A fast calculation method for wing bending deformation

Abstract

The rapid calculation method for the wing bending deformation of this application. When the wing structure is under the action of external loads, it will produce bending deformation. When conducting engineering analysis on it, it is usually necessary to use finite element technology to calculate the magnitude of the deformation. However, due to the large number of design variables, the efficiency of the fine finite element analysis method is relatively low. The design of this application includes: constructing a cubic polynomial for the wing bending deformation along the span direction based on the assumption that the total spanwise length remains unchanged after the wing deformation; obtaining the boundary conditions of the fixed wing root and the free wing tip, and calculating the undetermined coefficients of the polynomial; substituting the undetermined coefficients of the polynomial into the deflection curve equation to obtain the bending deformation of the wing structure along the span direction. By using the technology of polynomial fitting to approximately calculate the displacement deformation result of the wing structure under the action of loads, the bending deformation of the wing structure can be quickly obtained on the premise of ensuring a certain accuracy, and it has good engineering application effects.

Description

Technical Field

[0001] This application belongs to the field of wing structure design, and particularly relates to a method for quickly calculating the bending deformation of a wing. Background Art

[0002] Since the deformation of the wing under load is mainly bending-torsion deformation, and the bending-torsion deformation of the wing in turn affects the distribution of the aerodynamic load on the wing surface, thereby affecting the lift and the maneuverability of the aircraft. At the same time, the change in the aerodynamic load will further affect the deformation of the aircraft wing structure. When performing the simulation calculation of the bending deformation of the aircraft wing structure, due to the large number of design variables and complex parameters, the amount of calculation will increase accordingly.

[0003] Therefore, how to achieve efficient simulation calculation of the bending deformation of the aircraft wing structure is a problem that needs to be solved. Summary of the Invention

[0004] The purpose of this application is to provide a method for quickly calculating the bending deformation of a wing to solve the problems of a large number of design variables and complex parameters in the existing simulation calculation of the bending deformation of the aircraft wing structure.

[0005] The technical solution of this application is: a method for quickly calculating the bending deformation of a wing, including:

[0006] Constructing a cubic polynomial for the wing to bend and deform along the span direction based on the assumption that the total span length remains unchanged after the wing deforms;

[0007] Obtaining the boundary conditions of the fixed wing root and the free wing tip, and calculating the undetermined coefficients of the cubic polynomial through an analysis model including attributes, loads, and constraint conditions;

[0008] Substituting the undetermined coefficients of the cubic polynomial into the deflection curve equation to obtain the bending deformation of the wing structure along the span direction.

[0009] Preferably, the cubic polynomial is: ; where: are the undetermined coefficients of the polynomial, is the spanwise coordinate value of the local coordinate system after the wing deforms.

[0010] Preferably, the boundary conditions of the fixed wing root and the free wing tip include:

[0011] ;

[0012] Among them, is the boundary condition at the wing root, is the first derivative of, is the boundary condition at the free wing tip, is the second derivative of, is the wing tip deflection, is the deflection at the free end of the wing tip.

[0013] Preferably, the bending deformation of the wing structure in the spanwise direction is: , where is the wing tip deflection, is the deflection at the free end of the wing tip.

[0014] Preferably, the undetermined coefficients of the cubic polynomial are respectively , where is the wing tip deflection, is the deflection at the free end of the wing tip.

[0015] The rapid calculation method for the bending deformation of the wing in this application approximates the displacement deformation result of the wing structure under load by means of polynomial fitting technology, and can quickly obtain the bending deformation of the wing structure on the premise of ensuring a certain accuracy, and has a good engineering application effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions provided in this application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.

[0017] Figure 1 is the overall flow schematic diagram of this application;

[0018] Figure 2 is the schematic diagram of the wing structure of this application;

[0019] Figure 3 is the analysis model including attributes, loads and boundary conditions of this application;

[0020] Figure 4 is the schematic diagram of the bending deformation result of the wing structure of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] A rapid calculation method for the bending deformation of a wing, as Figure 1 , includes the following steps:

[0023] Step S100, constructing a cubic polynomial for the bending deformation of the wing in the spanwise direction based on the assumption that the total length of the wing in the spanwise direction remains unchanged after deformation ;

[0024] Wherein: are the undetermined coefficients of the polynomial, is the spanwise coordinate value of the local coordinate system after the wing deforms.

[0025] The wing structure is as Figure 2 shown. In the local coordinate system, the origin is defined as the outer end point after the deformation of the previous section of the wing, and the coordinate axes are parallel to the global coordinate system.

[0026] Step S200: Obtain the boundary conditions of the fixed wing root and the free wing tip, and calculate the undetermined coefficients of the cubic polynomial through an analysis model including properties, loads, and constraint conditions. The undetermined coefficients of the cubic polynomial are respectively ; In the formula, is the wing tip deflection, is the deflection of the free end of the wing tip.

[0027] The boundary conditions of the fixed wing root and the free wing tip include:

[0028] ;

[0029] Wherein, is the boundary condition at the wing root, is the first derivative of, is the boundary condition of the free end of the wing tip, is the second derivative of, is the wing tip deflection, is the deflection of the free end of the wing tip.

[0030] The analysis model including properties, loads, and constraint conditions is as Figure 3 shown. The aerodynamic load is connected to the nodes of the analysis model through spatial interpolation, and the end is fixed.

[0031] Step S300: Substitute the undetermined coefficients of the cubic polynomial into the deflection curve equation to obtain the bending deformation of the wing structure along the spanwise direction ;

[0032] It can be seen from the deflection curve equation that only by knowing the wing tip deflection can the bending deformation result of the wing structure along the spanwise direction be calculated, as Figure 4 .

[0033] In summary, due to the bending deformation of the wing structure under the action of external loads. When performing engineering analysis on it, it is usually necessary to use finite element technology to calculate the magnitude of the deformation. However, due to the large number of design variables, the efficiency of the fine finite element analysis method is relatively low.

[0034] With the help of the technology of polynomial fitting, this application approximates the displacement and deformation results of the wing structure under the action of load, and can quickly obtain the bending deformation of the wing structure on the premise of ensuring a certain accuracy, which has a good engineering application effect.

[0035] Finally, it should be noted that: in the attached drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved. For other structures, reference can be made to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0036] Finally: The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for rapid calculation of wing bending deformation, characterized in that: include: Based on the assumption that the total span length of the wing remains unchanged after deformation, a cubic polynomial of the wing bending deformation along the span direction is constructed; Obtain the boundary conditions of the fixed wing root and the free end of the wing tip, and calculate the unknown coefficients of the cubic polynomial through the analytical model including properties, loads and constraints; Substituting the unknown coefficients of the cubic polynomial into the deflection curve equation, the bending deformation of the wing structure along the span direction is obtained; The cubic polynomial is: f(x)=m+nx+px 2 +qx 3 ; Where: m, n, p, q are the unknown coefficients of the polynomial, and x is the spanwise coordinate value of the local coordinate system after the wing is deformed; The boundary conditions of the fixed wing root and the free end of the wing tip include: f(0)＝0 f′(0)＝0 f″(L i )=0; Where f(0) is the boundary condition at the wing root, f′(0) is the first derivative of f(0), and f(L i ) is the boundary condition of the free end of the wing tip, f″(L i ) is f(L i ), δ i t is the wing tip deflection, L i is the free end deflection of the wing tip; The bending deformation of the wing structure along the span direction is: In the formula, δ i t is the wing tip deflection, L i is the free end deflection of the wing tip; The unknown coefficients of the cubic polynomial are respectively m=0, n=0, In the formula, δ i t is the wing tip deflection, L i is the deflection of the free end of the wing tip.

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