直升机传动轴的纵向振动分析

传动轴的纵向振动影响横向弯曲振动的稳定性及振幅,使轴端的花键微动摩擦及磨损。根据质心运动定理和Galerkin法建立和求得非惯性系下倾斜两端支承传动轴的纵向运动方程。在此基础上,用多尺度法求得纵向运动方程的一次近似解,并进一步求得纵向位移,分析了纵向振动的规律等。研究表明传动轴的非共振的纵向振动是小振幅、振幅按指数规律衰减、渐进稳定的振动,稳态纵向振动的振幅很小。传动轴的重力和偏心质量产生的惯性力引起纵向振动。传动轴的纵向振动无法消除,对传动轴的安全性构成威胁的可能性很小。

Analysis of Longitudinal Vibration of a Helicopter Drive Shaft

Under non-inertia movement coordinate system, a longitudinal motion equation of a tilting drive shaft with two supports is derived according to mass center movement theorem and making use of galerkin method. An approximate solution of the equation is obtained by method of multiple scales. According to the solutions, the longitudinal deflection of a drive shaft is obtained. The regularity of longitudinal vibration is analyzed. The results show that the longitudinal vibration of non-resonant drive shaft is of exponentialy damped small amplitude and of asymptotic stability. Amplitude of stable longitudinal vibration is much smaller. Longitudinal vibration of a drive shaft is caused by the gravity and inertia force due to mass eccentricity and can not be removed. There is vare possibility that the longitudinal vibration of a drive shaft will threaten the safety.