KR20030009879A - Analysis method for dynamic load in aircraft modeling - Google Patents

Abstract

PURPOSE: A method for analyzing dynamic load in airplane modeling is provided to simply calculate the dynamic load of an airplane by inserting input data and to reduce the time for developing an airplane by reducing the time for calculating the dynamic load, and to make a computer terminal offer prompt motion speed and result. CONSTITUTION: A user calls a grid strength file and an MPC strength file by driving a computer terminal embedding a Nastran file(S1). The user inputs data including a grid file, a matched DOF file, a standard point coordinate, a time table, and the name of a file to be outputted(S2). The input data and strength files are read(S3). The grid coordinate is transformed(S4). The time step is increased(S5). The grid number is increased(S7). The grid coordinate is transformed(S8). The grid strengths are added(S10). If a grid is a final grid, a final standard point is decided(S12). Thereafter, a final time step is decided(13).

Description

Dynamic load analysis method during aircraft modeling {ANALYSIS METHOD FOR DYNAMIC LOAD IN AIRCRAFT MODELING}

The present invention relates to a dynamic load analysis method when modeling an aircraft. Specifically, in order to calculate dynamic load in modeling of an aircraft that has been carried out with many grids and elements, a characteristic method of summing internal loads rather than external loads of an aircraft is used. The present invention relates to a dynamic load analysis method for modeling an aircraft characterized in that the dynamic load of the aircraft is calculated.

In general, modeling of an object moving in a medium such as air or water, such as an aircraft or a ship, requires an analysis of the dynamic loads that the aircraft or ship bears as it moves. Leading with the structural analysis program developed for the ship's structural analysis, the groundbreaking method of finite element analysis, which performs the analysis of specific variables, is presented.It is widely used for linear, nonlinear analysis and various geometric analysis of three dimensions. have.

Specifically, the finite element analysis method is expressed as an expression so that a desired value can be calculated at an arbitrary point in the whole structure or physical system to be analyzed, and thus can be used for all points in the object. It is a method of interpreting desired values by simultaneous algebraic equations without solving ordinary differential or partial differential equations.

However, in the process of modeling an aircraft or a ship by the finite element analysis method, a method of analyzing dynamic loads is generally equivalent to modeling an aircraft using a beam and obtaining various dynamic loads from the model. Dynamic loads also have many problems because they have many problems reflecting the actual model.

In particular, the method of using external load, which is the external load of the aircraft, is very complicated due to the many variables of the calculation formula, and it takes a lot of calculation time in the computer even if you program it and take a lot of effort to input many variables. It is also necessary.

The present invention was derived to solve the above problems, and an object of the present invention is to provide a method for simply calculating dynamic loads in modeling that requires load calculation according to dynamic characteristics such as aircraft and ships.

Other objects of the present invention will be described in more detail in the configurations and operations described below.

1 is a flow chart showing a preferred analysis method according to the present invention.

Dynamic load analysis method in modeling the aircraft according to the present invention comprises the steps of obtaining a grid force file using a Nastran demap, reading the force force file, the resultant file of Nastran, transforming grid coordinates, time Increasing the step, increasing the reference point, increasing the grid number, converting the coordinates of the grid force, determining whether the grid forces are summed or interrupting with increasing the grid number; If the result of the determination of the sum of the grid forces is correct, the step of summing the grid forces, determining whether it is the last grid, interrupting it to increase the grid number if it is not the last grid, and determining whether it is the last reference point or not is the last reference point Interrupt with increasing points, last Determine if the time step and is characterized in that it comprises the step, and storing the results, and steps shown in a variety of screens according to the display the stored results type that interrupts a phase of not the last time step increases the time step.

Preferably the grid force is the dynamic load at the reference point, and this dynamic load is the bending moment, torsion, shear force, and the step of summing the grid forces is the respective variable. Summing up the values for.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

According to FIG. 1, methods for calculating dynamic loads in modeling of an aircraft are shown in stages.

Specifically, the user drives a computer terminal in which a Nastran file including DMAP is embedded to call the grid force file and the MPC force file (step S1).

At this time, the user inputs data, and the data includes a grid file, a matched DOF file, a reference point coordinate, a time table, a file name to be output, and the like (step S2).

When data input to the computer is completed, the input data and force files are read (step S3).

Then, grid coordinate transformation (step S4), time step increment (step S5), reference point increment (step S6), grid number increment (step S7) and grid coordinate transformation (step S8) are performed.

As a result of the determination in step S9 of determining whether the grid forces are added, step S10 of summing the grid forces is performed if YES, and interrupted to step S7 of increasing the grid number of the NO surface.

In this case, the sum result, which is the result of performing the step S10, means the dynamic load at the reference point.

After step S10, it is determined whether it is the last grid (step S11), and if it is not the last grid, it is interrupted by step S7 of incrementing the grid number, and if it is the last grid, step S12 is determined whether it is the last reference point.

In step S12, a step S13 of determining whether the last reference point is the last time step is performed, and if it is not the last reference point, the process is interrupted by step S6 of incrementing the reference point.

If it is not the last type step in step S13, it interrupts to step S5 of incrementing the time step, and if it is the last type step, step S14 is recorded.

Through this process, the computer performing the steps according to the present invention can easily calculate dynamic loads in modeling requiring load calculation according to dynamic characteristics such as aircraft or ship, and according to the recording type of the result, Can produce output

As described above, the preferred embodiments of the present invention have been described in detail, but those skilled in the art of the present invention may be modified or modified without departing from the spirit and scope of the present invention. You will know that you can.

According to the present invention as described above, in the process of modeling an aircraft or a ship by a finite element analysis method, the aircraft is modeled by using a beam and a simple input without using a method of obtaining various dynamic loads from the model. By inserting the data, the dynamic load of the aircraft can be calculated simply.

And, by using a simple calculation method according to the invention the computer terminal performing this task can provide a fast operating speed and results, the time required to calculate the dynamic load during aircraft development on the user side is greatly reduced The overall time of aircraft development is reduced.

In addition, since the user does not have to perform a simple repetitive work, the work efficiency is improved and the development cost is reduced.

Claims (2)

In the dynamic load analysis method at the time of aircraft modeling, A data reading step of reading a grid force file and an empty force file using Nastran's demap; Converting and increasing the grid coordinates, increasing the time step, increasing the reference point, increasing the grid number and transforming the coordinates of the grid force; Determining whether the grid forces are summed or not, adding the grid numbers to interrupt the sum of the grid forces; Summing up the grid forces if it is determined that the grid forces are added; Determining whether it is the last grid and interrupting the conversion and incrementing step of increasing the grid number if it is not the last grid, and performing the next step if the last grid; Determining whether it is the last reference point and interrupting the conversion and increment step of incrementing the reference point if it is not the last reference point, and performing the next step if it is the last reference point; Determining whether it is the last time step and interrupting by incrementing the time step if it is not the last time step, and performing the next step if the last time step; A dynamic load analysis method for modeling an aircraft, comprising the steps of storing a result and displaying the result in various forms according to a display format. The method of claim 1, The grid force is a dynamic load analysis method during aircraft modeling, characterized in that the dynamic load at the reference point including the bending moment, torsion, and shear force.