一种直升机驾驶舱振动水平减振实践

A horizontal vibration reduction practice for helicopter cockpit

某型直升机在试飞过程中,驾驶舱的振动在某一过渡速度区域,存在振动水平过大的问题。为定位并解决该问题,首先对直升机振动传递的一般规律进行分析;其次,对该型直升机驾驶舱、旋翼、主减等振动传递路径上的实测振动及载荷参数进行分析,明确造成驾驶舱振动水平过大的旋翼谐波激振力频率为旋翼转速频率的5倍;针对该谐波频率,提出在旋翼挥舞方向增加吸振摆锤的方案,并在型号试飞中实践,最终实现预期的驾驶舱振动水平减振的目的,主桨叶根部挥舞弯矩振动幅值最大减少65%。该方法解决该型号过渡速度区域驾驶舱振动水平过大的问题,也为后续直升机型号飞行试验阶段的振动排振和减振积累宝贵的经验。

During the flight test of a helicopter,the vibration level of cockpit is too high in a certain transition speed area.In order to locate and solve the problem,firstly,the general law of helicopter vibration transmission is analyzed.Secondly,the measured vibration and load parameters on the transmission path of the cockpit,rotor and main reducer of the helicopter are analyzed,and the frequency of the harmonic excitation force of the rotor which causes the excessive vibration level of the cockpit is 5 times the frequency of the rotor speed.For this harmonic frequency,a scheme is proposed to add the vibration absorbing pendulum in the direction of rotor flapping,and the engineering practice is carried out by flight test,finally,the expected purpose of horizontal vibration reduction of cockpit is realized,and the vibration amplitude at the root of the main blade is reduced by 65%.This method solves the problem that the vibration level of cockpit in the transition speed region is too high.It also accumulates valuable experience for the vibration elimination and vibration reduction of the following helicopter in the flight test stage.