考虑剪切和翘曲影响的直升机旋翼气弹稳定性分析

在中等变形梁理论的基础上,对桨叶变形体进行有限变形分析,推导出同时考虑剪切和翘曲影响的小应变、中等变形梁应变-位移关系,并构造出一个全新的21自由度梁单元,应用Hamilton原理导出桨叶运动的有限元方程。在此基础上,研究了剪切和翘曲等非经典因素对无铰旋翼桨叶的动特性和悬停时气弹稳定性的影响。数值结果表明:剪切和翘曲对旋转桨叶的固有频率,尤其是高阶频率,有一定的影响,特别是随着转速的提高这种影响会变大;同时对悬停时桨叶的气弹稳定性有相当程度的影响,尤其是在高桨距角下这种影响是不能忽略的。

Aeroelastic Stability for Helicopter Rotor Blades with Consideration of Transverse Shear Deformation and Warping

The aeroelastic stability behavior of a helicopter rotor blade in hover with transverse shear deforma- tion and warping is investigated by using the finite element method in this paper.A 21-DOF beam finite ele- ment,including transverse shear DOF and warping DOF,is developed for analysis.The governing differential equations of motion for hingeless rotor can be derived using the Hamilton's principle.Numerical simulations are carried out to validate the current analysis of other literature.The influences of transverse shear deforma- tion and warping on the natural frequencies and aeroelastic behavior of soft-in-plane hingeless rotor blade are investigated.With the inclusion of transverse shear and warping,there is a decrease in the rotation natural fre quencies.It is also seen that the transverse shear deformation and warping have effects on the aeroelastic sta- bility of the rotor blade.These effects become larger at the higher thrust level.