无轴承旋翼柔性梁载荷特性研究

Study on characteristics of flexbeam load of bearingless rotor

应用Hamilton原理建立了双路传力的无轴承旋翼运动方程。采用均匀入流模型,基于直升机飞行平衡条件,建立了无轴承旋翼柔性梁载荷的计算模型,并通过算例验证了模型的精度。利用该模型,研究了全机重心位置、机身气动阻力以及平尾安装角对柔性梁载荷特性的影响,给出了各因素对柔性梁载荷的影响趋势,得出了降低柔性梁载荷的方法。数值结果表明:2cm左右重心位置的变化能够引起9%~11%的柔性梁载荷变化量,15%气动阻力的增加会导致约9%的柔性梁载荷的增大;2°平尾安装角的变化引起约10%柔性梁载荷的变化量,3°平尾安装角的变化引起约26%柔性梁载荷的变化。

Bearingless rotors realize the motion of flaping,laging and ptiching by elastic deformation of a flexbeam,therefore,the flexbeam is subjected to complex alternating load.To accurately estimate the load on the flexbeam is one of the difficulties in the bearingless rotor technology.In order to solve this problem,the Hamiltonian principle is used to establish a two-way force-free bearingless equation of motion.By the uniform inflow model,the calculation model of the flexbeam load for the bearingless rotor is established based on helicopter flight balance conditions,and the accuracy of the model is verified by an example.Influences of the position of the center of gravity of the helicopter,the aerodynamic drag of the fuselage and the setting angle of the horizontal tail on flexbeam load characteristics are studied by the developed model.Effects of various factors on the load of the flexible beam are given,and several methods for reducing the flexbeam load are obtained.Numerical results obtained show that the flexbeam load can reach the ideal level by changing the position of the center of gravity of the helicopter,the aerodynamic drag of the fuselage and the setting angle of the horizontal tail.This conclusion can provide an important reference for aerodynamic layout design and integrated parameter design.