中文摘要：

建立了带有裂纹一支承松动耦合故障的具有三轴承支承的双跨弹性转子系统的动力学模型，并对系统裂纹、松动及其耦合故障对系统非线性动力学响应的影响进行了数值仿真研究．当只有裂纹故障时，在亚临界转速和超临界转速区均有拟周期运动；当只有松动故障时，在亚临界转速区为拟周期运动，而在超临界转速区为混沌运动．当出现裂纹-松动耦合故障时，松动故障的影响占主要地位，同时有较大范围的周期3运动区间出现．随着裂纹深度的增加，其影响作用逐渐增大．研究结果为转子轴承系统故障诊断、动态设计和安全运行提供了理论参考．

英文摘要：

A dynamic model was set up for the two-span rotor-bearing system with coupling faults of crack and pedestal looseness supported on three plain journal bearings. The nonlinear dynamics behaviors that induced by crack, pedestal looseness and coupling faults are numerically studied. In the case of crack faults, quasi-periodic motion appears within the range of sub-and super-critical speed range. When the pedestal looseness fault occurs, the quasi-periodic motion appears in the sub-critical speed range, but chaotic motion takes place within the super-critical speed range. The pedestal looseness fault is the main influence on the coupling fault system,and there is period-3 motion appearing in the system. The influence of crack fault increases along with the depth of crack. The results may provide theoretical references for fault diagnosis, dynamic design, and safe operation of rotor-bearing system.