直升机旋翼轴弯矩特征及应用

Characteristics and application of bending moments of helicopter rotor shaft

针对球柔性桨毂构型的直升机,分析了各支臂mΩ挥舞力动载、挥舞力静载不平衡量和摆振力动载、离心力动载、离心力静载不平衡量产生的旋翼轴弯矩的幅值、频率、相位和分布规律。对某直升机制定了飞行载荷测量方案,获取了测量数据,分析了旋翼轴弯矩的特征,建立了有效性判据,判别了无效数据,编制了实测载荷谱。某直升机的分析结果表明:在旋翼坐标系下旋翼轴动弯矩远大于静弯矩,旋翼各支臂挥舞力静载不平衡量和和离心力静载不平衡量较小;旋翼轴弯矩以1Ω载荷为主,主要由旋翼各支臂1Ω的挥舞力、摆振力和离心力产生;合成弯矩呈大小相等的旋转弯矩特征,沿旋翼轴不同周向位置的弯矩幅值相近,相位差与周向的夹角相同。

The rotor shaft bending moments are produced by mΩdynamic flapping forces,unbalanced components of static flapping forces,dynamic drag forces,dynamic centrifugation forces and unbalanced components of static centrifugation forces of the arms on spheriflex hub helicopters.The amplitude,frequency,phase position and distribution laws of rotor shaft bending moments are analyzed in this paper.After the flight load measurement for a helicopter is performed,the characteristics of the measured rotor shaft bending moments are analyzed,establishing the effectiveness criteria,distinguishing the non-effective data,and finally compiling the measured fatigue load spectrums.The analysis of the helicopter shows that in the rotor coordinate system,the dynamic moments are much larger than the static moments while the unbalanced static flapping force and static centrifugation force are small.The main components of rotor shaft bending moments are 1Ωmoments produced by the 1Ωflapping force,the drag force and the centrifugation force.The combined bending moments exhibit the same amplitude in one section rotating around the rotor shaft,the similar amplitude and the same phase difference with the different circumferential position along the shaft.