考虑激励幅值慢变的卷绕头转子系统动力学建模

Dynamic modeling of winding head rotor system considering slow variation of excitation amplitude

卷绕头转子系统结构之间的耦合振动和时频变激励使振动问题十分复杂,为了更准确地研究其动力学特性,根据转子动力学理论,使用有限元方法建立了考虑多盘质量慢变的卷绕头非线性转子系统整机动力学模型,运用Newmark-β数值积分方法对其动力学特性求解,得到仅存在初始不平衡量以及卷装不良带来的激励频率、幅值慢变下的非线性动力学行为。通过分析轴心轨迹、时域波形和幅频特性曲线等结果,发现卷绕头转子系统对因卷装不良引起的激励幅值慢变较为敏感,出现新的频率成分。进一步对比分析了不同节点处的振动频谱,其结果可为卷绕头转子系统动力学设计和故障识别提供一定理论支持。

The coupling vibration between the complex rotor system structures of winding head and time-varying frequency excitation make the vibration problem extremely complex.To study its dynamic characteristics more accurately,based on the finite element method,this paper builds the nonlinear rotor system dynamics model of winding head considering the slow change of multi disk mass by using Newmark-βnumerical integration method to obtain the dynamic characteristics.The dynamic response is obtained when there are only initial imbalance and additional imbalance caused by poor winding.An analysis of the calculation results of axis trajectory,time domain response and frequency domain response curve shows the winding head rotor system is more sensitive to the slow change of excitation amplitude caused by poor winding,and new frequency components appear.The vibration spectra at different nodes are further compared and analyzed.Our study may lend some theoretical support for the dynamic design and fault identification of winding head rotor system.