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为了研究大展弦比机翼水平弯曲模态参与耦合时的颤振特性,首先用考虑几何非线性的颤振分析方法研究了某大展弦比机翼的颤振特性,建立了大展弦比机翼非线性颤振分析的简化模型,即盒段模型;然后通过组合不同的水平弯曲频率、扭转频率形成不同的接近模式,系统分析了不同接近模式对盒段模型非线性动力学特性的影响规律,提出了水平弯曲频率和扭转频率发生模态交换的存在条件。在此基础上通过对盒段模型进行非线性颤振分析发现:水平一弯模态参与耦合降低了机翼传统模式的线性颤振速度,增大水平一弯的频率有助于该类颤振速度的提高;在水平一弯频率和扭转频率逐步接近时,会导致机翼颤振速度显著下降,且颤振类型会由水平一弯和垂直弯曲耦合的颤振转化为水平一弯和扭转耦合的颤振。
In order to study the flutter characteristics of a large aspect ratio wing when the horizontal bending modes are involved in the coupling, the flutter characteristics of a large aspect ratio wing are studied by using the flutter analysis method considering geometric nonlinearity, Which is a simplified model of the nonlinear flutter analysis of the airfoil, that is, the box-section model. Then, different modes of horizontal bending frequency and torsional frequency are combined to form different modes of approximation. The nonlinear dynamics of the box model are analyzed systematically. The law of influence is proposed and the existence conditions of modal exchange between horizontal bending frequency and torsional frequency are proposed. Based on this, the nonlinear flutter analysis of box-section model shows that the horizontal-bending modal coupling reduces the wing flutter speed and increases the frequency of horizontal bending contributes to the flutter When the horizontal and vertical torsional frequencies are gradually approached, the flutter speed of the wing will decrease significantly, and the type of flutter will be transformed by the horizontal and vertical bending coupled flutter into horizontal and torsional coupling Flutter.