建立了在汽轮机非线性间隙气流激振力作用下裂纹转子－轴承系统的动力学分析模型，并采用数值积分方法研究此类裂纹转子系统的分岔与混沌特性。利用 Poincare 截面和分岔图的变化分析汽轮机非线性间隙气流激振力和裂纹深度对系统振动响应特性的影响。分析结果表明：汽轮机非线性间隙气流激振力会使得系统的周期性运动状态提前，且混沌区域发生明显的减小；在浅裂纹时，汽轮机非线性间隙气流激振力对系统的响应起主导作用，且在超临界转速区域出现周期8运动；随着裂纹深度的增加，系统运动的混沌区域逐渐减小几乎消失，在超临界转速区域的逆周期运动演变为较长的周期3运动。研究结果可以作为含裂纹转子在汽轮机非线性间隙气流激振力作用下耦合故障发生的典型特征，也可作为此类耦合故障诊断的依据。%The dynamic model of a cracked rotor-bearing system under air-exciting forces of steam turbine was established.Numerical method was adopted to analyze bifurcation and chaos characteristics of the system.The effects of air-exciting forces of steam turbine and depths of crack on the vibration response of the rotor were discussed using Poincare's cross-section,portraits of central point and bifurcation diagrams.The results indicated that the dynamic periodic responses of the system occur in advance and its chaotic motion region decreases due to air-exciting forces of stream turbine;moreover,for the dynamic responses of the system,the air-exciting forces of stream turbine play a dominant role in case of shallow cracks,and period-eight motions appear in the super-critical speed region of the system;with increase in crack depth,the system's chaotic motion region decreases and almost disappears around the critical speed;the system's quasi-period motions become a longer period-three motion in the system's super-critical speed region. The study results provided a reference for further understanding the failure mechanism of such a rotor-bearing system.
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