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Non-linear optimization algorithm for rational approximation of unsteady aerodynamic minimum state

A technology of unsteady aerodynamics and nonlinear optimization, which is applied in computing, electrical digital data processing, special data processing applications, etc., and can solve problems such as low efficiency and limited accuracy

Active Publication Date: 2015-11-11
NORTHWESTERN POLYTECHNICAL UNIV
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Problems solved by technology

[0004] In order to overcome the shortcomings of the existing methods with limited precision or low efficiency, the present invention proposes a nonlinear optimization algorithm for rational approximation of the minimum state of unsteady aerodynamic forces

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  • Non-linear optimization algorithm for rational approximation of unsteady aerodynamic minimum state
  • Non-linear optimization algorithm for rational approximation of unsteady aerodynamic minimum state
  • Non-linear optimization algorithm for rational approximation of unsteady aerodynamic minimum state

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Embodiment Construction

[0086] This embodiment is a nonlinear optimization algorithm for the rational approximation of the unsteady aerodynamic minimum state of the M6 ​​wing of the NACA0012 symmetrical airfoil. The root of the wing is completely fixed. The parameters of the wing are as follows: the root chord length is 0.8139m, the wing tip chord length is 0.4573m, the span length is 1.1963m, the leading edge sweep angle is 30°, the trailing edge sweep angle is 15.8°, no twist angle, Mongolia The thickness of the skin is 0.002m, the thickness of the beam web is 0.0015m, the thickness of the wing rib is 0.0015m, the material is aluminum alloy, the elastic modulus E=70GPa, Poisson’s ratio μ=0.30, and the density is ρ=2.7×10 3 kg / m 3 .

[0087] The concrete process of this embodiment is:

[0088] Step 1, establish the finite element model and aerodynamic model of the wing, and calculate the generalized aerodynamic coefficient matrix of the wing at a given shrinkage frequency, specifically:

[0089]...

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Abstract

The invention discloses a non-linear optimization algorithm for rational approximation of a unsteady aerodynamic minimum state. According to the non-linear optimization algorithm, key model lines of a matrix D are initialized; then, each column of a matrix E and the rest of lines of the matrix D are sequentially solved; function value information at a current sequential solving method on each column of matrix E and other lines of matrix D; and the function iteration point is sufficiently utilized, so that approximate precision of the inverse Hessian matrix is effectively improved, and the efficiency of an outer-layer non-linear optimization algorithm is improved. According to the non-linear optimization algorithm, fitting precision of elements in the key model lines of a general aerodynamic matrix is effectively improved, so that the precision of time-domain flutter analysis results and the gust response analysis results is increased in a facilitated mode. A discrete unsteady aerodynamic coefficient matrix in the frequency domain is extended to the Laplace-domain in the form of an MS algorithm; and the computing efficiency and the precision of the key model can be effectively improved.

Description

technical field [0001] The invention relates to the field of aeroelasticity, in particular to a nonlinear optimization method for rational approximation of unsteady aerodynamic force in the frequency domain. Background technique [0002] In order to facilitate the multidisciplinary optimal design of the aeroservoelastic system, it is necessary to convert the motion equation of the elastic vehicle into a first-order time-invariant state-space equation in the time domain, and the unsteady aerodynamic model of the structure under arbitrary motion is one of the keys component. In the case of subsonic or supersonic speed, the generalized unsteady aerodynamic coefficient matrix (GAF) calculated based on the dipole grid method is a function of a series of given reduced frequencies, representing the structure under simple harmonic oscillation. generalized aerodynamic force. In order to transform the generalized aerodynamic force into the time domain space, it needs to be approxima...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCY02T90/00
Inventor 刘祥孙秦李亮
Owner NORTHWESTERN POLYTECHNICAL UNIV
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