The non-linear dynamic behavior of rotor system with a misaligned journal bearing and non-circular cross section of shaft is analyzed in the present paper. Based on coordinate transformation, the non-linear dynamic model of the rotor system is derived under some assumptions such as the long journal bearings, small misalignment and tiny disk unbalance. Using numerical technique the nonlinear dynamic behaviors, such as steady state response, rotor center orbit. Poincare section and the largest Lyapunov exponent, are paid more attention. The results show that at low speed besides synchronous components with rotating speed according to unblance there exist multiple and combined frequency components according to misalignment. As the speed increases the bifurcation phenomena, such as periodic motions, chaotic oscillations occur.%研究了具有轴承不对中故障的柔性非圆截面多转子系统的非线性动力学特性.首先在长轴承、微小不对中量和不平衡量等假设下,利用坐标变换推导出非圆截面多转子-轴承系统的非线性动力学模型.最后采用数值方法,重点分析了系统的非线性振动行为,例如稳态响应、轴心轨迹、Poincaré截面以及最大Lyapunov指数等.结果表明:在较低转速时,转子系统除存在与不平衡故障同步的工频外,还存在由于不对中引起的倍频以及组合频率成分等.随着转速的提高,系统出现倍周期分叉现象,混沌运动等复杂的非线性动力学行为.
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