考虑间隙非线性的控制舵非线性气动弹性分析

间隙结构的气动弹性系统非线性颤振问题是飞行器气动弹性力学工程领域的研究热点和难点,研究 考虑间隙非线性的控制舵系统的气动弹性特性具有重要意义。基于最小状态拟合方法获得时域降阶气动力模 型,并通过Lagrange方程获得系统非线性气动弹性方程;对比分析三种不同非线性控制舵系统的极限环颤振 及非线性动力学响应特性,并与等效线化法和时域仿真的结果进行一致性对比。结果表明:俯仰和扑动弹簧刚 度的变化对系统颤振边界有显著影响,当俯仰和扑动两个方向同时含有间隙非线性时,系统在线性颤振速度内 存在倍周期、混沌等复杂非线性动力学现象。

Nonlinear Aeroelastic modelling and analysis of control fin with free-play nonlinearity

The nonlinear flutter problem of aeroelastic system with freeplay nonlinearity has become one of the hottest and most challenging topics in the engineering field of aircraft aeroelasticity. The nonlinear aeroelastic behaviors of the control fin with freeplay nonlinearity are analyzed in the study. The reduced-order aerodynamic model in time-domain is obtained by using the minimum state approximation method, and then the nonlinear aeroelastic equations of the control fin can be obtained based on the Lagrange equation. Using the numerical method, the aeroelastic system behaviors with freeplay nonlinearity in either pitch or plunge, or both of them are studied, including limit cycle oscillations (LCOs) and nonlinear dynamic responses. The numerical results are compared with those of the equivalent linearization method. The results show that the stiffnesses of pitch and plunge springs have significant influence on the flutter boundary of the system. And when the free-plays are both in pitch and plunge, there exists complex dynamic phenomena including the multi-periodic LCOs and chaotic motions.