JP4364133B2 - Local coordinate system determination program - Google Patents

Description

  The present invention relates to a local coordinate system determination program, and more particularly to a local coordinate system determination program for determining a local coordinate system different from a reference coordinate system.

  The structural analysis performs structural strength analysis, vibration analysis, impact / drop analysis, and the like. For example, in the strength analysis of a structure, it is possible to calculate deformation (strain) and stress generated inside when a load is applied to a place where the structure is located. In structural analysis, the finite element method is mainly used.

Conventionally, in order to analyze a frame structure (ramen structure) with structural analysis software using the finite element method, it is necessary to determine a local coordinate system (element coordinate system or member coordinate system, etc.) different from the reference coordinate system. was there. Patent Document 1 discloses the contents for determining a local coordinate system for each part.
JP-A-9-81775

  In the operation of determining the local coordinate system, the user defines a vector for the structure to be analyzed. Since the definition of the vector can be performed in various ways (infinite), there is a problem that it is very difficult to understand and complicated. Until now, there is no tool for automatically determining the local coordinate system. Therefore, conventional structural analysis software and the like have a problem that the structural analysis cannot be easily performed because the operation of determining the local coordinate system is difficult.

  The present invention has been made in view of the above points, and an object thereof is to provide a local coordinate system determination program that can automatically and easily determine a local coordinate system different from the reference coordinate system.

In order to solve the above-described problem, the present invention provides a computer with a first step of receiving a definition of a geometric shape connecting edges that are central axes of members to be analyzed from a user, and circumscribing the received geometric shape. A second step of defining a rectangular parallelepiped, and a step of projecting the edge and the central point of the rectangular parallelepiped onto a projection surface of the rectangular parallelepiped based on an axis of a reference coordinate system of the rectangular parallelepiped, and calculating a projection edge and a projection central point A third step, a fourth step of determining, for each edge , one axis of a local coordinate system different from the reference coordinate system based on the calculated projection edge and the projection center point, and the determined local coordinates based on the first axis of the system, and a fifth step of determining the two axes of the local coordinate system, based on the first axis and two axes of the local coordinate system with the determined, the three axes of the local coordinate system decision to Characterized in that it is a local coordinate system determining program for executing the sixth step.

In the local coordinate system determination program of the present invention, a local coordinate system different from the reference coordinate system can be automatically and easily determined for each edge . For example, if the present invention is applied to structural analysis software, etc., the operation of determining the local coordinate system becomes automatic and simple. Therefore, even a general designer who performs the structural analysis for the first time can easily perform the structural analysis. Can do.

  As described above, according to the present invention, it is possible to provide a local coordinate system determination program that can automatically and easily determine a local coordinate system different from the reference coordinate system.

  Next, the best mode for carrying out the present invention will be described based on the following embodiments with reference to the drawings. First, an example of a computer system that executes the local coordinate system determination program of the present invention will be described.

  FIG. 1 is a hardware configuration diagram of an example of a computer system. The computer system is configured to include an input device 11, an output device 12, a drive device 13, an auxiliary storage device 14, a memory device 15, an arithmetic processing device 16, and an interface device 17 that are mutually connected by a bus B. . Various devices constituting the computer system may be housed in a single housing or may be housed in a plurality of housings.

  The input device 11 includes a keyboard, a mouse, and the like, and is used for inputting various operation instructions. The output device 12 includes a display and displays various windows and data necessary for operation. The interface device 17 is an interface for connecting to other devices, systems, networks, and the like.

  The local coordinate system determination program is provided by a recording medium 18 such as a CD-ROM. The recording medium 18 is set in the drive device 13. The local coordinate system determination program is installed in the auxiliary storage device 14 from the recording medium 18 via the drive device 13. The recording medium 18 is a recording medium that records information optically, electrically, or magnetically such as a CD-ROM, flexible disk, magneto-optical disk (MO), or information such as a ROM or flash memory. It is possible to use various types of recording media such as a semiconductor memory that electrically records data.

  The local coordinate system determination program includes a program recorded on a recording medium of another computer connected via a network (not shown). The local coordinate system determination program recorded in a recording medium of another computer is downloaded via the network and installed in the auxiliary storage device 14. The auxiliary storage device 14 stores the installed local coordinate system determination program and various files necessary for the processing of the local coordinate system determination program.

  The memory device 15 reads and stores the local coordinate system determination program from the auxiliary storage device 14. The arithmetic processing unit 16 controls various devices of the computer system according to a local coordinate system determination program stored in the memory device 15. Hereinafter, the processing of the local coordinate system determination program of the present invention will be described sequentially.

  In order to analyze the frame structure with structural analysis software using the finite element method, it is necessary to determine a local coordinate system different from the reference coordinate system. The local coordinate system determination program of the present invention automatically and easily determines a local coordinate system. Here, the local coordinate system is a coordinate system for determining the direction in which the member is arranged, and refers to a member coordinate system such as an element coordinate system in the finite element method.

FIG. 2 is a flowchart showing the processing of the local coordinate system determination program. Step S
Proceeding to 1, the arithmetic processing unit 16 defines the geometric shape of the structure to be analyzed as will be described later. In step S2, the arithmetic processing unit 16 performs automatic determination of one axis of the local coordinate system as described later. In step S3, the arithmetic processing unit 16 performs automatic determination of the 2-axis and 3-axis of the local coordinate system as described later.

  FIG. 3 is a flowchart showing processing for defining a geometric shape. In step S11, the user defines the structure to be analyzed as shown in FIG. 4 using a wire frame model (a model in which the central axes of the members are connected by lines) using CAD or the like. FIG. 4 is an image diagram of an example of a wire frame model.

  In step S12, the arithmetic processing unit 16 defines a rectangular parallelepiped (orthogonal space) A as shown in FIG. 5 that circumscribes the defined wire frame model. The rectangular parallelepiped A has a reference coordinate system as shown in FIG. Further, the rectangular parallelepiped A has a center at a point a, and each surface is defined as an X0 plane, an X1 plane, a Y0 plane, a Y1 plane, a Z0 plane, and a Z1 plane.

  FIG. 6 is a flowchart showing processing for determining one axis of the local coordinate system. FIG. 7 is an image diagram showing processing for determining one axis of the local coordinate system. Proceeding to step S21, the arithmetic processing unit 16 prioritizes the axes of the reference coordinate system for projecting the edges.

  For example, the projection of the edge is performed in three types, the X-axis direction, the Y-axis direction, and the Z-axis direction. The surfaces on which the edges are projected are two surfaces in the X-axis direction, the Y-axis direction, and the Z-axis direction (for example, the X0 surface and the X1 surface in the case of the X-axis direction). The arithmetic processing unit 16 prioritizes the projection direction in the order of the largest number of edges that can be projected.

  Specifically, the total number of edges constituting the wire frame model is 100, the number of edges that can be projected in the X-axis direction is 95 (50 on the X0 plane, 45 on the X1 plane), and the number of edges that can be projected in the Y-axis direction is 90 (40 on the Y0 plane, 45 on the Y1 plane), and the number of edges that can be projected in the Z-axis direction is 93 (43 on the Z0 plane and 50 on the Z1 plane), the priority in the projection direction is the X-axis and the Z-axis. , Y-axis order.

  In addition, it is possible to prioritize the axes of the reference coordinate system for projecting edges by various methods, such as the longest side of the rectangular parallelepiped A, the shortest order, the order of the X-axis, Y-axis, and Z-axis of the reference coordinate system. it can.

  Proceeding to step S22, the arithmetic processing unit 16 projects the edge and point a as shown in FIG. 7A onto the surface of the rectangular parallelepiped A as shown in FIG. 7B. In the following description, an edge on a plane (projection plane) projected onto the plane of the rectangular parallelepiped A is called a projection edge, and a point a ′ on the projection plane is called a projection center point.

  Here, the projection direction is determined to be the axial direction of the reference coordinate system that is not parallel to the edge (or the angle formed is equal to or greater than a predetermined value), and is determined based on the prioritization of the axes of the reference coordinate system performed in step S21. . For example, when projecting in the X-axis direction, there are two projection planes, the X0 plane and the X1 plane, but the edge is projected on the plane closer to the edge (the center point thereof). That is, the projection plane changes depending on the position of the edge in the rectangular parallelepiped A. In FIG. 7, the X-axis direction of the reference coordinate system is determined as the projection direction. Further, the X1 plane of the rectangular parallelepiped A is determined as the projection plane.

  Proceeding to step S23, as shown in FIG. 7C, the arithmetic processing unit 16 sees the projection plane from the point a which is the center of the rectangular parallelepiped A, and rotates clockwise (or counterclockwise with respect to the point a ′ on the projection plane. Orient the projection edge so that it is clockwise. Proceeding to step S24, as shown in FIG. 7D, the arithmetic processing unit 16 sets the original edge direction (vector) corresponding to the projection edge direction attached in step S23 to 1 in the local coordinate system of the edge. Determine as axis. Note that the origin of one axis in the local coordinate system is the end point of the edge.

  The process shown in the flowchart of FIG. 6 is performed for each edge constituting the wire frame model. The arithmetic processing unit 16 can automatically determine one axis of the local coordinate system of each edge constituting the wire frame model by the process shown in the flowchart of FIG.

  FIG. 8 is a flowchart showing processing for determining the second and third axes of the local coordinate system. FIG. 9 is an image diagram showing processing for determining two axes in the local coordinate system. Proceeding to step S31, as shown in FIG. 9A, the arithmetic processing unit 16 changes from the projection edge start point (a point corresponding to the origin of one axis of the local coordinate system) to the point a ′ which is the projection center point. The going vector (or the reverse vector) is determined as the direction vector of the V vector. The direction vector of the V vector is a vector in the projection plane.

  Proceeding to step S32, the arithmetic processing unit 16 determines the two axes of the local coordinate system of each edge from the direction vector of the V vector, as shown in FIG. 9B. Specifically, the arithmetic processing unit 16 determines the two axes of the local coordinate system of each edge by matching the origin of the direction vector of the V vector with the origin of one axis of the local coordinate system. The V vector is an in-plane vector including one axis and two axes of the local coordinate system. Proceeding to step S33, the arithmetic processing unit 16 determines three axes of the local coordinate system of each edge from one axis and two axes of the local coordinate system using, for example, the right-hand system representing the positional relationship of the axes.

  The processing shown in the flowchart of FIG. 8 is performed for each edge constituting the wire frame model. The arithmetic processing unit 16 can automatically determine the two and three axes of the local coordinate system of each edge constituting the wire frame model by the process shown in the flowchart of FIG. As described above, according to the local coordinate system determination program of the present invention, the local coordinate system can be determined automatically and easily.

  FIG. 10 is a flowchart showing the processing of the local coordinate system determination program. Proceeding to step S100, the arithmetic processing unit 16 defines a structure to be analyzed by a wire frame model as in step S1 described above. In step S101, the arithmetic processing unit 16 performs automatic determination of one axis of the local coordinate system in the same manner as in step S2 described above.

  In addition to the above-described step S2, the process of step S101 includes a vector from the end point close to (or far from) the center a of the rectangular parallelepiped A to the end point far from (or close to) the local coordinate system. It is good also as one axis. Further, the processing of step S101 may determine the direction of the edge in the axial direction of the reference coordinate system having the smallest angle with the edge, and use the edge direction vector as one axis of the local coordinate system. Further, the processing in step S101 may use a vector from the start point of the edge to the end point as one axis of the local coordinate system. For example, the start point and end point of an edge can be determined according to the start point and end point when a line is drawn using CAD or the like.

  Proceeding to step S102, the arithmetic processing unit 16 accepts from the user one axis correction of the local coordinate system determined for each edge in step S101. For example, the arithmetic processing unit 16 displays the orientation of one axis of the local coordinate system determined for each edge in step S101 on the output device 12 by using a symbol or the like together with the edge. The user operates the input device 11 to select an edge that needs to be corrected (inversion of the direction of one axis of the local coordinate system), and instructs to invert the direction of the one axis of the local coordinate system of the edge. The arithmetic processing unit 16 reverses the direction of one axis of the local coordinate system of the edge in accordance with an instruction from the user.

  Proceeding to step S103, the arithmetic processing unit 16 performs automatic determination of the two axes and three axes of the local coordinate system in the same manner as step S3 described above. In addition to the above-described step S3, the processing in step S103 is performed by using a vector (or a vector in the opposite direction) from the starting point (origin) of one axis of the local coordinate system to the point a for each edge as a V vector. Two axes of the local coordinate system may be determined. Further, the process of step S103 may determine two axes of the local coordinate system with the reference vector having the maximum angle formed with one axis of the local coordinate system among the reference vectors of the reference coordinate system for each edge as the V vector direction. Good. Then, the arithmetic processing unit 16 determines three axes of the local coordinate system of each edge from one axis and two axes of the local coordinate system by the right hand system described above.

  Proceeding to step S104, the arithmetic processing unit 16 receives from the user the correction of the 2-axis and 3-axis of the local coordinate system determined for each edge in step S103. For example, the arithmetic processing unit 16 displays the orientations of the two and three axes of the local coordinate system determined for each edge in step S103 on the output device 12 with symbols and the like together with the edges (or one axis of the local coordinate system). Instead of displaying the local coordinate system, the actual cross-sectional shape of the member may be displayed.

  The user operates the input device 11 to select an edge that needs to be corrected (rotation of two or three axes in the local coordinate system), and the orientation of the two or three axes in the local coordinate system of the edge is shown in FIG. As shown, the rotation angle is specified in the 2-3 axis plane of the local coordinate system to instruct the rotation. FIG. 11 is an image diagram of an example showing correction of two axes and three axes of the local coordinate system. The arithmetic processing unit 16 rotates the directions of the two and three axes of the edge local coordinate system in accordance with an instruction from the user.

  Proceeding to step S105, the arithmetic processing unit 16 receives from the user the final correction of the first to third axes of the local coordinate system determined for each edge. For example, the arithmetic processing unit 16 displays the directions of the 1st to 3rd axes of the local coordinate system determined for each edge on the output device 12 together with the edge with a symbol or the like. In addition, you may make it display the shape of an actual member instead of displaying a local coordinate system.

  The user operates the input device 11 to select an edge that needs to be corrected. The user can change the local coordinate system of the selected edge by an operation such as clicking the mouse as follows, for example. First, by the first to third operations, the arithmetic processing unit 16 rotates the local coordinate system of the selected edge 90 degrees (clockwise or counterclockwise) in the 2-3 axis plane. Subsequently, by the fourth operation, the arithmetic processing unit 16 reverses the direction of one axis of the local coordinate system. Further, by the fifth to seventh operations, the arithmetic processing unit 16 rotates the local coordinate system of the selected edge by 90 degrees (clockwise or counterclockwise) in the 2-3 axis plane.

  If the 1st to 3rd axes of the local coordinate system are finally corrected in such a procedure, the local coordinate system can be changed to the intended direction by the seventh operation at the maximum. In the case of the finite element method, the element coordinate system of each element is determined with the starting point (first node) of each element after element division as the origin.

  In step S105, as yet another method, the arithmetic processing unit 16 independently performs the reversing operation of the direction of one axis of the local coordinate system and the rotating operation in the 2-3 axis plane of the local coordinate system in any order. And the final correction of the first to third axes of the local coordinate system may be performed.

  The arithmetic processing unit 16 automatically determines 1 to 3 axes of the local coordinate system of each edge constituting the wire frame model by the process shown in the flowchart of FIG. 10, and then requires 1 to 3 axes of the local coordinate system. Can be modified according to Note that the processes of steps S102, S104, and S105 in the flowchart of FIG. 10 can be omitted as appropriate. As described above, according to the local coordinate system determination program of the present invention, the local coordinate system can be determined automatically and easily.

  The local coordinate system determination program shown in the first and second embodiments can be applied to a solid model creation method by CAD of a frame structure. The local coordinate system determination program of the present invention can be applied to, for example, a solid model creation program or a design support (CAD) program.

  FIG. 12 is a flowchart illustrating an example of the procedure of the solid model creation method. In step S200, the arithmetic processing unit 16 creates a wire frame model on the neutral axis of the frame structure based on an instruction from the user. In step S201, the arithmetic processing unit 16 defines the local coordinate system of each edge (member) constituting the wire frame model by the processing of the local coordinate system determination program of the present invention described in the first or second embodiment. Do. In step S202, the arithmetic processing unit 16 defines the cross-sectional shape of the edge (member) based on an instruction from the user.

  In step S203, the arithmetic processing unit 16 arranges (deploys) the cross-sectional shape defined in step S202 in the wire frame model, and creates a solid model. The arithmetic processing unit 16 can apply the local coordinate system determination program shown in the first and second embodiments to the solid model creation method by CAD of the frame structure by the processing shown in the flowchart of FIG. Therefore, the local coordinate system can be automatically and easily determined in the solid model creation program and the design support program.

The present invention may have the following configurations as described below.
(Appendix 1)
On the computer,
A first procedure for recognizing one or more elements constituting a geometric shape and determining one axis of a local coordinate system different from the reference coordinate system for each element;
A second procedure for determining two axes of the local coordinate system according to one axis of the local coordinate system;
A local coordinate system determination program for executing a third procedure for determining three axes of the local coordinate system according to one axis and two axes of the local coordinate system.
(Appendix 2)
The first step is a step of projecting the element and the center point of the rectangular parallelepiped as a projection element and a projection center point on a plane of the rectangular parallelepiped that takes the reference coordinate system circumscribing the geometric shape;
Directing the projection element so that the projection surface on which the projection element and the projection center point are projected is clockwise or counterclockwise with respect to the projection center point when viewed from the center point of the rectangular parallelepiped;
The local coordinate system determination program according to claim 1, further comprising a procedure for determining for each element the direction of the element corresponding to the direction of the projection element as one axis of the local coordinate system.
(Appendix 3)
The second step is a step of determining a vector from the start point of the projection element toward the projection center point as a direction vector;
The local coordinate system determination program according to supplementary note 2, comprising: a procedure for determining each element by using the direction vector and the direction corresponding to the start point of the element as two axes of the local coordinate system.
(Appendix 4)
The supplementary notes 1 to 3, wherein the third procedure determines three axes of the local coordinate system from one axis and two axes of the local coordinate system using a right-handed system or a left-handed system. The local coordinate system determination program described.
(Appendix 5)
After the first to third steps, 1 to 3 axes of the determined local coordinate system are visually displayed, and when there is a correction request from the user, the local coordinate system is changed according to the correction request. The local coordinate system determination program according to any one of appendices 1 to 4, further comprising a procedure of correcting one to three axes.
(Appendix 6)
On the computer,
A first procedure for recognizing one or more elements constituting a geometric shape and determining one axis of a local coordinate system different from the reference coordinate system for each element;
A second procedure for determining two axes of the local coordinate system according to one axis of the local coordinate system;
A structure analysis program for executing a third procedure for determining three axes of the local coordinate system according to one axis and two axes of the local coordinate system.
(Appendix 7)
On the computer,
A first procedure for recognizing one or more elements constituting a geometric shape and determining one axis of a local coordinate system different from the reference coordinate system for each element;
A second procedure for determining two axes of the local coordinate system according to one axis of the local coordinate system;
A solid model creation program for executing a third procedure for determining three axes of the local coordinate system according to one axis and two axes of the local coordinate system.
(Appendix 8)
On the computer,
A first procedure for recognizing one or more elements constituting a geometric shape and determining one axis of a local coordinate system different from the reference coordinate system for each element;
A second procedure for determining two axes of the local coordinate system according to one axis of the local coordinate system;
A design support program for executing a third procedure for determining three axes of the local coordinate system according to one axis and two axes of the local coordinate system.

  The present invention is not limited to the specifically disclosed embodiments, and various modifications and changes can be made without departing from the scope of the claims.

It is a hardware block diagram of an example of a computer system. It is a flowchart showing the process of the local coordinate system determination program. It is a flowchart showing the process which defines a geometric shape. It is an image figure of an example of a wire frame model. It is an image figure of the rectangular parallelepiped which circumscribes a wire frame model. It is a flowchart showing the process which determines 1 axis | shaft of a local coordinate system. It is an image figure showing the process which determines 1 axis | shaft of a local coordinate system. It is a flowchart showing the process which determines the 2nd, 3rd axis | shaft of a local coordinate system. It is an image figure showing the process which determines 2 axes | shafts of a local coordinate system. It is a flowchart showing the process of the local coordinate system determination program. It is an image figure of an example showing 2 axis | shaft and 3 axis | shaft correction of a local coordinate system. It is an example flowchart showing the procedure of the solid model creation method.

Explanation of symbols

11 Input Device 12 Output Device 13 Drive Device 14 Auxiliary Storage Device 15 Memory Device 16 Arithmetic Processing Device 17 Interface Device 18 Recording Medium

Claims (4)

On the computer,
A first step of receiving a definition of a geometric shape connecting edges that are central axes of members to be analyzed from a user;
A second step of defining a cuboid circumscribing the accepted geometry;
A third step of projecting the edge and the center point of the rectangular parallelepiped on the projection surface of the rectangular parallelepiped based on the axis of the reference coordinate system of the rectangular parallelepiped, and calculating the projection edge and the projection center point;
A fourth step of determining, for each edge , one axis of a local coordinate system different from the reference coordinate system based on the calculated projection edge and the projection center point ;
Based on said one axis of the local coordinate system with the determined, a fifth step of determining the two axes of the local coordinate system,
Based on the first axis and two axes of the local coordinate system the determined local coordinate system determining program for executing a sixth step of determining the 3-axis of the local coordinate system. The fourth step includes
Before the projection plane Kito shadow edge and the projection center point is projected, the step of calculating the orientation of the projection edge so that the clockwise or counterclockwise direction with respect to the previous SL projection center point,
Determining for each edge direction of the edge corresponding to the orientation of the projection edge and said operation as one axis of the local coordinate system
The Yusuke claim 1 local coordinate system determining program, wherein Rukoto. The fifth step includes
A step of computing the power sale way direction vector suited to the projection center point from the start point of the projection edge,
A step of based on said computed direction vector and the previous KiHajime point, to determine the two axes of the local coordinate system for each of the edges
The Yusuke claim 1 local coordinate system determining program, wherein Rukoto. The local coordinate system determination program according to claim 1, further comprising:
In the computer,
Defining a cross-sectional shape of the edge based on instructions received from the user;
Arranging a cross-sectional shape for each of the edges constituting the geometric shape based on the determined local coordinate system and the defined cross-sectional shape
A local coordinate system determination program characterized in that

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