双盘转子碰摩故障动力学特性分析
Analysis of Dynamic Characteristics of Rub-Impact Fault of Double-Disk Rotor

针对两端刚性支承的动力涡轮双盘转子，使用符合库伦摩擦定律的局部碰摩力模型来定义其径向摩擦力与切向摩擦力。利用Timoshenko梁单元对其进行动力学建模，推导出单元的刚度矩阵和质量矩阵，并将各个单元矩阵组装成系统的总矩阵，写出整个系统的微分方程。采用Newmark-β方法对双盘碰摩故障转子系统进行解析，分别揭示了两个盘的碰摩间隙、接触刚度、摩擦系数对系统动力学特性响应的规律。分析结果表明：该系统呈现出多周期、拟周期和混沌等丰富的非线性动力学特性；碰摩引起振动主要为其自振频率成分，同时伴有其它较小的分数倍频振动及两侧相加为2倍频的分频。
For a power turbine double-disk rotor with rigid supports at both ends, the radial friction force and tangential friction force are defined by a local friction force model in accordance with Coulomb’s law of friction. The stiffness matrix and mass matrix of the element are derived by using Timoshenko beam element for dynamic modeling, and each element matrix is assembled into the total matrix of the system, and the differential equation of the whole system is written. The Newmark-β method was used to analyze the rotor system with rub-impact fault of two disks, and the response laws of rub-impact clearance, contact stiffness and friction coefficient of two disks to the system dynamic characteristics were revealed respectively. The analysis results show that the system presents rich nonlinear dynamics characteristics such as multi-period, quasi-period and chaos. The vibration caused by rubbing is mainly the natural frequency component, accompanied by other smaller fractional frequency doubling vibration and the frequency division which adds up to 2 times frequency on both sides.