JP2018116560A - Structure analysis method, structure analyzer and structure analysis program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure analysis method capable of simply and properly setting particles on a surface to which external force is applied, and to provide a structure analyzer and a structure analysis program.SOLUTION: First virtual particles 35 are generated at a position separated from a free surface 33 of a cantilever beam 31 to the outside of the cantilever beam 31, specifically, at a position plane symmetrical with internal particles 32 arranged on the outermost layer on a free surface 33 side with respect to the free surface 33, and a boundary condition relative to external force is imparted to the first virtual particles 35. Then, the state of the internal particles 32 is calculated by using data of the internal particles 32 and the first virtual particles 35 to which the boundary condition is imparted.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a structure analysis method, a structure analysis apparatus, and a structure analysis program.

  The Finite Element Method (FEM) is widely applied to structural analysis and is known as a highly versatile analysis method. However, the finite element method requires a work to create a grid (mesh) in the analysis target area, and if the structure or the like is greatly deformed, it is difficult to continue the calculation because the grid collapses during the calculation. Have a problem.

  On the other hand, there is a particle method as one of analysis methods that have been attracting attention in recent years. Known particle methods include SPH (Smoothed Particle Hydrodynamics) and MPS (Moving Particle Simulation). In the particle method, an analysis object such as a structure is expressed as a collection of a plurality of particles, and the behavior of the analysis object is analyzed by calculating an interaction between these particles. Therefore, the particle method does not require the creation of a lattice performed by the finite element method (lattice method), and a model can be easily created in a short time even for a complex-shaped structure. Moreover, it is possible to cope with a large deformation of the free surface relatively easily.

Japanese Patent Laid-Open No. 2006-125934

  However, in the particle method analysis for structures, particle setting methods (particle creation (arrangement) method, boundary condition applying method) on the surface to which external force is applied have not been established. Depending on the case, the calculation accuracy may deteriorate.

  An object of the present invention is to provide a structure analysis method, a structure analysis apparatus, and a structure analysis program capable of easily and appropriately setting particles on a surface to which an external force is applied.

  In order to achieve the above object, a structural analysis method according to one aspect of the present invention is a structural analysis method based on a particle method that is executed by a computer and uses a structure as an analysis target. A modeling step for modeling as a group of the first, a first surface designation receiving step for accepting designation of the first surface to which an external force is applied among the outer surfaces to be analyzed, and an analysis from a position on the first surface or from the first surface A first virtual particle creating step for creating the first virtual particle at a position outside the target and at a first predetermined distance; an external force boundary condition applying step for applying a boundary condition related to external force to the first virtual particle; and the internal particle and the external force And calculating the state of the internal particles using the data of the first virtual particles to which the boundary condition is given.

  According to this configuration, the first virtual particle is created at a position on the first surface of the analysis target or a position away from the analysis target from the first surface, and a boundary condition related to external force is given to the first virtual particle. Is done. And the state of an internal particle is calculated using the data of the 1st virtual particle to which the internal particle and boundary conditions were provided.

  For example, in the method of giving boundary conditions related to external force to the internal particles arranged in the outermost layer on the first surface side, the state of the internal particles arranged inside the outermost layer is calculated, and the calculation result ( (Analysis result) may be deteriorated.

  On the other hand, in the method of providing the boundary condition regarding the external force to the first virtual particles, the calculation result can be obtained for the inner particles arranged in the outermost layer on the first surface side.

  Therefore, simple and appropriate setting of particles on the first surface to which an external force is applied is possible.

  Note that the present invention can be realized not only in the form of a structural analysis method but also in the form of a structural analysis apparatus including a computer and a program installed in the computer, for example.

  That is, a structural analysis device according to another aspect of the present invention includes a computer, and is a structural analysis device that performs a structural analysis by a particle method using a structure as an analysis target. Modeling processing for modeling as a collection of data, first surface designation acceptance processing for accepting designation of the first surface to which external force is applied, and analysis from a position on the first surface or from the first surface First virtual particle creation processing for creating first virtual particles at positions outside the target and at a predetermined distance, external force boundary condition application processing for applying boundary conditions related to external force to the first virtual particles, and boundaries related to internal particles and external force A calculation process for calculating the state of the internal particles is executed using the data of the first virtual particles to which the condition is given.

  A program according to still another aspect of the present invention is a program installed in a computer that performs a structure analysis by a particle method for analyzing a structure, and the analysis target is a collection of a plurality of internal particles. Modeling processing to model, first surface designation receiving processing for accepting designation of the first surface to which external force is applied among the outer surfaces to be analyzed, and the position of the analysis target from the position on the first surface or the first surface A first virtual particle creating process for creating the first virtual particle at a position apart from the outside by a predetermined distance; an external force boundary condition applying process for applying a boundary condition relating to the external force to the first virtual particle; and a boundary condition relating to the internal particle and the external force. A calculation process for calculating the state of the internal particles is executed using the data of the assigned first virtual particles.

  According to the present invention, it is possible to easily and appropriately set particles on a surface to which an external force is applied.

It is a block diagram which shows the electrical constitution of the structural analysis apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of the process performed by the analysis part of a structural analysis apparatus. It is a figure for demonstrating an example of the structure analysis method. It is a figure for demonstrating the other example of the structure-analysis method. It is a figure for demonstrating the other example of the production method of a virtual particle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Structure of structural analysis device>
A structural analysis apparatus 1 shown in FIG. 1 is an apparatus that analyzes a structure as an analysis target, models the analysis target as a collection of a plurality of internal particles, and performs a structural analysis by a particle method. The structural analysis apparatus 1 includes an input unit 11, an output unit 12, a storage unit 13, and an analysis unit 14.

  The input unit 11 is a device that receives input of various types of information. The input unit 11 is typically a keyboard, a mouse, or the like, but may be an external device that is connected so as to be able to communicate via a LAN (Local Area Network) or the like. In addition to data necessary for analysis, such as structure data to be analyzed and boundary conditions, the input unit 11 receives an instruction to start analysis.

  The output unit 12 is a device that outputs an analysis result. The output unit 12 is typically a display or a printer, but may be an external device connected so as to be able to communicate via a LAN or the like. For example, the output unit 12 displays (outputs) an analysis result (a calculation result after the analysis is completed) as an image.

  The storage unit 13 is a device that stores data, and is, for example, an HDD (hard disk drive) or a flash memory. The storage unit 13 stores a program for analysis, and stores data input to the input unit 11 and an analysis result when the analysis is executed.

  The analysis unit 14 includes, for example, a CPU and a RAM, and may include an ASIC (Application Specific Integrated Circuit). The analysis unit 14 includes a model particle creation unit 21, a virtual particle creation unit 22, a boundary condition application unit 23, and a state calculation unit 24 as function processing units for analysis. The model particle creation unit 21, the virtual particle creation unit 22, the boundary condition provision unit 23, and the state calculation unit 24 are realized by the CPU executing the program stored in the storage unit 13 using the RAM as a work area.

  Note that the configuration of the analysis unit 14 is not limited to the configuration illustrated in FIG. 1, and may be other configurations as long as the configuration described below can be executed.

  The model particle creation unit 21 models the structure as a collection of a plurality of internal particles from the shape data of the structure to be analyzed input to the input unit 11 and creates model data including position information of each internal particle. . When the model particle creation unit 21 creates model data, the model particle creation unit 21 stores the model data in the storage unit 13.

  The virtual particle creation unit 22 creates virtual particles outside the structure to be analyzed. Then, the virtual particle creation unit 22 stores virtual particle data including position information of each virtual particle in the storage unit 13.

  The boundary condition giving unit 23 gives a boundary condition to each virtual particle created by the virtual particle creating unit 22.

  The state calculation unit 24 calculates the state of each internal particle as a particle method algorithm using, for example, model data of each internal particle and data of each virtual particle to which boundary conditions are given based on SPH. Then, the state calculation unit 24 transmits the calculation result to the output unit 12, and the output unit 12 displays the calculation result as an image.

<Example of structural analysis method>
In the following, when a column-shaped cantilever 31 (an example of a structure, see FIG. 3) whose end surface on one side in the longitudinal direction is fixed to a fixed surface is to be analyzed, an external force is applied to the end surface on the other side An example of the structure analysis method will be described.

  When the structural analysis of the cantilever 31 is performed, the shape data of the cantilever 31 is input to the input unit 11 and the shape data is stored in the storage unit 13 before starting the analysis.

  When an instruction to start analysis is input to the input unit 11, the model particle creation unit 21 acquires the shape data stored in the storage unit 13 (S1 in FIG. 2).

  Thereafter, the model particle creation unit 21 models the cantilever 31 as a collection of a plurality of internal particles 32 as shown in FIG. Then, the model particle creation unit 21 creates model data including position information of each internal particle 32 (S2 in FIG. 2), and stores the model data in the storage unit 13.

  After creating the model data, the virtual particle creation unit 22 designates a free surface 33 (an example of the first surface) that is the free end of the cantilever 31 and a fixed surface 34 (an example of the second surface) that is the fixed end. It is determined whether or not an input is accepted by the input unit 11 (S3 in FIG. 2). Until the input of the designation of the free surface 33 and the fixed surface 34 is received by the input unit 11, the subsequent processing is not executed. The designation of the free surface 33 and the fixed surface 34 is performed by, for example, displaying a three-dimensional display based on the shape data stored in the storage unit 13 on a display device such as a display, and displaying it on the input unit 11 such as a mouse. It may be input by designating the surface of the shape displayed on the screen. In this way, by inputting the designation of the free surface 33 and the fixed surface 34, it is possible to easily designate the boundary condition in the particle method calculation.

  When the input of the designation of the free surface 33 and the fixed surface 34 is received by the input unit 11 (S3: YES in FIG. 2), the virtual particle creation unit 22 cantilever 31 as shown in FIG. 3B. The first virtual particles 35 and the second virtual particles 36 are created outside the surface. Specifically, the virtual particle creation unit 22 includes a first virtual particle creation unit 221 and a second virtual particle creation unit 222, as shown in FIG. As shown in FIG. 3 (b), the first virtual particle creation unit 221 has the first virtual particles in a plane symmetric position with respect to the internal particles 32 and the free surface 33 arranged in the outermost layer on the free surface 33 side. 35 is created (S4 in FIG. 2). The second virtual particle creation unit 222 creates the second virtual particle 36 at a position symmetrical with respect to the internal particle 32 and the fixed surface 34 arranged in the outermost layer on the fixed surface 34 side (S5 in FIG. 2).

  As shown in FIG. 1, the boundary condition applying unit 23 includes an external force boundary condition applying unit 231 and a fixed boundary condition applying unit 232. After the first virtual particle 35 and the second virtual particle 36 are created, the external force boundary condition applying unit 231 has a boundary condition (for external force) on the first virtual particle 35 as conceptually shown in FIG. (Load boundary condition) is assigned (S6 in FIG. 2). The fixed boundary condition providing unit 232 applies a boundary condition (displacement boundary condition) related to fixation to the second virtual particle 36 (S7 in FIG. 2).

  After the boundary condition is given, the state calculation unit 24 is given the model data of each internal particle 32, the data of each first virtual particle 35 to which the boundary condition related to external force is given, and the boundary condition related to fixation based on SPH. The state of each internal particle 32 is calculated using the data of each second virtual particle 36 (S8 in FIG. 2).

  When all calculations by the state calculation unit 24 are completed (S9 in FIG. 2: YES), an image corresponding to the calculation result is output to the output unit 12 as an analysis result (S10 in FIG. 2).

<Effect>
As described above, the position away from the free surface 33 of the cantilever 31 to the outside of the cantilever 31, specifically, the inner particles 32 and the free surface 33 arranged in the outermost layer on the free surface 33 side. Thus, the first virtual particle 35 is created at a plane-symmetrical position, and the boundary condition regarding the external force is given to the first virtual particle 35. Further, the position is separated from the fixed surface 34 of the cantilever 31 to the outside of the cantilever 31, specifically, the inner particles 32 arranged in the outermost layer on the fixed surface 34 side and the fixed surface 34 are plane-symmetric. The second virtual particle 36 is created at the position, and a boundary condition regarding fixation is given to the second virtual particle 36. And the state of the internal particle 32 is calculated using the data of the internal particle 32 and the 1st virtual particle 35 and the 2nd virtual particle 36 to which the boundary condition was provided.

  For example, in the method of imparting boundary conditions to the inner particles 32 arranged in the outermost layer on the free surface 33 side and the fixed surface 34 side, the inside of the inner particles 32 arranged inside the outermost layer is given the boundary condition. As for the particles 32, the movement of the particles is limited based on the boundary condition, so that the calculation result (analysis result) may be deteriorated.

  On the other hand, in the method of imparting boundary conditions to the first virtual particles 35 and the second virtual particles 36, the inner particles 32 arranged in the outermost layer on the free surface 33 side and the outermost layer on the fixed surface 34 side are arranged. Boundary conditions are not given to the internal particles 32, and a calculation result can be obtained.

  Therefore, the first virtual particle 35 and the second virtual particle 36 are created by designating the surface, and boundary conditions are given to the first virtual particle 35 and the second virtual particle 36, so that the free surface 33 and Simple and appropriate setting of the particles on the fixed surface 34 is possible. Therefore, structural analysis by the particle method can be performed without being a full-time analyst. Moreover, a good analysis result can be expected by simple and appropriate setting of particles on the free surface 33 and the fixed surface 34.

<Other examples of structural analysis methods>
In the example of the structural analysis method described above, the first virtual particle 35 and the second virtual particle 36 are created outside the cantilever 31 after the cantilever 31 is modeled as a collection of a plurality of internal particles 32. It was.

  Not limited to this, as shown in FIG. 4, after the first virtual particles 35 and the second virtual particles 36 are created outside the cantilever 31, the cantilever 31 is formed as a collection of a plurality of internal particles 32. It may be modeled.

  That is, in the structure analysis method shown in FIG. 4, after the input of the designation of the free surface 33 and the fixed surface 34 is received by the input unit 11, the first virtual particle creation unit 221 is shown in FIG. As described above, the first virtual particles 35 are created at positions where a first predetermined distance is opened outside the cantilever 31 with respect to the free surface 33. In addition, the second virtual particle creation unit 222 creates the second virtual particle 36 at a position where a second predetermined distance is opened outside the cantilever 31 with respect to the fixed surface 34.

  Thereafter, as shown in FIG. 4 (b), the model particle creation unit 21 has a surface target position with respect to the first virtual particle 35 and the free surface 33 and a surface with respect to the second virtual particle 36 and the fixed surface 34. An internal particle 32 is created at each target position.

  Then, as shown in FIG. 4C, the model particle creation unit 21 creates the remaining internal particles 32 with reference to the previously created internal particles 32.

  Also by this method, simple and appropriate setting of particles on the free surface 33 and the fixed surface 34 is possible. However, in the structure analysis method shown in FIG. 3, the internal particles 32 are created before the first virtual particles 35 and the second virtual particles 36 are created. There are few restrictions of the position of 32, and the cantilever 31 can be modeled easily.

<Other methods of creating virtual particles>
Further, as a method of creating the first virtual particles 35 and the second virtual particles 36, the method shown in FIG. 5 may be employed.

  That is, as shown in FIG. 5A, after the cantilever 31 is modeled as a collection of a plurality of internal particles 32 and the input of the designation of the free surface 33 and the fixed surface 34 is received by the input unit 11. The virtual particle creation unit 22 sets the offset surface 41 at a position where a predetermined distance is opened outside the cantilever 31 with respect to the outer surface of the cantilever 31 as shown in FIG. Then, the virtual particle creation unit 22 creates virtual particles 42 at the same interval as the interval between the internal particles 32 in a region sandwiched between the outer surface of the cantilever 31 and the offset surface 41.

  Thereafter, the virtual particle creation unit 22 leaves the virtual particles 42 created in the region sandwiched between the free surface 33 and the offset surface 41 as the first virtual particles 35, as shown in FIG. The virtual particles 42 created in the region sandwiched between the fixed surface 34 and the offset surface 41 are left as the second virtual particles 36, and the other virtual particles 42 are erased. Thereby, when the state of each internal particle 32 is calculated, there is no virtual particle 42 unnecessary for the calculation.

  Also by this method, simple and appropriate setting of particles on the free surface 33 and the fixed surface 34 is possible.

<Modification>
As mentioned above, although several embodiment of this invention was described, this invention can also be implemented with another form, and the above-mentioned structure has various in the range of the matter described in the claim. Design changes can be made.

1: Structural analysis device 14: Analysis unit 31: Cantilever 32: Internal particle 33: Free surface 34: Fixed surface 35: First virtual particle 36: Second virtual particle

Claims (7)

A structure analysis method executed by a computer and based on a particle method for analyzing a structure,
A modeling step of modeling the analysis object as a collection of a plurality of internal particles;
A first surface designation receiving step for receiving designation of a first surface to which an external force is applied among the outer surfaces to be analyzed;
A first virtual particle creating step of creating first virtual particles at a position on the first surface or a position away from the analysis target and a first predetermined distance from the first surface;
Applying an external force boundary condition to the first virtual particle with an external force boundary condition; and
And a calculation step of calculating a state of the internal particles using data of the first virtual particles to which boundary conditions related to the internal particles and the external force are given. The structural analysis method according to claim 1,
A second surface designation receiving step for accepting designation of a second surface different from the first surface among the outer surfaces to be analyzed;
A second virtual particle creating step of creating second virtual particles at a position on the second surface or on the second surface at a position outside the analysis target and a second predetermined distance;
A fixed boundary condition applying step for applying a boundary condition related to fixation to the second virtual particle,
In the calculation step, the state of the internal particle is determined using data of the first virtual particle to which the boundary condition related to the internal particle and the external force is applied and the second virtual particle to which the boundary condition related to the fixation is applied. The calculated structural analysis method. The structural analysis method according to claim 2,
The first virtual particle creation step and the second virtual particle creation step are executed after the modeling step,
In the first virtual particle creation step, the first virtual particles are created at positions symmetrical with respect to the internal particles and the first surface arranged in the outermost layer on the first surface side,
In the second virtual particle creation step, the second virtual particles are created at positions symmetrical with respect to the inner particles arranged in the outermost layer on the second surface side and the second surface. . The structural analysis method according to claim 2,
The first virtual particle creation step and the second virtual particle creation step are performed before the modeling step,
In the first virtual particle creation step, the first virtual particles are created outside the analysis target and on the first predetermined distance from the first surface,
In the second virtual particle creation step, the second virtual particles are created at a position outside the analysis target and on the second predetermined distance from the second surface,
In the modeling step, the internal particles are created at positions that are plane-symmetric with respect to the first virtual particle and the first surface and at positions that are plane-symmetric with respect to the second virtual particle and the second surface. And the remaining internal particles are created based on the created internal particles. A structural analysis method according to any one of claims 2 to 4, wherein
At least in the calculation step, a structural analysis method in which virtual particles do not exist outside the analysis target from the surfaces other than the first surface and the second surface among the outer surfaces of the analysis target. A structural analysis apparatus that includes a computer and performs structural analysis by a particle method for analyzing a structure,
The computer
Modeling processing for modeling the analysis object as a collection of a plurality of internal particles;
A first surface designation receiving process for receiving designation of a first surface to which an external force is applied among the outer surfaces to be analyzed;
A first virtual particle creation process for creating first virtual particles at a position on the first surface or a position away from the analysis target and a predetermined distance from the first surface;
An external force boundary condition applying process for applying a boundary condition related to external force to the first virtual particle;
A structural analysis apparatus that executes a calculation process for calculating a state of the internal particles using data of the first virtual particles to which boundary conditions related to the internal particles and the external force are given. A program installed in a computer that performs a structural analysis by a particle method for analyzing a structure,
In the computer,
Modeling processing for modeling the analysis object as a collection of a plurality of internal particles;
A first surface designation receiving process for receiving designation of a first surface to which an external force is applied among the outer surfaces to be analyzed;
A first virtual particle creation process for creating first virtual particles at a position on the first surface or a position away from the analysis target and a predetermined distance from the first surface;
An external force boundary condition applying process for applying a boundary condition related to external force to the first virtual particle;
A structural analysis program for executing a calculation process for calculating a state of the internal particles using data of the first virtual particles to which boundary conditions related to the internal particles and the external force are given.

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