几何大变形太阳能无人机非线性气动弹性稳定性研究  

Exploring Aeroelastic Stability of Very Flexible Solar Powered UAV with Geometrically Large Deformation

作　　者：王伟[1] 周洲[1] 祝小平[2] 王睿[1] 

机构地区：[1]西北工业大学航空学院,陕西西安710072 [2]西北工业大学无人机研究所,陕西西安710065

出　　处：《西北工业大学学报》2015年第1期1-8,共8页Journal of Northwestern Polytechnical University

基　　金：国家自然科学基金(110202162;11302178);中国博士后科学基金(2014M560803)资助

摘　　要：大柔性太阳能无人机在气动载荷的作用下产生较大的弯曲变形,机翼结构的刚度、质量分布等特性亦发生较大改变,线性理论无法满足这类飞机气动弹性稳定性分析的精度要求。基于Co-rotational(CR)理论,推导了结构变形后的切线刚度矩阵和质量矩阵,建立了大柔性机翼结构动力学模型;采用建立在局部气流坐标系下的片条非定常气动力模型,建立了考虑几何非线性效应的大柔性无人机气动弹性运动方程。引入准模态假设,采用P-k法研究了几何大变形对类"太阳神"布局太阳能无人机的气动弹性稳定性的影响。研究结果表明:随着弯曲变形的增加,非线性颤振速度可降低10%以上,非线性颤振频率可下降8%;合理的增加扭转刚度、前移弹性轴、前移剖面质心等,均可以有效改善几何大变形引起的不利影响。研究工作对大柔性飞机的气动弹性设计具有一定的参考意义。A very flexible solar powered UAV under aerodynamic loading undergoes large deformation, thus chan- ging the stiffness characteristics and mass distribution of its wing structure. It is impossible to obtain its precise aero- elastic stability with the linear theory. Therefore we use the co-rotational theory to develop the aeroelastic stability a- nalysis algorithm suitable to a very flexible aircraft, derive the expression of tangent stiffness matrix and mass matrix of a spatial two-node beam element, and establish the dynamic model of a geometrically nonlinear structure. Using the unsteady aerodynamic strip model and the quasi-mode assumption, we derive the aeroelastic motion equations. We use the P-K method to analyze the aeroelastic stability characteristics of a solar- powered UAV with the layout similar to Helios under sis results given in Tabl geometrically large deformation. The analysis results on a test are compared with other analy- e 2, and they show good agreement ： as the wing deformation increases, the nonlinear flutter speed decreases by 10%, and the nonlinear flutter frequency decreases by 8% ; the aeroelastic stabilities of a solar- powered UAV will be improved by increasing torsional rigidity or by moving its elastic axis and the mass center of its wing section toward the leading edge.

关 键 词：几何大变形 CR理论 切线质量矩阵 大柔性机翼 非线性颤振 太阳能无人机 

分 类 号：V215.3[航空宇航科学与技术—航空宇航推进理论与工程]