JP5602326B1 - Ship design support program - Google Patents

Abstract

Provided is a technique capable of automatically specifying a closed section in a cross section of a ship in the process of designing the ship.
A ship design support program according to the present invention extracts a closed section candidate by bidirectionally tracing points and sides constituting an independent graph on a cross section of the ship, and a closed section candidate whose area is 0 or less. The closed section is specified by deleting.
[Selection] Figure 3

Description

  The present invention relates to a technique for supporting work for designing a ship.

  In the structure of the ship, there are a plurality of closed sections. In the ship design process, for example, when calculating structural strength, it is necessary to specify each closed section and use it for the calculation. However, ship structural data is described, for example, by a set of point coordinates and data that designates a side connecting the points, and it is difficult for a computer to automatically specify a closed section based on the structural data. Therefore, in the conventional ship design work, after the designer has empirically grasped the cross-sectional structure of the ship, various data relating to each closed section are provided to the calculation process by manual operation.

  The following Patent Document 1 discloses a technique for satisfying the requirements based on international regulations regarding the compartment structure of a ship.

WO2014 / 003055 Publication

  In order to design a ship that satisfies the requirements exemplified in Patent Document 1, a structural calculation for obtaining the strength of each part is required in the design process. However, when the closed section structure is designated by manual operation as described above, it is practically impossible or very difficult to calculate the structure in a plane having a complicated sectional structure such as an engine room.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of automatically specifying a closed section in a cross section of a ship in the process of designing the ship.

  The ship design support program according to the present invention extracts a closed block candidate by bidirectionally tracing points and sides constituting an independent graph on a cross section of the ship, and deletes the closed block candidate whose area is 0 or less. To identify the closed section.

  According to the ship design support program according to the present invention, even if the cross-sectional structure of the ship is complicated, it is possible to automatically specify the closed section without depending on the manual operation.

It is a figure which shows the computer 100 which performs the ship design assistance program 120 which concerns on Embodiment 1, and its periphery structure. It is a figure which shows the example of data of the structure data 131. It is a figure explaining the process in which the ship design assistance program 120 specifies the closed division candidate on the structure data 131. FIG. It is a figure explaining the method of deleting an extra candidate from closed section candidates. It is a flowchart explaining operation | movement of the ship design assistance program 120. FIG. It is a figure which shows the modification of the structure data. It is a flowchart of the process in which the ship design support program 120 extracts an independent graph from the structure data 131.

<Embodiment 1>
FIG. 1 is a diagram showing a computer 100 that executes a ship design support program 120 according to Embodiment 1 of the present invention and its peripheral configuration. The computer 100 includes a CPU (Central Processing Unit) 110, a ship design support program 120, and a storage device 130. The storage device 130 stores structure data 131.

  The ship design support program 120 is a program in which a process for supporting the work of designing the structure of the ship is implemented, and in particular, a process for automatically specifying a closed section existing on the cross section of the ship. The ship design support program 120 may be configured as an independent program module, or may be configured as a part of a program that implements other processes related to ship design. In the following, for the sake of simplicity of explanation, the processing for specifying the closed section will be mainly described.

  Hereinafter, for convenience of description, the ship design support program 120 may be described as an operation subject, but it is added that the CPU 110 actually executes the ship design support program 120.

  FIG. 2 is a diagram illustrating a data example of the structure data 131. The structure data 131 is data describing a structure in a cross section when a ship is cut vertically in the bow-stern direction, and is constituted by data designating coordinates of points of structures existing on the cross section and sides connecting the points. Has been.

  FIG. 2A shows a description example of the structure data 131. For the points, the XY coordinates of each point with an appropriate position as the origin and an ID for identifying each point are described. For the sides, IDs of points located at both ends of the side and IDs for identifying each side are described. FIG. 2B is an image diagram of the data example shown in FIG. FIG. 2B shows a cross-sectional structure (a hull transverse cross section) when the cross section of the ship is viewed from the top of the ship.

  FIG. 3 is a diagram illustrating a process in which the ship design support program 120 specifies a closed block candidate on the structure data 131. In the following, a procedure for specifying a closed segment candidate will be described with reference to FIG. The closed section candidate here is a set of points and sides that are candidates that can be regarded as closed sections in the cross-sectional structure described by the structure data 131.

  The ship design support program 120 follows a side in a certain direction with any point described in the structure data 131 as a start position. In FIG. 3, the origin of FIG. 2 is the initial start position. The fixed direction here may be any, but the direction once determined is not changed. In FIG. 3, it is directed leftward toward the drawing. Which direction the branch point proceeds can be determined by the positional relationship between the coordinates of each point.

  If the ship design support program 120 starts from the start position, traces the side, and returns to the start position, the ship design support program 120 extracts a section surrounded by the movement of one round as a closed section candidate. Here, the outermost rectangle shown in FIG. 3 is extracted.

  Similarly, the ship design support program 120 traces the sides in the same manner with other points described in the structure data 131 as starting positions. In principle, it is desirable to perform an edge search exhaustively with all points described in the structure data 131 as starting positions, but any of the points may be omitted as appropriate depending on the calculation load. FIG. 3 shows an example in which the side is traced leftward with the center point on the right side as the start position.

  When the above process is repeated, depending on the start position, the same side may be traced in two directions opposite to each other. In FIG. 3, the two sides indicated by the bold line at the bottom right follow in both directions. The ship design support program 120 regards such a side as having been searched and deletes it from the subsequent search target. If a point that is not connected to any side is generated by deleting the side, the point may be deleted from the search target.

  FIG. 4 is a diagram for explaining a method of deleting extra candidates from the closed section candidates. When the closed section candidates are extracted by the method described in FIG. 3, in addition to the three small sections shown in FIGS. 4A to 4C, as shown in FIG. Large parcels are also extracted. That is, in FIG. 3, there are four closed section candidates.

  However, as is apparent from the visual sense, the cross-sectional structure shown in FIG. 3 is composed of three closed sections, and regarding this as four closed sections leads to an erroneous calculation result in a process such as structural calculation. Therefore, the ship design support program 120 deletes extra closed section candidates by the following method.

  The ship design support program 120 first obtains the area of each closed section candidate from the cross-sectional zero-order moment. In consideration of the direction in which the side is traced in FIG. 3, the inner area of each small section shown in FIGS. 4A to 4C is obtained. On the other hand, for the large section shown in FIG. 4 (d), when considering the direction in which the side is traced in FIG. In this manner, by deleting a closed block candidate whose cross-sectional zero-order moment has a negative value, a correct closed block candidate can be extracted.

  FIG. 5 is a flowchart for explaining the operation of the ship design support program 120. Hereinafter, each step of FIG. 5 will be described.

(FIG. 5: Step S501)
The ship design support program 120 reads the structure data 131 from the storage device 130 and creates a list of non-overlapping edges according to the description of the structure data 131. The term “side overlap” means that, for example, the side from the origin to the lower left point and the side from the lower left point to the origin in FIG. 2B are regarded as two different sides. Searching for the same side in duplicate is inefficient in processing efficiency, so such side overlap is eliminated in advance by this step.

(FIG. 5: Step S502)
The ship design support program 120 comprehensively performs the following steps S503 to S505 for each side included in the side list created in step S502.

(FIG. 5: Steps S503 to S505)
The ship design support program 120 extracts an appropriate side (and its end point) in the side list (S503), and traces the point and the side in a predetermined direction (left direction in FIG. 3) by the method described in FIG. At the same time, the direction traced for each side is stored (S504). When there is an edge traced in both directions, the ship design support program 120 deletes the edge from the edge list at that time (S505). The ship design support program 120 extracts a region surrounded by the route as a closed section candidate for the route that can return to the start position in these steps.

(FIG. 5: Steps S506 to S507)
The ship design support program 120 calculates the area of each closed section candidate extracted in steps S502 to S505 as a cross-sectional zero-order moment. Closed section candidates whose area is 0 or less are deleted. The ship design support program 120 outputs data describing a list of points and sides constituting the closed section candidate to an appropriate output destination such as the storage device 130, for example.

<Embodiment 1: Summary>
As described above, when the ship design support program 120 according to the first embodiment can return to the original start position by following the points described in the structure data 131 in a certain direction, the ship design support program 120 is surrounded by the route. Are extracted as closed section candidates. Edges traced in both directions are deleted from the search target. If the zero-order moment of the cross section candidate is 0 or less, the closed section candidate is deleted. By the above method, the points and sides described in the structure data 131 can be automatically and efficiently searched to extract closed section candidates, and candidates that are not suitable for being regarded as closed sections can be removed.

<Embodiment 2>
FIG. 6 is a diagram illustrating a modified example of the structure data 131. The structure data 131 may include points and sides that do not constitute a closed section to be detected, as indicated by “beard” in FIG. 6. In the second embodiment of the present invention, a method in which the ship design support program 120 deletes such points and lines in advance will be described. Other configurations are the same as those of the first embodiment.

  The ship design support program 120 identifies a point that is connected to only one of the points described in the structure data 131 between steps S501 and S502 in FIG. It deletes from the search object after S502. In FIG. 6, the point of coordinates (−150, 100) corresponds to this. The ship design support program 120 further deletes the side connected to the point from the search targets after step S502.

  The ship design support program 120 repeats the same processing. As a result, the coordinates (−100, 100) shown in FIG. 6 and the points connected thereto are also deleted from the search targets after step S502. As a result, the same list of points and sides as in FIG. 2B remains, so that the search efficiency can be maintained as in the first embodiment.

  The ship design support program 120 may sort the point list in advance in ascending order of the number of connected sides before performing the above processing. In this case, since only one connected edge is gathered near the top of the sorted list, the above process can be completed at high speed. If the sort order is maintained even after the points and sides constituting the beard are deleted, it is convenient from the viewpoint of simple processing because it is always necessary to check only the vicinity of the head of the sorted list.

<Embodiment 3>
The first and second embodiments have been described on the assumption that the structure data 131 describes a cross-sectional structure forming a single independent graph (a graph not connected to other graphs). That is, there is only one graph composed of a set of points and edges. However, the actual cross-sectional structure of a ship may include a plurality of independent graphs. Therefore, the ship design support program 120 according to the third embodiment of the present invention extracts an independent graph from the structure data 131 before the processing described in the first and second embodiments. Others are the same as in the first and second embodiments.

  FIG. 7 is a flowchart of processing in which the ship design support program 120 extracts an independent graph from the structure data 131. Hereinafter, each step of FIG. 7 will be described.

(FIG. 7: Step S701)
The ship design support program 120 creates an adjacency matrix M from a list of sides described by the structure data 131. The adjacency matrix M is a matrix in which elements M (i, j) and M (j, i) are both 1 when there is an edge connecting point i and point j.

(FIG. 7: Step S702)
The ship design support program 120 sequentially multiplies the adjacency matrix M with respect to the points i = 1,... N (total number of points) to obtain M ^N. Since the adjacency matrix M is a matrix in which the element corresponding to the edge between the connected points is 1, the element corresponding to the connected edge becomes 1 or more as this is multiplied for each point. Yes, other elements are converged to a matrix of zero.

(FIG. 7: Step S703)
The ship design support program 120 extracts the graph by specifying the connection relation between the points according to the matrix ^MN obtained in step S702. Furthermore, an independent graph can be extracted by specifying a graph that is not connected to another graph.

(FIG. 7: Step S703: Supplement)
The diagram on the right side of FIG. 7 is an image diagram of the independent graph represented by the matrix ^MN . The element of the row i of the matrix ^MN has an element value of 1 or more for a point connected to the point i, and an element value of 0 for a point not connected to the point i. Since the adjacency matrix M is a symmetric matrix, the column i has the same value. Therefore, when the element values constituting the independent graph are gathered by arranging the matrix ^MN , the portions corresponding to the independent graphs appear as one lump as shown in the right diagram of FIG. However, since the right diagram in FIG. 7 allows each independent graph represented by the matrix ^MN to be visually grasped, it is necessary for the ship design support program 120 itself to perform the alignment as shown in the right diagram in FIG. Absent.

  The ship design support program 120 identifies each independent graph described in the structure data 131, identifies a closed section using the method described in the first and second embodiments for each independent graph, and outputs the result. Output.

<Embodiment 4>
In the first to third embodiments, the method for specifying the closed section included in one or more independent graphs included in the cross-sectional structure of the ship has been described. Although this method would normally yield correct results, it is desirable to verify that the obtained results are geometrically correct. Therefore, the ship design support program 120 according to Embodiment 4 of the present invention checks that the identification result of the closed section is appropriate by the method described below after implementing the methods of Embodiments 1 to 3. Other configurations are the same as those in the first to third embodiments.

  Euler's polyhedron theorem is expressed as (number of vertices) − (number of sides) + (number of polygons) = 1 when a planar polygon is divided into one or more polygons by a set of line segments. As described in the third embodiment, when there are a plurality of independent graphs, the same formula is established by replacing the right side of the formula with the number of independent graphs.

  The ship design support program 120 can verify the validity by checking whether or not the number of closed sections obtained by implementing the methods of the first to third embodiments satisfies the above formula. If the number of closed sections does not satisfy the above formula, a warning that an algorithm error has occurred is output, for example. In this case, the operator continues the calculation using, for example, a conventional closed section specifying process by manual operation in a complementary manner.

  100: Computer, 110: CPU, 120: Ship design support program, 130: Storage unit, 131: Structure data.

Claims (5)

A ship design support program for causing a computer to execute a process for supporting design of a ship structure, wherein the computer
Reading from the storage device structure data describing information specifying the coordinates of the points representing the cross-sectional structure of the ship and the sides connecting the points;
A closed section enumeration step for identifying a closed section candidate in the cross section of the ship by tracing any one of the points in the cross section of the ship as a start position and following the side in a certain direction and returning to the start position.
A direction storage step of storing the point and the side traced in the process of executing the closed section enumeration step together with the traced direction;
Executing the closed section enumeration step and the direction storage step with each point in the cross section of the ship as the start position,
Deleting the sides traced along two opposite directions in the closed section enumerating step and the direction storing step;
Determining the area of each of the closed section candidates by determining the cross-sectional zero-order moment of each of the closed section candidates, and deleting the closed section candidate having an area of 0 or less;
Outputting the list of the points and the sides constituting the closed section candidate as data for specifying the closed section in the cross section of the ship;
A ship design support program characterized by causing The ship design support program, in the computer, before the closed section enumeration step, the point that is connected to only one side, and the extra point that deletes the side connected to the point. The ship design support program according to claim 1, wherein a deletion step is executed. The ship design support program, in the redundant point deletion step, to the computer,
Sorting the points described by the structure data in ascending order of the connected edges;
In order from the top of the list of points obtained by the sorting, the point that is connected to only one side, and the side connected to the point are deleted,
The ship design support program according to claim 2, wherein: The ship design support program causes the computer to identify one or more independent graphs constituted by the points and the edges before the closed section enumeration step, and for each of the identified independent graphs, The ship design support program according to any one of claims 1 to 3, wherein a step is executed. The ship design support program, after the step of deleting the closed section candidate in the computer,
Checking whether the closed block candidate is valid based on Euler's polyhedron theorem,
Issuing a warning that an error has occurred if the closed block candidate is not valid;
The ship design support program according to any one of claims 1 to 4, wherein the ship design support program is executed.

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