大展弦比飞翼刚弹耦合运动稳定性分析  

Dynamic Stability Analysis of a Flying Wing Considering the Rigid-Elastic Coupling Effects

作　　者：王立波 唐矗[3] 杨超 

机构地区：[1]中航工业第一飞机设计研究院总体气动设计研究所,陕西西安710089 [2]北京航空航天大学航空科学与工程学院,北京100191 [3]中航工业第一飞机设计研究院强度设计研究所,陕西西安710089

出　　处：《西北工业大学学报》2017年第6期1096-1104,共9页Journal of Northwestern Polytechnical University

摘　　要：推导了平均体轴系下弹性飞机的刚弹耦合运动方程,然后基于小扰动假设将其线化,综合有理函数拟合得到的时域非定常气动力模型,建立了可用以弹性飞机刚弹耦合运动学稳定性分析的状态空间模型。对某大展弦比飞翼布局无人机的纵向刚弹耦合运动稳定性进行了建模与计算。结果显示随着飞行速度的增加,机翼对称一弯模态与短周期运动模态发生耦合,使得飞翼在较小的飞行速度下就出现自由体颤振现象,表明结构弹性会对飞翼纵向动力学稳定性造成显著的影响,在大展弦比飞翼设计过程中应当引起重视。研究了在刚弹耦合状态空间建模过程中,截取弹性模态阶次的多少对稳定性分析结果的影响。分析了结构刚度对飞翼刚弹耦合运动稳定性的影响。计算表明刚弹耦合失稳速度随机翼刚度的增加呈近似线性增加的趋势。在相同速度水平下,弹性飞翼的短周期频率和阻尼值均随着机翼刚度的增加而增加。The motion equation of a flexible aircraft have been derived based on the mean axes, which consider the rigid-body degrees of freedom as well as the elastic degrees of freedom of aircraft. The unsteady aerodynamics in time domain is computed by rational function approximation. The linear state-space model of the aircraft is then established based on the small disturbance theory, which could be used for flight dynamic stability analysis of the flexible aircrafts. For instance, the longitudinal stability analysis of a flying wing with large-aspect-ratio wings has been modeled and analyzed. The root locus indicates that an unsteady phenomenon called the free-body-flutter appears at a low speed, because the first structural bending mode will interact with the short-period mode, which means the structural flexibility will have a great influence on the flight stability of the flying wing, and that should be considered during the aircraft design procedure. Moreover, the effects by the number of elastic modes that have been used to establish the state-space model and the stiffness of the wing structure on the flight stability have also been studied. The result indicates that the stability critical speed of the flying wing will increase with the stiffness linearly. The frequency and damping of the short-period mode of the flying wing will also increase with the stiffness, if the velocity is frozen.

关 键 词：气动弹性 弹性飞机 动力学稳定性 飞翼 

分 类 号：V212.12[航空宇航科学与技术—航空宇航推进理论与工程] V215.3