中文摘要：

基于二维三自由度耦合颤振分析方法，对平板断面经典扭弯耦合颤振的颤振驱动机理和颤振形态进行了深入研究。研究结果表明经典扭弯耦合颤振仍然是由气动负阻尼驱动的，“气动刚度驱动”的机理解释是不正确的，而气动负阻尼主要来源于系统扭转和竖向自由度运动之间的耦合效应。颤振形态矢量的分析结果显示经典扭弯耦合颤振发生时竖向自由度参与程度较高，表明扭转和竖向自由度的耦合效应相当强烈。对颤振形态同结构扭弯频率比以及颤振形态同结构颤振性能的关系进行了分析，虽然颤振形态同结构扭弯频率比之间存在简单、唯一的对应关系，但颤振形态同结构颤振性能的关系则比较复杂。最后对发生于平板断面的竖弯形态颤振的机理进行了探讨。

英文摘要：

Based on the analytical method （2d-3DOF method） for two-dimensional three degrees of freedom coupling flutter, the flutter-driving mechanism and flutter modality of the classical coupled bending-torsional flutter phenomenon about thin plate sections were investigated. The research results indicate that the classical coupled flutter is driven by negative aerodynamic damping, and the ＂aerodynamic stiffness driving mechanism＂ is incorrect. The negative aerodynamic damping mainly comes from coupling effects between torsional and heaving motions of the whole system. The calculated flutter modality vector at flutter onset reveals that the participation level of heaving motion in the flutter phenomenon is very high, which implies that strong coupling effect exists between motions in different degrees of freedom. Then both the relationship between flutter modality and torsion-bend-frequency ratio and the relationship between flutter modality and structural flutter performance were analyzed. It is found that although there is a simple and unique relationship between flutter modality and torsion-bend-frequency ratio, the relationship between flutter modality and structural flutter performance is rather complicated. The mechanism of heaving-type flutter about thin plate sections was also discussed.