KR101682379B1 - Method for three dimensions pressure interpolation technology, and recording medium storing program for executing the same, and recording medium storing program for executing the same - Google Patents

Abstract

The present invention relates to a three-dimensional pressure mapping method, a recording medium storing a program for implementing the same, and a computer program stored in a medium for implementing the same. More specifically, the present invention relates to a three- Dimensional pressure mapping method applicable to uniform or nonuniform surface pressure mapping problems by applying the surface pressure calculation method and the pressure equivalent node load conversion method of the present invention, a recording medium storing a program for implementing the same, And provides a stored computer program.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional pressure mapping method, a recording medium storing a program for implementing the same, and a computer program stored in a medium for implementing the same. EXECUTING THE SAME}

The present invention relates to a three-dimensional pressure mapping method, a recording medium storing a program for implementing the same, and a computer program stored in a medium for implementing the same. More specifically, the present invention relates to a three- Dimensional pressure mapping method applicable to uniform or nonuniform surface pressure mapping problems by applying the surface pressure calculation method and the pressure equivalent node load conversion method of the present invention, a recording medium storing a program for implementing the same, To a stored computer program.

 In the development process of moving objects such as air or water such as aircraft or ship, it is essential to map the external pressure to the FEM by the start of the object. In most cases, the number of mapping conditions is large and the design of the structure is continuously changed.

However, the use of the mapping function of a CFD program in this mapping process has a problem that a detailed finite element model, precise modeling, and a lot of calculation time are required.

In addition, the fluid-structure interface (FSI) mapping method using the CSD programs such as MSC / Nastran and ZAERO, which are mainly used for vibration mode analysis and aeroelastic analysis, is based on the number of connection points, Since the result of the load mapping depends on the stiffness difference of the structure, it is not suitable for the static displacement of external pressure.

That is, conventionally, a model suitable for each object must be created, and the models can not be used in other fields.

Korean Unexamined Patent Publication [10-2003-0009879] discloses a dynamic load analysis method for modeling an aircraft.

Korean Patent Publication [10-2003-0009879] (Published on February 05, 2003)

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a three-dimensional pressure interpolation method based on a radial basis function, Dimensional pressure mapping method capable of mapping uniform or non-uniform pressure by applying universal code by applying the equivalent gravity force conversion method.

According to an aspect of the present invention, there is provided a three-dimensional pressure mapping method comprising a program executed by an arithmetic processing unit including a computer, (S10) for receiving an analysis condition including a pressure value, a pressure value position information, and a control condition; A pressure interpolation step (S20) of interpolating a pressure using a three-dimensional pressure interpolation method based on a radial basis function based on the information input in the analysis condition input step (S10); A surface pressure calculation step (S30) of calculating a surface pressure of the finite element by using a finite element analysis method based on the interpolated pressure in the pressure interpolation step (S20); And a pressure mapping step (S40) of mapping a uniform or non-uniform pressure using a pressure-equivalent node force transformation method based on the surface pressure calculated in the surface pressure calculation step (S30) .

In addition, the analysis condition input step S10 includes an analysis condition storage step S11 for storing the control condition list in the form of a list, receiving the names of the control condition files; An analysis condition calling step (S12) for sequentially calling the stored control condition list in the analysis condition storage step (S11); And an input file calling step (S13) for sequentially calling a control condition file of the control condition list called in the interpretation condition calling step (S12); .

In the analysis condition storage step S11, the control condition list includes a finite element file name (FEmodel), an analysis number (LC), a pressure value position information storage file name (CPS_FileName), a pressure value information storage file name (PRE_FileName) Scale Factor).

The pressure interpolation step S20 receives the finite element, determines the triangular element CTRIA3, the rectangular element CQUAD4, and the grid GRID, and sequentially stores the information in the matrix variables A A finite element classification step S21; An algorithm for finding a center point and a normal vector according to a triangle element or a square element is applied to the matrix variables A stored in the finite element classification step S21 and the calculated result is used as matrix variables B), a center point search step (S22); A position information processing step (S23) of calling up the pressure value position information and storing the pressure value position information in a matrix variable (C); A pressure value processing step (S24) of calling up the pressure value information and storing it in a matrix variable (D); And the pressure values at the center points of all the elements to be interpolated on the basis of the pressure value position information and the pressure value information are input to the radial basis function (A, B, C, and D) (S25), which discriminates whether the element is a triangle or a rectangle, and interpolates the information using information corresponding to the triangle element and the rectangle element.

The surface pressure calculation step S30 is characterized in that the pressure value interpolated in the pressure interpolation step S20 is read and stored in a pressure load input format of Nastran.

In the pressure mapping step S40, the pressure values interpolated in the pressure interpolation step S20 are read and stored in the form of a vertex load input type of NSTRAN, and the pressure values mapped to the respective elements are equivalent And then applying a calculation algorithm of the equivalent load force (Equivalent Grid Force), and sequentially applying the interpolation ratio.

If there are various mapping conditions in one control condition file, the 3D pressure mapping method repeatedly executes the number of mapping conditions from S10 to S40, and stores the results in a cumulative manner according to an analysis condition (LC) number .

The 3D pressure mapping method is characterized in that when there are several cases of the control condition file, the number of control condition files is repeatedly executed from S10 to S40.

According to an embodiment of the present invention, there is provided a computer-readable recording medium on which a program for implementing the 3D pressure mapping method is stored.

According to an embodiment of the present invention, a program stored in a computer-readable recording medium is provided to implement the 3D pressure mapping method.

According to the three-dimensional pressure mapping method according to an embodiment of the present invention, the three-dimensional surface pressure interpolation technique based on the radiator low function is received by receiving four main factors (finite element, pressure value, pressure value position information, , The method of calculating the surface pressure of the finite element and the pressure equivalent node load conversion method are applicable to various surface pressure mapping problems of uniform or nonuniformity.

In addition, there is an effect that it is possible to solve the problem in which the object to which the pressure is to be mapped is a complex three-dimensional shape, which was not possible to directly imagine.

In addition, using the methods provided by commercial tools or using in-house code, it is possible to solve problems that were impossible to imagine.

In addition, it is possible to solve the problem that the number of analysis conditions is large and it is difficult to cope with frequent shape changes.

In addition, there is an effect that it is possible to solve the problem that different procedures, input / output formats and formats can not be commonly used for each type of event. In other words, conventionally, a model suitable for an object has to be created, and the models can not be used in other fields. However, the present invention is applicable to all fields.

1 is a flowchart of a three-dimensional pressure mapping method according to an embodiment of the present invention;
2 is a flowchart according to an embodiment of the analysis condition input step of FIG.
Figure 3 is a flow diagram according to one embodiment of the pressure interpolation step of Figure 1;
4 is a flow chart showing a loop according to the number of mapping conditions of FIG.
Figure 5 is a flow diagram showing a loop according to the number of control condition files of Figure 1;

Hereinafter, the present invention will be described in more detail with reference to the drawings. The following drawings are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the following drawings, but may be embodied in other forms. In addition, like reference numerals designate like elements throughout the specification. It is to be noted that the same elements among the drawings are denoted by the same reference numerals whenever possible. Further, it is to be understood that, unless otherwise defined, technical terms and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

FIG. 1 is a flow chart of a three-dimensional pressure mapping method according to an embodiment of the present invention, FIG. 2 is a flow chart according to an embodiment of an analyzing condition input step of FIG. 1, FIG. 4 is a flowchart showing a loop according to the number of mapping conditions in FIG. 1, and FIG. 5 is a flowchart showing a loop according to the number of control condition files in FIG.

Prior to the description, the terms used in this specification (and claims) will be briefly described.

As an example of an aircraft, the load on an aircraft can be divided into aerodynamic forces and inertial forces. Aerodynamic force refers to the external force on the aircraft, ie, the force generated by the air.

Design or analysis can be done using computer software tools (such as finite element analysis) in order to design or analyze using the force calculated from the aerodynamic force (load) applied to the aircraft.

'Finite element analysis' (FEA) is a computer simulation technique used in engineering analysis. It is common to use a numerical technique called a finite element method (FEM) and to perform mesh generation.

'Mapping' refers to the transfer of the load created by the mesh generation to the software tool.

As shown in FIG. 1, a three-dimensional pressure mapping method according to an embodiment of the present invention is a three-dimensional pressure mapping method in a form of a program executed by an arithmetic processing means including a computer, S10, a pressure interpolation step S20, a surface pressure calculation step S30, and a pressure mapping step S40.

The analysis condition input step (S10) receives the analysis conditions including the finite element, the pressure value, the pressure value position information, and the control condition. Here, the control condition refers to a process for automating a situation where various operations are simultaneously performed. That is, when four main factors (finite element, pressure value, pressure value position information, control condition) are input, it is possible to solve the complex pressure mapping problem. In this case, the finite element and the pressure value can be inputted in the source form, the pressure value position information can be inputted in the target form, and the control condition can be inputted in the control form.

At this time, the analysis condition input step S10 may include an analysis condition storage step S11, an analysis condition calling step S12, and an input file calling step S13.

The analysis condition storage step S11 receives the name of the control condition file and stores the control condition list in the form of a list. Here, the control condition file refers to a batch file for automating such operations in the case where various operations occur at the same time.

That is, the name of the control condition file stored in the folder where the control condition file (control file) is stored can be stored as a list type file. This list of stored control conditions (files) can be as many as several thousand.

Here, the control condition list includes a finite element file name (FEmodel), an analysis number (LC), a pressure value position information storage file name (CPS_FileName), a pressure value information storage file name (PRE_FileName) and an interpolation ratio (SF: ScaleFactor) .

The analysis condition calling step S12 sequentially calls the stored control condition list in the analysis condition storing step S11. That is, when a list of control conditions of one of the control condition lists is called and a series of processes for one control condition list is completed, another list of control conditions can be called. In this manner, A loop can be executed to perform a series of processes.

For example, if the object model to be interpolated is composed of one (interpreted as Single), it can be adjusted by the number of rows in the condition file. It is also possible to configure each case input branch execution mode.

The input file calling step S13 sequentially calls the control condition file of the control condition list called in the interpretation condition calling step S12. That is, when the first control condition file of the list of called control condition is called and the series of processing of the called control condition file is completed, the next control condition file can be called. In this manner, To execute a series of processing steps.

The pressure interpolation step (S20) interpolates the pressure using a three-dimensional pressure interpolation method based on a radial basis function based on the information input in the analysis condition input step (S10).

The Radial Basis Function (RBF) is a mathematical theory that performs interpolation using a reference value that knows the value at a specific position within a boundary point on a three-dimensional space. The radial basis function is a radial basis function or a radial basis function Also called.

The pressure interpolation step S20 may include a finite element classification step S21, a center point search step S22, a position information processing step S23, a pressure value processing step S24 and an element interpolation step S25 .

The finite element classification step S21 receives the finite element, identifies the triangular element CTRIA3, the rectangular element CQUAD4, and the grid GRID, and stores each information in the matrix variables A in order.

For example, the finite element file FEmodel is received, the finite element file information is sequentially read, the triangular element CTRIA3, the rectangular element CQUAD4, and the grid GRID are discriminated, and each information is stored in the matrix variable CQUAD4 , CTRIA3, GRID).

The center point searching step S22 receives the matrix variables A stored in the finite element classifying step S21 and applies an algorithm for finding a center point and a normal vector according to a triangle element or a square element, And sequentially stores the result in the matrix variables (B).

In other words, using a plane equation, normal vectors can be found for the surface of the finite element model.

For example, the matrix variables (CQUAD4, CTRIA3, and GRID) are received, and the center point and the normal vector according to the triangular element CTRIA3 and the square element CQUAD4 are calculated, and the matrix variables C4NV, C3NV, C4CEN, Can be stored. At this time, it is preferable to sequentially execute from the first row.

In the position information processing step S23, the file storing the pressure value position information is called and stored in the matrix variable C.

Here, the pressure value position information can use known pressure value position information.

The known pressure value can be either large or small for the object to be raised. At this time, the object to be raised is to be converted to match the object to which the object is to be raised, which is the pressure value of the object to be raised. That is, it is the joint value of the original information.

For example, the pressure value position information file may be input and stored in a matrix variable (CPS). At this time, it is preferable to sequentially execute from the first row.

The pressure value processing step S24 calls the pressure value information storage file and stores it in the matrix variable D.

For example, a pressure information file can be input and stored in a matrix variable (PRESS). At this time, it is preferable to sequentially execute from the first row.

The element interpolation step S25 receives the values of the generated matrix variables A, B, C and D and calculates a pressure value at the center point of all the elements to be interpolated based on the position information and the pressure value information, (Radial Basis Function) to distinguish whether the element is a triangle or a rectangle, and interpolates using information corresponding to the triangle element and the rectangle element.

For example, based on the values stored in the matrix variables CQUDA4, CTRIA3, C4CEN, C3CEN, CPS, and PRESS, and based on the pressure value information and the pressure value position information of the input element, the triangular element CTRIA3, (C4PRE, C3PRE) in accordance with the equation (CQUAD4). At this time, it is preferable to sequentially execute from the first row.

If structural nodes X, aerodynamic nodes Y, and displacement values (= pressure values) of structural nodes located in space are defined as u, we can express as follows.

The pressure values between given boundary nodes can be defined as an interpolation function S that represents the pressure at any point in the region and can be expressed as:

Where X _j is the boundary nodes that know the pressure value, p (X) is the third order polynomial to improve the accuracy of the three-dimensional correction, and Φ is the finite radiator low function of the mth order positive · ∥ is the Euclidean length function.)

In the case of 3D, if the coordinates of the nodal points are expressed as x, y, z, the Euclidean distance can be expressed as the distance between the nodal points as follows.

When using Gaussian function with radiator low function (RBF)

, The polynomial equation is not defined. In order to obtain the coefficient, the additional condition that the order of the polynomial q is equal to or smaller than the polynomial p (Othogonal condition)

Should be used.

Therefore, using the above equations,

As shown in Fig.

Here, A represents an interpolation matrix,

As shown in Fig.

Further, in the case of the three-dimensional case, [P], {u}, {alpha}, and {c}. {0}. The matrix [0]

As shown in Fig.

를 만족하는 보간값 x_j를 구하기 위해

를 적용하여 3차원에서 보정 다항식이 표함된 경우는 다음식Known Constraints

To obtain an interpolation value x _j that satisfies

And the correction polynomial is expressed in three dimensions by applying the following equation

And interpolation function to obtain each interpolation value is defined using the following equation

Respectively.

The surface pressure calculation step S30 calculates the surface pressure of the finite element using the finite element analysis method based on the pressure interpolated in the pressure interpolation step S20.

At this time, the surface pressure calculation step (S30)

The pressure value interpolated in the pressure interpolation step (S20) may be read and stored as a pressure load input type format of NASSTRAN. Here, NASTRAN (NASA Structural Analysis Computer System) is a structural analysis computer system developed by National Aeronautics and Space Administration (NASA). It is used to automate numerical analysis and simulation for structural design of aircraft, etc. Computer Aided Engineering (CAE) tool.

For example, the matrix parameters (C4PRE, C3PRE) stored in the pressure interpolation step (S20) may be input. At this time, the analysis number (LC) can be further input. Thereafter, it can be stored as a pressure load input format (**** (LC number) _PLOAD4.nap **** (LC number) _PLOAD.nap) of NASTRAN.

The pressure mapping step S40 maps the uniform or nonuniform pressure using a pressure-equivalent node force transformation method based on the surface pressure calculated in the surface pressure calculation step S30.

At this time, the pressure mapping step (S40) reads the pressure value interpolated in the pressure interpolation step (S20) and stores the pressure value in the form of a vertex load input type of NSTRAN, and the pressure value mapped to each element is equivalent And then applying an Equivalent Grid Force calculation algorithm to sequentially process the data and applying an interpolation ratio.

In other words, the pressure acting on the surface of the finite element model can be distributed by the equivalent load of each material point of the component.

For example, applying the Equivalent Grid Force calculation algorithm based on matrix variables (C4PRE, C3PRE, C4NV, C3NV, analysis number (LC) and interpolation ratio (SF) It can be saved as a load input format (**** (LC number) _FLOAD4.nap).

The information transfer between the aerodynamic lattice model and the structural finite lattice model is mainly performed using the interpolation function G from the structural node points of the grid model to the aerodynamic limiting nodes,

(Where h denotes aerodynamic constraint nodes (known values) and x denotes structural finite element nodes.)

As shown in Fig.

Applying the principle of virtual work to the relationship between the aerodynamic force {F _a } obtained from the aerodynamic lattice and the equivalent load {F _s } acting on the structural lattice,

Can be obtained as follows. In order for the equation about the load acting on the structural grid to always be established for an artificial virtual displacement,

, Which can be used to determine the force (pressure) transmitted from known aerodynamic nodes to structural nodes.

To simplify this process,

Respectively. Therefore,

Can be mapped to the pressure value at any mapped structural node.

As shown in FIG. 4, when there are various mapping conditions in one control condition file, the 3D pressure mapping method according to the embodiment of the present invention repeatedly executes S10 to S40 as many as the number of mapping conditions, Are accumulated in accordance with an analysis condition (LC) number.

That is, when the finite element model is complicated, it is possible to set each model as a zone and apply it.

As shown in FIG. 5, the 3D pressure mapping method according to the embodiment of the present invention is characterized in that when there are several cases of the control condition file, the number of control condition files is repeatedly executed from S10 to S40 .

Consequently, the 3D pressure mapping method according to an embodiment of the present invention relates to a programming technique (matlab) capable of integrating, processing, and outputting individual algorithms.

Although the three-dimensional pressure mapping method according to one embodiment of the present invention has been described above, the present invention is applicable to a computer readable recording medium in which a program for implementing a three-dimensional pressure mapping method is stored, It goes without saying that the program stored in the recording medium can also be implemented.

That is, those skilled in the art will readily understand that the above-described three-dimensional pressure mapping method can be provided in a recording medium readable by a computer by tangibly embodying a program of instructions for implementing the same. In other words, it can be implemented in the form of a program command that can be executed through various computer means, and can be recorded on a computer-readable recording medium. The computer-readable recording medium may include program commands, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer-readable recording medium may be those specially designed and configured for the present invention or may be those known and available to those skilled in the computer software. Examples of the computer-readable medium include magnetic media such as hard disks, floppy disks and magnetic tape, optical media such as CD-ROMs and DVDs, and optical disks such as floppy disks. Magneto-optical media and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, USB memory, and the like. The computer-readable recording medium may be a transmission medium such as a light or metal line, a wave guide, or the like, including a carrier wave for transmitting a signal designating a program command, a data structure, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

S10: Inputting the analysis condition
S11: Step of storing analysis condition
S12: Interpreting condition call step
S13: Input file call step
S20: Pressure interpolation step
S21: Finite element classification step
S22:
S23: Position information processing step
S24: pressure value processing step
S25: Element interpolation step
S30: Surface pressure calculation step
S40: Pressure mapping step

Claims (10)

A three-dimensional pressure mapping method in a form of a program executed by an arithmetic processing means including a computer,
(S10) receiving an analysis condition including a finite element, a pressure value, position information of the pressure value, and control condition list information;
Based on the analysis conditions input in the analysis condition input step (S10), the pressure value at the center point of all the elements to be interpolated is interpolated using the three-dimensional pressure interpolation method based on the radiator basal function (S20);
A surface pressure calculation step (S30) of calculating a surface pressure of the finite element by using a finite element analysis method based on the pressure value interpolated in the pressure interpolation step (S20); And
A pressure for mapping the uniform or non-uniform pressure of the interpolated pressure value using the Equivalent Grid Force transformation method based on the surface pressure of the finite element calculated in the surface pressure calculation step S30 Mapping step S40;
/ RTI >
In the analysis condition input step (S10)
Wherein the control condition list information is information of a process for automating a plurality of operations simultaneously.
The method according to claim 1,
The analysis condition input step (S10)
An analysis condition storage step (S11) of storing a control condition list in the form of a list by receiving the name of the control condition file;
An analysis condition calling step (S12) for sequentially calling the stored control condition list in the analysis condition storage step (S11); And
An input file calling step (S13) for sequentially calling a control condition file of the control condition list called in the interpretation condition calling step (S12);
Dimensional pressure mapping method.
3. The method of claim 2,
In the analysis condition storage step S11, the control condition list
A finite element file name (FEmodel), an analysis number (LC), a pressure value position information storage file name (CPS_FileName), a pressure value information storage file name (PRE_FileName), and an interpolation ratio (ScaleFactor).
The method according to claim 1,
The pressure interpolation step (S20)
Which receives the finite element from the analysis condition input step S10 and sequentially stores the information in the matrix variables A, determines the triangular element CTRIA3, the square element CQUAD4, and the grid GRID, Element classification step S21;
An algorithm for finding a center point and a normal vector according to a triangle element or a square element is applied to the matrix variables A stored in the finite element classification step S21 and the calculated result is used as matrix variables B), a center point search step (S22);
A position information processing step (S23) of calling up the pressure value position information and storing the pressure value position information in a matrix variable (C);
A pressure value processing step (S24) of calling up the pressure value information and storing it in a matrix variable (D); And
Based on the pressure value position information and the pressure value information, the pressure value at the center point of all the elements to be interpolated is input to the radial basis function (A, B, C and D) (S25) of interpolating the triangle or quadrangle using information corresponding to the triangular and quadrangular elements by applying a three-dimensional pressure interpolation method based on the three-dimensional pressure interpolation method.
Dimensional pressure mapping method.
The method according to claim 1,
The surface pressure calculation step (S30)
Wherein the pressure value interpolated in the pressure interpolation step (S20) is read and stored as a pressure load input type format of Nastran.
The method according to claim 1,
The pressure mapping step (S40)
The pressure value interpolated in the pressure interpolation step (S20) is read and stored as a vertex load input type format of NSTRAN,
Wherein a pressure value mapped to each element is sequentially processed by applying an Equivalent Grid Force calculation algorithm, and an interpolation ratio is applied.
The method according to claim 1,
The three-dimensional pressure mapping method
When there are various mapping conditions in one control condition file, the number of mapping conditions is repeatedly executed from S10 to S40, and the results are accumulated and stored in accordance with the number of the analysis condition (LC) .
The method according to claim 1,
The three-dimensional pressure mapping method
When there are several cases of the control condition file, the number of control condition files is repeatedly executed from S10 to S40.
A computer-readable recording medium on which a program for implementing the three-dimensional pressure mapping method according to any one of claims 1 to 8 is stored.
A program stored in a computer-readable recording medium for implementing the three-dimensional pressure mapping method according to any one of claims 1 to 8.

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