Research On Parametric Modeling Of Composite Blade And Design Optimization To Rotor Dynamics

Frequency modulation design, which is the necessary conditions of the dynamic design of vibration reduction and stability, is the basic components of the helicopter rotor dynamic design. Traditional frequency modulation design is a typical iterative modification process of man-in-theloop. The design process often relies on the distilled experience of expert designers, and only gets the feasible solution. Hence, by basing on the parameterized models, using the optimization technology, we can greatly improve the quality and efficiency of rotor frequency modulation design.This article focuses on the parameter modeling method and FM(frequency modulation) optimization method of the helicopter composite rotor blades, which is basing on the parameterized models this article structured.This paper discusses the structure characteristics of typical composite rotor blades in detail, comes up with an effective parametric modeling method, and establishes the automatic mesh generation method of the typical composite blade section. Then, basing on the parametric modeling program of the helicopter composite rotor blades that this author writhed, we achieve parametric modeling function for a variety of forms of blade profiles. With metal rotor blades, ball-bearing rotor blade engineering models, and "dolphin" helicopter composite blades, for example, parametric calculating method is analyzed to be fit for different models.Based on the Hodges moderate deflection beam theory, the blade nonlinear dynamic model is developed, which is used 5 nodes and 15 degrees of freedom beam finite element model. For the bearingless rotor configuration with multiple load paths, dynamic boundary constraint models that this article developed, which will ensure the displacement consistencies, realizing dynamic characteristic exact analysis of the bearingless rotor configuration. With ball-bearing rotor blades, bearingless rotor configuration with multiple load paths, SA349 helicopter composite blades, for example, the accuracy of the nonlinear dynamic model that this article developed is verified.In terms of frequency modulation design, this paper presents "direct optimization", "hierarchical o ptimization" optimization strategies, realized the blade frequency optimazation design. The two kinds of FM optimization strategy were proved and invalidated.