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针对航空发动机三支点柔性转子系统的支承不同心问题,充分考虑转子结构特征和载荷特征,首次将当量刚度引入多支点柔性转子不同心问题的动力学分析,定量描述转子系统各支承间不同心度带来的转子轴段刚度非线性,并提出了多跨度柔性转子系统支承不同心激励的数学描述,建立了不同心激励下多跨度柔性转子系统的力学模型。基于Lagrange能量法,给出了转子系统动力学方程的求解方法,研究得到了支承不同心转子系统的动力响应特征。结果表明:支承不同心不仅引起转子过渡轴的刚度非线性,产生2倍频激励,还会给转子系统带来附加不平衡激励;对于三支点柔性转子系统而言,2倍频分量同样是支承不同心下转子系统振动响应的典型特征之一。转子系统2倍频分量随不同心量的增加而迅速增加,而1倍频分量基本保持不变。同时转子振动响应呈现“缓增速降”趋势,且随非线性刚度、不平衡量的增大愈加明显。
Aero-engine three-fulcrum flexible rotor system with different concentricity is considered. Considering the structure and load characteristics of the rotor, the equivalent stiffness is first introduced into the dynamics analysis of the multi-fulcrum flexible rotor with different concentric problems. Quantitative description of the different concentricity The rotor stiffness of the rotor is nonlinear, and the mathematical description of the multi-span flexible rotor system supporting different core excitation is proposed. The mechanical model of the multi-span flexible rotor system with different core excitation is established. Based on the Lagrange energy method, the solving method of the rotor system dynamics equation is given. The dynamic response characteristics of the system with different toroidal rotors are obtained. The results show that the support of different centers not only causes the nonlinear stiffness of the transition shaft of the rotor, but also produces additional double-frequency excitation and brings additional unbalanced excitation to the rotor system. For the three-point flexible rotor system, the second harmonic component is also supported One of the typical characteristics of the rotor system vibration response under different heart. The second harmonic component of the rotor system rapidly increases with different cardiac masses, while the first harmonic component remains unchanged. At the same time, the vibration response of the rotor shows a trend of “increasing and decreasing rapidly”, and with the nonlinear stiffness, the unbalance increases more obviously.