CN107066653B

CN107066653B - Aeroelasticity analysis method considering dynamic characteristics of engine

Info

Publication number: CN107066653B
Application number: CN201611161889.7A
Authority: CN
Inventors: 党云卿; 李俊杰; 胡志勇
Original assignee: Xian Aircraft Design and Research Institute of AVIC
Current assignee: Xian Aircraft Design and Research Institute of AVIC
Priority date: 2016-12-15
Filing date: 2016-12-15
Publication date: 2020-12-29
Anticipated expiration: 2036-12-15
Also published as: CN107066653A

Abstract

The invention belongs to the technical field of aeroelasticity analysis of airplanes, and relates to an aeroelasticity analysis method considering dynamic characteristics of an engine. Extracting an engine reference point; step two, establishing the following matrix according to the extracted engine reference point position and the power characteristic of the engine: engine thrust stiffness correction matrix

Wherein j is the engine number, F is the thrust vector of the engine reference point position, and M is the moment vector caused by the engine thrust; gyro moment damping correction matrix

Wherein, omega is the angular velocity of the engine reference point position, and theta is the rotation angle vector of the engine reference point position; step three, according to the correction matrix established in the step two, correcting the aeroelastic motion equation without considering the dynamic characteristic of the engine,

ΔM^*＝Φ^TΔMΦ，ΔD^*＝Φ^TΔDΦ，ΔK^*＝Φ^TΔ K Φ, wherein Δ M^*Is a quality correction matrix, phi is a mode matrix; and step four, calculating the aeroelastic stability or dynamic response according to the corrected aeroelastic motion equation.

Description

Aeroelasticity analysis method considering dynamic characteristics of engine

Technical Field

The invention belongs to the technical field of aeroelasticity analysis of airplanes, and relates to an aeroelasticity analysis method considering dynamic characteristics of an engine.

Background

More and more modern aircraft are equipped with engines with large bypass ratios in order to improve fuel efficiency, reduce noise emissions, and take environmental and energy considerations into account. The effect of large diameter rotating blades on the dynamics of this type of aircraft needs to be studied. The influence of the relevant dynamic characteristics of the traditional calculation method on the large rotating mass engine on the elastic aircraft, the structural vibration problem caused by the structural coupling of the engine and the elastic wing, and the gyroscopic effect are not considered in the aeroelasticity analysis. At present, no aeroelasticity analysis method considering the influence factors is provided at home.

Disclosure of Invention

The purpose of the invention is as follows: a method for aeroelasticity analysis considering the influence of engine thrust and gyro moment is provided.

The technical scheme of the invention is as follows: a method of aeroelastic analysis taking into account the dynamic characteristics of an engine, said method comprising the steps of:

extracting an engine reference point;

step two, establishing the following matrix according to the extracted engine reference point position and the power characteristic of the engine:

engine thrust stiffness correction matrix

Wherein j is the engine number, F is the thrust vector of the engine reference point position, and M is the moment vector caused by the engine thrust;

gyro moment damping correction matrix

Wherein, omega is the angular velocity of the engine reference point position, and theta is the rotation angle vector of the engine reference point position;

step three, according to the correction matrix established in the step two, correcting the aeroelastic motion equation without considering the dynamic characteristic of the engine,

ΔM^*＝Φ^TΔMΦ，ΔD^*＝Φ^TΔDΦ，ΔK^*＝Φ^TΔKΦ

wherein, Δ M^*Is a quality correction matrix, phi is a mode matrix;

and step four, calculating the aeroelastic stability or dynamic response according to the corrected aeroelastic motion equation.

Preferably, if the engine has a pitch angle β, a transformation matrix is generated as follows, and a stiffness correction matrix is generated

Or damping correction matrix

Then the above-mentioned steps three and four are performed.

Preferably, the position of the engine in the aeroelastic motion equation matrix is determined through an engine reference point, wherein the engine reference point is the gravity center of the engine or the loading point of the thrust of the engine.

The invention has the beneficial effects that: the aeroelasticity analysis method considering the influence of engine thrust and gyro moment is provided. The influence of engine thrust and gyroscopic effect can be considered in the dynamic simulation model of the airplane with the engine, so that the aeroelasticity analysis precision of the whole airplane is improved, and aeroelasticity design is guided better. The analysis method is simple and convenient to operate and has higher engineering application value.

Drawings

FIG. 1 is a schematic view of a finite element model of an aircraft;

FIG. 2 is a comparison graph of symmetric bending vibration and flutter of a wing;

FIG. 3 is a comparison graph of antisymmetric bending torsional flutter results of wings.

Detailed Description

1 extracting an engine reference point:

before the aeroelastic analysis is performed, a structural finite element model, for example an aircraft finite element model, is necessary as shown in fig. 1. 1361 nodes are shared in the finite element model, and the positions of the node numbers of the left engine gravity center and the right engine gravity center in all the nodes are 168 and 968, and the engine gravity center nodes are extracted engine reference points. According to the finite element model, the dimension of the mass Matrix M, the dimension of the damping Matrix D and the dimension of the rigidity Matrix K are 8166, and the positions of the corresponding matrixes of the gravity center points of the left engine and the right engine are Matrix (1003: 1008) Matrix (5803: 5808, 5803: 5808).

2 assuming that the power characteristics of the left and right engines are identical, the thrust vector and the torque vector of the engines are F (-16501.2, 0, 0) M, respectively_vThe turning angle vector and the angular speed of the engine are (0, 15008.6, 0), θ (-150.2, 16.0, 30.5) Ω -105, respectively. The corresponding correction matrices are:

if the engine has an installation pitch angle beta of 3 degrees, a conversion matrix needs to be generated

Multiplying the obtained conversion matrix by a correction rigidity matrix and a correction damping matrix to obtain a correction matrix considering the mounting pitch angle state of the engine:

and 3, bringing the correction matrix of the previous step into an aeroelastic motion equation without considering the dynamic characteristic of the engine.

ΔM^*＝Φ^TΔMΦ，ΔD^*＝Φ^TΔDΦ，ΔK^*＝Φ^TΔKΦ

Wherein, Δ M^*For the quality correction matrix, Φ is the mode matrix.

And 4, defining the aeroelasticity stability analysis state, and obtaining two unstable flutters according to the calculation result, wherein the two unstable flutters are respectively wing symmetric bending torsion flutter and wing antisymmetric bending torsion flutter. The normalized results of symmetric wing bending flutter considering the dynamic characteristic of the engine and symmetric wing bending flutter not considering the dynamic characteristic of the engine are shown in a graph of FIG. 2; the wing antisymmetric bending torsional flutter taking the engine dynamic characteristics into account and the wing antisymmetric bending torsional flutter normalization results without taking the engine dynamic characteristics into account are shown in a graph in FIG. 3. The diamond symbols in fig. 2 and 3 represent normalized flutter frequency and the square symbols represent normalized flutter velocity.

Claims

1. A method of aeroelastic analysis taking into account the dynamic characteristics of an engine, said method comprising the steps of:

extracting an engine reference point;

engine thrust stiffness correction matrix

gyro moment damping correction matrix

ΔM^*＝Φ^TΔMΦ，ΔD^*＝ΦTΔDΦ，ΔK^*＝Φ^TΔKΦ

wherein, Δ M^*Is a quality correction matrix, phi is a mode matrix;

2. A method of aeroelastic analysis taking into account engine dynamics, as set forth in claim 1, wherein: if the engine has the pitch angle beta, generating a following conversion matrix, and multiplying the conversion matrix by a damping correction matrix and a rigidity correction matrix to obtain the damping correction matrix under the state that the engine is considered to be installed with the pitch angle beta

And stiffness correction matrix

And then, substituting the rigidity correction matrix and the damping correction matrix in the state of considering the mounting pitch angle of the engine into the step three, and correcting the aeroelastic motion equation without considering the dynamic characteristic of the engine.

3. A method of aeroelastic analysis taking into account engine dynamics, as set forth in claim 1, wherein: and determining the position of the engine in the aeroelastic motion equation matrix through an engine reference point, wherein the engine reference point is the gravity center of the engine or the loading point of the thrust of the engine.