is calculated for the occurrence of the air puddle. And an optimum posture calculating step of calculating an optimum posture of the workpiece from the step angle corresponding to the optimum region where the occurrence of air accumulation does not occur. program. In the optimal posture calculation step,
The index data value in the optimal area is sequentially changed for each partial area corresponding to the step angle from the outer periphery side of the optimal area, and the step angle of the last partial area that retains the original value of the index data The air reservoir simulation program according to claim 6, wherein the optimum posture is calculated from the above. In the optimal posture calculation step,
Based on the index data, an objective function is created with the number of air pockets generated and the processing time of the discriminant calculation as design variables . Gravity until the objective function is minimized using the set range in the direction of gravity as a constraint. 7. The air reservoir simulation program according to claim 6, wherein the direction update is continued and the step angle when the objective function is minimized is calculated as the optimum posture of the workpiece. In the gravity direction update step,
The air pocket simulation program according to any one of claims 6 to 8 , wherein the step angle is set as an angle with respect to a coordinate axis of a coordinate system fixed to the workpiece. In the optimal posture calculation step,
The simulation program for an air reservoir according to any one of claims 6 to 9 , wherein the generation state of the air reservoir is visualized.

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