非线性结构气动伺服弹性稳定性分析

真实的气动伺服弹性系统通常都含有各种非线性因素,它们会对系统的特性带来不可忽略的影响.为此采用一种频域方法对带有间隙的非线性结构进行气动伺服弹性稳定性分析.在气动伺服弹性运动方程中,非线性的结构刚度通过描述函数法转化为准线性的等效刚度,然后采用线性控制理论中的Nyquist方法来判断气动伺服弹性系统的稳定性并计算稳定裕度.以某一飞机的带有扑动和旋转间隙的受控翼面为例进行了数值计算.结果表明,旋转间隙对系统的稳定性影响是主要的;旋转间隙越大,系统稳定裕度越小. 

Aeroservoelastic stability analysis of non-linear structure

The real aeroservoelastic systems usually have various nonlinear factors,which may induce unnegligible effects on the characteristics of the systems.A frequency-domain method was applied to analyze the aeroservoelastic stability on nonlinear structures with gap.In the equations of motion of the aeroservoelastic system,the nonlinear structural stiffness was transformed to the quasi-linear equivalent stiffness by using the describing function method.The stability and stable margin of the aeroservoelastic system were analyzed by Nyquist method in linear control theory.Numerical calculations were conducted on a controlled wing with flapping gap and rotating gap.The results indicate that the flapping gap is the major factor which affects the stability,and the bigger the flapping gap is,the worse the stability of the system gets.