| The dynamic load identification technology as the structural dynamics of the second category of inverse problem, in recent years more and more get the attention of people, and studied out some effective identification method. In this paper, by using the theory of orthogonal polynomial to study the helicopter blade model distribution dynamic load.This article obtains from the inverse problem, discuss the ill-posed problem. To construct a onedimensional Chebyshev orthogonal polynomial expression, through computer simulation verify its various functions can be used for fitting. Is obtained by rotating blade dynamic equation is derived, the theoretical solution and finite element solutions. Frequency response function, and the principle of finite element software to calculate frequency response function. Using the theory of orthogonal polynomial load identification problem in rotating blade frequency-domain is derived, and noise of different sizes, different constraint conditions and measuring points is the computer simulation analysis is insufficient. Finite element modeling of the blade model, compared with modal parameters identification test results to ensure the accuracy of the models. Blade model installed in the helicopter rotor test bed frame, the strain gauge measurement of blade section bending moment as the output response of the load identification. Dynamic calibration on finite element model of test condition, to determine in this condition can also identify out load. Using time-frequency transform bending moment in the time domain signal into frequency domain, frequency domain method to identify the model of blade dynamic load distribution, analyzes the reason of error may occur.In this paper, from the theoretical derivation, the computer simulation and experiment, studies the helicopter blades rotating condition distribution dynamic load model in the frequency domain, and have some practical value in engineering. |
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