直升机复合材料传动轴的主共振分岔分析

传动轴主共振分岔时,振幅突变,有可能运动失稳。在根据质心定理和Galerk in法求得非惯性移动系下直升机的倾斜两端支承纤维增强复合材料传动轴的弯曲运动方程基础上,用多尺度法求得稳态下主共振的分岔方程,再分析了运动稳定性、幅频响应曲线的拓扑结构等主共振分岔问题。得到了复合材料传动轴比钢、铝合金传动轴运动稳定性好等结论。提出通过加大阻尼使传动轴主共振不分岔。在挠度大的轴段上增加阻尼能使传动轴主共振不分岔,并能充分发挥阻尼的作用,优化轴的重量。

Bifurcation Analysis of Main Resonance of a Composite Drive Shaft of Helicopter

When bifurcation of main resonance occurs to a drive shaft, its amplitude jumps and perhaps its motion is instable. Based on bending motion equation of a tilting fiber composite drive shaft of a helicopter with two inclined supports obtained under non-inertia movement coordinate systems by theorem of the motion of center of mass and the method of Galerkin, a bifurcation equation of the steady-state main resonance is obtained by using the method of multiple scales. The motion stability, topological structure of amplitude-frequency response curves and so on are analyzed. The conclusion that the motion stability of a fiber composite drive shaft is better than that of a drive shaft of steel or aluminum is arrived at. The paper points out that the bifurcation of main resonance is removed by increasing damping. In case of increasing damping in the section of larger deflection of a shaft, the bifurcation of main resonance can be removed, the effect of the damping is fully brought into play and the weight of the shaft is optimized.