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Flutter boundary prediction method in wind tunnel flutter test under turbulence excitation condition

A prediction method and flutter technology, which is applied in the testing of machines/structural components, vibration testing, measuring devices, etc., can solve the problems of turbulent flow natural excitation response modal parameter identification, etc., to improve the judging method of flutter and improve the accuracy Effects on sex and safety

Inactive Publication Date: 2014-01-22
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

[0006] Aiming at the wind tunnel flutter test under the turbulent excitation condition, the present invention provides a flutter boundary prediction method for the wind tunnel flutter test under the turbulent excitation condition, aiming at solving the model of the turbulent natural excitation response in the wind tunnel test. State parameter identification problem

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  • Flutter boundary prediction method in wind tunnel flutter test under turbulence excitation condition
  • Flutter boundary prediction method in wind tunnel flutter test under turbulence excitation condition
  • Flutter boundary prediction method in wind tunnel flutter test under turbulence excitation condition

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Embodiment Construction

[0028] The technical scheme of the present invention is described in detail below in conjunction with accompanying drawing:

[0029] Please refer to Figure 1 to Figure 10 As shown, the wind tunnel flutter test flutter boundary prediction method under the turbulence excitation condition of the present invention comprises the following steps:

[0030] (1) Select the measuring points of the bending and torsion modes of the model to paste the sensors, and collect the responses of each point in real time during the blowing process. The sampling frequency is 4096Hz, and the bending and torsion responses when the wind speed is 41m / s are as follows: figure 1 shown;

[0031] (2) Under the wind speed, trend removal and smoothing are performed on the measured response to achieve the purpose of removing burrs and bad points. The processed response is as follows figure 2 shown;

[0032] (3) Autocorrelate the turbulence response signal after preprocessing of each measurement channel to...

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Abstract

The invention discloses a flutter boundary prediction method in a wind tunnel flutter test under a turbulence excitation condition. At first, time domain response signals of typical measuring points in the process of the wind tunnel test are collected, trend removal and smooth pretreatment are carried out on the signals, self-correlation processing is conducted on processed turbulence response data, the processed turbulence response data serve as impulse responses of a system, band-pass filtering is carried out on the processed turbulence response data, and frequency selected by filtering is determined by dangerous modal frequency measured by a model ground resonance test; secondly, spectral analysis and modal parameter identification are carried out on the obtained and processed impulse responses with noise, and an MPM with high anti-noise performance is adopted to identify various order modal parameters; at last, frequency and damping ratios of various order modals are arranged according to different wind speeds when data are collected, and a mode that straight line fitting and polynomial fitting are combined is adopted to extrapolate a flutter boundary. According to the method, the flutter boundary under the turbulence excitation condition can be forecasted, a traditional flutter judgment method is improved, and improvements of accuracy and safety of the test are facilitated.

Description

technical field [0001] The invention relates to a modal parameter identification method, in particular to a flutter boundary prediction method for a wind tunnel flutter test under turbulent flow excitation conditions, and belongs to the technical field of modal parameter identification. Background technique [0002] The flutter test is an important part of the aircraft design work. The flutter boundary obtained through the test can determine the flight envelope of the aircraft, and then evaluate the performance of the aircraft and ensure flight safety. [0003] However, currently in wind tunnel flutter tests, the acquisition of flutter velocity usually depends on the working experience of the testers. Using the flutter boundary calculated by finite element elements as a reference value, the testers will increase the wind speed with a certain wind speed step in the initial stage of blowing, and then continuously reduce the speed increase of the wind speed step. When the wind ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F19/00G01M7/02
Inventor 周丽李扬穆腾飞
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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