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飞机前起落架的摆振是飞机在地面滑跑时产生的一种有害的自激振动。基于多体动力学理论,建模时运用点线耦合的方法处理起落架缓冲器的柔性化问题。采用子结构模态法建立刚柔耦合模型,考虑了起落架结构的弹性以及机体的刚性运动。通过线性化计算得出前起落架的典型模态,并对模型进行了校验,给出了以飞机速度和临界防摆阻尼系数组成的飞机摆振稳定区域图,研究了前起落架柔性、机体重心设置和机身刚体运动对摆振稳定性的影响。结果表明,前起落架结构柔性对摆振稳定性影响较大,且在低速滑跑时的影响更为突出;飞机重心后移,有利于提高摆振稳定性;机身刚体运动对于前起落架摆振的影响不可忽略。
Shimmy of the nose gear of the aircraft is a detrimental self-excited vibration that occurs when the aircraft rolls over the ground. Based on the multi-body dynamics theory, the flexibility of the landing gear bumper is dealt with by the method of point-line coupling. Rigid-flexible coupling model was established by using sub-structure modal method, taking into account the elasticity of landing gear structure and the rigid motion of the body. The typical modal of nose landing gear is obtained through linearization calculation, and the model is calibrated. The regional stability map of the aircraft is given with the aircraft speed and critical damping coefficient. The effects of nose gear flexibility, Influence of Center of Gravity and Body Rigid Motion on the Shimmy Stability. The results show that the flexibility of the nose gear has a great influence on the stability of the shimmy gear, and the impact is more prominent when the gear is spun at low speed. The center of gravity of the aircraft moves backward to improve the stability of the shimmy. The effect of shimming can not be ignored.