具有不对称间隙的二元机翼颤振研究

利用数值方法分析了有预荷载情况下具有不对称间隙的气动弹性非线性与结构非线性耦合的二元机翼颤振问题的动力学响应,研究了当速度比U^*/U_L^*从零逐渐增大到1时系统的全局演化规律,分析了频率比ω、机翼质量密度比μ、预荷载M₀、初偏值α_f、间隙δ及初始条件等参数对颤振临界点的影响,发现在有预荷载的不对称分段线性系统中不存在混沌运动形式,而且系统幅值的变化规律不受初值条件的影响,并根据引起俯仰幅值变化的敏感参数,提出几种控制和减小颤振的方法,可用于指导飞机的飞行结构设计及飞机结构的日常维护。

THE FLUTTER STUDY OF A TWO-DIMENSIONAL AIRFOIL WITH ASYMMETRY FREEPLAY

The dynamic response of a two-dimensional airfoil with preload asymmetry freeplay, which is of coupled aeroelastic nonlinearity and structural nonlinearity, is analyzed using numerical method. Global bifurcation of the system is investigated as the speed ratio U * / UL* increases from zero to 1 gradually. The effects on the critical flutter point are investigated when the natural frequency ratio ω , freeplay clearance δ , airfoil-air mass ratio μ , preload M 0, initial deflection α f and the initial values are varied. It is found that the chaotic motion does not occur in the asymmetry freeplay system and the amplitude of flutter motion is not affected by the initial values. Some useful suggestion for the airfoil design and maintenance are given in terms of the sensitive parameter leading to the change of the pitch-motion amplitude.