CN109684674A - A kind of hatch door aerodynamic loading processing method - Google Patents

Abstract

The invention belongs to aeroelasticity fields, and in particular to a kind of hatch door aerodynamic loading processing method.By load processing method, hatch door finite element grid aerodynamic loading can be used directly, calculate control errors within an acceptable range, and computational accuracy is high, simple and quick, widely applicable.

Description

A kind of hatch door aerodynamic loading processing method

Technical field

The invention belongs to aeroelasticity fields, and in particular to a kind of hatch door aerodynamic loading processing method.

Background technique

Aerodynamic loading calculates and finite element model calculating requires aircraft configuration carrying out grid dividing, due in each field Inside have oneself solving precision and efficiency requirements, it is different for mesh-density demand, so as to cause structure finite element grid and Aerodynamic loading calculating grid configuration is widely different, it cannot be guaranteed that finite element grid and LOAD FOR grid are completely coincident.Therefore it needs Seek a kind of aerodynamic data processing method, to realize that aerodynamic data calculates grid in finite element model and aerodynamic loading calculates net Transmitting on lattice, and efficiently accurately load processing method is also to guarantee the important means of finite element model computational accuracy.

Summary of the invention

Goal of the invention: a kind of hatch door aerodynamic loading processing method, to guarantee finite element model computational accuracy.

Technical solution: a kind of hatch door aerodynamic loading processing method, steps are as follows for calculating:

The first step reads pneumatic total load always away from (comprising pressure heart position) file, pneumatic distributed load (CP value) file, pneumatically Grid model；

Second step reads hatch door finite element model (including node location, triangular element, quadrilateral units)；

Third step will calculate pneumatic distributed load (CP value) processing to hatch door finite element mould using Spline interpolation method On type node location；

4th step, by integrating to obtain the section of each unit to hatch door finite element model triangular element, quadrilateral units Point power；

5th step, according to pressure heart position calculate finite element model nodal force it is total load always away from, and with aerodynamic loading it is original always It carries always away from comparison, carries out analytical error, if calculate error thinks acceptable within 3%, otherwise repaired using little increment weighting Correction method is modified nodal force, by control errors within 3%.

6th step exports finite element model nodal force according to Nastran reading format.

Beneficial to calculating effect: passing through load processing method, hatch door finite element grid aerodynamic loading can be used directly, be calculated Within an acceptable range, computational accuracy is high for control errors, simple and quick, widely applicable.

Detailed description of the invention

Fig. 1 is program flow diagram；

Fig. 2 is aerodynamic grid and hatch door FEM model schematic diagram；

Fig. 3 is finite element model nodal force distribution schematic diagram；

Fig. 4 is that Nastran reading format exports schematic diagram.

Specific embodiment

A kind of hatch door aerodynamic loading processing method, this method specifically calculate that steps are as follows:

The first step reads pneumatic total load always away from (comprising pressure heart position) file, pneumatic distributed load (CP value) file, gas Dynamic mesh model；

Second step reads hatch door finite element model (including node location, triangular element, quadrilateral units), such as Fig. 1 institute Show；

Third step will calculate pneumatic distributed load (CP value) processing to hatch door finite element mould using Spline interpolation method On type node location；

Wherein, Spline interpolation method:

It is located at N number of independent point (x_i,y_i) functional value W on (i=1,2 ..., N)_iIt is given, then general surface batten letter Number W_(x,y)It can be expressed as:

In formula: r_i ²=(x-x_i)²+(y-y_i)²

ε is one a small amount of, is to calculate set by higher derivative and Control curve Curvature varying emergency degree.Generally want It asks: ε < < min (r_i ²) (i=1,2 ..., N and r_iFor non-zero value)

COEFFICIENT K_i(i=1,2 ..., N) and a₀、a₁、a₂It is determined by following linear equation group:

In formula:

Solve system of equation (2), obtains COEFFICIENT K_iAnd a₀、a₁、a₂, Curved surface spline interpolating function can be obtained by substituting into formula (1) W_(x,y)。

4th step, by integrating to obtain each list to face elements such as hatch door finite element model triangular element, quadrilateral units The nodal force of member, as shown in Figure 2；

5th step calculates total load of finite element model nodal force always away from and always carrying with aerodynamic loading always according to pressure heart position Away from comparing, analytical error.If calculate error thinks acceptable within 3%, amendment side is otherwise weighted using little increment Method is modified nodal force, by control errors within 3%, as shown in table 1.

1 hatch door aerodynamic loading of table handles error

Wherein, little increment weights modification method:

If pneumatically always carrying total square is F_z、M_x、M_y, load treated panel load is P_i(i=1,2 ... ..., N), N is Finite element node number, node location coordinate are x_i、y_i。

If weighting coefficient is b₀、b₁And b₂, enable revised panel load P_i' are as follows:

P_i'=P_i+P_i(b₀+b₁x_i+b₂y_i)

Then have:

Coefficient b can be obtained by solving above formula₀、b₁And b₂, substituting into can be calculated revised panel load P_i'。

6th step exports finite element model nodal force according to Nastran reading format, as shown in Figure 4.

As can be seen that passing through load processing method, hatch door finite element grid aerodynamic loading can be used directly, calculate error Within an acceptable range, computational accuracy is high for control, simple and quick, widely applicable.

Claims (4)

1. a kind of hatch door aerodynamic loading processing method, it is characterised in that: steps are as follows for calculating:

The first step reads pneumatic total load always away from file, pneumatic distributed load file, aerodynamic grid model；

Second step reads hatch door finite element model；

Third step will calculate pneumatic distributed load processing to hatch door finite element model node location using Spline interpolation method On；

4th step, by integrating to obtain the nodal force of each unit to hatch door finite element model triangular element, quadrilateral units；

5th step, according to pressure heart position calculate finite element model nodal force it is total load always away from, and with aerodynamic loading it is original it is total carry always Away from comparison, analytical error is carried out, if calculate error thinks acceptable within 3%, amendment side is otherwise weighted using little increment Method is modified nodal force, by control errors within 3%.

6th step exports finite element model nodal force according to Nastran reading format.

2. a kind of hatch door aerodynamic loading processing method according to claim 1, it is characterised in that: spline function in step 3 Interpolation method is as follows:

It is located at N number of independent point (x_i,y_i) functional value W on (i=1,2 ..., N)_iIt is given, then general surface spline function W_(x,y)It can be expressed as:

In formula: r_i ²=(x-x_i)²+(y-y_i)²

ε is one a small amount of, is to calculate set by higher derivative and Control curve Curvature varying emergency degree；ε<<min(r_i ²)(i =1,2 ..., N and r_iFor non-zero value；

COEFFICIENT K_i(i=1,2 ..., N) and a₀、a₁、a₂It is determined by following linear equation group:

In formula:Solve system of equation (2), obtains COEFFICIENT K_iAnd a₀、a₁、a₂, substituting into formula (1) can Obtain Curved surface spline interpolating function W_(x,y)。

3. a kind of hatch door aerodynamic loading processing method according to claim 1, it is characterised in that: little increment weights amendment side Method:

If pneumatically always carrying total square is F_z、M_x、M_y, load treated panel load is P_i(i=1,2 ... ..., N), N is finite element Node number, node location coordinate are x_i、y_i；

If weighting coefficient is b₀、b₁And b₂, enable revised panel load P_i' are as follows:

P_i'=P_i+P_i(b₀+b₁x_i+b₂y_i)

Then have:

Coefficient b can be obtained by solving above formula₀、b₁And b₂, substituting into can be calculated revised panel load P_i'。

4. a kind of hatch door aerodynamic loading processing method according to claim 1, it is characterised in that: finite element mould in step 2 Type includes: node location, triangular element, quadrilateral units.